FILTER FOR WASTE WATER

PURPOSE:To enhance the rate of removal of suspension substances by providing a plurality of reverse cone-shaped screens in a row vertically with a space between each of the screens and also providing back wash nozzles, one for each of screens in the way of revolving relatively in the cylindrical enclosed casing. CONSTITUTION:The waste water is guided from the inlet 2 into the casing 1 and led from the opening 12a to the bottom side of screen 11. Next, the waste water passes through the screen 11a and flows into the enclosed chamber 13'. Further, the same passes through the interconnecting tube 14 and is guided into the enclosed chamber 13' on the uppermost side to be drained out of the outlet 3. When a certain quantity of suspensions are caught on the screen 11a, washing water is charged into from the supply tube 10. Then the drive unit 5 is started to revolve the center tube 4, the inlet tube 8 and each of the nozzles 9 along with the upper face of screen 11 all at once. Washing water is injected out of each of nozzles 11 to remove the suspensions caught on the screen.