Apparatus for the detection of contaminations, impurities and fibres in textile fibre materials

摘要

Extraneous matter in raw cotton in the form of other fibres, tapes or sheeting cannot be completely removed by customary methods. Some of the foreign particles get as far as the card sliver and then cause yarn breakages and fabric faults and hence relatively high costs. The method described makes it possible to detect such foreign matter in web, sliver or yarn. To this end the fibre material (1) is illuminated with polychromatic light. At least two frequencies of the reflected light are selectively detected and compared. The output signal of the difference circuit (7) used for this purpose is kept constant by a closed loop control circuit (8,9'). As a consequence of a large acting time constant, foreign fibres produce a spontaneous change in the output signal if they differ in colour from the raw cotton. The apparatus described makes it possible, together with a yarn cleaner, to remove foreign fibres whose colour differs from that of raw cotton in the course of rewinding.