GB206041A - Electric heating devices - Google Patents

Abstract

206,041. Nobbs, C. G., and Nobbs, W. W. Dec. 13, 1922. Wire resistances, cored and enclosed. - In an electric heating - device particularly applicable for heating mattresses, the heating elements consist of resistance wire wound upon non-hygroscopic insulating material within a watertight tube. The elements preferably comprise nichrome wire 1, Fig. 2, wound upon flat strips 2 of mica which have portions 3 of their length widened to fit closely within a thin metal tube 4, the wire upon the narrow portions being thereby spaced from the internal wall of the tube. A number of elements are joined in series by straigiit wires 7 passing through flexible metallic tubes 6 from which they are insulated by beads of glass or other suitable material. Metallic sockets 5 provide a watertight joint between the tubes 4 and the flexible tubes 6, and short mica tubes 8 are provided to insulate the sockets from the wires 7. Fig. 5 shows one arrangement of the heater within a matress, a socket 12 being provided for connection to an electric circuit. A thermostat of the bimetal type may be included in the resistance circuit to limit the rise of temperatures.