Thermon Manufacturing Company

Chandrakant M Yagnik

David C Goss

Roy E Barth

R Knox Pitzer

Blake E Heimbecker

A heat transfer material comprised of a polymeric material and a nitride or oxide is provided and is thermally conductive, but electrically non-conductive. The polymeric material may be silicone rubber, and the nitride or oxide may be aluminum nitride, boron nitride, silicon nitride, aluminum oxide or beryllium oxide. The material is made flexible by adding plasticizer and remains flexible after an extended period of use. A dielectric jacket for an electrical heating cable is thermally conductive and remains flexible so that it can be reused. The heat transfer material can be used on heating devices such as steam tubes and panels, where the heat transfer material does not bond to or adhere to the heated surface, which allows the heating device to be reused.

Thermally-conductive, electrically non-conductive heat transfer material and articles made thereof

A parallel, zone-type heating cable wherein thermally-controlled ferrite reed switches in each zone regulate current flow to heating elements aligned in parallel with each other. Two parallel conductors deliver current to the switches and the heating elements. A dielectric insulation material separates the conductors from each other and the heating elements. The heating cable may further include a component having a particular temperature coefficient of resistance aligned in parallel with the switch to further regulate current flow to a positive but lesser level when the switch is open.

Switch controlled, zone-type heating cable and method

A flexible electric heating pad has a plurality of positive temperature coefficient (PTC) ceramic thermistor chip heating elements arranged in a two dimensional array between first and second flexible planar sheets of electrically conductive material, preferably woven of copper wire or other electrically conductive fibers. The PTC thermistor chips are disposed in spaced openings in a flexible dielectric separator disposed between the sheets and each chip has opposed planar surfaces soldered, welded or brazed to the sheets to establish electrical and thermal contact therewith. An outer flexible dielectric material covers the external surfaces of the sheets to prevent grounding or shock. A metallic enclosure, for example of stainless steel, can be formed over the outer dielectric material to add corrosion or abrasion resistance to the flexible heating pad.

Flexible electric heating pad using PTC ceramic thermistor chip heating

A flexible heating cable using positive temperature coefficient thermistors as a primary heat source with the thermistors being electrically and mechanically connected to substantially flat, preferably braided, electrical conductors with dielectric material preferably separating the conductors. A covering of dielectric material preferably is used to electrically separate the cable from the environment. The cable construction improves the heat transfer from the thermistors to the environment and improves the temperature distribution of the cable.

Flexible, elongated thermistor heating cable

A parallel, zoned heating cable wherein parallel electrical conductors are spaced outwardly from a central heating element preferably formed of a fibrous material containing carbon or graphite or coated with a conductive polymer. Heat conducting dielectric members are preferably located between the heating element and the electrical conductors for improved thermal distribution of the cable. The conductors are alternately connected by splices to the electrical conductors to produce heat of a constant wattage.

Elongated parallel, constant wattage heating cable

A skin effect heat generating pipe for use with a low frequency alternating current source includes a ferromagnetic pipe (e.g., steel) having thickness substantially greater than the penetration depth of the current of the frequency of the power source. A shunt conductor in the form of an electrically conductive metal layer (e.g., copper) is applied as a discrete layer to the inner surface of the pipe and in electrical contact therewith throughout the length of the shunt conductor, thereby forming a parallel resistance circuit wherein both the shunt conductor and pipe each are capable of conducting substantial current. One end of the pipe is electrically connectable to a first terminal of the power source. A return conductor installed in the pipe and electrically insulated therefrom has one end electrically connected to the second end of the pipe and its other end electrically connectable to the other terminal of the power source. The return conductor can be formed as a discrete inner liner conformed to the inner surface of the layer forming the shunt conductor. The shunt conductor allows a lower voltage level for a given pipe length or a longer pipe length for a given voltage level at the same power output levels.

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Austin, TX, United States of America

Chandrakant M Yagnik