US2887853A

US2887853A - Temperature control systems for railway refrigerator cars or the like

Info

Publication number: US2887853A
Application number: US657840A
Authority: US
Inventors: Talmey Paul
Original assignee: General American Transportation Corp
Current assignee: General American Transportation Corp
Priority date: 1957-05-08
Filing date: 1957-05-08
Publication date: 1959-05-26
Anticipated expiration: 1976-05-26

Description

5 Sheets-Sheet 1 May 26, 1959 P. TALM'EY E TEMPERATURE coNTEoL sYsTEMs FOR RAILWAY REFRIGERATOR CARS, 0R THE LIKE FiledA day a. 1957 INVENTQR Pau/ a/mey May 26, 1959' P. TALMEY TEMPERATURE CONTROL SYSTEMS FOR RAILWAY REFRIGERATOR CARS, 0R THE LIKE 3 Sheets-Sheet 2 INVENT-OR. Paul Ta/maey Filed May 8, 195'? EG mmm wm ESG S8 Pau/ a/mey V5 Sheets-Sheet 3 mmws ' vl-ALMEY TEMPERATURE CONTROL SYSTEMS FORRAILWAY' REFRIGERATOR CARS, OR THE LIKE EES Em S wcm Y @im n Sm May 2,6, 1959 Filed Hay 8. 1957 United States Patent O TEMPERATURE CONTROL SYSTEMS FOR RAIL- WAY REFRIGERATOR CARS OR THE LIKE Paul Talmey, Barrington, Ill., assignor to General American Transportation Corporation, Chicago, Ill., a cor poration of New York vApplication May 8, 1957, Serial No. 657,840

19 Claims. (Cl. 62-160) The present invention relates to railway refrigerator cars, or the like, and more particularly to temperature control systems for such cars.

It is a general object of the invention to provide in a railway refrigerator car, improved apparatus that is selectively operative to heat and to cool the lading compartment of the car in accordance with a set desired temperature of the circulated storage air therein and dependent upon the temperature of the outside air, whereby the apparatus automatically accommodates itself to the desired direction of heat transfer between the storage air and the outside air while the car is in transit.

Another object of the invention is to provide in a refrigerator car, improved apparatus of the character described that operates entirely upon a refrigerating cycle employing a mechanical refrigerating machine, wherein both the heating function and the cooling function are selectively eiected by the refrigerating machine.

Another object of the invention is to provide in a railway refrigerator car, a temperature control system of the character described, wherein the incorporated refrigerating machine is of the compressor-condenserevaporator type including a heat exchanger that is operatively associated with the circulated storage air in the lading compartment, wherein hot compressed gaseous refrigerant is supplied to the heat exchanger to effect the heating function and liquid refrigerant is evaporated in the heat exchanger to effect the cooling function.

Another object of the invention is to provide in a railway refrigerator car, a temperature control system of the character described, wherein the incorporated refrigerating machine is selectively operative upon a heat pump cycle, so that a first heat exchanger operatively associated with the circulated storage air in the lading compartment is selectively heated and cooled as required and so that a second heat exchanger operatively associated with the outside air is selectively cooled and heated as required.

A further object of the invention is to provide a temperature control system comprising heat exchange apparatus that is operated by an associated internal combustion engine and that is operatively associated with a medium that is to be selectively heated and cooled, and incorporating an improved thermostatic control arrangement for selectively governing the heating function and the coolingfunction of the apparatus and also for selectively governing the operating speed of the engine in order selectively to establish the rate of heat transfer of the heat exchanger in either its heating function or its cooling function.

A further object of the invention is to provide a temperature control system of the character noted, wherein the engine is operated at its low speed in alternate heating and cooling functions of the apparatus in the normal cycle of operation thereof, and wherein the engine is operated at its high speed in either the heating function or the cooling function of the apparatus in the corresponding abnormal cycle of operation thereof, and where- LICC in the low speed of the engine is substantially the idling speed thereof and the high speed of the engine is substantially greater than the idling speed thereof, whereby the normal cycle of the apparatus in either its heating function or its cooling function is carried out at the low speed of the engine and with a corresponding great economy in the utilization of fuel by the engine.

A still further object of the invention is to provide a temperature control system of the character described, wherein the thermostatic control arrangement mentioned comprises thermostatic mechanism that is governed by the temperature of the medium and that is selectively settable to `establish a desired temperature thereof, wherein the thermostatic mechanism is selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above the set desired temperature and selectively operative into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below the primary high temperature, and wherein the heating function and the cooling function of the apparatus are correspondingly set in response to respective low and high temperatures, and wherein the low speed operation and the high speed operation of the engine are correspondingly set in response to respective primary and secondary temperatures, so that the apparatus operates alternately in its heating function and in its cooling function, and so that the engine operates alternately at its low speed and at its high speed.

Further features of the invention pertain tothe particular arrangement of the elements of the temperature control system and of the component parts of the railway refrigerator car, whereby the above-outlined and additional operating features thereof are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the acv companying drawings, in which:

Figure 1 is a diagrammatic illustration of a temperature control system, embodying the present invention, and adapted for incorporation in a railway refrigerator car;

Fig. 2 is a schematic vertical sectional view of the body of a railway refrigerator car, embodying the present invention, and incorporating the temperature control system shown in Fig. l;

Fig. 3 is a diagrammatic illustration of a modiiied form of the temperature control system; and

Fig. 4 is a schematic illustration of a modied form of thermostatic mechanism that may be incorporated in the temperature control system of Fig. 3.

Referring now to Fig. 1, the temperature control system `there illustrated and embodying the features of the present invention comprises a mechanical refrigerating machine including a compressor 10, a condenser 11, a receiver 12, a heat exchanger 13 and a heat interchanger 14. The compressor 10 is of any suitable type, the inlet thereof being connected to a suction conduit 15 and the outlet thereof being connected to a compression conduit 16. The compression conduit 16 is connected to the inlet of the condenser 11 via an electromagnetic valve V1 that is biased into its closed position and operated into its open position in response to energization of its associated solenoid S1. The outlet of the condenser 11 is connected via a conduit 17 to the inlet of the receiver 12; the `outlet of the receiver 12 is connected by a conduit 18 to the inlet of the heat interchanger 14; the outlet of the heat interchanger 14 is connected by a conduit 19 to the inlet of the heat exchanger 13; the outlet of the heat exchanger 13 is connected by a conduit 20 to the inlet of the jacket of the heat interchanger 14; and the outlet of the jacket of the heat interchanger 14 is connected to the suction conduit 15. Also, the compression conduit 16 and the conduit 17 are interconnected by an electromagnetic valve V2 that is biased into its open position and operated into its closed position in response to energization of its associated solenoid S2. The conduit 19 includes an expansion valve 21 of any suitable type that is provided with a thermal responsive element 21a operatively associated with the heat exchanger 13; and a conduit 22 is arranged in bypassing relation with respect to the expansion valve 21 between the conduit 19 and the inlet of the heat exchanger 13; which conduit 22 includes an electromagnetic valve V3 that is biased into its open position and operated into its closed position in response to energization of its associated solenoid S3. Also, the refrigerating machine contains a suitable refrigerant, such, for example, as Freon F12. A fan 23 is operatively associated with the condenser 11 and driven by an associated electric motor 24; and a fan 25 is operatively associated with the heat exchanger 13 and driven by an associated electric motor 26.

The refrigerating machine is operative to supply heat to the heat exchanger 13 when the solenoids S1, S2 and S3 are deenergized; and at this time, when the compressor is operated, compressed gaseous refrigerant is supplied to the compression conduit 16 and passes via the valve V2 in its open position around the condenser 11 into the conduit 17 and thence into the receiver 12. The hot cornpressed gaseous refrigerant then proceeds via the conduit 18, through the heat interchanger 14, and via the conduit 19 through the valve V3 in its open position into the conduit 22 and thence into the heat exchanger 13. From the heat exchanger 13 the hot compressed gaseous refrigerant passes into the conduit and thus through the jacket of the heat interchanger 14 into the suction conduit 15 and thence back into the compressor 10. The work of compression of the compressor 10 is thus transferred to the heat exchanger 13 and thence to the medium circulated thereover to effect heating thereof.

The refrigerating machine is operative to extract heat from the heat exchanger 13 when the solenoids S1, S2 and S3 are energized; and at this time, when the compressor 10 is operated, compressed gaseous refrigerant is supplied to the compression conduit 16 and passes via the valve V1 in its open position into the condenser 11, wherein it is cooled and liquied. The liquid refrigerant passes from the condenser 11 via the conduit 17 into the receiver 12. The liquid refrigerant then proceeds via the conduit 18, through the heat interchanger 14 into the conduit 19. From the conduit 19, the liquid refrigerant passes through the expansion valve `21 into the inlet of the heat exchanger 13, wherein the liquid refrigerant is vaporized and then passes via the conduit 20 through the jacket of the heat interchanger 14 into the suction conduit 15 and thence back into the compressor 10. In the heat interchanger 14, some heat is extracted from the liquid refrigerant that is conducted from the conduit 18 into the conduit 19 by the expanded gaseous refrigerant that is conducted from the conduit 20 to the suction conduit 15. In the operation of the refrigerating machine, heat is extracted from the medium circulated over the heat exchanger 13 effecting cooling thereof while heat is supplied to the medium circulated over the condenser 11 effecting heating thereof.

In view of the foregoing, it will be understood that in order to convert the cycle of the refrigerating machine from its heating phase to its cooling phase, it is only necessary to effect the energization of the solenoids S1, S2 and S3; and in order to return the cycle of the refrigerating machine to its heating phase, it is only necessary to effect the deenergization of the solenoids S1, S2 and S3. Accordingly, the heating phase and the cooling phase of the refrigerating machine may be selected, as desired, by

4 the corresponding deenergization and energization of the solenoids S1, S2 and S3.

Also the temperature control system comprises an internal combustion engine 27 that is provided with an operating shaft 28 that is directly connected to the rotary element of the compressor 10, as well as to starter mechanism 29. Preferably, the engine 27 is of the pistontype (4 cycle-2 cylinder) operated by propane and having a rating of about 1l B.h.p. at 2200 r.p.m. The engine 27 is provided with an intake manifold 30 and an exhaust manifold 31; the intake manifold 30 communicates with a carburetor 32 that is connected to an air inlet structure 33 communicating with the outside air; and the exhaust manifold 31 communicates with a blower 54 that is connected to an exhaust gas structure 35 communicating with the outside air. Also the engine 27 comprises an ignition system indicated at 36; and the carburetor 32 is connected to a fuel control valve 37 that is connected, in turn, to a fuel line 38 extending a liquid fuel vsupply tank, preferably propane, as previously noted. The starter mechanism 29 is also provided with a starter shaft 39 and a control shaft 40, the starter shaft 39 being connected to the rotor of an electric starter motor 41 and the control shaft 40 being connected to a speedresponsive device 42. The fuel control valve 37 is of the two-position type including a slow position effecting operation of the engine 27 at a low speed and a fast position effecting operation of the engine 27 at a fast speed. For example: in the slow position of the fuel control valve 37, the fuel supplied to the carburetor 32 may be such as to operate the engine 27 at its low or idling speed of about 1000 to 1200 rpm.; and in the fast position of the fuel control valve 37, the fuel supplied to the carburetor 32 may be such as to operate the engine 27 at its high or normal operating speed of about 2200 r.p.m. The fuel control valve 37 is selectively operative between its slow and fast positions by a pivotally mounted control lever 43 that is, in turn, selectively operative between corresponding slow and fast positions as determined by two cooperating and corresponding stops 45 and 46. Specifically, the control lever 43 is biased into cooperative engagement with the slow stop 45 by a coil spring 47 and is operated against the spring 47 into cooperative engagement with the fast stop 46 by an armature 48 that is provided with an associated ysolenoid 49. Accordingly, when the solenoid 49 is deenergized, the control lever 43 is moved by the spring 47 into engagement with the slow stop 45; and when the `solenoid 49 is energized, the armature 48 moves the control lever 43 against the spring 47 into cooperative engagement with the fast stop 46. When the engine 27 is operated at its low speed, the compressor 10 is correspondingly operated at its low speed, so that it circulates a relatively small quantity of refrigerant per unit time, thereby establishing a corresponding relatively low rate of heat transfer of the heat exchanger 13, either as a heater or as a cooler, depending upon the phase of the cycle of the refrigerating machine, as established by the position of the valves V1, V2 and V3, as previously explained. On the other hand, when the engine 27 is operated at its high lspeed, the compressor 10 is correspondingly operated at its high speed, so that it circulates a relatively large quantity of refrigerant per unit time, thereby establishing a corresponding relatively high rate of heat transfer of the heat exchanger 13, either as a heater or as a cooler, depending upon the phase of the cycle of the refrigerating machine, as established by the position of the valves V1, V2 and V3, as previously explained. Moreover, the load that is imposed upon the engine 27, either at its low speed or at its high speed, is not in excess of about one-half of the available horsepower thereof at the corresponding operating speed.

Further the temperature control system comprises a primary thermostat 50 and a secondary thermostat 60, both arranged in heat exchange relation with the current of air after it iscirculated over the heat exchanger 13, so thatveach of the

thermostats

50 and 60 is responsive to the temperature of this medium and governed in accordance with the temperature thereof. As illustrated, the primary thermostat 50 comprises a movable bimetallic element 51, an associated stationary element 52 and an electric heater 53 operatively associated with the bimetallic element 51. carries a contact that cooperates with an associated contact carried by a threaded member 54 supported by the stationary element 52, the member 54 being adjustable by an associated part 55, so as to accommodate the setting or establishing of a desired temperature bythe primary thermostat 50. As illustrated, the secondary thermostat 60 comprises a thermal bulb 61 connected by a tube 62 to a resilient bellows 63; these elements containing a liuid that is temperature-responsive, such, for example, as chlorinated diphenol; whereby the bellows 63 is expanded and contracted respectively in response `to an increase in the temperature and in response to a decrease in the temperature to which the thermal bulb 61 is subjected. In turn, the bellows 63 carries an actuating member 65 that cooperates with a resilient control spring 66 that carries two contacts that respectively cooperate with two other contacts that are respectively carried by

twomembers

67 and 68, that are, in turn, carried by two supports 69 and 70. The

members

67 and 68 are individually adjustable by respectively associated parts 71 and 72, so as to accommodate the setting or establishing of a desired temperature by the secondary thermot stat 60.

Reconsidering the thermostatic mechanism collectively, the primary thermostat 50 is set to establish a desired temperature of the medium circulated over the heat exchanger 13, and similarly the secondary thermostat 60 is set to establish the Isame desired temperature of the medium circulated over the heat exchanger 13. The primary thermostat 50 is arranged to operate between its open position (when it is hot) and its closed position (when it is cold) in response to a temperature spread of about 2 F.; whereby the primary thermostat 50 is selectively operative into its primary high or open position in response to a primary high temperature disposed about 1 F. above the set temperature and into its primary low or closed position in response to a primary low temperature disposed about 1 F. below the set temperature. The Isecondary thermostat 60 is arranged to operate between its position closing the contacts between the spring 66 and the member 67 (when it is hot) and its position closing the contacts between the spring 66 and the member 68 (when it is cold) in response to a temperature spread lof about 4 F.; whereby the secondary thermostat 60 is selectively operative into its second` ary high position closing the contacts between the elements 66 and 67 in response to a secondary high temperature disposed about 2 F. above the set temperature and into its secondary low position closing the contacts between the elements 66 and 68 in response to a secondary low temperature disposed about 2 F. below the set temperature.

Further, the temperature control system comprises a control switch 80 having stop and run positions and including a contact wiper `81 and two cooperating contact segments 82 and 83, the contact segment 82 being connected to the positive terminal of an electric storage battery 84, the negative terminal of which is connected to a ground conductor 85, and the contact segment 83 being connected to a power supply bus 86. Also, the system comprises a contact bridging member 87 operatively connected to the speed responsive device 42, an electric drive motor 88' operatively connected to the blower 34 and a cycle control relay 90, as well as a speed control relay 91. The cycle control relay 90 comprises an armature 92, an operating winding 93 and a contact bridging member 94 governed by the armature" 92; while the speed con- The bimetallic element 51 6 trol relay 91 comprises the solenoid 49 and the cooperating armature 48, previously described.

The supply bus 86 is further connected to one terminal of the starter motor 41, and the other terminal of the start'er/ motor 41 is connected by a conductor 95 to the lower back contact of the pair associated with the contact bridging member 87, the upper back contact of this pair being connected to the ground conductor 85. The upper front contact associated with the contact bridging member 87 is connected to the supply bus 86, and the lower front contact of this pair is connected to a conductor 96. The

electric motors

24, 26 and 88 are connected in parallel relationship between the supply bus 86 and the ground conductor 85. The conductor 96 is connected to one contact of the pair controlled by the bridging member 94; and the other contact of this pair is connected to a conductor 97. The solenoids S1, S2 and S3 are connected in parallel relation between the conductor 97 and the ground conductor 85. In the primary thermostat 50, the bimetallic element 51 is connected to the ground conductor and also to one terminal of the electric heater '53, the other terminal of the electric heater 53 being connected to a conductor 99'; while the stationary element 52 is connected to a conductor 99; and a current limiting resistor 98 is bridged between the conductors 99' and 99. In the secondary thermostat 60, the resilient spring 66 is connected to a conductor 96'; while the elements 69 and 70 are connected in parallel relation to the conductor 96. The solenoid of the speed control relay 91 is connected between the conductor 9 6 and the ground conductor 85; and the operating winding 93 of the cycle control relay 90 is connected between the conductors 96 and 99. Finally, a frost switch 13A is operatively associated with the heat exchanger 13 and provided withra pair of switch springs respectively connected to the ground conductor 85 and to the conductor 99. In the arrangement, the frost switch 13A is normally biased into its open position and is operated into its closed position in response to the accumulation of a predetermined amount of frost upon the heat exchanger 13.

Referring now to Fig. 2, the temperature control system previously described in conjunction with Fig. 1 may be incorporated in-a railway refrigerator car 200 that comprises a body 201 that is carried by an underframe, not shown; which underframe carries a truck provided with track-engaging wheels. The body 201 comprises structure dening a lrelatively small machinery compartment 202 and a relatively large lading compartment 203; the structure including heat insulating walls enclosing the lading compartment 203 and defining the substantially box-like configuration thereof. More particularly, the wall structure of the body 201 is preferably of the construction and arrangement of that disclosed in U.S. Patent No. 2,642,818, granted on June 23, 1953, to Paul Talmey; whereby the lading compartment 203 is bounded by a heat insulating lining including a tioor, a ceiling, a pair of opposed end walls and a pair of opposed side walls. In the arrangement, the intermediate portions of the side walls are respectively provided with door pairs affording selective access to the lading compartment 203, the door pair provided in one of the sidewalls being indicated at 204a--204b. In this construction, as disclosed in the Talmey patent, the walls of the heat insulating lining bounding the lading compartment 203 comprise insulation sandwiches, each including two outer sheets of plywood and an intermediate layer of foamed polystyrene intimately bonded thereto.

In the arrangement, the heat exchanger 13 is disposed in the lading compartment 203 and the fan 25 circulates the storage air in the lading compartment over the heat exchanger 13. Also the primary thermostat 50 and the secondary thermostat 60 are arranged in the lading compartment 203 in heat exchange relation with the storage air circulated therein; and likewise, the heat interchanger 14 may be arranged in the lading compartment 203. On the other hand, the engine 27, the compressor 10, the condenser 11, the receiver 12, the blower 34 and the fan 23 are arranged in the machinery compartment 202. The side wall, not shown, of the body 201 is provided with a doorway and a cooperating door affording access to the machinery compartment 202; which door, not shown, in its closed position, accommodates the passage of outside air into the air inlet structure 33 operatively associated with the engine 27 and into an inlet air manifold 205 operatively associated with the fan 23. As previously noted, the blower 34 removes the exhaust gases from the engine 27 and discharges the same to the exhaust structure 35 that may extend through the roof of the body 201 into communication with the outside. Also an outlet air manifold 206 cooperates with the condenser 11 and is connected to air outlet structure 207 that may extend through the roof of the body 201 into communication with the outside. Accordingly, it will be understood that the operation of the blower 34 effects the delivery of outside air to the engine 27, as well as the removal of exhaust gases therefrom and the discharge of the exhaust gases back to the outside. Similarly, the operation of the fan 23 effects the circulation of outside air through the manifold 205 and then over the condenser 11 into the manifold 206 and thence back to the outside.

In this case, the ranges of the primary thermostat 50 and the secondary thermostat 60 should embrace the normal operating temperature range (about F. to +45 F.) of the lading compartment 203 of the refrigerator car 200.

Again referring to Fig. l and considering the mode of operation of the refrigerating machine in conjunction with its control circuit, operation of the engine 27 is initiated in response to operation of the control switch 80 from its stop position into its run position, whereby the wiper 81 bridges the conducting segments 82 and 83 connecting power to the supply bus 86, so that the blower motor 88 and the

fan motors

24 and 26 are operated. Operation of the blower motor 88 effects. the supply of outside air to the engine 27; operation of the fan motor 24 effects the circulation of outside air over the condenser 11; and operation of the fan motor 26 effects the circulation of storage air in the lading compartment 203 over the heat exchanger 13. At this time, it may be assumed that the storage air is hot so that the primary thermostat 50 occupies its open position and so that the secondary thermotat 60 occupies its position closing the contacts between the elements 66 and 67. Also, it may be assumed that no frost is accumulated upon the heat exchanger 13, so that the frost switch 13A occupies its open position. The connection of power to the supply bus 86 energizes the ignition system 36 of the engine 27 and completes a circuit for operating the starter motor 41. The last-mentioned circuit includes the closed back contacts associated with the contact bridging member 87, since the speedresponsive device 42 is at rest. Upon operating, the starter motor 41 rotates the starter shaft 39 causing the starter mechanism .29 to rotate the operating shaft 28 and the control shaft 40. Since the ignition system 36 is energized, it may be assumed that the engine 27 is started, and then runs to effect the supply of power to the operating shaft 28 in order to cause operation of the cornpressor 10. Also, it may bev assumed that the engine 27 rotates the operating shaft 28 at a higher speed than does the starter motor 41; whereby the speed responsive device 42 is governed to operate the contact bridging member 87 so as to open the associated back contacts and to close the associated front contacts. Opening of the back contacts associated with the bridging member 87 interrupts the circuit for operating the starter motor 41; whereby it may be assumed that rotation of the drive shaft 28 is continued by the operating internal combustion engine 27. Closing of the front contacts associated with the bridging member 87 connects the supply bus 86 to the conductor 96, thereby to prepare the cycle control relay 90, the speed control relay 91 and the solenoids S1, S2 and S3, depending upon the conditions of the primary thermostat 50 and the secondary thermostat 60, as explained more fully below.

ln the present example, a priming circuit is completed for energizing the winding 93 of thc cycle control relay in series with the current limiting resistor 98 and the electric heater 53, whereby the cycle control relay 90 is not operated by virtue of the inclusion of the high resistance of the current limiting resistor in the energizing circuit; however, the electric heater 53 develops a small amount of heat that influences the bimetallic element 51 of the primary thermostat 50 so as to prevent rapid hunting thereof when the temperature in the lading compartment 203 is subsequently lowered substantially to the preset temperature, as explained more fully subsequently. Accordingly, the cycle control relay 90 is retained in its restored position so that the bridging member 94 retains the connection between the conductor 96 and the conducort 97; whereby the applicaiton of power to the conductor 97 completes parallel circuits for energizing the solenoids S1, S2 an( S3. Thus the valve V1 is operated into its open position and the valves V2 and V3 are operated into their closed position; whereby the cycle of the refrigerating machine is converted from its heating phase to its cooling phase, as previously explained. Also, in the present example, the conductor 96 is connected to the conductor 96 via the closed contacts between the members 66 and 67 of the secondary thermostat 60; whereby a circuit is completed for emergizing the solenoid 49 of the speed control relay 91 so that the armature 48 operates the control member 43 from its slow position into its fast position in order correspondingly to operate the fuel control valve 37 from its slow position into its high position. Accordingly, the fuel supplied from the fuel line 38 via the fuel control valve 37 to the carburetor 32 is increased changing the speed of the internal combastion engine 27 from its low speed to its high speed, in order to bring about a corresponding increase inthe speed of the operation of the compressor 10, with the result that the cooling rate of the heat exchanger 13 is changed from its low heat transfer rate to its high transfer rate, as previously explained.

The cooling of the heat exchanger 13 proceeds at the high rate of heat transfer and subsequently it may be assumed that the temperature of the lading compartment 203 is lowered from its secondary high temperature toward its primary high temperature with respect to the preset temperature, whereby the secondary thermostat 60 is controlled to effect opening of the contacts between the members 66 and 67 thereof so as to interrupt the circuit for energizing the solenoid 49 of the speed control relay 91; whereby the armature 48 is released operating the control member 43 from its fast position back into its slow position in order correspondingly to operate the fuel control valve 37 and resulting in the reduction of the speed of the internal combustion engine 27 from its high speed back to its low speed. Accordingly, the speed of operation of the compressor 10 is correspondingly re-v duced so as to reduce the rate of heat transfer of the heat exchanger 13, with the result that further cooling of the air circulated through the lading compartment 203 proceedsat the low rate of heat transfer.

The cooling of the heat exchanger 13 proceeds at the low rate of heat transfer and subsequently it may be assumed that the temperature of the lading compartment 203 is lowered into its primary low temperature with respect to the preset temperature; whereby the primary thermostat 50 is controlled to close the contacts between the

elements

51 and 54 thereof; whereby a path is completed for short-circuiting the electric heater 53 and the current limiting resistor 98, so that the current traversing the winding 93 of the cycle control relay 90 is materially increased effecting operation thereof, with the result that 2 9 the amature 92 is attractedoperting the-contact bridglng member 94 into its open position, so as to disconnect the .conductor 96 from the conductor 97, thereby deenergizing the solenods S1, S2 and S3. Accordingly, the valve V1 is returned into its closed position and the valves and V3 are returned intok their open positions; whereby the cycle of the refrigerating machine is controlled, returning the same from its cooling phase back ltinto 4its heating phase, as previously explained. At this time, the internal combustion engine 27 is running at its low speed eifecting corresponding operation of the compressor at its low speed, with the result that heat is supplied to the heat exchanger 13 at the low rate of heat transfer eiecting corresponding heating of the air circulated in the lading compartment 203.

lThe heating of the heat exchanger 13 proceeds at the low rate of heat transfer and subsequently it may be assumed that the temperature of the lading compartment 203V is raised into its primary high temperature with respect to the preset temperature, whereby the primary thermostat 50 is controlled to open the contacts between the elements v51 and 54 thereof; whereby the previouslymentioned path for short-circuiting the electric heater 53 and the current limiting resistor 98 is interrupted, with the result that these elements are again inserted in the circuitfor energizing the winding 93 of the cycle control relay 90, so that the cycle control relay 90 is restored in order that the contact bridging member 94 recloses the associated contacts reconnecting the conductor 94 to the conductor 97; whereby the solenoids S1, S2 and S3 are again energized. Accordingly, the valve V1 is returned into its open position and the valves V2 and V3 are returned into their closed position; whereby the cycle of the refrigerating machine is controlled, returning the same from its heating phase back into its cooling phase.

The cooling of the heat exchanger 13 proceeds at the low rate of heat transfer and subsequently it may be assumed that the temperature of the lading compartment 203 is lowered into its primary low temperature with respect to the preset temperature; whereby the primary .thermostat 50 is controlled to reclose the contacts between the

elements

51 and 54, whereby the cycle of the refrigerating machine is returned from its cooling phase back into its heating phase, as previously explained.

During the operation of the refrigerating machine, should the temperature in the storage compartment 203 be lowered from its primary low temperature into its secondary low temperature with respect to the preset temperature, the secondary thermostat 60 is operated to close the contacts between the elements 66 and 68 thereof, while the primary thermostat 50 occupies its` position closing the contacts between the

elements

51 and 54 thereof. `In this case, the cycle control relay 90 occupies its -operated position causing the refrigerating machine to operate in its heating phase; and operation of the secondary thermostat 60 into its secondary low position, closes the contacts between the elements 66 and 68 thereolf, so as to complete an alternative connection between the conductors 96 and 96'; whereby the speed control relay 91 is governed to operate the fuel control valve 37 from its slow position into its fast position, with the result that the speed of the internal combustion engine 27 is increased from its low speed to its high speed, effecting corresponding operation of the compressor 10, so that the heat supplied to the heat exchanger 13 proceeds at the high rate.

The heating of the heat exchanger 13 proceeds at the high rate of heat transfer, and subsequently it may be assumed that the temperature of the lading compartment 203 is increased with respect to the preset temperature; whereby the secondary thermostat 60 is operatedto open the contacts between the elements 66 and 68 thereof, with the result that the previously-mentioned alternative circuit for energizing the solenoid 49 is interrupted, so that the speed control relay 91 is restored effecting the returnof the fuel control valve 37 from its fast position back. into its slow position. Accordingly, the speed of the internal combustion engine 27 is returned from its high speed back into its low speed, correspondingly operating the compressor 10, so that the heating of the heat exchanger 13 is returned from its high rate of heat transfer back` into its low rate of heat transfer.

The heating of the heat exchanger 13 proceeds at the low rate of heat transfer, and it may be assumed that subsequently and notwithstanding the heating of the air circulated through the lading compartment 203, the temperature of the circulated air is lowered into its secondary low temperature with respect to the preset temperature thereof, which condition might be encountered when the refrigerator is in transit in an area having an exceedingly low ambient temperature. In this case, the secondary thermostat 60 is again operated into its secondary low position effecting reoperation of the speed control relay 91, with-the result that the fuel control valve 37 is operated from its low position into its high position, bringing about an increase in the speed of operation of the internal combustion engine 27, so that the compressor 10 is correspondingly operated, with the result that the heat is supplied to the heat exchanger 13 at the high rate, as previously explained.

In View of the foregoing, it will be understood that the primary thermostat 50 governs the cycle control relay 90 in order selectively to set the cycle of the refrigerating machine alternately between its heating phase and its cooling phase; whereas the secondary thermostat 60 governs the speed control relay 91 in order selectively to set the speed of the internal combustion engine 27 alternately between its low speed position and its high speed position, so as alternately to set the rate of heat transfer of the heat exchanger 13 between its low heat transfer rate'and its high heat transfer rate.

`This arrangement is very advantageous in that the engine 27 is constantly operated, either at its light or lowspeed 'load or'at itsv heavy or high-speed, thereby greatly reducing the amount of carbon formation therein, with respect to that which is produced therein when it is run under idling condition disconnected from all external loads. Moreover, the light load, either heating or cooling, that is imposed upon the compressor 10 at the low speed thereof does not cause any substantial increase in thefuel consumption of the engine 27 over that which is consumed thereby in an idling operation thereof, when it is disconnected from all external loads; whereby the heating or cooling of the heat exchanger 13 at the corresponding low rates of heat transfer are achieved at substantially no expense with respect to the fuel consump tion of the engine 27, related to the normal fuel consumption thereof when it is running under idling condition. These are inherent operating characteristics of a small internal combustion engine of the character noted, when arranged in the manner described. Furthermore, the rating of the engine 27 is related to the required heating and cooling of the lading compartment 203 of the refrigerator car 200, so that the running of the engine 27 at its low speed is adequate to supply the required heating `(in the heating phase of the refrigerating machine) except under the most adverse winter conditions, and is adequate to supply the required cooling (in the cooling phase of the refrigerating machine) except under the most adverse summer conditions. Accordingly, the high speed operation of the engine 27 is very unusual and occurs only under the most adverse winter condition or under the most adverse summer condition, as noted above; whereby the normal and usual operation of the engine is at low speed, so as to 'achieve the economies and to obtain the advantages explained.

It is also pointed out that this arrangement, wherein the engine 27 is constantly operated alternately lto effect heating and cooling of the lading compartment 203,

-employs a amount of equipment, eliminating the usual clutches, unloader apparatus, etc., thereby materially contributing to simplification of the refrigerating .apparatus and to economy of manufacture and operation thereof, and yachieving low cost in the operation and the maintenance of the engine 27.

During the cycle of operation of the refrigerating machine, should an undue amount of frost accumulate upon the heat exchanger 13, the frost switch 13A is operated frorn its open position into its closed position, completing a direct connection of the Iground conductor 85 to the conductor 99, with the result that the cycle control relay 99 is operated, so as to return the cycle of the refrigerating machine into its heating phase entirely independently of the position of the primary thermostat In other words, the control of the frost switch 13A over-rides the control of the primary thermostat 50. Accordingly, heating of the heat exchanger 13 is effected, with the result that the undesirable frost accumulated thereupon is melted, so as to return the frost switch 13A from its closed position back into its open position. Opening of the frost switch 13A interrupts `the direct connection of the ground conductor 85 to the conductor 99, whereby the control of the cycle relay 90 is returned to the primary thermostat 5i), in an obvious manner.

Referring now to Fig. 3, the modified form of the temperature control system there illustrated, and embodying the features of the present invention, is fundamentally the same as that illustrated in Fig. 1, and corresponding reference numerals -are employed to designate the corresponding elements in Figs. l and 3 of the drawings. More particularly, this system comprises a refrigerating machine that is arranged upon la full heatpump cycle and including a compressor 310, a heat exchanger 311, a receiver 312, a heat exchanger 313, a heat interchanger 314 and an expansion valve 321. In this arrangement, the heat exchanger 311 is disposed in the machinery compartment 202 of the refrigerator car 200 and is termed an outside coil; whereas the heat exchanger 313 is disposed in the lading compartment 203 of the refrigerator car 260 and is termed an inside coil. The compression conduit 316 extending from the compressor 316 is selectively connectible by two electromagnetic `valves V11 and V15 respectively to the inlet of the -outside coil 311 and to the inlet of the inside coil 313; similarly, the conduit 32?. extending from the expansion valve 321 is selectively connectible by two electromagnetic valves V13 `and V17 respectively to the inlet of the inside coil 313 and to the inlet of the outside coil 311. T he suction conduit 315 extending to the compressor 31? is connected via the jacket of the heat exchanger 314 to the conduit 320 that is selectively connectible by two electromagnetic valves V14 and V18 respectively to the outlet of the inside coil 313 and to the outlet of the outside coil 311; and similarly, the conduit 317 extending to the receiver 312 is selectively connectible by two electromagnetic valves V12 and V16 respectively to the outlet of the outside coil 311 and to the outlet of the inside coil 313. The conduit 317 extends to the receiver 312; the receiver 312 is further connected via the conduit 313 to the inlet of the heat interchanger 314; and the heat interchanger 314 is connected by the conduit 319 to the expansion valve 321 that discharges into the conduit 322 as previously noted.

in the arrangement, all of the valves V11 to V18, inclusive, are biased into their closed positions; the Ivalves V11 to V14, inclusive, are operated into their open positions to set the cycle of the refrigerating machine so as to effect heating of the outside coil 311 and cooling of the inside coil 313; and the valves V15 to V18, inclusive are operated into their open positions to set the cycle of the refrigerating machine so as to etect heating of the inside coil 313 and cooling of the outside coil 317. The electromagnetic valves V11 to V18, in-

clusive, are provided with individually associated operating solenoids SV11 to SV18, inclusive; and hereinafter the cycle of the refrigerating machine is related to the effect produced upon the inside coil 313. Accordingly, the refrigerating machine occupies the cooling phase of its cycle when the electromagnetic valves V11 to V14, inclusive, are in their open positions; and the refrigerating machine occupies the heating phase of its cycle when the electromagnetic valves V15 to V17, inclusive, are in their open positions.

Also, the system comprises the cycle control relay 390 that is governed by the primary thermostat 350 and by the frost switch 313A operatively associated with the inside coil 313. In this arrangement, the function of the speed control relay is divided into two parts, so that in fact there are provided a main speed control relay 391 andan auxiliary speed control relay 391A; which are governed by the secondary thermostat 360.

Further, the system comprises the internal combustion engine 327, the carburetor 332, the fuel control valve 337, and the fuel line 338. Further, a D.C. electric generator 501 is directly connected to the operating shaft 328a of the engine 327, and a D.C. electric drive motor 502 is directly connected to the operating shaft 328b of the compressor 310. In the arrangement, the drive motor 502 is of the two-speed type and of any conventional construction, and includes a high speed winding and a low speed winding, not shown, that effect corresponding operations thereof at high speed and at low speed. The main speed control relay 391 governs two contact controlling members 343@ and 343b that have back contacts effecting energization of the low speed winding of the drive motor 502 and front contacts etfecting energization of the high speed winding of the drive' motor 502. The auxiliary speed control relay 391A governs the control lever 343 of the fuel control valve 337, the control lever 343 being operated into 'its slow position when the auxiliary speed control relay 391 is restored and the control lever 343 being operated into its fast position when the auxiliary speed control relay 391 is operated. Also the system comprises two feed buses 515 and 516, as well as a manually operable master switch 517 of the double-throw type, a rectifier 521, and a connected plug 522 that is connectible to an external source of A.C. electric power supply. More particularly, the master switch 517 includes three

blades

518, 519 and 520, the

blades

518 and 519 respectively terminating the feed buses 515 and 516, and the blade 520 -terminating one terminal of the winding of the auxiliary speed control relay 391A, the other terminal of the winding of this relay being connected to the feed bus 515. Also the master switch comprises two upper contacts operatively associated respectively with the

blades

518 and 519 and terminating a 'line connected to the rectifier 5217 and a pair of lower contacts Arespectively associated with the

blades

518 and 519 and terminating respectively the

supply buses

511 and 512. Finally, the master switch 517 includes a lower contact operatively associated with the blade 521 and terminating the conductor 596' that extends to the switch springs 367 and 368 of the secondary thermostat 360, the switch springs 366 of the secondary thermostat 36% being connected to the feed bus 516. Also, the winding of the main speed control relay 391 'is connected between the conductor 396' and the feed bus 515. The cycle control relay 390 includes two contact bridging members 394a and 39411 provided with back contacts controlling the energization of the solenoids SV11 to SV14, inclusive, and front contacts controlling the energization of the solenoids SV15 tov SV18, inclusive.

Considering now the general mode of operation of the temperature control system of Fig. 3, it may be assumed that the master switch 510 occupies its upper position connecting the feed buses 515 and 516 to the output of the rectifier 521 and that the plug 522 is connected to a suitable source of A.C. electric power supply, whereby the D.C. electric power output of the rectifier 521 is connected to the feed buses 515 and 516. This arrangement is normally used when the refrigerator car 200 is on a siding, or the like, lat which commercial A.C. electric power is available. When power is thus connected to the feed buses 515 and 516, the cycle control relay 390 is governed by the primary thermostat 350 and the main speed control relay 391 is governed by the secondary thermostat 360, the controls being essentially the same as those previously explained. For example, assuming that the primary thermostat 350 occupies its primary high position illustrated, the cycle control relay 390 remains in its restored position; whereby the contact bridging members 394e and 394b close the associated back contacts connecting the solenoids SV11 to SV14, inclusive, to the feed conductor 515 rand 516 in order to bring about opening of the valves V11 to V14, inclusive,

. whereby the cycle of the 'refrigerating machine is set into its cooling phase. Further assuming that the secondary thermostat 360 occupies its secondary high position illus-` trated, the main speed control relay 391 is operated; whereby the contact bridging members 343e and 343b connect the high speed winding of the drive motor 502 to the feed buses S15 and 516 so that the drive motor 502 is operated at its high speed eifecting corresponding operation of the compressor 310 so as to set the high rate of cooling of the inside coil 313.

Subsequently, it may be assumed that the secondary thermostat 360 is operated out of its secondary high position; whereby the circuit for energizing the winding of the main speed control relay 391 is interrupted,`caus in-g the latter relay to restore so that the contactbridging members 343m and 343b contact the low speed wind` ing of the drive motor 502 to the feed buses 515 and at its low speed effecting corresponding operation of the compressor 310 with the result that the cooling of the inside coil 313 proceeds at the low rate of heat transfer. Still subsequently, it may be assumed that the primary thermostat 350 is operated from its primary high position into its primary low position so as to effect operation of the cycle control relay 390; whereby the contact bridging members 394e and 394b interrupt the parallel circuits for energizing the solenoids SV11 to SV14, inclusive, and complete the parallel circuits for energizing the solenoids SV15 to SV18, inclusive. Accordingly, the valves V11 to V14, inclusive, are closed and the valves V15 to V18 are opened, thereby to set the cycle of the refrigerating machine into its heating phase. At any time, in the event the secondary thermostat 360 is operated into its secondary low position, an alternative circuit is completed for operating the main speed control relay 391; whereby the contact bridging members 343e and 343b open the circuit for energizing the low speed winding of the drive motor 502 and close the circuit for energizing the high speed winding thereof, so as to effect high speed operation of the compressor 310 and the consequent heating of the inside coil 313 at the high rate.

In view of the foregoing, it will be understood that the cycle of the refrigeratng machine is selectively set by the cycle control relay 390 under the control of the primary thermostat 350, whereby the cycle of the refrigerating machine is alternately set into its heating phase and into its cooling phase. Similarly, it Will be understood that the speed of the drive motor 502 and consequently the rate of heat transfer of the inside coil 313 is selectively set by the main speed control relay 391 under the control of the secondary thermostat 360; whereby the inside coil 313 is alternatively set to effect heat rtransfer at the low rate and yat the high rate. Of course, the position of the cycle relay 390 is also governed by the over-riding control of the frost switch 313A in the event of an accumulation of an undue amount of frost upon the inside coil 313, in the manner previously explained.

Now. assume that `the master switch'517 occupies Jits lower position connecting the feed buses 515 and 516 to the

supply buses

511 and 512 and also connecting'one terminal of the winding of the auxiliary speed control relay 391A to the conductor 396'; whereby the winding of the auxiliary speedcontrol relay 391A is connected in parallel relationship with the winding of the main speedcontrol relay 391. Also assume that the generator 501 is running by virtue of operation of the internal combustion engine 3.27; which arrangement is normally used when the refrigerator car 201 is in transit. Fundamentally the mode of operation of the refrigerating machine n this case is the same as that described above with respect to the controls eifected by the cycle control relay 390 and by the main speed control relay 391; however, in this case, the auxiliary speed control relay 391A is governed simultaneously with the main speed control relay391 by the secondary thermostat 360. Accordingly, when the secondary thermostat 360 occupies either of its extreme positions, its secondary high temperature position or its secondary low temperature position, the auxiliary speed control relay 391A is operated, along with the operation of the main speed control relay 391. On the other hand, when the secondary thermostat 360 occupies other than yits two extreme positions noted, the auxiliary speed control relay 391A -is restored, along with the main speed control relay 391. l When `the auxiliary speed control relay 391A occupies its restored position, the fuel control valve 337 is operated into its slow position; and when the auxiliary speed control relay 391A occupies its operated position, the fuel control valve 337 is operated into its fast position; whereby the speed of the internal combustionengine 327 is correspondingly set at its low speed and at its high speed. Accordingly, when the main speed control relay 391 restores to impose the low speed load of the drive motor 502 upon the generator 501, the auxiliary speed control relay 391A restores to operate the engine 327 at its low speed. On the other hand, when the main speed control relay 391 operates to impose the high speed load of the drive motor- 502 upon the lgenerator 501, the auxiliary speed i control relay 391A operates to operate the engine 327 at itshigh speed. `In the arrangement, it is preferred that the generator 501 be Wound to supply both the low speed load and the high speed load at substantially the samevoltage; which arrangement may be readily accomplished by the utilization of a compound wound machine, including a substantial series related eld coil, indicated at 501a. w l

In view of the foregoing, it will be understood that in either positionl of the master switch 517, the secondary thermostat 360 governs the main speed control relay 391 selectively to set the speed of the drive motor 502 so as correspondingly to control the compressor 310 and consequently the rate of heat transfer of -the inside coil 313.

Also Ain the lower position of the master switch 517, the

secondary thermostat-360l governs the auxiliary speed control relay 391A so as to match the speed of the internal combustion engine 327 to the speed of the drive motor 502.` Accordingly,y it will be understood that the fundamental mode of operation ofthe temperature control system of Fig. 3 is the same as that of the temperature control system of Fig. 3 is the same as that of the temperature control system of Fig. 1, the system of Fig. 3 being the electrical equivalent of the mechanical arrangement of Fig. l.

Referring now to Fig. 4, a modified form of the thermostat 600 is illustrated that may be directly substituted into the temperature control system of Fig. 3 for both the primary thermostat 350 and the secondary thermostat 360. More specifically, the thermostat 360 comprises a combination primary-secondary thermostat'and includes' springs 604 and 605. The switch vspring 604 cooperates.

with a switch spring 606, while the switch spring 605 cooperates with a switch spring 607. Also, a spring 608 is provided that carries a member 609 arranged in cooperating relation with the switch spring 607. Moreover, a switch spring 610 is provided that carries a member 611 that also cooperates with the switch spring 605; which switch spring 610 further cooperates with a switch spring 612. The members 602, '603, 609 and 611 carry manually adjustable knobs for the purpose of selectively setting the various temperatures involved at which the controls are effected, as explained more fully below. W'hen the thermostat 600 occupies its secondary high temperature position, the bimetallic element 601 engages the member 602 causing the switch springs 604 to engage the switch spring 606 to close the feed bus 516 to the conductor 396 for the purpose of operating the main speed control relay 391 (and perhaps also the auxiliary speed control relay 391A). When the thermostat 600 is subsequently operated into its primary high temperature position, the bimetallic element 601 disengages the member 602, causing the switch springs 604 to disengage the switch spring 606 to open the feed bus 516 from the conductor 396' for the purpose of restoring the main speed control relay 391 (and perhaps also the auxiliary speed' control relay 391A). Still subsequently, when the thermostat 600 is operated into its primary low temperature position, the birnetallic element 601 engages the member k602 causing the switch spring 605 to engage the switch spring 607 to close the feed 'bus 516 to the conductor 397 for the purpose of operating the cycle control relay 390. Still subsequently, when the thermostat 600 is operated into its secondary low temperature position, the bimetallic element 601 urges the member 603 to cause the switch spring 605 to engage thevmember 611 so as to cause the switch spring 610 to engage the switch spring 612 to close the feed bus 516 to the conductor 396 for the purpose of operating the main speed control relay 391 (and perhaps also the auxiliary speed control relay 391A).

In view of the foregoing, it will be understood that the subsequent return movement of the bimetallic element 601 from its secondary low temperature position and ultimately into its secondary high temperature position sequentially operates the switch spring sets 610--612, 605-607 and 604-606 in the reverse order, in an obvious manner. By proper adjustment of the member 602, the secondary high temperature may be selectively set; by proper adjustment of the members 603 and 609, the primary high temperature and th-e primary low temperature may be selectively set; and by proper adjustment of the member 611 the secondary low temperature may be selectively set. These adjustments not only establish the temperatures noted, but they also set the spread of the primary temperature range and the spread of the secondary temperature range on either side of the primary temperature range.

In view of the foregoing, it will be appreciated that both the primary thermostatic control function and the secondary thermostatic control function may be incorporated in a combined thermostatic mechanism; and morehydraulic or pneumatic form; whereby the relays referred.

to may be of corresponding mechanical form, instead of electrical form.

In view of the foregoing, it is apparent that/there has been provided an improved temperature control system for a railway refrigerator car, or the like; which system is also of general utility in any lheating-cooling arrangement;v Also, the temperature lcontrol system incorporates an improved arrangement for effecting the heating function and the cooling function, as well as the rate of heat transfer in either the heating function or the cooling function, in an exceedingly simple and economical manner.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that various modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

l. In a railway refrigerator car including structure delining a heat-insulating lading compartment and an adjacent machinery compartment, the combination comprising first and second heat exchangers respectively arranged in said lading compartment and in said machinery compartment, a compressor arranged in said machinery compartment, a two-position valve mechanism selectively operative between heating and cooling positions, said valve mechanism in its heating position completing a first refrigerant circuit including said compressor and said first heat exchanger and in which compressed gaseous refrigerant is supplied to said first heat exchanger, said valve mechanism in its cooling position completing a second refrigerant circuit including said compressor and both of said heat exchangers and in which liquid refrigerant is expanded in said first heat exchanger and compressed gaseous refrigerant is supplied to said second heat exchanger, an internal combustion engine arranged in said machinery compartment and operatively associated with said compressor and selectively operative at low and high speeds, whereby operation of said engine at its low speed effects low speed operation of said compressor to establish a low rate of heat transfer of said first heat exchanger said operation of said engine at its high speed effects high speed operation of said compressor to establish a high rate of heat transfer of said first heat exchanger, a manually operable two-position device operatively associated with said engine and selectively operative between a stop position eecting stopping of said engine and a run position effecting continuous running of said engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative between low speed and high speed positions effecting operation of said engine at its respectively corresponding low and high speeds, means for circulating the storage air in said lading compartment into heat transfer relation with said first heat exchanger, means for circulating outside air into heat transfer relation with said second heat exchanger and thence back to the exterior, means for supplying outside air to said engine and for exhausting combustion gases therefrom to the exterior, thermostatic mechanism governed by the temperature of the storage air circulated in said lading compartment and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above said set desired temperature and selectively operative into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary high temperature, means for selectively operating said valve mechanism alternately between its two positions, said lastmentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said valve mechanism between its heating position and its cooling position, and means for selectively operating said throttle control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic ..17 mechanism between its primary, low control condition and its secondary low control condition for correspondingly operating said throttle 'control mechanism between its low speed position and its high speed position and also governedby operation of said thermostatic mechanism between its primary high control condition and its secondary high control'c'ondition for correspondingly operating said throttle control mechanism between its low speed position and its high speed position. l 2. .The railway'refrigerator car combination set forth in claim l, wherein said thermostatic mechanism is selectively settable to establish a'desired temperature of the storage air circulated in said lading compartment in the general range F. tov-F45 F. v l

3, A temperature control system comprising structure containing a medium that is to be selectively heated and cooled, a two-position heat exchange apparatus operatively associatedmwith said medium and selectively operative between heating andcooling positions yeffecting :respectively corresponding heating and cooling of said medium, an internal combustion engine operatively associated` with said apparatus and selectively` operative at lowand highspeeds and arranged so that operation of said engine at` its low speed eiects operation of said ap-` paratus to establish a low rate of heat transfer with respect to said medium and yso that operationof said engine at its high speed effects operation of saidv apparatus to establish a high rate of heat transfer with respect to said medium, a manually operable two-position device operatively associated with said engine Aand selectively .operativebetween a stop `position effecting stopping of said engine anda run position effecting continuous running of said engine, a two-positon throttle control mechanism op,- eratively. associated with said engine and selectively operative between low speed and high speed positions effecting operation of said engine at its respectively corresponding low and high speeds, thermostatic mechanism governed by the temperature of said medium and selectively settablevto establish a desired temperaturethereof, said thermostatic mechanism being selectively operative 'into primary low and primary high control conditions in response jto correspondingrprimary temperatures respectively disposed somewhat below and somewhat above said set desired temperature and selectively operative, into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary high tem-` perature, means forselectively operating said apparatus alternately `between its two positions, saidlast-mentioned means being governed by operation .of said thermostatic mechanism between its primary low `control. condition and its lprimary high control condition for correspondingly operating said apparatus between its heating position and its cooling position, and means for selectively operating said throttle control mechanism alternately b e-v tween its two positions, said last-mentioned means being` governed by operation of said thermostatic mechanism between its primary low controlcondition and its secondary low control conditionfor correspondingly operating-said `throttle control mechanism between its low speed position and its high speed position andvalsogoverned by operation of said thermostatic mechanism between its primary high control condition andI its secondary high control condition for correspondingly operatingj said throttle control mechanism between its low speedrposition and its high speedpcsition.

4. The system setforthf in rclaim, whereinthe low speed of said engine is `substantially the idling speedthereof and the high speed of said engine is substantially-.the normal running speed thereof and is thus substantially greater than the idling speed thereof, whereby the low rate of heat transfer of said apparatus is substantially less than the high rate of heat transfer thereof.

5, The system Set forth inlaial 3.@ wherein thei'hgispower rating of said -engine is relatedto the low speed and high speed loads imposed thereupon said ia'pparaf tus so that each 'ofsaid .imposed loals"is" '1` 1 A tin 'excess of about one-half of the available horsepowe of said en -v gine at the corresponding speed of operaticv thereof,A

6. The system set forth in claim 3, wherein sidthrottle control mechanism is biased into its low speedpo'sition and is'operated against sai-d bias into its high speed' position. 17. The system set forth in claim 3, yv vherein- `sait`l` thermostatic mechanism is also selectively settableto establish the spread of the primary temperature range. 'be tween said primary low control"4 condition 'and said pri-- mary high control condition respectively'belbwandabove said set desired temperature and 1selectivelysettablel tol establish the spread of the secondary temperature range respectively disposed between said primary "lov'v`c :fontrojlA condition and said secondary low control` condition and between said primary highjcontrol condition and said secondary high control condition.

' 8'. A temperature control system comprisingbafheat exchanger arranged in heat-exchange relation with `a medium that is to be selectively heated and cooler 'a refrigerant compressor, a two-position valve mechanism selectively operative between heatingand coolingpositions, said valve mechanism in its heating position"coinpleting a first refrigerantfcircuit includingsaid com-Q pressor and said heat exchanger and Vin which compressed gaseous refrigerant is supplied to said heat exchanger, said' valve mechanism in its cooling posit-ion completing `a sec ond `refrigerant circuit including said compressorl rand said heat exchanger and in which liquid refrigerant is expanded in said heat exchanger, ad'riyejmotor opera# tively associated with said compressor and"` selectively operative yatv low and high speeds, whereby operationof said drive motor at its low speed eiects low speed opera'- tion of said compressor to establish'l'alow rate "ofhet' transfer of said heat exchanger and operationfof said drive motor'at its high speed effects. high speed operation of said compressor to establish v high rate ofheatf'tras fer of said heat exchangenfa manually operable two-p lfition device operatively associated with said driveniotoij and selectively operative between la Istop Yposition effecting stopping of `said drive motor and arun position eie'ctf` ing continuous running of saiddrive motor, a twopositio'n speed control mechanism operatively associated' with ysaid drive motor and selectively operative between low speed and high speed positions effecting operation of said drive motor at its respectively corresponding-low and.,l1 ig h speeds, thermostatic mechanism governedy by the tem# perature of said medium and selectively settable to establish a desired temperaturez thereof, said thermostatic mechanism being selectively operative into primarylow and primary high control conditions in response toco'r responding primary temperatures respectively disposed somewhat below and somewhat above said set desired temperature and selectively operative into secondary low and secondary high control conditions in response to cor-g responding secondary temperaturesrespectively disposed somewhatbelow said primary low temperature and semerf what above said primary high temperature, means for selectively operating said valve mechanism alternately lnetween its two` positions, said last-mentioned means .being governed by operation-ofsaid thermostatic mechanism between its primary low control condition and vits p ri mary hgh control condition for correspondingly :operati ing said valve mechanism betweenits heating; position and its cooling position, and means for-selectively operatfg ing said speed control mechanism alternately between its two positions, said last-mentioned means lbeing governed by operation of said thermostatic mechanismrbetween its primary low control condition andits secondary low control condition for correspondingly operating said speed Ac ontrolrnechanism .between its low speed position and its high ,speed position and also governed b 19 of said thermostatic mechanism between its primary high control condition and its secondary high control condition .for Icorrespondingly operating said speed control mechanism'between its low speed position and its high speed' position.

9.l A temperature control system comprising a heat exchanger arranged in heat-exchange relation with a mediumy that is to lbe selectively heated and cooled, a refrigerant compressor, a two-position valve mechanism selectively operative between heating and cooling positions, said 'valve mechanism in its heating position comple'ting a rstrefrigerant circuit including said compressor and' said heat'exclanger and in which compressed gaseous refrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing a second refrigeranty circuit' including said compressor and said lieaf'exclianger and in which liquid refrigerant is expanded in said heat exchanger, an internal combustion engine operatively associated with said compressor and selectively operative at lowvand high speeds, whereby operation 'f said engine at its low speed effects low speed operation of said compressor to establish a low Yrate of heattransferof said heat exchanger and operation of sa'id engine at 'its' high vspeed effects high speed operation of said compressor to establish a high rate of heat transfer of said heat exchanger, a manually operable two-position device operatively associated with said engine and selectively operative between a stop position effecting stopping of said engine andv a run position effecting continuous running of said engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative between low Ispeed and high speed positions effecting operation of said engine at its Vrespectively corresponding low and high speeds, thermostatic mechanism governed by the temperature of said medium and'. selectively settable to establish a desired temperatnre thereof, said thermostatic mechanism being selectively/operative into'primary low and primary high controlcnditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhatabovesaid set desired temperature and selectively operative into secondary low and secondary high control conditionsoin response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary temperature', for selectively operating said valve mechanism alternately lbetween its two positions, lsaid last-'mentioned means being means governed 'by operation of said thermostatic mechanism between its `low controly 'condition and its primary high control condition for correspondingly operating said valve mechanism between itsy heating position and its cooling position, and means forl selectively operating said throttle control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and lits secondary low control condition' for correspondingly operating said throttle control mechanism ybetweenits low speed position and its high speed position and also governed by operation of said 'thermostatic'mechanism between its primary high controlcondition and its secondary high control condition forl correspondingly operating said throttle control mechbetween its low speed position and its high speed position.

' 10.' The system set forth in claim 9, and further comprisinga device operatively associated with said 'heat exchanger and selectively operative between active and inactive" positions respectively in response to the presence and' inresponse to the absence of a predetermined accumulation of frost upon said heat exchanger, and means responsive to operation of said device into its active positionfor'seizing the control of said valve mechanism frompsaid thermostatie mechanism and responsive to operation of said device into its inactive position for return# ing' the control of 'said valve mechanism to said thermostatic mechanism, saidI device upon seizing control ofl said valve' mechanism enforcing operation' thereof' into. its heating position.

1,1. A temperature' control system comprising a heat exchanger arranged in heat-exchange relation with a medium that is to be selectively heated and cooled, a refrigerant compressor, a two-position valve mechanism selectively operative Ibetween heating and cooling positions, said valve mechanism in its heating position completing a first refrigerant circuit including said compressor and said heat exchanger and in which compressed gaseous refrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing' a secondrefrigerant circuit including said compressor and said heat exchanger and in which liquid refrigerant is expanded4 in said heat exchanger, an internal combustion engine operatively associated with said compressor and selectively operative at low and high speeds, whereby operation of Isaid engine at its low speed effects low speed operation of said compressor to establish a low rate'of heat transfer; of said heat exchanger and operation of said engine at its high speed effects high speed operation of said compressor to establish a high rate of heat transfer Aof said heat exchanger, a manually operable two-position device operatively associated with said engine and selectively operative between a stop position effecting stopping of said engine and a run position effecting continuous running of said engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative between low speed and high speed positions effecting operation of said engine at its respectively corresponding low and high speeds,

V thermostatic mechanism governed :by the temperature of said medium and selectively setta'ble to establish a desired temperature thereof, said thermostatic mechanism lbeing selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above said set desired temperature andselectively operative into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary high temperature, a two-position cyole relay selectively operative between heating and cooling positions, means for selectively operating said cycle relay alternately rbetween its two positions, said last-mentioned means 'being governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating saidcycle relay between its heating position and its cooling position, means governed by operation of said cycle relay between its heating position and its cooling position for correspondingly operating said valve mechanism between its heating position and its cooling position, a two-position speed relay selectively operative between low speed and high speed positions, means for selectively operating said speed relay alternately between its two positions, said last-mentioned means Ibeing Igoverned Iby operation of said thermostatic mechanism between its primary low control condition and its secondary low control condition for correspond- -ingly operating said speed relay between its low speed position and its high speed position and also governed by operation of s'aid thermostatic mechanism between its primary high control lcondition and its secondary high control lcondition for correspondingly operating said speed relaybetween its low speed position and its high speed position, and means governed lby operation of said speed relay |between its low |speed'position and its high speed position for correspondingly operating said throttle control mechanism between its low speed position and its high speed position.

' Y12; A temperature control system comprising a heat l21 exchanger irngedin heat-:exchange relation with a medium that tobe selectively heated and cooled, a .refrigerant compressor, awo-position valve 'mechanism selectively operative between heating and cooling positions, said valve mechanism in its heating position completing a rst refrigerant circuit including said compressor and said heat exchanger and in which compressed gaseous refrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing a second refrigerant circuit including said compressor and said heat exchanger and in which liquid refrigerant is expanded in said heat exchanger, an internal combustion engine operatively associated with said vcompressor and selectively I operative at lowand high speed, whereby operation of said engine at Fits low speed eiects low speed operation of said compressor toestablish a low rate of heat transfer lofsaid heat exchanger and operation of engine at its high speed effects high speed operation oflsaid compressor to establish a high rate of heat transfer of lsaid heat exchanger, a manually operable twoposition device operatively associated with said engine and selectively operative between a stop position effecting Stopping of said engine and a run `position effecting continuous running of said engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative betweenlow speed and high speed positions eiiecting operationjof said engine at` its respectively corresponding low and high speeds, thermostatic mechanism Igoverned by the temperature of said medium and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above 'said set desired temperature and selectivelyy operative into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary high temperature, a two-position electromagnetic cycle relay selectively operative between restored and operated positions respectively operating said valve mechanism into its heatingandcooling positions, means for selectively operating said cycle relay alternately between its two positions, said last-mentioned means being |governed by operation of lsaid thermostatic mechanism between its primary low control condition and its primary high control condition for correspondinglyoperatng said cycle relay between its respective restored and operated positions, a two-position electromagnetic speed relay selectively operative between restored and operated positions respectivelyv operating said throttle control mechanism into its low speed and high speed positions, and means for selectively operating said speed relay alternaitely` between its two positions, said last-mentioned means being governed by operationof said thermostatic mechanism between its primary low control condition and its secondary low conti-oil condition for correspondingly` operating said speed relay between its respective restored and operated positions and also `governed by operation of said thermostatic mechanism" between its primary high control condition and its secondaryhigh control condition 4for correspondingly operating said` speed relay between its respective restored and operated refrigerant circuit including. said compressor.` andV said, heat exchangerand in which liquid refrigerant'is :exi-l panded in saidheat exchanger, an internal combustion? engine Ioperatively associated with said/compresspr'and selectively operative at low and high"speeds,i whereby' control mechanism operatively associated with said engine and selectively operative between low speed and" high,L speed positions effecting operation of said engine at r e' spectively corresponding low and high speeds, prirtnary thermostatic mechanism Igoverned by the tempegratureicifv 'said medium and selectivelysettable to establish4 a deff sired vtemperature thereof, said primary thermostatic= mechanismbeing selectively operative into primary low: and primary lhigh control conditions in response to cor-f' responding. primary temperatures respectively disposed` somewhat below and somewhat above said vset desired temperature, meansffor selectively operating'said valve mechanism alternately 'between its two positions, said ,last'-irientioned means being governed by operation of said primary thermostatic mechanism between itsprimary 10W control conditionrand its` primary high .control con-l dition for correspondingly operating `said v alve mechanism between its heating position and its cooling posi-` tion, secondary thermostatic mechanismA governed'by the temperature of said medium and also selectively 'settable with respect to said set desired'temperature, `said secondary thermostatic mechanism being selectively operative from a prim-ary control condition corresponding tov theprimary temperature range between said primary low temperature and said primary high temperature into secondary lowand secondary high control conditions'in response to corresponding secondary temperatures respectively disposed somewhat below said primary low; teniperature and somewhat abovel said primary high tempera-f ture, and means for selectively operating said throttle control mechanism alternately between its twol positions, said (last-mentioned meansl being governed by operation of said secondary thermostatic mechanism `between its primary'control condition and its secondary low control condition for correspondingly operating said throttle control mechanism between its low speed position and itsV high speed position and also governedby `operation of said secondary thenmostatic mechanism between itsprimary control condition and its secondary high control condition yfor correspondingly operating said throttle control mechanismbetween itslow speedposition and its high speed position. Y I

14. A temperature control system comprising a heat exchanger arranged in heat-exchange `relation with "a medium that is to be selectively heated and cooled, a re-` frigerant compressor, valve mechanism selectively operative between heating and cooling positions, said valve mechanism in its heating position completing a rst refrigerant circuit including said compressor and said heat exchanger and in which compressed gaseousrefrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing a second refrigerant circuit including said compressor and said heat exchanger and in which liquid refrigerant is expanded in said heat exchanger, an electric drive motor connected to saidV compressor and lselectively settable to operate at low and high speeds, whereby operation ofvsaid drive motor at its low speed effects low speed operation of said compressor to, establish a low rate of heat transfer of said heat exchanger and operation of said drive motor at its high speed evie'itf;

high speed operation of said compressor to establish a highrate of heat transfer of said heat exchanger, switching apparatus selectively operative into alow speed position setting said drive motor for operation at its low speed and into a high speed position setting said drive motor for operation at its high speed, an internal combustion engine-selectively operative at low and high speeds, throttle control mechanism operatively associated with said engine and having low speed and high speed positions effecting, operation of said engine at its respectively corresponding low and high speeds, an electric generator connected to said engine, a connector selectively connectible to an outside power line, switching means for selectively connecting saidy drive motor to said generator and to said connector, thermostatic mechanism governed by the temperature of said medium and selectively settable to establish a desired temperature thereof, said lthermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposedsomewhat below and somewhat above said set desired ltemperature and selectively operative into secondary low and secondary high control conditions in response to corresponding secondary temperatures respectively disposed somewhat below said primary low temperature and somewhat above said primary high temperature, means governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said valve mechanism between its heating position and its cooling position, means governed by operation of said thermostatic mechanism between its primary low control condition and its secondary low control conditionfor correspondingly operating said switching apparatus between its low speed position and its high speed position and also governed by operation of said thermostatic mechanism between its primary high control-condition and its secondary high control condition for correspondingly operating said switching apparatus between its low speed position and its high speed position, and additional means controlled by operation of said switching means to connect said drive motor to said generator and governed by operation of said thermostatic mechanismv between its primary low control condition and its secondary low control condition for correspondingly operating said throttle control mechanism between its low speed position and its high speed position and also governed by operation of said thermostatic mechanism between its primary high control condition and its secondary high control condition for correspondingly operating said throttle control mechanism between its low speed position and its high speed position.

l5. The system set forth in claim 14, wherein said electric drive motor is provided with low speed and high speed windings, and said switching apparatus in its low speed and high speed positions respectively selects said low speed winding and said high speed winding to set said drive motor Ito operate respectively at its low and high speeds.

16. A temperatureA control system comprising structure containing a medium that is to be selectively heated and cooled, a two-position heat exchange apparatus operatively associated with said medium andl selectively operative between heating and cooling positions to effect respectively corresponding heating and cooling of said medium, an internal combustion engine operatively associated with said apparatus and selectively operative at low and high speeds and arranged so that operation of said engine at its low speed effects operation of said apparatus to establish a low rate of heat transfer with respect to said medium and so that operation of said engine at its high speed effects operation of said apparatus to establish a high rate of heat transfer with respect to said medium, a manually .operable two-position device operatively associated with saidengin'e and selectively'operaengine and a run position effecting continuous running ofsaid engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative between low speed and high speed positions effecting operation of said engine at its respectively corresponding low and high speeds, thermostatic mechanism governed by the temperature of said medium and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above said set desired temperature and selectively operative into a secondary low control condition in response to a secondary low temperature disposed somewhat below said primary low temperature, means for selectively operating said apparatus alternately between its two positions, said last-mentioned means being governed by operation of saidl thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said apparatus between its heating position and its cooling position, and means for selectively operating said throttle control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and its secondary low control condition for correspondingly operating said throttle control mechanism between its low speed position and its high speed position.

1.7. A temperature control system comprising structure containing a medium that is to be selectively heated and cooled, a two-position heat exchange apparatus operatively associated with said medium and selectively operative between heating and cooling positions to effect respectively corresponding heating and cooling of said medium, an internal combustion engine operatively associated with said apparatus and selectively operative at low and high speeds and arranged so that operation of said engine at its low speed effects operationl of said apparatus to establish a low rate of heat transfer with respect to said medium and so that operation of said engine at its high speed effects operation of said apparatus to establish a high rate of heat transfer with respect to said medium, a manually operable two-position device operatively associated with said engine and selectively operative between a stop position effecting stopping of said engine and a run position effecting continuous running of said engine, a two-position throttle control mechanism operatively associated with said engine and selectively operative between low speed and highspeed positions effecting operation of said engine at its respectively corresponding low and high speeds, thermostatic mechanism governed by the temperature of said medium and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above said set desired temperature and selectively operative into a secondary high control condition in response to a secondary high temperature disposed somewhat above said primary high temperature, means for selectively operating said apparatus alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said apparatus between its heating position and its cooling position, and means for selectively operating said throttle control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic lmechanism between its primary high control condition and' its secondary high control conditionr for correspondingly operating said throttle control mechanism between its low speed position and its high speed position.

18. A temperature control system comprising a heat exchanger arranged in heat exchange relation with a medium that is to be selectively heated and cooled, a refrigerant compressor, a two-position valve mechanism selectively operative between heating and cooling positions, said valve mechanism in its heating position completing a irst refrigerant circuit including said compressor and said heat exchanger and in which compressed gaseous refrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing a second refrigerant circuit including said compressor and said heat exchanger and in which liquid refrigerant is expanded in said heat exchanger, a drive motor operatively associated with said compressor and selectively operative at low and high speeds, whereby operation of said drive motor at its low speed effects low speed operation of said compressor to establish a low rate of heat transfer of said heat exchanger and operation of said drive motor at its high speed elfects high speed operation of said compressor to establish a high rate of heat transfer of said heat exchanger, a manually operable two-position device operatively associated with said drive motor and selectively operative between a stop position effecting stopping of said drive motor and a run position effecting continuous running of said drive motor, a two-position speed control mechanism operatively associated with said drive motor and selectively operative between low speed and high speed positions effecting operation of said drive motor at its respectively corresponding low and high speeds, thermostatic mechanism governed by the temperatnre of said medium and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above set desired temperature and selectively operative into a secondary low control condition in response to a secondary low temperature disposed somewhat below said primary low temperature, means for selectively operating said valve mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said valve mechanism between its heating position and its cooling position, and means for selectively operating said speed control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and i-ts secondary low control condition for correspondingly operating said speed control mechanism between its low speed position and its high speed position.

19. A temperature control system comprising a heat exchanger arranged in heat exchange relation with a medium that is to be selectively heated and cooled, a refrigerant compressor, a two-position valve mechanism selectively operative between heating and cooling positions, said valve mechanism in its heating position completing a first refrigerant circuit including said compressor and said heat exchanger and in which compressed gaseous refrigerant is supplied to said heat exchanger, said valve mechanism in its cooling position completing a second refrigerant circuit including said compressor and said heat exchanger and in which liquid refrigerant is expanded in said heat exchanger, a drive motor operatively associated with said compressor and selectively operative at low and high speeds, whereby operation of said drive motor at its low speed efects low speed operation of said compressor to establish a low rate of heat transfer of said heat exchanger and operation of said drive motor at its high speed elects high speed operation of said compressor to establish a high rate of heat transfer of said heat exchanger, a manually operable two-position device operatively associated with said drive motor and selectively operative between a stop position eecting stopping of said drive motor and a run position effecting continuous running of said drive motor, a two-position speed control mechanism operatively associated with said drive motor and selectively operative between low speed and high speed positions effecting operation of said drive motor at its respectively corresponding low and high speeds, thermostatic mechanism governed by the temperature of `said medium and selectively settable to establish a desired temperature thereof, said thermostatic mechanism being selectively operative into primary low and primary high control conditions in response to corresponding primary temperatures respectively disposed somewhat below and somewhat above set desired temperature and selectively operative into a secondary high control condition in response to a secondary high temperature disposed somewhat above said primary high temperature, means for selectively operating said valve mechanism alternately between its two positions, said lastmentioned means being governed by operation of said thermostatic mechanism between its primary low control condition and its primary high control condition for correspondingly operating said valve mechanism between its heating position and its cooling position, and means for selectively operating said speed control mechanism alternately between its two positions, said last-mentioned means being governed by operation of said thermostatic mechanism between its primary high control condition and its secondary high control condition for correspondingly operating said speed control mechanism between its low speed position and its high speed position.

References Cited in the le of this patent UNITED STATES PATENTS 2,143,687 Crago Ian. 10, 1939 2,221,688 Gibson Nov. l2, 1940 2,257,915 Newton Oct. 7, 1941 2,460,135 Lehane Jan. 25, 1949 2,728,197 Ellenberger Dec. 27, 1955 2,747,376 Mufy May 29, 1956 2,748,572 Parcaro June 5, 1956 2,771,748 Prosek Nov. 27, 1956 2,776,543 Ellenberger June 8, 1957 UNITED STATES PATENT oEETEE CERTFCATE 0F CORRECHN Patent No, 2,887,853 May 9,65 1959 Paul Talmey It is hereby certified Jwhat error appears in 'the printed Specification of the above numbered patent requiring correction and that the Said Le'bera Patent should readas corrected below.

Column l, line 35, for "exchanger said" read mexcnenger and M; column 18, line 23, for ncoolern read cooled w; column 19, line 6F after "temperature, inseriJ means u; line 48, strike oni'J "me-ene, second occurrence; column 2l, line 14, for speed reed w speeds nl Signed and sealed this 3rd day of November l950 SEAL) ttest:

KARL H, AXLINE RBEB'I (l. WTSN Atteeting Oicer Commissioner of Patens