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March 8, 1938. . 2,110,581 H. 1.. SMITH, JR RAILWAY CAR AIR CONDITIONING SYSTEM Filed Aug. 17, 1935 4 Sheets-Sheet 1 R. \Q ,\ A . IN BY P ' W,WW+QZM4 ATTORNEYS March 8, 1938. H. |_. SMITH, JR 2,110,581 RAILWAY CAR AIR CONDITiONING'SYSTEM Filed Aug. 17, less‘ 4 Sheets-Sheet 2 .m@ /’/ , ‘(I INVENTOR mm _ ‘ ‘ I BY , ‘ a ( I v/fv ATTORNEYS March 3, 1933- 2,110,581 ' H. L. SMITH.‘ JR RAILWAY CAR AIR CONDITIONING SYSTEM Filed Aug. 17, 1935 4 Sheets-Sheet 3 lNVéNTOR l BY ‘/ dwcvk/v. ATTORNEYS ' A‘? March 8, 1938. H. L. SMITH,VJR 2,110,581. RAILWAY CAR AIR CONDITIONING SYSTEM Filed Aug. 17, 1935 4 Sheets-Sheet 4 INVENTOR M, z'nusl Patented Mar. 8, 1938 2,110,581 RAILWAY ‘DAR A CONDITI?NHNG SYSTEM Horace H4. 8th, in, lltlcond, We“, osslgnor to Thermal Engin w 1: s’ Con-pollution, Richmond, We... a coration oi Virginie Application A it, 1935, Serial No. M1535 ‘This invention relates to air conditioning and ereted systems now in use, the control is inter~ more particularly concerns an improved air con ditioning system for use on railway passenger cars mittent, the epperatus operating at maximum of steam roads. CR ‘ , The provision of conditioned air in railway pas senger cars involves generally two conflicting problems; that of maintaining comfortable con ditions and that of economy. The power avail able on steam trains for the operation of auxiliary capacity whenever it is turned‘on. Since the system must have scient capacity to prop, erly cool the car under the most adverse outside 5 temperature, conditions met with in operation, the intermittent control produces undesirably wide fluctuations in car temperature under moderate outdoor conditions, and iurther results in lowered _ equipment, such as air conditioning apparatus, is e?iciency due to the power losses involved in ~10 quite limited. starting the apparatus at frequent intervals. With the above and other considerations in On the other hand, passenger cars are necessarily subjected to widely varying tem perature conditions'in the course of an average run and comfortable atmospheric conditions can be maintainedtherein only if a very ?exible sys ' tem of relatively large cooling capacity is pro” vided. is controlled in an emcient and economical man- - ner by varying the cooling effect in accordance with the heat load imposed whereby the our air , ‘ 'inhthe past, railway car air conditioning sys tems have been a compromise between two de sired ends, the maintenance of comfortable con ditions and reasonably economical operation. Known systems operated in whole or in part by electricity involve a high initial cost and high operating expense due to their low emciency. Thus when such systems are installed on a rail way car, it is necessary to replace the usual car lighting generator and battery with electrical generating and accumulating equipment 01’ greatly'increased capacity and this replacement materially increases the initial cost of the in stallation. The energy for operating electrically driven systems is delivered from the locomotive through the draw bars, the axle driven generator, the storage battery and the electric motors to the refrigerating apparatus, and consequently, the overall ei’?ciency of the system is low and the operating cost correspondingly high. mind, it is proposed in accordance with the pres~ ent invention to provide an improved railway our air conditioning system for steam trains which 15 ~ Steam operated railway car air conditioning systems employing steam jet vacuum boosters 40 have been used to a certain extent, and in general, are more economical to install and operate than temperature is maintained at the desiredvelue without wide fluctuations. Other objects of the 20 invention include a system of this nature which is small and compact, inexpensive to install and low in operating cost. A further feature oi’ the invention involves the provision of improved and I simpli?ed means for operating the system when 25 the railway car is standing in a yard or station with‘ no locomotive connected thereto whereby a car may be precooled before‘ it is connected in a train and occupied by passengers. In general, the above and other objects of the 30 invention are carried out by providing a com“ pression type reirigereting system to‘ cool the car and driving this system with a steam prime mover capable of e?icient operation over a wide range of speeds. In accordance with the inven- 35 tion, the speed of the prime mover and hence the speed of the refrigerant compressor is varied by means responsive to atmospheric conditions in .the car, and in this manner, the car tempera ture is maintained constant at the desired value 40 and a, very high operating emciency is obtained. I have found that a reciprocating steam engine electrically driven systems. However, such sys tems operate effectively under maximum steam ‘ of the uni?ow type is particularly adapted for supply only, since the e?lciency of a. steam jet or use in my improved system. The speed control is conveniently accomplished 45 injector in creating a vacuum falls rapidly as the steam pressure on the jet is reduced, and as a by adjustment-of the steam supply to the prime mover and to this end, I preferably provide means practical matter, effective cooling can be ob tained only if the steam is" supplied continuously responsive to both the speed of the prime mover at the rated pressure. The piping available for andthe temperature of the car, whereby the com all supplying steam to the various car carried units pressor operates at a speed which is maintained 50 of a train is-limited in size, and when a large constant in spite of steam pressure variations or number of car units are in operation, the steam variable load factors so long as the car tempera ture is within thedesired range, but which speed ful operation and insu?lcient car cooling results. is varied to compensate for departures from the 55 In both the electrically driven and steam op- , desired car temperature conditions. 55 pressure falls off in the rearward cars and waste- , 2,110,681 Therefrigerant compressor is a constant volume device, acting on a relatively dense gas, and ac cordingly, the compressor efilciency increases as tional construction which has been diagrammat ically illustrated at P in Figures 6 and 'l. The system is of the type in which a refrigerant from its speed drops. High compressor speeds result a refrigerating unit, or a suitable heat transfer in high gas velocities and high friction losses. There is, of course, a low limit to the, speed at medium cooled by such refrigerant, is circulated in heat exchanging relation with air supplied to which it is economical to operate a refrigerant or circulated in the car. The particular form of car cooling coil and air propelling means forms no compressor since the relation between the initial investment and required capacity must be taken part of the invention and various forms of appa However, since heat load condi-' ratus may be employed for this purpose. In the 10 into account. 15 one or more intake openings 3 into a chamber 4 20 tem is better suited for use with steam supply facilities of multiple-car trains than previously known systems. With known steam systems, which are governed by a full-on or full-oi! con trol, the units on the several cars of a train fre 25 quently operate simultaneously and the rapid steam consumption ‘by the forward car units so far reduces the steam pressure on the rearward car units that these units operate very ine?l ‘ciently and usually fail to produce the required 30 cooling effect’until after the forward car units have stopped operating. With. my improved variable speed steam system, the amount of steam drawn from the train line by each unit is throt tled to the minimum value which will maintain 35 the desired car temperature under continuous operation, and sudden ?uctuations of train line steam pressure with resultant ine?icient or inade quate operation of the rearward car units is avoided. - In accordance with one embodiment of my in vention, I provide an. over-running clutch or equivalent means in the driving connection be tween the steam engine and the refrigerant com pressor, and further provide an electric com 45 pressor driving motor which may be readily con 40 nected directly to drive the compressor independ ,ently of the steam engine. With this arrange side outlet, the steam engine remaining station ary during such operation because of the over running clutch in its driving connection. In describing the invention in detail, reference 55 will be made to the accompanying drawings in ‘ ' Figure 1 is a plan view of a car carried refrig erating unit embodying the invention; Figure 2 is a side elevation of the unit shown 80 in Figure 1; ‘located above the ceiling of .the car vestibule ‘I, and is propelled by the fan through a duct 5 to suitably placed ceiling outlets 6 in the car. 'A cooling coil 8 is located in the chamber 4 in heat exchanging relation with the air drawn there thrnugh and this coil is at times supplied with refrigerant or other cooling ?uid from a refrig erating unit hereinafter described. The fan 2 may be operated by an electric motor, as shown. The fan and motor may be of relatively small capacity and may replace the usual electric fans customarily installed in railway passenger cars. 25 Air may be discharged from the car through the doors, windows or other air pervious openings thereof, or special air outlet ducts may be pro— vided, if desired. The refrigerant‘ for cooling the air delivered to 30 the car is supplied by a refrigerating unit carried beneath the car in a housing generally designated H. Thehousing may take any suitable form and is preferably disposed beneath the car frame and between the center line of the car and the clear 35 ance limits at one side thereof, as shown in Fig ure 3. i The refrigerating unit proper comprises gen erally a mechanical refrigerant compressor 10, preferably of the reciprocating type, a refrigerant condenser C and suitable means such as the fans II and I2 for drawing a current of cooling air over the condenser surfaces. The intake I3 of the compressor III is connected to draw refrig erant gas from the car coil 8 by a pipe l4, prefer ably provided with ,a cut-off valve IS. The dis charge IS, of the compressor I0 is connected ment, the‘ car may be pre-cooled by merely con necting the electric motor to the refrigerant 50 compressor and supplying current from a track which; 10 embodiment shown in Figure 6, fresh air from outside of the car is drawn by a fan 2 through tions vary widely and operation is for the most part well below maximum capacity, I obtain a condsiderable increase in emciency by varying the compressor speed in accordance with load requirements since in this manner, the com pressor always operates at the highest efficiency obtainable for the load imposed and further, losses resulting from frequent starts are avoided. My improved variable speed steam driven sys ' through a pipe I‘! and a‘ valve l8 to the condenser C. ‘ The outlet of the condenser C passes through a cut-off valve is and a pipe '20 to the car cool ing coil 8, the proper condenser pressure being. maintained by a suitable expansion valve 2|. The condenser may take any suitable form and preferably includes ?nned coils or passages 22 communicating with a liquid refrigerant accumu lator 23. _ "I‘he condenser cooling fans H and I2 are dis posed in suitable circular openings in a shield 24 extending across the inner face of the condenser C, and air drawn through the condenser passes 60 laterally through the housing H and out through the louvers 25 in its outer wall. The fans H and Figure 4 is an enlarged detailed view, partly in I2 are journaled in suitable brackets 26 and 21 and are driven by a single shaft 28 through suit section, of the compressor driving mechanism; I Figure 5 is a sectional view of the governor able spiral gears 29 and 30. 65 mechanism; ' The refrigerant compressor ‘I0 is driven by a Figure 6 is a sectional elevation of a railwayv steam prime mover, which preferably comprises passenger car equipped with an air conditioning a direct connected reciprocating steam engine of system embodying the invention; and the uni?ow type, which is illustrated at E. In Figure '7 is a diagrammatic view of a trainof general‘, the steam prime mover employed should 70 70 passenger cars equipped with systems embodying be capable of e?lcient operation over a wide range the invention. * ' of speeds, and I have found the uni?ow type of Referring to the drawings, my improved rail steam engine admirably suited to this purpose. way car air conditioning system has been shownv The crank shaft 3! of the engine E is connected to the compressor shaft 32 through an over 75 75 as applied to a railway passenger car of conven Figure 3 is an end elevation of the car carried unit; - 9,110,581 running clutch or equivalent means 88. As shown in Figure 4, this clutch may take the form of an inner element 34 connected to the engine shaft 8| and having a ‘plurality of cam recesses 88 there in carrying balls or rollers’ 88 and surrounded by an outer element 81 ?xed to the compressor shaft 82. As will be understood, rotation of the inner element 84 by the engine E in a counterclockwise direction, as viewed in Figure 4, causes the rollers 3 the frame of the engine ‘E and driven from the engine shaft through suitable gearing, not shown. The governor has two centrifugally operated weighted elements 84, pivotaliy supported on a cross piece 85 ?xed to the governor shaft 88. A sliding collar 81 carried by the shaft 88 is moved along this shaft by the outward movement of the centrifugal elements 84, and the movement of the collar 81 is transmitted to a shaft 88 by the 38 to lock in the cam recesses 88 and so form a ' arm 88. The shaft 88 carries an arm 18 outside 10 driving connection between the engine and the of the governor casing, and a tensioned spring compressor. If the outer element 81 is driven independently of the engine E, the rollers 88 are ‘ll connected to this arm exerts a force thereon which opposes the outward movement of the cen released and the engine remains stationary. I prefer to provide an electric motor for oper ating the compressor ll independently of the engine E when the car carrying the system is not coupled to a- locomotive whereby the car maybe precooled before it is occupied by passengers. To 20 this end, a motor 88 is provided, having a friction wheel 88 on its shaft disposed parallel to the outer trifugal elements 84. The end of the spring 1| is connected to a pivoted lever 12, the movement of which varies the force exerted by the spring ‘H on the lever ‘III, as is apparent from the show ing in Figure 2. A second arm 13 is connected to the shaft 58 of the governor G and is in turn 15 member 81. of the over-running clutch. A fric tion idler 48 is slidably carried by a suitable bracket 4| and is movable to and from a position to simultaneously engage and form a driving con nection between the motor friction wheel 39 and the outer clutch member 81. The idler 48. may be operated in any suitable manner, and as shown, a pneumatic diaphragm mechanism 42 is pro 30 vided for this purpose. This mechanism includes a diaphragm 43 ‘acting against a spring 44 and operating a plunger 45 connected to the sliding journal 48 of the idler 48. Compressed air from a suitable source is supplied to the mechanism 42 through a pipe 41 under the control of a man ual three-way valve 48. when the valve 48 is manipulated to admit air pressure to the dia phragm 48, vthe idler is moved to engage the wheel 88 and clutch member 81, thus establishing a 40 driving connection between the motor 88 and the compressor Hi. When the valve 48 is manipulated to cut of! the air supply and discharge air from the diaphragm chamber of the mechanism 42, the spring 44' moves the idler 48 out of engagement with the friction wheel 88 and clutch member 31, thus breaking the driving connection. The fan operating shaft 28 is ‘driven with the connected through the links ‘l4, ‘l5, ‘I8 and ‘I1 to the stem of the steam engine throttlevalve t8. Suitable means are provided for moving the lever 12 and so varying the tension of the gov e‘rnor spring ‘H in accordance with changes in air temperature within the car P. In the dis 25 closed embodiment, this is accomplished by means of a pneumatic diaphragm mechanism 18 having a ?exible diaphragm 19 connected to the lever ‘I2 through a plunger 80. The downward movement of the diaphragm 78 and plunger 88 30 is opposed by a spring 8| and compressed air from a source indicated by the pipe 83 is sup plied to the upper surface of the diaphragm 18 through a pipe 84 under the control of a ther mostat 82 in the car. The thermostat 82' is of known construction and acts to reduce the air pressure on the diaphragm ‘I8 as the car air tem perature rises above a predetermined value, and to increase this air pressure as the car air tem perature falls below the predetermined value. 40 In- the position shown in Figure 2, it is as sumed that the car air temperature is above the prising the aligned'pulleys 58 and 58 and the belts 88 engaging these pulleys. The desired belt ten desired value, and accordingly, a low air pres-‘ sure is applied to the diaphragm ‘I8 and the spring 8| has lifted the plunger 80 and moved 45 the lever 12 to its highest position against a stop 85, placing the governor spring ‘II under maximum. tension. In this condition, the cen trifugal elements 84 of the governor are moved inward, turning the shaft“ in a clockwise di 50 sion is maintained by an idler 5| engaging the rection as viewed in Figure 2 to a point where lower span of the belts 58 and pressed against the belts by a spring 82 which is tensioned between a ?xed support and the pivoted idler carrying arm the throttle valve 56 is opened to a considerable compressor l8 through a driving connection com 83. ~ . extent, and’ the, engine E and compressor I8 operate at a comparatively high speed which is limited and controlled by the governor G. The Steam for operating the engine E is supplied - high speed operation of the refrigerating system from the locomotive 58 through the usual train reduces the car air temperature and when this steam line 5| and a branch pipe 52 leading to temperature falls to a predetermined value near each car carried unit. The steam passes through a manual supply valve 53, a water separator 54, an automatic cut-off. valve 55 and a throttle valve 55 to the engine E. Exhaust steam from the t‘" gine E passes out of the housing H through the ‘ pipe 51. the minimum comfortable temperature, the in crease in air pressure on the diaphragm 18 moves 60 the plunger 88 and lever 12 to their lowest posi tions, reducing the tension on the spring ‘II to the minimum value. The centrifugal elements 64 of the governor accordingly move outward, turning the governor shaft 88 in a counter During operation of the system, the supply of steam to the engine E is automatically governed by means Jointly responsive to the engine speed valve 55 to a point where the engine and com and the temperature of the air in the car. In pressor operate at minimum speed. If, under the disclosed embodiment, this is accomplished these conditions, the heat load in the car is so light that even at minimum speed operation the 70 refrigeratingsystems lowers the car temperature 70 by providing a speed responsive governor G con nected to operate the steam engine throttle valve 58, and by modifying the action of the governor in accordance with changes in car temperature. Any suitable form' of speed governor may be 75 used. The governor G disclosed is mounted on clockwise direction and so closing the throttle to the minimum desired value, then the resultant further increase in control air pressure acts through the pneumatic steam valve 55 to cut off the steam supply to the engine E and so stop 76 2,110,5s1 the refrigerating system. The operating mech anism of the valve 55 is of the pneumatic dia phragm type described above, and air pressure is supplied thereto from the thermostat pipe I‘ through the pipe 88, as shown in Figure 2. As the car air temperature increases from the minimum value, the reduction in the air pres sure controlled by the thermostat 82 ?rst opens ll) the automatic pneumatic steam valve 55 and so starts the engine E and compressor I. at mini ing a mechanical refrigerant compressor, means connected to said refrigerating unit for cooling the interior of a railway car, a variable speed steam engine connected to drive said compressor, means responsive to both the temperature in said car and the speed of said engine for variably controlling the supply of steam to said engine and means responsive to a minimum car tem perature for cutting of! the supply of steam to said engine independently of the action of said 10 mum speed. A further rise in car temperature means responsive to both car temperature and . further reduces the control air pressure and the engine speed. 2. A railway car air conditioning system com diaphragm ‘I! of the mechanism ‘I8 is lifted by prising a car carried refrigerating unit includ the spring ll, thus lifting the lever. ‘I2 and in 15 creasing the tension on the governor spring ‘II.’ ing a mechanical refrigerant compressor, means This increased governor spring tension moves connected to said refrigerating unit for cooling the centrifugal elements 84 inward. turning the the interior of a railway car, a variable speed shaft 88 in a clockwise direction and opening the steam engine connected to drive said compressor, throttle valve 56 to admit more steam and so a speed responsive device driven by said steam engine comprising means moved by centrifugal increase the speed of the engine E and com pressor l0. force acting against a spring, means for variably Although in the foregoing description, the controlling, the rate of supply of steam to said operation of the control equipment from maxi engine in accordance with‘the movement of said mum to minimum speed has been described, it centrifugally operated means, means responsive will be understood that under normal conditions, to the temperature in said car for varying the that is, a continuing heat load on the car, the force of said spring and further means respon system will operate continuously at some inter sive to the temperature in said car for cutting mediate speed, the governor G maintaining the off the supply of steam to said engine when the speed constant at a value determined by the car temperature reaches a minimum value. 3. A railway car air conditioning system com temperature in the car, and the thermostat al tering this speed, as required to compensate for prising a car carried refrigerating unit includ changes in car temperature. ing a mechanical refrigerant compressor, means From the above description, it will be seen connected to said refrigerating unit for cooling that the governor G and its thermostatic con the interior of a railway car, a variable speed steam engine connected to drive said compressor, 35 trol act tovary the operating speed of the re frigerating system in accordance with changes a speed responsive device driven by said steam in the heat load conditions in the car. As long as the car temperature remains constant at the desired value, the governor maintains the com 20 25 30 35 engine comprising means moved by centrifugal force acting against a spring, means for vari ably controlling the rate of supply of steam to 40 pressor speed constant but any change in car - said engine in accordance with the movement of , temperature produces a corresponding change said centrifugally operated means, and means re-_ in compressor speed which counteracts and cor rects the car temperature change. With this arrangement, the compressor operates continu 45 ously so long as cooling is required, and further operates at all times at the lowest possible speed which will maintain comfortable car conditions under the heat load imposed. Since the com pressor e?lciency rises as its speed is reduced, the ‘so system operates very efliciently and further, since sponsive to the temperature insaid car for vary. ing the force of said spring. ' ' 4. In a railway car air-conditioning system, in combination with a steam locomotive and a pin-1 rality of cars connected thereto, a train steam line arranged to be supplied with steam from said locomotive and having a connection extend ing to each of said cars, a refrigerating unit car ried by each car and including a mechanical re the refrigerating system operates continuously frigerant compressor, each refrigerating unit be 50 while cooling is required, the losses involved in ing arranged to cool the interior of the car asso starting the compressor are avoided. By the use ciated therewith, a variable-speed steam engine of the system disclosed, dependable cooling can 55 be obtained in all‘ of the cars of long trains. Due to the throttled operation of car cooling units, sudden drops in train line steam pressure on each of said cars for driving the refrigerant compressor thereon, means for supplying steam from said connections to the steam engines on are avoided- andthe operation of forward car units does not reduce the steam pressure avail 80 able on rearward cars to a point where inade to both temperature in such car and the speed of the steam engine thereon for variably con quate cooling results. Differences in train steam line pressure are automatically compensated for by the speed governors of the various car units, and accordingly it is unnecessary to manually 65 change the adjustment of car equipment in ac cordance with the position of the car in a train. I claim: _ 1. A railway car air conditioning system com prising a car carried refrigerating unit includ said cars, means on each of said cars responsive trolling the supply of steam from the associated 60 connection to said engine, whereby a sumcient amount of steam is supplied to each engine, independently of the operation of other engines, to operate its associated compressor in accord ance with the coolingrequirements of the asso ciated car, and means on each of said cars rc sponsive to a minimum car temperature for cut ting off the supply of steam to the engine. HORACE L. SMITH, JR.