Switching valve for continuous filtering devices

Claim 1

A FLOW CONTROL UNIT FOR SELECTIVELY CONTROLLING FLUID FLOW FROM A COMMON INLET CONDUIT THROUGH TWO LOOP-SHAPED FLOW PATHS INTO A COMMON OUTLET CONDUIT COMPRISING A VALVE HOUSING HAVING AT ONE SECTION THEREOF A SUPPLY INLET PORT CONNECTED TO SAID COMMON INLET CONDUIT AND TWO LOOP INLET PORTS ARRANGED IN GENERALLY REGULARLY ANGULARLY SPACED RELATION ABOUT THE AXIS OF SAID HOUSING, SAID LOOP INLET PORTS HAVING SUBSTANTIALLY EQUAL CROSS-SECTIONAL AREAS, AND A VALVE MEMBER ROTATABLE WITHIN SAID HOUSING ABOUT SAID AXIS, SAID MEMBER HAVING AT ONE SECTION THEREOF A MAIN FEED PASSAGE EXTENDING THERETHROUGH FOR CONTINUOUS COMMUNICATION WITH SAID COMMON INLET CONDUIT AND DEFINING BETWEEN SAID PASSAGE ENDS A WALL SECTION LARGER IN ANGULAR EXTENT THAT EITHER OF SAID LOOP INLET PORTS WHEREBY UPON ROTATION OF SAID VALVE MEMBERS EITHER OF SAID PORTS CAN BE EXCLUSIVELY IN COMMUNICATION WITH SAID FEED PASSAGE AND THE OTHER CLOSED BY SAID WALL SECTION OR BOTH SAID PORTS PARTIALLY IN COMMUNICATION THEREWITH, AND SAID VALVE MEMBER ALSO HAVING TWO SUBSTANTIALLY SYMMETRICALLY ARRANGED BLEED PASSAGES EXTENDING FROM SAID FEED PASSAGE THROUGH SAID WALL SECTION AT LOCI SPACED RESPECTIVELY FROM THE CORRESPONDING ENDS OF SAID WALL SECTION PERIPHERY AND OF SAID FEED PASSAGE AND FROM EACH OTHER TO MAINTAIN FLOW CONTINUITY DURING ROTATION OF SAID VALVE MEMBER, SAID VALVE HOUSING HAVING AT A SECOND AXIALLY SPACED SECTION A SUPPLY DISCHARGE PORTS CONNECTED TO SAID OUTLET CONDUIT AND TWO LOOP DISCHARGE PORTS ARRANGED IN GENERALLY REGULARLY SPACED RELATION ABOUT THE AXIS OF SAID HOUSING, SAID LOOP OUTLET PORTS HAVING SUBSTANTIALLY EQUAL CROSS-SECTIONAL AREAS, SAID VALVE MEMBER HAVING AT A SECOND SECTION THEREOF A DISCHARGE PASSAGE EXTENDING THERETHROUGH FOR ESTABLISHING UPON ROTATION OF SAID VALVE MEMBER INTERCOMMUNICATION BETWEEN SAID SUPPLY DISCHARGE PORT AND SAID LOOP DISCHARGE PORTS ALTERNATIVELY OR BOTH SAID LOOP DISCHARGE PORTS PARTIALLY IN CORRESPONDENCE WITH SAID INLET PORTS, AND SAID VALVE MEMBER ALSO HAVING A VENT PASSAGE EXTENDING FROM A LOCUS ON THE VALVE MEMBER PERIPHERY GENERALLY INTERMEDIATE THE ENDS OF SAID DISHCARGE PASSAGE TO THE OUTSIDE ATMOSPHERE FOR VENTING THE LOOP DISCHARGE PORT NOT IS COMMUNICATION WITH SAID SUPPLY DISCHARGE PORT.