Heated electrode refrigerant detector utilizing one or more control loop
First Claim
1. A gas detector, operative in conjunction with a power source, for sensing the presence of at least one predetermined gas, the gas detector comprising:
- a detection circuit, the detection circuit including a sensing device having first and second electrodes, wherein the first electrode is connected to the power source for heating the first electrode;
a temperature controller operatively connectable to the detection circuit for maintaining a temperature of the first electrode at a predetermined magnitude;
a current controller operatively connectable to the detection circuit for maintaining a electrical current in the second electrode at a predetermined magnitude; and
a switch adjustable between at least two positions, wherein in a first switch position the temperature controller is operatively connected to the detection circuit and in a second switch position the current controller is operatively connected to the detection circuit, the position of the switch is determined on the basis of an operating condition of the gas detector.
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Accused Products
Abstract
A gas detector for sensing the presence of at least one predetermined gas is operative in conjunction with a electrical power source and includes a detection circuit, a temperature controller, and a electrical current controller, wherein the detection circuit includes a sensing device having first and second electrodes, the first electrode being connected to the power source for heating the first electrode, the temperature controller is operatively connectable to the detection circuit for maintaining a temperature of the first electrode at a predetermined magnitude, and the current controller is operatively connectable to the detection circuit for maintaining a current in the second electrode at a predetermined magnitude.
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Citations
20 Claims
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1. A gas detector, operative in conjunction with a power source, for sensing the presence of at least one predetermined gas, the gas detector comprising:
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a detection circuit, the detection circuit including a sensing device having first and second electrodes, wherein the first electrode is connected to the power source for heating the first electrode;
a temperature controller operatively connectable to the detection circuit for maintaining a temperature of the first electrode at a predetermined magnitude;
a current controller operatively connectable to the detection circuit for maintaining a electrical current in the second electrode at a predetermined magnitude; and
a switch adjustable between at least two positions, wherein in a first switch position the temperature controller is operatively connected to the detection circuit and in a second switch position the current controller is operatively connected to the detection circuit, the position of the switch is determined on the basis of an operating condition of the gas detector. - View Dependent Claims (2, 3)
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4. A method of controlling a gas detector for sensing the presence of at least one predetermined gas, the gas detector having a heated first electrode and a second electrode, herein the method comprises the steps of:
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heating the first electrode to a predetermined absolute temperature;
upon reaching the predetermined absolute temperature, placing the electrodes in a test location;
upon being exposed to one of the predetermined gases, generating an increased electrical current in the second electrode; and
maintaining the first electrode at substantially the predetermined absolute temperature while placing the electrodes in the test location and while generating the increased current. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A gas detector, operative in conjunction with a power source, for sensing the presence of at least one predetermined gas, the gas detector comprising:
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an anode/cathode assembly coated with a ceramic material, the anode/cathode assembly including a cathode wire and an anode wire at least partly surrounding the cathode wire, wherein the anode wire has opposing ends and wherein one of the anode wire ends is electrically connected to the power source;
a pair of supply contacts electrically connected to the respective ends of the anode wire;
a pair of temperature sense contacts electrically connected to respective ends of the anode wire;
a cathode contact electrically connected to an end of the cathode wire;
a temperature-sensing circuit electrically connected to at least one of the temperature sense contacts for monitoring the temperature of the anode/cathode assembly; and
a bias current-sensing circuit electrically connected to the cathode contact.
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12. A system for controlling a gas detector for sensing the presence of at least one predetermined gas, the gas detector having a heated first electrode and a second heated electrode, comprising:
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means for heating the first electrode to a predetermined absolute temperature;
means for placing the electrodes in a test location;
means for generating an increased electrical current in the second electrode; and
means for maintaining the first electrode at substantially the predetermined absolute temperature while placing the electrodes in the test location and while generating the increased current. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19, 20)
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Specification