DETECTING METHOD OF BOUNDARY SURFACE OF SLUDGE IN SETTLING CHAMBER

PURPOSE:To measure the boundary surface of sludge accurately from variation in the electric resistance of the liquid in a settling chamber by applying a voltage between a couple of electrodes and moving up and down an electrode sensor which measures the electric resistance of the liquid in the chamber. CONSTITUTION:Sludge water 11 is supplied to the settling chamber 10 and the boundary surface 15 of the sludge 12 separated by settlement should be held at a specific water level. The voltage is applied between a couple of electrodes 18 of a detector 17 to measure the electric resistance in the liquid in the chamber, and its output signal is sent to a central processor 23 through an indicator 21. The electrode sensor suspended by a cable 24 is moved up and down by a servomotor 25 to which a drum 26 and a tachometer are connected to measure the distance from the water surface. Abrupt signal variation inputted to the central processor 25 is regarded as the boundary surface of the sludge and an operation command is sent to the pump 14 to hold the boundary surface. Thus, the sludge boundary surface 15 is measured speedily and accurately by the simple constitution.