Patent ID: 6418277
Filing Date: 2002-07-09
Classification: H05B

Abstract:
An immersible, electrical device for heating liquids, which comprises:at least one positive temperature coefficient (PTC) thermistor heating element having generally parallel, flat, contact surfaces; a pair of plate members formed of an electrically insulating and thermally conductive material having generally parallel, flat, inward- and outward-facing contact surfaces and wherein said inward-facing contact surfaces are coated with a thermally and electrically conductive metal; a pair of heat radiation members formed of an electrically and thermally conductive material, each comprising: a plate portion having a generally flat, inward-facing, contact surface for thermally conductive contact with said outward-facing contact surfaces of said plate members and a plurality of generally outwardly extending cooling fins formed on said plate portion; electrode means about said at least one heating element operative to provide thermally and electrically conductive contact with said contact surfaces thereof and thermally conductive contact with said inward-facing contact surfaces of said plate members; means for fastening said heat radiation members about said plate members such that said inward-facing, contact surfaces of said plate portions are held in thermally conductive contact with said outward-facing contact surfaces of said plate members thereby to define therewith thermal interfaces, said means for fastening being further operative to fasten said plate members about said electrode means and said electrode means about said at least one heating element such that said inward-facing, contact surfaces of said plate members are held in electrically and thermally conductive contact with said electrode means and said electrode means are held in electrically and thermally conductive contact with said flat contact surfaces of said at least one heating element thereby to define therewith thermo-electric interfaces; enclosing means formed of an electrically and thermally insulating material and formed for positioning around said at least one heating element and between said plate portions of said heat radiation members so as to prevent any liquid from coming into contact with the interior of said heating device; and terminal means attached to said electrode means, operative to permit flow of electric current therethrough, across said interfaces, and via said at least one heating element, thereby producing thermal energy therein and operative to prevent any liquid from coming into contact with the interior of said heating device; wherein, when an electrical current passes through said electrical heating device, thermal energy from said at least one heating element is conducted across said interfaces to said heat radiation members.