Layered self-regulating heating article
First Claim
1. A self-regulating electrical heating article adapted for connection to a source of electrical power comprising a first layer of material, said first layer exhibiting a positive temperature coefficient of resistance with an associated anomaly temperature Ts and having at least partially contiguous therewith a second layer of constant wattage material having an associated resistance, said article being connectable to an electric power input source whereby current flow is through at least a portion of said first layer and through at least a portion of said second layer, whereby there is both direct electrical and thermal coupling between said first and second layers, and whereby at a temperature which is the higher of the temperature at which the resistance of said first layer exceeds the resistance of said second layer or the anomaly temperature of said first layer, current flow predominantly follows the directionally shortest path through said first layer.
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Abstract
A self-regulating heating article comprising a layer of material exhibiting a positive temperature coefficient of resistance (PTC) and said PTC layer having at least partially contiguous therewith at least one layer of constant wattage output material. The article operates such that when connected to an electric power source, the current flows through at least a portion of the thickness of the PTC layer and of the constant wattage layer. In a preferred embodiment, upon heating the article, a change in dimensions as well as activation of an adhesive occurs.
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51 Claims
- 1. A self-regulating electrical heating article adapted for connection to a source of electrical power comprising a first layer of material, said first layer exhibiting a positive temperature coefficient of resistance with an associated anomaly temperature Ts and having at least partially contiguous therewith a second layer of constant wattage material having an associated resistance, said article being connectable to an electric power input source whereby current flow is through at least a portion of said first layer and through at least a portion of said second layer, whereby there is both direct electrical and thermal coupling between said first and second layers, and whereby at a temperature which is the higher of the temperature at which the resistance of said first layer exceeds the resistance of said second layer or the anomaly temperature of said first layer, current flow predominantly follows the directionally shortest path through said first layer.
Specification