Gravity filter

Claim 1

IN A GRAVITY FILTER INCLUDING A FILTER VESSEL, A STATIONARY CYLINDRICAL FILTER BED OF FINELY DIVIDED SOLID MATERIAL, THE IMPROVEMENT WHICH COMPRISES IN COMBINATION A FLOW RATE DETECTOR ADAPTED TO DETERMINE THE OCCURRENCE OF A PLUGGING CONDITION WITHIN THE FILTER BED, AN INLET CONDUIT LEADING INTO SAID VESSEL ABOVE SAID FILTER BED, AN OUTLET CONDUIT LEADING FROM SAID VESSEL AT A REGION BELOW SAID FILTER BED, A SCRAPING MEMBER MOVABLY DISPOSED WITHIN SAID VESSEL, A SHAFT ATTACHED TO SAID SCRAPING MEMBER AND PIERCING SAID VESSEL, SEALING MEANS FOR MAINTAINING SAID SHAFT AND SAID VESSEL IN A FLUID-TIGHT MOVABLE RELATIONSHIP, A DRIVING MECHANISM, CONTROLLER MEANS RESPONSIVE TO SAID FLOW RATE DETECTOR, MEANS ACTUATED BY SAID CONTROLLER MEANS FOR ACTUATING SAID DRIVING MECHANISM, SAID DRIVING MECHANISM BEING CONNECTED WITH SAID SHAFT SO AS TO IMPART A LONGITUDINAL AND ROTATIONAL MOVEMENT TO SAID SHAFT WHEREBY SAID SCRAPING MEMBER ENGAGES AND BREAKS UP PLUGGED PORTIONS OF SAID FILTER BED INTO FINE PARTICLES AND CAUSES SAID PARTICLES TO BE SUSPENDED IN THE LIQUID WITHIN SAID FILTER VESSEL AND MEANS FOR WITH DRAWING THE RESULTING LIQUID SUSPENSION FROM SAID FILTER VESSEL.