Electric baseboard heater control
First Claim
1. Apparatus for controlling an electric heater having a heating elements capable of producing heat for heating a room when connected to a house a.c. power source, the apparatus comprising:
- a) a thermostat system including a temperature sensing device which produces a signal related to air temperature in the room,b) said thermostat system including temperature comparison circuitry providing a comparison of the air temperature in the room indicated by the temperature sensing device signal with a user set point temperature,c) processing circuitry operatively coupled to said thermostat producing an output corresponding to a power gating signal,d) a semiconductor power gating device for gating power from the house a.c. power source to the heating elements, the gating device receiving said power gating signal and conditionally gating the house a.c. power to the heating elements,e) said processing circuitry determining a percentage or fraction of maximum power from the house a.c. power source to be applied to the heating elements by controlling the application of the gating signal to the power gating device, the percentage or fraction of maximum power slowly being varied based upon the comparison of the temperature of the room with the set point temperature,f) said processing circuit changing the output gating signal to the power gating device at intervals of time less than a normal hysteresis time interval of the temperature comparison circuitry.
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Accused Products
Abstract
In order to provide an electric heat system that is quieter than those of the prior art, a switching circuit is incorporated into the controls for the heating system which provides for the heating elements of the electric heater to be kept at a more constant temperature than those of the prior art. The switching circuit regulates the output power to the degree desired while not inducing sharp changes in temperature of the coils of the electric heater and thus reduces the degree of rapid expansion and contraction of the coils and the enclosure for the heater. This in turn reduces the amount of mechanical noise produced by the electric heater while also reducing wear and tear on the heating element, the heater enclosure and objects near to the heater.
33 Citations
14 Claims
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1. Apparatus for controlling an electric heater having a heating elements capable of producing heat for heating a room when connected to a house a.c. power source, the apparatus comprising:
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a) a thermostat system including a temperature sensing device which produces a signal related to air temperature in the room, b) said thermostat system including temperature comparison circuitry providing a comparison of the air temperature in the room indicated by the temperature sensing device signal with a user set point temperature, c) processing circuitry operatively coupled to said thermostat producing an output corresponding to a power gating signal, d) a semiconductor power gating device for gating power from the house a.c. power source to the heating elements, the gating device receiving said power gating signal and conditionally gating the house a.c. power to the heating elements, e) said processing circuitry determining a percentage or fraction of maximum power from the house a.c. power source to be applied to the heating elements by controlling the application of the gating signal to the power gating device, the percentage or fraction of maximum power slowly being varied based upon the comparison of the temperature of the room with the set point temperature, f) said processing circuit changing the output gating signal to the power gating device at intervals of time less than a normal hysteresis time interval of the temperature comparison circuitry. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for controlling application of power from a house alternating current power supply to an electric heater system for heating a room, the method comprising the steps of:
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A) providing a thermostat system which includes a temperature sensing device for comparing temperature in the room with a set point temperature; B) providing processing circuitry operatively coupled to or as a part of the thermostat system; C) determining a desired percentage or fraction of maximum possible heat from the electric heater system and slowly varying that desired percentage based upon the comparison of the temperature of the heated space with the set point temperature; D) providing a power gating device capable of switching or controlling application of power from a house alternating current power supply to the electric heater; E) generating by the processing circuitry a gating signal which controls the power gating device and turns the power on and off to the heating element of the electric heater, the gating signal having a minimum switching time that is less than fifteen seconds and a ratio of power on time to total time being made approximately equal to the desired percentage or fraction of maximum possible heat from the electric heater system. - View Dependent Claims (12, 13, 14)
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Specification