US 5,861,610 A · Heater wire with integral sensor wire and improved controller for same

Abstract

An improved heater wire and electro-thermal controller suitable for use in electric heating appliances such as electric blankets and heating pads. The heater wire is formed with a first conductor for heat generation and a second conductor for sensing. The first conductor and second conductor are wound as coaxial spirals with an insulation material electrically isolating the two conductors. The two spirals are counter-wound with respect to one another to insure that the turns cross, albeit on separate planes, several times per inch. With the conductors thus formed, if the insulation separating the conductors fails, the first and second conductors will come into electrical contact to facilitate detection of this hazardous condition. The controller of the present invention includes an electronic control unit a sensor input circuit, a heater driver circuit and a user interface circuit. The heater driver circuit is operatively coupled to the first conductor and provides a heater voltage in response to a signal received from the electronic control unit. The sensor input circuit is operatively coupled to the second conductor, measures a resistance and voltage associated therewith, and provides a signal to the electronic control unit in response thereto. The electronic control unit is responsive to signals received from both the user interface circuit and sensor wire input circuit and controls the heater driver circuit accordingly.

Claims17

Dependent claims

A heater wire having an integral sensing wire, the heater wire comprising:

a first conductor, the first conductor having a length and a resistance associated with the length, the first conductor being formed as a helical spiral;
a second conductor, the second conductor having a length and a resistance associated with the length, the resistance of the second conductor predictably varying with temperature, the second conductor being formed as a helical spiral in coaxial relationship with the first conductor helical spiral;
and
a flexible electrical insulator, the flexible electrical insulator being interposed between the first conductor and second conductor such that the first and second conductors are electrically insulated from one another, the flexible electrical insulator further being at least partially thermo-conductive, whereby the second conductor is in thermal communication with the first conductor.

1 more element

An electro-thermal controller for use with a heater wire having an integral sensor wire, the heater wire having a first conductor for heat generation and a second conductor for sensing, each of the first and second conductors having first and second ends associated therewith, the controller comprising:

an electronic control unit;
a heater driver circuit, the heater driver circuit being electrically coupled to the first and second ends of the first conductor and selectively applying a heater voltage thereto in response to a signal received from the electronic control unit;
a sensor wire input circuit, the sensor wire input circuit being electrically coupled to the first and second ends of the second conductor, the sensor wire input circuit measuring a resistance and a voltage associated with the second conductor and presenting a signal to the electronic control unit indicative of the resistance and voltage;
and
a user interface circuit, the user interface circuit being operatively coupled to the electronic control unit, the user interface circuit providing signals to the electronic control unit in response to a user input, the user interface circuit receiving signals from the electronic control unit and providing a visible display in response thereto.

2 more elements

An electric heating appliance comprising:

a heater wire having an integral sensor wire, the heater wire having a first conductor for heat generation and a second conductor for sensing, each of the first and second conductors having first and second ends associated therewith;
and
an electric controller, the controller comprising:
an electronic control unit;
a heater driver circuit, the heater driver circuit being electrically coupled to the first and second ends of the first conductor and selectively applying a heater voltage thereto in response to a signal received from the electronic control unit;
a sensor wire input circuit, the sensor wire input circuit being electrically coupled to the first and second ends of the second conductor, the sensor wire input circuit measuring a resistance and a voltage associated with the second conductor and presenting a signal to the electronic control unit indicative of the resistance and voltage;
and
a user interface circuit, the user interface circuit being operatively coupled to the electronic control unit, the user interface circuit providing signals to the electronic control unit in response to a user input, the user interface circuit receiving signals from the electronic control unit and providing a visible display in response thereto for the user.

5 more elements

Dependencies are inferred from the claim text.

Heater wire with integral sensor wire and improved controller for same

Life of this patent

Heater wire with integral sensor wire and improved controller for same

Life of this patent

Abstract

Claims17