Patent ID: 6811751
Filing Date: 2004-11-02
Classification: G01N,Y10T

Abstract:
Apparatus for determining in a person's exhalation air the concentration of a specific substance in the blood by measuring the concentration of said substance and the concentration of water vapor in the exhalation air and utilizing a known relationship between said concentrations, comprising a tube which defines a space for receiving exhalation air, the tube being open at both ends for exhalation air flow from one end to the other, said space communicating with the surrounding air through the open ends thereof, means for selective quantitative detection of said substance in the air in the defined space, a cuvette which is open at one end thereof, said tube being mounted coaxially in the cuvette said one end of the tube being located axially inwardly of the open end of the cuvette and means connected to an annular gap defined between the tube and the cuvette for supplying air to said gap which communicates with the tube at said one end thereof, and an inlet allowing free exhalation into said space at said one end of the tube and allowing air supplied to said gap to escape partly through said inlet flushing the face of a person exhaling into said space.