Improved detector and detection method for contaminants in textile materials based on an absorption measurement of light

摘要

A detector and method for detecting contaminants in a measurement object are described where there is compensation for changes in cross-sectional area of the measurement object. Such methods and detectors are suited to detect foreign fibers in yarn slivers in a spinning mill.;The detector comprises a measurement chamber (31), preferably spherical in shape with a highly reflecting inner surface. A tube (34) allows an elongate measurement object such as a sliver to pass through the chamber (31). Absorption of light by the measurement object and/or any contaminant is measured through a transparent window (33).;Light escaping through the ends 35, 36 of tube 34 can be compensated by addition of additional light sources (41, 44) or additional photodetectors (51, 54) inside or outside the measurement chamber (31).