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US 7,158,718 B2Granted
Electric heating device
AssigneeWatlow Electric Manufacturing Company
InventorElias Russegger
Life of this patent
Estimating the term…
Abstract
An electric heating device especially for fluids, such as liquid fuel, includes a heat element with an electrical resistance. The heat element can be connected to an electrical power source and also includes a carrier element to which en electrically conductive heat layer of a PTC material with positive temperature resistance co-efficient is applied. The heat layer can, at least in two interspaced positions, be connected to the electrical power source.
Claims5
An electrical heating device comprising:
- a heating layer applied by a thermal process on a tubular carrier element comprising an inlet and an outlet, the heating layer comprising a PTC material having a temperature resistance curve defining a kink, wherein the kink provides an automatic limit to maintain a constant temperature;
- an injection nozzle disposed proximate the outlet of the tube;
- and
- a displacer disposed within the tubular carrier element such that an annular chamber is formed between the tubular carrier element and the displacer for allowing passage of a fluid to be heated, wherein the fluid does not flow inside the displacer.
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A method of forming an electrical heating device, the method comprising the steps of:
- applying a heating layer to a carrier element using a thermal process selected from a group consisting of plasma deposition, vapor deposition, high-speed flame spraying, and plasma spraying, the heating layer comprising a PTC material having a temperature resistance curve defining a kink, wherein the kink provides an automatic limit to maintain a constant temperature;
- applying an insulating layer over the heating layer using a thermal process;
- and
- engaging a contact ring over the insulating layer such that the contact ring scores the insulating layer to make electrical contact with the heating layer.
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Dependencies are inferred from the claim text.