US2227244A - Refrigerating apparatus - Google Patents

Description

1940- R. R. CANDOR 2,227,244

REFRIGERATING APPARATUS Original Filed March 31 1934 2 Sheets-Sheet 1 h v 5 E m n v \1 u N -4 g 3 v 81 v U N "e a Q a: M L? s; i v

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1940- R. R. CANDOR 2,227,244

REFRIGERATING APPARATUS Original Filed Mrch 51, 1934 2 Sheets-Sheet 2 Patented Dec. 31, 1940 UNITED STATES REFRIGERATING APPARATUS Robert R. Camlor, Dayton, Ohio, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware Application March 31, 1934, Serial No. 718,333 Renewed July 29, 1938 ii Claims.

This invention relates to refrigeration and more particularly to the conditioning of air for enclosures or vehicles.

An object of this invention is to provide an air conditioning system or method in which the normal refrigerating capacity of refrigerating system is utilized for conditioning the air directly or substantially at the same time that it is generated, and in which the excess refrigerating capacity to cool the holdover in an approved manner.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings Fig. 1 is a diagrammatic representation of an apparatus embodying features of my invention;

Fig. 2 is a diagrammatic representation of a slightly modified form of a portion of the apparatus shown in Fig. 1.

Fig. 3 is a vertical cross-sectional view of a modified form of holdover tank; and

5 Fig. 4 is a vertical cross-sectional view transverse to Fig. 3.

An air conditioning system embodying features of my invention includes, in general, a compartment or vehicle ID the air for which is to be 30 conditioned. A refrigerating system is associated with the compartment or vehicle I in such a manner that the system applies its refrigerating capacity to the air to be conditioned directly or at least substantially at the same time that re- 35 frigeration is produced so long as the system has sufficient capacity or excesscapacitmend applies its excess refrigerating capacity forthe cooling of the holdover which'is thereafter utilized to condition the air when the refrigerating systern-lacks sufllcient capacity to cool the air. The refrigerating system includes a. refrigerant liquefying unit H, and a first evaporator l2 in refrigerant, circulating relationship. It also in-v cludes a second evaporator I3 also in refrigerant circulating relationship with the refrigerant liquefying unit. The arrangement is such that evaporator I2 conditions air so long as the refrigerating capacity is equal to or in excess of the air conditioning requirements. The arrangement is 50 such that the evaporator l3 cools a holdover l4 in an insulated sump l5 whenever the refrigerating capacity is in excess of "the air conditioning requirements. Means are provided for conditioning the air by cooling it with the holdover I! when the refrigerating system lacks sufficient v capacity either because it is operated at an insufficient speed or because its driving means are stopped altogether, as will be hereinafter more fully explained.

The refrigerant liquefying unit may include, 5 in general, a compressor it, condenser ill and a liquid refrigerant receiver 08. The' receiver is is connected with the evaporator 112 by means of a liquid refrigerant line it and the evaporated refrigerant returns to the compressor from the evaporator l2 through the evaporated refrigerant line 20. The evaporator 53 is connected with the receiver in through the liquid line 211, and the evaporated refrigerant for evaporator 03 returns to the compressor through the evaporator 15 refrigerant;v line 22. An automatic expansion device is interposed between the receiver l8 and the evaporator M. This may take the form of an automatic constant pressure valve 23 which feeds liquid refrigerant into the evaporator I2 20 whenever the pressure within the evaporator falls below a predetermined pressure. However, this valve is also provided with a thermostaticbulb 24 placed at the outlet of the evaporator i2 which automatically closes or throttles a valve 23 when- 25 ever liquid refrigerant in excess quantities reaches the zone where the bulb 24 is placed. This arrangement tends to maintain the evaporator 02 with sufficient liquid refrigerant to wet the internal surfaces from' valve 23 to bulb 24. The evaporator I3 is also provided with an automatic expansion device in the form of a constant pressure valve 25 which tends to feed liquid refrigerant into the evaporator l3 whenever the pressure therein drops below a predetermined limit. The pressure at which the valve 25 feeds refrigerant is selected at a lower pressure than the setting for the valve 23. Thus the evaporator I2 receives liquid refrigerant in preferance to the evaporator l3 so long as the refrigerating capacity of the unit H. is only equal to or below the air conditioning requirements; but when unit I I generates excess refrigerating capacity it tends to reduce the pressure in the suction line below the limit of the valve 23 which causes the valve 25 to supply liquid refrigerant to the evaporator l3 and to refrigerate holdover l4. I

The refrigerant liquefying unit II, when it is mounted on a vehicle, may be driven by any suitable means in functional relationship to the motion of the vehicle. Thus the compressor IS-may be directly driven from the axle 26 through the medium of a belt drive 2'! or similar connection.- The refrigerating capacity of unit I l istherefore likely to change from time to time in response to varying conditions of speed, temperatures, etc. At times, therefore, the unit II may have excess refrigerating capacity beyond the requirements of evaporator I2 and the other times it may have insuflicient capacity and it is therefore desirable to prevent the unit I I from reducing the temperature of the evaporator I2 below the desired temperature. which is generally slightly above 32 F. Also it is desirable to prevent the cooling of compartment I below a comfortable temperature. To this end, means are provided for throttling the flow of refrigerant from the evaporator I2 to the compressor I6. This may take the form of a valve 28 made responsive to air conditions through'the medium of a thermostatic bulb 29 which throttles the suction line whenever the temperature of the air in compartment I0 reaches a predetermined low limit and opens the valve whenever the temperature rises above this limit or any higher limits selected. In addition, other throttling means are provided which prevent the compressor I from reducing the refrigerant temperature of evaporator I2 below 32 F., the freezing point of water. This may take the form of a constant pressure valve 30 which throttles the suction line 20 whenever the pressure in the evaporator I2 tends to fall below a predetermined limit, which limit is preferably selected to correspond to some temperature slightly above 32 F., but below the temperature desired for the air in compartment I0. It is to be understood that in the physical embodiment of the valves 28 and 30 their functions may be embodied in a single structure. The valve 28 may be of the type wherein an opening is gradually opened and closed by the bulb 29., or it may be of the type when the opening is suddenly opened and closed. In the latter case it may be convenient to provide a bleeding .by pass, diagrammatically indicated at 28a, to permit a slight amount of refrigerant to pass at all times. In such a case, the valve 28 may be a solenoid valve energized and deenergized by thermostatic bulb 29. Bulb 29 may be made responsive to dry bulb or wet bulb temperatures or both, as desired.

Means are provided for causing the evaporator I3 to cool the holdover I4 whenever the refrigerating capacity of unit I l is in excess of the requirements of the evaporator I2. This may take the form of valved connections including a check valve 3| in the suction line 22 which permits evaporated refrigerant to flow to the compressor I5 whenever the compressor tends to lower the refrigerant pressure in its intake line 32 below the pressure maintained in the evaporator I2. Thus whenever any throttling action is imposed on the line 20 by either of the valves '28 or 30, the compressor I6 tends to evaporate refrigerant in the evaporator I3. If desired, a valve 33 is provided at the outlet of evaporator I3 which tends to throttle the line 22 wherever liquid refrigerant in sufficient ouantities reaches thermal contact with the bulb 34 which tends to close the valve 33. This prevents the compressor l6 from drawing liquid refrigerant from the evaporator I 3 and prevents waste of refrigeration by evaporation in the suction line 22.

Preferably the holdover sump or storage zone I5 is placed underneath the floor of the car I II and therefore it is convenient to provide means for circulating the holdover from the sump l5 to an air condition zone, which may be conveniently adjacent to air conditioning zone occupied by the evaporator I2. Thus a pump 40 is provided with a suction line H in the sump I5, which pumps holdover through the line 42 to the i l con ition:

ing zone in coil 43 in the path of air blown by the electrically driven blower or fan 44. The holdover returns through the line 45 to the sump I5. In the physical embodiment, the pump 40 is placed sufficiently low to be self priming at. all times.

Means are provided for operating the pump 40.

whenever the refrigerating capacity of unit II falls below a predetermined limit. This may be accomplished by drivingly connecting the pump 40 with an electric motor 46 which is automatical ly energized whenever the speed of the car falls below a predetermined limit and preferably also only when the temperature of the compartment l0 rises above a predetermined comfort limit. Thus an electric energizing circuit is provided for the motor 46 which includes a battery 41, a centrifugal switch 48 drivingly connected with the wheel 49 and responsive to car speed, and a thermostat 50 which is responsive to temperatures of air in compartment Ill. The calibrations are such that the centrifugal switch 48 closes whenever the speed of the car falls below a predetermined limit and the thermostatic switch 50 closes whenever the temperature of the car rises. above a predetermined comfort limit. The battery 41 may conveniently be a storage battery which is charged by the generator 5I, having a suitable centrifugal cut out which is drivingly connected with the wheel 49. The motor driven fan 44 may also be driven by electrical energy derived from the battery 41 and which may be controlled by a switch 52 which may be either manually controlled or thermostatically controlled in response to temperatures in compartment II).

The holdover may be of any type desired. Preferably it is a liquid adapted to be frozen by the evaporator I3. Thus water may be used, and the evaporator I3 is spaced a suflicient distance from the suction pipe H to prevent the formation of ice around it. After a cake of' ice of a certain thickness is formed on the evaporator I3. the heat infiltration into the sump I5 is equal to the heat transfer to the evaporator I3 through the cake of ice. When these conditions are reached, no further ice is formed. The pipe M is placed beyond this limit, and hence the pump intake is always free. The liquid returning to the sump I5 through the pipe 45 is distributed over and flows around the ice and is properly cooled before being repumped through the cooling pipe 43.

Means are provided for preventing overloading of the refrigerating system when condenser pressures rise above a safe limit. Thus a valve 53 is provided in the suction line 32 which throttles the compressor intake whenever condenser pressures rise above safe limits. The valve 53 may have its actuating bellows connected by the pipe 54 with the discharge 55 of the compressor and may be calibrated to throttle or close the suction line 32 at any predetermined discharge pressure limit desired.

In the modification shown in Fig. 2, the compressor I 6a is driven from the wheel 6| of the car by an automatic ratio chaging transmission 62, which is interposed between the compressor and the wheel. The automatic transmission 62 may include an automatic governor which automatically changes the drive ratio between the wheel and the compressor as the speed of the car varies. The speed of the compressor I6a need not be maintained absolutely constant, although if desired the transmission may be selected to do so. Preferably, however, the transmission 82 includes a centrifugal go rnor which automatically declutches the drive and changes gear ratio under varying compressor speeds in a manner similar to transmissions, now interposed between the internal combustion engine and the wheel of automobiles. Numerous transmissions of this type are well known and their specific description is deemed unnecessary. The remainder of the system may be as shown in Fig. 1.

If desired means may be provided for stopping the operation of the compressor after the compartment I has been properly cooled and after the proper amount of ice has been formed in the holdover sump. Thus a thermostatic bulb 63 may be placed in sump Ia (which corresponds to sump I5 in Fig. 1) which closes switch 65 and energizes a solenoid 66. Thus solenoid 66 declutches the clutch in transmission 62 or a supplementary clutch, if desired, and stops the compressor. Thereafter the compressor is not actuated until ice has melted away from bulb 63 in sump I511 either because of heat infiltration into the sump or because of circulation of water tothe air conditioning zone in response to air conditioning demands through control of a thermostat 50.

In certain embodiments, it is desirable to provide means permitting the use of auxiliary refrigeration where the car stands idle after the holdover refrigerating power has been consumed. This may be accomplished by the use of a modified form of sump in the system shown in Fig. 1. The sump I 5 of Fig. 1, under such circum-, stances may take the form shown in Figs. 3 and 4. The su'mp may be suspended under the car with the side I00 adjacent the side ofthe car. The sump is provided with a water, or other holdover, section IN, and with an auxiliary ice section I02. The section IN is provided with an evaporator I03 corresponding to evaporator I3 of Fig. 1. A pipe I00 leads to a pump similar to 40 and the holdover returns to the sump through pipe I05 from an air cooling section similar to 03 of Fig. 1. The pipe I05 is provided with a plurality of spray heads I06. The auxiliary ice section I02 is provided with ice supporting racks I01 and vertical baflles I08. 'Oneor more cakes ofice I 09 or other refrigerating means, are inserted through a door 0, which swings about hinges II I and is fastened at II2.

An overflow pipe 3 is provided with a hand or automatic valve H4 to drain excess water accumulating in the system from the melting ice.

When the train is to stand for an abnormally long period of time, or when it is desired to precool the train before it starts at the terminal, cakes of ice I09 are transferred from a station truck, not shown, into the section I02 of each car to be refrigerated. The pump corresponding to 40 operates under control of thermostat 50 and pumps water from pipe I04 to an air cooling section corresponding to 43. The water, with heat from the air, returns through pipe I05 and is sprayed over the cakes of ice I09 where it is cooled and drains into section IN. The cycle is repeated as long as ice remains in the sump. Thus the car is maintained at a comfortable temperature until it starts. and is refrigerated by the system as described with respect to Fig. 1.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

1. An air conditioning system for a vehicle comprising a compressor, condensor and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compressor in functional relationship to the motion of the vehicle, a refrigerant expansion means between said condensor and evaporator, and refrigerant throttling means between said evaporator and compressor responsive to condensor conditions.

2. An air conditioning system for a vehicle comprising a compressor, condensor and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compresand means for cooling a holdover with said second evaporator when said compressor attains excess refrigerating capacity.

3. An air conditioning system for a vehicle comprising a compressor, condensor and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compressor in functional relationship to the motion of the vehicle, means for throttling the fiow of evaporated refrigerant from said evaporator to said compressor when said compressor attains excess refrigerating capacity in relation to the refrigerating demands upon said evaporator, a second evaporator connected to said compressor to opcrate at a lower temperature than said first evaporator, a sump containing liquid holdover, means for exchanging heat between holdover and air-to be conditioned, a pump for circulating holdover from said sump to said last named means, said second evaporator being in thermal exchange relationship with the holdover in said sump.

4. An air conditioning system for a vehicle comprising a compressor, condensor and evaporatorin refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compressor in functional relationship to the motion of the vehicle, means for throttling the flow of evaporated refrigerant from said evaporator to said compressor when said compressor attains excess refrigerating capacityin relation to the refrigerating demands upon said evaporator, a second evaporator connected to said compressor to operate at a lower temperature than said first evaporator, a sump containing liquid holdover,

means for exchanging heat between holdover orator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compressor in functional relationship to the motion of the vehicle, means for throttling the flow of evaporated refrigerant from said evaporator to said compressor when said compressor attains excess refrigerating capacity in relation to the refrigerating demands upon said evaporator, a second evaporator connected to said compressor to operate at a lower temperature than said first evaporator, a sump containing liquid holdover, means for exchanging heat between holdover and air to be conditioned, a pump for circulating holdover from said sump to said last named means, said second evaporator being in thermal exchange relationship with the holdover in said sump and means for controlling the operation of said pump in accordance with air conditions.

6. An air conditioning system for a vehicle comprising a compressor, condenser and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange with air to be conditioned for said vehicle, means for driving said compressor in functional relationship to the motion of the vehicle, means for throttling the flow of evaporated refrigerant from said evaporator to said compressor when said compressor attains excess refrigerating, capacity in relation to the refrigerating demands upon said evaporator, a second evaporator connected to said compressor to operate at a lower temperature than said first evaporator, a sump containing liquid holdover, means for exchanging heat between holdover and air to be conditioned, a pump for circulating holdover from said sump to said last named means, said second evaporator being in thermal exchange relationship with the holdover in said sump and means for starting said pump when the refrigerating capacity of said compressor falls below a predetermined limit.

7. Refrigerating apparatus comprising a compressor, condenser and refrigerant evaporating means, an evaporated refrigerant line connecting said evaporating means and the intake of said compressor, a liquid refrigerant line connecting said condenser and said evaporating means, throttling means in said evaporated refrigerant line effective to throttle the flow of refrigerant into said compressor when the refrigerant pressure in said evaporated refrigerant line falls below a predetermined limit and when the refrigerant pressure in said condenser rises above a predetermined limit.

8. An air conditioning system for a vehicle comprising a compressor, condenser and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange relation with air to be conditioned for said vehicle and subjected to variable refrigeration loads in response to extraneous conditions, means for driving said compressor in rator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in .heat exchange relation with air to be conditioned for said vehicle and subjected to variable refrigeration loads in response to extraneous conditions, means for driving said compressor in functional relationship to the varying speeds of the vehicle thereby imposing a variable capacity on said compressor, a refrigerant expansion means between said condenser and evaporator, and refrigerant throttling means between said evaporator and compressor, responsive to air conditions, to balance said variable refrigeration load and said variable compressor capacity.

10. An air conditioning system for a vehicle comprising a compressor, condenser and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange relation with air to be conditioned for said vehicle and subjected to variable refrigeration loads in response to extraneous conditions, means for driving said compressor in functional relationshipto the varying speeds of the vehicle thereby imposing a variable capacity on said compressor, a refrigerant expansion means between said condenser and evaporator, and refrigerant throttling means between said evaporator and compressor limiting the fall in pressure in said evaporator below a predetermined limit to balance said variable refrigeration loads and said variable compressor capacity to maintain the refrigerant pressure in said evaporator sufiiciently high to prevent formation of ice on said evaporator.

11. An air conditioning system for a vehicle comprising a compressor, condenser and evaporator in refrigerant circulating relationship and associated with said vehicle, said evaporator being in heat exchange relation with air to be conditioned, for said vehicle and subjected to variable refrigeration loads in response to extraneous conditions, means for driving said compressor in functional relationship to the varying speeds of the vehicle thereby imposing a variable capacity on said compressor, a refrigerant expansion means between said condenser and evaporator, and refrigerant throttling means between said evaporator and compressor responsive to air conditions in said vehicle limiting the fall in pressure in said evaporator below a predetermined limit to balance said variable refrigeration loads and said variable compressor capacity to maintain comfort conditions in said vehicle, and to maintain the refrigerant pressure in said evaporator sufficiently high to prevent formation of ice on said evaporator.

12. An air conditioning system for-,a vehicle comprising a mechanical refrigerating system operated by power derived from a live axle, means for thermally contacting air for a compart-- ment of said car'and for thermally contacting a holdover with the cooling portion of said mechanical refrigerating system, an ice bunker on said vehicle, and means for cooling said holdover and for cooling air for said compartment by ice in said bunker to augment the refrigeration produced by said mechanical refrigerating system.

13. In combination with a vehicle having a live axle, an air conditioning system for a passenger compartment of said vehicle comprising a mechanical refrigerating system producing refrigeration derived from power from said axle, holdover cooling means cooperating with said mechanical refrigerating system and refrigerated compartment and for coolingsaid holdover when said vehicle is standing and when said holdover lacks suflicient capacity to cool the air.

14. In combination with a vehicle having a live axle, means for conditioning the air for a' passenger compartment of said vehicle comprising a mechanical refrigerating system for producing refrigeration derived from power supplied by said axle. holdover cooling means cooperating with said mechanical refrigerating system and refrigerated by said mechanical refrigerating,

system when said mechanical refrigerating system has excess capacity, and means for providing stand-by refrigeration supplemental to the refrigeration produced by the axle for cooling air for .said compartment, said last named means serving to cool said holdover so as to increase 10 the holdover capacity thereof.

ROBERT R. CANDOR.

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