Refrigeration – With means preventing or handling atmospheric condensate...
Reexamination Certificate
2000-08-15
2002-08-06
Doerrler, William C. (Department: 3744)
Refrigeration
With means preventing or handling atmospheric condensate...
C062S283000, C062S248000
Reexamination Certificate
active
06427468
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates generally to refrigerated cabinets of the type used in commercial application for housing frozen food products. More specifically, the present invention relates to frost shields for such refrigerated cabinets and, most particularly, to removable frost shields for ice cream dipping cabinets of the type covered by a canopy having a service door.
Refrigerated cabinets are used in commercial installations, such as supermarkets, gas station shops, convenience stores, ice cream shops and the like, for housing frozen food products. One common type of refrigerated cabinet has a open top to provide the customer easy access to frozen foods housed within the cabinet. Cabinets of this type are commonly used in supermarkets for displaying frozen vegetables, frozen juices, packaged ice cream products and the other frozen food products.
Another common refrigerated cabinet has a top canopy having a front window portion on the customer side of the cabinet through which the customer may view the product within the cabinet and a service door, conventionally of either the hinged or sliding type, on the rear, that is server side, of the cabinet. Refrigerated cabinets of this type are commonly used as ice cream dipping cabinets in ice cream shops, but also are used in many other food product display applications in supermarkets and other stores.
In low temperature refrigerated cabinets housing frozen food products, frost commonly forms on the upper portion of the interior walls, i.e. the liner, of the cabinet, particularly above the product fill line. Customarily, the product fill line is several inches below the top edge of the liner as an open volume filled with cold refrigerated air must be provided over the top of the frozen product to protect the product from the warm ambient air in the store. In operation, a certain amount of moist, warm ambient air will inevitably enter the cabinet from the store either through an open top or open service door. Frost formation occurs when this moist, warm air contacts the cold wall of the liner, particularly the upper portion of the liner encompassing the open volume above the food product. Excessive frost formation forms an undesirable insulating barrier between the cold refrigerated surface of the liner and the interior volume of the cabinet. In addition to being unsightly to customers, this frost formation often also reduces heat transfer efficiency and interferes with proper circulation of refrigerated air over the frozen product within the cabinet. As a result, excessive frost formation means increased operating costs.
Frost formation is particularly problematic in ice cream dipping cabinets. Such cabinets typically include a canopy disposed over cabinet base wherein the frozen confection to be served, for example not only ice cream, but also frozen yogurt, sherbet, sorbet and the like, is displayed. Customers can view the product through a window provided in the customer side of the canopy. The individual serving the customer accesses the frozen confection for scooping through a service opening provided in the server side of the canopy. A cover, typically either a hinged lid or a pair of sliding doors, provides for closing the service opening when access is not being made to the interior of the canopied cabinet.
As the service cover is frequently opened during the day to serve customers, frost typically forms rather quickly resulting in the need to defrost the cabinet. As the first step in defrosting an ice cream dipping cabinet, all product must be removed and transferred to another freezer. Once the product is removed from the cabinet, the refrigeration system is shut down and the frost removed either by passing warm air into or spraying warm water on the cabinet interior to melt the frost or by manually scraping the frost from the walls. Obviously, the defrost process is cumbersome and time consuming.
In U.S. Pat. No. 3,858,408, Andre J. Kenyon discloses a refrigerated cabinet having a plurality of detachable frost shields, comprising substantially planar panels, mounted to the upper portion of the liner on the cabinet. In operation, frost forms primarily on the frost shield rather than directly on the liner itself. To defrost the cabinet, the frost shields are removed from the cabinet and the frost thereon readily removed, typically by contacting the frost with hot water. The frost shields are then reinstalled. The disclosed frost shields consist of, generally, of a metallic construction covered with an acrylic enamel finish which is said to provide a sanitary, durable and easy to clean surface. The panels include mounting means at intermittent points along the panel that engage studs extending outwardly from the liner surface. The presence of these studs on the liner surface complicates cleaning of the liner surface and can provide an area where undesirable bacterial growth may establish a foothold resulting in a potentially unsanitary environment.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved detachable frost shield.
It is a further object of a particular aspect of the present invention to provide a pliable frost shield that adheres to the contour of the refrigerated surface via magnetic attraction.
It is a further object of another aspect of the present invention to provide a frost shield that may be easily detached, cleaned and reinstalled.
The frost shield of the present invention comprises a pliable panel fabricated in a layered construction with a relatively thin observe layer of vinyl mounted on nominally thicker back layer of thermoplastic material impregnated throughout with magnetic material, most advantageously a ferrite powder. To facilitate installation and removal, the panel may be provided with handles.
REFERENCES:
patent: 3858408 (1975-01-01), Kenyon
patent: 4781031 (1988-11-01), McElvany
patent: 4818043 (1989-04-01), Borgen
patent: 4940297 (1990-07-01), Borgen
patent: 5339643 (1994-08-01), Pikaart
patent: 5428968 (1995-07-01), Tetsukawa et al.
patent: 5449885 (1995-09-01), Vandecastele
patent: 6141984 (2000-11-01), Perzon et al.
Luyet Ronald E.
Topper Robert T.
Doerrler William C.
Habelt William W.
Shulman Mark
Tyler Refrigeration Corporation
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