Document dQdZDvX1LD0EEBdXRk6EG0EXq

Yr /// Scovill Tops Its Top \J /Veto 650-lb 750-F unit exhausts to 250-lb condens ing turbines and bleeding-condensing "top" at end of 4000-ft high-pressure outdoor pipeline I.mtial operation on June 1 of a high-pressure, high-lemperature boiler and topping turbine forms a modern climax to nearly a century and a half of industrial-power history at the Waterbury, Conn., plant of .Scovill Mfe Co. From its beginnings in 1802, this oldest of American brass factories has generated its own power; at first liter ally by "horse" power, then by water power, and, for almost a century, by steam. The story of this development, paralleling the growth of industrial power itself, will be found on page 92; here we are concerned with the record of continuous modernization necessary to keep pace with the changing de mands of tlie last 25 years. The sketch map. Fig. 1, shows the general outline of the mile-long Scovill works and the location of the east and west power houses. When the heavy loads of World War I came along, the West Power House contained two 500-kw vertical turbines, a 750-kw hori zontal unit, and two 250-kw engine generators. Twelve chain-grate-fired boilers supplied steam at 125 lb to these prime movers and to six com pound-engine-driven air compressors ex- WEST WORKS Originoffy 12 boilers (12S-St); 1st Tapping unit ' reduced to 6 in 1929.`(19291Z.--rrCcz VVv Spillway ' Carta/ (for old water wheels ) "Hamilton Avenue Fig. 1--Sketch map locates east and west power houses and pipeline hausting to the West Works heating system. The turbines were equipped with barometric condensers. East Power House construction be gan in 1915 and two 3500-kw condens ing turbines went into service late in 1916. A third similar unit was installed and the turbine room extended in 1919. The boiler house contained eight 6000- sq-ft boilers originally equipped with chain grates designed and built at Scovill's because of war-time difficulty in securing equipment. These were later replaced with Harrington travel ing grates. It is interesting to note that this plant was designed for 250 lb at a time when only a few central-stations had dared to use such ` high'' pressure. It was in 1929 that Scovill got its first `top": a rather unusual one, hut never theless true to the topping principle. It had its origin in the desire to cut costs by centralizing steam generation in the more efficient East Power House. The answer was a 4000-ft pipeline con necting the two plants. One of the 500-kw vertical units and the 750-kw turbine were removed and replaced by a 3000-kw condensing turbine designed for 2-point extraction. The high-pres sure extraction (125 lb) supplied the steam-driven compressors and the tur bine thus "topped" these units. The simplified flow diagram. Fig. 2, shows the ingenuity exercised in utiliz ing existing facilities. In winter, com pressor exhaust supplies three closed heaters in the forced-circulation hotwater healing system for the West Works. The lower extraction point on ) j the 3000-kw turbine and the exhaust from the remaining 500-kw vertical I unit, kept for standby, supplement the compressor exhaust for hot-water heat ing. Steam from the 125-lb extraction point also supplies various auxiliaries, and industrial uses in the West Works. Fig. 2--Simplified flow diagram shows how new and old "topping" units fit into and modernize existing power and steam setup, making maximum use of each Btu Existing Condensers Used The existing barometric condensers were all put to use, serving the new turbine, the 500-kw unit, the compressor engines and the auxiliaries, in summer. Under normal conditions, only enough steam goes to the condenser of the 3000-kw machine to keep the last stages cool, but the condenser makes available for emergencies the full turbine capac ity. Not only did utilization of the old barometric condensers cost nothing be yond the small sums involved in re-con nection, but their operation costs noth ing, because gravity does the work. The canal shown on the map, running along one side of the power house, stands high enough above Mad River to main tain water flow without pumping. The pipeline that takes the place of h h 78 |506) P O \V R November. I 941 RS-000143 1/17/02 an ip/'i'i' ; freezing point of water, namely 32 F. Few realize that the limit may be the acid instead of the soda-solution. Con centrated sulphuric acid of 1.835 spe cific gravity has a freezing point of about 30 F. This acid, however, will readily absorb moisture. If the stopple fits too loosely on the bottle, moisture absorption may be quite rapid, lower ing the specific gravity of the acid. When reduced to about 1.77 specific gravity the freezing point will have risen to approximately 46 F, Fig. 1. Soda-acid extinguishers should be kept at a temperature above 50 F. In exposed locations, the soda-acid extin guisher may be stored in an insulated and heated cabinet, shown in Fig. 2. Turn Current Off The soda-acid extinguisher also comes in a 40-gal size mounted on large carriage wheels. Due to the high con ductivity of the stream from either the 2y%- or 40-gal size, it is desirable to label each with a red enameled tag reading "not to be used on electrical equipment until current is off". The 2V2 gal soda-acid unit has a range of about 30 to 40 ft, and dis charge takes place for about 60 sec onds. The 40-gal extinguisher can throw a stream some 50 or 60 ft. Where it is necessary to install ex tinguishers in unheated buildings and where it is not desired to use heated cabinets, an anti-freeze type is avail able. Some are so designed that, in ad dition to turning them over, it is neces sary to bump them on the floor while in the inverted position to start the chemical reaction. Although seldom found in modern power plants, water buckets and tanks should be mentioned. A rack containing TABLE ll--SAFE DISTANCES FROM HIGH-TENSION CONDUCTORS VoUage 1100............... 2200 3300........... 5500............. 6600............. 11000............... 22000 33000............... Fresh Water 1%-in. 1 Nozzle Nozzle 6 ft 9 ft 11 16 15 22 18 27 19 29 20 30 25 33 30 40 Stream from foam extinguisher has 2J4 limes the conductivity of fresh water. Well water has 15 times the conductivity of fresh water. Stream from soda-acid extinguisher has 27 times the conductivity of fresh water. Stream from antifreeze extinguisher has 36 times the conductivity of fresh water. Sea water has 200 times the conductivity of fresh water. POWER November, 1941 fig- 1--Freezing temperature of sul phuric acid in soda-acid extinguishers five 12-qt fibre pails with tight-fitting lids is equivalent protection to one I'/ogal soda-acid extinguisher, and each pail would thus be rated A-5: five pieces of equipment (water pails) per unit of floor area as protection for Class A fires. Sometimes a 50-gal cov ered tank, full of water, with five gal vanized pails submerged in it is pro vided. Water in a full pail can lie thrown about ten feet. Where low tem peratures are encountered, the freezing point of the water may be depressed by - % adding three pounds of calcium chloride' to each gallon of water. This will be satisfactory for temperatures down to about 10 F. i- In parts of power plants such as store-. ? rooms, automatic sprinklers may be in stalled. These consist of a branched * network of pipe of varying sizes, and outlets spaced 10 ft apart both longi tudinally and transversely in the build-'' mg. with additional outlets as required over special hazards. F.ach outlet if; equipped with a sprinkler nozzle hav ing a serrated cap arranged to spread the water being discharged. This de vice, known as a sprinkler head, is kept sealed by a piece of metal having a low melting point or by a tiny glass bulb filled with liquid which expands under heat. When the temperature reaches about 135 F, solder melts or the glass bulls breaks, releasing the water. The static pressure should he not less than 15 lb at the highest sprinkler head. This may be provided by a gravity tank on the roof, by a hydro-pneumatic pressure tank in the pent house or hv a fire pump. Subsequent articles will deal v>ith equipment for use on Class !> and Ch4- C fires in power stations. RS-000144 1/17/02 NUECES Isos} i the old boilers (6 were removed and 6 converted to oil lor standby) is 10-in. in diameter and designed for 500-lb pressure. The 3000-kw turbine is also designed for 500 lb. with a dummy highpressure wheel, so that the system can operate at the higher level if future circumstances so dictate. Design of the pipeline, which is all outdoors, aimed at reducing mainte nance and possible trouble to a mini mum. Covering consists of an inch of high-temperature insulation, 3 in. of 85% magnesia, and sheet-metal lagging. At selected points, rigid anchors divide the line into sections and. between these points, expansion loops and slip joints (where space isn't available for loops! take care of thermal expansion. Single-roller guides on' straight runs and double-roller guides at bends sup port the line between anchors. All bearings on the rollers are chromium plated apd require no lubrication. Minor cliSfiges in design, anil installa tion of Alemite fittings for packing lubrication, have reduced slip-joint maintenance to the vanishing point. The entire line pitches toward the West Power House and contains not a single drain, all condensate coming out in a large combination separator and re ceiver at the west end. By eliminating need for handling coal and ash at two places, and three shifts of boiler-room labor, installation of the pipeline paid its $150,000 cost in about 4 years. "Topping the top" represents the lat- Fig. 3--New 4-drum pulverizr<f-io.i!;iintoi!-fireii high-pressure holler m Fig. 4--Rough plan of East Power House, showing new boiler ami turbine and modifications to coal- and ash-handling sistems Fig. 5--One of two duplex turbine-driven furred- and induced-draft units eipiippcd with lane control POWER November, 1941 RS-000145 1/17/02 NUECES r 807; 79 est but certainly not the last step in the continuous modernization of Scovill power facilities. Just as was the case 25 years ago. the present emergency has thrown a tremendous load on the works and the farsighted planning that lead up to the new high-pressure in stallation is now paying dividends. All steam from the 225,000-lb-per-hr, 660-lb 750-F boiler goes through the new 5000-kw turbine which exhausts at 250 lb to the East Power House turbines and to the pipeline. Several of the older boilers operate to supplement the 250-lb steam from the turbine exhaust. The new boiler, a 4-drum, bent-tube unit, has a fully water-cooled furnace, with a dry hopper bottom, designed for a conservative heat release of 21,300 Btu per cu ft per hr. The horizontalflare pulverized-coal burners are fitted with oil burners; on oil the unit has a rated continuous capacity of 250,000 lb per hr. Two 146,000-gal steel tanks (above ground) store oil for emergen cies or for use when price is favorable. A combined preheating and pumping unit takes care of oil handling. Coal comes to the plant by rail'Jrom New Haven, where tidewater shipments are received from Norfolk. The coal handling system for the 250-lb boilers consisted of unloading pits under the tracks, with a bucket elevator to raise the fuel to a belt conveyor running through the center of the boiler house and over the bunkers (Fig. 4). To utilize the existing facilities and avoid unnecessary imestment. a belt conveyoi tank, where ferric sulphate and soda ash aid in flocculation and coagulation. After passing through gravity filters, the water goes to two zeolite units op erated on the sodium cycle. A heat exchanger, fed by condensate from the continuous-blowdown flash lank, raises makeup temperature before it goes to the deaerating heater. Sulphite addi tion at this point controls residual oxy gen and caustic raises pH. The two boiler-feed pumps, one motor- and one turbine-driven, take their suction from the deaerating heater and discharge through two closed heat ers, in parallel, to the boiler. Makeup for the 250-lb boilers comes from the new water-treating system, just ahead of till: blowdown heat exchanger. Ex haust from auxiliaries supplies the de aerating heater; steam from the 250-lb system goes to the closed heaters; and steam bled at 30 lb from the 3500-kw turbines supplies the open feedwater heaters in the old boiler house. Under normal conditions, the high- pressure boiler runs continuously at rated load (225,000 lb per hr), and all was installed at right angles to the existing conveyor, fitted with an un loader at the junction point. Still an other conveyor was installed over the new bunker, which parallels the old. Ash handling in the old plant was unsatisfactory by modern standards; stokers discharged below into cars which were wheeled to the bucket ele vator to raise the ash to bins over the tracks. Ash from furnace- and dustcollector hoppers of the new unit goes into a completely enclosed pneumatic system which transports it to an ele vated silo just outside the boiler-house extension. A dustless unloader dis charges the ash to trucks driven under the silo. Two forced- and two induced-draft fans serve the new boiler. These are duplex units; a single turbine drives one forced- and one induced-draft fan. mounted on a single shaft. The auto this steam goes to the topping turbine. A reducing valve and desuperheater will supply 250-lb 600-F steam to the low-pressure system in case the turbine is out of service. About 50% of the topping unit's exhaust goes to the 3500-kw turbines. In winter, two of these units will handle the load after the topping unit does its share, but in summer, with higher river tempera tures. two units cannot swing the job and three must run. Channeling the discharge for some distance down stream. to prevent recirculation to the nearby intake, has improved circulat ing-water temperature conditions. The remaining 50% of the new turbine's exhaust goes into the long pipeline to supply the older "topping" turbine in the West Power House and through that, air compressors, steam-driven aux iliaries, and industrial uses. ElI'dric-Furnace Supply matic combustion-control system regu The 750-kw turbine-generator shown lates turbine speed and adjusts the fan in the diagram of the East Power House vanes. The forced-draft fans discharge (Fig. 2) was moved there from the through a tubular air heater; induced- West Power House to provide emer draft fans pull gas through the air gency protection for the electric-furnace heater and through multiple-cyclone supply. Normally, these furnaces re dust collectors located on the boiler- ceive emtent from the regular bus and toom floor below the fan platform. The induced-draft fans discharge to the feeders, but in the event of failure any where along the line, the 750-kw unit nearest of the existing steel slacks. In common with many industrial will feed the furnaces directly by a separate cable. Its capacity is adequate power plants, the new Scovill unit must contend with a high percentage of makeup. During the summer, this runs close to 50%. Raw water comes from Mad River and goes first to a settling to keep the furnaces at "holding" heat and prevent the costly freezeup that would follow complete service failure. Condensing facilities would'nt pay for this standby service, so the exhaust 80 |E0: POWER November, 1941 H8J0001** 1/17/M NUECES J Koes tQ atmosphere or to the heating . .system, depending on the season, i The new boiler has met all demands with ^lull satisfaction. Tests and pre liminary operating experience indicate that the guaranteed efficiency can be exceeded by a slight margin. Loads in excess of 250,000 lb per hr have been carried, with coal, and it is believed that the unit could produce 300,000 lb per hr if needed. There is a slight tendency to slagging at loads above the continuous rating and because this unit ^aust operate without shutdown during the entire heating season, it is consid'fted safer to hold it to rated capacity. *"* More H-P Boilers Planned If demands for steam and electricity continue to grow, space will be made in lthe 250-lb boiler house for additional jjiigh-pressure units, by removing sev.^ral old boilers. Because of space limt}latiois, these units will be smaller than ((ihe present high-pressure boi.er, prob ably about 150.000 lb per hr, each. The Jirgtof these projected units will replace ^e present No. 7 and 8, and the second 5 and 6. This will permit utilizing ,the existing steel stack. ,,r ;More pressing than steam aiid power .demands at the moment is demand for .compressed air. New machines and production methods using air in large quantities and a large volume of buil-1Sing construction have caused the com!pressed-air load curve to climb at a rate eral times as fast as the steam and *er curves. When this situation be- to grow acute, the main source of impressed air was the six stear.i-en pgme-driven compressors in the West lPower House, totalling 8700 cfm capacptjt; In addition, two 750-cfm motorliveli units and three portable gaso- line-engine-driven units (two owned and one rented) fed the growing load. When opportunity presented, a new 1500-cftn motor-diiven compressor was literally snatched from the market after the original purchaser had decided not to install the unit. This acquisition helped, but not enough, and five more portable com pressors were obtained, two bought and three rented. With the situation still tight, the high-pressure valve gear on one of the engine-driven compressors failed. To tide over the repair period, the operators hit on the ingenious solu tion of connecting the high-pressure supply to the low-pressure cylinder. Calculations showed the cylinder would take it. and it did, at least long enough to permit repairs to be made. Delivery of a 5400-cfin unit, driven by a 1000-hp motor and two and a half times as big as any single unit now installed, will relieve the situation, still rather tight. Operation of this and other Scovill plants is under the general direction of A J German, chief engineer, and Leo Niekerk, asst chief engineer. William Carew and William Foley supervise the East and West Power Houses, re spectively. The new installation was designed and installed by Scovill engi neers with Messrs German and Niekerk in direct charge and under the general supervision of Hugh L Thompson, con sulting engineer of the Scovill Mfg Co. Shepard T Powell was consultant on the water-treatment system. Principal New Power-Plant Equipment U\ ^Generating Equipment: Scovill Mfg Co, and water-cooled furnace.......................................Riley Stoker Corp 4-drum unit; 225.000 lb per hr of 660-lb 730-F steam, contin- ratinc on coal; 250,000 lb per hr continuous on oil; 84% tranteed efficiency at 225,000 lb per hr; 12.500 sq ft boiler sur- [e; 6812 sq ft waterwall surface; 19 ft 6 in. furnace width; 165 cu ft furnace volume; 21,300 Btu per cu ft per hr heat re- e; 3030 sq ft superheater; and steel-clad insulated setting eater. 33,000 sq ft............ .................................................... Riley Stoker Corp Auxiliary Equipment: \ risers, coal feeders. 2 each.........................................Riley Stoker Corp m. 4, horizontal flare....................................................... Riley Stoker Corp umers (combined with p-c units).........................................Engineer Co scales. 2 ................. ........................................... Richardson Scale Co nation control...........................................................................................Hays Corp lowers .......................................................Diamond Power Specialty Corp glasses .......................................................Diamond Power Specialty Corp turn valve! ............................................................................................. Crane Co ,ter regulators (Copes).................................... Northern Equipment Co heat insulation .................................................... .................. Johns-Manville Equipment: and induced-draft fans, duplex, 2 units,...B F Stuctevant Co Lglc Westinghouse 63S-hp, 250-S-lb, turbine drives, through a png gear, one 40.000-cfm forced-draft fan and one 6S.000-cfm d-dratt fan: beth fans equipped with vane control ^lectors, muhip'.e-cyclone............................... Buell Engineering Corp Waterbury, Conn. Oil pump and heater unit................................................................ .. .Engineer Co Ash and flyash removal system....................................United Conveyor Corp Pneumatic collection system from furnace hoppers and dust-col. lector hoppers; storage silo; and dustless unloader Feedwater System: Boiler-feed pumps, 2...................................................................... Ingersoll-Rand Co 300.000-lb-per-hr 3600-rpm units, one driven by a 500-hp Westinghouse motor, the other by a 450-hp, 250-5-lb turbine Closed feedwater heaters .....................................................Griscom-Russell Co Deaerating heater ......................................................................................... Permutit Co Makeup-water treatment system............................................................... PermutitCo Settling tank with motor-driven agitator and ferric sulphate and soda-ash feed tanks and pumps; two I0xl4-ft gravity filters; two zeolite softeners with brine and salt-storage tanks; sulphite and caustic distributor; phosphate-dissolving tank and pump; two booster pumps Continuous blowdown system...................................................................... PermutitCo Flash tank; blowdown heat exchanger Power-Generating Equipment: Turbioe-genorutor..........................................................................Oen.r.l Electric Co Throttle pressure 650 lb. backpressure 250 lb *; 5000-kw, 3600-rpm 0.8-pt. 3-phase. 60-cycle, 4600-vBlt, completely enclosed, air-ccrf** generator M iscellaneous Equipment: Meters and instruments................. Bristol Co. Hays Corp, Cochrane Corp, fifgl H Ash-Handling Equipment. Tfojt Sveycrs. 2..................................................................................Link-Belt Co connect existing coal-handling equipment to new bunker ,, p.pmg and valves Foxboro Co, Sentry Co ................................................................ M W Kellogg Co Backpressure relief valves.......................... Consolidated Safety Vaive Div Pressure-reducing valve, desuperheater............ Republic Plow Meters Co RS-000147 1/17/02 K";I I Troubleshooting Fluorescent Lamp With the introduction of fluores cent lamps three years ago, man-made lighting came another step closer to competing successfully with daylight, both as to quantity and quality. Through this development, not only has artificial daylight been made available at high efficiency, but 50 and more footcandles are now being provided without the dis comfort from heat usually associated with high intensities. This new source, as explained in Power (Nov 1940, p 74), differs radi cally from filament lamps both in appearance and characteristics. New information is being accumulated daily regarding the operation of fluorescent lamps under various conditions. As found by actual experience, such factors as temperature, drafts, and various cir cuit conditions will materially affect lamp performance. Another source of possible difficulties lies in improper equipment connections. These may cause peculiar lamp behavior, some times difficult to understand. A knowl edge of these factors should enable the user to obtain the most satisfactory serv ice from the lamps, and also enable him to take corrective measures in cases where unusual operating conditions prevail and impair lamp service. Dean M Warren and L R Keiffer, General Electric Co l experts, tell of a few things that happen in the life of rescent lamp, their causes, and how to find the trouble and that the lamps should be replaced. ft is normal for the lamp to show a general darkening throughout the tube, but unless a long-life lamp is compared to a new one. the difference isn't noticeable to the casual observer. Sometimes a mercury deposit collects at the lamp end and is confused with normal end blackening. This deposit is most common in the 1-in. diameter lamps and often becomes evident soon after the lamps are lighted. Generally it evaporates after a short time of opera tion. although it may reappear after the lamps have cooled. Someth) mercury spot will appear or a cold object is allowed to lii for a short time. If this sho near the center section of may not evaporate. Rolatin 180 degrees in the socket is fill when this situation Blackening at the ends of a normal occurrence. Honeblackening occurs early in is a signal that the lamp umlei abnormal conditions occurs it can be generally Lamp Sizes While the common lamp sizes have a design life of 2500 hours, it is not un likely for some lamps to fail at the end of a few hundred hours, while still oth ers may operate for 5000 hours. With respect to life-expectancy, however, the lamps conform to the same general pat tern of the filament lamps, in that the early failures are offset by those of long life. This provides the average of 2500 hours. Normal lamp failure occurs when the active material with which the elec trodes are coated is used up. Most of this material dissipates during starting, giving rise to the observation that switching the lamp on or off repeatedly is an important factor in lamp life. On the average, however, if the lamps are on 3 or 4 hours at a time, they should live their rated life. When the lamps blink on and off at the end of life, it signifies that the active material is gone Some typical lamps now in use. Wattage? and sizes are mamifac 82 [810) RS-000148 1/17/02 NUECES POWER