Method for making electrical heating mats and blanks therefor

摘要

980,166. Laminar heating elements. R. MEINICH. Nov. 6, 1963 [Nov. 9, 1962], No. 43804/63. Drawings to Specification. Heading H5H. In a process for making laminar heating elements, a web of resistance foil is slotted longitudinally or transversely as illustrated in Figs. 2 and 7 (not shown) to provide a zig-zag resistance path, after which insulating webs are fed on to both sides of the foil and sealed through the slots and round the edge. The composite web is then severed into individual heating mats. Such mats may be buried in walls or floors for room heating. The foil is preferably a lead/tin/ antimony alloy which would melt at about 220‹ C. without causing a fire if it is shortcircuited as by having a nail driven through it. Reinforcement members e.g. threads of nylon thread may be fed with the insulating web in at both edges of the foil.