Self-regulating heating element for flowing gaseous medium e.g. air for vehicle engine

摘要

The element combines a strip conductor (1), having little or no temperature coefficient of specific resistance, and a sleeved wire conductor (2) having a positive coefficient. The sleeve (13), e.g. of nickel-chrome alloy, is insulated from the wire (11) by a layer (12) e.g. of magnesia ceramic. The wire is connected in series with the strip and thermally coupled to it throughout its length. Both the strip and the wire may consist of parallel-connected portions. The sleeve also provides corrosion protection for the wire.