Electromagnetic wave reducing heater

Abstract

A heater with reduced electromagnetic wave emissions, which has two heating elements separated by an insulating layer and receiving opposite-phase alternating current in a way that cancels out electromagnetic wave emissions.

Claims

1. A heater, comprising: a first planar heating element, said first heating element configured to generate heat based on a first alternating current; a second planar heating element, said second heating element configured to generate heat based on a second alternating current; said first planar heating element and said second planar heating element arranged in such a way that the electromagnetic emissions coming from the first planar heating element are opposite in phase from the electromagnetic emissions coming from the second planar heating element, wherein the first planar heating element and the second planar heating element are arranged such that their poles are opposite to each other; wherein the first planar heating element and the second planar heating element are located at a relative position and distance with respect to each other such that the electromagnetic emissions coming from the first planar heating element are cancelled out by the electromagnetic emissions coming from the second planar heating element.

2. A planar heater, comprising: a first planar conductive element made of a conductive material; a second planar conductive element made of a conductive material, the first planar conductive element and the second planar conductive element being arranged such that their poles are opposite to each other; an insulation layer between the first planar conductive element and the second conductive element; a means of delivering alternating current to the first and second planar conductive elements so that a first alternating current delivered to the first planar conductive element is opposite in phase from a second alternating current delivered to the second planar conductive element, so that the electromagnetic emissions coming from the first planar conductive element are cancelled out by the electromagnetic emissions coming from the second planar conductive element.

3. The planar heater of claim 2, where the first and second planar conductive elements are made of metal.

4. The planar heater of claim 2, where the first and second planar heating elements are made of a material impregnated with carbon particles.

Description

LIST OF FIGURES

(1) FIG. 1 shows an exploded view of a planar heating element of the present invention.

(2) FIG. 2 shows an exploded view of an alternate embodiment of a planar heating element of the present invention.

(3) FIG. 3 shows an electrical diagram of a planar heating element of the present invention.

(4) FIG. 4 shows an electrical diagram of an alternate embodiment of a planar heating element of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(5) FIG. 1 shows the preferred embodiment of the invention. Planar conductive elements 1 are connected to electrodes 2. The planar conductive elements can be made of metal, of carbon powder or carbon fibers mixed in a binder and printed, coated, or impregnated on plastic film, fabric, or paper, of carbon fibers mixed in a paper form or carbon felt, or of etched metal foil. The electrodes can be made of either rolled or electrolyzed metal foil. Rolled metal foil is more commonly used thanks to its higher yield strength; a preferred thickness of the metal foil is about 20-60 microns. An insulation layer 3 is placed between the planar conductive elements and on the outside of each planar conductive element. For low-temperature planar heating elements of less than 80° C., polyester or heat-resistant plastic film or sheet is preferable, while for high-temperature planar heating elements of greater than 80° C., high heat resistant hardening resin such as hardening epoxy resin is preferable. The thickness of the insulation layer is preferably 100-200 microns in terms of its insulation characteristics, though it can be greater than 200 microns where excellent insulation characteristics are required. When external wire is connected to copper foil, soldering or wire-connecting terminals are used; the connection must be securely fastened to sustain substantial external force and properly insulated.

(6) FIG. 2 shows an alternate embodiment of the present invention, where the planar heating element 4 is made of metal and comprises a wire disposed in a planar fashion over the surface of the insulation 3. The planar heating element 4 is then connected to electrodes 5.

(7) FIGS. 3 and 4 show the electrical design of the preferred embodiment of the present invention. Electrical signal 10 is opposite in phase from electrical signal 20. As a result, the electromagnetic waves that are generated by one planar conductive element are canceled out by the electromagnetic waves generated by the other planar conductive element.