Filter system assembly

Claim 1

A FILTER SYSTEM ASSEMBLY CONSTRUCTION COMPRISING, A FIRST AND SECOND TANK ASSEMBLY EACH INCLUDING A TANK HAVING A MANHOLE TYPE OPENING THEREIN, EACH TANK HAVING A FALSE BOTTOM ADAPTED TO SUPPORT FILTER MATERIAL WHILE PERMITTING LIQUID FLOW THEREBY, AND EACH TANK HAVING A PIPE IN SAID TANK EXTENDING FROM A POINT BELOW SAID FALSE BOTTOM TO A POINT IN PROXIMITY TO THE MANHOLE TYPE OPENING IN SAID TANK AND SUPPORTED THEREIN, AND FILTER MATERIAL IN EACH SAID TANK; A SINGLE PUMP-VALVE UNIT ASSEMBLY SUPPORTED ON SAID FIRST TANK ACROSS SAID OPENING TO FORM WITH SAID FIRST TANK ASSEMBLY A FILTER SYSTEM ASSEMBLY; SAID PUMP-VALVE UNIT ASSEMBLY HAVING A FIRST PASSAGEWAY TO INTRODUCE LIQUID TO BE FILTERED, INTO THE FILTER SYSTEM ASSEMBLY A SECOND PASSAGEWAY TO DISCHARGE FILTERED LIQUID OUT OF SAID FILTER SYSTEM ASSEMBLY, AND A THIRD PASSAGEWAY TO DISCHARGE BACKWASH WASTE WATER OUT OF SAID FILTER SYSTEM ASSEMBLY; MEANS COUPLING SAID SECOND TANK ASSEMBLY TO SAID PUMP-VALVE UNIT ASSEMBLY IN PARALLEL FLOW CONNECTION TO SAID FIRST TANK ASSEMBLY FOR SIMULTANEOUS COOPERATION WITH SAID PUMP-VALVE UNIT ASSEMBLY IN FILTERING LIQUID ENTERING SAID PUMP-VALVE ASSEMBLY; AND MEANS FOR SELECTIVELY DISCONNECTING EITHER OF SAID TANK ASSEMBLIES FROM SAID SYSTEM ASSEMBLY TO ENABLE BACK WASHING OF EACH TANK ASSEMBLY INDEPENDENTLY OF THE OTHER.