MULTI-PANE GLAZED DOOR DEFROSTING SYSTEM

摘要

The present invention relates to an electrically heated glazed door structure for use in refrigerated display cabinets. The use of an optically transparent electrically conductive coating for preventing moisture condensation on the frontmost glazed surface of a refrigerated cabinet door is known. Such coatings, normally applied to the unexposed surface of the frontmost glass pane are in current wide use. This heating technique performs well where the ambient air has a relative humidity which is not excessive. When such refrigerated cabinets are used in highly humid environments, it is found that even though the frontmost pane remains frost-free, the innermost pane (the pane which has been exposed to the interior environment of the cabinet) has a tendency to collect condensation while the door is open, The condensation turns to frost when the refrigerated cabinet door is closed, thereby substantially impairing the door's ability to attractively display products stored in the cabinet until such time as the door recovers its frost-free condition. The present invention decreases the frust-free recapture time of a multi-pane glazed door such as is used on refrigerated display cabinets, by selectively heating the innermost pane when it is exposed to high relative humidity conditions. An electric current is passed through an optically transparent electrically conductive layer on the unexposed surface of the innermost pane. This heats the pane to a temperature above the dew point of the ambient air.