Wei Dong Xu

US Patent:

8203707, Jun 19, 2012

Filed:

Nov 13, 2007

Appl. No.:

11/938781

Inventors:

Wei Xu - Winchester MA, US

International Classification:

G01J 3/44

US Classification:

356301

Abstract:

The present invention relates to a method and apparatus for distributed sensing utilizing optical scattering in optical waveguides and reveals two types of the invention. One type of the invention is to characterize optical scattering while actively controlling the temperature of the optical waveguide. The other type of the invention is to characterize optical scattering while strain/stress is induced into the optical waveguide through interaction of the jackets or coatings of the optical waveguide with objects under test. In one embodiment of the invention, the optical scattering based method and apparatus can sense liquid level, liquid distribution, and temperature gradient on ground and in low gravity. Other embodiments of the invention can detect location and concentration of liquid spill and gas leak along pipelines, or measure liquid or gas flow rates. Moreover, the method and apparatus described in the invention have capabilities of sensing multiple physical and chemical parameters using one sensing optical waveguide.

US Patent:

20080029702, Feb 7, 2008

Filed:

Jul 23, 2007

Appl. No.:

11/781948

Inventors:

Wei Xu - Winchester MA, US

International Classification:

G01N 21/31

US Classification:

250338500

Abstract:

The present invention is a method and apparatus for remotely detecting methane gas in mines by laser remote sensing technologies. The apparatus has at least one light source emitting photons towards mine walls and at least one light detection device accepting photons reflected from mine walls. When methane gas presents at the optical path, these photons experience strong optical attenuation and indicate methane existence. The invention employs tunable laser spectroscopy technology to measure the concentration path length vectors. The invention further uses tomography algorithms to determine existence, concentration and distribution of methane gas from the measured concentration path length vectors. Explosions due to mix of methane mine gas with air can be prevented by sensing methane existence and minimizing its concentrations through methane drainage and ventilation.