Patent Application
20070028643
The present invention relates generally to air towers used in refrigeration appliances with a top mount freezer.
A common air circulation arrangement for refrigeration appliances with top mount freezers is to have an air tower located generally at the rear of the refrigeration compartments to guide a flow of chilled air into an upper and a lower refrigeration compartment. For example, U.S. Pat. No. 5,369,963 discloses an air tower construction for use in a top mount freezer refrigeration appliance. Air towers are also disclosed in U.S. Pat. No. 4,920,765 and 5,735,138. Air is directed over an evaporator to chill the air, usually well below 0° C. (32 ° F.) and the chilled air is directed into the air tower to diffuse into the freezer compartment and into the fresh food compartment, at a determined ratio, so that a temperature differential is maintained in the two compartments. Since the air in the tower is usually at a temperature well below the freezing temperature of water, there is a noticeable ice and moisture buildup on the air tower when the product is run in humid conditions. This moisture buildup is due to the fact that moisture from the atmosphere is attracted to the coldest surfaces in the two compartments, such as the evaporator cover and the air tower.
In order to remove ice build up in the freezer compartment, it is known to utilize defrost cycles in which a heater is used to warm the area, particularly associated with the evaporator, at various intervals, such as described in U.S. Pat. No. 3,727,419, so that the user is not required to periodically deenergize the freezer, remove all of the food items, and allow the ice to melt. However, due to the low thermal conductivity of the plastic material normally used for the air tower, all of the frost and ice build-up is not melted from the tower during defrost cycles. This has lead to a significant number of customer complaints and service calls, to remove the ice build up on the air tower, which can restrict the flow of air into the two compartments, and alter the ratio of cold air flowing to the two compartments, thereby altering the preset temperature differential.
It would be an improvement in the art if air towers were provided with a means of reducing the ice build up associated with the air tower, or to enhance the ice removal during defrost cycles.
The present invention provides an air tower construction that enhances the ice melting and removal during defrost cycles.
In an embodiment, an air tower is provided for a refrigeration appliance that has a first cooled compartment and a second cooled compartment. The air tower has a diffuser section with a plurality of vent outlets to communicate with the first cooled compartment. A central duct section is defined by walls extending away from the diffuser section. An outlet is located at an end of the central section opposite the diffuser section to communicate with the second cooled compartment. A first heat trap compartment is formed along one of the walls defining the central duct section.
In an embodiment, the first heat trap compartment comprises an enclosed space formed on an exterior of the central duct section.
In an embodiment, the enclosed space comprises an additional wall spaced from one of the walls defining the central vertical duct section, and connected to the one of the walls at a first end and a second end.
In an embodiment, a second heat trap compartment is formed along one of the walls defining the central duct section.
In an embodiment, the second heat trap compartment is formed along one of the walls which is located opposite one of the walls where the first heat trap is formed.
In an embodiment, the walls comprise a front and two sides of the central section, and the first and second heat trap compartments are formed on an outer side of the two sides of the central section.
In an embodiment, the refrigeration appliance may have a freezer compartment located above a fresh food compartment, with the diffuser section communicating with the freezer compartment.
In an embodiment, the refrigeration appliance may be provided with a refrigeration system, including an evaporator and a defroster heater associated with the evaporator.
In an embodiment, the evaporator may attach to a cover for the evaporator.
In an embodiment, the central duct section may be generally vertically arranged.
The present invention has particular utility in connection with a refrigeration appliance in which a freezer compartment is located above a fresh food compartment, although the invention may also be used with other types of refrigeration appliances utilizing an air tower in connection with two refrigerated compartments, whether they are positioned one above the other or side-by-side. In order to present a description of a preferred embodiment of the invention, a top mounted freezer refrigeration appliance is selected as an environment for the invention, even though the invention is not limited to such an appliance.
In
Cooling within the compartments 22, 24 occurs through the use of a refrigeration system in which a refrigerant is supplied to an evaporator 36 from a compressor 38. Air is directed by a fan (not shown) to flow over the evaporator 36 to cool the air which is then directed into the freezer compartment 22 and refrigerator compartment 24.
The air from the evaporator 36 is discharged into an air tower 40 where the air flow is split into two streams, one stream flowing into the first cooled compartment 22 through vent outlets 42 in a diffuser section 43 of the air tower and the other stream being directed down to the second cooled compartment 24 through a central duct section 44 in the air tower. The central duct section 44 is defined by walls 46, 48, 50 extending away from the diffuser section 43. An outlet 52 is located at an end of the central duct section 44 opposite the diffuser section 43 to communicate with the second cooled compartment 24. Temperature within the second cooled compartment 24 is controlled by an adjustable thermostat (not shown) which can be user adjustable through use of a control knob 53.
As shown in more detail in
A second heat trap compartment 62 may be provided, and as shown, is formed along one of the walls 46, 48, 50 defining the central duct section 44. In the embodiment illustrated, the second heat trap compartment 62 is formed along one of the walls 46, 48, 50 which is located opposite one of the walls where the first heat trap compartment 54 is formed.
In the embodiment illustrated, the walls 46, 48, 50 comprise a front and two sides of the central duct section 44, and the first 54 and second 62 heat trap compartments are formed on an outer side of the two sides 48, 50 of the central duct section. Alternatively, the first heat trap compartment 54 may be formed internally in the central duct section 44 such as along the front wall 46 rather than at an outside of one of the walls 46, 48, 50 defining the central duct section.
The refrigeration appliance 20 may be provided with a defroster heater 64 (
In the embodiment illustrated, the air tower 40 is attached to the cover 66 for the evaporator 36. The evaporator cover has an opening 68 therethrough in a region 70 corresponding to the diffuser section 43 . As illustrated in
During operation of the refrigeration appliance 20, and particularly during a defrost cycle, the defrost heater 64 will be energized to elevate the temperature of the evaporator 36 above the freezing temperature of water. Part of the heated air will flow through the air tower 40 to melt and remove any ice that has formed in the air tower. To enhance the ice melting and removal in the air tower 40, some heat flows via air currents through the passages 72, 76 in the evaporator cover 66 into the heat trap compartments 54, 62. The heat trapped inside of the side compartments 54, 62 will conduct to the central duct section 44, which will assist in melting any ice located there.
The present invention has been described utilizing particular embodiments. As will be evident to those skilled in the art, changes and modifications may be made to the disclosed embodiments and yet fall within the scope of the present invention. For example, various components could be utilized separately or independently in some embodiments without using all of the other components in the particular described embodiment. The disclosed embodiment is provided only to illustrate aspects of the present invention and not in to limit the scope and coverage of the invention. The scope of the invention is e to be limited only by the appended claims.
As is apparent from the foregoing specification, the invention is susceptible of bodied with various alterations and modifications which may differ particularly from at have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.
