Methods and systems for remote detection of gases

• US 8,269,170 B2
• Filed: 10/15/2007
• Issued: 09/18/2012
• Est. Priority Date: 04/23/2003
• Status: Active Grant

• Current Assignee: Battelle Memorial Institute
• Original Assignee: Battelle Memorial Institute
• Inventors: Johnson, Timothy J.
• Primary Examiner(s): Sung, Christine
• Application Number:
  US11/974,856
• Publication Number:
  US 20120153155A1
• Time in Patent Office: 1,800 Days
• Field of Search: 250/338.4, 250/338.5
• US Class Current: 250/338.5
• CPC Class Codes: G01J 3/108 for measurement in the infrared range
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis

Abstract

Novel systems and methods for remotely detecting at least one constituent of a gas via infrared detection are provided. A system includes at least one extended source of broadband infrared radiation and a spectrally sensitive receiver positioned remotely from the source. The source and the receiver are oriented such that a surface of the source is in the field of view of the receiver. The source includes a heating component thermally coupled to the surface, and the heating component is configured to heat the surface to a temperature above ambient temperature. The receiver is operable to collect spectral infrared absorption data representative of a gas present between the source and the receiver. The invention advantageously overcomes significant difficulties associated with active infrared detection techniques known in the art, and provides an infrared detection technique with a much greater sensitivity than passive infrared detection techniques known in the art.

Claims

1. A system for remotely detecting at least one constituent of a gas, comprising:

a spectrally sensitive receiver positioned at a receiver location, said receiver including an optical component defining a field of view;

an alignment mechanism coupled to the receiver and operable to change the field of view of the receiver by changing the direction in which the receiver is pointed;

wherein the receiver is operable, via the alignment mechanism, to be sequentially pointed at each of a plurality of extended sources of broadband infrared radiation such that the sources are within the field of view of the receiver for discrete periods of time sufficient to collect Fourier Transform spectral infrared absorption data representative of gas present between the source at which the receiver is pointed and the receiver, the sources being separated from one another and separated from the receiver location; and

further comprising means for comparing the Fourier Transform infrared absorption data representative of the gas to known gas infrared absorption information to determine the identity of the gas.

2. The system in accordance with claim 1 wherein surfaces of the sources have dimensions of sufficient size to fill at least about 50% of the field of view.

3. The system in accordance with claim 1 wherein a surface of at least one of the sources has dimensions at least as large as the field of view.

4. The system in accordance with claim 1, further comprising means for determining the concentration of the gas present between the source at which the receiver is pointed and the receiver.

5. The system in accordance with claim 1 wherein the receiver is operably coupled to a processing subsystem operable to compare the Fourier Transform infrared absorption data to information stored in the subsystem to provide comparison results to an operator.

6. The system in accordance with claim 1 wherein surfaces of the sources comprise a thermally conductive material.

7. The system in accordance with claim 1 wherein the receiver is configured to generate an absorption spectrum representative of the gas.

8. The system in accordance with claim 7 wherein the absorption spectrum is encoded as an interferogram.

9. The system in accordance with claim 1 wherein the spectrally sensitive receiver is selected from the group consisting of a spectrometer and a radiometer.

10. The system in accordance with claim 1 wherein the spectrally sensitive receiver is a Fourier Transform Infrared spectrometer.

11. The system in accordance with claim 1 wherein the sources are at least about 5 meters away from the receiver.

12. The system in accordance with claim 1 wherein the sources are from about 20 meters to about 300 meters away from the receiver.

13. The system in accordance with claim 1 wherein the sources are from about 50 meters to about 150 meters away from the receiver.

14. The system of claim 1, wherein each of the sources comprises a surface and a heating component thermally coupled to the surface and configured to heat the surface to a temperature above ambient temperature.

15. A method for remotely detecting at least one constituent of a gas, the method comprising:

pointing a spectrally sensitive receiver at a first source of broadband infrared radiation for a first period of time;

collecting Fourier Transform spectral infrared absorption data representative of a first gas present between the first source and the receiver;

realigning the receiver to point at a second source of broadband infrared radiation for a second period of time, the first and second sources being separated from one another and from the receiver;

collecting Fourier Transform spectral infrared absorption data representative of a second gas present between the second source and the receiver; and

comparing the Fourier Transform infrared absorption data representative of the first and second gasses to known gas infrared absorption information to determine the identities of the first and second gasses.

16. The method of claim 15, further comprising determining the concentrations of the first and second gasses.

17. The method of claim 15, further comprising comparing the Fourier Transform infrared absorption data to information stored in a subsystem to provide comparison results to an operator.

18. The method of claim 15, further comprising generating an absorption spectrum representative of the first and second gasses.

19. The method of claim 15, further comprising positioning the receiver at least 5 meters away from the first and second sources.

20. The method of claim 15, further comprising raising the temperature of surfaces of the first and second sources to a temperature above ambient temperature.