Document RJ0V1Zokv4n1rjZNg4pkYM3Xa

FILE NAME: Goulds Pumps (GLP) DATE: 1946 Nov DOC#: GLP009 DOCUMENT DESCRIPTION: Trade Journal Article - Industrial Hygiene Importance of Dust )PY 1 0 U OF t i NOV ^ (Jet the 107 Extra Capacity in SsT m o dern "cmw PH/CO BATTRt$ Gri* anyfl Is lai SALES AND SERVICE: 915-101 Marietta Street Bldg. ATLANTA, G E O R G IA B I R M I N G H A M ST. LOUIS - Fori seven? nerty. aight, 0 fOBERi Continuous work, Philco pioneered the modern extra capacitybatjjjjpicovides 10% additional capacity with no increase in overall size. |t advantage, first made available in Philco Type XL and XVL is an outstanding feamre of the famous Philco "Thirty". .. the |jj|ith 30% longer life. For today's heavier work schedules, make sure ^Capacity you can get. Specify a modern Philco. Write for catalogs. CORPORATION, Storage Battery Division, Trenton 7, N. J. ILCO FOR 50 YEARS A LEADER IN INDUSTRIAL STORAGE BATTERY DEVELOPMENT Industrial H ygiene Im portance of Dust B y N . V. H endricks Chief Engineer Industrial Hygiene Service, Georgia Department of Public Health Nearly all types of modem industry a r e concerned with dust and its control. annual cost to industry | 0m u n c o n t r o l l e d dust fits to a staggering figure. In Incases the problem of dust is pied by management as only pance. In other plants, the lefy of certain dusts is ecojreally sound, especially where Inarticulate matter may conprecious metals or may carry le processing stock. Aside /'any nuisance or economic pfesulting from the escape of there are certain dust exres which may result in acute ih hazards. This is especial ly of dusts containing a high Image of free silica, asbestos, pier toxic materials. Where considerations are involvll'such exposures, legal aspects bt themselves. In most states ffe occupational diseases are Reusable, s p e c i f i c coverage is to those disabilities resultthe inhalation of silica Definitions $iy times true dusts are conwith fumes, smokes, mists, tfogs. In order to differen tiate between the o r i g i n of these materials, a defi nition of them is in order. DUSTS are formed by the re duction of earthy materials and are usually produced by such ope rations as crushing, grinding, buffing, etc. The particle size of dusts may vary considerably, ranging from sub-microscopic to visible. FUMES are formed by conden sation and sublimation. Chemi cally, they are metallic and are usually the oxides of such metals as zinc, and lead. The particle size is usually below one micron. Smoke comes from the burning of organic material and its par ticle size is usually less than onehalf micron. Misls and Fogs result from the condensation of water vapor on suitable nuclei, and the particle size will vary with given con ditions. General Properties As a substance is reduced in particle size, there are certain general properties of the material which are changed. On breaking up a solid into finely divided par ticles, the surface area is greatly enlarged and therefore the space occupied is greatly increased. As an example, a piece of quartz one centimeter on each side when crushed to where the particles of one micron in size will present a system containing 10" number of particles. The total surface area will be 6 square meters. If these dust particles are dispersed onto the atmosphere in such manner that the concentration will be 100 million particles per cubic foot, the space occupied by this dis persed system will be 10 thousand cubic feet. The chemical activity of a solid is considerably increased by a reduction in particle size. Thus the rate of oxidation is increased as is evidenced by occasional dis astrous dust explosions. The phe nomena of adsorption becomes more important as gases are more easily adsorbed on the surface of the smaller particle. From the standpoint of health hazards resulting from dust ex posures, the physiological proper ties of dust vary somewhat with the particle size. It is an accepted fact that with exposures to silica dust, the smaller the particle size, the greater the hazard. Physiological Response Drinker has summarized the re actions resulting from the inhala- tion of dust by classifying the re body oy inhalation is more im This is also a problem in foujj sponse into four groups. These portant mode of entry than the where the pouring of br are: same material taken by mouth. done. (a) Pneumoconiosis--The dusts This is primarily due to the fact (d) Allergy--This type r- producing this type reaction are harmful only when inhaled. The principal materials producing this type reaction are free silica and that when such materials are tak en into the body by inhalation, the major portion is taken into the blood stream, whereas, a consider is in general produced by and certain organic dusts. Common Industrial asbestos dust. On inhalation, these two materials produce specific lung pathology and from the standpoint of disability, present the most important of the dust ex posures. (b) Toxic Reaction--(As poison ing by lead, cadmium or radium) These materials produce harmful effects when taken into the body both by inhalation and ingestion. With reference to lead and its compounds which may be present in the atmosphere as particulate matter, it has been fairly well established that entrance into the able part of that taken by mouth Carbonates are usually c` is removed by certain organs of ed with either calcium or}, the body. nesium. They normally (c) Metal Fume Fevers--These conditions result from the inhala nature as calcite and m a 1 tion of finely divided fume par or as dolomite, which ticles. The importance of metal both magnesium and ealef fume fever has been brought to the carbonate. Limeston" the attention of industry by the marble c o n t a i n consid great amount of welding which amounts of these carbonaf has been an important industrial do the materials from w hr tool for the past few years. Where ment is made. burning or welding is done on sur Due to the solubility in i faces which have been galvanized, fluids, these materials are r the problem of metal fumes be ed when taken into the comes immediately important. inhalation. The presence oJ bon dioxide in such fluidsj important factor influencing FIG . 2. T H E E L E C T R O S T A T IC P R E C IP IT A T O R A S U S E D FO R C O L L E C T IN G A T M O S - solubility. The same thing ai P H E R IC SA M P LE S OF DU ST AN O FU M ES. IN SER T SH OW S RATE OF SETTLIN G OF OUST. to the presence of carbon df in water which comes into <f with these materials. In that; ence of carbon dioxide ti r bonate is converted to the soluble bicarbonate, thus ad to the ease with which it is i ed by solution. Experimental and practic servations on carbonate dus dicate that these materials aif harmful when taken into the,, by inhalation. This is pr due to the fact that they are;; ly removed due to their soluft Sulfates are common ind; materials and this general, may be illustrated by which is calcium sulfate, a common material and is used in many industrial o tions. It is generally consi that this type material is no:, ic and does not present any] ticular problem from a tjj, standpoint. f Oxides vary considerab their physiological reactio` general the nature of the r: will be dependent on the. metal from which the oxide rived. Where such met specifically toxic, as would case with arsenic or lead, cific toxic' reaction could H pected from the inhalation oxide. However, other oxi" pear to be relatively ha particularly where the me of a non-specific type. This of iron oxide. The mining results in the exposure of ft") number of men to the oxicti tnae lclu toned in lids .ctical dust'] ils arej i the ' prob ' are i solubi] indu eral gyp* a Thi is wid al op Kinside s non-t any a he rably ction. e read the tide is ! letals old be l ad, a Id be ion of oxidesj hmaer tanui his is ng of of a oxide*| (?# * , `* ' ' 5vV".'#\,A. ,, i " tf, .o . .i r. t / / < ,* >*rt ' * * ?> : *; v , ^ - t - '< - ** 7 " W g il W i WM$&> sm k KAO LIN DUST M A G N IFICA TIO N I30X. etal. However, it appears ^exposure to the dust of iron produce pathology un|ych exposure is accompanied pressure of free silica, .mining of coal results in ie to coal dust which conhigh percentage of carbon. $ ld studies of exposure to dust have been made by the ^Public Health Service and [ agencies. It has been found | ;in general, coal dust is re in the lungs only when dust contains a high perge of free silica. Although Must may be deposited in the JV of exposed individuals, the Hition resulting is usually not disabling unless silica sent. lites make up an important |' of industrial materials and ffilsed principally in the pro|pn of ceramics and similar irais. Talc, kaolin, mica, |s, .etc., are chemically silicates Itheir widespread industrial ap- |tion results in a great number Employees being exposed to ..type dust. With the excep|bf asbestos, which is a silicate, Jeneral class of materials does appear to produce a disabling ition, except in isolated cases, V taken into the body by in|ipn. ibestos is the only silicate at.-the present time which |$es a lung pathology comwith that resulting from re to? silica dust. |1 1 the dust found in indusJtobabl the most important feb silica or silicon dioxide. It & in the form of quartz, flint, ftone, and chert; and is as FIG . 4. Q U A R T Z 0 U 8 T ( S i 0 2) M A G N IF IC A T IO N I30X. sociated with many other miner als and ores. The disabling con dition resulting from the inhala tion of free silica is known as silicosis and has long been a problem with industries such as stone cutting, granite, foundry, abrasive, and the like, where sili ca is used in processing. There are relatively few industrial ope rations which might result in di rect exposure to pure silica dust. The importance of silica lies in its association with other materials. As an example, in foundry opera tions the dust generally will con tain clay and materials of a nonsilicious character, so that the ac tual percentage of free silica may be relatively low. This is also true in exposures to coal, iron oxide, and the mining of ores. When hard rock or silica is present, these dusts become important mainly due to the presence of silica rather than to the inherent properties of the parent material. Factors Influencing Hazards In evaluating the exposure to a dust there are several factors which should be taken into con sideration. The duration of ex posure is important, as it will in dicate in a general way the total amount of dust which might be expected to have entered the body. Obviously other factors enter into such an evaluation of total dusti ness, and these will be discussed later. History, of past exposure is important. This is particularly true where an individual is ex posed to silica dust. This point is of extreme importance to indystry due to the fact that a worker may have contracted silicosis under a F IG . 9. C A L C IU M C A R B O N A T E O U S T M A G N IF IC A T IO N I30X. previous employment. Where such a condition exists, the desirability of preemployment examination is obvious. The c o n c e n t r a t i o n of dust breathed is important as this, within certain limits, will deter mine the possibility of develop ment of dust diseases. Consider able research and practical obser vations have been made in the field of dust exposures to corre late clinical findings with atmos pheric concentrations. For free silica, asbestos, and some of the other materials, fairly definite standards have been established. The nature of dust is important primarily from the standpoint of free silica content. This ris par ticularly true of mixed dusts which constitute the majority of industrial exposures. The volume of air breathed enters into the picture as it directly influenc es the amount of dust which will be taken into the body. The rate of respiration or amount of air breathed in general will be de termined by the physical effort required on the particular job. Where heavy work is being done, naturally an individual will re quire more ventilation than where less physical effort is involved. Dust Measurements In addition to the factors in fluencing dust hazards, it is neces sary to make direct dust measure ments in order to obtain a true evaluation of any dust exposure. Such measurements are made by the actual collection of dust sam ples, the counting of the dust par ticles, and by the identification of the materials making up the dis- persed system. For the collection of dust samples, several instru ments may be employed. Much of the early work done on the control of silicosis in the mining areas of South Africa was carried out with the Konimeter. This instrument has been used some in this country, however, it has not met with the popularity which is enjoyed by certain other methods. From the standpoint of collecting efficiency, the electro static precipitator is probably the choice instrument, however, most of the work done on correlating atmospheric dust concentrations with medical findings has been based on samples collected and counted by the Greenburg-Smith technique. The collecting device employed is an impinger unit which samples at the rate of one cubic foot per minute. Counting by this technique is done under light field. The per centage of free silica in a dust sample is usually determined by either chemical or petrographic methods. Permissible concentrations of dust havg been established for free silica,'asbestos, and other ma terials. For both silica and asbes tos, 5 million particles per cubic foot is considered as maximum working concentration. The U. S. Public Health Service has suggest ed a procedure by which the total dust concentration in millions of particles per Cubic foot is multi plied by a percentage of free sili ca. If the resulting figure is more than 5 million particles per cubic foot, the condition is considered unsafe. If less than 5 million, the condition is considered safe. There should be considered certain limits of dustiness for any type of dust, whether it be merely a nuisance two 15-foot fans are insta value or health consideration. To which handle 500 thousand cti most industrial hygienists, 50 mil lion particles per cubic foot is the maximum atmospheric concentra tion of dust under which an em ployee should work. It should be pointed out that the only way of determining both the nature of the dust and the actual concentration is by direct sampling and similar procedures for the counting of feet per minute each. Act the material removed by these is made up principally of rather than true dust. Two electric arc furnaces operated and these are i with roof fans located immedia above the units. These fans : 60 thousand cubic feet per m* dust. each. Again, the major portio Case History the material coming from the;' furnaces is smoke rather than ,J MANY industries having prob dust, and comes from the lems of dust control recog and flux material charged in1 nize the existence of such problemfusrnaces. to varied degrees. Some take pass A problem of dust control in ive attitudes, while others apply foundry is the shakeout operate s o u n d engineering procedures This is particularly true wh which result in a real job of dust s h a k e o u t is mechanical control. Such modern engineering handled on a vibrating screen; methods are used by the Le- grate. Here, a line conveyor i Tourneau Company of Toccoa, tern is used to bring the cast-' Georgia. directly to the shakeout grate, This particular plant manufac canopy type hood is installed: tures heavy road grading equip mediately over the grate ment and its major dust problem addition to canopy, side enclo" lies in operation of a foundry for are provided which prevent"] the protection of basic steel parts. leakage. The fan serving this ' It is interesting to note that this delivers 35 thousand cubic feel?; Company considers the control of minute, which results in a dust as a part of the general over capturing velocity at the en* all production schedule and as a and discharge ports. An ex- result has its control methods inte job of dust control results on grated into general plant opera particular operation. tions. Sand conditioning in m Although there are several foundries is a dusty job. With; methods which can be used for LeTourneau Company thi$. control of dust, ventilation, both handled by means of local ex in the form of general and local ventilation and three bag typ exhaust, probably offers the most ters handling 6 thousand cut satisfactory method and it is this per minute each. Tumbling p; approach which has been used by tions for cast cleaning are also, the LeTourneau Company. For vided with local exhaust ven general ventilation in the foundry, (Continued on page 80) FIG . 6. L O C A L E X H A U S T ON T U M B L E R S FO R C A S T C L E A N IN G . FIG. 7 . B A G H O U SE A N D S A N D B L A S T U N IT F O R OAST C L E A N IN ' Courtesy LeTouw r' at least 75%, Figure 2 shoves ,the condition of the tube that jailed: Other tubes were found eroded adjacent to U bolts holding baffle tiles. The U bolts 'provided suf ficient interruption in as flow to cause eddy currents an|d localized impingement. (Fig. 3.) Erosion by particles* of fly ash and unburned fuel has also been found in stoker-fired boilers. At the time of each shutdown for cleaning and preventitive main tenance (at least once every four months), all areas vulnerable to erosive attack should be examined. Areas most susceptible are^ . I 1. Whdre- flow of gaseis Awakes a \ turn^thrbwin^ Out particles'of 2. Behind any cracks, breaks, or j gapsi in a gas baffl.-, 3j Adjacent t.o any) projectipn: that might divert normal flow of gases. Should the boiler be provided with an induced draft fan, observe the condition of the blading. Ab normal wear may be indicative of erosive attack in the boiler. Careful attention by all engi neers to the. problem, of erosion may well prevent a serious acci dent. in the plant. The modernization prq the Brock Candy Compa ing place at a time w*1 any product, regardless 3 or cost, can be sold. Tne tlenecks today are shortag ~ materials and skilled However, progressive b know that these condi only temporary and thati few years, companies w' not guarantee quality able tp sell their prod" Brock Candy Company tinue to be a leader in it$ cause it has refused ' to ' quality of its products days when consumer den greater than the supply of' terials and because it ha$| inaugurated a program ofi and research which will constant improvements. Candy Making* (Continued from, pge 60) not be taken for granted, a chemi cal laboratory is essential. , The Brock Candy Company is now in the process of constructing a modern chemical laboratory and training a technician to perform control analyses. The laboratory, which is located in a large air con ditioned room' near the candy cooking operations, is equipped with modern stone-topped labora tory benches, the latest chemical glassware, and such special analyt ical instruments .. as balances, vacuum oven, refractometer, and pH meter. Provision has been made for such analyses as moisture, in vert sugar, viscosity, pH, melting point, and refractive index. Many of the control tests have been de veloped specifically for the Brock Candy Company, and new pro cedures will be added from time to time as the need arises. The Industrial Research Institute of the University of Chattanooga has cooperated . with the Brock Candy Company in selecting the equipment, outlining and develop ing analytical procedures, and training a technician to operate the control laboratory. A research l project on improvement of the quality of candy has been sponsor ed by the Brock Candy Company at the Industrial Research Institute of the University of Chattanooga. Since all raw materials will be analyzed and tested in the com pany laboratory, variation in prop erties will be detected before the material is used. This procedure will assure products of uniform quality, since inferior raw ma terials will be discarded and form ulations will be based on the ac tual analysis of high grade raw materials rather than on standard procedure which do not make al lowance for variation in the in gredients. Analysis and testing will assure high quality of finished products and permit any difference in quality to be detected. In this way, any unavoidable errors in manufacture can be corrected and adequate controls instituted to pre vent their reoccurrence. The facilities of the control lab oratory will also be available for the evaluation of research and de velopment work being carried out in the factory. In addition to main taining the production of uniform high quality products, the person nel and equipment of the control laboratory will be available for many other technical assignments D ust it (Continued from page tion and dust arrestors as ` in the photograph. Note1 haust is applied through^ trunnion of the tumbler. In foundry operations or other industrial type pr housekeeping is an important^ tor influencing the generati, dust. This foundry employs five horsepower vacuum de for floor maintenance. By this/ cedure loose dust, sand, and like, is removed from the floor; is not projected into the a* phere by the movement o&jj chinery, scuffing of feet, and like. This is one impressive ; in the operation of this partie foundry. Excellent houseke is combined with a good pr for materials handled. In all of the attempts at dust* trol at the LeTourneau Com" employee cooperation is obta~ Employee c o o p e r a t i o n ` through planned program ofi ployee education and emp' participation in affairs invb the health of the worker. Periodic dust samples coll1" in the LeTourneau foundry cate atmospheric concentrate various operations well b1 what is considered as masafe working limits. ADVERTISER'S INDEX The AdvertiserspIndex is published as a convenience, and not as a part of the advertising coni Every care w ill be taken to index correctly. No allowance will be made for errors or failure to ii A Airetool Mfg. Co......................................... 129 Alken-Murray Corp. ................................. 100 Allen Bradley Co.......................................... * Allla-Chaimers Mfg. Co............................. 9 Allpax Co., Inc.............................................124 Aluminum Co. of America ..................... * American Blower Corp............... 32 American Coal Burner Co......................... 133 American Engineering Co. (H o ists). . . . 35 American Engineering Co. (S to k ers).. * American Monorail Co................................ 38 American Pulverizer Co............................. 110 Anaconda Wire A Cable Co..................... 33 Anderson Co., V. D.....................................119 Arkansas Fuel Oil Co................................ * Armstrong Machine W o rk s..................... 85 Asbestos Textile A Packing Div., Raybestos-M anhattan Corp................... * Audel A Co., Theo .................................1 3 0 Automatic Transportation Co....................29 8 Babbitt Steam Specialty Co.............. ....1 3 0 Babcock A W ilcox (Boilers) ................. * Bailey Meter Co........................................... * Baldwln-Duckworth D iv is io n ................. * Bay State Abrasive Prod. Co................. * Beico industrial Equip. D ivision................* Belmont Packing & Rubber Co........... 106 B eU , W. H . A L. D.................................... 31 Bird Archer Co............................................ * Black-Sivalls & Bryson ......................... 101 Blaw -K nox Co. (Grating D iv isio n )... * Brad-Foote Gear W orks, ..................... * Brown instrum ent Co. 28 Brownell Co.................................................. * Buell Engineering Co., Inc........................91 Builders Providence, Inc............................127 Bussm an Mfg. Co............................ 82 and 83 c Carlisle County Ice Co............................. 132 Carolina Refractories Co. ...................1 3 0 Chapman Valve Mfg. Co. ........................36 Chicago Bridge A Iron Co. .................. 117 Cities Service Oil Co. ............................. * Clark Mfg. Co................ 11 Classified Ads ............................................ 132 Cleveland Chain A Mfg. Co..................... 123 Clipper BeU Lacer Co............................. * Cochrane Corporation ............................. 104 Combustion Eng. Co. Inc............. 14 and 15 Combustion Equipment Div. .............. * Continental Gin Co. ............................... 103 Crane Company .......................................... 23 D Dart Mfg. Co.. E. M................................. 102 Davis Regulator Co............... ...131 Dayton Rubber Mfg. Co............................ * De Laval Steam Turbine Co. .................. * Detroit Stoker Co............................. * Dravo Corporation (H eater D e p t .) .... 89 Oravo Corporation (Power Dept.) . . . . 2 Eagle-Plcher Co.............................................. 95 Edge Moor Iron Works, Inc................ 4 Edward Valves, Inc. ................................. * Elgin Softener Corp......... ..........................135 Engineer Co........................................ * Ernst W ater Column & Gage Co.......... 128 Everlasting V alve Co. ............................ F Fedders-Qulgan Corp. .......................... 114 Fisher Governor Co................................... * Flexible Steel Lacing Co........................128 FlexitalUc Gasket Co. ....................... * Foster W heeler Corp. ........................ 79 Frick Company .........................................123 Fulton Sylphon Co......................... . .........97 F yr*F eeder I n d u s tr ia lS to k e rs ..................133 Gardner-Denver Co..................................... * Garlock Packing Co.................................... 27 General Coal Co.......................................... * General Electric Co.................................... 87 Golden-Anderson .ValveSpecialty Co. 133 Goulds Pumps, Inc..................................... * Gould Storage Battery Corp..................... Greene, Tweed & Co................................. 112 Grinnell Co..................................Back Cover Griscom-Russell Co..................................... * Gulf Oil Corp................................................ 105 H Hall Laboratories, Inc................. 20 and 21 Hercules Float Works ............................. 120 Hoffman Combustion Eng'g. Co............. * Homestead Valve Mfg, Co......................... I l l i Industrial Electronics Co...................... ..126 Ingalls Iron Works Co................................ International Exposition Co........... .. 18 International Nickel Co., Inc.................. * Iron Fireman Mfg. Co. ............................. * Jenkins Bros..................Inside Back Cover Johns ManviUe ............................................ 71 J o h n so n S e rv ic e Co....................................... Jones Foundry A Mch. Co., W . A........... * Kewanee Boiler Corp. Kirk & Bium Mfg. Co. 24 L Layne A Bowler, Inc................................. 124 Leslie Company ........................................ * Liberty Engineering A Mfg. Co. ............ 24 Lilie Hoffmann Cooling Towers, In c... 131 Lincoln Electric Co.................................... * Link B elt Co...................................................17 Liquid Conditioning Corp......................... * Lummus Company .................................... * Lunkenheimer Co..........................................30 M M & H Valve & F ittings Co..................... * Manze) Brothers Co.................................. 128 Marion Machine Ftiry & Supply Co. ..124 Marsh Corp., Jam es P. ......................... * M ason-Neilan Regulator Co.................. * Medart Company .......................................121 M idwest Piping & Supply Co. Inc........99 Moccasin Busning Co.............. 127 Monarch Fuse Co., Ltd. .................. * Morse Chain Co.............................................. 25 Murray Iron Works Co............... 116 Murray Mfg. Co., D. J................................ 126 N N ational Alum inate Corp. ................. 1 National Boiler Protector Co.................118 National Valve A Mfg. C o ...................... 26 Niagara Blower Co..................................... * Nicholson A Co., W . H............................. 130 Northern Equipment Co............................ 34 Norton Co. ........................ * N ugent & Co., Inc., Wm. W ............ * Oakite Products, in e.................................122 Otis Elevator Co ............... ................... 16 Peabody Engineering Corp. Peerless Pump Division ............. Perm utit Co..................................... Philco Corporation ................. Frol Pittsburgh Piping & Equipment Pllbrico Jointless Firebrick Co.' Powell Co., Wm........................... Power Show, 17th National ..if Powers Regulator Co. ............. Prat Daniel Corp. ........................ Pritchard A Co., J. F ......................J Q Quaker Rubber Corp.................. R t. Raybestos-Manhattan Corp. (As . r tos Textile & Packing Division] Refinery Supply Co. ................. Reliance Electric A Engineering'^ Co. ..................... ..Inside Fro: Republic Flow Meters Co........... f Republic Rubber Division . Richardson Scale Co.................. Ross H eater & Mfg. Co...............^ Roto Division ............................;J Round A Son, David ...............; j.SJ s Sarco Co., Inc............................ . . . .. Shaw Co., Benjamin F. . . . . . . . . ',2 Shell Oil Co., Inc........................ Shepard Niles Crane A Hoist Sinclair Refining Co. ............... a] Skinner Engine Co.......................* Smith, Inc., Winfield H ................. # Smooth-On Mfg. Co. ............... . Snap-On Tools Corp. ................. Socony-Vacuum Oil Co. ......... *,^i Southern Natural Gas Co. ........ ^ Southern Rail *ay System . . . . . Southern Supply A Equip. Co. .1 Squires Co.. C. E .................. Standard Oil Co............................... ,,, Strong. Carlisle A Hammond CO.^ Sturtevant Co.. B. F. ..................,* Syntron C om p an y................... TTaylor Forge A Pipe Works . . . Terry Steam Turbine Co., The M 'A v q (j P a Todd Shipyards Corp................... Trico Fuse Mfg. Co................. Troy Engine A Machine Co. '4 u U . S. Hoffman Mchy. Co......... United States Rubber Co......... V Voss Co., J. H. H. ............... Vulcan Soot Blower Corp. ...if w W ant Ads .............................. W arren Steam Pump Co., IWfi W atchem oket Optical Co., Ino W ebster Engineering Co. . .. W estinghouse Electric Corp. W heeler Mfg. Co., C. H. . .. W ilson. Inc., Thomas C. . . . W ing Mfg. Co., L. J ........... W rigley Jr., Co., William . Yarnall-W aring Co.