Constant current flame ionization circuit
OwnerPeter P. Payne, Stephan E. Schmidt +4inventors
InventorsPeter P. Payne, Stephan E. Schmidt, Kristin Powers Goppel, Darrell J. King, Stephen M. Tobin, J. Thomas Fowler
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Abstract
In a flame ionization sensor type gas combustion control apparatus, the sensor is provided with a power supply which will increase the voltage as contamination build up occurs on the in-flame sensor electrode thereby keeping a constant sensor current and enabling the sensor to perform as intended even though insulative contaminant build up is present on the electrode.
Claims18
A flame ionization sensor comprising:
- means for sensing resistance of the flame ionization sensor;
- and
- means for supplying increasing voltage to the sensor in response to an increase in the resistance.
A flame ionization sensor comprising:
- a controllable switch for controlling power to the flame ionization sensor;
- means for routing a line voltage to the controllable switch;
- a resistance sensor in series with the flame ionization sensor;
- and
- means for increasing a duty cycle of the controllable switch in response to increased resistance across the flame ionization sensor.
A flame ionization sensor comprising:
- means for routing a line voltage to the flame ionization sensor;
- means for stepping up a line voltage to the flame ionization sensor;
- a controllable switch between the line voltage and the flame ionization sensor;
- means for sensing resistance across the flame ionization sensor;
- and
- means for supplying increased voltage to the flame ionization sensor in response to increased resistance across the flame ionization sensor.
A method of operating an flame ionization sensor comprising:
- running the flame ionization sensor at a first voltage;
- monitoring resistance across the flame ionization sensor;
- and
- supplying the flame ionization sensor with a voltage above the first voltage in response to increased resistance across the flame ionization sensor.
Dependencies are inferred from the claim text.