US2046894A - Refrigerating apparatus - Google Patents

Description

July 7, 1936. R. R. CANDOR REFRIGERATING APPARATUS Filed Feb. 4, 1935 I N VENTOR.

R a QB p. m M o m K Patented July 7, 1936 UNITED STATES PATENT OFFICE REFRIGERATING APPARATUS poration of Delaware Application February 4, 1935, Serial No. 4,834

3Claims.

This invention relates to refrigerating apparatus and more particularly to a novel system and control'therefor for automatically varying the refrigeration output of the apparatus.

5 Heretofore, in the construction of refrigerators, particularly those comprising a cabinet having a food storage compartment and which are intended principally for household use, in meet-' ing the problem of varying the refrigeration out.- put of the machine to provide substantially constant food preserving temperatures in the cabinet, it has been customary to provide an automatic switch for stopping and starting the refrigerant liquefying unit as by controlling the motor which drives the compressor and to thus operate the apparatus intermittently. With such a method of control. the system, while it is operating, produces refrigeration at a substantially constant rate and the variation in average amount of refrigerant produced over a given period results in variations in the lengths of the period during which the machine operates or is idle. A refrigerating apparatus of this character has certain disavantages, among them being high first cost and frequent service dimculties, together with certain dimculties arising from the continued stopping and starting of the refrigerant liquefying unit, particularly with liquefying units of the compression type.

It is an object, therefore, of the present invention to provide a refrigerating apparatus which is readily adapted to extremely low cost production and in which the difiiculties inherent in an intermittently operated refrigerator are avoided.

It is a further object of the invention to provide a refrigerating apparatus in which automatic control of the output of the apparatus is attained while the refrigerant liquefying unit is constantly running.

It is also an object of the invention to provide a refrigerating apparatus in which the liquefying unit runs continuously throughout a substantial range of room temperatures normally encountered and in which substantially constant temperatures are maintained in the food preserving or other compartment to be cooled solely by controlling the rate of withdrawal of vaporized refrigerant from the evaporator, and to avoid losses which may otherwise be present in such a system of control.

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

In the drawing:

Referring now to the drawing, the figure illustrates a diagrammatic view of a refrigerating 5 apparatus embodying the present invention, a portion of the mechanism being shown in cross section.

In the form of the invention illustrated in the figure, there is provided a refrigerator cabinet indicated diagrammatically at IU forming a food compartment II in which substantially constant temperatures are to be maintained throughout a wide range of room temperatures. For example, in an ordinary household refrigerator, it is desirable to maintain a temperature within the compartment I2 between substantially 42 and 50 F., while room temperatures may run as high as 110 and are generally not below 60 F. Associated with the cabinet I is a refrigerantliquefying unit comprising a compressor I mounted with a motor I 5 in a sealed housing l1, and a condenser I8, all of which may take any of numerous suitable forms in order to maintain a constant supply of liquefied refrigerant for use in the system. Within the compartment l2, there is mounted a refrigerant evaporator it for for cooling the air within the compartment l2, and which may also be provided with means for freezing water as is well known in the art. Suitable means for controlling the flow of liquid refrigerant from the liquefying unit to the evaporator are provided and may comprise a fixed restrictor or other refrigerant control device 20. The elements so far described are connected in series by suitable refrigerant conduits in the well known manner to provide a closed refrigerant circuit. The elements of the refrigerating system including the refrigerant liquefying unit, the liquid refrigerant control device and the evaporator are preferably so proportioned and coordinated with each other as to provide a maximum refrigeration output not substantially in excess of the heat load requirements of the cab- 45 inet under the highest room temperature normally encountered.

In order to provide for a reduction in the out put of the apparatus under conditions at which the maximum output is too great for maintaining proper temperatures within the compartment II, a thermostatically controlled valve 22 is provided in the refrigerant conduit between the evaporator I 8 and the compressor ll. The valve 22 comprises a housing 24 formed with a valve l win-W seat 26 adapted to be opened and closed by a valve 28. The valve 28 is moved between open and closed positions by a bellows 30 acting through a push rod 32, a diaphragm 33 and a yoke 35. The bellows 30 is connected to a thermostatic bulb 34 located in the compartment l2 and when suitably charged with a volatile liquid, acts to open and close the valve 28 in accordance with temperature conditions-within the compartment I2. In order to prevent a loss otherwise entailed in the reduction of pressure and consequent expansion of the refrigerant passing through the thermostatic valve 22, a heat interchanger 36 is provided in the conduit connecting the valve 22 with the compressor I. This causes the refrigerant expanding from the valve 22 to withdraw heat from the liquid refrigerant entering the restrictor 20.

In operation of the apparatus, whenever current is fed to the motor IS, the refrigerant liquefying unit comprising the motor 15, compressor I4 and condenser l6 will remain in operation regardless of the load requirements of the evaporator l8. Refrigerant is compressed in the compressor I 4 and delivered to the condenser l8 where it is condensed to be expanded through the restrictor 20 and vaporized in the evaporator 18. The vaporized refrigerant is withdrawn from the evaporator l8 through the valve 22 to be returned to the compressor H for recompression. When the temperature within the compartment I2 is above the maximum desirable temperature, the thermostatic valve 22 is maintained open by the pressure in the bellows 30, permitting refrigeration to take place at the maximum rate of which the system is capable. As soon as the withdrawal of heat from the air in the compartment l2 by the evaporator I8 has reduced the temperature of the air sufficiently to bring it within the desired range, the bellows 30 begins to contract and to close the valve 22. Thereafter, the withdrawal of vaporized refrigerant from the evaporator I8 is decreased until such time as the valve 22 again opens. It will -be noted that the refrigerant liquefying unit is maintained in continuous operation and that the temperature of the air in compartment I2 is maintained substantially constant notwithstanding the continuous operation of the refrigerant liquefying unit. By this construction, it is possible to provide a refrigerating apparatus wherein the refrigerant liquefying unit runs continuously throughout substantially the entire range of room temperatures normally encountered, although if a thermostatic switch is provided for controlling the motor-compressor I4, its cut-out point may be selected so as to provide intermittent operation of the liquefying unit below any desired room temperature less than maximum. The efficiency of the apparatus while operating at reduced load is maintained by the operation of the heat interchanger 36 which causes the refrigerant expanding from the valve 22 to absorb heat from the warm liquid refrigerant entering the restrictor 20.

Thus, the present invention provides a refrigerating apparatus having means for maintaining the temperature of the compartment to be cooled within a predetermined range, while the refrigerating apparatus for the compartment is maintained in continuous operation.

While the form of embodiment of the present 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 unitary household refrigerating apparatus comprising a cabinet to be cooled, at refrigerant liquefying unit, an evaporator in heat ex change relation to the air in said cabinet, a fixed orifice restrictor between said liquefying unit and evaporator, thermostatic means for controlling the entire flow of refrigerant from the evaporator to the liquefying unit to vary the amount of refrigeration produced by said apparatus while maintaining said liquefying unit in operation whereby to maintain substantially constant temperatures in said cabinet, and a heat interchanger for exchanging heat between the cold gas leaving said thermostatic means and the liquid refrigerant leaving the liquefying unit.

2. A unitary household refrigerating apparatus comprising a cabinet to be cooled, a refrigerant liquefying unit, an evaporator in heat exchange relation to the air in said cabinet, a fixed orifice restrictor between said liquefying unit and evaporator, thermostatic means including a valve for controlling the entire flow of refrigerant from the evaporator to the liquefying unit to vary the amount of refrigeration produced by said apparatus while maintaining said liquefying unit in operation whereby to maintain substantially constant temperatures in said cabinet, and a heat interchanger for exchanging heat betweeen the cold gas leaving said thermostatic valve means and the liquid refrigerant leaving the liquefying unit.

3. Refrigerating apparatus comprising, means forming a space to be refrigerated, an evaporator in heat exchange relation to the air to be cooled for said space, a refrigerant liquefying unit, a fixed orifice restrictor between said liquefying unit and evaporator, an evaporated refrigerant line between said evaporator and liquefying unit, heat exchange means between liquid refrigerant flowing between said liquefying unit and restrictor with refrigerant flowing from said evaporator to said liquefying unit, and a thermostatically controlled throttling valve in said evaporated refrigerant line between said evaporator and said heat exchanger.

' ROBERT R. CANDOR.

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