US2997857A

US2997857A - Refrigerating apparatus

Info

Publication number: US2997857A
Application number: US759065A
Authority: US
Inventors: Harry F Clark
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1958-09-04
Filing date: 1958-09-04
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29

Description

1961 H. F. CLARK 2,997,857

REFRIGERATING APPARATUS Filed Sept. 4, 1958 2 Sheets-Sheet 1 56 I l 58 4 I f 61 77 I 1 2O Fig.

INVENTOR. H arry F. Olaf/r His Aflorn ey 1961 H. F. CLARK 2,997,857

REFRIGERATING APPARATUS Filed Sept. 4, 1958 2 Sheets-Sheet 2 -96 INVENTOR.

Harry F. Clark Fig. 3 BY 544M60- His Al/ome United States Patent tors Corporation, Detroit, Mich., a corporation of Delaware Filed Sept. 4, 1958, Ser. No. 759,065 6 Claims. (Cl. 62-208) This invention pertains to refrigerating apparatus and especially to forced air refrigerators with a combined circulation system for two compartments.

The advantages of forced air refrigeration for both the below and above-freezing compartments of household refrigerators are now beginning to be appreciated. To keep the cost low enough for mass consumption, it is essential that the system be reduced to its simplest and most inexpensive form.

It is an object of this invention to provide a forced air refrigerator having a single fan and combined air circulating system for two compartments with a simple, inexpensive, reliable control system which will insure the maintenance of satisfactory refrigerating temperatures in each compartment.

It is another object of this invention to provide a forced air refrigerator having a single fan and combined air circulating system for two compartments with a simple, inexpensive, reliable duct and control system in which the refrigeration system will operate whenever either compartment requires refrigeration and one of the compartments will not be cooled below a preselected temperature.

These and other objects are attained in the form shown in the drawings in which an above-freezing compartment is located above the below-freezing compartment. A single evaporator is provided directly beneath the bottom of the below-freezing compartment in heat transfer relation with the bottom wall which may support ice trays and frozen foods. A single blower draws air from the front of both compartments through a ductwork and through the single evaporator and discharges the cooled air through the ductwork to the upper rear of the belowand above-freezing compartments. A damper is provided in the duct leading to the above-freezing compartment so as to shut off the cold air flow whenever the temperature of the above-freezing compartment reaches a predetermined minimum.

To accomplish this, the damper is provided with a bimetallic operator heated by an electric heater connected in series with a first thermostatic switch responsive to the temperature of the above-freezing compartment for controlling the connection with one supply conductor. A double-throw thermostatic switch responsive to the temperature in the below-freezing compartment in the low temperature position connects with the first thermostatic switch and in its high temperature position connects with a shunt which shunts both the heater for the damper and the first thermostatic switch responsive to the abovefreezing compartment temperature. The double-throw switch element is connected to the motor-compressor unit for the single evaporator and the blower motor which are in parallel with each other.

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 embodiment of the present invention is clearly shown.

In the drawings:

FIGURE 1 is adiagrammatic representation of a refrigerator including the control system and Wiring diagram embodying one form of my invention;

FIGURE 2 is an enlarged sectional view of the damper and its operating means;

FIGURE 3 is a simplified wiring diagram of the circuit shown in FIGURE 1; and

FIGURE 4 is a sectional view of a modified damper and operating means.

Referring ,now to the drawings and more particularly to FIG. 1, there is illustrated by dot-dash lines a household refrigerator cabinet 20 having insulated walls enclosing an upper above-freezing compartment 22 and a lower below-freezing compartment 24 which are separated by an insulated wall 26. The compartments are closed by a single insulated door 28. Beneath the belowfreezing compartment, in thermal contact with its bottom wall 29 and the ice tray 31 thereon is a single vertical fin evaporator 30 positioned in the horizontal duct 32 provided beneath the bottom wall thereof. A duct 34 extends from the front portion of the above-freezing compartment 22 downwardly and has an entrance 36 connecting with the below-freezing compartment 24 extending to the front of the horizontal duct 32 in front of the evaporator 39. At the rear of the duct 32 is the entrance to a centrifugal fan 38 driven by an electric motor 40. This centrifugal fan 38 discharges upwardly through a duct 42 in the rear wall having a discharge outlet 44 into the upper rear of the belowfreezing compartment 24. This duct 42 also has an upwardly extending extension 9 provided with the damper 1. This extension 9 extends up to an outlet 46 provided in the upper rear of the abovefreezing compartment 22.

It is desired to provide a control system arranged so that when the above-freezing compartment requires refrigeration and the below-freezing compartment does not, the refrigerating unit will start and the damper will open. When the above-freezing compartment does not require refrigeration and the freezing compartment does require refrigeration, the damper must close and the refrigeration unit must operate. The above-freezing compartment must be provided with refrigeration whenever it is required by its temperature conditions and the belowfreezing compartment will be cooled whenever the abovefreezing compartment receives refrigeration and also when it alone requires refrigeration.

The single evaporator 30 is supplied with refrigeration from a sealed motor-compressor unit 48 which withdraws evaporated refrigerant from the evaporator 30 through the suction conduit 50 and forwards compressed refrigerant to a condenser 52 which delivers the liquefied refrigerant to a flow restricting capillary tube 54 to the front portion of the evaporator 30. A singlepole thermostat 56, preferably of the snap-acting type, is shown as provided with a thermostat bulb 58 located in the upper part of the above-freezing compartment 22 to close the switch 60 whenever the temperature of the compartment 22 is above a selected temperature and requires refrigeration, and to open the switch 60 whenever the refrigerating requirements of the compartment 22 are satisfied. This switch 60 has one terminal connected to the supply conductor 62. This switch may be of the type shown in the Pearce Patent 2,229,612, issued January 21, 1941, or the Grooms Patent 2,351,038, issued Iune 13, 1944.

The second terminal of this switch 60 is connected by the conductor 64 to the terminal 7 of the control 4 for the damper. The second terminal for the control 4- is connected by the conductor 66 to the second supply conductor 9a. A branch conductor '67 extends from the conductor 64 to the low temperature terminal 70 of the double-throw snap-acting thermostatic switch "68. This switch 68 has a double-throw element 72 provided with a toggle snap action spring 74 for holding it in connection with either the low temperature contact 70' or a high temperature contact 76. The high temperature contact 76 is connected by a conductor 77 directly to ductor 84 and a branch conductor 86 to one terminal of the fan motor 40. The second terminal of fan motor 40 is connected by a conductor 88 to the second supply conductor 90. The conductor 84 connects through a second branch conductor 92 to a starting relay 94 providing a connection during the starting period with the phase winding 96 and having a series coil connected with the main winding 98 of the electric motor 121 in the sealed motor-compressor unit 48. The second terminal of the sealed motor-compressor unit is connected by the conductor 123 with the second supply conductor 90.

In operation, should the freezing compartment 24 require refrigeration, the thermostat bulb 82 will become warm and the bellows 78 will expand sufficiently to move the double-throw elements 72 into engagement with the high temperature contact 76. This will directly energize the fan motor 40 and the motor-compressor unit 48. Operation of both will continue until the refrigeration demand is satisfied and the bulb S2 cools and the bellows 78 contracts sufliciently to move the doublethrow contact 72 back to the low temperature contact 70. During this operation, the damper 1 will remain closed as long as the switch 60 is open and the heater 6 is deenergized. The above-freezing compartment 22 will not receive any substantial amount of refrigeration. This will prevent the above-freezing compartment 22 from becoming too cool.

Should the above-freezing compartment 22 require refrigeration, the thermostat bulb 58 will become warm, causing the expansion of the bellows 56 and the closing of the switch 60. This will energize the series heater 6 to heat the bimetal 2 causing the slow openings of the damper 1. The closing of the switch 60 also will complete a circuit through the

conductors

64, 66, 84, 86, 92, the fan motor 40 and the motor-compressor unit 48. This operation will cause the evaporator to be refrigerated coincidentally with the operation of the motorcompressor unit 48 and circulation to take place from the fan 38 through the duct 42 and the duct 9 through the

outlets

44 and 46 in parallel through the

compartments

24 and 22 to the return duct 34. This operation will continue until the demand for refrigeration in the above-freezing compartment 22 is satisfied and the bulb 58 is cooled sufiiciently to contract the bellows 56 and open the switch 60 reclosing the damper 1.

The freezing compartment 24, therefore, will receive refrigeration whenever its temperature is sufliciently high to require it, as ascertained by the temperature of the bulb 82, and it will also receive a lesser amount of refrigeration when the above-freezing compartment 22 requires refrigeration, as ascertained by the temperature of the bulb 58. The above-freezing compartment cannot be cooled below the temperature at which the bulb 58 opens the switch 60 while the freezing compartment cannot be denied refrigeration whenever the bulb 82 reaches a predetermined high temperature. If desired, bimetal switches located in the

compartments

22 and 24 may be substituted for the bulb and bellows operated

switches

60 and 68.

A simplified type of damper and operating mechanism is shown in FIG. 2. Preferably, this portion of the duct 9 is substantially rectangular in cross-section. The damper 1 extends only at a relatively slight angle in the closed position to reduce the angle between the closed and open position. The duct 9 is provided with bulges 127 adjacent the upper and lower ends of the damper 1 to form seats for the engagement of the damper in the closed position to insure relatively good sealing. The damper 1 is provided with a pivoting shaft 129 extending at its opposite ends through the sidewalls of the duct 9 and provided at the far end with a crank 3 connecting with a nylon push plate 131 beyond the far side of the duct 9, as viewed in FIG. 2. The nylon push plate extends to the left and is riveted to the upper end of a folded bimetal 2. The other end of this bimetal 2 is riveted by two rivets to the adjacent wall of the duct 9.

The heater 6 is supported within the bimetal 2. The heater 6 is connected by the conductor 135 through a stationary contact 137 and a movable switch contact 5 and a conductor terminal 7 with the conductor 64. The movable switch contact 5 is supported by a C-shaped spring support 139 normally keeping it in the closed position contacting the stationary contact 137. The movable contact 5 is connected to a hook-type operating member 133. When the heater 6 heats the bimetal 2 sufficiently to move the upper portion of the bimetal 2 and the nylon push plate 131 to the right sufliciently to move the damper 1 to its vertical or fully open position, the bimetal 2 Will engage the hook at the right end of the member 133 to pull the contact 5 away from the contact 137 to deenergize the circuit of the heater 6. This deenergization, however, will only be momentary and actually the contact 5 will reclose and open repeatedly, providing the heater 6 with just suflicient heat to keep the damper 1 in the fully open position.

The contact 5 is connected by the conductor 7 to the conductor 64 while the other terminal of the heater 6 is connected by the conductor 66 to the second supply conductor 90. The duct 9 is provided with louver-type vents 8 providing a continuous circulation of air around the heater 6 and the bimetal 2 whenever the damper is in the open position. The

contacts

5, 137, the bimetal 2, the heater 6, the nylon push plate 131 and the crank 3 are enclosed in a casing 143 of electrical insulating material which is preferably molded to the adjacent portion of the duct 9. The vents 8 insure the closing of the damper 1 within a short time after the heater 6 is deenergized by the opening of the switch 60.

In FIGURE 4 there is shown a simplified form of electrically operated damper 151 for the duct 9. In this form the damper 151 is in the form of a flat plate bonded tangentially to the pivot shaft 153 having its ends extending through the side Walls of the duct 9. A bimetal strip 155 bent somewhat in the form of letter G has one end portion 157 Welded to the adjacent side of the duct 9. It is provided with a wide bend or fold at its lower end and extends upwardly and is provided with a right-angled projection 159 having a reduced extension extending through the aperture 161 in the wall of the duct 9 into engagement with the upper portion of the damper 151. The offset relationship of the damper 151 to its pivot shaft 153 causes it to be held by gravity normally in the closed position, as shown in FIG. 4.

Within the fold of the bimetal strip 155 there is provided an electric heater 163 of ample capacity so that it can be continuously energized at full voltage whenever desired. This makes it possible to eliminate the

switch contacts

5 and 137 in this form. The heater 163 replaces the heater 6. However, the heater 163 takes the same place in the electrical circuit as the heater 6. The bimetal strip 155 and the heater 163 are enclosed in a casing 165 of electrical insulating plastic mounted on the adjacent side of the duct 9. Louver-type vents 169 are provided in the wall of the duct 9, providing an air cooling circulation through the casing 165 to cool the bimetal strip 155 and the heater 163.

When the compartment 22 requires refrigeration and the switch 60 is closed, the heater 163 will be energized to cause the bimetal 155 to bow to the right to move the projection 159 to the right until the damper 151 is substantially vertical. The bimetal 155 is provided with a stop 167 which prevents it from moving the damper 151 beyond the vertical position. When the refrigerating requirements for the compartment 22 are satisfied, the switch 60 will be opened to deenergize the heater 163 which will be cooled by the air flow through the louvers 169 and the casing 165 to allow the bimetal 155 to move back to the position shown in FIG. 4 to allow the damper 151 to assume the closed position shown in FIG. 4. This provides a very simple, economical system, low in manufacturing cost.

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. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and passage means for drawing air from said compartments into heat transfer relation with said evaporating means and returning the air to said compartments, electrically operated damper means associated with said passage means for stopping the circulation between said passage (means and the first compartment when deenergized and opening when energized, first and second power supply conductors, said liquefying means including electrical operating means, a temperature responsive snap acting double throw switch means responsive to the temperature of the second compartment having a double throw switch element connected to one terminal of said electrical operating means and having one relatively stationary contact connected to one terminal of said damper means and having a second relatively stationary contact connected to the first supply conductor, a second temperature responsive switch means responsive to the temperature of the first compartment for connecting said first supply conductor to said one terminal of said damper means, said electrical operating means and said damper means having a second terminal connected to said second supply conductor.

2. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and passage means for drawing air from said compartments into heat transfer relation with said evaporating means and returnmg the air to said compartments, electrically operated damper means associated with said passage means for stopping the circulation between said passage means and the first compartment when deenergized and opening when energized, first and second power supply conductors, said liquefying means including electrical operating means, a temperature responsive snap acting double throw i switch means responsive to the temperature of the second compartment having a double throw switch element connected to one terminal of said electrical operating means and having one relatively stationary contact connected to one terminal of said damper means and having a second relatively stationary contact connected to the first supply conductor, a second temperature responsive switch means responsive to the temperature of the first compartment for connecting said first supply conductor to said one terminal of said damper means, said electrical operating means and said damper means having a second terminal connected to said second supply conductor, said damper means including a damper and a thermal operating means for moving said damper from one position to a second position and an electric heater for heating said thermal operating means.

3. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and passage means for drawing air from said compartments into heat transfer relation with said evaporating means and returning the air to said compartments, electrically operated damper means associated with said passage means for stopping the'circulation between said passage means and the first compartment when deenergized and opening when energized, first and second power supply conductors, said liquefying means including electrical operating means, a temperature responsive snap acting double throw switch means responsive to the temperature of the second compartment having a double throw switch element connected to one terminal of said electrical operating means and having one relatively stationary contact connected to one terminal of said damper means and having a second relatively stationary contact connected to the first supply conductor, a second temperature responsive switch means responsive to the temperature of the first compartment for connecting said first supply conductor to said one terminal of said damper means, said electrical operating means and said damper means having a second terminal connected to said second supply conductor, said damper means including a damper and a thermal operating means for moving said damper from one position to a second position and an electric heater for heating said thermal operating means to move said damper from the first to the second position, and a switch electrically connected in shunt circuit with said heater and mechanically associated with said damper to be opened when said damper is in its second position.

4. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and passage means for drawing air from said compartments into heat transfer relation with said evaporating means and returning the air to said compartments, normally closed damper means associated with said passage means for stopping the circulation between said passage means and said first compartment for controlling the circulation between said passage means and said first compartment, said liquefying means including electrical operating means, electrical supply means, a first temperature responsive means responsive to a high temperature of said second compartment for electrically energizing said electrical operating means from said electrical supply means, a second temperature responsive means responsive to a high temperature of said first compartment for opening said damper means and for electrically energizing said electrical operating means from said electrical supply means in the absence of the energizing of said electrical operating means by said first temperature responsive means.

5. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and pars sage means for drawing air from said compartments into heat transfer relation with said evaporating means and returning the air to said compartments, normally closed damper means associated with said passage means for stopping the circulation between said passage means and said first compartment for controlling the circulation between said passage means and said first compartment, said liquefying means including electrical operating means, electrical supply means, a first temperature responsive means responsive to a high temperature of said second compartment for electrically energizing said electrical operating means from said electrical supply means, a second temperature responsive means responsive to a high temperature of said first compartment for opening said damper means and for electrically energizing said electrical operating means from said electrical supply means in the absence of the energizing of said electrical operating means by said first temperature responsive means, said first and second temperature responsive means being responsive to contemporary low temperatures of both said first and second compartments for preventing the energizing of said electrical operating means.

6. Refrigerating apparatus including means forming first and second compartments, refrigerant liquefying and evaporating means operatively connected, fan and passage means for drawing air from said compartments into heat transfer relation with said evaporating means and returning the air to said compartments, normally closed *7 damper means associated with said passage means for stopping the circulation between said passage means and said first compartment for controlling the circulation between said passage means and said first compartment, said liquefying means including electrical operating means, electrical supply means, a first temperature responsive means responsive to a high temperature of said second compartment for electrically energizing said electrical operating means from said electrical supply means, a second temperature responsive means responsive to a high temperature of said first compartment for opening said damper means and for electrically energizing said electrical operating means from said electrical supply means in the absence of the energizing of said electrical operating means by said first temperature responsive means, said first and second temperature responsive means being responsive to contemporary low temperatures of both said first and second compartments for preventing the energizing of said electrical operating means and the operation of said fan means.

References Cited in the file of this patent UNITED STATES PATENTS 2,251,881 Danielson Aug. 5, 1941 2,863,300 Murphy Dec. 9, 1958 2,866,323 Candor Dec. 30, 1958