| 摘要 |
PURPOSE:To detect impurities in pulp by projecting light upon a diluted pulp suspension which flows down with prescribed thickness and receiving the reflected light, and executing photoelectric conversion, biary coding, and arithmetic processing the binary coded signal. CONSTITUTION:The pulp suspension which is diluted in a vessel 1 to <=0.55wt% flows down from a tank 5 to a channel 6 while having a thickness of 1-6mm. Light 7 with a constant level is projected, its reflected light is received by a photodetector 8 composed of a CCD and a shift register in combination, and video information is sent to a signal processing part 9. If there are impurities in the video signal 10 whose part between A and B corresponds to one line, the signal level at the part is attenuated. The line number of a video signal lower than an expected slice signal, the number of binary-coded signals, and an address are stored 9 and a control part 12 calculates the size and number of impurities on the basis of those pieces of information 9 and displays the results on a display part 13. The impurities are detected by this method in a short time with high precision and the product loss is minimized.
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