Patent ID: 7263246
Filing Date: 2007-08-28
Classification: G01N

Abstract:
1. An apparatus for detecting gaseous oxygen comprising in combination: (a) an optical fiber having an exterior cladding, a first end and a second end, a portion of the cladding between the first end and the second end being removed from said optical fiber; (b) a coating disposed on the portion of the surface of said optical fiber for which the cladding has been removed, said coating comprising methylene blue, whereby said methylene blue supports an intensity of evanescent radiation from said optical fiber responsive to the level of oxidation of said methylene blue; (c) means for exposing said coating to a gas containing said gaseous oxygen; (d) a light source for generating wavelengths of light in part absorbed by said methylene blue in accordance with the level of oxidation thereof; (e) means for directing the selected wavelengths of light into the first end of said optical fiber; and (f) means for detecting the intensity of selected wavelengths of light exiting the second end of said optical fiber; and (g) means for analyzing the intensity of the selected wavelengths of light detected to determine the change in intensity of the evanescent radiation which is dependent upon the concentration of exposed gaseous oxygen.