Method for Determining the Optical Measurement Path Length in a Duct Gas Monitoring System
AssigneeSiemens Aktiengesellschaft
InventorFredrik Kuoppa
Life of this patent
Estimating the term…
Abstract
Method for determining the optical measurement path length in a duct gas monitoring system in a duct gas monitoring system configured to measure the concentration of a gas component of the duct gas from its wavelength-specific absorption light, wherein light is sent from a light source through a first purging tube, a gas duct and a second purging tube to a measuring detector, the purging tubes open into the gas duct and are flushed with a purge gas which, after flushing, is discharged into the gas duct.
Claims12
-8. (canceled)
A method for determining an optical measurement path length in a duct gas monitoring system configured to measure a concentration of a gas component of the duct gas from its wavelength-specific absorption, the method comprising:
- sending light from a light source through a first purging tube, a gas duct and a second purging tube to a measuring detector, the first and second purging tubes opening into the gas duct and are flushed with a purge gas which, after flushing, is discharged into the gas duct;
- momentarily, during the measuring of the concentration of the gas component, filling the purging tubes with the duct gas;
- calculating an optical measurement path length from a known path length between the light source and the measuring detector multiplied by a ratio of the light absorption measured when the purging tubes are filled with the purge gas and the light absorption measured when the purging tubes are filled with the duct gas, the light absorptions being obtained in temporally adjacent measurements.
A duct gas monitoring system configured to measure a concentration of a gas component of the duct gas from its wavelength-specific absorption to determine an optical measurement path length, comprising:
- a first purging tube;
- a second purging tube;
- a gas duct;
- a measuring detector;
- a purge gas source;
- a pump;
- a duct gas line connected to the gas duct at a point upstream of the first and second purging tubes;
- a light source, the light source and the measuring detector being arranged with respect to the gas duct such that light travels from the light source through the first purging tube, the gas duct and the second purging tube to the measuring detector, the first and second purging tubes opening into the gas duct and being connected to the purge gas source;
- and
- a valve configured to control, during the measurement of the concentration of the gas component, one of momentary switching of the first and second purging tubes from the purge gas source to the pump to draw the duct gas from the gas duct in an opposite purge direction or momentary switching of the first and second purging tubes from the purge gas source to the duct gas line connected to the gas duct at the point upstream of the purging tubes.
Dependencies are inferred from the claim text.