Refrigerator Having Cabinet Warming Heat Transfer Device

Many refrigerator cabinet designs cause certain surface regions of the cabinet to exhibit a tendency to be chilled below the dew point of the ambient air, such that condensate or "sweat" forms on these surfaces. One such region is located about the door sealing gasket. This condensate is unsightly and may have a deleterious effect on surface finish and wet the floor areas below these regions and, accordingly, it is sought to be avoided in most refrigerator designs.

If these regions are heated so as to be warmed above the dew point temperature of the ambient air, the formation of such condensate is avoided.

One approach which is currently widely practiced is the use of electric heating cables disposed within the refrigerator cabinet panels which are turned on and off as needed to prevent the condensate formation. While this is relatively simple to incorporate and readily controllable by a manual control switch, electric heating is relatively inefficient and increases the power required to operate the appliance.

The refrigerator system includes structure which is at a relatively elevated temperature, i.e., the compressor and the condenser coil. This relatively warm structure thus represents a possible heat source whenever the compressor is running which does not require an extra energy source. Rather, heat may be utilized which is otherwise merely dissipated into the surrounding room air.

Accordingly, it has heretofore been proposed to utilize a heat transfer system for utilizing this heat source to heat those regions of the refrigerator cabinet which are subject to the formation of condensate. Several examples of such systems are found in U.S. Pat. Nos. 2,141,918; 2,444,667; 2,537,314; and 2,651,187.

These systems typically incorporate a so-called "secondary loop" refrigerant circulation system in which a loop of tubing containing fluid material which can act as a refrigerant is placed in contact with relatively warm portions of the refrigerator structure such as the compressor housing or the condenser loop.

The relatively warm temperature heats the refrigerant within the secondary loop causing it to be vaporized and passed into the upper regions of the loop, which are located at the cabinetry regions to be warmed.

The resultant cooling of the heated refrigerant causes the refrigerant to condense releasing heat to warm the cabinet, the liquid refrigerant flowing back to the warm region in liquid form. Repetition of the cycle allows a relatively effective heat transfer means for utilizing the heat source provided by the warm or hot components of the refrigeration equipment and accordingly does not require any additional power in order to generate the anti-sweat heat.

The warming of the cabinet regions of course represents a thermal load on the refrigeration system. That is, the heat conducted into the interior space of the refrigerator is increased since the secondary loop is often located at regions where insulation is at a minimum causing the refrigeration equipment to be operated longer in order to maintain the refrigerated space at the desired temperature. Thus, this system does inherently create an energy loss which is required in the power to operate the appliance, and if this approach is taken to avoid exterior condensate, some inefficiency is unavoidable.

However, at times, the use of such an anti-sweat system is not required since the dew point of the ambient air may be sufficiently low that the existing temperature of the exterior surfaces will not result in the formation of condensate. This may occur at certain times of the year in certain locales, i.e., during the winter heating season, the extremely dry air within the building will reduce the dew point to the point where cabinet warming is not required. Similarly, in desert climes, the system may never be necessary. While such appliances are generally manufactured to a design adapted to all climates encountered within the market area, the unnecessary heat load could be avoided if the system were not operated.

Heretofore, such secondary loop systems have not been controllable and have been inherently permanently in operation by virtue of their design.

In U.S. Pat. No. 2,651,187, the system is mounted so as to heat the peripheral edges of the access door and in this patent, the heat transfer path is interrupted upon the door being opened. However, no separately operable control member is utilized which could be used to discontinue operation of the secondary loop when the need for cabinet warming is not required. The aforementioned electric cable heating systems generally provide a manually operable switch which allows selective operation of the cabinet heating to conserve power, but heretofore no heating system has been provided for secondary loop or heat transfer type cabinet warming devices.

The specific arrangement disclosed in the listed patents for heating the secondary loop is relatively cumbersome in that it requires relatively permanent affixation to the compressor motor, or portions of the refrigerator frame. This adds to the cost of manufacture.

It is accordingly an object of the present invention to provide a heat transfer cabinet warming device for refrigerator cabinetry in which the cabinet warming process is selectively controllable.

It is another object of the present invention to provide such a device in which a very simple arrangement for the transfer of heat from the heat source is manually controllable by a control member which is manipulated manually to interrupt the transfer of heat into the cabinet areas.

It is still another object of the present invention to provide an arrangement for producing heating of a secondary loop section by an easily installed arrangement and which allows thermal contact to be interrupted.

These and other objects of the present invention which will become apparent upon a reading of the following specification and claims, are accomplished by an arrangement wherein the transfer of heat from the heat source for the warming device is selectively controllable such as to interrupt the transfer of heat whenever the warming is not necessary. This selective interruption is carried out by means of a control member which is positionable in either a first position whereat there is established a conductive coupling of the heat transfer device to the heat source or in a second position whereat there is a conductive decoupling of the heat transfer device from the heat source. The heat transfer device may take the form of a secondary refrigerant loop in which a tubing circuit charged with refrigerant is utilized to act to transfer heat from the condenser coil section of the refrigeration system. The control is then accomplished by sections of the secondary loop tubing and the condenser tubing being brought into contact with each other by a clamping device actuated by a control lever in which a first position clamps together the tubing section to accomplish the conductive coupling and in the second position allows the tubing sections to move apart and release the clamping device to interrupt the conduction of heat to the cabinet. In one particular embodiment, the clamp includes clamping blocks, at least one of which is in contact with the condenser loop and is formed of a conductive material to act as a secondary heat source and to aid in the transfer of heat to the secondary loop when in contact with the condenser loop section.

FIG. 1 is a perspective view of a refrigerator showing in outline form the selectively interruptable cabinet warming device according to the present invention.

FIG. 2 is an enlarged fragmentary view of a portion of the refrigerator cabinetry shown in FIG. 1 showing the details of the warming device control arrangement.

FIG. 3 is a view of the warming device control components shown in FIG. 2 in an enlarged cross sectional view.

In the following detailed description, certain specific terminology will be utilized for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims.

Referring to the drawings and particularly FIG. 1, the refrigerator 10 includes a refrigerator cabinet 12 defining an enclosed interior space and in which an access door 14 is provided in the conventional manner. A refrigeration system is included to cool the interior space which typically includes a compressor 16, a condenser coil 18 and an evaporator coil 20. This system operates in the conventional fashion to compress a refrigerant in the compressor, condensing the hot compressed refrigerant in the condenser coil 18 by radiating the excess heat and allowing the condensed refrigerant to vaporize in the evaporator coil 20 to thereby cool the interior space of the refrigerator.

The compression of the refrigerant in the compressor 16 increases the temperature of the refrigerant so as to become relatively warm or even hot such that the tubing 22 which carries the compressed refrigerant to the condenser tube comprises a relatively warm structure whenever the compressor is running. It is this portion of the refrigeration structure, according to the present invention, which is utilized as a heat source for obtaining heat to warm those portions of the refrigerator cabinetry which are subject to condensate formation.

The heat transfer device is of the type described in the aforementioned patent identified in the Background Discussion, i.e., comprised of a secondary refrigerant loop which serves to transfer heat into the refrigerator cabinet regions whereat the warming is to take place. The term "secondary loop" is utilized to distinguish the same from the refrigerant primary loop, i.e., the refrigeration components including the tubing loop utilized to circulate the refrigerant used to cool the interior space between the compressor, the condenser and the evaporator coils.

The secondary loop 24 is not in fluid communication with this loop, but rather is self-contained and includes a length of tubing which extends about the refrigerator cabinetry in locations whereat the warming is to be accomplished and also extends into the lower region of the cabinet to a point whereat a section of the secondary tubing passes adjacent to a section of the secondary refrigerant loop which contains a relatively hot compressed refrigerant intermediate the compressor 16 and condenser coil 18. The heat transfer device includes the secondary loop 24 which is charged with a refrigerant fluid such that upon being heated in low regions of the cabinet, the refrigerant turns to a gaseous or vapor stage and rises through the upper loop sections coming into contact with the relatively cool upper portions of the secondary tubing loop 24. This causes the refrigerant to condense releasing its latent heat of vaporization and causing the cabinetry portions adjacent thereto to be warmed. Upon condensation of the secondary refrigerant to its liquid state, the refrigerant flows downwardly into the lower regions of the secondary loop to thus provide a mechanism for transferring heat from the hot condenser loop to the selected portions of the refrigerator cabinetry.

According to the concept of the present invention, this arrangement is selectively interruptable by means of a control member which may be manually moved independently of the access door 14 and which serves to conductively couple and decouple a section 26 of the secondary loop 24 with a relatively warm structure utilized as a heat source, i.e., in this case a section 28 of the condenser loop tubing. The control member in a first position causes the tubing sections 26 and 28 to be conductively coupled to each other by being brought into contact with each other, and in a second position causes the tubing sections to be moved apart to thus be conductively decoupled from each other.

This arrangement is best seen in FIGS. 2 and 3 in which the adjacent sections of the condenser loop 28 and secondary loop 26, respectively, pass between a pair of clamping members comprised of clamping blocks 30, 32 which are pivotally mounted at one end at 34 so as to be relatively movable toward and away from each other. Clamping blocks 30, 32 act as clamping means for clamping the secondary section 26 and condenser tubing section 28 together or allowing them to move apart.

The tubing sections 26 and 28 are positioned so as to be biased apart by their mounting within the cabinetry 12 such that upon release of the clamping means, the tubing sections move apart.

Each of the clamping blocks 30 and 32 are formed with arcuate recesses 35 and 36, respectively, each receiving a respective tubing section 26 and 28 to accurately guide them into contact with each other in the conductively coupled position.

The clamping block 32 remains stationary as the clamping block 30 is pivoted and is constructed of a thermally conductive material so as to act as a secondary heat source. For this purpose, the condenser tubing loop 28 is normally positioned in contact with the clamping block 32 so as to continue to heat the clamping block 32 even when the clamping device is released. The secondary loop section 26 is thereby warmed by contact with the clamping block 32 as well as by the contact with the condenser tubing loop section 28 improving the response of the unit upon activation of the clamping device.

The movable clamping block 30 is likewise constructed of a thermally conductive material such as a metal to increase the conductive flow of heat into the secondary loop section 26, when the clamping device is activated.

The relatively movable clamping block 30 is positioned by means of a control member comprised of a control rod or lever 38 which is pivotally mounted at 39 at a point intermediate its length with an end portion 41 being bent and passing into a bracket 43 attached to the clamping block 30 such as to be drivingly connected thereto.

The upper end of the lever 38 extends upwardly within the interior of the refrigerator cabinet panel and has a terminal end 40 extending into the interior space 42 and offset as shown to be confined within a slotted bracket 44. The slotted portion 46 accommodates the pivotal movement of the upper portion of the control lever 38 and bears indicia indicating the "power saver" off and on positions of the control lever 38.

The control lever 38 is internally confined within the cabinet walls as indicated in FIG. 2 with the final terminal end 40 extending into the interior space 42 of the cabinet with a slotted opening provided to accommodate the movement of the end 40 of the control lever 38.

In the off position, the "power saver" feature is inactivated. That is, the cabinet warming is activated and the secondary loop section 26 and the condenser loop section 28 are moved into thermal contact, i.e., conductively coupled, by means of clamping block 30 being pivoted about the pivotal mount 34 to create the heat transfer from the condenser loop into the secondary refrigerant loop and the heating of the refrigerator cabinetry regions whereat the secondary loop is disposed.

In the "power saver" on condition, the secondary loop is conductively decoupled from the heat source by movement of the control lever 38 clockwise as viewed in FIG. 3 so as to pivot about pivot mount 39 and cause the clamping block 30 to be rotated away from the clamping block 32 allowing the secondary loop section 26 to move away from the condenser loop section 28 to thermally decouple the secondary loop from the condenser loop section 28 and the clamping blocks 30 and 32.

An arrangement has thus been provided for very simply and effectively allowing a selective control over the cabinet warming with a secondary refrigerant loop system. This is accomplished with a simple but highly reliable structure which should not add significantly to the cost of the appliance and enable realization of the power saving and overall efficiency improvement of the refrigerator in those situations in which the cabinet warming feature is not necessary.

Many variations of this concept are of course possible, such as the use of other portions of the refrigerator as a heat source, i.e., structural members heated by proximity to the compressor, condenser. Alternate arrangements for interrupting the transfer of heat from the heat source and the heat transfer device are also possible.