US3023589A

US3023589A - Refrigerating apparatus

Info

Publication number: US3023589A
Application number: US853084A
Authority: US
Inventors: James W Jacobs
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1959-11-16
Filing date: 1959-11-16
Publication date: 1962-03-06
Anticipated expiration: 1979-03-06

Description

March 6, 1962 J. w. JACOBS REFRIGERATING APPARATUS Filed NOV. 16, 1959 ll Fig 1.;

IN V EN TOR.

[m w S. w W H 3,023,589 REFRIGERATING APPARATUS James W. Jacobs, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Nov. 16, 1959, Ser. No. 853,084 7 Claims. (Cl. 62-156) This invention relates to refrigerating apparatus and more particularly to a household refrigerator having an improved defrost control system.

It is an object of this invention to provide a defrost control which eliminates the need for a time clock or the like for periodically initiating the defrost cycle.

More particularly, it is an object of this invention to provide a refrigerating system which is so designed that changes in the temperature of an accumulator located at the outlet of the evaporator can be utilized for initiating a defrost cycle.

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 embodiment of the present invention is clearly shown.

In the drawing:

FIGURE 1 schematically shows a household refrigerator embodying my invention.

FIGURE 2 is a schematic view of the refrigerant circuit shown in FIGURE 1.

FIGURE 3 shows a circuit diagram for the electrical controls.

Referring now to the drawing wherein a preferred embodiment of the invention has been shown, reference numeral 5 designates the cabinet of a household refrigerator having anabove freezing temperature food storage compartment 6, at below freezing food storage compartment 7, a machinery compartment 8, and an evaporator compartment 9. I

The refrigerating system includes a conventional sealed motor compressor unit which is adapted to compress the refrigerant vapor and to discharge the compressed vapor into a condenser 12 wherein the refrigerant is converted into a liquid before entering a capillary tube restrictor 14. The outlet of the capillary tube 14 is connected to an evaporator 16 which serves to cool the air for the compartments 6 and 7 in a manner to be explained more fully hereinafter.

The design of the refrigerating system and the quantity of refrigerant placed in the system is such that during normal operating conditions, all of the liquid refrigerant becomes vaporized in the evaporator 16 before returning to the compressor 10. It has been found that an excessive accumulation of frost on the evaporator 16 causes its heat absorbing characteristics to be altered so that it operates at a lower temperature than normal. When the evaporator temperature is thus lowered, the quantity of liquid refrigerant in the evaporator increases to a point where some of the liquid refrigerant spills over into the accumulator 18 located at the outlet of the evaporator. When this takes place, the temperature of the accumulator 18 drops in temperature and this drop in temperature is used to initiate a defrost cycle.

Under normal operating conditions the compressor 10 is cycled by means of a thermostat assembly 26 which includes a temperature sensing bulb 22 arranged in thermal exchange relationship with the evaporator 16. This thermostat assembly is adapted to close the switch 32 so as to energize the compressor 10 whenever the temperature of the evaporator 16 exceeds a temperature of 12 F. and is adapted to open the switch 32 so as to deenergize the 3,923,589 Patented Mar. 6, 1962 compressor 10 whenever the temperature of the evaporator 16 falls below 6 F.

A defrost control thermostat assembly 24, which includes a temperature sensing bulb 26 is arranged to sense the temperature of the accumulator 18. The thermostat assembly serves to actuate the switch 28 so as to deenergize the compressor 10 when the temperature of the accumulator drops below 6 F. At this temperature, the switch 28 moves from its full line position, shown in FIGURE 3, to the dotted line position, in which latter position a circuit is closed to an electric heater 30 arranged in thermal exchange relationship with the evaporator 16 so as to cause defrosting of the evaporator. The switch 28 remains in its dotted line position until the temperature of the accumulator 18 reaches 50 F., at which time, the circuit to the electric heater is opened by the switch 28 and the circuit to the motor compressor unit 10 is reestablished.

Reference numeral '40 designates an electric motor which serves to operate a condenser fan 42 and an evaporater fan or blower 44. As indicated in FIGURE 3 of the drawing, the motor 40 is connected in parallel with the compressor motor 10 so as to operate in unison with the compressor 10.

As indicated in FIGURE 1 of the drawing, the evaporator 16 serves to refrigerate air for both the frozen food storage compartment 7 and the above freezing food storage'compartment 6. The quantity of air circulated and the temperature of the air leaving the evaporator 16 is suflicient to maintain the contents of the frozen food storage compartment 7 free of frost at all times. Any frost which might form momentarily in the food storage compartment is removed by the process of sublimation in accordance with well known principles.

Whenever the compressor 16] is deenergized either by virtue of opening of the switch 28 or switch 32, the fan 44 will stop operation so as to avoid circulation of warm air through the frozen food compartment 7.

For purposes of illustration there is shown a cabinet in which the refrigerated air is circulated upwardly from the evaporator compartment 9 through an air duct located adjacent the rear of the compartments 6 and 7 and a corresponding amount of air is returned to the inlet of the evaporator blower 44 through the return air duct Which is provided with

return air inlets

64 and 66 which for purposes of illustration have been shown as located in the sidewalls of the compartments 6 and 7, respectively.

The temperature of the compartment 6 can be closely ,regulated by means of a damper 52, which is arranged at the outlet of the refrigreated air supply duct, as shown. This damper is controlled in response to changes in temperature of the thermostatic bulb 54 located in the compartment 6 through the action of the damper actuator bellows 56. The thermostat 54 is preferably designed to maintain the temperature in the compartment 6 approximately between 35 F. and 40 F. The quantity of air and the temperature of the air admitted into the frozen food compartment 7 is preferably such that the temperature in this latter compartment is maintained between approximately 5 F. and +5 F. The temperature values given herein are given for purposes of illustration and may be varied to suit specific requirements.

While the embodiment of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. In a refrigerator, the combination, a cabinet having a pair of refrigerated food storage compartments, a refrigeration system for cooling said compartments, said refrigerating system comprising an evaporator, a compressor, a condenser, and refrigerant flow connections between said evaporator, compressor and condenser, said refrigerant flow connections including an accumulator at the outlet of said evaporator, circuit means controlling the operation of said compressor, a blower circulating air for at least one of said compartments in thermal exchange relationship with said evaporator, said circuit means including a first thermostatically operated switch means re- SpOnsiVe to refrigeration requirements for starting and stopping said compressor, a second thermostatically operated switch means responsive to the temperature of said accumulator for deenergizing said compressor in response to a predetermined decrease in temperature of said accumulator, means for defrosting said evaporator, said second thermostatically operated switch means including means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said accumulator.

2. In a refrigerator, the combination; a cabinet having a refrigerated food storage compartment; a refrigeration system comprising an evaporator, a compressor, a condenser, and refrigerant flow connections between said evaporator, compressor and condenser; and refrigerant flow connections including an accumulator at the outlet of said evaporator; circuit means controlling the operation of said compressor; said circuit means including a first thermostatically operated switch means responsive to refrigeration requirements for starting and stopping said compressor and a second thermostatically operated switch means responsive to the temperature of said accumulator for deenergizing said compressor in response to a predetermined decrease in temperature of said accumulator; and means for defrosting said evaporator; said second thermostatically operated switch means including means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said accumulator and for reenergizing said compressor in response to a predetermined increase in temperature of said accumulator.

' 3. In combination; a cabinet having a pair of refrigerated food storage compartments, an evaporator compartment and a condensing compartment; a refrigeration system comprising an evaporator in said evaporator dompartment, a compressor and a condenser in said condensing compartment, and refrigerant flow connections between said evaporator, compressor, and condensor; said refrigerant flow connections including an accumulator at the outlet of said evaporator; a blower for circulating air to be refrigerated in thermal exchange relationship with said evaporator; circuit means for controlling the operation of said compressor and said blower; said circuit means including a first thermostatically operated switch means responsive to refrigeration requirements for starting and stopping said compressor and said blower and a second thermostatically operated switch means responsive to the temperature of said accumulator for deenergizing said compressor in response to a predetermined decrease in temperature of said accumulator; means for defrosting said evaporator; said second thermostatically operated means including means for initiating operation of said de frosting means in response to a predetermined decrease in temperature of said accumulator.

4. In combination; a cabinet having a pair of refrigerated food storage compartments, an evaporator compartment and a condensing compartment; a refrigeration system comprising an evaporator in said evaporator compartment, a compressor and a condenser in said condensing compartment, and refrigerant flow connections between said evaporator, compressor, and condenser; said refrigerant flow connections including an accumulator at the outlet of said evaporator; means including a blower for circulating air in thermal exchange relationship with said evaporator and for discharging said air into said food storage compartments; circuit means for controlling the operation of said compressor and said blower; said circuit means including a first thermostatically operated switch means responsive to refrigeration requirements for starting and stopping said compressor and said blower and a second thermostatically operated switch means responsive to the temperature of said accumulator for deener'gizing said compressor in response to a predetermined decrease in temperature of said accumulator; means for defrosting said evaporator; said second thermostatically operated means including means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said accumulator; damper means for varying the ratio of air circulated by said blower to each of said compartments.

5. In combination; a cabinet having a pair of refrigerated food storage compartments, an evaporator compartment and a condensing compartment; a refrigeration system comprising an evaporator in said evaporator compartment, a compressor and a condenser in said condensing compartment, and refrigerant flow connections between said evaporator, compressor, and condenser; said refrigerant flow connections including an accumulator at the outlet of said evaporator; means including a blower for circulating air in thermal exchange relations-hip with said evaporator and for discharging said air into said food storage compartments; circuit means for controlling the operation of said compressor and said blower; said circuit means including a first thermostatically operated switch means responsive to refrigeration requirements for starting and stopping said compressor and said blower and a second thermostatically operated switch means responsive to the temperature of said accumulator for deenergizing said compressor in response to a predetermined decrease in temperature of said accumulator; means for defrosting said evaporator; said second thermostatically operated means included'means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said accumulator; damper means for varying the ratio of air circulated by said blower to each of said compartments; and a thermostat responsive to the temperature in one of said compartments controlling said damper means.

6. In a refrigerator, the combination, a cabinet having a pair of refrigerated food storage compartments, a refrigeration system for cooling said compartments, said refrigerating system comprising an evaporator, a compressor, a condenser, and refrigerant flow connections between said evaporator, compressor and condenser, said refrigerant flow connections including a conduit leading from the outlet of said evaporator to said compressor, circuit means controlling the operation of said compressor, a blower circulating air for at least one of said compartments in thermal exchange relationship with said evaporator, said circuit means including a first thermostatically operated switch means responsive to the temperature produced by said evaporator for starting and stopping said compressor, a second thermostatically operated switch means responsive to the temperature of said conduit for deenergizing said compressor in response to a predetermined decrease in temperature of said conduit, means for defrosting said evaporator, said second thermostatically operated switch means including means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said conduit.

7. In a refrigerator, the combination; a cabinet having a refrigerated food storage compartment; a refrigeration system comprising an evaporator, a compressor, a condenser, and refrigerant flow connections between said evaporator, compressor and condenser; said refrigerant flow connections including an accumulator at the outlet of said evaporator; circuit means controlling the operation of said compressor; said circuit means including a first thermostatically operated switch means responsive to refrigeration requirements for starting and stopping said compressor and a second thermostatically operated switch means responsive to the temperature of said accumulator for deenergizing said compressor in response to a predetermined decrease in temperature of said accumulator; and means energized by said second thermostat for defrosting said evaporator; said second thermostatically operated switch means including means for initiating operation of said defrosting means in response to a predetermined decrease in temperature of said accumulator.

References Cited in the file of this patent UNITED STATES PATENTS McCloy May 6, 1952 R-aney Aug. 31, 1954 Murphy et a1. May 21, 1957 Slattery Aug. 12, 1958 Wurtz Dec. 9, 1958 Mann Oct. 6, 1959 Mann Nov. 17, 1959