US3248893A - Refrigeration apparatus - Google Patents

Description

May 3, 1966 J. A. M LEAN REFRIGERATION APPARATUS 2 Sheets-Sheet 1 Filed Feb. 8. 1965 FIG.|.

INVENTOR John A. Mc Lean ATTORNEY y 3, 1966 J. A. M LEAN 3,248,893

REFRIGERATION APPARATUS Filed Feb. 8. 1965 2 Sheets-Sheet 2 45 I8 4 H32 C A O Q in 29 2a f I FIG.2.

United States Patent 3,248,893 REFRIGERATION APPARATUS John A. McLean, Upper Arlington, Columbus, Ohio, assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed Feb. 8, 1965, Ser. No. 431,023 4 Claims. (Cl. 62-156) This invention relates to refrigeration systems, and more particularly to single evaporator refrigerator systems for use in domestic refrigerator-freezer cabinets.

Recently, the trend in refrigerator design has been to producing a refrigerator-freezer cabinet in which the appearance of frost is eliminated from both the fresh food compartment and the freezer compartment. Generally, this is accomplished by the circulation of air over an evaporator positioned outside of the compartments with the frost collecting on the evaporator and with the cooled air from the evaporator passed through the various compartments. Frost is removed from the evaporator by any of several well known methods, including the introduction of warm refrigerant into the evaporator or by applying external heat to the evaporator through the use of electrical resistance heaters, or by a combination of these or other means.

In such refrigeration systems there is an energy input to the system to cool the various compartments and an additional energy input to the system to heat the evaporator for defrost purposes. In other words, the system must be capable of producing both a cooling cycle to provide heat exchange in the various compartments for cooling and a heating cycle to provide heat exchange at the evaporator for elimination of frost thereon.

Such prior systems as just discussed, wherein heat is removed from the apparatus by refrigerating means and then heat is supplied to the apparatus to remove the frost which has accumulated on the evaporator, are uneconomical both with respect to operation and manufacture.

The present invention has as an object to provide a multiple level refrigerating system of the single evaporator type in which a heating cycle is eliminated.

A further object of the invention is to improve a refrigerating system for a domestic refrigerator-freezer wherein, when the refrigerating apparatus is operating, that is, the compressor is energized and refrigerant is supplied to the evaporator, air is passed over the evapo rator and then directed through a below-freezing compartment and continuously returned to the evaporator region until such time as the temperature in the belowfreezing compartment has reached the desired level. Thereafter, with the compressor shut down, air from the above-freezing compartment is continuously circulated over the evaporator and thence back to the above-freezing compartment until the frost which has accumulated on the evaporator during operation of the refrigerating cycle and the first portion of compressor off period has been melted. Thus, during this melting or defrosting portion of the cycle the necessary features and results are obtained without operation of the refrigerating system but merely by the circulation of air thereover. Inasmuch as this circulated air utilized to defrost the evaporator is taken from the above-freezing compartment, no external source of heat need be added to melt the frost from the evaporator and the refrigeration system need not be operated in order to suitably cool the above-freezing compartment, under normal operating conditions, since the air circulated from the above-freezing compartment, over the evaporator and back to the above-freezing compartment gives up heat as it passes over the evaporator to melt the frost thereon and consequently the temperature in the above-freezing compartment is correspondingly lowered.

3,248,893 Patented May 3, 1966 This novel operation is effected by a domestic refrigerator-freezer having a freezer compartment, a fresh food compartment and a third compartment in which is located a single evaporator for refrigerating both the freezer compartment and the fresh food compartment.

The evaporator compartment is provided with an inlet thereto from the freezer compartment and an outlet therefrom to the freezer compartment and similarly is provided with an inlet thereto from the above-freezing compartment and an outlet therefrom to the above-freezing compartment. There is also disclosed a damper construction and means for adjusting the damper so that, when the compressor is operating and the evaporator is chilled so that air flowing thereover is refrigerated, the first two mentioned openings are open for flow of air from the freezer compartment to the evaporator compartment, in heat exchange relation with the evaporator, and back to the freezer compartment in a continuous flow, thereby cooling the refrigerator compartment. At the same time, the openings to and from the above-freezing compartment are maintained closed by their dampers until such time as the control mechanism provided therefor shuts off the compressor, whereupon the positions of the four dampers are reversed for shutting off the flow of air between the freezer compartment and the evaporator compartment and establishing flow of air between the above-freezing compartment and the evaporator compartment.

During this portion of the cycle, which is referred to as a defrost portion, relatively warm air from the abovefreezing compartment flows in heat exchange relation with respect to the evaporator to melt from the latter any frost or ice which has accumulated during its last operating cycle. Not only does the relatively warm air from the above-freezing compartment melt any accumulated frost from the evaporator, but also such air is chilled and moisture is removed due to its contact with the evaporator and the frost thereon with the result that the temperature and moisture within the above-freezing compartment is lowered to a desirable level.

An object of the invention is to provide, in a refrigerator-freezer having a freezer compartment and an above-freezing compartment, a refrigerating system for said compartments, in which a single evaporator provides cooling for both compartments and the refrigerating system is in operation only while the freezer compartment is being refrigerated but is not in operation for refrigeration of the above-freezing compartment.

Another object of the invention is to eliminate any necessity for adding external heat during a warming cycle in a refrigeration system for a refrigerator-freezer in order to melt frost or ice collecting on an evaporator in that system.

Another object of the invention is to provide, in refrigerator-freezer apparatus, a refrigeration system in which air from the above-freezing compartment is circulated over an evaporator which serves both the abovefreezing compartment and the freezer compartment, to remove frost and ice collected thereon and to continuously return such air from the evaporator back to the above-freezing compartment to cool the latter as well as to melt the frost collected on the evaporator.

These and other objects, features and advantages of the invention will appear more fully from the following detailed description, taken in connection with the accompanying drawings forming a part of the application, in which:

' FIGURE 1 is a rear elevational view, partially in section, of a refrigerator-freezer cabinet having the invention employed therein and showing air fiow through the compartment;

I on an enlarged scale to show the invention in greater detail; and

FIG. 3 is an elevational view of a portion of the structure of FIG. 2, taken on an enlarged scale showing that portion of the structure in greater detail.

Referring to the drawings, especially FIGS. 1 and 2, there is shown a refrigerator-freezer cabinet having walls defining a top positioned freezer compartment 11 and a bottom positioned above-freezing compartment 12, these two compartments being sometimes referred to as a below-freezing temperature compartment 11 and an above-freezing temperature compartment 12. Between the freezer compartment 11 and the above-freezing compartment 12, and preferably adjacent the rear of the cabinet 10, there is positioned an evaporator compartment 13 containing a refrigerant evaporator 14. The refrigerant evaporator 14 may be of the finned tube type and is connected into a refrigerating system of the compressor-condenser-evaporator type. The refrigerating system is not shown in its entirety and may be of any type well known in the art, and the details are not shown since they form no part of the present invention.

The evaporator compartment 13 is provided with a pair of outlet openings 16 and 17 at one side thereof communicating with the freezer compartment 11 and the above-freezing compartment 12, respectively. At the opposite side of the evaporator compartment 13 there is provided a pair of inlet openings 18 and 19, likewise communicating with the freezer compartment 11 and the above-freezing compartment 12, respectively.

Flow control means in the form of a damper 21 supported at a hinge 22, and a damper 23 supported at a hinge 24, are provided at the outlet side of the evaporator compartment 13 for closing the outlet openings 16 and 17, respectively. At the inlet side of the evaporator compartment 13 a damper 26, supported at a hinge 27, and a damper 28, supported at a hinge 29, are disposed for closing the inlet openings 18 and 19, respectively. A tie rod 31 is pivotally connected at one end thereof to the damper 21, and the other end to the damper 23, as best shown in FIG. 2. In like manner, the damper 26 is pivotally connected to one end of a tie rod 32 and the opposite end of the rod is pivotally connected to the damper 28.

Referring to FIG. 2, it will be observed that the tie rods 31 and 32 are each attached to opposite ends of a connecting link 33 having a bushing 34 slidably supported between springs 36 and 37 on a push-pull rod 38. The springs 36 and 37 are held captive between a pair of disks 39 and 41 located on the push-pull rod 38, and the lower end of the rod is rotatably connected to a crank 42. The crank 42 is directly engaged on a drive shaft 43 of a damper drive motor 44.

The evaporator compartment 13 is provided with air translating means in the form of an electric fan 46 disposed in the inlet side of the compartment. The linkage means described in the previous paragraphs provides mechanism for maintaining the damper 21 and the damper 26 in the closed position when the dampers 28 and 23 are in the open position, and for maintaining the dampers 23 and 28 in their closed positions when the dampers 21 and 26 are in the open position.

With the dampers 23 and 28 in the open position, as shown in FIG. 2, and the blower operating, air is circulated from the evaporator compartment 13 through the outlet 17 into the above-freezing compartment 12 and returned through the inlet 19 to the evaporator compartment.

When the crank 42 is rotated through an arc of 180, the dampers 26 and 21 are moved to open positions and the dampers 23 and 28 are moved to closed positions. The flow of air, as shown by the dot-dash lines in FIG. 2, then passes from the evaporator compartment 13 through the outlet 16 into the freezer compartment 11 and returns through the inlet 18 to the evaporator compartment.

In the system shown, it is desirable that the dampers 21 and 26 or 23 and 28 be firmly held in place when in the closed position to prevent leakage of air into the compartment 11 or 12, whichever is closed from the evaporator compartment 13. The linkage, as disclosed, provides for movement of the connecting rod 33 by exerting force through either the spring 36 or the spring 37, thereby permitting the crank 42 to rotate the full 180 when the dampers have come to a closed position prior to the full crank rotation. The compression of the springs provides additional force on the rod 33 after one damper closes, thus insuring seating of both dampers.

In addition, the linkage disclosed permits use of a motor 44 which may be a very small geared motor similar to a clock motor, which is unidirectional with no clutch or gear shift device.

FIG. 2 includes a schematic wiring diagram for the refrigeration system herein disclosed and includes a temperature sensing element in the form of a control bulb 59 positioned in the evaporator compartment 13 in the path of outlet air flowing therefrom. The control bulb 59 is connected to a thermostatic element 61 controlling a single throw switch 62 in the circuit. The circuit furnishes power to a motor compressor 67 forming a part of the refrigeration system, and to the damper drive motor 44. The wire connecting the motor 44 in the circuit is also connected to a snap action single pole double throw switch 68 which is actuated by a cam 69 carried by the drive shaft 43 of the damper drive motor. The snap acting switch 68 is biased toward the cam surface to snap one way into engagement with contact 72 as the rise on the cam engages it and 180 later to snap the other way into engagement with contact 73 as it falls off the rise of the cam and rides along the flat side of the latter.

The electric fan or blower 46 is connected into the circuit through a loop which includes a single pole switch 71 which remains closed when the refrigerator door is in the closed position and is biased open when the refrigerator door is in open position. Both the major refrigeration circuit loop and the loop containing the blower or fan 46 are connected across a pair of supply lines L1 and L2, which may be any standard volt house current outlet or the equivalent.

The apparatus and circuitry hereinabove described operates in the following manner. With the switch 71 closed and the dampers 21 and 26 closing the openings 16 and 18 to the freezer compartment 11, air is circulated from the above-freezing compartment 12 through the inlet 19 into the evaporator compartment 13 Where it flows over the chilled and usually frosted evaporator and discharges through the opening 17 back to the above-freezing compartment. Due to the air being drawn across the evaporator 14, and thereby chilled, switch 62, which is set to close at a relatively high temperature, is maintained in an open position and the compressor 67 does not operate. The air leaving the evaporator is gradually warming due to the shutdown of the compressor 67 and the melting of any frost formed on the evaporator. The water resulting from melting of frost or ice on the evaporator may be carried from the evaporator compartment to a point of disposal by any suitable means (not shown).

The temperature sensing bulb 59 and the thermostat 61 are so calibrated that when a temperature in the range of from 35 F. to 40 F. is sensed by the bulb, the switch 62 is moved to closed position. Closing of the switch places a line potential across the compressor motor 67 and the damper motor 44, thereby initiating operation of both of these electrical devices. The damper motor 44 operates through a turn of the shaft 43, thereby moving the dampers to a reverse position from that previously occupied so that the openings 16 and 18 are opened and the openings 17 and 19 are closed. At the end of the 180 turn of the shaft 43, the switch 68 will be move from the high side of the cam 69 to the low side thereof and consequently the switch moves from the contact 72 to the contact 73.

The compressor 67 continues to operate and to lower the temperature of the evaporator 14, while the blower 46 circulates chilled air through the freezer compartment 11 from the evaporator 13, thereby cooling the freezer compartment. During this cycle frost may form on the evaporator 14. However, when the temperature sensed by the bulb 59 drops to within the range of F. to F., the thermostat 61 actuates the switch 62 to the open position. With the switch 62 in the open position a line potential is established across the damper motor 44 and the shaft 43 again turns 180, moving the switch 68 from the contact 73 to the contact 72, and correspondingly reversing the positions of the dampers to close off the freezer compartment 11 from the evaporator compartment 13 and establish communication between the above-freezing compartment 12 and the evaporator compartment. With the switch 68 connected to the contact 72 and the switch 62 open, the compressor 67 is shut off and the defrost cycle (with which this description of operation started) again begins, during which the above-freezing compartment is cooled and the evaporator deiced or defrosted.

While the invention has been shown in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications without departing from the spirit thereof.

I claim as my invention:

1. In apparatus having a freezing compartment and an above-freezing compartment, a refrigeration system for said compartments including a compressor, a condenser and an evaporator, means defining a compartment for said evaporator, said evaporator compartment having an inlet thereto from the freezer compartment and an outlet therefrom to said freezer compartment, and having an inlet thereto from the above-freezing compartment and an outlet therefrom to said above-freezing compartment, damper means for controlling flow of air through said evaporator compartment inlet and outlet, control means for adjusting said damper means from a first position wherein the inlet and outlet communicating with the freezer compartment are open and the inlet and outlet communication with the above-freezing compartment are closed to a second position wherein the inlet and outlet communicating with the freezer compartment are closed and the inlet and outlet communicating with the abovefreezing compartment are open, said control means providing for operation of the compressor to chill the evaporator when the damper means is in said first position and preventing operation of the compressor when said damper means is in said second position.

2. In apparatus having a freezing compartment and an above-freezing compartment, means for refrigerating said compartments including a compressor and an evaporator, means defining a compartment for said evaporator, said evaporator compartment having a pair of air inlets and a pair of air outlets, one of said outlets and one of said inlets providing for flow of air between the evaporator compartment and the freezer compartment, the other of said inlets and the other of said outlets providing for flow of air between the evaporator compartment and the abovefreezing compartment, closure means for said inlets and outlets, and control means for said closure means and the compressor, said control means providing for adjustment of the closure means to a first position wherein air flows from the freezer compartment to the evaporator compartment, in heat exchange relation to the evaporator, and back to the freezer compartment and a second position wherein air flows from the above-freezing compartment to the evaporator compartment, in heat exchange relation to the evaporator, and back to the above-freezing compartment, said control means also providing for operation of the compressor while said closure means is in said first position and shut off of compressor while said means is in said second position.

3. Structure as specified in claim 1, wherein the evaporator compartment is disposed between the freezer compartment and the above-freezing compartment.

4. Structure as specified in claim 2, wherein the evaporator compartment is located between the freezer compartment and the above-freezing compartment.

References Cited by the Examiner UNITED STATES PATENTS 3,107,501 10/1963 Stickel 62156 3,126,716 3/1964 De Witte 62-187 3,164,970 1/1965 Hubacker 62156 3,174,297 3/1965 Kuhn 62156 WILLIAM J. WYE, Primary Examiner.

Claims (1)

1. IN APPARATUS HAVING A FREEZING COMPARTMENT AND AN ABOVE-FREEZING COMPARTMENT, A REFRIGERATION SYSTEM FOR SAID COMPARTMENTS INCLUDING A COMPRESSOR, A CONDENSER AND AN EVAPORATOR, MEANS DEFINNG A COMPARTMENT FOR SAID EVAPORATOR, SAID EVAPORATOR COMPARTMENT HAVING AN INLET THERETO FROM THE FREEZER COMPARTMENT AND AN OUTLET THEREFROM TO SAID FREEZER COMPARTMENT, AND HAVING AN INLET THERETO FROM THE ABOVE-FREEZING COMPARTMENT AND AN OUTLET THEREFROM THE SAID ABOVE-FREEZING COMPARTMENT, DAMPER MEANS FOR CONTROLLING FLOW OF AIR THROUGH SAID EVAPORATOR COMPARTMENT INLET AND OUTLET, CONTROL MEANS FOR ADJUSTING SAID DAMPER MEANS FROM A FIRST POSITION WHEREIN THE INLET AND OUTLET COMMUNICATING WITH THE FREEZER COMPARTMENT ARE OPEN AND THE INLET AND OUTLET COMMUNICATION WITH THE ABOVE-FREEZING COMPARTMENT ARE CLOSED TO A SECOND POSITION WHEREIN THE INLET AND OUTLET COMMUNICATING WITH THE FREEZER COMPARTMENT ARE CLOSED AND THE INLET AND OUTLET COMMUNICATING WITH THE ABOVEFREEZING COMPARTMENT ARE OPEN, SAID CONTROL MEANS PRO-

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