Document ev49L9J9e8ZxXrqoOvOq5M844

mmm i I r- Hi /7T ''' o o 0 m' THE PROPER HANDLING OF AROCLORS AND THEIR MIXTURES IN THE ; - ELECTRICAL INDUSTRY ^ Monsanto Chemical Co. Organic Div. Sales Dept. Monsanto 800 N. Lindbergh Blvd. M _ St. Louis 66, Mo. P.G. BENIGN US Revised January 1960 DSW 356968 STLCOPCB4085790 { i INDEX Introduction - Page 1-2 The Proper Handling Of Arodors And Their Mixtures In The ,, Electrical Industry- { Chapter 1 - Page 3-12 Procedure For Unloading Tankcars Of Aroclors And Aroclor Mixtures Page 3 Page 4 Page 12 A) Description of the Cars !b] Procedure for Unloading the Car C) Drum Packaging . Chapter 2 - Page 13-19 Storage Tanks Page 13 Page 17 (A} General Description (B; Detailed Description Chapter 3 - Page 20-21A Page 20 Page 21 Gasketing and Pump Packing (A) Suggested Types Of Packing and Gasketing Materials (B) Gaskets For Askarel Capacitors and Transformers l Chapter 4 - Page 22-25 Sampling Methods v Page 22 (A) The ASTM Standard Method . Page 23 fB) Monsanto Methods j Page 25 (c) Drum Sampling j Chapter 5 - Page 26-28 Laboratory Analysis and Procedure Page 26 (A) For Treating Aroclors and Their Mixtures with Earth i j Chapter 6 - Page 29-61 Test Procedures * Page 29 (A) General Information Page 31 (B) Detailed Instruction and i . Testing Methods i Page 31 1. Procedure for Cleaning J Page 32 Electrodes 2. Dielectric Constant and Power Factor , Page 38 3. Dielectric s+woncth DSW 356969 STLCOPCB4085791 I$ * ii I ; i ? I. 1 j ; \ * \ I t I I 4 ^ * 1 Page 44 Page 47 Page 49 Page 51 Page 52 Page 55 Page 59 Chapter 7 - Page 62-73 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Chapter 8 - Page 74-76 Page 74 Page 74 Page 75 Chapter 9 - Page 77-79 Page 77 Page 77 Page 78 Page 79 4. Resistivity 5. Corrosion and Chemical Stability 6. Inorganic Chlorides 7. Acid Number 8. Moisture 9. Hydrolysis Stability Test for Aroclor 10. Thermal Stability Method for Aroclors Typical Properties Aroclor 1232 Aroclor 1242 Aroclor 1248 Aroclor 1254 Aroclor 1260 Pyranol l48l Pyranol 1488 Pyranol 1467 Pyranol 1470 Inerteen PPO Quality Requirements of Aroclors Prior to Use in the Electrical Industry Quality as Supplied to the Electrical Industry Typical Electrical Quality of Aroclors Used in the Industry Capacitor Impregnation Transformer Filling Earth Refinement of Aroclors to Arrive at the Desired Elec trical Qualities Earth Treatment in the Laboratory Preparatory to Analysis Earth Treatment by the Plant Manufacturing the Askarel Earth Refinement by the User Capacitor Manufacturers Transformer Manufacturers The Effect of Earth Refinement on Removal of Tin Tetraphenyl Scavengers from Transformer Askarel DSV| 356910 STLCOPCB4085792 Chapter 10 - Page 80-93 Contamination s <i Page 80 Avoidance of Contaminating Askarel Capacitors % Page 83 Avoidance of Contaminating \ Askarel Transformers - 2 i Chapter 11 - Page 94-97 Reworking Contaminated Transformer Askarel Page 94 Page 95 Normal Conditions Arced Conditions } Chapter 12 - Page 98-IOO Dermatology and Toxicology i Page 98 Skin Exposure Page 99 Page 100 Exposure to Vapors Vapors from a Severely Arced l Askarel Transformer Attachments: Drawing No. 31-20847, The Tank Car Drawing No. 31-20848, Dome Detail Drawing No. 9C-8170-5, The Horizontal Storage Tank Drawing No. D-13362, The Vertical Storage Tank Drawing No. 90-8248, The Breather Drawing No. 9C-8278, The Varec Gauge Drawing No. 9C-8178, The Unloading Platform I 356971 STLCOPCB4085793 : Mil i THE PROPER HANDLING OF AROCLORS* .AND THEIR MIXTURES IN THE ELECTRICAL INDUSTRY i INTRODUCTION i , , ,, . ,,. -- t _ | Monsanto's Aroclors*, especially the chlorinated biphenyls 1 including types 1242, 1248, 1254 and 1260, used alone or in | combination with chlorinated benzenes, are commonly used die- a lectric materials of the askarel1 class, i Askarel is a generic name referring to liquid dielectrics ? derived from halogenated aromatic hydrocarbons possessing ^ excellent chemical and dielectric stability and fire-resistance | over the temperature ranges and operating conditions required of transformers and capacitors in the electrical industry. 3s ' ; The properties of Aroclors and their mixtures, used as dielectrics are described in detail in Chapter 7 entitled, 1 "Typical Properties". These dielectrics are manufactured under j very carefully controlled conditions in order to meet the strict and exacting electrical requirements and properties. ? [ The electrical industry's use of these fluids has been i largely in accordance with the General Electric Company's I patents and developments. 1 . ___________ ____ ____ _ \ *Aroclors - Monsanto's chlorinated biphenyls and chlorinated { polyphenyls. Registered U.S. Patent Office. i ' J 5 LF. M. Clark, "Electrical Insulation", Chem. Engg. News 25* 2977 j (19^7). I -1- DSW 356972 STLCOPCB4085794 r- _ \ i i Resulting from the wide use of these materials in the i i industry, trade names have been established to identify them by different manufacturers of electrical equipment. Listed l alphabetically the trade names include, "Chlorextol," Allis % Chalmers; "Diaclor," Sangamo Electric; "Dykanol," Cornell a. Dubilier; "Elemex," Line Materials; "Hyvol," Aerovox; "Inerteen," Westinghouse Electric; "Noflamol," Wagner Electric; and Pyranol," General Electric Company. /i The purpose of this bulletin is to assist the industry with the proper and safe handling of these dielectric materials in their operations. \ ? i i f i DSW 356973 STLCOPCB4085795 i CHAPTER 1 I i PROCEDURE FOR UNLOADING TANKCARS QF AROCLORS AND AROOLOR MIXTURES A. Description of the Cars | Aroclor and mixtures of Aroclors with chlorinated benzenes are shipped by Monsanto in two types of insulated tankcars' both of which are either aluminum lined or zinc-tin metallized. ; One type of car has heating coils inside of the tank and these are in direct contact with the product. The other, a more j widely used type of car, is a double-shell tank with heating .i coils. between the inner and outer shells. The steam coil * connections are at the bottom of the car. Both types of tank ' cars are tested for 60 pounds pressure and their steam coils are tested for 200 pounds gauge pressure. ; The cars are top-unloaded by displacement with dry air . containing 10 mg. H^O/cu. ft. maximum. i C~ There are two or three connections on the tankcar dome j depending on the type of car. Where three connections exist, I one is a two inch diameter unloading line which extends to the f. j bottom of the car, the second is a one inch diameter air inlet , connection and thethird is a two inch diameter pressure safety ; vent, which is a thin lead disc adjusted to release any pressure ! in excess of 60 pounds gauge. This safety vent is hooded for protection against dust, dirt or accidental bumping. ( j Where only two connections exist on the dome, one is the two inch diameter unloading line and the other is the safety i vent. On these cars, it is necessary to remove the safety vent ! and introduce the displacement air through that connection. DSW 356974 STLCOPCB4085796 \ I 1 *** While the tankcar drawing gives., much detail, we have been asked about the following points not given in the drawing: 1. The distance from the rail track to the top of the dome of the cars is variable. It is 13 feet and 4 inches for the 7>000 gallon cars and ranges rom 11 feet to 14 feet for the 8,000 gallon cars. 2. The steam connections are located under the center of the cars.' s 3. The steam pipe connection is usually a two inch pipe, but on some cars the pipe size is 1-1/4 inches. $ i 4. American Standard taper pipe threads are used. 1ji I **** I I i4 il !i | $i - i .. DSW 356975 STLCOPCB4085797 < 1 I I Drawing No. 31-20^48 shows in detail the dome of a tankcar i with three connections. "A" Is the two inch unloading line i which extends to a small sump at the bottom of the car. "B" f is the one inch air inlet connection. "C" is the hooded safety- vent. The car dome cover with fitted bolts is shown in the center. It is fitted with an aluminum envelope Goetze gasket. This drawing also shvB a bottom opening in the car . This can a be opened only from the inside of the car and its purpose is for cleaning operations. It has no use at all in unloading the car. Drawing No. 31-20847 shows the overall dimensions of the 8,000 gallon Aroclor tankcar. B. Procedure for Unloading the Cars The car should be spotted at an unloading dock similar to the one shown by Drawing No. 9C-8178, The car must be level and the brakes set properly. "STOP - TANKCAR CONNECTED" signs should be placed fore and aft the car to warn switching crews. 1 If it is raning or snowing or the humidity Is extremely 1 high, it is not advisable to open the car. In case the car ! must be sampled and opened during bad weather, a canvas canopy must be placed over the dome of the car. It Is preferable to t unload the cars under roof or Inside the factory. Unless it is absolutely necessary because of following described situations \ i the dome cover should not be opened until ready for sampling. The dome cover Is sealed with a standard railroad wire and a seal, and Monsanto should be notified if this seal is found I broken upon receipt of the car. DSW 356976 STLCOPCB4085798 i 8 The first step in unloading is to inspect the dome and 1 1 clean around the dome cover to remove all loose dirt, water or i snow. Wiping rags and a brush should be used to clean before the dome cover and connections are opened. Then, the screwed hood over the air-inlet valve should be removed and this valve opened fully and left open while heating S the car. A Weston or metal encased thermometer should be inserted through this air-inlet valve opening and the tempera ture of the interior of the car determined. If the car temperature is below the caution temperature shown in the following Table 1, it will be necessary to take the special step of inserting a "hair-pin" heating coil through the dome of the car to preclude rupturing the tankcar seams t during the heating period. TABLE I i Temperature C. Below A3TM Pour which Caution Must Be Product Point C. Used in Heating Aroclor 1260 + 30 +. 40 Aroclor 1254 + 10 + 20 1 Aroclor 1248 Aroclor 1242 -7 -19 +5 - 10 ! Inerteen PPO Pyranol 1467 Pre-heating is not required'" Pre-heating is not required* Pyranol 1470 Pre-heating is not required* Pyranol l48l Pre-heating is not required* i) Except if the material has cooled below -10C. and crystals of scavenger have separated. Then, 1 ii the material should be heated to 70C. (158F.) until complete solution has been accomplished. 1it DS\N 356977 STLCOPCB4085799 i i i If the dome of the car is to be opened for the pre-heating * operation, it is necessary that it be covered with a clean i canvas. Extreme care must be taken to avoid getting dirt or moisture into the car. It is due to the relatively high viscosity of some of the Aroclors at low temperatures that it becomes necessary to " form a column of molten material from top to bottom of the car, in the center, to prevent hydraulic pressure build-up which " may rupture the tank shell if there is too rapid localized heating when employing the main steam coils. When such pre-heating is required, a satisfactory vent \ hole can be made by inserting a "hair-pin" coil (1/2 inch diameter brass, galvanized, or stainless steel pipe) into the open dome of the car and introducing steam through the coil until there is a column of fluid Aroclor from top to bottom. i i After the vent hole is melted through the material to f3 the bottom of the car, the "hair-pin" coil should be removed l and the dome cover replaced and bolted. - Steam is then introduced into the main coils. It is recommended that the steam pressure be limited to 100 pounds gauge pressure, particularly when the coils are in direct contact with the Aroclor. The steam coil outlet should be trapped or throttled with a valve. It will require eight to twenty hours to bring the material to pumping temperature - depending upon weather conditions. It Is essential that the air inlet valve be open during the heat ing period in order to vent the tank. dsw356978 6I - - ii STLCOPCB4085800 j.,1 Some calculations have been made to indicate the heat requirements for an Aroclor car. Data for an 8,000 gallon car of Aroclor 1254 are: i Specific Gravity = 1.5 I Specific Heat = 0.26 Btu/lb./F. Heat requirement for heating Aroclor from 30C. (86F.) to 110C. (230F.) is: '~ 8000 x 1.5 x 8.33 x 0.26 x (230-86) = 3,774,000 Btu. For heating from 30C. (86F.) to only 75C. (l67F.), the heat required is 2,110,000 Btu. A nine horse power boiler operating at 80 psig produces 263 lbs./hr. of steam with no reused condensate. Returning condensate at 200F. will increase the steam output to 296 lbs./hr. at 80 psig. In the first case, heating to 110C., the over-all heat transfer co-efficient is assumed to be too low to utilize the i00$ capacity of the boiler. A value of 1500 for UA with an average k T of 133F. indicates that the useable steam is I 202,000 Btu/hr. or 226 lbs./hr. steam at 80 psig. In the second case the A T is lower and the entire output of the boiler is useable. Table II sums up the approximate time calculated to heat Aroclor 1254 in an 8,000 gallon car. ! * i j DSW 356979 -7- STLCOPCB4085801 ! i TABLE II Nine HP Boiler Lbs. Steam/Hr. 30-110C. 30-75C. 100$ cap. (no reused condensate) 263 -- 9 hrs 75$ cap. (no reused condensate) -- 18 hrs. 12 hrs. (86$ cap) 100$ cap. (condensate @ 200F.) 296 -- 8 hrs. 75$ cap. (condensate @ 200F.) -- 18 hrs. 11 hrs. (76$ cap) Calculations on a five horse power boiler give heating times of the following order: { Five HP Boiler Lbs. Steam/Hr. 30-H0C. 30~75C. 100$ cap. (no reused condensate) 146 28 hrs. 16 hrs. i 100$ cap. (condensate @ 200F.) 164 25 hrs. 14 hrs. ' Aroclor cars can be heated by steam (80-100 psig) to the proper i handling temperatures in a reasonable time by using a boiler source capable of producing 200,000 to 300,000 Btu/hr. The times given here i are approximate and will act as a guide until experience shows the ; exact time for this operation. 5] 8- - DSW 356980 STLCOPCB4085802 s i , I i j i i. i. 1 | f 1 ' , i i ! i j j ' | | 1 j . ,1 The proper handling temperature for the various fluids is given in the following Table III, which indicates corresponding viscosity values: TABLE III Product Handling and Pumping Temperature C. Approximate Viscosity, S.U.S. Aroclor 1260 Aroclor 1254 Aroclor 1248 95 - 130 75 - 110 50 - 85 100 - 43 100 - 42 100 - 40 Aroclor 1242 35 - 75 100 - 40 Pyranol l48l 30 - 75 100 - 40 Pyranol 1467 20 - 55* 100 - 4o Pyranol 1470 15 - 45* 100 - 40 Inerteen PP0 20 - 55 100 - 40 *If any of the scavenger is out of solution, then the material must be heated at 70C. (158F.) until it has dissolved. Selection of pumping temperatures for any dielectric not shown on this list or which may be developed in the future should be based on a viscosity of about 100 Saybolt Universal Seconds for average pumping and about 40 S.U.S. for fast pumping, When the material has been heated to pumping temperature, a one-half inch diameter pipe "cross" arrangement containing a pressure gauge, air inlet, pressure relief valve to relieve at 30 Psig, and vent connections, should be connected to the dome air inlet pipe. Then the unloading line should be connected, Rust free and clean galvanized piping or stainless steel pipe should be used for the unloading line. DSW 356981 -9- STLCOPCB4085803 3i (At this point a sample is taken as described in Chapter 4,) 3 i Dry* air is then introduced into the tankcar and pressure built i up to 15 pounds gauge. The two inch valve cock on the stand pipe l is opened and the discharge pipe observed to be sure the liquid is being unloaded. To protect the seams in the tankcar, i the pressure must not exceed 30 pounds. The car will begin to unload at about 12 pounds pressure. 5 When the car is empty, the air pressure will drop off i rapidly and air will blow out of the vent on the receiving tank. The air flow may be stopped at this point and the tankcar i J pressure released through the vent valve on the "cross" arrangement \ After inspecting the car to be sure that it has been completely < t unloaded, all connections and dome cover should be closed tightly. It is essential that the empty tankcar be sealed immediately after the car is unloaded in order to keep the car filled with dry air during return shipment. *It is essential that the displacement air used for unloading be dried thoroughly by some dehumidfying unit such as soda lime, activated alumina or similar dehydrating agent drying unit. It may be necessary to recharge the dehumidifying unit each time that a car is unloaded. For unloading a tankcar of Aroclor | within three hours, 15 standard cubic feet a minute of air at 15 pounds per square inch gauge pressure and a -100F. dew point should be supplied. If the dry air unit is to be used only for unloading tankcars, a small single tower dryer unit containing a self- contained reactivating heater is suggested. Two manufacturers of air dryers of this type are: ! i C. M. Kemp Mfg. Co., 405 E. Oliver Street, Baltimore 2, Maryland and Pittsburgh Lectrodryer Corporation, Foot of 32nd Street, Pittsburgh, Pennsylvania. i -10- DSW 356982 t STLCOPCB4085804 ! 4 i 1 As a final step, it is desired that a standard railroad isi1 wire seal be inserted through the slotted bolts of the car fittings. Steam should be released from the car i coils and all condensate removed from the coils by It blowing with air with the steam trap by-passed. All connections must be replaced as received. Adequate care should be taken in preparing and sealing the car for ! return shipment. Unloading with dry air as described is the preferred and recommended procedure because it is done with the car dome closed which avoids contamination. Dry nitrogen may be used instead of dry air. If nitrogen is used it is essential to notify us (the supplier) so that we can'take required safety precautions relative to replacing the nitrogen with air in the returned car prior to sending our men into it for cleaning. If the car is unloaded by pumping out of the top, which required opening the dome, it is most desirable that the car be set inside of a building. If this cannot be done, then a canopy or roof should be provided over the car dome, and the unloading should be done when the weather is clear. A clean centrifugal pump with minimum capacity of i 40 gpm. is suggested. It will be necessary to prime the { ! pump and only clean askarel should be used to do this. Another method for priming the pump is to use a Penberthy steam jet. No. 22A available from Penberthy Injector Co., 1242 Holden Ave., Detroit 2, Michigan. (Further pump detail s is given on page 17). i - 11 - DSW 356983 i STLCOPCB4085805 ,I i C. Drum Packaging Drum packaging is made with new and carefully inspected 55-gallon drums. These steel drums are lined with a specially selected baked phenolic coating. An example is NESCO No,, 3 lining offered by the National Enameling and Stamping Company, Long Island, New York. Contents of the drums should not be heated by direct application of flame or strip heaters. Radiant heat from steam coils or hot air in a heated room is to be preferred. The screw plug in the drum head is fitted with a metal cap as a safe guard against tampering. The drums should be stored indoors. If outdoor storage cannot be avoided, the drums should be placed in a horizontal position and covered with a tarpaulin. |- % \% I I \ r 1 DSW 356984 -12 STLCOPCB4085806 1 ? i CHAPTER 2 t- j STORAGE TANKS i A. General Description The storage tanks should be a minimum of 10,000 gallons and preferably 12,000 to 15,000 gallons capacity to accommodate i the normal 8,000 gallon tankcars. It is preferable to locate the tanks above ground where they are easily accessible for any changes or repairs. Underground location presents difficulty in this respect. i Especially in cold climates, it is preferable to locate 1 the tanks inside of a building. The tanks should be located conveniently with reference to the tankcar unloading facilities and the area where the dielectric is used. Although Aroclors are non-corrosive to metals, corrosion l or rusting of iron and steel equipment (by oxidation) may occur 5 I resulting in contamination of the products. The resistance of Aroclors to materials of construction is given in Monsanto Technical Bulletin, OP-115, entitled, "The Aroclors", Page 6. Stainless steel tanks are very satisfactory but relatively expensive. Stainless steel pipe is relatively difficult to fabricate and it is difficult to make tight leak-proof connec tions. Storage tanks may be of steel construction if properly metallized with zinc-tin or aluminum on the interior surfaces coming in contact with the Aroclors. DSW 356985 -13- STLCOPCB4085807 -, itl ! The metallizing should be done according to the following t I procedure: ; 1. Clean an area of the surface by sand-blasting, v or a similar method to give a perfectly clean and * roughened surface. The area cleaned should not be .. greater than can be completely metallized within a I few hours after cleaning. 2. If zinc-tin metallizing Is used, a coating of zinc 0.005 inches thick should be sprayed on to the - cleaned surface. This is followed immediately by a coating of tin 0.007 inches thick. . 3* Aluminum metallized surfacing should be about 0.01 * inch thick. l The detailed procedure for metallizing and cleaning is out lined as follows: , 5 a) Sand blast, b) Coat with iron, 0.005 inches thick. (The s purpose of this coating is to provide a rougher and better bond 1 for the finish coat of aluminum or the zinc-tin combination.) ; c) Apply the selected finish coat, d) Pill the tank with tap water and warm it with steam. (If an open steam line is used, I do not allow the steam to impinge directly onto the metallized , surface of the tank.) e) Drain the tank, f) Pill with cold I 1 water and drain, g) Wipe dry and clean with clean diaper cloth | or other fabric relatively free of lint, h) Heat the tank to at t leapt 100C. (212P.) to expell moist air. It would be benefi- ? cial to heat the tank, allow it to cool and pull dry air through 5 it using a dehumidfying breather In the air line, heat again s etc., until the tank is full of comparatively dry air. i) Spray j about 100 gallons of new, electrical grade Aroclor (not high in i' * '' ' '. viscosity) or electrical grade trichlorobenzene onto the Inner | walls of the tank, washing the walls thoroughly (avoid breathing ' .. , any fumes), j) Attach the circulating pump, the lines used, and | DSW 356986 -14- STLCOPCB4085808 i \ ? i the filter press fitted with dry paper and circulate the fluid * through the system and the tank. Install new dry filter paper i several times in the press during this drying and cleaning i operation. Discard the dielectric fluid used for cleaning. ' \ k) Partially fill the tank with new Aroclor dielectric and i analyze it electrically and chemically to determine whether it meets specifications. If all testB are met, then fill i the tank with the dielectric. The tanks should be insulated using, preferably, glass foam beads as supplied by Dow-Corning or Libby-Owens-Ford. The suggested thickness of the glass insulation is one inch minimum to two inches maximum. The glass insulation may be covered with tar material commonly used for weather -proofing. t s; Another type of insulation which may be used instead of the glass is 85$ Magnesia-Wool which should be covered also with the weather-proofing tar. The advantage of the glass insul ation is that it is not moisture sensitive as is the case with Magnesia-Wool. . i If the storage tank is located outdoors, it is best that f the insulation be covered with riveted or bolted tin. sheeting 'i i painted with aluminum pa.int. This type of metal surface weathers well and is cleaned easily. All piping must be galvanized and screwed fittings must be back brazed to assure tightness. All handling pipe lines must be traced with steam lines and insulation applied over the two lines in order to keep the handling lines and the material up to the desired pumping temperature. Usually a one-fourth inch copper steam line running parallel with the handling line will suffice. -15- DSW 356987 STLCOPCB4085809 Under very severe conditions of low temperatures. It would be desirable to wind the steam line around the handling line about two turns to the foot. The tanks must be provided with ample pressurized heating coil surface to supply sufficient heat to the material to bring it to the proper temperature for pumping and handling as indicated in Table III. Heating coils should be either metallized steel, or preferably steel coils which have been galvanized after fabrication. It is recommended that the steam pressure on all heating coils should not exceed 100 pounds per square inch gauge; lower pressures may be used where practicable. It is essential that all steam coils be completely free from even minute leaks since this will intro duce water into the product. The steam coils may be introduced as "hair-pin" coils through a manhole at the side and bottom of the tank, or as is most often done. Inserted through the manhole at the top of the tank and then located near the bottom. External heating coils located in the jacket of the tank may be used but this constructlon.is more expensive and less efficient than the internal coils. The storage tanks may be fitted with a stirrer, either . through the top, side, or bottom of the tank and the propeller blade should be located near the bottom of the tank. However, insertion of a stirrer through the side offers possible source of a leak and since these materials are homogeneous, it is not essential to provide such agitation for the purpose of mixing. ' oS\N356988 STLCOPCB4085810 ] ! i Adequate circulation can also be accomplished by using I i a centrifugal type pump. Gear pumps or other equipment ii where wear or chipping of metal parts may introduce contam ination should not be used. . The pumps must be of the type r designed to handle hot oil. All wetted pump parts should a Ibe either stainless steel or bronze. The centrifugal pumps I must be provided with a deep stuffing box and proper packing i. ii used, as described in Chapter 3* As examples of pumps found completely satisfactory for this service * reference is made I to Worthington Worthite pumps. Blackmer pumps. Dean Bros., Peerless and Dayton Dowd Type C pumps for handling hot oil. ! Also, a very satisfactory arrangement for mixing or circulating and pumping the fluid from the storage tank is to use a vertical sump pump such as a Taber pump. All storage tanks must be amply provided with a dehuI midifying breather such as soda lime, activated alumina, ! etc., units. This .is essential to prevent moist air from coming in contact with the dielectric. A moisture content above 35 ppm adversely affects the electrical resistivity of these products. Provision should be made to preclude possible leakage of the drier material back into the storage tank and the drier should be inspected periodically to make sure that it is open and not plugged. B. Detailed Description Drawing No. 9C-8170 shows the detailed construction of a horizontal 15,000 gallon storage tank for Aroclor and its mixtures which has been found completely satisfactory. DSW 356989 1 -17- j STLCOPCB4085811 The various nozzles on this tank are used as follows, considering them in order from left to right on the drawing: 3" nozzle Inlet for recirculation 24" nozzle For future agitator if required (not used) 3" nozzle For soda lime or calcium chloride breather connection. 36" manhole For inspection, etc. The float guage is located in the center of this manhole. 3" nozzle Not used. 24" nozzle For future agitator if required (not used) . 3" nozzle Not used. 3" nozzle Filling inlet connection. 18" x 26" Oval nozzle For sump pump 3" nozzle For thermometer well (see detail) The two 24" nozzles were originally installed for installa tion of agitators, if required. However, it has been found unnecessary to use agitators in the storage tanks, and these nozzles could be omitted. It has been'found that circulation of the fluid by the sump pump, and into the nozzle at the opposite end of the tank, for several hours gives satisfactory blending of the tank contents. For pumping the dielectric from the storage tank, a Taber Pump Company all bronze 2-1/2" x 2" vertical sump pump with monel shaft has been found to be quite satisfactory for the appli cation. 18 "" DSW 356990 STLCOPCB4085812 ,! ! I The liquid level gauge used in the storage must be gas-tight. I! The storage tanks are equipped with Vapor Recovery Systems Co.'s s "Varec", gas-tight, automatic tank gauge as shown by drawing i i No. 9C-8278. The storage tanks should be provided with an operating plat form suitable to the customer's conditions of operation. i The dehumidifying units used as breathers on the storage tanks can be constructed as shown by Drawing No. 90-8248. The upper portion of the chamber is charged with anhydrous soda lime or another drying agent. Periodic inspection of the drying agent will show the formation of a cake of damp material on top about 1 to 1-1/2 inches deep. This cake should be removed and fresh material recharged. Any suitable construction similar to that shown on Drawing No. 9C-8248 may be used for the breather units. Drawing No. D-13362 shows design detail of a 15,000 gallon t vertical storage tank. The vertical type tank would seem especi ally desirable when insufficient space is available to accomodate the horizontal type tank. DSW 356991 i -19- STLCOPCB4085813 I i1 i J CHAPTER 3 GASKETING AND PUMP PACKING i Aroclors and their mixtures soften and swell natural rubber and many of the synthetic "rubber" materials. Such i material not recommended for use include, Hycar P, Koroseal, Perbunan, Neoprene, etc. These materials are known sources of contamination. i SUGGESTED TYPES OF PACKING AND GASKETING MATERIALS iI INCLUDE: 1. For Welded Flanged Pipe Connections: Garlock Packing Co., No. 901 or No. 7021, 1/8 inch asbestos fiber sheet. A ring of thin aluminum drawn tightly at the flange connections may be used satisfactorily also. . % 2. For Pumps: Garlock No. 234, No. 431, and Cheveron No. 7050-C are satisfactory packings. Likewise, Durametallic's spiral asbestos fiber may be used. Johns-Manville and others have comparable packing materials. 3. For Valves: Garlock No. 117 braided packing or Its equivalent is suggested. 4. Other Resistant Materials: It Is Indicated that duPont's Teflon, poly tetrafluoroethylene is not attacked by hot (130C.) Aroolor and is to be recom mended as a gasket material. Dow-Corning's Silastic, Silicone 180, is very resistant to Aroclor and is suggested for gasket purposes. 5. In some cases cork impregnated under pressure with Chrysler's Cycloweld 35-9 or Armstrong Cork Co.'s 1162-J and cured at 170C. may be used as a gasket material. These are baked phenolic type coatings. 6. Pipe Thread Compounds: When necessary to use pipe thread compounds, the following should be satisfac tory if care is taken to prevent the pipe compound from getting on the Inside of the pipe. . (a) Plastic Lead Seal - manufactured by Dura- metallic Corporation --' DSW 356992 (b) Ordinary white lead rsr\ STLCOPCB4085814 i i i Usually it is not necessary to use pipe thread compounds since all screwed pipe fittings should be sealed by back brazing. 7. All new lines and fittings should be cleaned thoroughly by steaming (for two hours) and dried with air or heat. ?I jf GASKETS FOR ASKAREL CAPACITORS AND TRANSFORMERS 1. For small capacitors requiring ring seals on the terminals, properly selected Silastic (silicone) tubing is cut to make the ring gasket. 2. The most effective and trouble free seal for transformer lids or covers is to weld the cover onto the transformer shell. To remove the welded cover a weld cutting tool or bar is used. 3. Cork - Nitrile rubber composition gaskets are sometimes used to combine the desired flow limiting property of cork with the resiliency of nitrile rubber. Only fine grained cork should be used in making this composition gasket. Special gasket cementing compounds such as GE's No. 1276 or No. 880 are used to coat the gaskets to further seal them against the transformer fluid and to accomplish firm bonding to the metal surface. 4. Nitrile rubber gaskets are also used and require no adhesive to make a liquid-tight seal. Exposure of nitrile rubber gaskets to transformer askarel should be kept at a minimum and the gasket should not be compressed beyond 2/3 of the original thick l i ness . s After long time exposure to transformer askarel g fluid or its vapor, nitrile rubber is measurably deteriorated. While gaskets made of silicone or Teflon are not attacked, these materials are relatively expensive for use in large sizes. Accordingly, for the most efficient performance it is suggested that welded covers be used on askarel transformers. fs 5 5. Instruments, such as temperature gauges, etc. may I be attached to the transformer using flange con nection to pipe located below the liquid level of i the fluid in the transformer. Such flange con nections are usually not large in diameter. Accordingly, it seems practical to use Teflon or Silastic gaskets to make these seals, especially since it is known that askarel can migrate thru cork or composition cork gaskets used _+-.v>e liquid level. DSW356993 j -21- STLCOPCB4085815 i. ` Another satisfactory approach used is to machine the flange surfaces of this type connection, i Then a Spiritallic gasket made of stainless steel * ring with asbestos inter liner for resiliency can be used satisfactorily. j 6. Screwed pipe fittings on askarel transformers ' require thorough cleaning of the threads to remove t oil, grease and dirt. Then the threads are coated | with a compound such as GE`s No. 880 and then * tightened. ' i i ? i ( l DSW 356994 i -21ASTLCOPCB4085816 i at.! CHAPTER 4 i SAMPLING METHODS i 1.) The ASTM Standard Method for sampling electrical ` , insulating oils is described in ASTM Designation: D923-49- i This describes glass and metal thiefs for sampling drums, cans, and tankcars. A specially designed thief or bomb for sampling tankcars is described, also. A very good instrument of this ' J type is the stainless-steel Bacon Bomb Thief with which samples . of the liquid can be drawn from any level of the tankcar. The ASTM procedure describes sample containers, their ' cleaning and storage. Under general precautions, the ASTM mentions that, J "Samples of the fluid shall not be taken until the oil is at least as warm as the surrounding air, because cold oil may ; condense enough moisture from a humid atmosphere to affect seriously its insulation properties. (In the case of tankcar lots, on some occasions there may be no choice, as it may be j necessary to procure samples from a tankcar when the temperature is not above the surrounding air. Gn such occasions, the temperatu: : of oil and air also the humidity if possible, should be noted in i the report of test results.) It is undesirable to do any ' sampling when the relative humidity of the atmosphere exceeds | 75 percent, and samples shall never be taken in the rain . -22- DSW 356995 STLCOPCB4085817 i ft 1 Several electrical manufacturers using Aroclor dielectrics, I i switch the tankcars directly into the plant building or under roof before sampling and unloading. These precautions in handling are taken to avoid any contamination of the fluids which are manufactured under very i strict specifications. For example, the specification for lk ionizable chlorides allows no detectable amount, (less than 0.10 parts per million). Moisture may not exceed 20 to 35 l parts per million. Tankcars are cleaned and prepared under close inspection before they are filled. When filled, and analysis shows the material in the car to be satisfactory, the car is then sealed with a standard railroad wire and seal inserted through the slots of the dome fittings. Likewise, after the tankcars have been unloaded in the industry, it is requested that the dome fittings should be sealed with a railroad wire and seal. 2.) Monsanto Methods used for sampling tankcars differ ! somewhat from the ASTM procedure. The modified techniques are used because of their greater simplicity and they have been entirely satisfactory as employed over many years. A sample is never taken when it is raining or snowing, or 1 when there is any chance of contaminated atmosphere moving 3 i in the direction of the car. However, in case of an 1 emergency during inclement weather, a canopy is placed over \ X I] i \ DSW 356996 -23- STLCOPCB4085818 $ i ? 1 the car dome before sampling. J I A satisfactory sample bottle is a five pint, round \ amber glass, packer type container fitted with a 38 millimeter 1 Bakelite screw cap with an aluminum or tin cup liner. Bottles ! of this description can be purchased from the Northwestern l> Bottle Company, 31^ North Broadway, St. Louis, Missouri according to their No. A-7253* Only new bottles and caps are used. When a shipment of i. \ bottles is received, the bottles are capped immediately and stored in their receiving cartons. Prior to use, the exterior i of the bottles is wiped with a clean cloth. The simplest sampling device used is a clean stainless steel or aluminum dipper. However, this is not a generally i i preferred device because it permits sampling the car from the near surface, only. The sampling device commonly used consists of a stainless steel tube, seven feet long with one end bent into a hook, to serve as a handle and on the other end there is a stainless steel bucket with a perforated bottom. This bucket is about 5-1/A inches inside diameter and 6 inches deep to hold the five pint bottle. This bottle is held firmly by a stainless steel collar made to slide along the shaft of the sampling device. This * I collar has a clamp attachment for fixing it tightly into place where desired around the neck of the bottle. When a car is to be sampled, a new sample bottle is clamped firmly in the bucket. _ DSW 356997 i STLCOPCB4085819 All dirt is brushed and wiped away from the car dome area i using a clean rag. The car dome is opened and the cap is then removed from the sample bottle. j The sampling device is inserted into the car so that the i neck of the bottle is at least twelve to eighteen inches i below the surface of the fluid. The sample taken is dis carded as its purpose is to rinse the bottle. A portion of the sample is used to rinse the interior of the bottle cap. This procedure is repeated until a minimum of three rinses has been made; each time the sample taken is not put back into the car. These rinses should be discarded. Then the sample is taken and the cap of the bottle is screwed down tightly. When the sample has been obtained, the car dome is replaced, immediately. The exterior of the sample bottle is wiped with a clean cloth and when returned to the laboratory it is further cleaned f with a cloth dampened with pure trichlorobenzene. If the s sample is to be shipped, the cap is taped with Scotch Tape. The sampling device is also cleaned with pure trichloro benzene and is stored in a dust free, air conditioned room. 3.) Drum Sampling: A glass thief, thoroughly cleaned with pure trichlorobenzene and dried is used to sample drums. 5i i -25- tIii\ DSW 356998 I STLCOPCB4085820 -JtiU CHAPTER 5 LABORATORY ANALYSIS AND PROCEDURE FOR TREATING AROCLORS AND THEIR MIXTURES WITH EARTH A sample of the Aroclor or Aroclor mixture taken from the f Ii . tankcar, or drums, as described in Chapter 4, is analyzed in the laboratory to determine its quality in accordance with the property values given in Chapter 7 For capacitor use, usually the important properties tested are resistivity, power factor, chlorides, and moisture. For transformer use dielectric strength, resistivity, moisture and chlorides are the important properties. If the sample is out of line with the shipping specifica tions, it is indicated that the sample has become contaminated. In this case, another sample is to be taken and the properties redetermined. If still out of specifications, the sample should be given treatment with earth. Treatment of the dielectric with conditioned Attapulgus earth will bring the electrical properties to the maximum attainable values. While there is complete agreement on the benefits derived from treating with conditioned earth, there is difference of opinion on details of the method, arising from factors such as the following. No doubt, there are differences in the absorbent power of various types of diatomaceous earth with respect to removing moisture, impurities and additives such as stabilizers or scavengers from the dielectric DSW 356999 \ -26- STLCOPCB4085821 J i materials. The size of the earth particles, temperature and i i conditions of activation of the earth, the concentrations used and the temperature, the degree of agitation and time * interval at which the dielectric is given earth treatment s are all possible variables which are still being studied in e various laboratories. , The method used by Monsanto for treating the fluid with activated earth in the laboratory is: The absorbent is minus 200 mesh Attapulgus* earth acti vated just prior to use by heating in shallow trays for four hours at 400C. (752F.) or for at least twelve hours at 250C. (482F.). At least one quart of the dielectric sample is placed into a clean two liter Pyrex beaker or three necked flask. The beaker or flask should be cleaned just prior to use in a manner similar to the procedure described in Chapter 6, Method No. 11,751> "Procedure for Cleaning of Electrodes, G.E. Cell and Accessories". i The flask or beaker is fitted with a glass or stainless steel agitator.' Heat is applied using either a hot plate or a Glas-Col mantle and is controlled by a thermostat such as a Fenwal thermo switch with a stainless steel sheath. About 0.1 to 0.2$ of the activated earth, based on the f weight of the liquid is added. *Attapulgus Division, Minerals & Chemicals Corp. of America, 210 West Washington Square, Philadelphia 5> Pennsylvania -27- DSW 357000 STLCOPCB4085822 i i The more viscous dielectrics such as Aroclors 1248 and ] 1254 are heated at about 70 to 80C. (158 - 176F.) and , the less viscous materials such as Aroclor 1242 and Pyranols * 1481, 1467, and 1470 are heated at about 50 to 6oC. (122 f to 140F.). ' After heating and stirring the sample for about four j hours, it is filtered using a clean Pyrex glass suction flask s and a Buchner funnel fitted with a Whatman No. 1 or No. 3 ^ filter paper. This apparatus and the bottle into which the ; treated sample of dielectric is transferred should have been cleaned in a manner similar to the cleaning procedure desi cribed in Chapter 6. , The earth treated and "up-graded" sample is then ready ! for final analysis of its electrical properties. | l DSW 357001 -28- STLCOPCB4085823 i i i CHAPTER 6 itj TEST PROCEDURES 1 | A. General Information " The Monsanto test methods described here with the special i equipment used are some of the control tests employed to maintain fI the quality of Aroclors for dielectric use. They are suggested as a guide for test work needed to indicate the quality of the ' dielectrics used in the manufacture of electrical goods. The most significant electrical tests made on Aroclors for capacitors are: 1. Dielectric constant. 2. Power Factor. * E 3. Resistivity. For transformer use the most significant electrical tests i of Aroclor mixtures are: 1. Dielectric Strength 2. Resistivity. - I Other than electrical tests, significant measurements of quality include, moisture, chlorides, thermal and chemical stability. The following terms are defined: # Dielectric Constant: J The dielectric constant (sometimes called specific inductive capacity) of any substance is equal to the ratio of the capa citance of a condenser when that substance is used as the dielectri to the capacitance when there is a vacuum between the conductors (for all practical purposes air at ordinary pressures may be used instead of a vacuum). "29- DSW357002 ______ . STLCOPCB4085824 i i i Dielectric Strength; i Dielectric strength is the rupturing strength of an insulating material when subjected to voltage stress under i i specific conditions and expressed in kilovolts. Breakdown tk( varies with the shape of the electrodes and does not increase directly in proportion to the thickness of the dielectric. Power Factor: ~ The power factor of a dielectric is the ratio of the energy loss in the dielectric to the "apparent power" in the dielectric. Resistivity: Resistivity is electrical resistance offered to the passage of a steady current. The volume resistivity in ohms-centimeter of an oil is the ratio of the d-c potential gradient in volts l per centimeter paralleling the current flow within the sample, to the current density in amperes per square centimeter at a given instant of time and under prescribed conditions. Volume resistivity is expressed in ohm-cm. The analytical procedures described in detail include: 1. . 2. METHOD NO. 11,751, "PROCEDURE FOR CLEANING OF ELECTRODES, G.E. CELL AND ACCESSORIES." . y` METHOD NO. 11,608, "DIELECTRIC CONSTANT AND POWER FACTOR." 1 3. METHOD NO. 11,605, "DIELECTRIC STRENGTH." 4. METHOD NO. 11,607, "RESISTIVITY." I 5 5. METHOD NO. 10,126, "CORROSION AND CHEMICAL STABILITY." 6. METHOD NO. 10,118, "INORGANIC CHLORIDES." 7. METHOD NO. 10,087, "ACID NUMBER." 8. METHOD (MODIFIED) NO. 10,620, "MOISTURE (WATER)." .. DSW 357003 1 -30- STLCOPCB4085825 9. Hydrolysis Stability Test. 10. Thermal Stability Test. B. Detailed Instruction and Testing Methods. 1. METHOD NO. 11,751, "PROCEDURE FOR CLEANING OF ELECTRODES, G.E. " ` Cell and Accessories. a. The Electrode Cleaning Procedure: 1) Place the electrodes in hot electrical grade Trichlorobenzene for ten minutes. 2) Wash with unheated TCB. 3) Rinse twice with methanol and twice with tap water. 4) Place the electrodes In hot 10$ Tri Sodium Phosphate solution. Soak and heat for ten minutes. 5) Wash thoroughly with tap water. CAUTION: After Step 5 -- DO NOT TOUCH THE ELECTRODES WITH HANDS! 6) Wash with distilled water twice. 7) Dry in drying oven for at least two hours at 120C. b. The G.E. Cell Cleaning: 1) Reclean the cell before use, when more than 8 hours have elapsed since the previous cleaning. 2) Follow the procedure for the electrodes starting at Step 4. c. Cleaning of the Accessories: 1) Apply the same cleaning procedure as given for the electrodes (Steps 1 to 7) to prepare the glass spacer and beaker for next test. 2) Clean the thermometer in the same manner as the electrodes, except for Step J. 3) Place the wet thermometer (after Step 6) directly in position in the temperature Heating Unit (Modified Fisher Isotemp Oven) ~ t0 dry* DSW 357004 -31- STLCOPCB4085826 I I \ 2. METHOD NO. 11,608. "DIELECTRIC CONSTANT AND POWER FACTOR." I. Apparatus A. Oscilloscope: Heathkit Model 0-6. B. Constant Temperature Heating Units Fisher Isotemp oven. Model 13-245A, modified to include inter wall connectors. C. A. C. Generators General Radio Type 1302-A D. Amplifier and Null Detectors General Radio type 1231-B with type 1261-A power supply. E. Capacitance Bridges General Radio Co. Capacitance ' Bridge type 716-C. F. Test cells: G. E. type, concentric cylinder electrodes Catalog #1,559*663. (G.E., Pittsfield. Mass. Transformer Lab.) G. Class B driver transformers This is used for 60 cycle measurements to excite the bridge directly from the domestic power line. It has 50 volts output with a 4800 ohm resistor in service. H. Tuned Circuit Filters: General Radio Type 1231-P2 (400 and 1000 cycle) and 1231-P3 (60 cycle). These filters aid in obtaining a more accurate frequency for the measurements by removing harmonies, noise, hum, etc. ' ? II. Adjustment of Controls on Electrical Appartus A. On Panel No. 1 (Top Panel, Amplifier and Null Detector) a. Turn the 4-way (main power) switch on the upper right hand side to the #3 position to determine the Dielectric Constant at 1000 cycles. Turn this switch to the #2 position for measurements at bO cycles. b. Allow the equipment to warm up 10 minutes. sI c. Turn "GAIN CONTROL" to 6. d. Depress "INPUT 0.03V." button. f B. On Panel No. 2 (Oscilloscope) i a. Turn "INTEN." to about the 12 o'clock position. 5f i CAUTION: Do not allow a high intensity spot i to remain stationary on the screen f for any length of time. e -32- DSW 357005 STLCOPCB4085827 i i b. Using "HOR. POSITION" and "VERT. POSITION" controls center the image on the screen. c. Adjust "FOCUS" for sharp line. d. Turn "FREQ. SELECTOR" to LOOKC. 5 1 e. Turn "FREQ. VERNIER" to 80. . | f. Turn "VERTICAL GAIN" to 5. i: g. Turn "VERTICAL INPUT" to "TO VOLT MAX.". i h. Turn "HORIZONTAL GAIN" to about 20. l , i. Turn "SYNCHORONIZING" to + 20. i j. Turn "SYN." to "EXT. SYN." 5 k. Turn "GEN." to "SWEEP GEN." i C. On Panel No. 3 (Capacitance Bridge) t a. Turn "RANGE SELECTOR" switch to "100 C" for 60 cycle measurements and to "1 KC" for 1000 cycle measurements. 5 41 i b. Turn "METHOD SWITCH" to direct. e. Turn "DISSIPATION FACTOR" selector switch t to "C)". i K D. On Panel No. 4 (oscillator) 1 a. Disregard this panel for measurements at 60 cycles. ! b. On 1000 cycle measurements, depress the No. 10 1 "MULTIPLY BY" button. j c. Set "FREQUENCY DIAL" to 100. I. . . ` d. Turn "OUTPUT" dial so that pointer is at , the end of the arrow. * e. Depress the "UNBAL. 5000 OHMS" button. I When all of the above adjustments are made, the electrical ! apparatus is ready for measurement of Dielectric Constant and ? | Power Factor. ! -33l DSW 357006 STLCOPCB4085828 i i 1 III. Determination of Constants for the Apparatus 1. Carefully assemble the cell which has been cleaned and dried within the last 8 hours,, Refer to Method No. 11,751 for the procedure to use in cleaning the 1 cells. i 2. Place the cell assembly in the Fisher oven which has been adjusted to 25C. 1 3. Connect the back wire inside the oven to the lead on the inner cylinder of the cell and the front wire to the lead on the outer cylinder of the cell. 4. Connect the cable from the capacitance bridge to the terminals on top of the oven so that the inner wire of the cable goes to the back terminal and the outside mesh casing of the cable (the ground) i goes to the front terminal. 5. Remove the thermometer from the top of the oven before going on with the test. This is important. 6. Make all adjustments on the electrical apparatus as directed in Part I of this method. 7- Balance the bridge by rotating the "CAPACITANCE" and "DISSIPATION FACTOR" dials on Panel No. 3 until the wide vertical band on the oscilliscope is adjusted to a minimum width. 8. Record the sum of the readings on the "CAPACITANCE" dial and vernier and call this value A. 9* Remove the beaker containing the cell from the oven and fill it with C.P. benzene to a level 0.737 inches (ca. 3/4 inch) above the top of the concentric cylin ders of the cell. 10. Adjust the temperature of the benzene to 250. while stirring with a thermometer. 11. Replace the cell in the oven (at 25C.) and make 1 the same electrical connections as in Steps 3 and 4. DO NOT interchange connections. ii 12. Balance the bridge again as in Step 7. 13. Record the sum of the readings on the "CAPACITANCE" dial and vernier and call this value B. ! 14. Calculate the cell constant by the following equation: Cell Constant, K - B - A (this is usually 2/27 - TTO - - - - - - - J TM ' DSW 357007 -34- STLCOPCB4085829 is | * 15. Remove the cell from the oven and balance the , bridge as in Step 7 with the "CAPACITANCE" and j "DISSIPATION" "FACTOR" dials. 16. Record the sum of the readings on the "CAPACITANCE" ; dial and vernier and call this value F. (capacitance - l' of connecting cable.) I 17. Calculate the CELL LEAD CAPACITANCE by the following | equation. ... CELL LEAD CAPACITANCE, G = A - F - K (this is j usually 1 around - 3 mmfd.) I WHERE: r A - CAPACITANCE OF ENTIRE SYSTEM IN AIR (SYSTEM } CONSTANT) # G = CAPACITANCE OF THE CELL LEADS (CELL LEAD ; CONSTANT) F = CAPACITANCE OF CABLE ANDWIRES WHICH CONNECT i THE CELL AND CELL LEADS TO THE BRIDGE, j (CONNECTOR CONSTANT) , K - CAPACITANCE OF THE CELL ALONE (THE CELL CONSTANT) 1 Tabulate the system Constant (A), the Cell Lead Constant 4 (Or), the Connector Constant (F), and the Cell Constant (K) 1 on a piece of stiff paper and post them near the instru! ment where they can be' easily referred to for comparison and calculations. !. | These constants must be checked at least once every three months and in all cases where the Dielectric 1 Constant and/or Power Factor are out of specification. t * IV. Measurement of Dielectric Constant and Power Factor on Aroclors, Pyranols, Inerteens, and Tri-Tetrachloro- \ benzene Blends. i ------------- '--------------------- A. Test Run on Cell to Determine whether it is Clean 1 and properly Aligned. 1i 1. Carefully assemble a cell which has been cleaned j and dried within the past 8 hours. * NOTE: Refer to method No. 11,751 for procedure to use in cleaning cells. f I ------------------- 1 -3o5c " DSW 357008 [ STLCOPCB4085830 i1 - \ ' iW I 1 , ; ! ; i ; . 1 r ; I j , ; 1 ' ? , \ ' l I% i i 2. Adjust the oven control to hold at a temperature of 100C. for all materials except Tri-Tetra Blends. If a Tri-Tetra blend is to be tested, adjust the oven to held a temperature of 25C. 3. Place the empty cell assembly in the oven and connect the back wire inside the oven to the lead on the inner cylinder of the cell, and connect the other (front) wire to the lead on the outer cylinder. 4. Connect the cables from the capacitance bridge to the-terminals on top of the oven so that the inner wire of the cable goes to the back terminal and the outside metal casing (ground)goes to the front terminal. . 5. Allow 15 minutes for the cell to reach temperature equilibrium inside theoven. 6. Remove the thermometer from the top of the oven before taking any measurements on the bridge. This is important. ' 7. Make all the adjustments on the electrical apparatus as directed in Part I of this method. 8. Balance the bridge by rotating the "CAPACITANCE" and "DISSIPATION FACTOR" dials on Panel No. 3 until the wide vertical band on the oscilloscope screen is adjusted to a minimum width. 9* Record the sum of the readings on the "CAPACITANCE" dial and vernier and compare this value with the SYSTEM CONSTANT determined in Part II of this method. IMPORTANT: If the value obtained in Step 9 does not agree with the System Constant A (Part II) within 5 uuf, the cell must be re-cleaned, re-dried, re-assembled, and the test run for the System Constant must be repeated. NOTE: Although the above test run must be made prior to each analysis, the value obtained In Step 9 is not to be used in calculations but is to be used only as a check on the cleanliness and alignment of the cell, - -36- DSW 357009 STLCOPCB4085831 i i B. Procedure for Testing Materials 1 I 10. Remove the cell from the oven and fill the beaker with the material to be tested to a level 0.737 Inches (ca 3/4 inch) above the cylinders of the cell. ' i 11. Adjust the temperature of the sample to 100C. (use hot plate) for all materials except Tri-Tetra blends. For Tri-Tetra blends, adjust the tempera ture of the sample to 25C. using an ice-water bath if necessary. NOTE: Stir sample continuously with a thermometer while adjusting the temperature. 12. Place the cell and sample in the oven and make the same connections from the cell to the bridge as in Steps 3 and 4. DO NOT interchange connec tions . 13. Allow 15 minutes for the cell to reach temperature equilibrium inside the oven. 14. Remove thermometer from the oven before taking a measurement. This is important. :. 15* Make the adjustment of controls on the electrical apparatus as directed in Part I of this method. 16. Balance the bridge by rotating the "CAPACITANCE" and "DISSIPATION FACTOR" dials on Panel No. 3 until the wide vertical band on the oscilloscope screen is adjusted to a minimum width. 17. Record the sum of the readings on the "CAPACITANCE" dial and vernier, and call this value X. % 18. Record the sum of the readings on the "DISSIPATION FACTOR" dial and switch. Call this value D. Calculations: Dielectric Constant - X-F-G K t j Where: X a Capacitance reading from. Step 17. si i F a Connector Constant (Determined in Part II) G = Cell Lead Constant (Determined in Part II) K s Cell Constant (Determined in Part II) -37- DSW 357010 |! STLCOPCB4085832 i i fo Power Factor f x D fo Where: f = Test Frequency (60 cycles or 1000 cycles) fQ= Frequency of "Range Selector" on Panel No.3 D = Dissipation Factor reading from Step 18. ' NOTE: When D (dissipation factor) is less than 0.1, the dissipation and power factors differ by less than 0.0005. Therefore, for our measure ments, power factors and dissipation factors are equal. Precision: (Reference: General Radio Manual for Model " 716-0 Capacitance Bridge) a. Capacitance readings are precise to + 2 mmfd. x mul tiplier reading (+ 0.2$ of full scale for each range) when the dissipation factor is less than 0.01. b. Dissipation Factor (Power Factor) readings are pre cise to + 0.0005 or + 2$ of the dial reading which ever is larger, for values less than 0.1 for D (Dissipation Factor). 3. METHOD NO. 11,605, "DIELECTRIC STRENGTH." a. Apparatus and General Information The electrical equipment necessary to provide high voltage to permit the determination of dielectric strength of liquid dielectric at commercial power frequencies is basically quite simple. The equipment assembled in the laboratory consists of a high voltage transformer of good design and with a current capacity of 2.43 KVA and with equip ment for control of the voltage and a means of measuring the voltage and to provide safety for the operator. i 38- DSW 357011 i) STLCOPCB4085833 It is enclosed in a steel gray crackle finished cabinet measuring 42" high, 22" wide, 17" deep and set on truck casters for easy mobility. Protective equipment incorporated in this apparatus prevents the application of high voltage unless all safeguards are complied with. The door on rear of cabinet must be closed. The cover over the oil must be all the way down and the voltage control must be at 0 position. Failure to comply with these requirements will prevent any action when the red button is depressed. The test cups Transformers, Voltmeters, and Accessories The askarel testing cup type No. 224809 supplied by General Electric Company is mounted on the top rear of the cabinet. It is protected by a heavy plastic cover, hinged at the rear for accessibility to the receptical. It is equipped with safety contactor so placed that the circuit energizing the high voltage contactor cannot be completed unless the protective cover is completely lowered and in place. It is impossible for the operator or anyone else to touch the testing cup when high voltage is applied,, The High Voltage Transformer manufactured by the Kelly-Koett Manufacturing Co. is of the closed core, oil immersed, shell type design. Rate @ 81,000 volt @ 40 millampers. It was recovered from a used X-ray * machine purchased quite inexpensively. DSW 357012 -3Q STLCOPCB4085834 I An auto transformer from the same X-ray machine is connected so as to limit the out-put voltage 3 of the high voltage secondary to 50,000 volts. kh i The primary of the auto transformer is connected to the secondary of a 2-1/2 KYA powerstat variable \ auto transformer supplied by the Superior Electric Company. Power to the powerstat is controlled by a 4 con tact 30 amp. solenoid circuit breaker. ' The voltmeter mounted on top near front edge is connected across the powerstat secondary and is calibrated to read directly in Kilovolts in the range of 0 - 50 K.V. The overload circuit breaker consists of a small relay connected between one side of the high \ i voltage transformer secondary center tap and ground. It is adjusted to break contact on a current drain of about 50 milliampers. The circuit for the coil of the solenoid circuit breaker is wired through the contacts of this relay. i -40 < DSW 357013 STLCOPCB4085835 I i Safety and Operating Controls .s I 1) Door interlock switch located on rear door. 2) Test cup cover interlock switch. 3) Powerstat switch mounted on rear of unit arranged so that high voltage contactor cannot be closed unless powerstat is at zero position. 4) Main power switch on front panel. 5) Powerstat voltage control on front panel. - 6) High voltage contactor push button on front panel (red). 7) Signal lamps mounted on top around voltmeter. Purpose and operation described in method of use. 5 b. Procedure 1) Ascertain that the temperature of the material under test is 25 ( 0.5)C. > NOTE: Testing at other temperature is likely to give variable results which may be misleading. I 2) Shake the sample container so as to thoroughly f mix the askarel before filling the test cup. NOTE: This operation is especially important with used Aroclor as the impurities may settle to the bottom and the test may be misleading. 3) Rinse the testing cup three times with small portions of the sample to be tested. ' 4) Immediately after final rinse, fill the cup - to a height of not less than 20 mm. (0.787 in.) above the top of the electrodes. 5) Rock the cup a few times in order that any entrapped ! air may escape. Close cover over oil test cup. 5{ 6) Allow to stand 3 minutes. CAUTION: THIS IS r IMPORTANT. i 7. Turn main toggle switch on front panel to "ON" (or up) position. Both green and amber pilot f lights on the top at either side of the voltmeter will now glow. DSW 357014 -43;- STLCOPCB4085836 ;a*>i NOTE: The green signal light is connected across the 115 volt in-put and denotes that line voltage has been applied to operating control circuit. Amber light is connected in series with sensitive switch located under high voltage contactors and connected to its armature. It indicates that high voltage contactor is in its rest position and away from contacts energizing auto transformer. 8) Turn voltage control (large knob on front) to extreme counter-clockwise position. 9) Depress red button on front. This energizes high voltage transformer and circuit breaker and is indicated by amber light going out and the red light directly over voltmeter^wiTl ligh/ET7" > 10) Watch the voltmeter and* while holding the button "IN", turn the voltage control at such speed that will cause voltage as indicated on voltmeter to rise at a rate of 3 K.V. per second. 11) Note and Record the voltmeter reading at break down. 12) Repeat the test until two successive breakdowns occur on each of two fillings of the test cup which do not differ by more than 10$. Report the average value of these two readings (Step 12) as the Dielectric Strength. If the limit of the instrument is reached before breakdown, report the Dielectric Strength as 50 K.V. at 25C. t i Cleaning of the test cup; i After the test is completed,drain the cup. ? Plush thecup with benzene. ! Then fill with Aroclor 1248 and letstand, I until the next analysis. i | -42- DSW 357015 STLCOPCB4085837 i. i \ i 5 - i ! ! s 4 f I 5 i I l \ s 1 NOTE: An exception, when samples of oil from the plant are brought yin for test, the cup must be thoroughly c.l.e..a...n..ed" with benzene and carbon tetrachloride before and after running the test The electrodes: The testing cup has two electrodes. Both electrodes are movable and have twenty threads to the inch with index notches on both the electrodes and the lock nuts. To set the Gap: Arrange one of the electrodes and the lock nuts with the index marks in line. Move the other elec trode until it comes in firm contact with the first electrode and lock it. Now unscrew the electrode with the index marks in line (Step l) two complete turns and lock it. This will leave a gap of 0.1 inch between faces of the electrodes. Cleaning of the electrodes and the test cup free of carbon coating: The following ASTM method of cleaning shall be followed when it is apparent from visual inspection . that the electrode discs of the cup are coated with carbon. Wipe clean with, dry calendered tissue paper the electrodes and the test cup. -43- DS\W 357016 STLCOPCB4085838 CAUTION: It is important to avoid touching the | electrodes with the finger or with portion of the tissue paper which has been in contact with hands. * Rinse the electrodes and cup with dry lead-free gaso- I line, Stoddard Solvent (or dry, waterwhite Kerosene) l" until they are entirely clean. Care should be taken 1 not to touch the electrodes or the inside of the cup after cleaning so as to avoid possible contamination. * 4. METHOD NO. 11,607, "RESISTIVITY." 5 a. Apparatus: i General Radio Company Megohm Bridge Type 544-B. i This is a combination of Wheatstone bridge and , vacuum tube voltmeter for indicating null. The direct measurement of resistance up to 1,000,000 ;; megohms is made possible by the use of a vacuum tube detector which absorbs negligible amount of ; power. . The voltage applied to the unknown resistor is |. 1 held approximately constant, regardless of the value I of the unknown resistance. This condition is necessary to measure resistance properly, j The accuracy of the instrument in the range en- , countered in the measurement of Aroclor resis- l * tivity, 100 to 1000 megohm is + 6^. i -44- DSW 357017 STLCOPCB4085839 I i 5 i The instrument is equipped with a 115 volt AC power supply which supplies all operating voltages for the bridge indicating circuits and in addition supplies 500 V DC for application to the material under test. The instrument is completely enclosed in a waxed finish shielded oak cabinet measuring 8-1/2" wide, 22-1/2" long and 8" high. Approximate weight--26 pounds. { Test Electrodes; Two concentric nickel cylinders with feet, obtained from General Electric Company. The inner electrode has outside diameter of 2,8" and a height of 325" with area of 184 sq. cm. The outer electrode has an inside diameter of 3" and a height of 325" with area of 198 sq. cm. The distance between electrodes is, therefore, 0.1" or 0.254 cm. By theory, electrode constant (K) area/length is 1i 191/0.254 or 752 where average area is 191 sq. cm. Also K - 36 x 10" x C (farads with air as dielectric) or 11.29 x C (mmfd. with air as dielectric). f Glass Plate; i i i Pyrex about 3-1/2" diameter with concentric grooves \ ii to assist in spacing electrodes. Obtained from General Electric Company. 4 i i Heating Unit; i Assembled in the laboratory and is the same unit i DSW 357018 ! -45- i STLCOPCB4085840 described in Dielectric Constant Apparatus (see Method No. 11,608; Equipment). b. Procedure: 1) Assemble the test cell. Place the recentlycleaned (within the last 8. hours--see Method No. 11,751# Step 9) electrodes in an 800 ml. beaker. 2) Measure the capacitance of the test cell (Cc) according to Method No. 11,608 (Dielectric Constant and Power Factor measurements.) 3) Fill the cell assembly until the liquid level is 3/4 inch above the top of the electrodes. 4) Heat the assembly on the hot plate to 100 (+ 0.5)C. 5) Place the assembly inside of the testing oven. 6) Attach top lead (+) on the megohm bridge to inner electrode. 7) Attach other lead to outer electrode. 8) Throw the three switches at the top of the megohm bridge to "ON" position. 9) Allow 10 minutes for assembly to reach temperature equilibrium inside the oven. DANGER: Make sure control knob is in "CHECK" position. Otherwise, painful shock will result if leads are touched. : : :" : :' 10) Bring the galvanometer pointer to zero by turn . ing the "ZERO ADJUST" knob in the direction in which the pointer of the galvanometer should move. 11) Turn the control knob to "CHARGE" position for 30 seconds. 12) Turn the control knob to "OPERATE" position and return the galvanometer pointer to zero by ad justment of the "MULTIPLY BY" switch and the megohm dial. 13) Read after 30 seconds. -46- DSW 357019 STLCOPCB4085841 t i i Calculation: ) I Resistivity* - Megohm dial reading (Step 12) x i "Multiply By" reading (Step 11) x capacitance of cell (Step 2) in mmfd. x 11.29 x 0.001. i l Report the result in units of 109 ohm-cm. *Values of resistivity are qualified by designation of temperature and voltage. These are for this test, \ 100C and 500 volts DC. NOTE: It is important that the product under test, electrodes, and beaker be at uniform temperature t for this determination. Temperature variations in different parts of the sample will cause the galva nometer zero to change constantly and give misleading results. CAUTION: Inasmuch as measurements must be made at a 5 potential of 500 volts DC a shock hazard exists in the handling of this appartus. With the control knob in the charge and operate position full voltage of the bridge (500 volts) is applied to the positive and low terminals and through the test leads to the electrodes. Do not attempt to handle the electrodes of the test leads unless the control knob is in the "CHECK" position. Possible penalty for failure to s. i observe this precaution -- Painful Shock. 5. METHOD NO. 10,126 "CORROSION AND CHEMICAL STABILITY." I i a. Apparatus: G.E. Corrosion Apparatus consists of the following: 1) A Corrosion Flask - It is a 300-ml. Pyrex flask ! "47- DSW 357020 A{ STLCOPCB4085842 .l with a ground glass 24/40 joint equipped with a 12-inch straight tube as an air cooled con \ denser. The air-condenser is painted on the outside with aluminum. ' ' 2) The Corrosion Apparatus; A transite box 32" long x d,! wide x 5" deep. The top of the box represents a split transite board with 5 holes cut to fit the flasks. The box is heated by two 300-watt, 15 volt G.E. Strip heaters with off-set terminals at one end (23.5,s overall length). The heating length of the heating element is covered by a copper strip 19-1/2" long x 4" wide x 1/4" thick. The temperature is controlled by an automatic thermostat with temperature setting indicator. b. Procedure: 1) Roll a rectangular (2" x 4") piece of aluminum foil so that it will pass through a ground glass 24/40 joint of the corrosion test flask. CAUTION: Be careful that after rolling the specimen does not touch itself at any point. 2) Wash the aluminum foil (Step 1) scrupulously with acetone, distilled water, acetone, benzene, and chloride-free ether. 3) Then place the foil on a clean watch-glass and X dry in an oven at 110C. for 30 min. After cleaning handle the specimen with tongs or forceps only. 4) Weigh accurately on an analytical balance the specimen (Step 3) at room'temperature. 5) Drop the weighed aluminum foil into the chloridefree corrosion flask of the "G.E. Corrosion Appa ratus." Rinse out flask with sample and rinse end of condenser with sample. 6) Add 200 ml. of the product under test to the aluminum foil (Step 4 and 5). V i 7) Set the corrosion flask in the corrosion test appa ratus . ! ! -48- DSW 357021 STLCOPCB4085843 j i 8) Attach a 12-inch straight-tube air-cooled condenser, the outside of which is painted with aluminum. i 9) Cover the exposed part of the flask with aluminum foil. i I. 10) Heat the flask for 6 (+0.1) hours at 210 (+ 5)C. r The temperature of the liquid in the test flask is mea i sured indirectly using a thermometer inserted through a cork stopper and into similar liquid contained in an identical flask seated adjacent to the test flask on the heating chamber. 2 11) At the end of the heating period, detach condenser from the flask before removing it from the hot platel ' 12) Remove the flask from the hot plate and cover all of the flask with aluminum foil (when the flask is not .1 on the hot plate.) 13) Without removing the aluminum foil covering of the flask, analyze the product (Step 6) remaining in the corrosion apparatus for: | a| Appearance, Color, and Condition. I b) Inorganic (Free) Chlorides--Apply Method No,10,ll8 c) Acidity (Acid Number) - Follow Method No. 10,087 i 14) With a pair of clean, straight nichrome tongs, * remove the aluminum foil specimen (Step 5)* wash , thoroughly, dry and weigh accurately on an analytical I balance in the same manner as before (Steps 2, 3 and 4). Report the corrosion as loss or gain in weight to the \ nearest 0.0001 g. and the Chemical Stability, as indicated I by the analysis of the products "After Corrosion Test", in the same way as reported for the original (as received) , material. 6. METHOD NO. 10,118, "INORGANIC CHLORIDES." a. Preparation of Standards: 1) Make a primary standard of 100.0 ppm by weighing 0.1648 g. C.P. NaCl into a chloride-free 1 liter volumetric flask. Dilute to the mark and mix thoroughly. Make a 10.0 ppm standard by diluting 100 ml. of the primary standard to 1 liter, and mixing well. For every 0.1 ppm standard, dilute to 10 ml. of the 10 ppm standard to one liter and , -49- DSW 357022 STLCOPCB4085844 ( tnix well. A 0.1 ppm beam is considered the very faintest beam perceptible to the eye between 15-45 seconds after adding the AgNG^ solution. If the t beam intensity is not visible at all* or if easily visible (too strong), discard the solutions and make new standards. i 2) Weigh 20.0 g. C.P. AgNQo into a chloride free dark bottle. Add 20 ml. C.'P. HMOo (chloride- ! free). Dilute to 200 ml. with wa^er. 3) All solutions should be freshly prepared every two weeks and stored in glass-stoppered Pyrex bottles. b. Light Source: i Employ the 2 battery Penlite flashlight, having a 3-4 mm. light aperture. New batteries must be used ! frequently in order to perceive beams properly. c. Procedure: f 1) Thoroughly rinse two separatory funnels with chloride-free wafer three or four times. Then take an aliquot from each funnel in a test tube which has been rinsed with chloride-free water. Test these aliquots for Tyndall beams by adding 3-5 drops of AgNOo and allowing 45 sec. for full beam to evolve. Absolutely no dust or chloride beam should be present. beam is present, . rinse all equipment with 1:1 HNGo and repeat Step 1). 2) When funnels are beam-free, drain out all the water except 50 ml. in one and 25 ml. in the other. Heat the water in both funnels to boiling. (Hold stopper while heating as steam may cause stopper to fail.) 3) Transfer 50 ml. of the sample from the sample bottle at a temperature of 95~100C. Into the f separatory funnel containing the 50 ml. of i boiling water. (As a precautionary measure, pour some of-the sample from the sample bottle i into a waste'beaker before adding the 50 ml. it to the funnel.) 4) Stopper the funnel and shake vigorously for at \ i least 1 minute, venting frequently through the ' stopcock. (Care must be exercised at all times to touch neither the lower part of the funnel stem nor the ground part of the stopcock.) 1 DSW 357023 ii STLCOPCB4085845 `Il1 X f I $ j j I \ . * | i : I. t : * , i > ! ' j s ( ) i | *t i l j 5) Allow the layers to separate and drain off the sample into the second funnel containing the 25 ml. of boiling water. . (As before, drain off a few ml. of the sample into a waste beaker before draining the sample into the second separatory funnel.) It may be necessary*- to heat the sample when transferring the sample to the second funnel; e.g., Aroclor 1260. 6) Repeat step 4 and allow the layers to separate. Then drain off the sample into a waste beaker. 7) Combine both water extracts in one funnel and shake thoroughly. . 8) Take approximately a io ml. aliquot of the water extract out through the bottom of the funnel into a 3/4" x 6" test tube. Again, first allow a few ml. to drain out before taking the aliquot. (The test tube used should be rinsed with chloridefree water several times before using.) 9) Add approximately an equal portion of chloridefree ether. (The ether is tested by shaking a portion of it with chloride-free water and testing for Tyndall beam at the end of 45 sec. If beam is present, wash ether several times with chloride free water until washings show no beam after adding . 3-5 drops AgNO^) 10) Shake the ether-water mixture until the emulsion In the sample disappears and the water layer is completely beam free before adding AgNO^. If emulsion is difficult to break, add sample drop wise through the ether and then shake. . 11) Add 3-5 drops of 10$ AgN03 solution and test for chloride beam for 45 sec. exactly. If no beam is present at the end of 45 seconds, report as <b.l ppm. The very faintest of beams is considered 0.1 ppm. If beam Is stronger it will be necessary to compare with standards of 0.15, 0.20 up to 1.0 ppm, adding the 3-5 drops of AgN03 and comparing at the end of 45 sec. The method is precise to the nearest 0.1 ppm. Report results to the nearest 0.1 ppm. 7. .METHOD NO. 10,087, "ACID NUMBER." a. Reagents; 1) Nitration grade benzol. DsW357024 -51- STLCOPCB4085846 i \ i 2) Anhydrous methanol. 3) A saturated solution of phenol red (phenol i sulfonphthalein) in methanol (approx. 0.1$). 4) A 0.01 N solution of KOK in methanol. ^ b. Procedure: l l) Place 100 ml. of benzol, 100 ml. of methanol and 0.3 ml. (pipette) of phenol red indicator into one of two clean dry 500 ml. Erlenmeyer flasks. . 2) Neutralize carefully with the 0.01 N KOH (to be first definite pink color.) 3) Pour the mixture back and forth between the two flasks several times. If the solution is still neutral, divide it equally between the two flasks, if not, repeat steps 2 and 3. 4) Weigh (+ 0.05 g.) into one of the flasks a 75-0 +5.0 g. sample and titrate with the 0.01 N, KOH until the sample matches the blank. c. Calculations: Acid No. (mg. KOH/gram sample) = ml. 0.01 N KOH x 0.56 Sample Weight -- Report the results to the nearest 0.001 if they are below 0,1, otherwise to the nearest 0,01. The method is precise to + 0.002 for- acid numbers below 0.01 and to +0.01 in the range of 0.1 to 0.01. \ NOTE 1: To convert mg. KOH/gram to mg. NaOH/gram, multiply by 0.715. i 8. METHOD MODIFIED NO. 10,620, "MOISTURE (WATER)". a. Introductory Comment; The Karl Fischer Reagent titration method used in ! the analytical laboratory involves use of an analyt ical balance to weigh accurately about one drop of water used in preparing the standard. Since an analytical balance may not be available, the method has been modified and uses a purchased standard water s solution as described below. Also, in the laboratory a "Dead Stop" potentiometric method for determining -52- DSW 357025 STLCOPCB4085847 the end point is often used. However, as this equipment may not be available, the procedure described below uses the visual indicator change for determining the end point. ' b. Apparatus and Reagents: 1) Karl Fischer Burett, Automatic Pyrex No. 5750, 25 ml. capacity. Ace Glass Company, Vineland, New Jersey. 2) Water Standard in Methanol. No. SO-W-2 (l ml. = 1 mg. H2O) Fisher Scientific Company, 2800 Jefferson Ave., St. Louis, Missouri. 3) Karl Fischer Reagent Solution No. SO-K-2, Fisher Scientific Company. c. Standardization of Karl Fischer Reagent Into a 500 ml. clean, dry Erlenmeyer flask, place about 100 ml. "Anhydrous" methanol (commercially available, 99*95$). Add Karl Fischer reagent to this blank until the first color change from lemon yellow. It is not necessary to read the burette at this point. Carefully pipette 50 ml. of standard water solution into the blanked methanol. Refill the Karl Fischer burette. Titrate the solution with gentle swirling to mix, until the same color is obtained as was obtained for the blank. Now read the burette . . Moisture value of K.F. reagent in terms of grams H2O per ml. = _ (Moisture value of (Ml. Standard H2O solution) standard water so lution in gm. per __________________ ______ _____________ ml. stated ml. Karl Fischer Reagent d. Solvent Mixture: Since the solubility of the different askarels varies, the following solvent mixtures are suggested: Material Anhydrous Benzene Anhydrous Methanol Pyranol 1478 Pyranol 1488 Pyranol 1467 Pyranol 1481 Pyranol 1495 All Aroclors Inerteen PPO 0 ml. 100 ml. 100 ml. 100 ml. 100 ml. 110 ml. 100 ml. 300 ml. 200 ml. 200 ml. 200 ml. 200 ml. 190 ml. 200 ml. -53- DSW 357026 STLCOPCB4085848 r- , i ii $ i ! i e. Procedure, "Visual End Point," l 1) Place 100-300 ml, of dry solvent mixture (c) in a dry 500 ml, ground glass-stoppered Erlenmeyer flask. 2) Titrate the solvent with K.F, reagent to the visual endpoint, i.e., the first change from f| the yellow to reddish orange that persists for 30 seconds. Refill the burette. 3) Using a beam balance, weigh to the nearest f 0.1 gram by difference, a sample containing 1i 0.03 to 0.06 grams H2O into the flask. 4) Stopper and shake until the sample is in solution. 5) Titrate the solution with K.F. reagent to the ii\ endpoint described in Step 2. Record the volume of K.F. reagent used. Calculation: % H20 = ml. of K.F. reagent x HpO factor x 100 Sample Weight References: Mitchell, J. and Smith, D.M., Chemical Analysis, Vol. 5, Aquametry, Interscience Publishers, Inc., New York, (1948) $ 1 lV S } i -54- DSW 357027 STLCOPCB4085849 9 "HYDROLYSIS STABILITY TEST FOR AROCLOR" Purpose To quantitatively determine the presence of unstable chlorine compounds in chlorinated biphenyls (ask&rels). Principle The method is based upon the hydrolysis of unstable chlorine . compounds in askarels by methanolic sodium hydroxide. The resulting chloride ion is determined po-centiometrically by titration with silver nitrate solution in an essentially nonaqueous medium. The.measured chloride ion, reported as parts per million in the askarel sample, is indicative of the relative stability of the askarel in a dielectric system. ' Reagents 1. Methanol (chloride free) - 5 liters of methanol are refluxed with 0.5g Analytical Reagent Grade AgNG3 for l/2 hour. The methanol is then distilled from the AgNO^, discarding the first 100 ml. to flush the apparatus. 90$ of the charge is distilled from the flask and the contents of the flask are discarded. The methanol should be checked to assure purity by titration. The chloride ion concentration should be less than 0.01 ml. of 0.005N AgNG^ per 100 ml. of methanol. 2. Sodium Hydroxide Reagent - Analytical Reagent Grade NaOH (may be obtained from Mallinokrodt Chemical Company) is used to prepare this reagent. A 0.1N solution is prepared by dissolving 4.0 grams of analytical reagent grade NaOH in 1 liter of chloride free methanol. .. 3 Sulfuric acid - Prepared by a 50:50 volumetric dilution of Analytical Reagent Grade concentrated sulfuric acid (can be obtained from Mallinokrodt Chemical Company) with chloride free (deionized or distilled) water. The acid is always poured into the water with constant stirring to prevent any dangerous build-up of heat. 4. 0.005N AgNOo and G.0025N AgNOo - Prepared by dilution of an ampoule of concentrated aqueous AgNOo. These ampoules can be obtained from Anachemica Chemical Limited, Champlain, New York. This reagent may also be prepared by dissolving 0.8495 g. of Analytical Reagent Grade AgNOo crystals (may be obtained from Mallinokrodt Chemical Company) in one liter of chloride free water containing 30 ml. of concentrated nitric acid. This solution should be standardized against a pure chloride standard. A sodium chloride crystal such as used In Infrared spectrometer cells is a good source of pure NaCl. The AgNO^ solutions should be checked (at least monthly) to assure a consistent reagent. DSW 357028 j <0 STLCOPCB4085850 Ii l 5. Acetone (chloride free) - Prepared by distillation from AgNOo as described above, for methanol and should also j- be checked by potentiometric titration to assure optimum ` purity. Normally a chloride content of less than 0.01 ml. of 0.0025N AgNO^ per 100 ml. is derived by this method. | 6. Benzene - Analytical Reagent Grade benzene should be used. This material is normally chloride free but should be I checked by potentiometric titration to be certain. Analyti| cal Reagent Grade benzene may be obtained from Mallinckrodt Chemical Co. Equipment 1. 200 ml. tall form beaker (Berzelius type). 2. Magnetic stirrer - A suitable magnetic stirrer with ring stand base can be obtained from Fisher Scientific Co. Cat. #14-511-1. This stirrer has a built-in rheostat and i should be set at full speed and operated through a variac l to adjust its speed. This will prevent heating of the stirrer during the stirring operation. 3 4I 3. Teflon magnetic stirring bar - The bar should be cylindrical in shape and of one piece molded construction, one inch long, may be obtained from Fisher Scientific Co., Cat. #9-311-9. i 4. Microburet graduated in 0.01 ml. divisions - A suitable f buret may be obtained from Scientific Glass Apparatus Co., i Inc. Bloomfield, New Jersey Cat. #JM-570. 5. Silver electrode - The Beckman silver billet electrode Cat #39261 is the preferred type. 6. Glass electrode - A standard glass electrode such as Beckman I electrode Cat. #40498. 7. pH meter suitable for use with glass electrode - A model GS Beckman pH meter can be used. This instrument has the expanded scale and provides greatest sensitivity to incre mental emf changes. A somewhat less sensitive but, nonethe less, useable meter such as Beckman "Zeromatic" or the Leeds Northrup line operated pH meter can be used. i 8. Water bath - An individual glass water bath 150mm in diameter I 75mm high and containing 600 ml. of water heated to 40C. + iC. is used. This glass water bath can be obtained from Corning Glass Co., Corning, N.Y. Gat. #3140. 9. Usual laboratory glassware - 25 ml. pipette, buret or pipette I graduated to deliver 0.5 ml., wash bottles for pure acetone methanol, water and a sturdy ringstand. i DSW 357029 -56- ! !> { STLCOPCB4085851 Procedure for 1242 Aroclor (1499 Pyranol) 1. Twenty five grams of askarel is weighed into a tared 200 ml. beaker to the nearest 0.01 gram on a suitable balance. 2. The magnetic stirring bar is then added to the beaker i containing the sample (without the bar touching the operators' hands). f i 3. Twenty five ml. 0.1N NaOH (methanolic) is added by means of a 25 ml. pipette and the beaker is covered with a watch glass. 4. The sample beaker is immersed to a depth of 1 1/4 inches in the 40 + 1C. water bath on a magnetic stirrer and clamped securely to a firm support. The sample is stirred at as fast a speed as possible, without pronounced splashing, for 1 houf. The water bath is not heated. No effort is made to maintain the temperature at 4oC., and it will drift toward equilibrium with room temperature. 5. After the 1 hour stir, the sample beaker is removed from the bath, 0.5 ml. of dilute sulfuric acid is added to the sample by means of a suitable pipette or buret. 125 ml. of chloride free acetone is then added (a graduated cylinder is suitable for this purpose). 6. The sample is then titrated with 0.005N AgNO^ solution using the silver-glass electrode system. Normal samples of askarel require extremely small amounts of AgNOo, for this reason the titration is run using 0.01 ml. additions and allowing sufficient time for equilibrium to be established before recording the emf change. If a change of less than lmv per 0. 01 ml. addition is observed ? for 3 or 4 .01 ml. increments. larger additions of AgNOo h$ may be used for instance .05 ml. until such a change is observed. The additions then are reduced to 0.01 ml. again i to complete the titration. The endpoint normally is defined by two 50mv changes. A normal titration would yield the following typical data. MV dMV* ML dML dMV/dML X 10"2 a 400 0 .06 0 0 * 392 8 .07 .01 8 ( 352 8 - .08 .01 8 * 341 11 .09 .01 11 321 20 .10 .01 20 c 271 . 50 .11 .01 50 1 221 50 .12 .01 50 201 20 .13 .01 20 J 285 16 .14 .01 16 i * Using the GS pH meter the change is measured in 0.2mv units and hence the meter changes observed would be 5 5 times this value (i.e. 25 units for 5mv). ------- DSW357030 -57- STLCOPCB4085852 i To calculate the change per 0.01 ml. observed/ the mv change Is divided'by the volume of AgNOg. By plotting dmv/dml vs. ml., the endpoint may be found to the nearest 0.001 ml. This gives a sensitivity of + 0.007ppm - to define the endpoint to + .01 ml. no plotting is necessary and a sensitivity of + 0.07ppm is assumed. 7. A reagent blank is run exactly as above omitting the l askarel sample. i Calculations Subtract the reagent blank from the total volume of AgNC^ and for the sample then: Reactive Chlorine (ppm) = Net Volume AgNO^XNormality AgNOgX35. 46X1C>3 :1 weight : Procedure for 1254 and 1260 Aroclors (more viscous askarels) The procedure is followed exactly as above except that under Procedure, Step 2, 5 ml. of benzene is immediately added to the askarel sample and stirring bar. The sample is heated until it dissolves in the benzene and cooled to room temperature before proceeding to Step 3* The benzene, of course, should be included in the reagent blank determination. Procedure for Micro Test The dechlorination test may also be run on 5 gram samples of askarels with a reduction in sensitivity. It is run exactly as the 25 gram test above except that the amount of reagents then used are 5-01 ml. NaOH (0.1N methanolic), 0.1 ml. 1 i for acidification, and 50 ml. of acetone to dilute the sample. 0.0025N AgN03 is used to titrate this size sample. The sensi tivity is then + 0.l8ppm rather than + 0.07ppm: given by the 25 g sample (without plotting'the endpoint). General Comments A rapid titration can be made to the nearest 0.1 ml. using the normal potential at the equivalence point or use can be made of an automatic titrator for routine control procedures. | i The sensitivity in either case should be within + 0.7ppm of the value obtained by more refined techniques with 0.005N AgNO^ and a 25 gram sample. i The usual analytical precautions should be exercised in using this test method to prevent cross contamination from other sources of halogen in the laboratory. This means that all glassware, apparatus, and the area in wElch this test is run should be analytically clean. ................................. DSW 357031 -58- STLCOPCB4085853 i .10 "THERMAL STABILITY METHOD FOR AROCLORS " | Scope l' This method measures the thermal stability (chloride content) ? of chlorinated biphenyls used primarily as dielectrics. It | is used for determining the quality of finished Aroclors. . Principle Certain impurities if present in chlorinated biphenyls will break down at elevated temperatures with the liberation of HC1. The volatile HC1 is swept out of the sample with air, absorbed in water and titrated with silver nitrate solution. The results are expressed as parts per million chloride obtained during a 16 hour thermal stability test period. Reagents 1. Acetone. No special grade is required. It must contain no titratable chlorides. 2. 1% HNO3. Dilute 1 ml. concentrated HNO3 to 100 ml. 3. 0.005 NAgNOj. 0.8495g to 1000 ml. 5 ml. 0.1 NAgNOo (if available) to 100 ml. Apparatus . 1. Pressure Regulator. Moore - Model 40 - 2 - 0-50" Water. Moore Products Co. H & Lycoming St., Philadelphia 24, Pennsylvania. 2. Thermoregulator. Cenco - 99015 - (Central Scientific Co.) 3. Relay. Ebert Micrelay SPST Std. Type. Ebert Electronics Corp., Queens Village, N.Y. (Any sensitive, reliable relay can be used). j 4. Stirring Motor. Bodine NSI-13 B-2224 1/40 HP. 1725 R.P.M. 5. Bath Fluid. Dow Corning 550. 5 gallons 1 . . I 6. Leeds & Northrup ac. operated pH Meter - Cat. No. 7.664 ?? 7. Silver wire electrode I 8. Mercurous Sulfate Reference Electrode. Modified L & N calomel reference electrode prepared as follows. Dismantle the internal element from the salt bridge tube of a standard L & N calomel reference electrode. Discard the saturated KC1 solution from the tube and clean out the mercurous ------- DSW 357032 -59- STLCOPCB4085854 M.l 1 chloride and mercury from the internal element. Clean parts thoroughly. Add sufficient new clean mercury to the internal element to make contact- with electrode wire and repack chamber of internal element with mercurous sulfate moistened with 0.5M potassium sulfate. Seal the chamber with non-absorbant cotton. Fill the salt bridge i tube with 0.5M potassium sulfate and reassemble units. J 9. Burette. 1.0 ml. microburette - Koch - Fisher Scientific Co. - 2C-110. 10. Magnetic Stirrer and glass covered stirring bar. l % 11. Glass Apparatus for Samples in Bath. See attached diagram. 12. Capillaries. Glass capillaries approximately 0.2 mm in diameter and cut to a length that permits a flow of 45 ml. per min. of air. 13. Variac. 2 KVA. 14. Air Supply. Air under 4o lb. pressure is available in our laboratories. This air is purified by passing through a scrubber bottle containing 4-0$ NaOH, an empty bottle which serves as a safety, a second bottle containing cone. H2SO4 and a trap immersed in dry ice and acetone. The purified air is connected to a glass manifold having one connection for each sample. Capillaries of the appropriate length are connected between the manifold and the outlet for each sample. In this manner a constant flow of air can be obtained on all samples by applying a constant pressure to the manifold. . 15. Heating Bath. A stainless steel bath constructed according to the specifications given In the attached diagram is used. The bath is heated by applying 85 Volts to 3-50C Watt G.E. strip heaters bolted to the bottom of the bath. One 500 Watt Immersion heater is connected to the thermostat. Dow \ Corning 550 silicone is used as the bath liquid. The tem perature is maintained at 210 + 0.2C. The bath should be placed in hood and the tests carried out in total dark ness. Two 3 X 5" stainless steel plates not shown in the sketch are placed on top of the straightening vanes in the i bottom of the bath. This provides better stirring to the ends of the bath. Twelve samples can be run In the bath at one time. It . Procedure j Weigh a 290 + 1 g. sample of Aroclor into the 300 ml. Erlenmeyer *' flask. Insert the gas inlet tube and position the flask in the 210 + 0.5C. bath. The bath fluid level should be approximately j one inch below the bottom of the ground glass joint on the flask. I Place 10 ml. distilled water in the Volhard flask absorber and attach to the receiver tube from the Erlenmeyer flask. Connect \ the purified air supply from the capillary to the inlet down tube i ------- DSW 357033 -6o- STLCOPCB4085855 I in the flask. Bubble air through the sample for 16 hours at the rate of 35 to 45 ml. per minute. (The apparatus and/or sample must be kept in the dark during the l6 hour period). Transfer the water from the absorber to a 100 ml. beaker using approximately 50 ml. acetone, and 2 drops 1% HNO3 solution and titrate with 0.005N AgNC>3 solution using a magnetic stirrer. { The titration is stopped at 75 mv. which represents the point of maximum potential change and the titration endpoint. Silver I wire and mercurous sulfate electrodes (Ag-Hg, Hg2SC>4, 0.5M K2S02| system) are used for the titration. Calculations (Total ml. 0.005 NAgN03 used) (0.6l) = ppm chloride 1 ml. 0.005 NAgN03 is equivalent to 0.0001773s chloride or 0.6l ppm. Precision and Reliability The precision of the test (standard deviation) is 0.02 ppm at the 0.5 ppm chloride level and 0.06 ppm at the 2.8 ppm level. The method as written does not necessarily quantitatively measure the total unstable chlorides present. For screening purposes a total chloride figure is not necessary. Experience has shown that there is good correlation between the chloride figures obtained by this l6 hour thermal stability test and the quality of chlorinated biphenyls. Discussion i The air supply can be checked for chloride contamination by passing the air through an empty sample flask immersed in the bath. Not more than 0.03 ml. 0.005 NAgN03 should be required to give the endpoint. The air supply can be checked for ammonia 1 by measuring the pH of the absorber solution or titrating with 0.01N HC1. The pH should be between 6 and 7. Compressed cylinder air available for breathing purposes can perhaps be f used without any purification. Experience has shown that nitrogen gives low chloride figures. This indicates that air is a neces sary part of this test and that nitrogen cannot be used as a substitute. Gum rubber tubing is used in making all connections. The apparatus is cleaned with acetone. | I* 1 i S DSW 357034 i -61- STLCOPCB4085856 CHAPTER 7 j TYPICAL PROPERTIES i -------------------------------- ------------------------ The 1200 series members of the Aroclor family are chlor t 1 inated biphenyls, and are made by chlorinating biphenyl to ! approximately the percentage of chlorine, by weight, in 4 dicated by the last two digits of the serial number. For example, Aroclor 1254 is approximately 54$ chlorine on a weight basis. Accordingly, these Aroclors are not single i or simple compounds. They are a mixture of isomeric com pounds composed predominately of the chemical compound in dicated below as being their approximate equivalent: Aroclor 1242 Trichlorobiphenyl Aroclor 1248 Tetrachlorobiphenyl t Aroclor 1254 Aroclor 1260 Pentachlorobiphenyl Hexachlorobiphenyl 1 For transformer use and some capacitor use where lower viscosity is required for better low temperature operation than offered by the above Aroclors, these products are mixed with pour point depressants, particularly trichlorobenzene i resulting in various General Electric Company Pyranols j described briefly as follows: i i Transformer Pyranol l46j* 60$ of Aroclor 1260 40$ of Elec. Grade Trichlorobenzene 0.125$ of Tin Tetraphenyl f Transformer Pyranol 1470* 45$ of Aroclor 1260 55$ of Elec. Grade Trichloro- Tetrachlorobenzene Mixture f 0.125$,of Tin Tetraphenyl i i *Use of tin tetraphenyl scavenger is subject to G.E. patents and license: Royalty arrangements should be checked before 5 ii using Pyranol 1467. Questions about license concerning the use of anthraquinone stabilizer for DC capacitors should be referred to Western Electric, 195 Broadway, N.Y.C. DSW 357035 i i -62- STLCOPCB4085857 i Transformer Inerteen PPO 60$ of Aroclor 1260 40$ of Elec. Grade Trichlorobenzene i 0.20$ Phenoxypropene oxide Capacitor Pyranol 1481 75$ of Aroclor 1254 25$ of Elec. Grade Tri chlorobenzene Detailed properties of all of these products are given in the following property lists. ti l s ii i i 5 DSW 357036 I i -63- STLCOPCB4085858 i i AROCLOR 1232 i PROPERTY TYPICAL Vise. @ 37.8C. (ASTM D88) Specific Gravity @ 25/15.5C. (ASTM D287) Color, APHA ` . Condition ` Clear Acidity, mg. KOH/g. Pour Point, C. (ASTM D97) Inorganic Chlorides, ppm. Refractive Index @ 25C. Distillation Range (ASTM D20) Corrected for stem and barometic pressure Corrosion 44-51 1.270 - 1.280 50 Max. 0.014 Max. -30 or lower 0.10 max. . 1.6200 - 1.6220 10^ - 293C. min. 50^ - 310 - 320C. 90$ - 360C. max. After heating with aluminum for six hours at 210C. + 10C. the aluminum must not be corroded either on visual or weight inspection and the Aroclor 1242 should meet the following specs: Water Content, ppm Resistivity 100C., 500 volts DC @ 0.1"gap Dielectric constant 100C. @ 1000 cycles (ASTM D924) Sulfates (ASTM-D117-31)* Fixed Chlorine content (Carius)* Dielectric Strength (KV) (ASTM D877)* Hydrolysis Stability Test Chlorides, ppm. Thermal Stability Test Chlorides, ppm. Color, APHA 100 max. Acidity, mg.KOH/g. 0.014 max. Inorg. Chlorides, ppm. 0.10 max. Condition dear 35 max. 500 x 109 Ohm-cm., min. 4.3 - 4.5 None 31.5 - 32.5 35 min. 3.0 (tentative) max. 0.5 (tentative) max. I *Not determined unless by special request. { I \ s i -64- DSW 357037 STLCOPCB4085859 AROCLOR 1242 PROPERTY TYPICAL i ---------------- 3/ Vise, at /7.8C. (ASTM d88) 82 - 92 seconds Saybolt Univer. Specific Gravity at 25/15. 5C. 1.381 - 1.392 (ASTM D287) Color, APHA 50 max. Condition Clear Acidity, mg. KOH/g. 0.01 max. Pour Pt., C. (ASTM D97) -14 or lower Inorganic Chlorides, ppm. No detectable amount Refractive Index at 25 C. 1.6240 - 1.6260 Distillation Range (ASTM D20) 100 325C. min. . Corrected for stem and 900:360$fix. max. barometric pressure Corrosion After heating with aluminum for six hours at 210C + 10C, the aluminum must not be cor roded either on visual or weight inspection and the Aroclor 1242 should meet the following specs: Color, APHA 60 max. t Acidity, mg.KOH/g. 0.01 max. Inorg.Chlorides,ppm no detectable amount Condition Clear Water Content, ppm 35 max. Resistivity 100C. 500 volts DC at 0.1" gap 500 x 109 ohm-cm., min. Dielectric Constant 100C. 4.7 - 4.9 at 1000 cycles (ASTM D924) Plash Point Cleve. Open Cup* 170 - 200C. - t Fire Point C:* None to boiling point I Sulfates (ASTM-D117-31)* None - Fixed chlorine content (Carius)* 43 + 0.500 Specific Heat at 25C.* 0.29 Evaporation at 100C for 6 hrs.* 0.40 max. Dielectric Strength (KV) 35 Min. (ASTM D877)* *Not determined unless by special request. ? Hydrolysis Stability Test ! chlorides, ppm 5 Thermal Stability Test , chlorides, ppm i' 1.0 (tentative) max. 0.40 (tentative) max. -*6 5.-' DSW 357038 STLCOPCB4085860 i AROCLOR 1248 4. PROPERTY TYPICAL i Vise, at 54.4pC. (ASTM D-88) 73 80, Sec. Saybold Universal Spec. Gravity at 65/15.5C. 1.405 - 1.415 (ASTM D-287) j 1 Color, APHA Condition 100 Max. Clear Acidity, mg. KOH/g. 0.01 max. Pour Point C. (ASTM D-97) -7 Refrac. Index at 20C. Dist. Range (ASTM D-20) 1.6285 - 1.6305 First drop 310C. min. 10# - 345C. Min. 90# - 385C. Max. Water Content, ppm. 35 Resist. 100C. 500 v D.C. at 0.1'' gap 500 x 109 Ohm-cm., min. 4 Dielectric constant, 100C. 1000 cycle 4.6 Dielectric Strength 25C.* 35 KV min. . i Flash point, (C.O.C.)* 193C. Fixed Chlorine (Garius)* 47.5 - 48.5# Specific heat at 25C.* Inorganic chlorides, ppm. 0.27 0.10 max. ]' *Not determined unless by special request. , Hydrolysis Stability Test } chlorides, ppm. 3*0 (tentative)*max. Thermal Stability Test chlorides, ppm. 0.5 (tentative) max. $s i I 1. ! 1 t !i ! I j -66- DSW 357039 \ STLCOPCB4085861 AROCLOR 1254 i PROPERTY TYPICAL . Vise, at 98.9C. (ASTM D88) ' Specific Gravity at 65/15.5C. (ASTM D287) Color, APHA Condition Acidity, mg.KOH/g. . Pour Pt. C. (ASTM D97) Inorganic Chlorides, ppm. Refractive Index at 25C. Distillation Range (ASTM D20) Corrected for stem and i Barometric Pressure Corrosion 44 - 48 sec. Saybolt Univer. 1.495 - 1.505 100 max. Clear _ 0.01 max. . 7-12 No detectable amount 1.6370-1.6390 10# 366 - 378C. 50# 371 - 383C. 90# 379 - 394C. After heating with aluminum for 6 hours at 210C. plus or minus 10C. the aluminum must not be corroded either on visual or weight inspection and the Aroclor 1254 should meet the following specs: Color, APHA 150 max. Acidity, mg.KOH/g. 0.01 max. Free Chlorides,ppm. No detec- table amount Condition Clea'r Water Content, ppm. 35 max. Resistivity 100C., 500 v D.C. at 0.1" gap 500 x 109 ohm-cm., min. Dielectric Constant, 100C. 1000 cycles 4.15 - 4.35 Dielectric Strength, 25C.* 35 KV, min. Burn Point (ASTM D92)* Higher than 350C. Sulfates (ASTM D-117-31)* None Fixed Chlorine Content (Carius)* 55+0.5# } Evaporation at 100C. for 6 hrs.* 0.4#" max. Stability* There shall be no liberation of chlorine or chlorides when the i\ material is heated at 100C. f in glass vessels in contact with X air for periods of at least one month. Ageing Characteristics* No loss in resistivity over original value on heating in air for 96 hrs. at 100C. Specific Heat at 25C.* 0.26 *Not determined unless by special request. Hydrolysis Stability Test Chlorides, ppm. Thermal Stability Test Chlorides, ppm. 3.0 (tentative)max. 0.5 (tentative)max. -67- DSW 357040 STLCOPCB4085862 f t . 1 AROCLOR 1260 PROPERTY i < 1 s Vise, at 98.9C. (ASTM D88) TYPICAL 72 - 78 Sec. Saybolt Univ. Specific Gravity at90C./15.5C. 1.555 - 1.566 (ASTM D287) Color, APHA 150 max. Condition Clear f 1 Acidity, mg.KOH/g. Pour Pt.,C.(ASTM D97) Inorganic chlorides, ppm. 0.01 max. 25 - 34 No detectable amount Refractive Index, 25C. 1.6455 - 1.6470 i Distillation Range (ASTM D20) 10fa 385 - 398C. f Corrected for stem and 50$ 390 - 4o4C. -- barometric pressure. 90$ 400 - 420C. Corrosion After heating with aluminum 4 for 6 hrs. at 210C. + 10C. the aluminum must not be cor roded either on visual or weight inspection and the Aroclor 1260 should meet the following specs; Color, APHA 150 max. Free Chiorides,ppm. No detec table amount. Acidity,mg.KOH/g. 0.01 max. Condition Clear Water content, ppm. . 35 max. Resistivity,100C. 500 volts at 0.1" gap 500 x 10^ ohm-cm., min. Dielectric Strength 50C.* 30 KV., min. Dielectric Strength 100C.* 30 KV., min. Dielectric Constant 100C. 3.6 - 3-8 at 1000 cycles* 51 Burn Pt. (ASTM D92)* Higher than 350C. Sulfates (ASTM D117-31)* None 1 Fixed chlorine content (Carius)* 60 + 0.5$ Evaporation at 100C. for 6 hrs.* 0.2$ max. Stability* There shall be no liberation of chlorine or chlorides when the material is heated at 100C. in a glass vessel in contact 1 with air for periods of at least one month. 1 Specific Heat at 25C.* 0.23 v* Not determined unless by special request. | Hydrolysis Stability Test i chlorides,ppm. Thermal Stability Test chlorides, ppm. 3.0 (tentative) max. 0.7 (tentative) max. -68f osw 357041 STLCOPCB4085863 \ * ( PYRANOL l48l i PROPERTIES TYPICAL Viscosity at 37.8C. 70 - 82 sec. Saybolt Univ. I Spec. Gravity at 15.5/15.5C. 1.525 - 1.535 Color, APHA 15.0 max. Condition Clear ! t Acidity, mg. KOH/g. 0.01 max. Pour Pt., C. -15 or lower Inorganic Chlorides, ppm. 0.10 max. Refractive Index at 25C. 1.6205 - 1.6215 Distillation Range Corrected for stem and barometric pressure. First drop 205C. min. 25$ max. Below 270C. 90$ 38O - 395C. Corrosion Test Change in Weight 0.0$ Color, APHA 200 max. Acidity, after test, mg.KOH/g. 0.01 max. Free Chlorides, ppm. 0.10 max. Condition after test Clear Water Content, ppm. 35 max. Resistivity at 100C 500 volts, DC, 0.1"gap 100 x 109 ohm-cm.,min. Dielectric Constant (100C., 1000 cycles) 4.1 - 4.6 Hydrolysis Stability Test chlorides, ppm. 3.0 (tentative) max. Thermal Stability Test chlorides, ppm. 0.5 (tentative) max. k i r * i 1 i OS\N 357042 -69t STLCOPCB4085864 I * PYRANOL 1488 PROPERTIES i I Vise, at 37.8C. Spec. Grav. at 15.5/l5*5C. Color, ABHA Acidity (Mg KOH/g) Water, ppm. Condition i Refrac. Index at 25C. Free Chloride, ppm. Pour Point, C. Resis. at 100C., 500 v D.C. 1" gap Dielectric Strength (25C.) Corrosion: Loss of Aluminum TYPICAL 54-2 Sec. Saybolt Univ. 1.560 - 1.568 150 max. .014 max. 35 max. Clear 1.6137 - 1.6147 0.10 max. ' Lower than -32C. " 100 x l09 ohm-cm min. Over 35 KV ' None Heating with aluminum for 6 hrs. at 200-220C. The Pyranol after heating should meet the following specs: Dielectric Constant at 1000 cycles at 100C.* . Distilling Range (corrected)* 1st drop Below 270C. 90$ point Burn Point (ASTM D-92)* Fixed Chlorines* Arc Formed Gases* (Oxygen-free liquid at 25C.) Color, ABHA Acidity (MgKOH/g) Free Chlorides ppm Condition 200 max. .014 max. .10 max. Clear 3.7 - 4.0 200C. min. 40$ max. 295 - 4l5C. None up to boiling point 59.1$ min. . Less than 1.0$ total com bustible gases including carbon monoxide, hydrogen, and volatile hydrocarbons. *Not determined unless by special request. t I 1 $i DSW 357043 -70- STLCOPCB4085865 Ml PYRANOL 146? ! . PROPERTIES TYPICAL 3 I Vise, at 37.8C., (ASTM D88) 54 + 2 sec. Saybolt Univ. Specific Gravity at 15.5/15*5C. (ASTM D-287) I.56O - I.568 Color, APHA 150 max. 4 Condition Clear Acidity, mg. KOH/g. 0.01 max. * if Pour Point, C. (ASTM D-97) Inorganic Chlorides, ppm. -32C. or lower 0.10 max. Refractive Index at 25C. 1.6137 - 1.6147 Distillation Range (ASTM D20) 1st drop - 200C. min. i Corrected for stem and Below 270C. - 40$ max. barometric pressure 90$ - 395 - 4l5C. ' Corrosion After heating with aluminum for 6 hrs. at 200-220C., the aluminum must not be corroded either on visual or weight in spection and the Pyranol should meet the following specs: Color, APHA Acidity, mg.KOH/g. Inorganic Chlorides ppm. Condition 200 max. 0.01 max. 5 max. Clear Water Content, ppm. 30 max. Resistivity, 100C. 500 volts, l 0.1" gap 100 x 10^ ohm-cm., min. Dielectric Strength, 25C. 35 KV., min. Dielectric Constant, 100C. 1000 cycles* 3.7 - 4.0 Tin Tetraphenyl* 0.125$ + 0.01$ by weight Burn Point, (ASTM D92)* None up to Boiling Point Fixed Chlorine* 59*1$ min. Arc Formed Gases* Less than 1.0$ (Oxygen Free Liquid at 25C.) Total combustible gases including carbon monoxide, hydrogen and volatile hydro carbons. i I *Not determined unless by special request. -71i i DSW 357044 STLCOPCB4085866 PYRANOL 1470 I I PROPERTIES TYPICAL Vise, at 37.8C. (ASTM d88) 41-45 Sec. Saybolt Univ. Spec. Gravity at 15.5/15.5 C., (ASTM D287) 1.563-1.571 s Color, APHA Condition 150 max. Clear" Acidity, mg. KOH/g. 0.01 max. Pour Pt., C., (ASTM D97) -44C., or lower Inorganic Chlorides, ppm. 0.10 max. Refractive Index at 25C. 1.6075 - 1.6085 Distillation Range (ASTM D20) Corrected for stem and barometric pressure First drop 210C., min. 35$ 240 - 256C. 55$ 290 - 330C. 65$ 385 - 400C. 95$ 395 - 4l5C. Corrosion After heating with aluminum for" 6 hrs. at 200-220C., the aluminum must not be corroded either on visual or weight inspection and the Pyranol should meet the following specs: Color, APHA 200 max. i Acidity, mg.KOH/g. 0.01 max. Inorg.Chlorides,ppm 5 max. Condition Clear Water Content, ppm. 30 max. Resistivity, 100C., 500 v., 0.1"gap 100 x* 10^ ohm-cm., min. Dielectric Strength, 25C. 35 KV., min. Dielectric Constant, 100C., I 1000 cycles* Tin Tetraphenyl* V Burn Point, (ASTM D92)* 3.8 - 4.3 0.125$ + 0.01$ by weight None up to Boiling Point Fixed Chlorine* Arc Formed Gases* 60.5+0.5 Total combustible gases in (Oxygen Free Liquid at 25C.) cluding carbon monoxide, hydro gen and volatile hydrocarbons. Electrical Stability* After heating for 96 hrs. at 100C. in a closed container, i the resistivity should not decrease more than 10$. *Not determined unless by special request. DSW 357045 STLCOPCB4085867 ! 1 t PROPERTIES INERTEEN PPO TYPICAL Vise. @ 37.8C., (ASTM D88) 54- 2 sec. Saybolt Universal Specific Gravity @ 15*5/15.5C. ! (ASTM D-287) t; Color APHA 1.560 - 1.568 150 max. Condition Clear Acidity, mg. KOH/g. 0.014 max. i Pour point, C. (ASTM D-97) -32C. or lower Inorganic Chlorides, ppm. 0.10 max. . t Refractive Index @ 25C. Distillation range (ASTM D20) 1.6137 - 1.6147 First drop - 200C. min. i Corrected for stem and Below 270C. - 40$ max. barometic pressure 90$ - 395 - 4l5C. Corrosion After heating with aluminum for 6 hours at 200 - 220C. the aluminum must not be corroded either on visual or ? weight inspection and the i askarel should meet the follow ing specs: Color, APHA 200 max. Acidity, mg.KOH/g. 0.0l4 ma Inorganic Chlorides, ppm. 2 max. i Water content, ppm. Condition 30 max. Clear Resist., 100C. 500 Volts, 0.1" gap 100 x 109 Ohm-cm., min. Dielectric Strength, 25C. 35 KV., min. Dielectric constant, 100C. 1000 cycles* 3.7 - 4.0 \ Phenoxy Propene Oxide or 0.18$ - 0.22$ by weight Glycidyl Phenyl Ether f Burn point, (ASTM D92)* None up to boiling point Fixed Chlorine* 59-1$ min. Arc formed gases* Less than 1.0$ (Oxygen free liquid @ 25C.) Total combustible gases including carbon monoxide, hydrogen and volatile hydro carbons . ! f *1 s *Not determined unless by special request. r. t X -73- DSW 357046 STLCOPCB4085868 I|I S 1\ CHAPTER 8 t i QUALITY REQUIREMENTS OF AROCLORS PRIOR TO USE IN THE ELECTRICAL INDUSTRY ! Quality as Supplied to the Electrical Industry Aroclors and their mixtures supplied to the electrical industry must meet the strict requirements specified by the i industry and given in the specifications shown in Chapter 7* The electrical qualities, such as resistivity and power factor of the materials, as supplied, are not the maximum attainable. It is impractical for the manufacturer to furnish these dielectrics to the customer at the maximum attainable qualities because even with careful packaging, sampling, shipping, and handling, these fluids may pick up traces of contaminants from "clean" tank cars, drums, pipe lines, pumps, etc. However, as supplied in accordance with the specifications, the fluids must respond readily to "up-grading" by earth treatment to arrive at the desired maximum refinement required for use by the electrical industry. Typical Electrical Quality of Aroclors Used in the Industry i Capacitor Impregnation i Table IV indicates the desirable minimum resistivity I i values of Aroclor dielectrics immediately after earth refinement I by the user when ready to impregnate capacitors. These values i are compared with the similar values of the material after the !i capacitor impregnation has been completed in a relatively clean s system. ! DSW 357047 I -74- STLCOPCB4085869 t i i\ i Dielectric TABLE IV Volume Resistivity Ohm-cm at 100C. and 500 volts DC. Prior to After impregnation impregnation % Aroclor 1254 2,500 x 10s 800 x 108 Aroclor 1242 1,500 x 108 600 x 109 Pyranol l48l 600 x 109 400 x 109 The power factor of earth refined Aroclor prior to capacitor impregnation should not exceed 0.1 percent at 100C. and 1000 cycles. Transformer Filling The minimum resistivity of transformer askarel as specified for supply to the electrical industry is 100 x 109 Ohm-cm. at 100C., 500 volts and 0.1 inch gap. While power factor is not part of the suppliers* official specification, this value for freshly made transformer askarel ranges from 0.1 to 0.3 percent at 100C. and 1000 cycles. This would be approximately 0.05 percent at 20C. and 60 cycles. In order to arrive at higher and yet practical dielectric values the transformer manufacturer needs to earth refine the t i fluids immediately prior to using. I It is reasonable to strive for a volume resistivity i value around 1,500 x 109 Ohm-cm. at 100C. and power factor values of about 0.05 percent at 20C. and 60 cycles or 2 percent i at 100c. and 60 cycles. -75- DSW 357048 STLCOPCB4085870 ! I S 5 Table V compares resistivity readings with the corres i ponding power factor values obtained on the given samples of typical transformer askarel. i , TABLE V i Volume Resistivity 108 Ohm-cm. at 100C. Power Factor 60 cy. 100C. 60 cy. 20C. 1,500 2$ 0.05$ 500 5% 0.1$ 100 15% 0.7$ 60-70 20-25$ 2.0$ When adequately earth refined to give a resistivity in the range of 500 to 1500 x 109 Ohm-cm. at 100C., sample of such transformer askarel taken after filling a newly constructed and relatively clean transformer should have a resistivity of at least 200 x 109 Ohm-cm. at 100C. and a corresponding power factor less than 12 percent at 100C. and 60 cycles. ? f * t i i'4 t _76_ DSW 357049 5 STLCOPCB4085871 i CHAPTER 9 i i EARTH REFINEMENT OF AROCLORS TO ARRIVE AT THE DESIRED ELECTRICAL QUALITIES Earth Treatment in the Laboratory Preparatory to Analysis In Chapter 5 on Page 27 the laboratory procedure ! i for preparing the test sample using 0.1 to 0.2 percent of activated earth is given. It is also stated that the absorbent is minus 200 mesh Attapulgus earth' activated Just prior to use by heating in shallow trays for four hours at 400C. (752F.) or for at least 12 hours at 250C. (482F.) Earth Treatment by the Plant Manufacturing the Askarel Earth refinement in the plant Is essentially the same as used when preparing the laboratory sample. The same amount of freshly conditioned earth (0.1 percent to 0.2 percent by weight) is added to the askarel and the mixture is agitated thoroughly and heated for about four hours. . !} The more viscous dielectrics, such as Aroclor 1248 and Aroclor 1254 are heated at about 70 to 8oC. (158 to 176F.) I and the less viscous materials such as Aroclor 1242 and Pyranols 1481, 1467 and 1470, or Inerteen PPO are heated at about 50 to 60C. (122 to 140F.) . ? After about four hours contact the earth is removed < t from the dielectric fluids using a Sparkler or Sweetland or a comparable filter press, previously fitted with filter paper liners such as supplied by Carl Schleicher & Schuel Company, Inc., Keene, New Hampshire. The paper is usually 25 mils thick 77 DSW 357050 STLCOPCB4085872 i s ! and must be dried at 100C. to remove moisture prior to use in the filter press. ft i Earth Refinement by the User ' i Capacitor Manufacturers: Capacitor manufacturers it usually use the same procedure for earth refining as employed by the manufacturer of the askarels. Because this method employs loose earth which can be thoroughly mixed into the askarel, i it is believed to be the most efficient and is certainly . known to give very good results. However, towers (cylinders) filled with relatively coarse earth through which the dielectric j fluids are pumped and recirculated have also been used by capacitor manufacturers. Transformer Manufacturers: The large manufacturers of askarel transformers usually use the same type of procedure for refinement with loose earth as employed by the manufacturer of the askarel dielectrics. Handling relatively large amounts i i of the askarel transformer fluid Justifies installing the tanks and filter presses required. This earth refining equipment is . S usually supplemented with portable cartridge type filters or a small portable platen frame type filter press. This latter ! 't equipment is then used when newly made askarel transformers are i filled with the fluid and it is necessary to clean the transformer \* 5 and the fluid by draining out the fluid pumping it through the j filter press or cartridges containing the earth and recirculating I until the desired electrical properties are attained. 1 I Likewise, smaller manufacturers of askarel transformers f can use most conveniently the portable cartridge or platen frame * I type filters. - DSW 357051 fi -78- i STLCOPCB4085873 1 I The Effect of Earth Refinement on Removal of Tin i Tetraphenyl Scavengers from the Transformer Askarel: As indicated i above, normally transformer askarels respond readily to up-grading x i by the use of 0.1 to 0.2 percent by weight of earth based on the total weight of the fluid. However, if the fluids are unusually contaminated, larger amounts of earth are required to up-grade i the dielectrics. This raises question about the selective adsorption of the scavengers by the earth treatment. It is indicated that to selectively adsorb significant amounts of the scavengers, repeated treatment with 1 percent or more of earth is required, as shown in the following table: i TABLE VI REMOVAL OP TIN-TETRAPHENYL BY REPEATED TREATMENT OF ASKAREL WITH ONE PERCENT OF EARTH Tin-tetraphenyl Content Sample After 4 treatments After 7 treatments No. Original at 90C. at goC. l Pyranol 1470 1 0.119# 0.018# 0.006# ! After 4 treatments After 6 treatments ! at 60C. at 6oC. Pyranol 1470 2 0.107# 0.021# 0.003# I I \ i -79- DSW 357052 STLCOPCB4085874 | t CHAPTER 10 Itti CONTAMINATION Askarels as supplied by the manufacturer respond readily k to earth refining resulting in a very high order of dielectric \ properties. For example, it is possible to attain volume resistivity values up to 20,000 or 30,000 x 10^ Ohm-Cm. at 100C., 500 volts, 0.1 inch gap and power factor values no more than 0.05$ at 100C. and 1000 cycles. Except for very special situations, it is not practical to refine these dielectrics to this extent. In commercial use, transfer of the fluids from one clean container to another which may result in contacting traces of conducting impurities does not allow maintaining such a high order of dielectric properties. Referring to electrical values, this accounts for the more practical order of specification values as indicated in Chapter 7 i and to which the electric industry has committed the supplier of the dielectrics. This also accounts for the desirability and need of the user of askarel dielectrics to earth refine immediately prior to use in order to arrive at the maximum and yet practical dielectric values for his given purpose. Such quality values relative to askarels for capacitors and transformer work were indicated in the * I preceding Chapter 8. t AVOIDANCE OF CONTAMINATING ASKAREL CAPACITORS 5 It is necessary, practical and economical that all steps possible be taken to avoid contaminating influences in the manu \ facture of askarel capacitors. -80- DSW 357053 STLCOPCB4085875 i Jr l f * Sometimes capacitor manufacturers strive to attain the very I high order of dielectric qualities possible for askarel as mentioned l, " above. Since it is very difficult, if not almost impossible to $ | maintain such a high order, usually capacitor manufacturers comply l with the more practical schedule attainable by normal earth ir . . * refining practices as shown in Table IV Chapter 8. : Equal care must be exercised in selecting, conditioning and ' . handling the other construction materials of the askarel capacitor. I For example, the water used in manufacturing capacitor tissue is , either distilled or deionized. Quality control of the capacitor paper requires chemical tests to characterize the fiber and its purity. Physical and electrical tests to determine moisture and power factor are essential. Acceptable dielectric loss values of f the dry and unimpregnated paper do not suffice for judging quality because in some instances after impregnation with good quality ; askarel, higher dielectric losses increasing rapidly with temperature may be obtained. I' . ' The aluminum foil used must be extremely pure and free from t' | residual traces of rolling oils or compounds. Accordingly, the , term usually applied to the foil is "dry" foil. Similar care and 4 purity requirements apply to the aluminum tabs used. I The paper and aluminum foil is wound to form the core in an 5 air conditioned room and often the machine operators are required \ to wear cotton gloves to prevent oil from the operators skin 3- ( contaminating the cores. . The steel cans or turn plate capacitor cans require thorough j cleansing and degreasing with perchloroethylene of required purity i and free of any objectionable stabilizing agents. sHm.-i_iarly_, the ] _8l- DSW 357054 STLCOPCB4085876 i capacitor impregnating equipment and chambers must be kept clean. To facilitate maintenance of cleanliness, sometimes stainless steel construction is used. However, ordinary steel equipment if is common and when "conditioned", that is to say, coated with a I thin film of clean Aroclor, this type of construction material is entirely satisfactory. To condition a new plant or clean an old one, askarel is circulated through the system, then purified by earth refining and recirculated. This process is repeated until all contaminating influences have been removed. Moisture, probably the most obvious contamlnent in askarel impregnated capacitors, increases the dielectric loss under AC voltage and decreases the capacitor life. Therefore, very efficient vacuum, as low as 5 or 10 microns, and heat carefully controlled up to 130C. are employed to expel the moisture from the capacitor cores prior to impregnation. Also to avoid moisture entering the askarel during storage, it is common practice to warm the dielectric in the storage tank to about 50C. in the presence of mild vacuum. Traces of any substances soluble in askarel and capable of 5 i ionization will have a marked adversed effect on the dielectric c' loss of the askarel or the finished capacitor. Therefore, much care is required to avoid contamination with solder flux. For example, the use of rosin core solder is known to cause contamination. When rim sealing compounds are used in the lids of small capacitors, \ \ there must be assurance that the catalyst or other ingredients used in such materials do not cause contamination. Improperly selected pipe sealing compounds used on the threads on the fittings \i for sight glasses and instruments on the storage and impregnating t! equipment are known to have caused contamination. DSW 357055 i STLCOPCB4085877 t ******* ii All these factors about contamination must be kept In mind when impregnating capacitors, especially by the chamber method but also by the manifold method. The moisture content of the paper used in the capacitor cores may easily introduce several gallons of water into the average impregnating chamber. This water is removed from the capacitors prior to impregnation -- usually by heating the chamber to T30C. in the presence of efficient vacuum, 100 microns or less. If the chamber is not made of the preferred materials of construction, slight corrosion (iron rusting) may occur and the film of askarel on the interior surface of the tank may become contaminated and introduce traces of impurities into the clean dielectric fluid entering the chamber for impregnating the capacitors. In fact, because of this possibility of contamination, in some operations the capacitors are conditioned and dried in a separate oven or chamber. Then when thoroughly dried, they are then transferred into a second chamber used only for impregnation. In the ease of relatively large sized capacitors, such as power factor correction units, a manifold with branches may be used to handle each unit individually rather than by the batch -- chamber method. The unimpregnated capacitors are placed into an oven and vacuum is applied to the individual units attached to the manifold. After the capacitors have been evacuated and dried, the askarel is introduced through the manifold and its branches. Care must be taken that moist air or contaminants do not collect in the branches through which the dielectric is introduced. ******* -82A- DSW 357056 STLCOPCB4085878 ' Care must be taken to avoid contamination with any kind of j grease, oil, packing material and "rubber" gaskets used with the (, machinery, such as pumps, etc., connected with the handling and t | impregnating facilities. . It is not practical to discuss all possible sources of f contamination and it should suffice to say that the manufacturers j of askarel capacitors need to and do exercise all known precautions to avoid contamination and should evaluate and life test represent- \ ative units before supplying the finished merchandise. AVOIDANCE OF CONTAMINATING ASKAREL TRANSFORMERS I Obviously, in the manufacture of askarel transformers it is i impractical and impossible to employ purification or refinements as required, for example, in the production of askarel power factor correction capacitors. In a transformer, heat from the dielectric losses of "slightly" contaminated askarel is negligible compared with heat generated by the transformer core. While power factor and resistivity of the transformer fluid are important, they are not as critical as is the case when similar askarels are used in capacitors. However, this does not excuse the askarel transformer manufac turer from striving to meet the practical quality requirements as *i given in Chapter 8. In order to meet these requirements, it is necessary to earth refine the transformer askarel immediately prior I i to filling the unit. After the initial fill, the fluid should be withdrawn from the transformer, circulated through an earthen filter, then pumped back into the transformer and recirculated through the i Ii filter until both the fluid and transformer are clean and show the \ desired power factor and resistivity values. -83- Dsw357057 STLCOPCB4085879 i {\ If such normal earth refinement fails to give the desired results, it will be necessary to study the quality of the materials ii of construction and look for all possible sources of contamination i in the transformer and handling equipment. . f The characteristic high dielectric strength of transformer askarel is not a good criterion of purity because with the exception Ii of being adversely affected by moisture, it is not impaired irre spective of the contamination of soluble products which give increased power factor. F. M. Clark of General Electric Company tabulated i> the following values of transformer askarel selected from hundreds of askarel samples taken from commercially operating transformers to * show lack of reduction of dielectric strength with marked increase t of power factor values. I TABLE VII DIELECTRIC STRENGTH AND POWER FACTORS OF ASKAREL IN USED TRANSFORMERS Sample Power Factor, 60 cy. at 25C., per cent Dielectric Strength at 25C. KV No. 1 1 No. 2 i No. 3 No. 4 1 No. 5 0.1 0.5 5 15 30 38 35 45 39 43 However, the need for care and proper selection of transformer 1 construction materials is emphasized in the following tabulation I which shows the marked increase of power factor resulting from 1 contamination of the askarel with synthetic rubber materials and i varnished cloth, as compared with acceptable materials of construction 4_ given in Table VIII. DSW357058 -84- STLCOPCB4085880 i TABLE VIII POWER FACTOR CONTAMINATION PRODUCED BY TRANSFORMER MATERIALS AGED IN ASKAREL AT 100C. FOR 96 HOURS I Material L Askarel Power Factor, Percent Dielectric Strength, KV ! None rt Black varnished cloth 1.0 85.0 35 42 i Copper i Press Board 5 i Manila Paper J Phenolic resin 1 Shellac 1.5 40 2.0 37 1.5 39 1.6 41 6.0 36 Iron 5.0 39 Synthetic rubber 70.0 39 ! Contaminants which cause a high power factor will of course also impair resistivity values. The following Table IX shows the degree to which acceptable and good commonly used materials of construction lower resistivity from the original high values possessed by the askarel. s i TABLE IX EFFECT OF COMMONLY USED INSULATION MATERIAIB ON THE RESISTIVITY OF TRANSFORMER ASKAREL Sample Volume Resistivity x 109 Ohm-cm. at 100C. 1. Freshly made askarel before 1s heat aging i l 2. Same as 1, after heat aging (i(1 3. After heat aging with the following materials added 2,000 1,900 f 1 a - Phenolic resin tap changer material 1,200 b - Paper 750 c - Grade A press board (tan) 500 DSW 357059 1I1 !t -85- STLCOPCB4085881 i 1 l d - Grade A press board (gray) 500 e - Grade A press board, laminated strip 400 f - Cotton wrapping 300 g - Glyptal 1276 cement, cured 48 hours at 110C. 100 i ff The procedure used to evaluate materials of construction i is simple and should be employed by all makers of askarel trans i formers . i One inch square samples of the surface of the construction i materials are immersed in one liter of good quality transformer askarel and heated for 96 hours at 100C. The increase in power i factor and reduction of resistivity of the fluid after such exposure are compared with the values of the original fluid heated similarly but in the absence of the construction materials. The following Table X gives such a comparison and illustrates \ the unacceptable properties of the varnished cambric and black binding tape. { TABLE X PROPERTY & 5 1 FRESHLY MADE TRANSFORMER ASKAREL SAME FLUID EXPOSED TO FIBER BOARD VARNISHED CAMBRI OR BLACK BINDING TAPE f PF, 100C., 1 KC 0.2.% 0.45$ 3% Resistivity,q100 C. Ohm-cm. x 10y 2,500 i 436 18 Dielectric 1 Strength at 25C. 45 KV I> 45 KV 45 KV When the askarel fluid contaminated with varnished cambric or ( the black binding tape was treated for one hour at 75C. with one ( percent by weight of attapulgus earth, the power factor and resistivity i i values were restored to those of the original fluid. .. DS\I\[ 357060 IiiI -86- STLCOPCB4085882 1 While there seem to be no reports of askarel transformers iI failing in service as a result of contamination from the use of i questionable materials of construction, as discussed above, their i l unwise use is readily detectable and leads to embarrassing question t ) about impairment of the transformer's life. _ i Such a case is illustrated by an askarel transformer giving !I i a megger reading reading as low as 3, after two years service life. The transformer had not been subjected to arcing and the dielectric strength of the askarel remained above 35 KV at 25C., or well .. within the specification of new askarel. Maintenance of high dielectric strength in the presence of contamination appears to account for the transformer not failing. The following Table XI compares the properties of freshly made askarel with the similar values of the fluid taken from the transformer after two years use and also with the same contaminated ;} fluid following refinement by earth treatment. TABLE XI COMPARISON OF PROPERTIES OF CONTAMINATED TRANSFORMER ASKAREL BEFORE AND AFTER EARTH REFINEMENT PROPERTY TYPICAL OF NEW ASKAREL SAMPLE FROM TRANSFORMER USED 2 YEARS SAME SAMPLE AFTER EARTH TREATMENT 1 HOUR WITH 1% OF EARTH PF., 100C. 60 Cycles 1 to 2% PF., 100C. 1 Kc. 0.2% Resist. 100C. Ohm-cm. x 10s 500 to 1500 150$(dissipation factor) 15$ 6 1% 0.1% 2600 Dielectric Strength 25C. Moisture ppm. 45 25 4o 80 45' 20 Acidity mg. KOH/g. 0.01 0.02 0.005 Color APHA 70 1000 -87- 275 DSW 357061 0 STLCOPCB4085883 In the above case it was determined that a varnished insula ting material used in the transformer was the source of contamination Since this continuously dissolved in the askarel, obviously, removal of the fluid, followed by earth refinement and refilling the trans former accomplished nothing. The situation pertained at the time of the initial fill persisted until the deleterious component was removed. Newly built or rebuilt transformers using acceptable materials of construction often contain undeterminable traces of impurities and "dirt" which effect power factor and resistivity, but can be removed by repeated flushing with clean askarel. The following Table XII compares the properties of the askarel sampled after the initial fill with similar values after earth refinement and "soaking" or flushing the transformer, twice with good askarel. After the "dirt" or contamination was removed from the transformer the askarel fluid remained in good condition in the unit as shown in Table XII. f TABLE XII PROPERTY SAMPLE AS AFTER 4 RECEIVED TREATMENT i \ Resistivity @ 100C. 30 x 109 2600 x 109 re Dielectric constant @ 100C. 3-9 ? 3-9 Power Factor @ 100C., 1000 Cycles 2% s * 5 \ Moisture 60 ppm. 0.21% 25 ppm. Moisture solubility in askarel at 25C. is about 110 parts per million and the specification for new askarel allows a maximum of 30 parts per million of water. Essentially, moisture-free askarel was found by Clark to have a dielectric strength of 70 KV. With increased amounts of dissolved 00 DSW 357062 STLCOPCB4085884 f J water the dielectric strength gradually decreased and appeared ii to level off at a value of about 38 KV when the water content reached 80 parts per million. i i \ Water exceeding the solubility limit in askarel has a marked ! adverse affect on the power factor and resistivity of the dielectric fluid, which m^r, however, maintain its high breakdown strength 1 even though water accumulates as a separate phase on the surface. Undissolved moisture can be removed readily from transformer askarel by warming the fluid to 70C. and blowing with dry nitrogen or by treatment with dry, conditioned earth and filtering through a press fitted with dry filter papers or through an earthen cartridge type filter. l As indicated previously, moisture must be kept out of askarel t transformers by using adequate gaskets, as described in Chapter 3, ] and preferably sealing the device with dry nitrogen over the i i askarel. tS ii Mineral oil is soluble in these fire-resistant transformer askarels and is regarded to be a contaminant. Petroleum hydro $ Ia. carbons cannot be removed from askarels and the permissable I amount may not exceed 2 percent by volume lest the fire-resistant i values of the askarel is impaired beyond acceptable limits,, ls Possible contaminants in transformer manufacture include welding and solder fluxes, oils and greases, bituminous materials, l i pipe thread lubricants, and contamination from bushing and pot ! head compounds. Paint or varnish coatings must net toxich the I i interior of the transformer shell. Adhesives or coatings applied i to gaskets must not touch the interior of the transformer. i. -89- DSW 357063 STLCOPCB4085885 .H*--.* -A*. I I ( i. All natural or synthetic rubber plastics or polymeric materials, resins, varnishes and lacquers and adhesives must be regarded as contaminants unless included in the very few acceptable classes and proved suitable by actual testing. ? It is disappointing to find an askarel transformer manufacturer i' . r exercising precautions against contamination, and employing earth i refinement, and yet inadvertently using a neoprene or other objectionable hose line to transfer the fluid economically!1 i If flexible hose needs be used, it should be a flexible stainless steel type or a "rubber" hose lined with Teflon. When using any of the following suggested suitable materials of construction, it is prudent to employ appropriate control evalua tion tests to be certain that the given material within a class regarded as acceptable will meet the requirements from a physical 5Ii and electrical standpoint. TABLE XIII I ACCEPTABLE MATERIAL FOR CONSTRUCTION OF ASKAREL TRANSFORMERS Structural Materials and Fillings f s i Metals - Commonly used metals including steel, copper, aluminum, tin and brass are suitable if clean. I i Wood - Suitable if dry and free of natural gums and resins. Paper - Suitable Press Board - Suitable Cotton - Suitable Asbestos - Suitable Glass - Suitable Ceramics - Suitable Phenol-formaldehyde resins - Suitable if adequately cured. DSW 357064 -90- STLCOPCB4085886 Melamine-formaldehyde resins - Suitable if adequately cured. Cellulose acetate - Suitable Cellulose tri-acetate - Suitable . i i Cork - Suitable i Gasketing Materials and Adhesives l i Metals - (As above) Teflon - Suitable 1 Silastic (silicone) - Suitable if adequately cured. Polyurethane - Suitable if adequately cured. Cork (fine grain and bonded with phenolic resin) - Suitable, but susceptible to penetration by askarel. Nitrile rubber - Sometimes used for gaskets - but susceptible to attack by askarel. Cork Nitrile rubber - Often used Dewaxed Orange Shellac - Suitable Epoxy - Suitable if adequately cured. Isocyanate - Suitable if adequately cured. Tapes and Wire Insulation 4 8 I Cotton - Suitable % Paper - Suitable t Asbestos - Suitable ' Glass - Suitable i Rayon - Suitable Cellulose acetate - Suitable ! Teflon - Suitable fi i Silicone - Suitable -91- DSW 357065 STLCOPCB4085887 Surface Coating for Transformer Exterior Baked Phenol-Formaldehyde - Suitable Baked Melamine-Formaldehyde - Suitable f Baked Epoxies - Suitable I Polyurethane Coatings - Suitable i: i Surface Coating for Interior of Transformer Shell to Prevent i Rusting in Storage I 25 parts Aroclor 5^-60 dissolved in 75 parts lacquer thinner. The need for clean shop practice and avoidance of contaminating influences when building askarel transformers is emphasized by the ' following information submitted by a highly qualified manufacturer to indicate the condition of askarel sampled from normally opera \ ting apparatus after a number of years service. Fluid sampled from the top and bottom of at least 25 askarel transformers operating satisfactorily in different part of the country was analyzed, comprehensively. The following general conclusions were drawn: ' 1. The residual condition of the askarel samples for the most part was satisfactory, but in a few instances excessive dirt or sediment was noted. i) 2. Moisture content ranged from 19 to 6l parts per million I with most samples between 25 and 35 ppm. This reflects a ! very good degree of dryness. i 3. Acidity values were all below 0.01 mg. NaOH/g., which corresponds with the level of freshly made askarel. !{ -92- DSW 357066 ( STLCOPCB4085888 f i 4. In most cases the free chlorides did not exceed ) i\ 0.1.ppm., the specification limit of new askarel. The highest reading was 0.15 ppm. 5- Dielectric strength values ranged from a maximum i } of 46 KV to a minimum of 28 KV which values are considred satisfactory. 6. Volume resistivity at 100C. ranged from 20 to 75 x 109 Ohm-cm. which is considered to be satisfactory and may be compared with the specification for new askarel at 100 x 109 Ohm-cm., minimum. 7. Power factor values at 100C. and 60 cycles ranged from 19 to 75 percent with most samples below 60 percent. Prom the above data considered typical and satisfactory relative to all of these askarel transformers operating in a normal manner, it is seen that under satisfactory service life the resistivity of the askarel will decrease and the power factor will Increase, as indicated, from similar values of fresh askarel. These observations emphasize the need for askarel transformer makers to: 1. Earth refine the askarel immediately prior to use in order to arrive at the highest practical electrical I. s i values from the fluid. 1 2. Avoid construction material which are a source of contamination 3. In using acceptable and satisfactorily tested construction \ \ materials - to flush the transformer to remove traces of contaminating influences and "dirt". -93- DSW357067 STLCOPCB4085889 ^.1 i CHAPTER 11 I REWORKING CONTAMINATED TRANSFORMER ASKAREL i Normal Conditions | i Askarel contaminated during manufacture of the transformer | or after years of normal service life should respond very readily i to refinement by treatment with a few tenths of a percent of dry i Fullers earth, or Attapulgus clay. This was discussed in detail in previous chapters. About askarel transformers, after years of normal service life and having continued satisfactory performance, question (difficult to answer) arises as to how high may be the power factor. Also, how low may be the volume resistivity. The case histories given in the preceding chapter seem helpful in arriving at an answer. Doble Engineering suggests to their clients that, "When used askarel is found to have a power factor of 2.0 percent or more, the cause of high power factor should be determined." (This refers to power factor measured at 20C. and 60 cycles.) Doble qualifies this suggestion stating, "if the high power factor is caused by water or other conducting matter, free chlorides or i high neutralization number, the askarel is probably an operating hazard." Also, "If the high power factor is not due to these ! causes, it is probably not an operating hazard except that when I i the power factor is quite high, it may result in excessive heating i of the device in which it is used." i i -94- DSW 357068 STLCOPCB4085890 V7 p ! Since heat resulting from power factor 'increase of the t i askarel in most any commercial transformer is negligible compared 1 with heat generated by the core of the transformer, this consideratior 1 1 does not appear important. !i If the suggestion were limited to a 2 percent power factor, it would appear low and probably subject to considerable objection. However, when stated as 2 percent or more, the intention and purpose of this suggestion justifies earnest consideration, although in absence of more knowledge, it appears that conclusive answer to . this question is not at hand. However, it should be apparent that when the power factor of the askarel is 2, or 7 percent or higher at 20C. and 60 i cycles, and volume resistivity at 100C. is 20 x 109 Ohm-cm. j i or lower, contamination is present. As it is likely that such a condition can be rectified by simple earth treatment and filtra tion, there should be little question about desirability of doing this purification work to assure the best possible perform ance of the transformer. (I <i Arced Conditions . ii It is fortunate that there seem to be very few cases of ? significantly arced transformer askarel, as it is difficult to estimate the possible success of reclaiming the fluid. Particularly, it is not easy to lower the free and also the after corrosion chloride levels within the extremely low specification limits for new askarel. i DSW 357069 STLCOPCB4085891 i i Treatment with dry earth as usually used to refine contamina i ted askarel, probably will not rectify arced askarel. Special refinement, including hydrolysis of the spent scavenger material, water extraction of excess chlorides, treatment with wet earth, special drying and finally treatment with dry earth is required. The following example is considered typical: i During routine testing of a transformer filled with askarel, a short occurred in the winding, and the arc resulted in formation it of easily seen carbon particles in the fluid. The following it shows the ineffectiveness of dry earth treatment and the need j* for wet or water treatment to reclaim a sample of this material ii in the laboratory. Passing the damaged fluid through filter paper failed to remove the carbon. The carbon was removed by filtering through i paper fitted with a one-half inch pad of Attapulgus earth. At this stage, analysis indicated the following pertinent properties S ii as compared with the specification limits: PROPERTIES OF TRANSFORMER ASKARELS Property Specification Sample Inorganic chlorides Acidity, mg. KOH/g. Moisture 0.01 ppm. max. 0.010 max. 30 ppm. max. 0.25 ppm. 0.004 75 PPm. i Then 0.2 percent by weight of Attapulgus earth was added and the mixture held at 90C. and agitated for two hours and filtered. j This reduced the water to 15 ppm., but the chlorides remained at \ 0.25 ppm. . Another portion of the original sample was treated with 0.5 percent of earth, held at 50C. and agitated for two hours and filtered. This lower temperature treatment reduced the water to only 60 ppm. and the chlorides remained at 0.25 ppm. (iI -96- DSW 357070 STLCOPCB4085892 At this stage, the electrical properties were determined and found to be well within specification limits. Property Specification Sample Resistivity @ 100C. x 109 Ohm-cm. 100 576 Power Factor @ 100C. and 1,000 Cycles ---- Dielectric Constant @ 100C. 3.8 - 4.3 4.2 The above reclaiming tests were repeated using "wet" earth which contained 15 percent moisture. Again, the chlorides remained at the original level of 0.25 ppm., well out of specification. Then a sample of the askarel was extracted with water, using 20 percent based on the weight of the dielectric fluid. This reduced the chlorides to 0.15 ppm., and a second aqueous extrac tion using 10 percent of water was required to reduce the chlorides to no detectable amount. The excess moisture was then removed by blowing with dry air and finally filtering through dry earth and filter paper. Although transformer askarel is several times as expensive as mineral oil, the material is not a high cost item. Therefore, the economies of undertaking work as described above must be weighed against the cost of new askarel. In any event a fair estimate of the reclaiming cost plus . packaging, shipment to location for the work, the cost of several analyses involved, then repackaging in new containers and cost of return freight will Indicate at least 50 percent of the cost of new askarel. Accordingly, usually the most practical expedient is to purchase new askarel to replace the arced material'. -97- DSW 357071 STLCOPCB4085893 CHAPTER 12 DERMATOLOGY AND TOXICOLOGY Skin Exposure Aroclors, or askarels, accidentally spilled on the skin do not cause an acute toxicity hazard, nor will they cause serious irritation. The materials should he washed from the skin with soap and water. Prolonged skin contact should be avoided. If work clothes become impregnated with these fluids, they should be removed and washed. When sampling tank cars, canvas gloves and safety glasses, or goggles, should be worn. No special clothing is required, but the workers' garments should be laundered at least weekly and changed, if Aroclors or askarels are spilled on the clothes. If accidental burns occur from contact with hot askarels, the burn should be treated the same as any ordinary burn. Aroclor, or askarel, adhering to the burned area need not be removed immediately unless treatment of the burn demands it in which case, soap and water, or repeated washings with a vegetable oil should be used. Accidental contact with the eyes results in painful irritation, but not permanent damage to the tissues or the sight. In event of such contact, the eyes should be flushed with a large amount of water for at least 15 minutes. The patient should then be referred to a physician who will treat with an ointment to soothe the eye. -98- DSW 357072 STLCOPCB4085894 Exposure to Vapors Vapors from hot Aroclor, or askarel, have a degree of toxicity and should not he inhaled over a prolonged period of time. Experimental work on animals indicates that the maximum safe concentrations of vapors in work rooms is in the range of 0.5 to 1.0 mg. per cubic meter of air. Harmful amounts of the materials are readily detectable by odor and irritation to the eyes. Usually, people can detect concen trations of askarels in the amount of 1.0 mg. per cubic meter of air, which is the level regarded as the safe work room limit for an 8 hour day exposure. Capacitor impregnations may be done at temperatures as high as 266F. (130C.). Following impregnation and draining the chamber, exhaust ventilation should be applied to the chamber to prevent askarel vapors entering the work room. Also, when opening a heated capacitor impregnating chamber, the workmen should wear a respirator during this short interval of exposure. If transformer askarels are used at temperatures above 125 to 150F. to fill an open transformer, exhaust ventilation should be provided in the immediate area. The many years of satisfactory and safe use of Aroclors, or askarels, by the electrical industry for impregnating capacitors and filling transformers has demonstrated the industry's ability to handle these fluids without hazard to the workmen. It is both simple and in line with "good housekeeping" and personal cleanliness to exercise the suggested precautions in all cases. on dsw357073 STLCOPCB4085895 I $ i i Vapors from a Severely Arced Askarel Transformer i r Experimental data indicate that when askarel is decomposed by an electric arc* insignificant amounts of i chlorine and phosgene gas are liberated. The gas is almost entirely hydrogen chloride, which is readily detectable by its odor and its irritating characteristics in even small amounts. Thereby, adequate warning of its ! presence is provided and significant amounts of fumes would be likely to cause a hazard only in a closed area. 5 Individuals would not voluntarily expose themselves to serious toxic levels of the hydrogen chloride gas fumes. * t I ! 1i i s i -100- DSW 357074 STLCOPCB4085896