US2318893A - Refrigerating apparatus - Google Patents

Description

May 11, 1943. H, E SMITH 2,318,893

' REFRIGERATING APPARATUS Filed Nov. 22, 1939 2 sheets-sheet 1 2 76 .98082 92 747 l .aUl o I 0 0 0 j. a 76 I; o 86 90 E22 o k 40 r 32.

ATTORNEYS.

y 1 1943. .H. i SMITH 2.3185 93 REFRIGERATING APPARATUS ATTORNEYS.

?atented May 11, 1943 so STATE REFRIGERATING APP TUS Harry F. Smith, rename, one, assignor to General Motors Corporation, Dayton, Ohio, a corporation of Delaware which is suitable for mounting in a small space such as ordinarily available'in a railway car.

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 or the present invention is clearly shown.

In the drawings:

Fig. l. is a plan View with parts broken away showing the general arrangement oi" the conditioning apparatus;

Fig. 2 is a. fragmentary sectional view showing the speed control and Fig. 3 is a sectional elevational view with parts broken away showing a modified arrangement with a modified control system.

In designing a refrigerating system for use in railway cars, warehouses and thelike, it is necessary to provide a system which has ample refrigeration capacity for the hottest weather encountered and which is capable of malnta the temperature within a predetermined range even when the outdoor temperature is colder than the desired indoor temperature. This is especially necessary in freight car installations since it frequently happens that freight cars are used in transporting perishable products from warm climates where cooling alone is necessary to colder climates where at least a small amount of "heating is required. .In certain climates cooling alone is necessary except for a few cold days during the year when a small amount of heat ing is required. For purposes of illustration, 1 have shown these systems applied to a railway car adapted for transporting perishable coeds which require uniformly cool temperatures.

Referring to Fig. l, which is a plan view showing my apparatus mounted in. the end compartment of a refrigerated car it, the refrigerating system comprises an evaporator l2 mounted in a-cooling chamber it, and refrigerant licueiying apparatus comprising a condenser it, a re,- ceiver l8, and a compressor I9, all mounted in the machine compartment 20. The refrigerant evaporated inthe evaporator i2 flows through the vapor line 22 into the compressor it which compresses the refrigerant and discharges the compressed refrigerant through the line 25 leading to the condenser it. Refrigerant condensed by the condenser I6 flows through the line 26 to the liquid refrigerant receiver it whence it flows through the line 23 into the evaporator 12. The flow of liquid refrigerant from the re-' ceiver l8 to the evaporator 82 is controlled by means of the usual form of thermostatic espam.

sion valve 27 placed in the liquid line 28.. This thermostatic expansion valve 2t is provided with a thermostat 30 in thermal exchange with the vapor line 22 so as to automatically throttle the flow of refrigerant to the evaporator in the event that liquid refrigerant spillsovcr into the vapor line 22.

Air from the storage compartment 32 iscirculated over the evaporator ill by means of the fan 3t which withdraws air from th compartment at through the opening 35 and discharges the conditioned air into the compartment 82 through the outlet 38. The compressor it is driven by the Diesel engine which is provided with the usual flywheel (it? and exhaust pipe 538. A conventional electric starter lid is. provided for starting the Diesel engine. The flywheel 62 is provided with gear teeth so which mesh with the pinion 58 of the water circulating pump 58. The pump circulates'ccoling water for the engine through the engine radiator E52. With the arrangement shown in this modification, the Dieselengine is normally operated continuously while the car is in use. and therefore no special circuit is necessary for automatically starting and stopping the Diesel engine. The starter it, therefore, may be manually controlled. In order to causecirculation of air over the condenser it, the compressor it, the Diesel engine to and the engine radiator 52, I have provided a fan 5% which normally draws outside air in through the opening 56' at the one side of the car and discharges the heated air through the opening ttfldisposed on the opposite side of the car. The speed of the Diesel engine is controlled by means of a thermostat to which, for purposes of illustration, has been shown as mounted in the storage compartment 32. In order to simplify this description, all controls will he referred to as thermostats; however, humidistats or efiective temperature responsive instruments may be substituted therefor. As the temperature in the space 32 increases, the speed of the Diesel engine is caused to increase so as to increase the refrigeration capacity of the refrigerating system. Inasmuch a it sometimes happens that it is necessary to.supply heat to the storage compartment rather than cooling the storage compartment, I have provided a set of dampers G2 and Ed which when open permit a portion of the air from the compartment 32 to pass over the condenser IS, the compressor I9, the Diesel engine til, the radiator 52, evaporator I2, and thence through the outlet 38 leading to the storage compartment.

Inasmuch as the amount of heat given off by the Diesel engine depends in part upon the load placed on the engine, and inasmuch as the load on the Diesel engine is ordinarily the least when the least amount of cooling is required and the outside air is at a low temperature, it is desirable to provide means for conserving on the heat generated by the Diesel engine and, in fact, increasing the heat generated by the Diesel engine under certain conditions when a greater amount of heat is required. In order to increase the amount of heat available for heating the storage compartment, I have provided a thermostat -66 for automatically controlling the dampers 60, 58, B2 and 64. When the temperature of the air passing over the thermostat S6 is not sumciently warm, the thermostat 66 causes the dampers 56 and E to at least partially close and the dampers 62 and M to open a corresponding amount. In other words, when it is desirable to add heat to the air in the compartment 32, the dampers 62 and 6d are opened and the dampers 56 and 58 are closed sufiiciently to make available additional heat. 7

The extent of movement of the various dampers will be determined'by the temperature of the air surrounding-the temperature responsive element 66. The element 66 actuat'es the dampers through the pivoted lever 61 which operates the damper operating cords 60.

By virtue of the above described arrangement the load on the engine is increased since the circulation of hot air from the engine compartment over the evaporator I2 increases the load on the compressor. By increasing the load on the engine in this manner the temperature of the air delivered to the compartment 32 is increased. This arrangement also prevents frost-up of the evaporator at such times when the air in the compartment 32 is at a low temperature.

It will be observed that a certain amount of in- Q tel-mixing of fresh air and recirculated air will take place when the dampers are moved from the position shown in Fig. 1 to a position intermediate fully open and fully closed position. Some of this fresh air will find its way into the compartment 32 as a result thereof. Consequently, when damper 64 is partly open and damper I0 is only partly closed, the temperature of the outside air will partly determine the temperature of the.

air circulating overthe member 88 and to this extent the temperature of the outdoor air will influence the operation of the refrigerating apparatus. i

In Fig. 2 I have shown the engine throttling mechanism I0. As shown therein, variation in temperature at 00 causes reciprocation of the extensible slide member 12 which oscillates the cam 14 by means of the pin and slot connection II. The com I4 is mounted to oscillate about the fixed pivot ll.- Tne cam I4 actuate: the follower II which is slidably mounted on the bracket 00.

The follower I8 is provided with a shoulder element is which acts against the spring 82 which when compressed serves to load the centrifugal governor a l in a well-known manner. The governor controls the engine throttle 88 through the lever arrangement 86. Fig. 2 shows the cam actuator It in the position it occupies when the storage space 32 requires little or no refrigeration As the temperature at the bulb 60 increases indieating need for more refrigeration. the cam It is rotated in a clockwise direc ion with the result that the engine throttle ri ened a greater amount so as to speed up the Diesel engine. As the temperature within the compartment recedes the cam element It rotates in a counterclockwise direction, thereby serving to slow down the Diesel engine. However, the Diesel engine cannot be slowed down beyond a certain speed; and if by slowing down the engine to this minimum speed too much cooling still takes place, the thermostat EEG will operate the necessary dampers to add heat to the compartment and in the event that this alone is not enough to maintain proper temperatures in the compartment 32 and the temperature drops below a safe level, the cam It will be rotated far enough to lift the cam follower I8 onto the high surface 90 which materially increases the speed of the Diesel engine so as to further increase the heat given off by the engine. As the temperature within the compartment 32 increases to a predetermined value at which maximum heating is no longer required. the thermostat 60 will operate the cam M so as to slow down the Diesel engine until such time when either more cooling or more heating is required. For purposes of illustration, the thermostat 60 has been shown located in the compartment 02: however, it is within the purview of this invention to place the thermostat 60 in any other location, such as at the discharge side of the evaporator in the compartment I 4 or on the outside of the car. Likewise, the thermostatic'element 68 may cars, however, is the arrangement shown.

In Fig. 3 I have shown, in modified form, air conditioning apparatus in which air from the compartment I00 enters the plenum chamber I02 through the air intake opening I04 and is circulated by the fan I08 over the evaporator I08 and then is returned to the compartment I00 through the discharge opening 0. For. purposes cf illustration, the air intake has been shown in the upper portion of the car and the conditioned air outlet has been shown as being arranged adjacent the lower portion of the car; however, other well-known air duct arrangements may be used in which the conditioned air, for example, may be discharged into the upper part oi the car.

The refrigerating system comprises a compressor II2 which withdraws evaporated refrigerant from a. main evaporator I00 and an auxiliary evaporator I00 and discharges compressed refrigerant to a main condenser Ill and the auxiliary condenser IIB. The refrigerant thus condensed flows to the liquid receiver IIO whence liquid refrigerant is supplied to the evaporator-a I00 and I00. The flow of liquid refrigerant from the receiver III to the evaporator II! is controlled by means of a thermostatic expansion valve I20 located in the liquid lino I22. The valve I20 is provided with a thermostatic bulb when liquid refrigerant reaches the outlet of the evaporator. The flow of refrigerant from'the receiver lid 'to the evaporator I09'is controlled by'means of expansion valve I 20 which is set to open only at a pressure somewhat lower than the pressure at which thermostatic expansion valve I20 opens. The valve I20 is normally closed except at such times when the cooling load in the compartment I is so low that little or no refrigerant is being evaporated in the evaporator I00 whereby a portion of the liquid refrigerant reaches the bulb I at which time the valve I20 tends to close with the result that the suction pressure decreases enough to open the valve I20.

The compressor I I2 is driven by the Diesel en= glne I30, the speed of which is' controlled by the thermostatic bulb I32 disposed in thermal exchange with the auxiliary evaporator I'00 and they auxiliary condenser I I 0. The arrangement is such that the Diesel engine operates at a high speed when the temperature at bulb I32 is high, and as the temperature at I32 decreases due to the opening of the valve I20 the speed of the engine will bedecreased so as to reduce the amount of refrigeration supplied. The engine is never stopped completely as will be explained hereinafter. With the valve I20 closed the thermostat I32 will be maintained warm by the auxiliary condenser I I6, but as refrigerant is supplied to the auxiliary evaporator I09 the temperature at the thermostat I32 is decreased. The thermostat I32 acts on a speed regulator I0 of the type shown in Fig. 2. The Diesel engine I is water cooled by means of the radiator I00 and the water circulating pump I30. Outside air is caused to circulate through the machinery compartment by the blower I00.- The air which circulates through the machinery compartment normally discharges to the outside of the car through the opening I02, at all times when cooling is required. However, if the temperature in the space I00 drops below the desired value, a portion or all of the heat generated in the machinery compartment is discharged into the plenum chamber I02 through the opening I 00. When heated air is discharged into the space I00 the increased pressure in the space I00 causes air from the space I00 to return I to the machinery compartment through the vent I03 whereby little heat is lost. I

The flow of air through the openings I02 and I00 is controlled by the dampers M0 and I00 respectively, and these dampers in turn are controlled by means of the thermostat I which for purposes of illustration has been shown located adjacent the discharge opening IIO. By placing the thermostat I50 adjacent the discharge open-- ing IIO the temperature of the air discharged into the compartment 1 I00 is controlled so as to prevent too cold air from being discharged intothe compartment I00. The thermostat I50 could be located directly in the compartment itself; rather than in the discharge air stream, if desired.

The blowers I06 and I00 are both mounted on the Jackshaft I52 which is driven by the Dieselengine by means of the belt arrangement I00. The

Diesel engine is provided with a starter I which is under control of the manual switch I50. As pointed out in connection with the description of the first modification, there are times when the outdoor temperatures are-so low that the heat generated by the Diesel engine and the condenser are insumcien't' to supply the necessary amount-of heat required inland-compartment I00. In order to make available a greater amount of heat, I

have provided a damper I00 which controls the The thermostat I 62 is adjusted to prevent the engine from becoming too cool for emcient operation. Inasmuch as the heated air passing through the machinery compartment is used for heating the compartment I00, I have provided a filter I64 which filters all of the air entering the blower I 40.

A damper I33 under control of the water thermostat I35 controls the flow of air over the radiator I 34 so as to maintain the engine cooling water at an efllcient'temperature.

The speed of the engine I I2 could be controlled in the same manner in which the speed of the engine 00 is controlled, if desired, in which case the evaporator I09 and condenser II6 would be omitted. -With either arrangement the engine is intended tooperate continuously even though the correct temperature exists in the conditioned space. I

It is apparent, therefore, that I have provided a system which is capable of maintaining proper conditions within. the conditioned space irrespective of outside temperatures.

From the above described arrangement it is apparent that the torque control is had by the use of a centrifugal governor driven by the en gine which, by its action varies the amount of fuel injected at each stroke to correspond to the torque load. This keeps the engine turningyat constant speed while the torque, or resistance to turning, changes from zero to maximum. The.

,gine will, consequently, come to full speed and the fans will force a full flow of air through the evaporator as well as through the condenser.

As the temperature within the space I00 begins to decrease, the low side pressure will decrease somewhat and the expansion valve bulb I20 will restrict the flow of liquid refrigerant to keep the evaporator properly filled with liquid in the wellknown manner but by virtue of the large volume of warmer air over the evaporator I08 the low side pressure will remain relatively high, thereby causing the engine to operate at full speed. As.

the temperature in the space I00 decreases still further, the air returning to the evaporator will be still cooler and will cause less refrigerant to evaporate. Gradually. thelow side pressure will start to fall and the sensitive pressure relay I20 will begin to remove loading from the centrifugal governor, thereby slowing down the engine. When the amount of heat removed by the refrig .erator equals the heat leaking into the space I00 the speed of theengine will become steady and uniform refrigeration will result. Inasmuch as the engine will not operate below a predetermined minimum speed, heat must be added viathe dampers I00 in the event that the tempera-.

ture of the air passing over thermostat I50 drops below a predetermined value. At minimum speed of the engine very little heating would normally be available, so whenever heating is required at ieast a portion of the heated air must be over the evaporator before its being discharged into the compartment i so as to further load the en- I gine.

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 evaporators and discharge the compressed refrigerant into said condensers, a prime mover for operating said compressor, a thermostat in thermal exchange relationship with said auxiliary evaporator, and means operated by said thermostat controlling the speed of said prime mover.

2. In combination, a main evaporator, an auxiliary evaporator, a main condenser, an auxiliary condenser in thermal exchange relationship with said auxiliary evaporator, a compressor, refrigerant flow connections whereby said compressor is adapted to withdraw refrigerant vapor from said evaporators and discharge the compressed refrigerant into said condensers, a prime mover for operating said compressor, -a thermostat in thermal exchange relationship with said auxiliary evaporator, means operated by said thermostat controlling the speed of said prime mover, a first pressure responsive valve controlling the flow of. refrigerant to said main evaporator, and a second pressure responsive valve controlling the flow of refrigerant to said auxiliary evaporator,

one of said valves being set to operate at a lower.

pressure than the other valve.

3. In combination, an evaporator, refrigerant liquefying apparatus for supplying liquid refrigerant to said evaporator comprising a compressor, a condenser, and an internal combustion engine for operating said compressor, means for circulating'air to be conditioned for an enclosure in thermal exchange with a portion of said liquefying apparatus, means for simultaneously circulating air to be conditioned for said enclosure in thermal exchange with said evaporator, and means responsive to a predetermined low temperature for increasing the amount of liquid refrigerant supplied to said evaporator.

4. In combination, an evaporator, refrigerant liquefying apparatus for supplying liquid refrig erant to said evaporator comprising a compressor, a condenser, and an internal combustion engine for operating said compressor, means for circulating air to be conditioned for an enclosure in thermal exchange with said internal combustion engine and said condenser, means for simultaneously circulating air to be conditioned for said enclosure in thermal exchange with said evaporator, and means responsive to a predetermined low temperature for increasing the amount of liquid refrigerant supplied to said evaporator.

5. In combination, an evaporator, refrigerant liquefying apparatus for supplying liquid refrigerant to said evaporator comprising a compressor, a-condenser, and an internal combustion engine for operating said compressor, means for circulating air to be conditioned for an enclosure in thermal exchange with a portion of said liquefying apparatus, means for simultaneously circulating air to be conditioned for said enclosure in of said liquei'ying apparatus.

, adopted, all coming within the scope of the claims 6. Air conditioning apparatus comprising in combination, an evaporator, refrigerant liquefy ing apparatus including a compressor, a con" denser, and a prime mover for said compressc r, refrigerant flow connections between said evaporator, compressor and condenser, means for circulating air to be conditioned for an enclosure in thermal exchange with said evaporator, means for circulating outside v air in thermal exchange with a portion of said .l'iquefying apparatus, first temperature responsive means controlling the op eration of said prime mover, second temperature responsive means controlling the flow of outside air over said liquefying apparatus, means for circulating at least a portion of the air circulating over said liquefying apparatus into thermal exchange with said evaporator and thereafter into said enclosure, and means responsive to the temperature of the conditioned air for controlling said last named means.

7. Air conditioning apparatus comprising in combination, a volatile refrigerant evaporator, refrigerant liquefying means for supplying refrigerant to said evaporator; said refrigerant liquefying means comprising a compressor and an internal combustion engine for operating said compressor; heat dissipating means; means for transferring heat from said internal combustion engine to said heat dissipating means; and means for flowing air to be conditioned into thermal exchange relationship with said heat dissipating means so as to heat said air and thereafter into thermal exchange relationship with said evaporator so as to recool said air.

8. Air conditioning apparatus comprising in combination, a volatile refrigerant evaporator, refrigerant liquefying means for supplying refrigerant to said evaporator; said refrigerant liquefying means comprising a compressor and an internal combustion engine for operating said compressor; heat dissipating means; means for transferring heat from said internal combustion engine to said heat dissipating means; means for flowing air to be conditioned into thermal exchange relationship with said heat dissipating means so as to heat said air and thereafter into thermal exchange relationship with said evaporator so as to recool said air; and means for increasing the flow of refrigerant to said evaporator in response to an increase in the heating reguirements whereby the load on said internal combustion engine is increased.

9. Air conditioning apparatus comprising in combination, an evaporator, refrigerant liquefying apparatus including a compressor, a condenser, and a prime mover for said compressor, refrigerant flow connections between said evaporator, compressor and condenser, means for circulating air to be conditioned for an enclosure in thermal exchange with said evaporator, means for circulating outside air in thermal exchange with a portion of said liquefying apparatus, first temperature responsive means controlling the operationof said prime mover, second temperature responsive 'means controlling the flow of outside air over said liquefying apparatus, and means for circulating at least a portion of the air circulating over said liquefying apparatus into thermal exratus, means for simultaneously circulating air to be conditioned for said enclosure inthermal exchange with said evaporator, and means responsive to a predetermined low temperature for increasing the amount of liquid refrigerant supplied to said evaporator.

11. Apparatus for either heating or cooling air for an enclosure comprising in combination, an

evaporator, refrigerant liquefying apparatus comprising a compressor, a condenser, and an internal combustion engine for operating said compressor, refrigerant flow connections between said evaporator, compressor and condenser, means for circulating air from said enclosure in thermal exchange with at least a portion of said refrigerant liquefying apparatus and said evaporator in series, means for by-passing said refrigerant liquefying apparatus with at least a portion of said air, and means for flowing outside air in thermal exchange with said portion of refrigerant liquefying apparatus and for discharging said last named air to the outside.

HARRY F. SMITH.

Images