초록 ▼

The dual path ultraviolet hygrometer makes use of two narrow spectrum light beams of different wavelengths, both of which are transmitted along two geometrically similar paths to measure and compensate for the presence of contaminants and to more precisely measure the water vapor content in the air

The dual path ultraviolet hygrometer makes use of two narrow spectrum light beams of different wavelengths, both of which are transmitted along two geometrically similar paths to measure and compensate for the presence of contaminants and to more precisely measure the water vapor content in the air samples. A first one of these optical wavelengths is highly absorbed by water vapor while the second optical wavelength is only slightly absorbed by water vapor. Both of these generated narrow band light beams are split so that two pairs of light beams are produced. Beams of both wavelengths are transmitted along the first optical path, which traverses the air sampling chamber. By measuring the differential absorption between the two light beams along this first optical path, the water vapor content of the air sample within the air sampling chamber is precisely measured by correcting for contaminant absorption. The second beam of each pair of each wavelength is transmitted along a second optical path, which is geometically similar to the first optical path to measure the strength of each source. By measuring the differential and received intensities of the two sets of light beams, the level of contaminants in the air sampling chamber for both of the light beams can be determined, since the second wavelength is subject primarily to contamination. Therefore, the contamination in the air sampling chamber can be individually compensated at both of the wavelengths to obtain water vapor concentration measurements of greater precision.

대표청구항 ▼

Apparatus for measuring the concentration of a component contained in a sample of a gas, comprising: sampling chamber means for containing said gas sample; first light source means for generating a beam of light at a wavelength that is heavily absorbed by said component; second light source means fo

Apparatus for measuring the concentration of a component contained in a sample of a gas, comprising: sampling chamber means for containing said gas sample; first light source means for generating a beam of light at a wavelength that is heavily absorbed by said component; second light source means for generating a beam of light at a wavelength that is lightly absorbed by said component; means for splitting said light beam from each of said first and said second light source means into first and second pairs of light beams, each of said first and second pairs of light beams including a light beam from said first and said second light source means; means for transmitting said first pair of light beams comprising a beam of light from said first and second light source means through said gas sample contained in said sampling chamber; means for measuring the intensity of said beam of light from said first light source means transmitted through said gas sample contained in said sampling chamber to identify the concentration of said component in said gas sample; means for measuring the intensity of said beam of light from said second light source means transmitted through said gas sample contained in said sampling chamber to identify light beam absorbing contamination in said sampling chamber; light detector means, located in a light path geometrically similar to a light path from said first and second light source means through said sampling chamber to said intensity measuring means that carries said first pair of light beams, for measuring the intensity of said second pair of light beams from said first and second light source means through said similar light path absent said gas sample; means for correcting said measured light intensity for said first and second light beams in said first pair of light beams through said gas sample by said measured light intensity for said first and second light beams of said second pair of light beams through said light path absent said gas sample; and means for correcting said measured transmitted light intensity from said first light source means by said measured light beam absorbing contamination in said sampling chamber.