Elektrische Flaechenheizung

摘要

1,256,395. Laminated heating elements. K. GAISER, E. KRAFT, D. GOTZ, and H. HAUSER. 30 April, 1969 [11 May, 1968], No. 22063/69. Heading B5N. [Also in Division H5] A surface heating resistor comprises a layer 3 of graphite in a cold setting, synthetic casting resin, sandwiched between two insulating layers 2, 4, e.g. of synthetic resin, and provided with suitable current supply terminals 7, Fig. 2 (not shown). The layer 3 may be 50-70% polyester resin and 50-30% graphite, and this resin may be 35-45% weakly reactive polyester resin and 10-20% medium reactive polyester resin and up to 5% monomeric reactive ester resin. The mixture also contains conventional accelerators for cold curing purposes, and other additions, such as 1À5-1À7% methylethyl ketone peroxide and paraffin wax. In an alternative, the layer 3 is 40-70% polyurethane resin and 60-30% graphite. Epoxy resins, alkyd resins and phenol resins are further alternatives. The heating layers are applied by coating, painting or spraying or the heating elements are preformed plates or films, possibly strengthened with glass fibres, or are cast in situ. An earthed protective layer 5 and an outer mechanically protective layer 6 are provided. One layer can be provided as a heat storage layer, and the layers 5, 6 preferably have high heat conductivity. Applications to space heating and deicing are mentioned, particularly floors, walls, ceilings, partitions, roads, bridges, terraces, pathways and aircraft surfaces. When the heating layer is a film, it may be calendered and then cut to the necessary dimensions. It can be supplied in long webs or cut pieces. The heating element can be operated direct from the mains supply or via a transformer. Terminals 7 may be perforated strips embedded in the heating layer 3. Alternatively, metal strips line the edges of layer 3 and a plurality of heating elements are interconnected in series or parallel using contact springs between these metal strips. Additional metal strips may be embedded in layer 3 for optional connection to a current supply, e.g. to improve the current distribution or to allow for acceleration of hardening of the heating layer.