Automatic control system for single tank sand filter

Claim 1

A FIALTERING SYSTEM, COMPRISING: A CLOSE FILTER TANK FOR RECEIVING AND MAINTAINING LIQUID UNDER HYDRAULIC PRESSURE HAVING AN INLET END AND AN OUTLET END; A SUPPLY CONDUIT FOR SUPPLYING A LIQUID UNDER PRESSURE TO BE FILTERED CONNECTED WITH SAID INLET; A SUPPLY VALVE CONNECTED IN SAID SUPPLY CONDUIT CONTROLLING THE FLOW OF LIQUID TO SAID INLET; A SERVICE CONDUIT FOR FILTERED LIQUID UNDER TANK PRESSURE CONNECTED WITH SAID OUTLET; A SERVICE FLOW CONTROL VALVE CONNECTED IN SAID SERVICE CONDUIT; A WASTE CONDUIT CONNECTED WITH SAID INLET; A WASTE VALVE CONNECTED IN SAID WASTE CONDUIT; A BACKWASH CONDUIT CONNECTED AT ONE END THEREOF WITH SAID SUPPLY CONDUIT CONNECTED AT SAID SUPPLY CONTROL VALVE AND CONNECTED AT ITS OPPOSITE END WITH SAIDA OUTLET UPSTREAM OF SAID SERVICE VALVE; A BACKWASH VALVE CONNECTED IN SAID BACKWASH CONDUIT UPSTREAM OF THE POINT OF CONNECTION OF SAID BACKWASH CONDUIT WITH SAID OUTLET; A DRAIN CONDUIT CONNECTED AT ONE END WITH SAID OUTLET AT A POINT BETWEEN SAID BACKWASH AND SERVICE VALVE, SAID DRAIN CONDUIT BEING CONNECTED AT ITS OTHER END WITH SAID WASTE CONDUIT BEING CONNECTED AT WASTE VALVE; A DRAIN VALVE CONNECTED IN SAID DRAIN CONDUIT UPSTEAM OF ITS POINT OF CONNECTION WITH SAID WASE CONDUIT; AND ROTARY MEANS CONSTRUCTED AND ARRANGED TO MOVE THROUGH A PREDETERMINED SEQUENCE OF POSITIONS FOR OPERATINGA AND DIRECTLY CONTROLLING ALL OF SAID VALVES, TO (1) CLOSE ALL VALVES WHEN IN A FIRST SEQUENCEPOSITION; (2) CLOSE THE SUPPLY, SERVICE, AND DRAIN VALVES AND OPEN THE BACKWASHING AND WASTE VALVE TO EFFECT A BACK WASHING OR REVERSE FLOW OF UNFILTERED LIQUID THROUGH THE FILTER TANK AND DISCHARGE THROUGH THE WASTE CONDUIT WHEN IN A SECOND SEQUENCE POSITION; (3) CLOSE ALL VALVES WHEN IN A THIRD SEQUENCE POSITION; (4) OPEN THE SUPPLY AND DRAIN VALVES AND CLOSE ALL OF THE OTHER VALVES TO EFFECT A RINSE FLOW THROUGH THE SUPPLY CONDUIT, FILTER TANK, DRAIN CONDUIT AND WASTE CONDUIT WHEN IN A FOURTH SEQUENCE POSITION; (5) OPEN THE SUPPLY VALVE AND CLOSE THE OTHER VALVES TO PRESSURIZE THE FILTER TANK WHEN IN A FIFTH SEQUENCE POSITION; AND (6) OPEN THE SUPPLY AND SERVICE VALVES AND CLOSE ALL OF THE OTHER VALVES TO EFFECT A FLOW THROUGH THE SUPPLY CONDUIT, FILTER TANK AND SERVICE CONDUIT WHEN IN A SIXTH SEQUENCE POSITION.