Abstract A kiln temperature controller is provided comprising a circuit for providing a first signal representative of a selectable kiln temperature and a temperature detection circuit for providing a second signal representative of the detected kiln temperature. The temperature detection circuit comprises first and second thermocouples disposed in the kiln and in the temperature controller, respectively. The first and second thermocouples are coupled in series and in opposite polarity. A solid state temperature sensing circuit is provided in the kiln temperature controller, the temperature sensing circuit being coupled in series with the first and second thermocouples and providing an output signal having a polarity opposite that of the second thermocouple to nullify ambient temperature variations of the kiln temperature controller. The second thermocouple is provided with an isothermal relationship with respect to the solid state temperature sensing circuit and a solid state temperature compensated voltage source is provided for the temperature sensing circuit, the compensated voltage source being provided with an isothermal relationship with the temperature sensing circuit and the compensated voltage source being provided with V be characteristics identical to the V be characteristics of the solid state temperature sensing circuit. A comparator coupled to outputs of the temperature detection circuit and the signal representative of a selected kiln temperature is employed to actuate the kiln and apply heat to the kiln when the detected kiln temperature is below the desired kiln temperature.
A kiln temperature controller comprising: circuit means for providing first signals representative of a selectable desired kiln temperature; temperature detection means for providing second signals representative of the detected kiln temperature, said temperature detection means comprising: a first thermocouple for insertion in a kiln for detecting the temperature within a kiln; a second thermocouple coupled in series with said first thermocouple in opposite polarity thereto, with said second thermocouple positioned in the kiln temperature controller; means for defining a heat sink disposed in the kiln temperature controller; a solid state temperature sensing circuit in the kiln temperature controller, said temperature sensing circuit having a thermal connection to said means for defining a heat sink and said solid state temperature sensing circuit being coupled in series with said first and second thermocouples for providing an output signal having a polarity opposite that of said second thermocouple to nullify ambient temperature variations of the kiln temperature controller such that said temperature detection means provides an output signal accurately representing the detected kiln temperature; said second thermocouple having a thermal connection to said means for defining a heat sink for providing said second thermocouple with an isothermal relationship with respect to said solid state temperature sensing circuit; a solid state temperature compensated voltage source for said temperature sensing circuit; said solid state temperature compensated voltage source being provided with an isothermal relationship with said solid state temperature sensing circuit and said solid state temperature compensated voltage source being provided with V be characteristics identical to the V be characteristics of said solid state temperature sensing circuit; and comparator circuit means coupled to said circuit means and to said temperature detection means for providing control output signals employed for actuating a kiln to apply heat to the kiln when the detected kiln temperature is below the desired kiln temperature.
Claim 2
Dependent Claim
305 words
A kiln temperature controller comprising: circuit means for providing first signals representative of a selectable desired kiln temperature; temperature detection means for providing second signals representative of the detected kiln temperature, said temperature detection means comprising: a first thermocouple for insertion in a kiln for detecting the temperature within a kiln; a second thermocouple coupled in series with said first thermocouple in opposite polarity thereto, with said second thermocouple positioned in the kiln temperature controller; means for defining a heat sink disposed in the kiln temperature controller; a solid state temperature sensing circuit in the kiln temperature controller, said temperature sensing circuit having a thermal connection to said means for defining a heat sink and said solid state temperature sensing circuit being coupled in series with said first and second thermocouples for providing an output signal having a polarity opposite that of said second thermocouple to nullify ambient temperature variations of the kiln temperature controller such that said temperature detection means provides an output signal accurately representing the detected kiln temperature; said second thermocouple having a thermal connection to said means for defining a heat sink for providing said second thermocouple with an isothermal relationship with respect to said solid state temperature sensing circuit; a solid state temperature compensated voltage source for said temperature sensing circuit; said solid state temperature compensated voltage source being provided with an isothermal relationship with said solid state temperature sensing circuit and said solid state temperature compensated voltage source being provided with V be characteristics identical to the V be characteristics of said solid state temperature sensing circuit; and comparator circuit means coupled to said circuit means and to said temperature detection means for providing control output signals employed for actuating a kiln to apply heat to the kiln when the detected kiln temperature is below the desired kiln temperature.
Claim 3
Dependent Claim
24 words
The system as defined in claim 1 and further including temperature display means coupled to said temperature detection means for displaying the kiln temperature.
Claim 4
Dependent Claim
35 words
The system as defined in claim 2 and further including means for selectively coupling said temperature display means to said circuit means for monitoring the desired kiln temperature as it is selected by the operator.
Claim 5
Dependent Claim
31 words
The system as defined in claim 3 wherein said circuit means comprises a selectable DC reference voltage source for providing a DC voltage level to one input of said comparator circuit.
Claim 6
Dependent Claim
36 words
The system as defined in claim 3 wherein said circuit means comprises a staircase generator providing a stepwise ramp voltage with a slope corresponding to a kiln temperature rise time of approximately 270° F. per hour.