US2102725A - Refrigerator car - Google Patents

Description

J. LITHG'OW REFRIGEBATOR GAR Dec. 21, 1.937.

, y1933y 5 sheets-sheet 1 Filed Jan. lll

Irufenjg.

Dec. 21, 1937. l 1 lTHGOW 2,102,725

.REFRIGERATOR GAR Filed Jari. 11, 1955 5 sheets-sheet 2 imggfx. fon 1Q/golf Dec. 21,1937. .1. LITHGOW REFRIGERA'OR CAR 5 sheets-sheet s Filed Jan. 11, 1933 Dec. 21, 1937,

J. LITHGOW REFR IG ERATOR CAR Filed Jan. ll, 1933 5 Sheets-Sheet 4 Irnfenm vorne s.

INN

Dec. 21, 1937. J. LITHGoW 2,102,725

- REFRIGERATOR CAR Filed Jan. ll, 1935 5 Sheets-Sheet 5 f. Patented Dec. 21, 1937 UNITED STATES PATENT oFEIcE American Car Corporation, corporation of Illinois Chicago, Ill., a

Application January 11, 193s, serial No. 651,156

. 7 Claims.

This invention relates to certain new and useful improvements in a mechanical refrigeration system of the compression type and more particularly to such a refrigeration system especiaily adapted for use in connection with railway refrigerator cars.

In an apparatus of this improved type, a compressor is supported beneath the car body and is driven from the running gear of the car when the 10 car is in motion. Ordinarily the compressor does not function when the car is at rest, but a driving motor is provided, which may be energized by current from an outside source, so that the compressor may be driven to cause the refrigerating system to function when the car is idle for a considerable length of time; or in order to pre-cool the car before the car is put into service. The compressed refrigerant flows from the compressor to a condenser which is housed in a partially closed compartment preferably beneath the car.

t The improved condenser is compact and provided with extended radiating surface, and means are provided for enforcing a circulation of air through the housing to effect the desired removal of heat.

The condensed liquid refrigerant gravitates into a receiving tank from which it is led upwardly into the storage compartment of the car. The improved heat-absorbing mechanism within the car comprises evaporating coils from which the 3o expanded refrigerant is drawn back to the compressor. The heat-absorbing mechanism com-.- prises one or more brine tanks, in each of which an evaporator coil is positioned. A plurality of evaporating coils are positioned outside of the brine tanks. The refrigerant supply line leading from' the. liquid refrigerant tank is provided with an expansion valve and with a thermostatically controlled distributing valve which functionsin response to changes in the temperature existing 40 within the storage compartment of the car. When the temperature within the car is above a predetermined maximum, the distributing valve functions to direct the refrigerant `entirely through the outside coils so that -the cooling energy will be devoted almost entirely to abstracting heat from the air within the storage chamber of the car. When the car temperature has been lowered below this predetermined maximum, the distributing valve functions to direct the refrigerant through the coils within the brine tanks instead of through the outside coils. The greatenportion of the cooling energy will then be used in abstracting heat from the brine and lowering its temperature, thus storing up a cooling (ci. iz-117) medium which functions to carry on the refrigerating process when the car is iule.

'I'he principal object of this invention is to provide an improved refrigerating system for refrigerator cars, of the type briey described here- 5 inabove and disclosed more in detail in the specications which follow.

Another object is to provide a simple, ecient and highly economical system of refrigeration adapted to maintain the car temperature within 10 a predetermined, but adjustable temperature range.

v.Another object is to provide a refrigerating system of this type embodying means for storing cooling energy while the car is in motion and the 15 refrigerating system is functioning, whenever this cooling energy is developed in excess of that necessary for the immediate purpose of refrigerating the car.

Another object is to provide an improved form '2o of condenser for use in refrigerating systems of the type herein disclosed.

Another object is to provide improved means for enforcing a flow of .air in contact with the condenser coils, whenever the refrigerating sys- 25 tem is functioning.

Another object is to provide an improved compressor and condenser combination 4adapted to compress the refrigerant and abstract heat therefrom in successive stages. 30

Other objects and advanages o f this invention will be more apparent from the following detail description of certain approved forms of apparatus constructed and operating according to the principles of this invention. 35

In the accompanying drawings:

Fig. 1 is `a side elevation of a portion of the improved refrigerator car, parts being broken away to.- disclose enclosed portions of the mechanism.

Fig.- 2 is a horizontal section, taken directly beneath the roof of a' car such as shown inFig.

1, the opposite end portion of the car being shown.

Fig. 3 is aplan view ofl that portion of the refrigerating. system which is suspended beneath the car body.

Fig. 4 is a. transverse vertical section, taken substantially on the line 4-4 of Fig. 1.

Fig. 5 is a horizontal section through the im: 50 proved condenser, the view being taken substantially on the line 5 5 of Fig. 1.

Fig. 6 is an elevation of one end. ofthe condenser, the view being taken looking in the direction of the arrow 6 in Fig.`5, and the enclosing 55.

screen being partially broken away to show the interior construction.

Fig. 7 is a partial side elevation, and partial longitudinal vertical section through a portion of the refrigerator car, showing a different form of the heat-absorbingor evaporating mechanism located within the car.

Fig. 8 is a partial longitudinal vertical section through one end portion of a car, showing a modified form of the condensing apparatus.

Fig. 9 is an elevation, partially in vertical seotion, showing a multi-stage compressor and the improved condenser modified to cooperate therewith.

The refrigerator car itself may be of usual approved construction, the car body comprising side walls I, end walls 2, roof 3 and floor 4, all of which are suitably insulated to minimize the transfer of heat through the walls to or from the enclosed storage chamber 5 in which the goods to be transported and refrigerated are carried. The two ends of the car body are supported from the car trucks 6 which swing about the bolster pivots 1, each truck comprising a pair of axles 8 on which are mounted the car wheels 9.

The principal elements of the refrigerating system are the compressor A, the condenser B, a receiving tank C for the liquid refrigerant, an expansion valve D, a thermostatically controlled distributing valve E, and a suitable heat-absorbing assembly indicated generally at F, all of these elements being connected in-series in the order named'.

'I'he compressor A, which may be either of the rotary or the reciprocating type and which may be single or multiple stage, is supported beneath a central portion of the car body in a suitable housing I0 which is preferably of an open-work construction so as to permit a circulation of air therethrough while at the same time providing suitable protection for the mechanism housed therein. Normally, the compressor is mechanically driven from one of the axles 8 of the car, when the car is in motion, the compressor ceasing to operate when the car is temporarily at rest. As here shown the compressor is driven through an improved form of belt gearing which is disclosed more in detail and claimed in applicants copending application, Serial No. 651,158 filed of even date herewith. Briefly described, this gearing'comprises a driving pulley I I secured centrally upon one of the axles 8, a driven pulley |2 suitably supported beneath a central portion of the car body adjacent the housing I0, and a plurality of separate belts I3, preferably of Wedge-shaped cross section which connects the two pulleys I| and I2 and transmits power therebetween. A suitable movable spring-tension supporting means is provided for the pulley I2, so as to keep the belts I3 under proper tension, this supporting means being omitted in the present disolosureffor the sake of clearness The pulleys and I2 are so designed that the pulley may swing out of proper alignment with the pulley I2, when ffthe car is traveling upon afcurved portion -of the track, Without having the belts I3 leave the pulley grooves. This improvement is disclosed and claimed in the copendingfapplication hereinabove referred to. suitable flexible shaft comprising the universal joint 4 and I5 and the intermediate extensible` shaft section I6, connects the shaft von which driven pulley` I2 is mountedlwith a drive shaft I1 supported in suitable bearings within housing I0. A sprocket wheel I6 on shaft I1 is connected through sprocket chain I9 with a sprocket wheel 20 secured on the drive shaft of the compressor A. A motor 2| supported within housing I0 may be driven from any suitable source of outside power, the power connection being made by means of the receptacle indicated at 22. A driving pinion 23 is mounted on one end of the motor shaft. A gear 24 slidably mounted on shaft I1 and operable by a clutch lever 25 is adapted to be engaged alternatively with either the motor pinion 23 or a clutch member 26 which is driven by the flexible driving shaft. When the gear 24 is thrown into engagement with clutch member 26, the motor 2| will be disconnected and the compressor A will be driven from the car axle 8 through the train of gearing hereinabove described. When gear 24 is drawn out of engagement with clutch member 26 and`intermeshed with pinion 23, the compressor A may be driven from motor 2| and the belt gearing mechanism is temporarily disconnected from the compressor. It will be apparent that other forms of driving mechanism might be provided for imparting motion to the compressor A, although the one here given by way of example is preferred.

The condenser B might be mounted in any exposed position. outside of the car body so that the heat may be dissipated therefrom, but this condenser is preferably constructed in the compactl form here shown so that it may be supported beneath the car body and adjacent the compressor. The condenser comprises one or a plurality of pipe coils provided with an extended radiating or heat-transferring surface and housed within a suitable chamber through which a circulation of air is enforced so as to eficiently and rapidly dissipate the heat from the compressed refrigerant. In the example here shown the condenser comprises four separate pipe sections or coils 21, 28, 29 and 30 which are respectively connected at their upper ends to a header 3| into which the compressed refrigerant is conducted from the compressor A through pipe 32. The lower ends of the several pipe sections connect into a second header 33 from which a pipe 34 leads into the receiving tank C which may be conveniently supported beneath the condenser. Each of the coils comprises a plurality of parallel pipe sections 35 connected at alternate ends by loops 36 and 31 so that the condensate will gravitate successively through the horizontal sections 35 and thence out through header 33 and pipe 34 into the receiving tank C. The several coils 21 to 30 are positioned with their horizontal pipe sections 35 substantially parallel with one another, and all of these substantially horizontal pipe sections are mounted in and extend through a system of spaced aparty vertical radiating or heat-transferring fins 38 which greatly increase the radiating or heat-transferring surface. This heat-transferring assembly lis mounted in a housing 39, one open end of which is covered by a screen 40 so as to protect the condenser assembly while permitting free flow of cooling air through the housing. The opposite end of housing 39 tapers outwardly to a reduced portion 4| in which is mounted a fan 42. A sprocket 43 on the fan shaft 44 is connected by chain 45 with a. sprocket 46 mounted on drive shaft I1. In this manner, whenever the compressor A is being driven (either by the motor 2| or axles) the fan42 will also be driven to enforce a. circulationvof air'through the condenser housing. 39. This formof condenservis quite compact and capable of quickly 75 and efciently dissipating the heat absorbed from storage compartment 5, and also developed in the compressor A. The air circulation through the housing 39 is positively enforced by the fan 42 so that the operation of the condenser is independent of wind conditions or the movements of the car. l

Preferably an `oil interceptor 41 is positioned in pipe 32 leading from the compressor A to the condenser B. This interceptorl'will remove oil carried in suspension by the high-pressure gaseous refrigerant forced from compressor A, and

thus avoid oil troubles in the condenser B and other portions of the circulation system.

A supply pipe 48 for the high pressure liquid refrigerant leads from receiving tank C upwardly to the upper portion of storage chamber 5 where the expansion valve D is interposed between this supply pipe andthe extension 49 thereof which leads to the distributing valve E. The expansion valve or reducing valve D may be made of any approved construction and this valve separates the high pressure side of the refrigerant circulation system from the low pressure side in the usual manner, although a further'pressure reduction may be 'accomplished in the restricted passages of the distributing valve E. 'I'he automatically operated thermostatically controlled valve E is preferably of the type disclosed and claimed in the copending application of Kopsa and Brigham, Serial No. 546,8111,l filed June 25, 1931. Briefiy described, this valve. com-g prises a distributing valve housing 50 in which is a movable valve member actuated by the thermostat consisting of a plurality of coupled bimetallicbars 5I. into distributing chamber 50 and two alternative supply pipes 52 and 53 lead therefrom. At all temperatures to which the thermostatic member is exposed above a certain predetermined critical temperature (which may be changed by an adjustment of the thermostatic mechanism) the refrigerant will be directed outwardly through supply pipe 52 and not through pipe 53. When the temperature within storage chamber 5 has been lowered below this predetermined critical temperature, the refrigerant will be directed through supply pipe 53 and will no longer flow through pipe 52.

In the form of the invention shown in Figs. 1 to 4 inclusive, the heat absorbing elements F are all positioned in the upper portion of storage chamber 5 directly beneath the roof of the car. 'I'his location has certain advantages in that the warmer air within the car rises to the top of the car so as to be directly exposed to the refrigerating element, and also this positioning of the refrigerating element leaves all of the lower portion of the storage compartment clear for the reception of lading. In the example here shown, the refrigerating elements F are divided into two similar groups which operate simultaneously in parallel with one another, the two groups being arranged symmetrically in the two halves of the car. In Fig. 1, one of these groups is shown in elevation, and in Fig. 2 the similar group in the opposite end of the car is shown in plan. A description of one group will suilice for both, and in the drawings the elements of the left-hand group are indicated by unprimed reference characters whereas the similar elements of the righthand group areindicated by similar primed ref-- under the roof where the warmer air rises. The main supply pipe 49 leads 'native supply pipe 53 is divided into two branches 55 and 55' extending to the refrigerating elements in the respective ends of the car.

In the present example each group of refrigeratin'g elements is further divided into two similar halves, one situated at each side of the car beneath the roof, the two halves being connected in parallel and operating substantially as a single unit, and it being understood that a single unit could be used if desired. The two similar brine tanks 56 are preferably supported adjacent the end portion of the car. Each of these is simply a closed tank substantially filled with brine or similar heat-absorbing medium. Inside of each of these tanks is a coil 51 through which the refrigerant circulates and yexpands to withdraw heat from the brine.

The supply pipe 55 connects through coupling 58 with the two inlet end portions 59 of the respective inner coils 51, and the two outlet endportions 60 of these inner coils connect through the coupling T 6| with the discharge or suction pipe 62. The two discharge pipes 62 and 62' leading from the two end groups of refrigerating elements connect into the main discharge pipe 63 which leads back to the compressor A. The outside coils, which normally refrigerate the car, likewise comprise two similar groups, one at each side of the car, each group comprising a coil 64 'located adjacent one of the brine tanks but outside thereof and spaced therefrom, and a similar coil 65 positioned near the center of the car, all of these coils lbeing located rather closely The supply pipe 54 connects with a T coupling 66 from which pipes 61 lead'respectively to the inlet ends of the two outside coils 65. The outlety end of each of these-coils 65 is connected by a pipe 68 with the inlet endof the adjacent outside coil 64. The outlet ends ofthe two outside coils 64v connect through coupling 6I with the discharge suction pipe 62.

In the general operation of the system as thus far described, assuming that the compressor A is being driven either from the car axle or by means of motor 2l, the compressed gaseous refrigerant will be discharged through oil interceptor 41 into the condenser B wherein the heat is removed by the air forced through the condenser casing 39, the liquid refrigerant gravitating into the receiving tank C. This liquid refrigerant is forced upwardly through supply pipes 48 and 49 through the expansion valve D and distributing valve E and, assuming that the temperature within the car is above the predeter. mined critical temperature for which the thermostat is adjusted, the refrigerant will be discharged from valve E through supply pipe 52 and thence through the twobranch pipes 54 and 54' to the refrigerating elements at the two end portions of the car. The refrigerant will flow successively through the outside coils 65 and 64 in which it expands and absorbs heat from the air within storage compartment 5, the expanded and heated refrigerant being drawn out through discharge pipes 62 and 63 and thence back to the compressor A thus completing the cycle. At this time there will be no iiow of refrigerant whatever through the coils 51 within brine tanks 56, and these tanks will not function, unless the temperature of the brine has already been lowered by a previous operation of the system in which case the brine tanks will also assist in absorbing heat from theair within the car.

When the temperature within the storage compartment 5 of the car has been lowered below the critical temperature for which the thermostats of the distributing valve E are adjusted, the valve Will be moved so as to no longer discharge the refrigerant through pipe 52, but instead discharge the refrigerant through pipe 53 which leads through branches 55 and 55 to the several brine tanks. The refrigerant now flows through inside coils 51 and thence back to the compressor through discharge pipes 62 and 63. At this time there is no ow of refrigerant through the outside coils 64 and 65. V'Ihe apparatus is so designed thatI there will be a much more rapid heat transfer between the brine in tanks 56 and the refrigerant in inside coils 51 than there is between the brine tanks and the outside air so that the temperature of the brine will be lowered considerably below the temperature of the air within the car. The heat-absorbing capacity of the group of outside coils 84 and 65 from the air within the car, is preferably substantially the same as that of the inside coils 51 from the brine Within the tanks 56, so that the load imposed upon the compressor A will be substantially constant regardless of the group of coils through which the refrigerant is flowing at any one time. The heat-absorbing capacity of the outside coils 64 and 65 will be in excess of that necessary to maintain the car temperature at the desired low point. As a result, after the desired temperature has been established within the car, the refrigerant will be directed through the inside coils 51 thus storing up cooling energy within the brine tanks 56. At such times as the car is temporarily idle (for example when the train stops at a station) the circulation system will temporarily cease to function. At such times the brine tanks 56 which have'been lowered considerably below the temperature to be maintained within the car, will continue to absorb heat from the air Within thestorage chamber thus tending to maintain the desired refrigerating temperature during these periods of rest.

It is obvious that if the car is idle for a long period of time, the temperature of the brine will be raised so that these brine tanks can no longer carry on the refrigerating action. At such times, by plugging in electric power from an outside Source at the terminal 22, the motor 2l can be operated so as to continue the action of the refrigerant circulating system, whereupon the entire apparatus will function in exactly the same manner as described hereinabove. It will be apparent that at such times the condenser fan 42 will be driven from motor 2l in the saine manner as it is ordinarily driven from the car axle, so that the desired circulation of cooling air through the condenser housing will be maintained despite the fact that the car is no longer in motion. The motor 2| may also be utilized for bringing the car down to the desired temperature after a long period of dis-use before it is again placed in service.

In the modification shown in Fig. 7, the construction and operation of all parts of the system may be substantially the same as already described, with the exception that the refrigerating elements F are of somewhat different design and are positioned in bulk-head compartments 10 at the two ends of the car instead of being supported in the main storage chamber beneath the roof.

As shown in Fig. 7, each end portion of the car is cut off by a bulk-head 1l so as to form the refrigerating chamber 10 into which heated air from the main central storage chamber 5 flows through the upper passage 12, the cooled air iiowing back into chamber 5 through the lower passage 13. A brine tank 14 is supported in upright position within chamber 1D so that there will be a free flow of air therearound, and in this tank is positioned an inside coil 15 corresponding to one of the coils 51 previously described. The branch supply pipe 55 extends to the lower end of coil 15, and the upper end of this coil connects with the discharge or suction pipe 62. Similar outside coils 16 and 11 are positioned in chamber` 1li at the two sides of the brine tank 18 but spaced therefrom so that the air can freely circulate around the coils, and a third outside coil 18 may if desired be positioned above the brine tank in the upper portion of chamber 10. The branch supply pipe 54 leads to the lower end of outside coil 16. The upper end of this coil is connected by pipe 19 with the lower end of outside coil 11, which in turn is connected in series with the third outside coil 18. This third outside coil 18 discharges through pipe into the coupling 8i connected in suction pipe 62.

This form of the refrigerating means functions in substantially the same manner as the form of the apparatus first described. This second form of the apparatus necessitates the cutting off of space in the ends of the car for the bulk-head compartments, but has the advantages over the rst described system of a better distribution of weight within the car, and the refrigerating elements are more fully protected.

In either form of the apparatus, the several outside coils may be arranged in series or in parallel, or partly in series and partly in parallel, as in the examples here given. Likewise, the several inside coils might be arranged either in series or in parallel, but preferably in parallel as here shown. It is, however, essential that the outside coils (as a group) be connected in the circulation system in parallel with the inside coils (as a group), so that the refrigerant must circulate through either the outside or the inside coils, but not both at any one time.

In the modified form of condenser shown in Fig. 8, the condenser assembly indicated generally at 82 is housed within a compartment or flue 83 formed in one end of the car body, although it will be apparent that this compartment might be positioned outside the car in any convenient location. The compartment 83 is provided vwith a lower air outlet opening 84, and an air inlet conduit 85 communicating with the upper end of the compartment extends above the car and is provided with alternative openings 86 and 81 facing toward opposite ends of the car. A swinging vane or valve 88 pivotally supported 'at its upper edge 89 is adapted to be swung by the pressure lof the incoming air against either of the stops 99 or 9|. When the car is traveling toward the left (as shown in Fig. 8) the valve 88 will be swung to the position shown in solid vlines against the stop 90, thus cutting off the opening 86 and directing air from the inlet opening 81 downwardly through conduit 85 and thence through the cooling chamber 83. When the car is traveling in the opposite direction, that is toward the right .as shown in Fig. 8, the vane will be swung to the dotted line position. It will thus be apparent that when the car is traveling in either direction a current of air will be forced downwardly through the compartment 83 and discharged through opening 84 thus dissipating the heat from the condenser coils 82. A fan 92 is positioned within compartment 83 for the purpose of maintaining this air circulation when the car is at rest. This fan may be driven by a motor 93 suitably connected in circuit with the motor 2| which drives the compressor, so that the fan 92 will be automatically operated whenever the motor 2| is used. In this manner the form of condenser shown in Fig. 8 will be effective at all times when the refrigerant-circulating system is in operation.4

It is sometimes desirable to maintain a rather high pressure difference between the high and vlow pressure sides of the refrigerating system,

95 wherein some of the heat is removed, afterl which the refrigerant passes through pipe 98 into the second stage of the compressor from which it is discharged through pipe 99 into the condenser coils 98 from which the condensed refrigerant gravitates into the tank C. In this manner the refrigerant is compressed and cooled in successive stages, and the efdciency ofthe apparatus may be considerably increased over that of a single-stage process.

I'claim: 1. In a refrigerating system, a cold-storage tank, a refrigerating coil positioned inside the tank, a refrigerating coil positioned outside the tank, the two coils being connected in parallel, and means responsive to temperature changes within the space the temperature of which is controlled by the system for circulating a refrigerant through the outside coil only when the temperature in the space is above a predeterminexl temperature, and through the inside coil only when the temperature in the space is below this predetermined temperature. l

2. A mechanical refrigerating system comprising a compressor, a condensen'and a heat absorbing element connected in a closed refrigerant conducting circuit in the order named,. the heat absorbing element comprising 'a brine tank, a coil within the' tank, a coil outside the tank, the coils being connected in the circuit in parallel, and temperature controlled means positioned in' the circuit in advance of the heat absorbing means and responsive to temperature changes in the space to be refrigerated, said controlling means directing the refrigerant through the outside,` coil only when the temperature in the space is above a predetermined temperature and through the inside coil only when the temperature in the space is lowered below this predeterr mined temperature.

3. AA mechanical refrigerating system comprisl ing a compressor, a condenser, and a heat abthe inside coil, and temperature controlled means positioned in the circuit in advance of the heat absorbing element and responsive to temperature changes in the space to be refrigerated, said controlling means directing the refrigerant through the outside coils only when the temperature in the space is above a predetermined temperature and through the inside coil only when the temperature in the space is lowered below this predetermined temperature.

4. In combination with a refrigerator car comprising a closed insulated car body enclosing a storage chamber, a mechanical refrigerating system comprising a plurality of brine tanks positioned within the car, a pipe-coil within each tank, a plurality of coils positioned outside the tanks, a compressor, a condenser and a receiving tank positioned outside the car and connected in series in the order named, means for driving the compressor from the running gear of the car, a system of supply conduits leading from the receiving tank to the several coils, an expansion valve in the supply'conduit system, a thermostatically controlled distributing valve in the supply conduit system and positioned in the storage chamber, and a return conduit system connecting the several coils with the compressor, the distributing valve functioning to direct the refrigerant through the outside coils only when the temperature in the storage chamber is above a predetermined maximum temperature, and through the inside coils only when the temperature within the storage chamber has been lowered below the predetermined maximum.

5. In combination with a refrigerator car comprising a closed insulated car body enclosing a storage chamber, a mechanical refrigerating system comprising a plurality of brine tanks positioned within the car, a pipe-coil Within each tank, a plurality of coils positioned outside the tanks, the brine-tanks and coils being Asuspended within the upper portion of the storage chamber, a compressor, a condenser and a receiving tank positioned outside the car and connected in series in the order named, means for driving the compressor from the running gear of the car, a system of supply conduits leading from the receiving tank to the several coils, an expansion valve in the supply conduit system, a thermostatically controlled distributing valve in the supply conduit system and positioned in the storage chamber, and a return conduit system connecting the several coils with the compressor, the

ture within the storage chamber has been lowered below this predetermined maximum. 6. In combination with a refrigerator car comprising a closed insulated car body' enclosing a central storage chamber and a pair of similar refrigerating bulk-head compartments one at each end of the car, there being air-circulating passages connecting the bulk-head compartments with the storage chamber, a mechanicai refrigerating system comprising a brine tank positioned Within each bulk-head compartment, a pipe-coil within the tank, a plurality of coilsv outside the tank, a compressor, means for driving the compressor from the running gear ofthe car, a condenser, a conduit for refrigerant leadf ing from the compressor to the condenser, a receiving tank for liquid refrigerant, a conduit leading from the condenser to the receiving tank, a thermostatically controlled distributing valve positioned in the storage chamber, a conduitl leading from the receiving tank to this valve, an

expansion valve in this conduit, a supply conduitl leading from the distributing valve and having branches leading to the outside coils at the two ends of the car, a second supply conduit leading from the distributing valve and having branches leading to the inside coils at the two ends of the car, the distributing valve functioning automatically in accordance with temperature conditions within the car to direct the refrigerant into either one or the other of the supply conduits, and a return conduit leading from the outlet ends of both groups of outside coils and from the outlet ends of both`inside coils back to the compressor.

'7.111 a mechanical car-refrigerating system comprising a compressor supported beneath the car body and. mechanism for driving the compressor from the running gear of the car, and a motor for driving the compressor when the car is' at rest, a condenser comprising a group of coils provided with extended radiating surface, a compartment in which the coils are housed, an air outlet in the lower portion of the compartment, an air inlet conduit leading into the compartment with oppositely directed valved openings above the car body so that a oW of air will be enforced downwardly through the compartment when the car is in motion, a fan within the compartment for enforcing a. flow of air therethrough, and a motor for driving the fan, said motor being in circuit with the compressor driving motor so as to be operative when the car is at rest and the refrigerating system is in operation.

JOHN LITHGOW.

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