JPS5658506A - Waste sludge control method - Google Patents

Abstract

PURPOSE: To determine the proper timings of precipitate discharging by calculating the amount of deposition of precipitate from the flow rate and turbidity taking the time delay on the inflow side and outflow side into account.

CONSTITUTION: The outputs of flow rate and turbidity detectors 2, 3 go via respective converters 4, 5 into a multiplier 6, by which an inflow suspension amount is calculated. On the other hand, an output suspension amount is calculated in the same manner. The output of the multiplier 6 is inputted via an AND gate 17 at the timing of a clock device 16 into a writing circuit 18, by which it is written into a register 19-1. A time delay circuit 20 delays the timing of the device 16 and applies said output into a shifting circuit 21. The information of a register 19-n is read out by a readout circuit 22 and is inputted to a subtractor 25 at the timing of the device 16 in the same manner as for the output of the multiplier 15. In the subtractor 25, a precipitate amount is calculated and is applied to an integrator 26, by which it is integrated as a deposition amount. The output of the integrator 26 is compared with a set value 28 in a comparator 27, and when the deposition amount reaches the set value, a scraper 8 is operated by way of a drive unit 29, and a discharge valve 31 is opened.

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