Refrigeration – Processes – Defrosting or frost inhibiting
Reexamination Certificate
2000-09-28
2001-12-04
Bennett, Henry (Department: 3744)
Refrigeration
Processes
Defrosting or frost inhibiting
C062S151000, C062S155000, C062S275000, C062S440000
Reexamination Certificate
active
06324853
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to devices for preventing the accumulation of ice in low temperature refrigeration devices. More particularly, the invention relates to heating devices for facilitating the removal of accumulated ice from the doors and corresponding closure surfaces of low temperature refrigeration devices, including ultra-low temperature freezers.
2. Description of the Prior Art
Low temperature refrigeration devices, especially ultra-low freezers, are commonly used in laboratory settings for storing biological samples. These freezers typically operate between approximately −40° C. and −95° C., and can develop substantial ice build-up around the door seal and closure surfaces depending on frequency of entry, ambient temperature, and humidity conditions. The accumulated ice can have seriously debilitating affects on freezer performance, including interfering with proper door sealing and interior accessibility, and overloading the door latching and mounting mechanisms. Even moderate amounts of ice build-up can so interfere with proper sealing that the required interior temperature cannot be maintained or can only be maintained by overworking the cooling mechanism. When this happens, valuable, perhaps irreplaceable, freezer's contents may be damaged by thawing.
A well-known method of de-icing involves allowing the built-up ice to thaw naturally. This inconveniently entails removing the entire contents of the iced freezer to a second freezer, and waiting for the ice to thaw. Any attempt to artificially hasten thawing, including prying the ice loose, pouring hot water on the ice, or placing space heaters nearby, can damage the door seals or other components of the freezer unit.
SUMMARY OF THE INVENTION
The de-icing system of the present invention presents novel enabling technology operable to facilitate the removal of ice from the door seals and closure surfaces of a low temperature refrigeration or ultra-low freezer device and thereby ensuring proper performance and preventing damage to the device and its contents. The de-icing system employs built-in manually activated heaters and a timing circuit to efficiently and conveniently thaw the accumulated ice. Because the de-icing system focuses heat only on specific, ice-sensitive areas of the freezer, the interior temperature remains relatively constant so that the freezer's contents need not be removed during the de-icing process. The reliable, mechanical timing circuit automatically terminates the process after a predetermined period of time. Optional thermal fuses provide a safety cut-off in the event the heaters exceed a pre-established maximum temperature.
In use, an operator activates the de-icing system a few minutes prior to opening the freezer's door. When the door is opened, the melted or loosened ice can be removed from the door and closure surfaces with a soft cloth. Either the timing circuit or the the thermal fuses will automatically terminate the de-icing process before the freezer's interior storage temperature is detrimentally affected.
These and other important aspects of the present invention are more fully described in the section entitled DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT, below.
REFERENCES:
patent: 2420240 (1947-05-01), Haggerty
patent: 2858408 (1958-10-01), Barroero
patent: 4009586 (1977-03-01), Skvarenina
patent: 4305259 (1981-12-01), Jaescke
patent: 4531376 (1985-07-01), Alsenz
patent: 4827729 (1989-05-01), Groth et al.
patent: 5339643 (1994-08-01), Pikaart
patent: 5682756 (1997-11-01), Lehmiller et al.
patent: 5899078 (1999-05-01), Mager
patent: 0911591 A1 (1999-04-01), None
Kelly Allan D.
Steinhoff Paul
Bennett Henry
Jones Melvin
Pepper Hamilton LLP
SPX Corporation
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