Patent ID: 7637308
Filing Date: 2009-12-29
Classification: H05B

Abstract:
1. A heating plate comprising a heating plate body having a heating plate surface, a plurality of elongate cavities passing through the heating plate body underneath the heating plate surface and substantially parallel thereto, electrically heatable rod-shaped heating bodies disposed in the cavities, spacers holding the rod-shaped heating bodies in the cavities out of contact with the wall of the cavities, a heat exchange medium disposed in the cavities for transmitting heat emitted by the heating bodies to the heating plate surface to obtain a uniform temperature across the entire heating plate surface, and connecting means fitted to the cavities to permit circulation of the heat exchange medium through the cavities; wherein the connecting means comprises an inlet for the heat exchange medium, an outlet for the heat exchange medium, and a pump in fluid communication with the inlet and the outlet for recirculating the heat exchange medium in a continuous circuit through the cavities; wherein the cavities have an internal width and length, the ratio of the internal width to the length being at least one to ten; wherein the ratio of the cavity diameter of each cavity to heating body diameter of each heating body is such as to permit operation with a minimum of heat exchange medium.