Chemical vapor sensor
First Claim
1. A chemical vapor sensor comprising:
- an infrared source for generating infrared waves;
an infrared detector in optical communication with the infrared source, and configured to measure the intensity of the infrared waves generated from the infrared source;
a vapor concentrator comprising;
a vapor adsorber;
a heating source to heat the vapor adsorber;
an infrared absorption cell in optical communication between the infrared source and infrared detector, and defining an inlet for taking in air from the vapor concentrator, and an outlet for expelling air, wherein the infrared waves pass through the infrared absorption cell;
an air flow source configured to control air flow through the vapor adsorber and through the infrared absorption cell; and
a microcontroller configured to control the air flow source, such that the air flow source is activated to flow air into the vapor concentrator, deactivated when the heating source is heating the vapor adsorber, which releases a concentrated vapor from the air, activated to flow the concentrated vapor into the path of the infrared waves in the absorption cell, deactivated when the infrared detector measures the intensity of the infrared waves that pass through the infrared absorption cell and the concentrated vapor, and activated to purge the infrared absorption cell.
5 Assignments
0 Petitions
Accused Products
Abstract
A chemical vapor sensor is provided that passively measures a chemical species of interest with high sensitivity and chemical specificity. In an aspect, ethanol vapor in a vehicle cabin is measured, and sufficient sensitivity is provided to passively detect a motor vehicle driver that exceeds a legal limit of blood alcohol concentration (BAC), for use with vehicle safety systems. The sensor can be situated in an inconspicuous vehicle cabin location and operate independently without requiring active involvement by a driver. A vapor concentrator is utilized to amplify a sampled vapor concentration to a detectible level for use with an infrared (IR) detector. In an aspect, in comparison to conventional chemical sensors, the sensitivity of detection of ethanol vapor is increased by a factor of about 1,000. Further, a single channel of infrared detection is utilized avoiding spurious infrared absorption and making the chemical vapor sensor less costly to implement.
8 Citations
23 Claims
-
1. A chemical vapor sensor comprising:
-
an infrared source for generating infrared waves; an infrared detector in optical communication with the infrared source, and configured to measure the intensity of the infrared waves generated from the infrared source; a vapor concentrator comprising; a vapor adsorber; a heating source to heat the vapor adsorber; an infrared absorption cell in optical communication between the infrared source and infrared detector, and defining an inlet for taking in air from the vapor concentrator, and an outlet for expelling air, wherein the infrared waves pass through the infrared absorption cell; an air flow source configured to control air flow through the vapor adsorber and through the infrared absorption cell; and a microcontroller configured to control the air flow source, such that the air flow source is activated to flow air into the vapor concentrator, deactivated when the heating source is heating the vapor adsorber, which releases a concentrated vapor from the air, activated to flow the concentrated vapor into the path of the infrared waves in the absorption cell, deactivated when the infrared detector measures the intensity of the infrared waves that pass through the infrared absorption cell and the concentrated vapor, and activated to purge the infrared absorption cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 22)
-
-
9. A passive chemical vapor sensor for sampling ethanol vapor from a vehicle cabin comprising:
-
an infrared source for generating infrared waves; an infrared detector in optical communication with the infrared source and configured to measure the intensity of the infrared waves generated from the infrared source; an infrared filter for selecting a range of infrared frequency or wavelength that is adsorbed by a predetermined chemical species of interest; an infrared absorption cell in optical communication between the infrared source and the infrared detector, and defining an inlet for taking in air, and an outlet for expelling air, wherein the infrared waves pass through the infrared absorption cell; a vapor concentrator in communication with the infrared absorption cell, comprising; a vapor adsorber; and a heating source to heat the vapor adsorber; an air flow source for controlling air flow through the vapor adsorber and through the infrared absorption cell; and a microcontroller configured to control the air flow source, such that the air flow source is activated to flow air into the vapor concentrator, deactivated when the heating source is heating the vapor adsorber, which releases a concentrated vapor, activated to flow the concentrated vapor into the path of the infrared waves in the absorption cell, wherein the infrared detector measures the intensity of the infrared waves that pass through the infrared absorption cell and the concentrated vapor, and activated to purge the infrared absorption cell. - View Dependent Claims (10, 11, 12, 13, 14, 15, 23)
-
-
16. A method of measuring a chemical vapor concentration comprising:
-
passing air, including sample vapor, by an air flow source through an adsorber; measuring an output (designated Voff) of an infrared detector, with an infrared source deactivated; heating the adsorber, wherein the air flow source is deactivated while the adsorber is heated; measuring an output (designated Von) of the infrared detector, with the infrared source activated; passing concentrated sample vapor from the adsorber into and through the infrared absorption cell at a predetermined time, which comprises the steps of; activating the air flow source long enough to transfer concentrated sample vapor from the adsorber into the infrared absorption cell; holding the concentrated sample vapor in the infrared absorption cell for a predetermined time by deactivating the air flow source; and activating the air flow source again to purge the adsorber and the infrared absorption cell of the concentrated sample vapor; measuring a change in an output (designated Vsig) of the infrared detector; and
calculating the ratio Vsig/(Von-Voff). - View Dependent Claims (17, 18, 19, 20, 21)
-
Specification