Patent ID: 6046814
Filing Date: 2000-04-04
Classification: G01N

Abstract:
A measuring sensor for subjecting one or more gaseous components in the breathing gases of a subject to analysis by infrared radiation absorption, a gaseous component analyzable by infrared radiation absorption also being present in ambient air, said measuring sensor comprising:a radiation source (1) for emitting infrared radiation along at least one radiation path (R) in the sensor;a sample volume (2) for containing a sample of the breathing gases to be analyzed, said sample volume having a pair of spaced ends defining a measuring absorption length (L1) therebetween, said sample volume being interposed in the radiation path of said sensor so that radiation is applied to a first end, passes through the breathing gas sample in said sample volume along the measuring absorption length, and exits the sample volume through a second end, said radiation source being spaced from said first end of said sample volume, along the radiation path, by a first length (L2);a least one detector (9, 9a, 9b) in the radiation path downstream of said sample volume, said at least one detector being spaced from said second end of said sample volume, along said radiation path, by a second length (L3), the sum of said first and second lengths being at least substantially 20% of said measuring absorption length (L1) of said sample volume;means (8, 8a, 8b, 28) interposed in said radiation path between said radiation source and said detector for establishing a desired wavelength band of infrared radiation; anda solid material transmissive to infrared radiation and substantially homogenous transverse to said radiation path (R), said solid material having a desired rigid and fixed shape and being positioned along the radiation path (R) in at least one of the first and second lengths (L2, L3) of said radiation path to displace ambient air from the radiation path (R) and avoid undesired inaccuracies in the analysis of the breathing gases.