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US 2011/0297665 A1Published application
Self Regulating Electric Heaters
OwnerRobert Parkerinventor
Life of this patent
Estimating the term…
Abstract
Systems and methods for PTC materials are described. In one example, a PTC constant wattage heater provides two or more self regulating heating modes. The PTC constant wattage heater may provide self regulating temperature and current control at lower expense.
Claims20
A heater, comprising:
- a printed or coated PTC material providing a resistance of 20 to 1500 ohms/sq, the resistance increasing three to five orders of magnitude at a threshold temperature, the printed or coated PTC material in thermal communication with a heated area, the resistance responsive to a temperature of the heated area.
A self regulating heater, comprising:
- a first heating element with a substantially constant impedance;
- a first PTC element in electrical and thermal communication with the first heating element, the first PTC element and the first heating element layered to provide series and parallel electrical couplings between the first heating element and the first PTC element.
A method of operating an electrical heater, comprising:
- in a first mode, providing electrical power to the electrical heater, a first heating element of the electrical heater providing a first thermal output and a second heating element of the electrical heater providing a second thermal output when a temperature of the electrical heater is less than a first threshold temperature;
- and
- in a second mode, providing electrical power to the electrical heater, the first heating element of the electrical heater adjusted to a third thermal output and the second heating element of the electrical heater providing the second thermal output when a temperature of the electrical heater is greater than the first threshold temperature, the third thermal output responsive to a change in resistance of the first heating element.
Dependencies are inferred from the claim text.