Tracer to compensate for environmental variations that influence a chemical vapor sensor measurement
First Claim
1. A chemical vapor sensor that compensates for environmental variations comprising:
- an infrared source for generating infrared waves;
an infrared detector for measuring an intensity of the infrared waves generated from the infrared source;
a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, for concentrating vapor from a sample volume of air, wherein the concentrated vapor is passed into a path of the infrared waves; and
a sampling intake for passively acquiring the sample volume of air and passing the sample volume of air to the vapor concentrator;
wherein a suspect vapor, a first tracer vapor and a second tracer vapor are measured from the sample volume of air, and wherein a processor calculates an adjusted suspect vapor measurement utilizing the suspect vapor, the first tracer vapor measurement and the second tracer vapor measurement.
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Accused Products
Abstract
A chemical vapor sensor is provided that passively measures a suspect chemical species of interest with high sensitivity and chemical specificity, for use with safety systems. A vapor concentrator amplifies a suspect chemical vapor concentration to a detectible level, for use with an infrared detector. Compensation is provided for environmental variations that may influence the passive measurement of the chemical vapor sensor. Environmental variations may include extrinsic vapors in the surrounding air, or air currents that divert the sample vapor as it drifts from the suspect vapor source to a sampling intake. In an example, ethanol vapor is measured and carbon dioxide tracer measurements are used to calculate an ethanol vapor measurement that is adjusted for environmental variations. In an aspect, a time artifact filter sets the output of the carbon dioxide sensor to match the time dependence of the ethanol sensor, to calculate blood alcohol concentration.
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Citations
23 Claims
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1. A chemical vapor sensor that compensates for environmental variations comprising:
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an infrared source for generating infrared waves;
an infrared detector for measuring an intensity of the infrared waves generated from the infrared source;
a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, for concentrating vapor from a sample volume of air, wherein the concentrated vapor is passed into a path of the infrared waves; and
a sampling intake for passively acquiring the sample volume of air and passing the sample volume of air to the vapor concentrator;
wherein a suspect vapor, a first tracer vapor and a second tracer vapor are measured from the sample volume of air, and wherein a processor calculates an adjusted suspect vapor measurement utilizing the suspect vapor, the first tracer vapor measurement and the second tracer vapor measurement. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for passively measuring ethanol vapor from a person and compensating for environmental variations comprising:
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measuring ethanol vapor from a person'"'"'s exhaled respiration, a carbon dioxide first tracer from the person'"'"'s exhaled respiration and a carbon dioxide second tracer from ambient air, and calculating an adjusted ethanol vapor measurement utilizing the ethanol vapor measurement, the carbon dioxide first tracer measurement and the carbon dioxide second tracer measurement. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for passively measuring a chemical vapor and compensating for environmental variations on sampling comprising:
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measuring an intensity of infrared waves generated from an infrared source utilizing an infrared detector;
employing a vapor concentrator including a vapor adsorber and a heating source to heat the vapor adsorber, to concentrate vapor from a sample volume of air, wherein the concentrated vapor is passed into a path of the infrared waves;
acquiring the sample volume of air utilizing a passive sampling intake, and passing the sample volume of air to the vapor concentrator;
measuring a suspect vapor, a first tracer vapor and a second tracer vapor from the sample volume of air; and
calculating an adjusted suspect vapor measurement utilizing the suspect vapor, the first tracer vapor measurement and the second tracer vapor measurement. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23)
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Specification