Portable natural gas leak detector

• US 7,710,568 B1
• Filed: 09/26/2008
• Issued: 05/04/2010
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Southern Cross Limited (Southern Cross Healthcare Group PLC)
• Original Assignee: Southern Cross Limited (Southern Cross Healthcare Group PLC), Southwest Sciences Inc.
• Inventors: Petroski, Frank T. Jr., Silver, Joel A., Durkin, Sean, Paige, Mark E.
• Primary Examiner(s): Nguyen; Sang
• Application Number:
  US12/238,819
• Time in Patent Office: 585 Days
• Field of Search: 356/244, 356/246, 356432-444, 356 72- 73, 356/326, 356/328, 250/343, 250/576, 250/372, 250/461.1, 250/339.08
• US Class Current: 356/437
• CPC Class Codes: G01J 3/0264 Electrical interface; User interface
• CPC Class Codes: G01J 3/0272 Handheld
• CPC Class Codes: G01J 3/108 for measurement in the infrared range
• CPC Class Codes: G01J 3/4338 Frequency modulated spectrometry
• CPC Class Codes: G01M 3/38 by using light G01M3/02 takes precedence
• CPC Class Codes: G01N 21/031 Multipass arrangements
• CPC Class Codes: G01N 21/3504 for analysing gases, e.g. multi-gas analysis
• CPC Class Codes: G01N 21/359 using near infrared light
• CPC Class Codes: G01N 2201/0221 Portable; cableless; compact; hand-held

Abstract

The present invention is a portable gas leak detector preferably comprising a portable optical spectroscopy apparatus for measurement of gas concentration.

Claims

1. A portable optical spectroscopy apparatus for measurement of gas concentration, said apparatus comprising:

a laser light source;

a fixed length optical path receiving light from said source and containing a gas to be detected;

a beamsplitter, a sample container containing the gas, a detector receiving light from the sample container, and signal-processing electronics establishing linelockinq and a comparative signal source of said absorption feature;

a detector receiving light at an end of said path;

signal processing electronics acquiring data from said detector; and

a microcontroller receiving said data from said signal processing electronics;

wherein said apparatus is handheld.

2. The apparatus of claim 1 wherein said path comprises a multiple pass optical cell.

3. The apparatus of claim 2 further comprising a pump that continuously pumps said gas through said cell.

4. The apparatus of claim 2 wherein said cell comprises two mirrors configured in a Herriott cell design.

5. The apparatus of claim 1 wherein said source comprises a diode laser.

6. The apparatus of claim 1 additionally comprising a display for displaying said data from said microcontroller.

7. The apparatus of claim 6 wherein said display can switch between displaying said data in PPM, percent LEL and percent gas.

8. The apparatus of claim 1 additionally comprising alarms controlled by said microcontroller.

9. The apparatus of claim 1 wherein said gas is methane.

10. The apparatus of claim 1 further comprising a user button for inputting options and modes.

11. The apparatus of claim 1 further comprising a telescoping sample probe.

12. The apparatus of claim 1 further comprising batteries.

13. The apparatus of claim 1 wherein said apparatus can be held with a single hand.

14. The apparatus of claim 1 further comprising a rigid probe for measurement of underground gas concentrations.

15. A portable optical spectroscopy method for measurement of gas concentration, the method comprising the steps of:

holding a portable optical spectroscopy apparatus in an area to be measured;

emitting light from a laser light source attached to the apparatus;

receiving light via a fixed length optical path from the source and containing a gas to be detected;

employing a beamsplitter, a sample container containing the gas, a detector receiving light from the sample container, and signal-processing electronics to establish linelockinq and a comparative signal source of the absorption feature;

receiving light via the detector at an end of the path;

determining one or more gas concentrations via signal processing electronics connected to the detector; and

reporting the gas concentration data to a microcontroller.

16. The method of claim 15 wherein said source comprises a diode laser.

17. The method of claim 15 wherein the path comprises a multiple pass optical cell.

18. The method of claim 17 additionally comprising continuously pumping the gas to be detected through the cell.

19. The method of claim 17 wherein the cell comprises two mirrors configured in a Herriott cell design.

20. The method of claim 15 additionally comprising displaying the gas concentration data.

21. The method of claim 15 additionally comprising controlling alarms via the microcontroller.

22. The method of claim 15 additionally comprising performing a calibration.

23. The method of claim 15 wherein the gas is methane.

24. The method of claim 15 additionally comprising inputting options and modes via a user button.

25. The method of claim 15 additionally comprising telescoping a sample probe in the area to be measured.

26. The method of claim 15 additionally comprising powering the apparatus with batteries.

27. The method of claim 15 wherein the holding step is performed with a single hand.