ELECTRIC HEATING ELEMENT (ALTERNATIVES) Russian patent published in 2005 - IPC

FIELD: electrical engineering; electric heating elements for overheat-protected tubular electric heaters.

SUBSTANCE: heating element of first design alternate has high-resistivity metal wire spiral, heat-responsive section in the form of easy-melting metal alloy tube, metal plug inserted in spiral at its end disposed on heat-responsive section end, and contact in the form of metal tube secured thereon, partially fitted onto heat-responsive section, and rigidly fixed thereto. Spiral turns are joined together on length from end of spiral to at least plug to form rigid part of spiral. This rigid part is partially fitted onto heat-responsive section and joined to the latter so that distance through symmetry axis between rigid part of spiral and contact ensures opening of heating element circuit when heat-responsive section temperature exceeds critical value equal to melting point of its material. As an alternative, heat-responsive section may be soldered to metal plug. Heating element of second design alternate has two high-resistivity metal wire spirals and heat-responsive section is installed on two ends just as in first design alternate.

EFFECT: simplified design, reduced operating time of heat-responsive section.

4 cl, 8 dwg