US2197722A

US2197722A - Refrigerating apparatus

Info

Publication number: US2197722A
Authority: US
Publication date: 1940-04-16
Anticipated expiration: 1957-04-16

Description

p i 6, c. F1 H'ENNEY 2.197.722

. REFRIGERATING APPARATUS Filed March 31, 1934 3 Sheets-Sheet 1 l I I April 16, 1940.

.c. F. HENNEY 2,197,722 REFRIGERATING APPARATUS Filed March 51, 1954 s Sheets-Sheet 2 April 16, 1940. H N 2,197,722

REFRIGERATING APPARATUS Filed March :51, 1954 SSheets-Sheet 3 UUUUUUUUUU: UUUUUUUUU- Gum/um; I

Patented Apr. 16, 1940 UNITED STATES PATENT OFFICE f REFRIGEnA'rrNG APPARATUS Application March 31, 1934, Serial No. 718,323

4 Claims.

condition air in an improved manner with the aid of a refrigerating apparatus in which a refrigerant is evaporated in thermal contact with air to be conditionedand with a holdover durmg periods when the refrigerating apparatus has "excess refrigerating capacity and by refrigerating the air by thermal contact with the holdover when the refrigerating apparatus lacks sufficient capacity to condition the air.

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

In the drawings: 1

Fig. 1 is a view, partly diagrammatic, and partly in vertical cross section of an apparatus embodying features of my invention; V

Fig. 2 is a view, somewhat similar to Fig. 1 showing a modified form of my invention;

Fig. 3 is a View, similar to Fig. 1, of another modification of the invention; r I

Fig. 4 is a cross sectional view of 'a-type of valve which maybe used inpracticing the invention; and

Fig. 5is an enlarged cross-sectional view taken along the line 55 of either Figs. 2 or 3.

In .practicing this invention, a refrigerating system is provided including an evaporator and a refrigerant liquefying unit operatively conorator may include an air coolingfsection I0 and" a holdover cooling section II arranged in series refrigerant flow relationship. The refrigerant liquefying unit may include a compressor I2, condenser I3 and liquid refrigerant receiver I4. The liquid refrigerant from receiver I4 flows through the line or pipe I5, through the expansion device I6, to the evaporator sections In and II, and theevaporated refrigerant returns through line I I to the compressor. I2.

The refrigerant liquefying unit is provided with drivingmeans for driving the same preferably by energy generated through the motion of the car. To this end, a wheel of the car; through the axle I8, belt drive I9, and speed reducing device 20, is drivingly connected with the compressor I2. If desired, although not necessarily, the speed reducing device may be of a character automatically to drive the compressor I2 at substantially constant speeds notwithstanding variations in the speed of the car. However, it is to be understood that many of the advantages of this invention may be derived where the drive between the wheel and the car and the compressor I2 is such as to drive the compressor at varying speeds. The speed reducing device may include a pneumatic clutch 2| which is actuated by air from line 22, connected if desired to the air brake system of the train. In addition the compressor is connected to a stand-by motor 23, to be actuated by current from the station when the train stops by a suitable plug. The solenoid valve 24 actuates the pneumatic clutch 2I in a manner to be more fully described.

In the modification shown in Fig. l, the arrangement is such that liquid refrigerant is maintained in- 'thermal exchange relationship with the air to be cooled and with the holdover while the refrigerant liquefying unit is driven at a sufficient speed to have excess refrigerating capacity. To this end, the evaporator sections Ill and I I are so arranged with respect to each other the" evaporator drops below the predetermined pressure. Preferably the device I6 is so calibrated that the refrigerant temperature is slightly above 32 F. but below the comfort rang of the air to be conditioned. For example,'the refrigerant temperature in the evaporator sections may be 35 F. A thermostatic bulb 25. is placed in contact with the suction line near the outlet of the section I I, and is connected with the expansion device I6 to throttle the same whenever the liquid refrigerant tends to be drawn through the line I1. This arrangement maintainsliquid refrigerant in both sections I0 and II, the level of refrigerant in section II being indicated at 26. Preferably the pipe 21 which discharges refrigerant from section IO'to section II is placed above .tained in the cartridge 28 in section II.

the bottom ofsection II to provide a liquid reis placed in compartment 35 which stops the frigerant pocket in section II. A holdover fluid is placed in cartridge 28 in thermal ex'change relationship with the refrigerant in section II.

When the refrigerant liquefying unit lacks sufficient refrigerating capacity, due to a decrease in speed of the car, or because the car has stopped, the arrangement is such that the air is refrigerated by a thermal contact with the holdover con- This is accomplished by providing means for draining the liquid refrigerant from the section I I and by causing liquid refrigerant in section I to be evaporated by the air, and the vapors thus created to be condensed by thermal exchange with the holdover in cartridge 28, thus transferring heat from the air to the holdover and conditioning the air.

II with the bottom of section III. .This pipe is provided with a valve 30 adapted to be opened when the refrigerant liquefying unit lacks sufficient refrigerating capacity. For example, a speed responsive governor 3|, driven from the wheels of the car is constructed to close the switch 32 whenever the car drops below predetermined speed or stops altogether. When the switch 32 is closed the solenoid valve 30 is opened and the liquid refrigerant in section II is partly or wholly drained into the section I0. When air, under these conditions, is blown over the section III by means of fan 33, liquid refrigerant in section III is vaporized, and the vapor rises through the pipe 21 into thermal contact with the cartridge 28 and is condensed thereby and the liquid thus formed is returned through the pipe 29 to the section ID. This action cools the air as it passes through the section ID by thermal contact with the holdover while the refrigerant liquefying unit lacks sufficient capacity to condition the air.

The holdover fluid in cartridge 28 preferably includes a substance which has an effective phase changing temperature above 32 F. and below the comfort range of air being conditioned. If the evaporator temperature is maintained substantially at 35 F., then the holdover fluid may be a substance which freezes or otherwise changes phase slightly above 35 F. and below the comfort ge of the air to be cooled. The freezing or phase changing temperature should be suificiently low to properly condition the air. Examples of holdover substances which may be placed in the cartridge are:

Dioxan Benzene Nitrobenzene Bromoform Ethylenediamine Ethylenediamine hydrate Dimethyl aniline or the hydrates of the following salts:

or a mixture of butyl stearate with carbon tetrachloride.

The air to be conditioned which enters the fan 33 may come from the interior of compartment 35 which receives the conditioned air, or it may come from the outside atmosphere, or both.

Means for starting and stopping the compressor may be provided. Thus a thermostat 34 A way of accomplishing this is by providing L a drain pipe 29 connecting the bottom of section motor 36 of the fan 33 and also controls the solenoid valve 24 to declutch the compressor from the axle I8. The thermostat 34 is calibrated to stop the motor 36 and compressor I2 at a predetermined low temperature limit and to start them at a predetermined higher limit.

Means are provided to cause the holdover in cartridge 28 to refrigerate the air for compartment 35 when the train slows down or stops and thus cannot drive compressor I2. Thus a second thermostat 31 is provided in compartment 35 which is in series with switch 32. The thermostat 31 controls the solenoid valve 30 in conjunction with the governor 3| to open the drain pipe 29 when the compartment 35 has warmed and the compressor can not be driven at a sumcient speed to provide the necessary refrigeration. The

thermostats

31 and 34 are set at substantially the same temperature limits and when the compartment 35 gets too warm the thermostat 3 opens pipe 29 and thermostat 34 starts fan 33. The air thus driven over section I0 evaporates refrigerant, the vapors of which rise through the pipe 21, condense on cartridge 28 and drain back to section I 0 through pipe 29. Thus the refrigerating power of holdover is used to refrigerate the air when the compressor I2 cannot be driven at a sufficient speed.

When the train is to remain standing for an unusually long time, beyond the refrigerating capacity of cartridge 28, the stand-by motor 23 may be plugged in" to the station current by means of plug 38 and may operate the refrigerating system. If desired, a thermostat 39 may be provided in compartment 35 to start and stop the motor 23 and maintain proper temperatures in compartment 35. The air line 22 may be manipulated by a manual valve, notshown, to declutch the compressor from the axle I8 when the motor 23 is to be energized.

In the modification shown in Fig, 2, the arrangement is such that a holdover of slightly lower phase changing temperature may be used, and in which the refrigerating capacity of the system is primarily utilized to condition air and only excess capacity is used to refrigerate the holdover. Thus a refrigerant liquefying unit is provided, which may be substantially identical with the unit shown and described with respect to Fig. 1. This'refrigerant liquefying unit com-' prises a condenser I311, a compressor 59 and drivtion, the sections 5| and 52 arein parallel refrigerant flow relationship. Thus liquid refrigerant flows through the pipe 53 from the liquefying unit and divides at 54. One path of flow includes a solenoid valve 55 expansion valve 56, evaporator air cooling section 5I, pipe 51 and suction line 58 back to the compressor 59. The expansion valve 56 is provided with a thermostatic bulb 60 substantially similar in construction and action ofthe valve I6 and bulb 20 ofFig. 1. The valve 56 is so calibrated that it maintains a predetermined refrigerant pressure corresponding substantially to 35 F. Another line of flow of the refrigerant includes the pipe 6|, automatic expansion valve 62, evaporator holdover cooling section 52, return branch 64 connected to suction pipe 58. The automatic expansion valve 62 is calibrated to maintain a colder temperature and lower pressure on the section 52 than in the cooling section 5|. For example, it may be calibrated tomaintain a refrigerant temperature of 25 F. A thermostatic bulb 63 controls the valve 62 and prevents liquid refrigerant from being drawn into the compressor.

Means are provided for causing the system to refrigerate air as long as required and thereafter to refrigerate the holdover. Thus a thermostat 65 is provided which governs the fan motor 66, the solenoid valve 55 and the solenoid air valve 61. The calibration is such that when a predetermined low temperature limit is reached, the

'fan 68 and the compressor 59 are stopped and the valve 55 is closed. This is accomplished by causing the thermostat 65, to open the circuit thus deenergizing motor 66 and the solenoids of

valves

55 and 61. These valves, being similar to that shown in Fig. 4, close, thus stopping flow of refrigerant to section 5| and stopping air pressure to clutch 69 which declutches the same. However, a thermostatic switch 10 controlled by bulb "II in holdover I2 is arranged in parallel with respect to valve 61 so that compressor 59 will not stop until the holdover I2 has been properly frozen. As long as the temperature in bulb 1I is above the freezing point of the holdover, the switch 10 remains closed and thus' the compressor is operated to freeze the holdover if the air in the compartment of the car has been cooled.

When the car slows down or stops so that the compressor cannot be driven at sufficient speed, the fins 13 are refrigerated by conduction through the bottom 14 of the holdover tank. The upper part of the fins cool the upper part of the coils I5 of the section 5|. These upper parts of the coils act as condensers for refrigerant standing in the lower parts of the coils. Thus the lower parts of the coils are refrigerated by evaporation of re- Irigerant in the lower parts, the condensation of the refrigerant in the upper parts of the coils and the return by gravity of the condensed refrigerant. It is to be understood that the

valves

56 and 62 may be set to operate at same back pressures, in which case the holdover will be refrigerated simultaneously with the air.

In the modification shown in Fig. 3, the refrigerant liquefying unit I is substantially the same as that shown in Fig. 1. Thus, the refrigerant liquefying unit comprises a condenser I317, a compressor I21: and driving means for the compressor which may be either the live axle IBb or the stand-by motor 23b. A clutch H0 is actuated by air from the line 2217. As explained in the description of the apparatus shown in Figs. 1

and 2, a manual valve (not shown) may be placed in the air line 22b so as to declutch the com-- pres'sor I2b from the axle I8b when the motor 23a is to be energized. The holdover cooling section IM and the air cooling section I02 of the evaporator are in series refrigerant flow relationship; but the refrigerant first flows through the section IM and then through section I02. Thus the liquid refrigerant line I03 from the unit I00 is connected to an automatic expansion valve I04. From there the expanding refrigerant flows through the section II, thence through the pipe. I05 to the section I02 and returns through the suction line I06 to the unit I00, the holdover fluid I01 may be any of the substances heretofore ant commences or continues to flow through the pipe I05 in liquid form and is evaporated in section I02 and the air is conditioned. When the speedof the car reduces or stops, the air is cooled by thermal exchange with the substance I01 through the medium of fins of the type shown in Fig. 5.

The thermostat I08, placedin the compartment to be cooled, stops the fan I09 and declutches the clutch IIO through the action of solenoid valve I I I when the temperature falls below a predetermined minimum, and performs the converse when the temperature rises above a predetermined limit.

The thermostats shown may be made responsive to dry bulb temperatures, wet bulb temperatures or both, as desired.

The solenoid valves in the various modifications may be of the type shown-in Fig.4. --"I'he solenoid I20 lifts the valve member I2I when the solenoid is energized and perm-its it to fall when deenergized.

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

What is claimed is as follows:

1. An air conditioning apparatus comprising a phase changing holdover a refrigerant evaporator and a refrigerant 'liquefyi'ng unit operatively connected together, said evaporator including an air cooling section and a holdover cooling section said sections being in series refrigerant flow relationship with the refrigerant first entering'the air cooling section, means for thermally exchanging heat between air to be conditioned and said air cooling section when said refrigerant liquefying unit has excess refrigerating capacity and means for thermally exchanging heat between air to be conditioned and said holdover through the air cooling section of said evaporator when said unit lacks sufiicient refrigerating capacity.

2. An air conditioning apparatus comprising a phase changing holdovera refrigerant evaporator and a refrigerant liquefying unit operatively connected together, said evaporator including an air cooling section and a holdover cooling section, said sections being in series refrigerant flow relationship with the refrigerant first entering the air cooling section, means for thermally exchanging heat between air. to be conditioned and said air cooling section when said refrigerant liquefying unit has excess refrigerating capacity and means for draining liquid refrigerant from said holdover cooling section to said air cooling section when said unit lacks sufficient refrigerating capacity.

3. An air conditioning apparatus comprising a phase changing holdover a refri erant evaporator and a refrigerant liquefyingunit operatively connected together, said evaporator including an air cooling section ,anda holdover cooling section in "series refrigerant fiow relationship with the refrigerant entering said air cooling section first,

means for'inaintaining-liquid refrigerant in said relationship with said holdover cooling section, means maintaining liquid refrigerant in both said 10 sections when said car generates suflicient energy to operate said liquefying unit with sumcient refrigerating capacity to condition air and refrigerate said holdover, and means draining liquid refrigerant from said holdover cooling section when said car does not generate suflicient energy to operate said liquefying unit with sufiicient refrigerating capacity to condition air and refrigerate said holdover independently of the quantity of liquid refrigerant in saidevaporator.

CHARLES F. HENNEY.