ELEKTRISCH BETRIEBENE TAUCHSCHIEDER UND IHRE REGELUNG

摘要

PCT No. PCT/GB93/00501 Sec. 371 Date Jan. 26, 1995 Sec. 102(e) Date Jan. 26, 1995 PCT Filed Mar. 10, 1993 PCT Pub. No. WO93/18632 PCT Pub. Date Sep. 16, 1993An electric immersion heating element has an elongate, metal-sheathed, electrically insulated, resistance heating portion (1) engaged at its ends in bores formed in an element head (2) which may be formed of a synthetic plastics material, a heat transfer element (8) formed of a high thermal conductivity material extends from a heated part of the resistance heating portion adjacent one of its ends through the element head to enable the element temperature to be sensed from the opposite side of the head, and a tubular enclosure (7) extends from the element head (2) and surrounds the part of the resistance heating portion of the element. The element construction enables dry-boil protection and automatic switch-off on boiling to be achieved by use of a single thermal sensor coupled to the heat transfer element (8) since the steam generated in the enclosure when water boils causes water to be expelled from the enclosure thereby mimicing a dry boil situation.