Patent ID: 7556039

Claim:
A sidestream gas sampling system, comprising: a conduit adapted to communicate a flow of gas to a gas measurement site; a gas measurement assembly adapted to measure a constituent of the flow of gas at the gas measurement site; a pressure transducer adapted to measure a pressure of the flow of gas at a first location proximate to the gas measurement site; a capillary tube disposed downstream of the first location and adapted to communicate the flow of gas from the gas measurement site; a differential pressure transducer in fluid communication with a first portion and a second portion of the capillary tube, wherein the first portion and the second portion are spaced sufficiently far apart from one another such that a pressure differential exists therebetween; flow generating means disposed downstream of the capillary tube for generating the flow of gas; and a controller operatively coupled to the pressure transducer, the differential pressure transducer, and the flow generating means, wherein the controller measures the flow of gas based on the output of the differential pressure transducer and controls the rate of flow of gas via the flow generating means based on the measured flow during operation of the flow generating means.