Improvements in or relating to means for automatically controlling the temperature of electric heating apparatus

Abstract

Abstract 144,669. Soc. Anon. des Etablissements L. Bleriot. Feb. 5,1919, [Convention date]. Heating by electricity.-Heating-elements, for instance, for a flat-iron, are arranged in two pairs to form the arms of a Wheatstone-bridge temperature-controlling device, one pair a being of material such as carbon, boron, or constantan, having a negative or nil temperature, coefficent, and the other pair b of material such as nickel having a positive coefficient; the difference of potential across the points e, f produced by a rise in temperature causes the winding j of an electromagnet to attract an armature k and insert a high resistance l in the circuit or to open the circuit. The magnet may have one or more additional windings in series or shunt with the resistance l to attract the armature when the potential across the points e, f falls owing to the insertion of the resistance. Variations in the reluctance of the electro-magnet may be compensated by means of the resistance i or a part, of it. In another arrangement, the electro-magnet is replaced by a heating-coil and a thermal switch in the form of a bimetallic strip.

Inventors

No inventors recorded.

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