Patent ID: 7499169
Filing Date: 2009-03-03
Classification: G01N

Abstract:
1. An apparatus comprising: an instrument enclosure; a light source positioned within the instrument enclosure that emits a light beam; a beam splitter disposed to split the light beam into a first split beam and a second split beam; a sample chamber configured to accept a flowing humidified gas stream, the sample chamber disposed so that the first split beam passes through the sample chamber over a sample chamber path length; a first detector positioned within the instrument enclosure and disposed in the path of the first split beam after the first split beam passes through the sample chamber, the first detector quantifying a first intensity of light transmitted in the first split beam as the first split beam traverses a first instrument enclosure path length within the instrument enclosure and the sample chamber path length; a second detector positioned within the instrument enclosure and disposed in the path of the second split beam, the second detector quantifying a second intensity of light transmitted in the second split beam as the second split beam traverses a second instrument enclosure path length within the instrument enclosure, the second instrument enclosure path length being equal to the first instrument path length; and a controller configured to receive and interpret a first signal from the first detector and a second signal from the second detector to calculate the water vapor partial pressure or density in the flowing humidified gas stream.