Heater element having targeted decreasing temperature resistance characteristics
AssigneeWatlow Electric Manufacturing Company
InventorsMark D. Everly, Jeremy Ohse, Patrick Margavio, Sanhong Zhang
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Abstract
A heater is provided that includes at least one resistive heating element having a material with a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile. The heater can include a plurality of circuits disposed in a fluid path to heat fluid flow.
Claims22
A heater comprising:
- at least one resistive heating element comprising a material having a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile.
A heater system for heating a fluid comprising:
- a plurality of circuits arranged in a series within a flow path of the fluid,
- wherein at least one circuit of the plurality of circuits comprises a resistive heating element including a material having a non-monotonic resistivity vs. temperature profile and exhibiting a negative dR/dT characteristic over a predetermined operating temperature range along the profile.
A method of operating a heater system including a resistive heating element having a material with a non-monotonic resistivity vs. temperature profile, the method comprising:
- heating the resistive heating element to within a limited temperature range in which the resistive heating element exhibits a negative dR/dT characteristic;
- operating the resistive heating element within an operating temperature zone that at least partially overlaps the limited temperature range;
- and
- determining a temperature of the resistive heating element such that the resistive heating element functions as both a heater and a temperature sensor.
Dependencies are inferred from the claim text.