GB713742A - Improvements in the construction of electric heating mantles - Google Patents

Abstract

713,742. Nonconducting coverings for heat. ISOPAD, Ltd., and REIK, H. March 20, 1952 [Dec. 20, 1950]. No. 30993/50. Class 64(2) [Also in Group XI] In an electric heating mantle comprising an inner fabric cover 1 shaped to the bottom of a flask and carrying resistance heating wires and surrounded by cupshaped heat insulating lagging 3 enclosed between the inner cover 1 and an outer cover 2, the connection of the covers is effected by an expansible resilient ring 5 which contracts into a rigid annular recess 6 associated with the outer cover and thereby holds the edge portion of the inner cover in said recess. The ring may be an endless helical spring 5 which is sewn to the edge of the inner, glass fabric cover or is separate from the inner cover and clamps it in the recess. The heating wire or ribbon may be sewn to the inner cover. The recess may be formed in the outside of a sheet metal outer cover 2, or the top of the outer cover may be spun to turn inwardly then upwards and outwards to form a recess 6, Fig. 6, to receive the inner cover held by the spring 5. The outer cover may be flexible and of glass fabric, Fig. 3 (not shown), and a grooved cylindrical ring is placed within its top part, so that the ring 5 holds the edges both of the inner and outer covers in the annular groove. The grooved ririg may be permanently. attached to the outer cover and its lower edge may seat on the upper edge of a stand. The top of the flask may be covered by an over mantle comprising inner and outer cupshaped covers 8, 9 of glass fabric sewn together with an intermediate packing 10 of glass wool. The edge of the downwardly extending outer cover 9 has an endless helical spring 12 sewn thereto, and this ring may contract into the pocket 6 or into an annular groove in or under an annular beading 14 on the outer periphery of the lower outer cover 2. When the over mantle has a side opening, the endless spring 12 may be replaced by a plain ring of spring wire with a gap in it coinciding with the side opening, so that the spring may open when the over mantle is placed on the flask, and will snap into the recess to retain the mantle in place. Reference has been directed by the Comptroller to Specification 623,786, [Group XI].