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Self-testing and self-calibrating detector

  • US 7,017,386 B2
  • Filed: 02/02/2005
  • Issued: 03/28/2006
  • Est. Priority Date: 08/20/2004
  • Status: Expired due to Fees
First Claim
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1. A sensor system comprising:

  • a chemical detector associated with a measurement circuit that produces a measurement of the partial pressure of a gas from the output of the chemical detector, wherein said chemical detector comprises a electrochemical cell;

    a reference gas releasing material comprising a metal hydride, wherein said reference gas releasing material releases a reference gas such that the partial pressure of the reference gas is a function of the temperature of the reference gas releasing material, wherein a heater is positioned to heat the reference gas releasing material;

    a temperature sensor positioned to measure the temperature of the reference gas releasing material and a control circuit that when activated delivers a known partial pressure of the reference gas to the chemical detector by controlling the heat generated by the heater and thereby the temperature of the reference gas releasing material; and

    a calibration circuit that, during calibration, activates the control circuit, reads a measurement called a calibration measurement from the measurement circuit, and produces a calibration factor by comparing the calibration measurement to an expected measurement, while the calibration circuit also, during regular operation, produces a calibrated measurement from the measurement and the calibration factor.

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