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Additionally, the electrical heating element may comprise a heat spreading element 210. In general terms, the heat spreading element 210 is a layer or material capable of drawing heat from the resistive element 208 and distributing the heat energy away from the resistive element 208. Specifically, the heat spreading element 210 may comprise a metallic foil, graphite, a composite material, or other substantially planar material. Preferably, the heat spreading element 210 comprises a material that is thermally isotropic in one plane. The thermally isotropic material may distribute the heat energy more evenly and more efficiently. One such material suitable for forming the heat spreading layer 210 is GRAFOIL® available from Graftech Inc. located in Lakewood, Ohio. Preferably, the heat spreading element 210 is a planar thermal conductor. In certain embodiments, the heat spreading layer 210 is formed in strips along the length of the resistive element 208. In alternative embodiments, the heat spreading element 210 may comprise a contiguous layer. In certain embodiments, the heat spreading layer 210 may cover substantially the full surface area covered by the thermal cover 200 for even heat distribution across the full area of the thermal cover 200.

Added by DJM 2 2021