Electrical heating element for use in a personal comfort device
AssigneeSpecialty Cable Corp.
InventorWilliam M. Rowe
Life of this patent
Estimating the term…
Abstract
A heated comfort product such as an electrical blanket having an elongate electrical resistance element is connected in a particular manner to an AC power line by connecting the ends of conductors used in the element at a common end to respective AC power lines so as to achieve reduced or non-detectable electromagnetic and/or electrostatic radiating fields from the comfort product.
Claims11
A reduced or non-detectable electromagnetic and/or electrostatic field radiating electric comfort product such as an electric blanket, heating pad or lap warmer and the like and heated by conventional AC power obtained from an electric outlet having a pair of AC power lines, comprising:
- an elongate electric heater cable formed with a pair of electrical conductors which are closely spaced to one another inside the cable;
- said cable having a front end and a terminal end, one of the conductors being helically-wrapped around the other and a positive temperature coefficient material extruded around the other conductor and in electrical contact with both the conductors along their lengths;
- means for connecting the pair of AC power lines to the front end of the heater cable;
- said means connecting one AC power line to one of the electrical conductors at the front end and the other AC power line to the other electrical conductor at the front end so that electric current flows through said closely-spaced conductors in respectively opposite directions along the cable between its front end and its terminal end, so as to substantially reduce the electromagnetic and electrostatic field generated by the electric comfort product when it is heated from the AC power on the AC power lines.
A reduced or non-detectable electromagnetic and/or electrostatic field radiating electric heated comfort product such as an electric blanket, heating pad or lap warmer and the like and heated by conventional AC power obtained from an electric outlet having a pair of AC power lines comprising:
- an elongate electric heater cable formed with first and second spaced-apart electrical conductors arranged in a coaxial relationship;
- a non-conductive core;
- said first conductor being helically-wrapped in a first direction around the core;
- a PTC resistive material extruded around the first conductor and being electrically-coupled to the first conductor along their respective lengths;
- said second conductor being helically-wrapped around the PTC resistive material and electrically-coupled thereto along their respective lengths;
- an insulating jacket extruded around the second conductor;
- and
- a control coupled to connect the AC power lines respectively to the first and second conductors at a common end of the heater cable.
Dependencies are inferred from the claim text.