Importance

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Abstract

Apparatus for inspecting pulp or similar material arranged to flow in a sheet 10 past an inspection station, comprising a row of photosensitive devices 14 arranged to receive light reflected from or transmitted through the material, circuit means 30 receiving the output signals from the photosensitive devices and providing a defect signal when an inclusion in the pulp passes the inspection station, and integrating circuitry 32 adapted to integrate the defect signal with respect to time thereby to measure the total equivalent black area of the sheet 10. To allow for integration over a long travel of the sheet, the integrating circuitry includes an integrator 32, and a pulse generator 34 adapted to receive the output of the integrator and to generate an output pulse when the result of the integration reaches a predetermined magnitude. The integrator is reset to zero on the occurrence of each said pulse, and a counter 36 is arranged to count the pulses generated by the pulse generator.

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First Claim