GB221180A - Improvements in electrical heating elements - Google Patents

Abstract

221,180. Wiegand, E. L. Aug. 31, 1923, [Convention date]. Wire and ribbon resistances, embedded and encased.-In an electrical heating element of relatively thin cross-section and large surface area and wherein a resistor is enveloped in refractory material within a sheet metal casing, the refractory material, such as magnesium or zirconium silicate, to which may be added clay as a binding medium, is highly compacted about the resistor by pressure. As illustrated in a strip type of heating element the resistor 1, preferably in zig-zag form, is embedded in compacted refractorv matetrial 2 within a metal casing composed of a channel receptacle 5 having sides 7 which are bent over a cover 6. Terminals 3, preferably of the type described in Specification 219,084, [Class 38 (i), Electric couplings &c.], are provided, and the ends of the casing are flattened at 8 and provided with hole 9 for attaching the element to the article to be heated. A portion of the casing may be perforated and the strip may be bent to various shapes. Other shaped heating elements are described, and the walls of the casing may be connected by eyelets. The Specification as open to inspection under Sect. 91 (3) (a) comprises also a process for preparing these elements wherein the receptacle 5 is first partly filled with refractory material, the resistor is inserted, preferably by means of the apparatus described in Specification 221,894, [Class 87 (ii), Moulding plastic &c. substances]. the receptacle is filled with refractory material and pressure is applied. The cover is next put in place, the edges of the receptacle are bent over, and heavy compacting pressure applied. This subject-matter does not appear in the Specification as accepted. Reference has been directed by the Comptroller to Specifications 140,738, 165,443 and 181,940.