Importance

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Abstract

A thermal heating and insulating unit is manufactured by molding in situ a block of thermal insulating material about an electrical resistance element. The resistance element is first made from a continuous wire of electrical resistance material and formed into a serpentine configuration with a plurality of segments interconnected by bends at the ends of the segments. In a preferred construction, the segments are straight and the bends at the ends of the segments are in opposite directions. The resistance element is positioned in a mold on a plateau above a porous bottom, the bends overlapping the plateau, and a slurry of inorganic fibers, water and a binder is introduced into the mold to a lever above the plateau, the liquid component of the slurry passing through the porous bottom, and the fibers and a portion of the binder collecting on the porous bottom to form a block with a slot confronting the resistance element, the bends of the resistance element being embedded in the block. The block is then dried to produce a heating and insulating unit.

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First Claim