HEATING ELEMENT AND METHOD OF MANUFACTURE

摘要

A soft and flexible thin heating element made of electrically conductive carbon carrying fabric is impregnated with a soft filling material. The heating element (29) is shaped by curing the soft filling material and cutting the treated fabric into a desired pattern. The electrical contacts (15) are attached to the ends of the serpentine strips which are electrically connected in parallel or in series. The fabric heating element core (29) is sealed to form a multi-layer assembly having at least two electrically insulating layers (12) which envelop each strip of the heating element core. The heating element is made of non-metallic yarns containing electrically conductive carbon/graphite containing fibers which are woven or stranded into the strips, ropes, sleeves or strands of threads. The selected areas of the heating element core are modified to impart additional electrical properties. An optional positive temperature coefficient (PTC) material is incorporated into said selected areas.