Patent ID: 7341563

Claim:
A sidestream carbon dioxide gas sampling system, comprising: (1) a sampling tube having a first end and a second end and adapted to carry a sidestream flow of gas from a sampling site, wherein the sidestream flow of gas is a fraction of a total flow of gas exhaled from a user or inhaled by such a user; (2) a sidestream carbon dioxide gas measurement assembly, including, (a) a housing, (b) a receptacle associated with the housing, (c) a radiation source disposed in the housing on a first side of the receptacle, (d) a radiation detector disposed in the housing on a second side of the receptacle, and (e) a pump disposed in the housing and adapted to draw the sidestream flow of gas into the sampling tube from the sampling site; and (3) a sample cell coupled to the first end of the sampling tube, the sample cell including: (a) a sample cell body, (b) a sample chamber defined in the sample cell body for receiving the sidestream flow of gas from such a user, (c) a first window defined in a first wall of the body and forming at least a portion of a boundary of the sample chamber, wherein the first window is disposed at a location on the sample cell body such that the first window is proximate to the radiation source responsive to the sample cell being disposed in the receptacle, and wherein the first window is substantially transparent to at least one wavelength of radiation to be used in determining a concentration of carbon dioxide disposed in the sample chamber, and (d) second window disposed in a second wall of the sample cell body at opposite sides of the sample chamber, wherein the second window is disposed at a location on the sample cell body such that the second window proximate to the radiation detector responsive to the sample cell being disposed in the receptacle, and wherein the second window is substantially transparent to at least one wavelength of radiation to be used in determining a concentration of carbon dioxide disposed in the sample chamber.