Heating element for heating boiling plates, hotplates and the like

A heating element for heating an electrical hot plate, comprising:

• a support of electrically-insulating material;
• a plurality of electrical heating conductors carried by said support and defining a heating area;
• a plurality of connection lines for connecting the heating conductors to a source of electrical energy;
• a switching means adapted to switch connections to said heating conductors and said source, the switching means being operable to make individual, parallel and series connections of said heating conductors to said source, to energize the hot plate in a plurality of power stages;
• a first of said heating conductors being arranged in a first spiral path having a plurality of windings, said first heating conductor extending from an outer end at an outer limit of said heating area to an inner end at a central zone of said heating area and connected at both said ends to at least one of said connection lines;
• and,
• a second and a third of said heating conductors being serially arranged one after the other in a second spiral path interposed between adjacent windings of said first heating conductor, an outer end of said second heating conductor and an inner end of said third heating conductor being arranged at the outer limit and at the central area, respectively, and being there connected to said connection lines, and, the inner end of the second heating conductor and the outer end of the third heating conductor being connected together and to one of said connecting lines, at a connection point situated in the heating area remote from the central zone.