Self-regulating heating wire

摘要

The electric heat cable (1) for an electric heating device, comprises two electric conductors (2), a composition of polymer with positive temperature coefficient, an insulating sheath (5), a protection sheath surrounding the insulating sheath, and a metallic screen positioned between the insulating sheath and protection sheath. The conductors are rolled up between them in order to form a twist (4) that is covered by the insulating sheath, and each conductor is surrounded by a layer (3) of the polymer composition having different thickness. The electric heat cable (1) for an electric heating device, comprises two electric conductors (2), a composition of polymer with positive temperature coefficient, an insulating sheath (5), a protection sheath surrounding the insulating sheath, and a metallic screen positioned between the insulating sheath and protection sheath. The conductors are rolled up between them in order to form a twist (4) that is covered by the insulating sheath, and each conductor is surrounded by a layer (3) of the polymer composition having different thickness. The power of heat cable is a function of the rate of twist that varies along the cable. The conductor is a multistrand quasi-round massive metallic wire. Independent claims are included for: (1) an electric heating device; and (2) a process for the fabrication of electric heat cable.