US2203406A

US2203406A - Air conditioning apparatus

Info

Publication number: US2203406A
Application number: US645552A
Authority: US
Inventors: Jr Arthur E Dempsey
Original assignee: North American Car Corp
Current assignee: North American Car Corp
Priority date: 1932-12-03
Filing date: 1932-12-03
Publication date: 1940-06-04
Anticipated expiration: 1957-06-04

Description

' June 4, 1940. A. E. DEMPSEY. JR 2,203,406

AIR CONDITIONING APPARATUS Filed Dec. 3, 1952 5 Sheets-Sheet 1 x MO1771- g9 June 4, 1940. A. E. DEMPSEY. JR

AIR CONDITIONING APPARATUS Filed Dec. 3, 1932 3 Sheets-Sheet 2 g- 4135 f I 37 I am 55%? Q r 6 e r. @ox x Mm; J a? Patented June 4, 1940 UNITED STATES PATENT OFFICE AIR CONDITIONING APPARATUS tion of Illinois Application December 3, 1932, Serial No. 645,552

19 Claims.

My invention relates in general to air conditioning and has more particular reference to temperature control of the atmosphere in compartments and more specifically to compartments l3 including refrigeration means for maintaining a storage compartment below a predetermined maximum when the outer atmosphere is relatively warm, and alternately operable heating means for maintaining the temperature within the com- 20 partment above a predetermined minimum when the external atmosphere is relatively cold;

To provide refrigerating means operable while the car is in transit and having associated means to store up refrigerating energy in excess of that 93 required to maintain the atmosphere in the car below a predetermined maximum temperature while the car is in motion and the apparatus is functioning, and to liberate the stored refrigerating energy when the refrigerating means be- 20 comes inoperative while the car is stationary;

To provide a refrigeration system including cooling devices adapted for selective operation, the one for cooling the atmosphere of the car and the other for storing refrigerating energy for lib- :zr, eration after the temperature of the car has reached a predetermined value;

To provide a refrigerating apparatus adapted to maintain the atmosphere in the car below a predetermined temperature and cooperatively associated heating means operable to maintain the atmosphere in the car above a predetermined minimum temperature;

To provide a refrigerating device to maintain the temperature of the car below a predeter- 45 mined value, including means operable to store refrigerating energy in excess of that required to maintain the predetermined temperature and to liberate the stored energy when the refrigerating apparatus becomes inactive in order to continue 50 the refrigerating effect for an appreciable interval, and heating means operable when a predetermined minimum temperature is reached to prevent further cooling below said minimum temperature;

55 To drive the compressor continuously in one direction by the movement of the car while in transit in either direction;

To operate the system by electromotive means powered either by direct current from a direct current source actuated by the movement of the 5 car or by alternating current when the car is stationary, in which case the electromotive means is adapted to deliver direct current for operating and for controlling the system;

To utilize a direct current power source actuated by the movement of the car for operating the system while the car is in motion and to utilize alternating current for operating the system when the car is stationary;

To provide heating and cooling apparatus for cars, wherein the apparatus is operated and controlled from the moving parts of the car by means of an electrical connection;

To operate the refrigerator system by means of a direct current electrical motor powered from a direct current generator driven from the axle of the car when the car is in transit and to operate the system by means of power developed by the motor operating as a generator driven by alternating current power when the car is stationary;

To provide a temperature control for refrigerator cars including heating means and cooling means powered from the movable portions of the car in order to maintain the atmosphere of the car between predetermined adjustable maximum and minimum temperatures;

To provide a cold storage device, whereby the refrigerating energy developed in excess of that required to maintain the atmosphere of the car below a predetermined temperature may be 35 stored up for future use after the refrigerating system becomes inactive;

To utilize a non-liquid, cold storage, or holdover material in order to eliminate the disadvantages of corrosive liquid storage materials;

To provide a cold storage device, including cooling coils embedded in a suitable, lightweight, solid, cold storage material having high specific heat whereby to store potential refrigerating energy in condition for liberation as and when required;

To provide control devices for selectively actuating the heating and cooling devices in accordance with the temperature prevailing within the refrigerating compartment in order to maintain the atmosphere below a predetermined maximum temperature and to automatically apply heat when necessary in order to maintain the atmosphere above a predetermined minimum temperature;

To provide a refrigeration system actuated from the axle of a car, including means to store a temperature control system may be powered from an external source when the car remains stationary for a length of time in excess of the interval provided for by the cold storage element of the system;

To provide means for selectively powering both the heating and cooling systems from the axledriven generator when the car is in transit and from an external source of electrical power when the car is stationary;

To provide for the operation of the heating and refrigerating system by means of unidirectional current while the car is in transit in order to maintain a substantially constant refrigerating effect at all speeds, and for the operation of the system by means of alternating current from a commercial power line when the car is stationary;

To provide for powering the heating and refrigerating system from the axle of the car while in transit, or from an electric motor connected to an external power source when the car is stationary; to provide an electric generator driven from the axle of the car to supply power for operating a heating element for maintaining the temperature of the car above a predetermined minimum in conjunction with means operating from the axle of the car for maintaining the temperature of the car below a predetermined maximumgand means driven from the axle for circulating air in the car in order to promote the operating efficiency of the heating and cooling means; to provide refrigerating apparatus for the car having a coil operable to directly refrigerate the atmosphere in the car and an alternately operable coil to deliver refrigerating energy in excess of that required to maintain the temperature within the car below a predetermined value to a cold storage device for liberation to maintain the predetermined low temperature 'for an appreciable period after the refrigerating system becomes inoperative; to provide a temperature control system including an axle-driven refrigerator, an axle-driven heating device, and thermostatic means for selectively controlling the heating and refrigerating devices, said control means being operated by power supplied from the axle of the car no matter in which direction the car may travel; and to provide switching means for operating the heating, cooling, and air-circulating apparatus selectively from an axle-driven, direct-current generator, or from an external source of alternating current power, said switching means including the arrangement of the heating and air circulating elements whereby the same may be operated at full heat or at fractional heating capacity.

Numerous other objects and advantages of the invention will be apparent from the following description, which, taken in connection with the accompanying drawings, discloses a preferred embodiment of the invention.

Referring to the drawings:

Figure 1 is a sectional view taken longitudinally through a railroad refrigerator car to illustrate a preferred embodiment of my invention;

Figure 2 is a sectional view taken substantially along the line 2-2 in Figure 1;

Figure 3 is a diagrammatic representation of the electric connections employed for operating and controlling the temperature regulating sys tem illustrated in Figures 1 and 2;

Figures 4 and 5 illustrate modified arrangements embodying the invention; and

Figure 6 is a perspective view of a modified form of the cold storage device.

To illustrate my invention, I have shown on the drawings, a preferably ins lated casing II comprising any type of compar ment l2 having temperature control apparatus built in accordance with the teachings of my present invention.

The casing M, in the illustrated embodiment, preferably comprises the body of a railroad refrigerator car and is mounted on wheels I3. The

temperature control apparatus preferably includes a system for the circulation of any suitable refrigerating medium, such as ammonia,

sulphur dioxide, ethyl chloride, or any other suitable medium; the system includes a compressor 85, a condenser ll, cooling coils l9 and cold storage devices 25 located in any suitable or convenient position on or in the casing, there being preferably a coil i9 and a cold storage device 28 behind partitions or bulkheads M at each of the opposite ends of the casing it although of course, the coils l9 and the devices 2| may be located on the side walls or roof of the compartment, or in any other suitable position in the compartment, if desired. The bulkheads preferably have openings l6 and M? respectively near the floor and near the ceiling of the compartment to facilitate the circulation of air between the compartment and the cooling devices l9 and 2E. The system also includes suitable piping or conduits 23 for connecting the compressor, condenser and cooling devices I9 and 2| in a circulating system.

The coils l9 and the devices 28 at the opposite ends of the compartment are arranged for parallel operation and a temperature regulated control valve 25 is provided to direct the fiow of the refrigerating medium either to the refrigerating coils 89, or to the cold storage devices 26.

The refrigerating medium is circulated in the system from the compressor l5 through a pressure-limit switch 2W, an oil interceptor 29, and the coils M of the condenser, thence through an expansion valve 24 and the control valve 25, thence either through the parallel circuits 33, including the coils H! at opposite ends of the storage compartment, or through the parallel circuits 35.through the cold storage devices 2| at opposite ends of the compartment and finally back through the return conduit 37! to the inlet of the compressor 85.

The temperature control apparatus includes blowers 38 for circulating the air in the car, said blowers, as shown in Figure 1 of the drawings, being preferably located at opposite ends of the car with their intakes near the ceiling of the compartment l2, and arranged to direct currents of air downwardly through the conduits 39, the discharge ends of which are located adjacent the floor of the car and are provided with heating elements 40. The control apparatus also includes thermostatically operated devices preferably located within the car in any suitable or convenient position. These devices, as shown in Figure 1 of the drawings, are carried by a suitable support 43 mounted on the ceiling of the compartment.

ing elements 4|, and the compressor I5. This control apparatus preferably comprises electrical circuits and circuit-switching means conveniently located in a control cabinet preferably located on the underside of the car bottom.

Means is also provided for powering the refrigerating system, the blowers, and the heating elements from one of the car axles or alternatively from an external source of power. The compressor l5, which may be of any preferred form and type, is preferably supported on a suitable frame 41 mounted beneath the central portions of the car, the frame being of open construction in order to permit air to circulate around the compressor in order to cool the same. The compressor is drivingly connected with a direct current motor 49, which, in turn, is provided with suitable electrical connections for deriving operating power from a constant potential, variablespeed, direct current generator 5| which delivers direct current without change in polarity no matter in which direction the car travels. The direct current motor is carried in the frame 41 with the compressor, and the generator is located in any suitable or convenient position beneath the car body and is drivingly connected as by means of the belt or chain 53 with a car axle 55. The driving element 53 operates over suitable pulleys or sprockets 51 and 59 mounted respectively on the car axle and on the shaft of the generator. The driving elements 53, 51, and 59 are so arranged that the pulley 51 may swing out of alignment with the pulley 59 when the car is traveling a curved path without interfering with the driving connection. Of course, any suitable equivalent driving device may be employed, such as an extensible shaft provided with universal joints and operatively geared at its opposite ends to suitable gears on the axle and on the generator. Or the generator may be mounted directly on the truck or bogie, which carries the axle 55, and may be either drivingly connected with the axle by mechanical means, or may be built onto the axle itself, in which case the generator swings with the axle and no provision need be made for the relative displacement of the axle with respect to the generator while the car is traveling a curved path. In any event, the movement of the car, in transit, through its axle drives the generator 5| and when the car is moving at higher than a predetermined minimum speed, the generator produces current at constant potential and unchanging polarity, no matter how fast nor in which direction the car may travel. The current produced by the generator is used for driving the motor 49 and for other purposes which will hereinafter be more fully explained.

Means is also provided for driving the compressor from an external power source when the car is stationary. For this purpose, I prefer to utilize an alternating current motor 6|, although other forms of motive devices may, of course, be employed if desired. The compressor, the directcurrent motor 49, and the alternating-current motor El preferably have their shafts directly coupled together as shown at 63, although, of course, if the compressor employed is other than the rotary type shown in the drawings, a direct coupling between the compressor and the motors 49 and 6| cannot be accomplished, but, in such a case, I prefer to employ a geared, belted, or

cranked connection for driving the compressor.

Thus a suitable connection is provided whereby the alternating current motor may be electrically connected in a readily detachable manner with a source of external power in order to drive the compressor and thus operate the refrigerating system and drive the direct-current motor as a direct-current generator when the car is stationary.

.If desired, the motor 49 and the motor 6| may be built as a unit as by providing an ordinary repulsion induction motor with a commutator and brushes to connect the rotor for direct current operation. Such a device can be driven as a direct-current motor by connecting its brushes with a suitable source of direct-current, as, for instance, the generator 5|, or can be driven as an alternating current motor-direct current generator by connecting the induction motor leads to a suitable alternating-current source. However the eifect is accomplished, the motor-generator set 49, 6| provides for operating the system either by direct current produced by the motion of the car while in transit or by alternatingcurrent when the car is stationary. In either event, the operation of the system is controlled, at least, in part by direct current of constant or unchanging polarity produced by the generator 5| while the car is in motion in either direction, or by the motor generator combination 49, 6| when the car is stationary.

An important advantage of my present invention is that the compressor is always driven in the same direction whether the car is stationary or in motion and regardless of the direction of car travel.

The condenser I1 is preferably mounted on the outside of the car body in position exposed to the external air currents created by movement of the car in either direction in order to promote the dispatch of heat therefrom. However, the condenser may be located in any convenient position on the underside of the car body, the condenser being of compact construction so that it may be mounted adjacent the compressor. The condenser comprises one or more coils of pipe 65 provided with extended heat-radiating fins or other heat-transferring surfaces and is mounted within a suitable housing 61 through which a circulation of air may be maintained by means of the fan 69 in order to efficiently and rapidly cool the refrigerating medium compressed in the compressor and delivered thereby through the pressure limit switch 21 and the oil interceptor 29 to the condenser. The fan 69 is preferably electrically driven and suitable connections are provided for supplying the same with power from the generator 5| while the car is moving or from the motor 49 driven as a generator by the motor 6| when the system is being actuated from an external source of power. The oil interceptor 25 is positioned in the conduit connecting the compressor discharge with the condenser inlet. The pressure limit switch 21 is also located in this conduit 1| between the compressor and the condenser. The oil interceptor 29 may be of any suitable or preferred form for the purpose of removing oil carried in suspension by the compressed refrigerating medium forced from the compressor and thus eliminate trouble in the condenser and other portions of the circulating system caused by the oil tracings in the circulating medium. A supply pipe 13 for the compressed and cooled refrigerating medium delivered from the condenser leads into the refrigerator compartment and connects with an expansion valve 24 and thence to the valve 25 controlling the distribution of the refrigerant through the parallel circuits 33 to the coils I9, or through the parallel circuits 35 to the coils of the cold storage devices H. The valve 25 may be of any suitable or preferred form for directing the refrigerant selectively into the circuits 33 or into the circuits 35. When the refrigerant is directed through the circuits 83, the atmosphere in the car will be refrigerated by direct contact with the coils 19. When the atmosphere has thus been cooled below predetermined temperature, the thermostat devices on the mounting 43 operate through the control circuits hereinafter more completely described, to cause the valve 25 to direct the refrigerant into the circuit 35. At this time the refrigerating energy in excess of that required to cool the car down to the temperature at which the switching occurs, will be stored up in the cold storage devices H for future liberation whereby to maintain the atmosphere in the car in a substantially cold condition for a considerable interval after the refrigerating apparatus becomes inactive, as when the car is stationary for a period long enough to demand that the apparatus be connected for operation to an external power source.

The cold storage devices M, as illustrated in Figure 1 of the drawings, comprise tanks 75 containing a fluid cold storage or hold-over medium, preferably brine, that is to say, a solution of salt or calcium in water and suitable conduits or coils of pipe 59 immersed in the brine and connected with the refrigerating system. Alternatively as shown in Fig. 6, I propose to provide cold storage devices 22 consisting of coils 88 of suitable configuration embedded in a block it of relatively solid or moldable material having a high specific heat factor. Material, such as rubber or rubber compounds, form suitable moldable material in which to embed the coils. In operation, the refrigerating medium flows through the coils of the cold storage unit and the cold storage medium is cooled thereby, that is to say, absorbs refrigerating energy. The amount of energy absorbable in the cold storage or hold-over unit depending upon the specific heat of the material employed. Cold storage units made by embedding the coils in a moldable compound, such as rubber, have a distinct advantage in that there is no corrosive fluid involved as in the case of a brine tank cold storage unit. Leakage and consequent damage to surrounding parts and apparatus is thus avoided.

The cold storage or hold-over devices 2i particularly if of the alternative solid construction 22 need not necessarily be placed in the ends of the car behind the partitions i l but may be conveniently located in any suitable or convenient position as on the side walls or roof of the compartment l2.

In Figure 3 of the drawings, I have illustrated a schematic diagram of electrical connections whereby the several elements of the heating and cooling system are operatively connected together and the operation thereof correlated in order to automatically maintain the car in substantially cold condition between adjustable limits of maximum and minimum temperatures.

In the apparatus illustrated, the constant current, variable speed, direct-current generator 50 has a field coil 52 and is driven from the axle 55. The generator is of any suitable or preferred construction adapted to deliver direct current at constant potential and polarity from the brush terminals 8i no matter which direction the generator arm is turned by the car axle. The brush terminals are connected with conductors 88 and 84 forming direct current buses, there being a solenoid switch 85 normally biased by means of the spring 86 to open position, in series in the direct current bus 83 adjacent the generator 5|. The solenoid switch 85 has an operating 001189 of the potential type, connected to the bus conductor 83 between the switch 85 and the generator terminals and to the conductors 84 in order to close the switch against the bias of the spring means 86 as soon as the generator has reached a minimum operating speed to deliver its normal potential between the terminals 89. The solenoid switch 85 also has a holding coil 9| in series in the bus conductor 83 in which the switch 85 is connected so that the switch 85 will be held closed as long as current is flowing in the conductor 83. The bus conductor 88 also has a second solenoid switch 98 normally biased toward open position by the spring means 95, said solenoid switch 88 having an operating coil 9'! of the potential type, one end of which is connected with the bus conductor 88 between the switches 85 and 98 and the other end of which is connected to one contact of a switch 99, the other contact of said switch being connected through the conductor nm to the direct current bus 84 thus completing the operating circuit of the switch 93 so that the switch will be closed against the bias of its spring whenever switches 85 and 99 are closed with power on the

bus conductors

83 and 84.

The direct current motor 48 has a field coil 50 which is connected between the

buses

83 and 84 in such a fashion that the

switches

85 and 93 control the flow of direct current along the buses between the motor 39 and generator 5|.

The direct current motor 48 is provided with a starting compensator, comprising a solenoid switch 583 inserted in one of the bus-conductors between one end of the coil 58 and a brush terminal m5 of the motor. The switch is normally biased by means of the spring ml toward open position and a starting resistance M9 is connected in parallel with the switch'opening. The switch H83 has an operating coil M l of the potential type connected in the bus conductor 84 between the switch 683 and the motor terminals. The switch 988 is closed when the back electromotive force, created by the motor in starting, has reached a predetermined value in order that, upon starting, the resistance will be in series with the armature of the motor. When the motor has reached a speed to deliver a counter electromotive force sufficient to close the switch I03 against the bias of its spring, the resistance I88 is short circuited through the switch and the full potential is delivered by the generator to the armature of the motor.

The condenser cooling-fan-motor 69 is connected with the direct current bus 88 between the motor 49 and the switch 83 by means of the conductor M14 and is connected with the direct current bus 84 as by means of the conductor so that the condenser cooling-fan-motor will operate either when the car is moving with the generator 501 in operation (the

switches

85 and 93 being closed) or when the car is stationary and the motor M is driving the motor 49 as a generator.

As heretofore described, the alternating current motor 60, and the motor 49 are preferably coupled together and both are operatively connected for driving the compressor l so that either the direct current motor 49 or the alternating current motor 65 may be utilized to drive the compressor.

When the motor 48 is driving the compressor,

the motor 6| is being driven in a substantially idle condition. When the motor BI is employed to drive the compressor, it will also drive the armature of the motor 49, which, being of the direct current type, will operate as a direct current generator. In other words, when the car is stationary and the motor 5| is being driven from a source of external power, the driven motor 49, operated as a direct current generator, will supply direct current to the bus bars 84, for a purpose which will hereinafter be more fully described.

The motor BI is preferably of the squirrel cage type having a rotor I2I and stationary windings I23 of any suitable form for causing the rotor to turn when alternating current is applied to the windings.

As illustrated in Figure 3 of the drawings, the windings I23 form a three-phase delta connection to which three-phase alternating current is supplied by means of the conductors I25, which are connected between the windings I23 and the poles I21 of a selector switch I29. The switch illustrated is of the triple-pole, double-throw type having switch blades pivoted to the central blade supports I31 in position to swing selectively into engagement with the blade-receiving terminals I21 or into engagement with the blade-receiving terminals I33.

The blade-carrying terminals I3I are connected to the conductors I35, which terminate in a suitable outlet I31 by which a detachable electrical connection may be made between the conductors I35 and an external source of alternating current power whereby when the switch blades are positioned in contact with the blade-recelving terminals I21, alternating current power may be fed through the conductors I35 and I25 to the motor BI.

The outlet of the compressor is connected with the pressure-limiting switch 21. This switch is normally open but is adapted to close when the pressure in the discharge line of the compressor exceeds a predetermined value. The normally open switch is in a circuit I I3 extending from the bus connector 84 to the bus connector 83 between the switch 85 and a terminal 8| of the generator and includes the operating coil II5 of a solenoid switch I I1, which is in series in the operating circuit oi the coil 89 which operates the switch 85. The switch H1 is normally biased toward closed. position as by the spring H9 so that as long as the pressure in the discharge line of the compressor does not exceed the predetermined maximum, the switch 21 will be open and the switch H1 will be closed so that the coil 89 may hold the switch 85 in closed position so long as the generator 5| is in operation. If, for any reason, the pressure in the discharge line becomes dangerously high, the switch 21 will close, causing the coil II 5 to open the switch II1 against the urge of its spring, thus rendering the coil 89 inoperative and permitting the switch 85 to open. This will prevent electrical power from being de- 3 livered from the generator to the motor which will cause the same to slow up and relieve the excessive pressure in the discharge line of the compressor.

If desired, the pressure-limiting switch 21 may also be provided with means for controlling the operation of the motor 5| in order to provide a similar protection against excessive pressures in the discharge line of the compressor when the same is being driven by the motor Bl.

Two of the blade-receiving contacts I33 are connected by means of suitable conductors I39 to the heaters 4 I, which are preferably connected in series between the conductors 39. The blowers 38 are operated by electric motors I4I, which also are preferably connected in series between the spaced conductors I39 so that when the blades of the switch I29 are in engagement with the blade-receiving conduits I33, one phase of the alternating current power supplied from the external power source through the outlet I31 will be applied for driving the motors MI and for operating the heaters 4I.

Means is provided for short-circuiting the conductors I39 whenever the heaters are powered from the direct current busses. This occurs only when the car is in motion and the connection by which power is supplied to the system from an external source is broken. This is to permit the blower motors and heaters to be operated in parallel by direct current produced by the generator 5| when the car is in motion, and comprises a switch I45 connected for short-circuiting the conductors I43 when in closed position. The switch I45 is normally urged toward open position by means of the spring I41 and has an operating coil I49 connected to the conductor 83 between the

switches

85 and 93, and to the conductor 84, so that whenever power is applied to these bus conductors, as when the heaters are powered therefrom, the coil I49 will close the switch I45 against the bias of its spring and will hold the switch closed while the heaters are in operation.

The conductor I5I which joins the heaters, and the conductor I53 which joins the motors, are connected to the bus conductor 84 as by means of a conductor I43 with the common con ductor Illl which in turn is connected with the direct current bus conductor 84. One of the conductors I39 also is connected by means of the conductor I51 through a control switch I59 and the conductor IE! to the direct current bus conductor 83 between the

switches

85 and 93 so that the heater 4| and the blower motors I4I may be powered from the direct

current buses

83 and 84 when the car is in transmit and the system being operated by power delivered from the generator 5|, it being understood that under such conditions the switches 85, I45 and I59 will be closed thus throwing the heaters 4| and motors 14! in parallel between the

bus conductors

83 and 84 carrying the potential developed by the generator 5|.

The switch I 59 is normally biased toward open position by means of the spring I60 and has an operating coil I52 for closing the switch against the bias of its spring. The operating coil is connected by means of the conductor I6I to the direct current bus 83 between the

switches

85 and 93 and is also connected through a control switch I64 and the return conductor IDI to the direct current bus 84.

The reason for operating the heaters and blowers in parallel from the direct current system and in series from the alternating current system is that the most efficient apparatus for use in the direct current system has a voltage characteristic substantially less than the voltage available in ordinary commercial power lines carrying alternating current so that it is preferable to design the direct current apparatus having a voltage such that the heaters and motors can be operated in parallel with the full direct current voltage across each heater and blower element and can be operated in series when connected in the alternating current system.

If desired, however, the connections may be made to permit operation of the heaters and blowers in series when connected to the direct current system simply by omitting the switch I46 and its connections and by omitting the conductor I43 while connecting the conductor ifll to the conductor I39 other than the one with which the conductor H51 is connected. Suitable connections also may be provided for operating the alternating current system from commercial power lines having different alternating current voltages.

The temperature regulating control valve 29 is normally biased, preferably by gravity, to

direct the refrigerating medium into the parallel circuits 33, which include the direct cooling coils I9. The valve has a coil 199 for shifting the valve against its bias to condition it to deliver the refrigerating medium into the parallel circuits 35. The coil H63 is connected through a switch I65 and the return conductor H to the direct current bus conductor 99 and is also connected by means of the conductor [I99 to the direct current bus conductor 99 between the motor 49 and the switch 99 so that when the switch I65 is closed, the coil I163 may be actuated from the direct current system either when the generator M is supplying current to the system or when the motor 49 is driven as a generator Si by the motor and is'supplying the current to the system but cannot be operated when the switch 93 is open with the power being supplied by the generator M. It will be noted also that the operating coils 91 of the switch 99 and H62 of the switch 59 can be actuated only when the generator M is supplying power to the direct current system and cannot be operated when the motor 49 is operating as a generator to supply power to the system.

The operation of the system is controlled from thermostatic means mounted on the support 43, the devices to be controlled including the magnetic valve 25, the heating elements and fans MI and the switches and H59.

It will be noted that these devices are thermostatically controlled in the illustrated embodiment only when the direct current system is in operation, that is to say, when the car is in transit. It is ordinarily unnecessary to control the heating and cooling devices when the car is stationary for the reason that it is unnecessary to limit the cooling effect applied to the car while it is waiting to receive a load of freight. Even if the car is cooled substantially below the temperature at which the freight is to be maintained, the precooled car will become heated to a certain extent during the loading operation, for which reason, it is unnecessary to limit the pre-cooling except, insofar as there is a natural limit of temperature to which the car may be pre-cooled, which natural limit will depend upon the natural limit of the cooling apparatus and the temperature at which the pre-cooling is accomplished. Neither is it necessary to control the pre-heating of the car for similar reasons. I, therefore, do not show any means for controlling the extent of the preheating or pre-cooling which may be accomplished when the system is operated from an external power source when the car is stationary. However, it is obvious that the devices, which control the operation of the system in response to temperature changes in the car, may be arranged to operate when the system is operated from an external power source when the car is stationary.

The temperature control is effected from the thermostatic means which is carried on the support 43 through switching devices controlled by the thermostatic means. The switching devices in turn control the operation of the switch 93. This latter switch in turn controls the operation of the refrigerating system.v The switching devices also control the switch I59, which controls the operation of the heating devices. The switching devices also control the valve 25, which controls the delivery of the refrigerating medium either to the direct cooling coils l9, or to the cold storage devices 20.

It is desired that the switch 93 be closed in order to maintain the refrigerating system in operation, that is to say, in order to drive the condenser, cooling-fan-motor 69 and the motor 99 when the valve 25 is gravity-actuated so as to deliver the refrigerating medium to the coils I9, as long as the temperature within the car exceeds a predetermined temperature, for example about 34 Fahrenheit. It is further desired to actuate the valve 26 in order to deliver the cooling medium to the cold storage devices 2! at a predetermined temperature, about 3 2 Fahrenheit, in order to store up the cooling energy, in excess of that required to maintain the temperature below 32 Fahrenheit. By doing this, the stored energy may later be used in maintaining the temperature of the car below 34 Fahrenheit for an appreciable period while the car is standing idle and before the cooling system is operated from the external power source. It is further desired to cause the switch 93 to open, thus rendering the cooling system inactive, when the temperature within the car reaches about 30 Fahrenheit; and it is desired further to place the heaters M and blowers MI in operation by closing the switch 059 when the temperature within the car reaches about 28 Fahrenheit. After the heating apparatus has been in operation long enough to raise the temperature in the car to about 29 Fahrenheit, it is desired to open the switch I59 in order to render the heating apparatus inactive. If the temperature within the car continues to rise, it is desired to again close the switch 93 when a temperature of about 31 Fahrenheit is reached; and to switch the valve 25, when a temperature of about 34 Fahrenheit is reached. in order to again deliver the refrigerating medium to the direct cooling coils l9. The switches 93 and I59 and the operating coil I63 may, of course, be controlled to operate at other than the temperatures specified but the foregoing temperature range is mentioned merely to indicate the sequence of operation of the various devices.

- In order to accomplish this desired sequence of operation, a plurality of control switches are employed. In the illustrated embodiment, these control switches are arranged in groups, the several groups I66, I61, and I68 preferably being mounted on separate panels and each group including one of the control switches 99, I64, and I65. Each group also includes switches I69, I16, and HI adapted to open and close with the corresponding control switch of its group. Switch I69 opens and closes with switch I65. Switch I10 opens and closes with switch 99, and switch "I opens and closes with switch I64. Each group also has a switch I12, I13, and I14, which is adapted to open when the corresponding control switch of the group is closed. Switch I13 is open when the switch 99 is closed, and switch I14 is open when switch I64 is closed. The shiftable elements of within the car is 32 Fahrenheit and to engage the switches of each group are carried on members I15 by means of which the switches may be moved to open and closed position. Each group of switches has associated with it a pair of operating coils; group I66 having operating coils I11 and I19; group I61 having operating coils I8I and I83; and group I68 having operating coils I and I81. The coils I11, I8I, and I85 are adapted to move their corresponding members I15 upwardly to close the operating switches 99, I64, and I65, and the operating coils I19, I83, and I81 are adapted, when actuated to move the members I 15 downwardly, to open the switches 99, I64, and I65. The coils I11, I19, and I8I; I83, I85, and I81 are connected through the return connector IN to the direct-current bus conductor 84 while the coil I11 is connected through the switch I12 to a contact I89 of a thermostat device carried by the panel 43. The blade I9I is connected by means of the conductor I04 to the direct-current bus 83 between the switch 93 and the motor 49. This enables the coils I11 and I19 to be energized either when the car is in transit or when it is stationary. When the car is in transit, the direct-current generator 5| delivers power to the

buses

83 and 84. When the switch 93 is closed, the power delivered by the generator may be applied to the circuits which includes the coils I11 and I19. When the switch 93 is open, however, the power developed by the generator cannot be applied to the circuits including these coils. This, however, is not a disadvantage because the refrigeration system, when operated from the generator 5|, is out of commission when the switch 93 is open and does not require temperature control of the switch 25. When the car is stationary and the alternating current motor 6| is driving the motor 49 as a direct-current generator, power will be delivered by the direct-current motor, operating as a generator, to the

buses

83 and 84 and this power is always available to energize the circuits including the coils I11 and I19 whether or not the switch 93 is closed. In this way, the switch 25 is thermostatically controlled whenever the refrigeration system is in operation. The blade I9I is adapted to operate between the contact I89 and a second contact I93, which is connected by the switch I69 to the operating coil I19. The coils I8I and I83 are connected respectively through the switches I13 and I10 to the spaced contacts I and I91 of a second thermostat unit carried on the panel 43, and theblade I99 of which unit is connected by means of the return conductor I6I to the direct-current bus conductor 83 between the

switches

85 and 93 so that the coils I8I and I83 may be selectively controlled to operate the switches of group I61 only when the car is in transit, i. e., when the generator 5| delivers power to the direct-current system and not when the motor 49 is delivering power to the system during which period the switch 93 is also open. The coils I85 and I89 are connected respectively] through the switches I14 and HI to the stationary contacts 20I and 203 of a third thermostat carried by the panel 43, the blade 205 of which thermostat is connected through the conductor I6l to the direct-current bus 83 so that the

coils

85 and 81 may be powered from the direct-current system only when the car is in transit.

Operation In operation, the blade I9I is arranged to engage the contact I89 when the temperature the contact I93 when the temperature within the car is 34 Fahrenheit. The blade I99 is arranged to engage the contact I95 when the temperature with the car is 31 Fahrenheit and to engage the contact I91 when the temperature is 30 Fahrenheit; and the blade 205 is arranged to engage the contact 203 when the temperature is 29 Fahrenheit and to engage the contact 20I when the temperature is 28 Fahrenheit.

When the temperature within the storage compartment is 34, the switch I65 has been opened under the influence of the coil I19; the switches I69 and I12 are respectively open and closed and the coil I63 of the valve 25 is deenergized. In this condition, the valve is gravity-actuated to deliver the refrigerating medium into the circuit 33 leading to the direct cooling coils I9. If the temperature within the car falls below 34, the blade I9I releases the contact I93 but does not efieet the condition of the switches in group I66 until the blade engages the contact I89 which occurs when the temperature within the car is 32. At this time, the coil I11 is energized through the switch I12 and causes the switch I65 being respectively closed and opened by this energization of the coil I8I.

If the temperature in the storage compartment falls below 31, the blade I99 releases the contact I95 but this does not affect the condition of the switches of group I61 until the blade engages the contact I91 when the car temperature is 30. At this instant, a circuit is completed through the switch I10 to energize the coil I83 and thus open the switch 99, which, in turn, deenergizes the coil 91. This permits the switch 93 to open under the influence of the spring 95 in order to disconnect the

motors

49 and 69 from the generator. Since these motors drive the compressor and the condenser cooling fan, the opening of switch 93 renders the refrigerating system inactive. When the temperature within the storage compartment reaches 29, the switch I64 is opened under the influence of the coil I81, the switches HI and I14 being respectively open and closed. If the temperature in the storage compartment falls below 29, the blade 205 releases the contact 203 but this does not affect the condition of the switches of group I68 until the blade engages the contact 20I, which occurs when the temperature within the car is 28 Fahrenheit. When the blade 205 engages the contact 20I, a circuit is completed through the switch I14 to energize the coil I85 and thus to close the switch I64. When the switch I64 closes, the operating coil I62 is energized and causes the switch I59 to close against the tension of the spring I60. This completes a circuit through the conductor I51 in order to operate the heaters M and blowers I4I from the

directcurrent buses

83 and 84.

When the temperature within the storage c0mpartment is equal to or less than 28 Fahrenheit, the switch I64 is closed, switches Ill and I14 being respectively closed and open. If the temperature within the storage compartment rises above 28 Fahrenheit, the blade 205 releases the contact Elli but this does not affect the condition of the switches of group 0% until the blade reaches the contact 293. When this occurs, a circuit is completed through the switch ill to energize the coil i871 thus opening the switch I 64 and breaking the circuit energizing the operating coil Hi2. This permits the switch it to open under the influence of the spring Wild and breaks the circuit by which the heaters and blowers are energized. As the temperature continues to rise, at 36, the switch 99 is open under the influence of the coil Hit. If the temperature rises above 30, the blade 11% releases the con tact ill! but this does not affect the condition of the switches in group it? until the blade en gages the contact W5. When this occurs, a circult is completed through the switch M3 to energize the coil Hit in order to close the switch 99. This completes a circuit through the operating coil ill which closes the switch Q3 against the tension of the spring 95 thus permitting power to be delivered from the generator M to the compressor-driving-motor l9 and to the condenser-cooling-motor lid and places the refrigerating system again in operation. When this occurs, the refrigerating energy is delivered to the cold storagedevices iii.

If the temperature continues to rise, at 32, the switch 965 remains closed under the influence of the coil ill. This keeps the valve in a position delivering the refrigerating medium to the cold storage devices 20. As the temperature in the car rises above 32, the blade lQi releases the contact 689 but this does not affect the switches of group 066 until the blade engages the contact H93 at which time a circuit is com pleted through the switch Hi9 and the coil H91 which results in opening the switch 665 and breaking the circuit through the coil The valve 25 then responds to its bias and shifts the delivery of the refrigerating medium to the direct-cooling coil id in order to apply the full force of refrigerating energy to the car in order to utilize the entire capacity of the refrigerating system to directly refrigerate the car in order to maintain its temperature at or below 34".

It should be understood, of course, that the thermostats may be adapted to have the blades use and 2% thereof engage their contacts E93, use, till, Elli, and at any desired temperature in order to adjust the temperatures at which the controlled devices operate, the specific temperatures mentioned merely being to facilitate the description of the sequential operation of the several elements of the system.

In some cases, it'is desirable to arrange the blowers St to circulate the air within the car when the direct cooling coils ['9 are in operation in order to obtain a maximum cooling effect at such time. This may be accomplished as shown in Fig. l by providing the blowers with a shutter Ziill at the upper end of the conduit to direct the flow of air delivered by the blowers either into the upper end of the conduit or directly out through an opening above the cooling coils 6 9. When the air is thus blown onto the cooling coils, it passes downwardly thereof behind the bulkheads 0d and enters the storage chamber at the bottom through the openings 06. Of course, it is undesirable to operate the heaters when the blowers are in operation to circulate the air past the cooling coil l and so I have shown in Figure 5 of the drawings a schematic Wiring diagram showing the changes and additions which may be made in the araeoaeoe rangement shown in Figure 3 in order to permit the blower motors ME to operate alone when the cooling coils it are in operation and to operate in conjunction with the heaters when it is desired to deliver heat to the storage compartment. It is also desirable to interconnect the heaters and blowers for operation from the external power source and this arrangement also is shown in Figure 5. The heaters and blowers are arranged for parallel operation when powered. from the direct current bus connectors 83 and ti t and means is also provided for operating the motors in series and the heaters in series between one phase of the alternating-current system when the car is stationary.

In Figure 5 of the drawings, the switch groups 9% and I168 are each provided with an additional switch; group i685 having the switch 2H, while group Hi8 has the switch M3. The switch M6 also is provided with circuit-control elements 2 i5, Zlfi, and S il in addition to the circuit control element M5. The circuit control elements M5 and Eli; are adapted to be opened and the circuit element 2m to be closed when the circuit control element M5 is closed. Under the influence of the spring Hill the switches and 2H are normally urged open, and the switches 205 and 2M5 are urged closed. Une side of the control elements EM and 2H are connected together and both are connected by means of a conductor through a switch 229 and the conductor itl to the direct-current bus conductor 83 between the switches and 93. The switch 225? is normally biased toward open position by means of the spring 220. The operating coil M9 of the switch is also connected between the conductors and between the switches and one side of said coil being connected to the common conductor HUG leading to the buss while the other side is connected to the conductor leading through the switch 229' and the conductor Mil to the buss fit. The switch may be closed against its bias when its operating coil is energized. One side of the coil is connected to the direct-current bus conductor between the switches 85 and via the conductor Edi and its other side is connected to one side of both of the switches Elli and 2H3 in parallel, the other sides of said switches being connected in parallel and to the direct-current bus conductor il ivia the conductor idl. The circuit-control elements ti -i5 and H5 also, on one side thereof, are connected together and to one of the conductors its leading to the heating elements ll. The remaining sides of the circuit-control elements M5 and 296 are connected together and to the other of the conductors 639 while the remaining sides of the circuit-control elements 2i and 2M are connected together and, through the conductor 225, to one of the blower motors E li. The other blower motor is connected to the conductor leading to the switch 225?. Each blower control shutter Z'lli is normally urged by means of a spring 22? toward a position in which the corresponding blower delivers a current of air through its cooperating cooling device id but the shutters may be shifted, when their corresponding operating coils 232 are energized, to positions in which the blowers deliver air directly through the heaters it. The operating coils 232 are connected for parallel operation, being preferably in parallel relationship with the heater coils and hence are controlled through the switch its. Whenever the switch H59 closes to place the heaters in operation, the shutter 29? will be pushed against the bias of their springs 221 to direct the air from the blowers through the heating devices.

When the blade 205 engages the contact 203 and opens the switch I59 to discontinue the heaters from operation, the springs 221 will draw the shutters to a position directing air from the blowers onto the cooling coils. The switch 229 is normally open but will be closed by the operating coil 233 when either of the switches 2II or 2I3 is closed in order not only to energize the coil I49 and actuate the switch I46 against the spring I41 to close the contacts I45 and 2I1 and connect the motors MI and heaters M for parallel operation, but also to supply current for driving the motors. The switch 2II will close whenever the blade I9I engages the contact I89 and will open when the blade engages the contact I93, 1. e., when maximum cooling effect is desired. The switch 2I3 also will be closed whenever the blade 205 engages the contact 2UI, i. e., when maximum heating is desired and will open when the blade engages the contact 203. In other words, the blower motors I4I will be actuated whenever the cooling coil I9 is in operation. At the same time, the shutters 201, under the influence of the springs 221, will cause the blowers to direct air against said cooling coils. The blower motors MI also will operate whenever the heaters 4| are in operation but, at such time, the actuating coils 232 will have shifted the shutters 201 against the urge of springs 221 to a position such that the air currents delivered by the blowers will travel past the heating elements and thus deliver warm air into the storage compartment. When the car is stationary and the device operating from an external power source, the switches H5 and 2"; will be closed by the spring I41, thus connecting the blower motors in series and the heating elements in series and both sets together for operation in parallel from one phase of the alternating-current system.

After the external power source is disconnected and the car is in transit the spring I41 of the switch assembly I45 will yield, to permit the circuitcontrol elements 2I5 and M6 to open and the circuit controls I45 and M1 to close and thus isolate the blowers from the heaters and connect the blowers in parallel and the heaters in parallel for operation as heretofore described from the direct-

current buses

83 and 84, whenever the switch 229 closes.

It is though that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form, construction, and arrangement of the several parts without departing from the spirit or scope of my invention or sacrificing any of its attendant advantages, the forms herein described being preferred embodiments for the purpose of illustrating my invention,

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is as follows:

1. In a refrigerating system for traveling vehicles, a cold storage element communicating with a chamber to be cooled, a refrigerant conduit associated with said cold storage element to deliver refrigerating energy thereto for storage for future release to cool the atmosphere in the chamber, a second refrigerant conduit in communication with said chamber and adapted to deliver refrigerating energy directly to the atmosphere of the chamber and means responsive to the temperature prevailing in the chamber and operated by electrical power developed by the movement of the vehicle for controlling the circulation of a refrigerating medium selectively through one or the other of said conduits.

2. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, valve means to control the circulation of said medium in said circulating system selectively to said direct cooling element or the cold storage element, and means for actuating said valve means by electrical power generated by the movement of the vehicle.

3. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for a refrigerating medium, valve means to control the circulation of said circulating medium selectively to said direct cooling element or the cold storage element, and means for actuating said valve means by electrical power generated by the movement of the vehicle when the vehicle is in motion and by electrical power from an external source when the car is stationary.

4. In a refrigerating system for traveling vehicles, the combination of a vehicle, refrigerat-- ing means for said vehicle comprising a direct cooling element, a cold storage element, a system for a refrigerating medium, a valve in said system for controlling the circulation of the refrigerating medium directly to said cooling element or the cold storage element, and thermal responsive means controlled by the temperature in the vehicle to operate said valve by electrical power generated by the movement of the vehicle.

5. In a refrigerating system for traveling vehicles, the combination of a vehicle, refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium, a valve operatively associated in said system for controlling the circulation of the refrigerating medium selectively to said direct cooling element or the cold storage element, electrically operated means actuated by power generated by the movement of the vehicle for actuating said valve, and a thermostat for controlling the operation of said electrically-operated means.

6. In a refrigerating system for traveling vehicles, the combination of a vehicle, refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, a valve operatively associated in said system for controlling the circulation of the refrigerating medium selectively to said direct cooling element or the cold storage element, electrically operated means for actuatingsaid valve, an electrical generator driven by the movement of the ear, and means for delivering power from said generator to said electrically-operated means.

7. In a refrigerating system for traveling vehicles, the combination of a vehicle, refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, a valve operatively associated in said system for controlling the circulation of the refrigerating medium selectively to said direct cooling element or the cold storage element, electrically operated means for actuating said valve, an electrical generator driven by the movement of the car, and means including a control thermostat for delivering electrical power from the generator for the operation of said electricallyoperating means.

8. In a refrigerating system for traveling vehicles, the combinationof a vehicle, refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, a valve operatively associated in said system for controlling the circulation of the refrigerating medium selectively to said direct cooling element or the cold storage element, electrically operated means for actuating said valve, an electrical generator driven by the movement of the vehicle to provide power for said electrically-operated means when the vehicle is in motion, and means to power said electrically-operated means from an external source of electrical power when the car is stationary.

9. In a refrigerating system for vehicles, the combination of a vehicle, having an enclosure to be refrigerated, power-operated refrigerator means comprising a direct coolingelement for refrigerating the atmosphere of the enclosure, a cold storage device, and means for circulating a refrigerating medium including control means for delivering the refrigerating medium selectively to said cooling element or to said cold storage device, and electrically-operated means actuated by electrical currents generated by the movement of the vehicle for operating said control means.

10. In a refrigerating system for traveling vehicles, the combination of a vehicle, a refrigerating apparatus for said vehicle comprising a direct cooling element, a cold storage element, and means to deliver refrigerating energy selectively to said elements, electrical means actuated by the movement of the vehicle for powering said refrigerating apparatus, and means associated with said electrical means and responsive to the prevailing temperaturewithin the refrigerated vehicle for selectively controlling the delivery of refrigerating energy to the cooling element or the storage element.

11. In a refrigerating system for vehicles, the combination of a vehicle, an electric generator driven by the movement of the vehicle, refrigerating means for said vehicle comprising a direct-cooling element, a cold storage element, a compressor, a condenser, electrically-operated means to connect the compressor and condenser selectively in circulating systems including the cooling element and the cold storage element,

' electrically-operated means for cooling the con denser and driving the compressor, electrically operated temperature responsive devices operatively associated with said electrically operated means for actuating the same in response to temperature conditions prevailing within the refrigerated vehicle, and means to deliver electrical power from said generator to the several electrically-operated means.

12. In a refrigerating system for vehicles, the combination of a vehicle, an electrical generator driven by the movement of the vehicle, refrigerating means for said vehicle comprising a direct-cooling element, a cold-storage element, a compressor, and a condenser, electrically-operated means for selectively connecting the compressor and condenser alternately in circulating systems including one the cooling element and another the cold storage element, switching means for powering the electrically-operated means from said generator, electrically-actuated means for driving the compressor and for cooling the condenser, electrical connections including switch means for powering said electrically actuated means from said generator, and temperature responsive devices for selectively actuating the several switch means in response to temperature conditions prevailing within the refrigerated vehicle.

13. In a refrigerating system ,for vehicles, the combination of a vehicle, a direct current electrical generator driven by the movement of the vehicle, refrigerator means for said vehicle, a direct-current motor for driving the refrigerator device when the vehicle is in motion, electrical connection for delivering power from said generator to said motor, an alternating current motor drivingly connected with the refrigerating system and with said direct current motor, electrically operated temperature responsive control means operatively associated with said refrigerating means, and means for powering said alternating current motor from an external power source when the vehicle is stationary whereby said refrigerating means and said electrically operated control means may be actuated by power delivered by said direct current generator when the car is in motion and whereby the refrigerating means may be driven by said alternating current motor and the electrically operated means actuated by electrical power delivered by the direct current motor operating as a generator when the vehicle isstationary.

14. In a refrigerating system for vehicles, the combination of a vehicle, refrigerating means therefor including a cold storage device and including a cooling coil for directly cooling the air within the vehicle, valved means for directing refrigerant selectively through the cold storage device or through the cooling coil, a direct current motor for driving the refrigerating means, a di rect current generator driven by the movement of the vehicle, electrical connections for delivering power from said generator to said motor and to said valved means for actuating the same, an alternating current motor adapted to be energized from a plug-in from an external source of alternating current when the vehicle is stationary, said alternating current motor being drivingly connected with said refrigerating means and said direct current motor whereby to motivate the refrigerating means and drive the direct current motor as a generator to deliver power for actuating the valve means when the vehicle is stationary.

15. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, valve means to control the circulation of said medium in said circulating system selectively to said direct cooling element or the cold storage element, means for actuating said valve means by electrical power generated by the movement of the vehicle, and means to permit actuation of said valve means by electrical power from an external source when the vehicle has stopped.

16. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle, means to circulate refrigerant in said vehicle, said circulating means being driven by electric motors, a source of alternating current for driving said circulating means and an alternative source of direct current for driving the circulating means, one of said sources of current being operative when the vehicle is moving and the other being operative during periods of stoppage, means to connect the motors in series when supplied from the alternating current source, and means alternatively to connect the motors in parallel when supplied from the direct current source.

17. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a direct cooling element, a cold storage element, a system for circulating a refrigerating medium to said direct cooling element and the cold storage element, valve means to control the circulation of said medium in said circulating system selectively to said direct cooling element or the cold storage element, means for actuating said valve means by electrical power generated by the movement of the vehicle, and thermostatic means within the compartment to be cooled, said thermostatic means being connected to control the actuation of said valve means in accordance with temperature conditions in the chamber to be controlled.

18. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a circulating system for a refrigerating medium, a vehicle cooling device, a standby cooling reservoir, means to control said circulating system to actuate said vehicle cooling device to refrigerate the vehicle to a predetermined temperature and to cool said reservoir, generator means actuated by the movement of the vehicle to operate said control means, and means to cut out said generator from the control means circuit when the vehicle stops.

19. In a refrigerating system for traveling vehicles, the combination of a vehicle, power-operated refrigerating means for said vehicle comprising a circulating system for a refrigerating medium, a generator operated by the movement of the vehicle to control the refrigeration within a compartment of the vehicle, a standby source of refrigeration, means to cut the generator out of the circuit when the vehicle stops, and means adapted to be connected to furnish current from an additional source to feed refrigeration from said standby source to the said compartment of the vehicle.

ARTHUR E. DEMPSEY, JR.