US2052894A - Refrigerating apparatus - Google Patents

Description

Sept. 1, 1936. D. H. REEVES 2,052,894

' REFRIGERATING APPARATUS Original Filed April 16, 1930 2 Sheets-Sheet l W W 141E032? Sept. 1, 1936. D H V 2,052,894

REFR IGERAT ING APPARATUS Original Filed April 16, 1930 2 Sheets-Sheet 2 IN VENT OR Patented Sept. 1, 1936 UNITED STATES REFRIGERATING APPARATUS Donald H. Reeves, Dayton, Ohio, assignor, by Y mesne assignments, to General Motors Corporation, a corporation of Delaware Application April 16, 1990, Serial No. 444,639 Renewed May 13, 1935 9 Claims. (01. 236-92) This invention relates to refrigerating apparatus and more particularly to the control of such apparatus. v

An object of this invention is to provide an improved refrigerating system in which the cooling I action of the evaporator is controlled by variation in pressure in a fluid container, and to provide for varying the pressure range of the fluid in the container.

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

In the drawings:

Fig. 1 is a view in cross section of a portion of a refrigerating apparatus and showing features embodying the invention. 1 a

Fig. 2 is a longitudinal sectional view of the expansion valve and compensating device forming a part of the invention; and

Fig. 3 is a diagrammatic view of the refrigeratins system.

Referring to the drawings, there is shown a cabinet comprising a cooling compartment 2| and a machine compartment 22. The cabinet is arranged for housing a refrigerating apparatus in the compartments 2| and 22. These compartments are separated by a wall 21. A cool- .ing unit is carried by and'below the wall 21 and extends within the cooling compartment, and a compressor 32, driving motor 33 and condenser 35 are carried by -or on top of said wall.

Referring more in detail to the drawings and particularly to Fig. 3, the refrigerating apparatus 25 comprises the refrigerating element or cooling unit 30 having an outer coiled pipe 31 for cooling the compartment 2| and having an inner coiled pipe 38 in thermal contact with a freezing compartment 40 adapted to receive a plurality 'oficemaking receptacles 4|. The cooling unit is supplied with liquld'refrigerant under the control of an expansion valve from a receiver 41. Refrigerant evaporated in the cooling unit is withdrawn by the compressor 32 actuated by the threaded in a yoke Bl surrounding the inlet and supported on a flexible metal diaphragm which forms one wall of the chamber 5|, being clamped between the casing 5|! and end plate 62 by bolts 64. A removable plug- 65 affords access to the chamber 5| for adjusting the valve. The end plate 62 provides a chamber 61 on the back side of the diaphragm 60. The diaphragm 60 is acted upon by the force of the pressure in the chamber 61 which tends to open the valve and the force of the pressure of the refrigerant-in the valve chamber which tends to close the valve. Whenever the compressor is running it reduces the pressure in the valve chamber and permits the valve to open. The re- 5 frigerant expanding upon entering the valve chamber tends to increase the pressure and consequently tends .to close the valve. Thus, when the pressure in the chamber attains a certainlow value, the valve will be moved from its seat to 20 admit more refrigerant to the chamber 5| and likewise to the evaporator 30. Conversely, when the pressure in the chamber 5| attains a certain high value, the valve will close to shut off the flow of refrigerant to the evaporator. Thus it is 25 apparent that, during the operation of the system, valve 45 normally tends to maintain a constant pressure within the evaporator 30.

It is desirable to maintain the back side of the diaphragm covered at all times to prevent moist 30 air from circulating or entering the chamber ill on the back side of said diaphragm. If air were permitted to circulate inback of the diaphragm, frost would collect thereon and this frost would materially affect the operation of the valve. Merely sealing the back of the diaphragm will not entirely remove defects, due to changes in operation of the valve, because the air in back of the diaphragm will be chilled and, due to the back side being sealed, the pressure on the back side will decrease. Hence under certain conditions,

- for example, at the start of the refrigerating cycle, when the valve is relatively warm, relatively high pressure is present in back of the diaphragm, and, after the refrigerating cycle has continued for awhile, the valve will be colder and a lower pressure is present back of the diaphragm. These changes in pressure often cause a decrease in efflciency of operation.

In order to cause the valve 55 to function more correctly under varying conditions, a compensating or governing device has been provided for controlling the pressure in the back of the diaphragm. This device is herein shown as comprising an 7 adjustable fluid container comprising a tube 16 55 and a bulb 15 in the form of a sylphon or bellows. The bulb I5 is sealed to the back side of the diaphragm by the tube 16 and connection IT. This bulb is disposed outside of the zone of direct coolinginfluence of the evaporator and is herein shown located within the machine compartment 22 and held in place by a bracket 80. By using the bulb, not only the air in the back of the diaphragm, but also the air in the bulb and tube 16 must be chilled before the pressure on the back side of the diaphragm will be decreased. And, it is readily apparent that any desired pressure may be obtained in back of the diaphragm. For example, the bulb may be placed in such location within the machine compartment so that the temperature of the fluid within the bulb will be increased artificially. The bulb may be filled with any suitable fluid, and for instance at atmospheric pressure, and preferably, for practical purposes, it has been found desirable to maintain air in the bulb and to carry. saidbulb as shown, in which the bulb is subjected to environment temperatures within the machine compartment 22, which temperature will be ordinarily a little higher than room temperature.

It is desirable to vary the pressure in the fluid container in order to control. the pressure at which the valve opens and it may be desirable to change this adjustment to suit certain operating conditions. Thus, in the event it is desired to vary the pressure on the back side of the diaphragm in order to vary the pressure in the evaporator 30, I have provided means for expanding or contracting the adjustable fluid containing bulb 15. This means may comprise a screw 90 threaded into an inwardly directed boss 92 formed on a sealing ring 93 which forms one end of the bulb-l5. By this arrangement the screw 90 normally maintains the expansible bulb 15 in a fixed position, and by a movement of screw 90 the bulb may be expanded or contracted. Thus by turning the screw 90, the adjustable fluid containing bulb may be compressed or expanded to change the pressure of the air in said bulb, tube 16 and chamber 61 to either super-atmospheric or sub-atmospheric pressure as desired. This arrangement is meritorious in that the pressure on the back side of the diaphragm may be varied without unsealing the bulb or its connection to the back side of the diaphragm. Thus, it is possible to adjust the compensatingdevice to vary the pressure on the back side of the diaphragm without the possibility of air circulating about the back side of the diaphragm when the temperature of the diaphragm is such that moisture would collect on the backside thereof. Thus the bulb, tube 16 and chamber 51 may be filled with air, sealed and adjustments made to vary the pressure on the back side of the diaphragm without affecting the emciency of the valve. Also, this arrangement is advantageous since the bulb may be disposed in a ready accessible place so that adjustments thereof may be easily made.

From the foregoing it can be seen that the refrigerating system will operate at a higher. back pressure in warm weather or in a warm room than in relatively cold weather or room, because a higher pressure will be maintained in back of the diaphragm in the warm environment. This feature of the invention is meritorious in that a relatively high back pressure is desirable in warm weather and -a lower back pressure is desirable in colder weather; since, as well understood, higher efficiency is attainable with a relatively high back pressure and much higher efliciency is most desirable in warmer temperatures because of greater heat leakage through the cabinet walls. If a refrigerating apparatus is operated at a relatively high back pressure in colder weather, the temperature of the cooling unit is reduced quickly because the heat leakage through the cabinet is relatively small. Therefore, the period for freezing is relatively small. Moreover, the refrigerating phases do not take place as frequently in cold weather as in warm weather because there is less heat leakage through the cabinet, consequently the water in the receptacles ll will not be frozen as quickly in colder weather. Therefore, it is desirable to prolong the refrigerating phase in colder weather and this can be accomplished by reducing the back pressure in the system. The governing device herein shown regulates the back pressure automatically to produce the desired results, because, as the environment temperature falls, the pressure within the bulb 15 decreases and less force is applied to the back side of the diaphragm. Therefore, a lower pressure must be produced in the evaporator and in the expansion valve 45 before the valve 55 opens.

Thus it is apparent that the governing device herein shown causes the system to function properly under different climatical conditions, in that the valve and bulb may beadiusted to automatically maintain the desired back pressure for efficient operation in warm weather and provides for quickly freezing or congealing substances in colder weather. Thus the refrigerator will operate efflciently irrespective of the climatical conditions.

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. A refrigerant expansion valve including a valve chamber having an inlet and an outlet, a valve for controlling the flow of refrigerant through the valve chamber, a diaphragm connected to operate said valve, 9. fluid chamber on one side of said diaphragm, a thermostatic bulb connected to said fluid chamber, said fluid chamber and said bulb containing a gas non-condensible at operating temperatures and means for varying the pressure in said fluid chamber.

2. A refrigerant expansion valve including a .valve chamber having an inlet and an outlet, a

valve for controlling the flow of refrigerant through the valve chamber, a diaphragm connected to operate said valve, 9. fluid chamber on one side of said diaphragm, a thermostatic bulb connected to said fluid chamber, said fluid chamber and said bulb containing a gas non-condensible at operating temperatures and means for varying the volume of said thermostatic bulb.

3. A refrigerant expansion valve including a valve chamber having an inlet and an outlet, a valve for controlling the flow of refrigerant through the valve chamber, a diaphragm means subject to refrigerant pressures within said valve chamber for operating said valve responsive to said pressures, and fluid pressure means containing a gas which does not change its state at operating temperatures for loading said diaphragm means and for regulating the movement thereof, said fluid pressure means including means for adjusting the pressures within said valve chamber having an inlet and an outlet,

statically regulating the loading of said diaphragm by fluid pressures, said fluid pressure means including means for varying the volume thereof for adjusting the fluid pressures therein.

5. A refrigerant expansion valve including a valve chamber having an inlet and an outlet, avalve for controlling the flow of refrigerant through the valve chamber, a diaphragm means subject to refrigerant pressures within said valve chamber for operating said valve, and thermostatic fluid pressure means containing a gas which does not change its state at operating temperatures operatively connected to said fluid pressure means, said fluid pressure means including a thermostatic bulb operatively connected to the diaphragm means for regulating the loading of said diaphragm means by the fluid pressure means, and means for varying the volume of the fluid pressure means for adjusting the loading of said diaphragm means by the fluid pressure means.

6. A'refrigerant expansion valve including a valve chamber having an inlet-and an outlet, a valve for controlling the flow of refrigerant through the valve chamber, a diaphragm means subject to refrigerant pressures within said valve chamber for operating said valve, and thermostatic fluid pressure means containing a gas which does not change its state at operating temperatures operatively connected to said fluid pressure means, said fluid pressure means including a thermostatic bulb operatively connected to the diaphragm means for regulating the loading of said diaphragm means by the fluid pressure means, and means for varying the volume of said thermostatic bulb.

7. A refrigerant expansion valve including a valve chamber having an inlet and an outlet, a valve for controlling the flow of refrigerant through said valve chamber, and thermostatic fluid pressure means containing a gas which does not change its state at operating temperatures for thermostatically regulating said valve, said fluid pressure means including means for vary- I ing the volume thereof for adjusting the fluid pressures therein.

8. Refrigerating apparatus including an evaparating means and means for circulating refrigerant through the evaporating means, and thermostatic fluid pressure means containing a gas which does not change its state at operating temperatures for controlling the circulation of refrigerant through the evaporating means, said fluid pressure means including means for vary- 4 ing the volume thereof for adjusting the fluid pressures therein. 1

9. A refrigerant expansion valve including a valve chamber having an inlet and an outlet, a valve for controlling the flow of refrigerant through said valve chamber, means for controlling said valve including means responsive to the pressure within said valve chamber and thermostatic fluid pressure means containing a gas which does not change its state at operating temperatures for thermostatically regulating said valve, said fluid pressure means including means for varying the pressure therein to vary the control of the valve.

DONALD H. REEVES.

CERTIFICATE OF CORRECTION.

Patent No. 2,052,894. September 1, 1956 DONALD H. REEVES.

It is hereby certified that error appears in the printed specification of the above. numbered patent requiring correction as follows: Page 5, first column, line 20-21, claim 5, and line 37-38, claim 6, for the words "fluid pressure" read diaphragm; and that the said Letters Patent should be read with these corrections therein that; the same may conform to the record of the case in. the Patent Office;

Signed and sealed this 20th day of October, A; 'D. 1956.

- Leslie Frazer (Seal) Acting Commissioner of Patents.

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