Electrical heating element for use in a personal comfort device

• US 4,910,391 A
• Filed: 08/29/1988
• Issued: 03/20/1990
• Est. Priority Date: 08/29/1988
• Status: Expired due to Fees

• Current Assignee: William M. Rowe
• Original Assignee: William M. Rowe
• Inventors: Rowe, William M.
• Primary Examiner(s): Reynolds, Bruce A.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/237,728
• Time in Patent Office: 568 Days
• Field of Search: 219/549, 219/548, 219/504, 219/505, 174/36, 338/210, 338/212, 338/214
• US Class Current: 219/549
• CPC Class Codes: H05B 3/56 Heating cables

Abstract

An electrical resistance heating element protected against being inimical to the health of a person using the element by enclosing the electromagnetic and electrostatic fields of an electrical current flowing through an electrical heating element providing essentially all of the heat for the element.

Claims

1. An electrical heating element protected against being inimical to the health of a person using the element, comprising:

(a) an electrical heating means for generating heat in proportion to an amount of electrical current flowing therethrough, said heating means providing essentially all of the heat for said element and including a non-conductive core and a conductive resistance portion helically wrapped around said core and a positive temperature conductive polymer surrounding said conductive resistance portions and electrically contacting said conductive resistance portion; and

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(b) means disposed over said electrical heating means for enclosing the electromagnetic and electrostatic fields of the electrical current flowing therethrough including an electrically conductive foil portion wrapped over said conductive polymer and electrically contacting said conductive polymer, said electrically conductive foil portion surrounding and enclosing said conductive polymer for enclosing the electromagnetic and electrostatic fields of the electrical current flowing through said conductive resistance portion.

2. The electrical heating element of claim 1, wherein said electrically conductive foil portion is an aluminum foil.

3. The electrical heating element of claim 1, wherein said nonconductive core and said conductive resistance portion are concentrically and coextensively disposed within said conductive polymer.

4. The electrical heating element of claim 3, wherein said means for enclosing the electromagnetic and electrostatic fields includes a drain wire coextensively and helically wrapped over said foil portion, said foil portion separating said conductive polymer and said drain wire.

5. The electrical heating element of claim 3, wherein said means for enclosing the electromagnetic and electrostatic fields includes a drain wire coextensively and helically wrapped over said conductive polymer between said conductive polymer and said foil portion, said drain wire electrically contacting said conductive polymer and said foil portion.

6. The electrical heating element of claim 1, wherein said electrical heating means further comprises a nonconductive polymer supporting and enclosing said conductive resistance portion.

7. The electrical heating element of claim 6, wherein said means for enclosing the electromagnetic and electrostatic fields includes an electrically conductive foil portion wrapped over said nonconductive polymer, said foil portion surrounding and enclosing said conductive polymer for enclosing the electromagnetic and electrostatic fields of the electrical current flowing through said conductive resistance portion.

8. The electrical heating element of claim 7, wherein said electrically conductive foil portion is an aluminum foil.

9. The electrical heating element of claim 7, wherein said nonconductive core and said conductive resistance portion are concentrically and coextensively disposed within said nonconductive polymer.

10. The electrical heating element of claim 9, wherein said means for enclosing the electromagnetic and electrostatic fields includes a drain wire coextensively and helically wrapped over said foil portion.

11. The electrical heating element of claim 7, wherein said means for enclosing the electromagnetic and electrostatic fields includes a drain wire coextensively and helically wrapped over said nonconductive polymer between said nonconductive polymer and said foil portion, said drain wire electrically contacting said foil portion.

12. An electrical heating element protected against being inimical to the health of a person using the element, comprising:

(a) a nonconductive core and a conductive resistance portion helically and coextensively wrapped around said core, said core and said resistance portion providing an electrical heating means for generating heat in proportion to an amount of electrical current flowing through said resistance portion, said resistance portion providing essentially all of the heat for said element;

(b) a positive temperature conductive polymer surrounding said heating means and electrically contacting said resistance portion, said nonconductive core, said conductive resistance portion and said conductive polymer providing said electrical heating means; and

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(c) means surrounding said conductive polymer and spaced from and enclosing said resistance portion for enclosing the electromagnetic and electrostatic fields of the electrical current flowing through said resistance portion, said means for enclosing the electromagnetic and electrostatic fields electrically contacting said conductive polymer.

13. The electrical heating element of claim 12, wherein said nonconductive core is dacron.

14. The electrical heating element of claim 12, wherein said means for enclosing the electromagnetic and electrostatic fields is an aluminum foil which includes wrapped around said conductive polymer.

15. A method of manufacturing an electrical heating element, comprising the steps of:

(a) melt extruding a polymer over an elongated conductive resistance portion so that said resistance portion is disposed concentrically and coextensively within said polymer;

(b) placing an electrically conductive wrap around said polymer and enclosing the resistance portion;

(c) helically and coextensively wrapping a conductive wire around said electrically conductive wrap; and

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(d) helically and coextensively wrapping a conductive wire around said polymer between said polymer and said electrically conductive wrap.

16. The method of claim 15, wherein the step of placing an electrically conductive wrap around the polymer includes the step of bonding said electrically conductive wrap to said polymer.