Control valve

Claim 1

A VALVE COMPRISING A HOUSING HAVING AN INLET PORT, AN OUTLET PORT, A RETURN PORT AND AN EXHAUST PORT, A VALVE MEMBER MOVABLE IN SAID HOUSING AND SEALING SAID OUTLET AND RETURN PORTS WHEN IN A NEUTRAL POSITION, A FIRST PAIR OF PASSAGES IN SAID VALVE MEMBER, A SECOND PAIR OF PASSAGES IN SAID VALVE MEMBER, SAID VALVE MEMBER BEING MOVABLE FROM SAID NEUTRAL POSITION TO A FIRST POSITION FOR CONNECTING SAID FIRST PAIR OF PASSAGES TO SAID OUTLET AND RETURN PORTS FOR OPENING A FLOW PASSAGE FROM SAID INLET TO SAID OUTLET PORT AND FROM SAID RETURN PORT TO SAID EXHAUST PORT, SAID VALVE MEMBER ALSO BEING MOVABLE TO A SECOND POSITION FOR CONNECTING SAID SECOND PAIR OF PASSAGES TO SAID OUTLET AND RETURN PORTS FOR REVERSING THE FLOW THROUGH SAID OUTLET AND RETURN PORTS, SAID HOUSING HAVING A CYLINDRICAL CHAMBER THEREIN, SAID VALVE MEMBER BEING CYLINDRICAL AND ROTATABLE WITHIN SAID CHAMBER, SAID INLET AND EXHAUST PORTS BEING IN OPPOSITE SIDES OF THE CYLINDRICAL WALL OF SAID HOUSING AND SAID OUTLET AND RETURN PORTS BEING IN DIAMETRICALLY OPPOSITE SIDES OF AN END WALL OF SAID CYLINDRICAL CHAMBER, SAID VALVE MEMBER HAVING SEMI-CIRCULAR SLOTS IN OPPOSITE SIDES THEREOF FOR COMMUNICATION WITH SAID INLET AND EXHAUST PORTS AND SAID FIRST AND SECOND PAIRS OF PASSAGES EACH COMPRISING TWO DIAMETRICALLY OPPOSED BORES EACH COMMUNICATING WITH ONE OF SAID SLOTS, SAID PAIRS OF PASSAGES EXTENDING UPWARDLY FROM SAID SLOTS, SAID CYLINDRICAL VALVE MEMBER BEING SPACED AT ITS LOWER END FROM AN END OF SAID HOUSING TO FORM A CHAMBER, PORTS EXTENDING DOWNWARDLY FROM SAID SLOTS TO SAID CHAMBER FOR ADMITTING PRESSURE THERETO FROM SAID INLET PORT WHEREBY THE VALVE MEMBER WILL BE URGED UPWARDLY INTO SEALING ENGAGEMENT WITH AN UPPER END OF SAID HOUSING.