GB617081A - Improvements in and relating to electrical resistance heating elements - Google Patents

Abstract

617,081. Electric radiators ; reflector stoves; reflectors. FERGUSON RADIO CORPORATION, Ltd., and GHOSE, S. C. Feb. 9, 1946, Nos. 4096, 4357, 6171, and 18764. [Classes 39 (iii), 75 (ii) and 126] An electric fire adapted to radiate a beam subtending a wide angle at the apparatus in the horizontal plane containing an elongated heating element 10, and subtending narrow angles in planes at right angles to this plane, comprises a main parabolic reflector 13 and an auxiliary reflector 14 which is at least in part of a section derived by halving an arc symmetrical with respect to the plane of projection of the beam and separating the halves above and below the plane of projection. The gap between the two halves may be filled in. In one embodiment, the main reflector 13 is convex viewed in plan from the front, and the heater 10 is curved in a horizontal plane to lie along the locus of the foci of the parabolic reflector. The auxiliary reflector 14, is of a section comprising parts of two parabolas and it is curved to enclose partially the heater 10. In a second embodiment the main reflector is similar to that previously described, except that it is " stepped," that is, is formed of parts of parabolas of increasing focal length, but having a common focus. In this case the heater 10 is straight, but the section of the auxiliary reflector comprises an ellipse, the eccentricity of which varies from zero at the middle of the length of the reflector, to a maximum at each end, the heater lying along the locus of the foci of the ellipses, which form an image of it along the curved locus formed by the foci of the parabolic main reflector. The front portion of the auxiliary reflector is of a section formed by two intersecting circular arcs. In both embodiments the heating element comprises two wires wound on a core of insulating material, the first Provisional Specification stating that separate threads are cut or moulded in the core for this purpose. The heating element may be replaced by a source of light, e.g. an elongated fluorescent tube.