Patent EA-002704-B1 (EA)
Title: Electrical resistor heating element
IPC: H05B3/14
Filed: 1999-06-14
Abstract: 1. Electrical resistor heating element (1), comprising a flat resistive layer (2) disposed between at least two electroconductive layers (3, 4, 7) forming a sandwich element, characterized in that each is provided with at least one recess (5, 6) made at least in the border region, wherein at least one recess (5) in the first electroconductive layer (3) is offset relative to a second recess (6) in the second electroconductive layer (4) in such a way that each of the electroconductive layers (3, 4) in the zone of the corresponding recess (5, 6) can be contacted selectively in a perpendicular direction to the electroconductive layers (3, 4) on both sides with the corresponding feeder line which can be connected mechanically to them, ), while the contacted conductive layer (3, 4) is accessible on one side through one of the recesses (5, 6) and through the resistive layer (2). 2. The element according to claim 1, characterized in that that the separation of two neighboring recesses (5, 6) is selected large enough so that over the corresponding distance, the resistance of the resistive layer (2) in its plane is at least five times higher than that normal to this plane. 3. The element according to claim 1 or 2, characterized in that it comprises at least one further electroconductive layer (7) separated by an insulating layer (9) from one of the two electroconductive layers (4), where each of the electroconductive layers (3, 4, 7) has at least two recesses (A', B'; B", C'; A", C") and at least one recess (A") of an electroconductive layer (3) is located. at a point (A) at which in only one (4) of the other electroconductive layers no recess is present, so that each current feeder line (33, 34) can be electrically connected - for instance with a crimping clamp known per se - through the recesses (A', A") with the electroconductive layer (4) having no recess in the projection of the corresponding recesses (A', A"). (Fig. 2). 4. The element according to one of the preceding claims, characterized in that along the borders of each of the electroconductive layers (3, 4, 7) groups of recesses - preferably equidistant - are provided. (Fig. 4). 5. The element according to one of the preceding claims, characterized in that the electroconductive layers (3, 4, 7) exhibit additional recesses (II) across the surface which are so arranged that each electroconductive layer (3, 4, 7) has at least one spot not provided with a recess where the corresponding recesses of the other layers are superimposed with the additional recesses (II). (Fig. 4). 6. The element according to claim 5, characterized in that the additional recesses (II) all are arranged in groups - preferably equidistant as a grid along lines (S) in the longitudinal and/or transverse direction in the plane of the electroconductive layers (3, 4, 7) of the resistor heating element (1). 7. The element according to one of the preceding claims, characterized in that the resistive layer (2) has at least one region (21, 23) which is free of resistive mass and preferably contains a filler material that more particularly is a plastic with at most 20 % of the conductance of the resistive mass. 8. The element according to claim 7, characterized in that the at least one region (21) extends over the border region of the resistive layer (2) and/or as a grid along lines (S) in the longitudinal and/or transverse direction of the resistor heating element (1) and is preferably not bonded to the respective neighboring, electroconductive layer. 9. The element according to claim 7 or 8, characterized in that the electroconductive layers (3, 4, 7) each have at least one opening (11) in the plane where these openings (11) in their projections are mutually superimposed and super-imposed with the at least one region (23) in the resistive layer (2) that is free of resistive mass. 10. The element according to one of the preceding claims, characterized in that the resistive layer (2) comprises a support material that is coated with the resistive mass. 11. The element according to one of the claims 5 to 10, characterized in that it is reeled up in a length that is at least 10 times, preferably at least 100 times its width and can be taken off the reel. 12. The element according to one of the preceding claims, characterized in that at least one of the respective outermost, electroconductive layers (3, 7) is covered by an insulating layer (10, 8) on which preferably the position of the recesses (5, 6; A, B, C) and/or openings (11, 23) situated underneath is marked. 13. The element according to one of the preceding claims, characterized in that the resistive layer is essentially porefree while if applicable at least one of the electroconductive layers is a spray metal layer. 14. The element according to claim 9 and 12 fixed to a base, characterized in that a means of fixation, such as a screw penetrates through the openings (11) into the base and protects the resistor heating element against spray water, preferably by means of a ring seal fixed at the bottom side of its head. 15. The element according to one of the preceding claims, characterized in that the resistive layer is made of an electroconductive polymer.