Patent ID: 9210739
Filing Date: 2015-12-08
Classification: H05B

Abstract:
1. A heater element for generating heat when connected to an electrical power source, said heater element comprising: an electrically insulating substrate having a first surface and a second surface, a first buss layer made of a conductive material applied to said first surface of said substrate, said first buss layer comprising a first buss and a second buss extending generally along opposite sides of a first heating area of said heater element and a number of alternating first electrodes electrically connected to opposite said first and second busses and extending between said first and second busses; a first layer of a first resistive material, said first resistive material comprising a first positive temperature coefficient material and said first layer being applied in said first heating area of said heater element such as to provide electrical communication between at least selected ones of said alternating first electrodes; a second buss layer made of a conductive material applied to said second surface of said substrate, said second buss layer comprising a third buss and a fourth buss extending generally along opposite sides of a second heating area of said heater element and a number of alternating second electrodes electrically connected to opposite said third and fourth busses and extending between said third and fourth busses; a second layer of a second resistive material, said second layer being applied in said second heating area of said heater element such as to provide electrical communication between at least selected ones of said alternating second electrodes; and a switching element configured for selectively connecting an electrical power source individually to said first buss layer or said second buss layer or concomitantly to said first buss layer and said second buss layer.