Gas sensor calibration method
AssigneeVivante Health, Inc.
InventorAlexander Templeton
Life of this patent
Estimating the term…
Abstract
A method of calibration of gas sensors, including breath gas sensors which are portable and for home, consumer, or medical use, wherein the calibration against samples of a measured gas having a concentration above the null value is only performed once to establish a set of calibration ratios of measured known gas concentration readings over null sample readings. Thereafter, in use, the ratio of unknown gas concentration in a test sample to a null value (preferably ambient air) is determined without recalibration, and that ratio is compared with the set of calibration ratios to determine the unknown gas concentration by interpolation or extrapolation.
Claims16
A method of measuring a target gas concentration in an unknown sample by a gas sensor, where the gas sensor is calibrated once and then need not be calibrated at the time of measuring said gas concentration, comprising:
- a) establishing at least one calibration sample reading on the gas sensor for a calibration sample with a known concentration of target gas;
- b) establishing with the gas sensor a null reading for a first null sample with a concentration of target gas near zero;
- c) determining a calibration ratio of the calibration sample reading and the null sample reading;
- d) establishing an additional null reading on the gas sensor for a second null sample with a concentration of target gas near zero;
- e) determining a test sample reading on the gas sensor for a test sample with an unknown concentration of the target gas;
- f) determining a test ratio of the test sample reading and the additional null reading;
- and
- g) comparing the test ratio to the calibration ratio to determine the concentration of the target gas in the unknown sample by extrapolation or interpolation.
A method of measuring a target gas concentration in an unknown sample by a chemiresistor gas sensor, where the chemiresistor is calibrated once and then need not be calibrated at the time of measuring said gas concentration, comprising:
- a) establishing at least one calibration sample reading on the chemiresistor for a calibration sample with a known concentration of target gas;
- b) establishing with the chemiresistor a null reading for a first null sample with a concentration of target gas near zero;
- c) determining a calibration ratio of the calibration sample reading and the null sample reading;
- d) establishing an additional null reading on the chemiresistor for a second null sample with a concentration of target gas near zero;
- e) determining a test sample reading on the chemiresistor for a test sample with an unknown concentration of the target gas;
- f) determining a test ratio of the test sample reading and the additional null reading;
- g) comparing the test ratio to the calibration ratio to determine the concentration of the target gas in the unknown sample by extrapolation or interpolation;
- and
- h) repeating steps d to g for a third null sample with a concentration of target gas near zero and determining a second test sample reading on the chemiresistor for a second test sample with an unknown concentration of the target gas to determine the test ratio, and comparing the test ratio to the calibration ratio without repeating steps a to c.
Dependencies are inferred from the claim text.