Surge damping valve

Claim 1

A SURGE DAMPING VALVE COMPRISING, A BODY HAVING A BORE, AN INLET ENTERING SAID BORE AT ONE END THEREOF AND AN OUTLET EXTENDING LATERALLY FROM SAID BORE, A SLEEVE FITTED IN SAID BORE, SAID SLEEVE BEING PROVIDED WITH A PLURALITY OF AXIALLY SPACED PORTS THROUGH WHICH FLUID CAN FLOW FROM SAID INLET TO SAID OUTLET, THE PORTS WHICH ARE NEAREST TO THE INLET BEING SMALL IN SIZE AND PERMITTING ONLY RESTRICTED FLOW THROUGH THEM, THE PORTS FARTHER FROM SAID INLET BEING LARGE ENOUGH TO PERMIT UNRESTRICTED FLOW, A PISTON SLIDABLY FITTED IN SAID SLEEVE FOR CLOSING AND OPENING SAID PORTS, PRESSURE AT SAID INLET ACTING ON AN ENDWISE PORTION OF SAID PISTON AND TENDING TO MOVE SAID PISTON IN A DIRECTION OPENING SAID PORTS, A FLUID RETAINING CHAMBER BEING DEFINED ABOVE SAID PISTON IN SAID SLEEVE THE PRESSURE OF FLUID IN WHICH TENDS TO PREVENT SAID PISTON FROM OPENING SAID PORTS, MEANS RESILIENTLY BIASING SAID PISTON TOWARD SAID INLET, AND CONTROL MEANS FOR CONTROLLING THE RATE AT WHICH SAID PISTON OPENS SAID PORTS IN RESPONSE TO AN INCREASE IN PRESSURE AT SAID INLET, SAID CONTROL MEANS BEING CONTAINED IN A CAP WHICH IS MOUNTED TO SAID BODY AT THE END OF SAID BORE WHICH IS OPPOSITE TO SAID INLET, SAID CONTROL MEANS COMPRISING, A FLUID PASSAGEWAY IN SAID CAP COMMUNICATING BETWEEN SAID CHAMBER AND SAID OUTLET, MEANS FORMING A SEAT IN SAID PASSAGEWAY, A VALVE ELEMENT MOVABLE WITH RESPECT TO SAID SEAT AND FORMING A VALVE WITH SAID SEAT FOR CONTROLLING THE FLOW OF FLUID IN SAID PASSAGEWAY FROM SAID CHAMBER TO SAID OUTLET, MEANS RESILIENTLY URGING SAID VALVE ELEMENT AWAY FROM SAID SEAT, PRESSURE DIFFERENTIALLY OPERATED MEANS FOR MOVING SAID VALVE ELEMENT INTO CLOSING RELATION WITH SAID SEAT IN RESPONSE TO A PRESSURE INCREASE IN SAID CHAMBER, SAID PRESSURE DIFFERENTIALLY OPERATED MEANS BEING SLIDABLY RECEIVED IN SAID PASSAGEWAY BETWEEN SAID CHAMBER AND SAID VALVE ELEMENT AND HAVING A RESTRICTED ORIFICE FORMED THROUGH IT, AND MEANS FORMING A RESILIENT ABUTTING CONNECTION BETWEEN SAID VALVE ELEMENT AND SAID PRESSURE DIFFERENTIALLY OPERATED MEANS, WHEREBY IN RESPONSE TO SUDDEN OPENING MOVEMENT OF SAID PISTON SAID PRESSURE DIFFERENTIALLY OPERATED MEANS MOVES SAID VALVE ELEMENT INTO RESILIENT CLOSING CONTACT WITH SAID SEAT TO RESTRICT FLOW FROM SAID CHAMBER TO SAID OUTLET AND THEREBY PERMITS SAID PISTON TO OPEN SAID PORTS ONLY GRADUALLY.