Patent GB-1020311-A (GB)
Title: Electrical heating film
IPC: H05B3/26
Filed: 1961-01-20
Abstract: 1,020,311. Electric heating films. P. EISLER. Jan. 19, 1962 [Jan. 20, 1961], No. 2384/61. Heading H5H. In an electric heating film including a conductive foil 11 having narrow elongated staggered openings 15 therein by which a meander pattern is defined comprising substantially parallel arms 12 and bridges joining the ends of the arms, the margins 16 of the foil bounding the long sides of the openings 15 are folded over and back on to the arms 12. Preferably one side of the foil is lacquered, anodized, or otherwise covered with an insulating layer. An insulating film of plastic or elastomeric material, of paper or textile, including glass or quartz fibre cloth may cover both sides of the foil and may extend into the openings 15 where the films may be joined by welding, by adhesives, or by stitching. Alternatively, the openings 15 may be filled by narrow strips of plastic or adhesive material or adhesive covered fabric when manufacturing the film. The foil may be covered by a " dry film adhesive." The margins 14 of the foil may be folded over to form bus-bars or may be partially severed and folded away from the foil to serve as terminal strips. Alternatively, additional strips of metal foil may be stuck by a conductive adhesive to selected parts of the foil pattern to form busbars. These and other methods of making connection to the foil pattern are described in Specification 1,020,316. The foil is preferably provided with crimps 20, and narrow linear zones at which the foil may be folded or cut may be left uncrimped as described in Specification 1,020,312. Although preferably wholly metallic, the foil may comprise any electrically conductive material, e.g. carbon or metal powder, coated on an insulating film. The heating film may be specially shaped for particular applications. A machine for manufacturing the film is described (Figs. 11 to 14, not shown) including means for slitting the foil and folding over the margins 16. Means as described in Specification 1,020,315 may be provided for supplying current to the film to heat it while passing through the machine. Uses of the heating film include attaching it to floor-covering underlays, ceilings or walls, wallpaper, leather cloth, paper, plastic film textiles, moving belts, felting tiles, boards or other floor coverings, motor vehicles, cabins, table tops, packages, lagging around pipes, table cloths, cotton wool, lint and bandages. The film may be used for heating building materials as described in Specification 1,020,314, or for accelerating the setting of concrete, and may be dispensible or may be used again later for purposes such as de-icing. Other uses are for de-icing or freeze-drying as described in Specification 1,020,318, or for melting or increasing the fluidity of a substance in a container as described in Specification 1,020,313. The film may also be inserted in laminates and may be used as an immersion heater or for drying hair or paints, for stoving paints or enamels, for regenerating absorption solids in refrigerators, for soil heating, or for accelerating chemical reactions, and may also be used in place of resistance wire in various heating devices and in clothing.