公开(公告)号：EP2507609A1

公开(公告)日：2012-10-10

申请号：EP09801183.6

申请日：2009-12-04

申请人： Siemens Aktiengesellschaft

发明人： KUOPPA, Fredrik

IPC分类号： G01M15/10 ,  G01N21/35 ,  G01N21/53 ,  G01N21/85

CPC分类号： G01N21/85 ,  G01N21/3504 ,  G01N2021/151

摘要： Method for determining the optical measurement path length in a duct gas monitoring system In a duct gas monitoring system which is adapted to measure the concentration of a gas component of the duct gas (2) from its wavelength-specific absorption light (3) is sent from a light source (6) through a first purging tube (15), a gas duct (1) and a second purging tube (16) to a measuring detector (5), wherein the purging tubes (15, 16) open into the gas duct (1) and are flushed with a purge gas which, after flushing, is discharged into the gas duct (1). In order to provide an improved estimate of the optical measurement path length (L), especially when process conditions vary, the purging tubes (15, 16) are, during the measuring of the concentration of the gas component, momentarily filled up with the duct gas (2), and the optical measurement path length (L) is calculated from the known path length between the light source (4) and the measuring detector (5) multiplied by the ratio of the light absorption measured when the purging tubes (15, 16) are filled with the purge gas and the light absorption measured when the purging tubes (15, 16) are filled with the duct gas (2), wherein the light absorptions are obtained in temporally adjacent measurements.