Float-operated surge relief shutoff valve

Claim 1

IN A VALVE BODY: (A) AN INLET; (B) AN OUTLET; (C) A FLOW PASSAGE BETWEEN SAID INLET AND OUTLET; (D) A VALVE SEAT; (E) A PRESSURE RESPONSIVE VALVE CHAMBER; (F) A MAIN PISTON VALVE SEALINGLY ENGAGED AND SLIDABLE WITHIN SAID CHAMBER AND BIASED TO BE POSITIONED ON SAID SEAT TO CLOSE SAID VALVE ACROSS SAID FLOW PASSAGE; (G) A NORMALLY CLOSED RELIEF VALVE ON SAID BODY; (H) A RELIEF VALVE PISTON CONNECTED TO OPEN SAID RELIEF VALVE AT A PREDETERMINED PRESSURE; (I) PASSAGE MEANS WITHIN SAID BODY TO PROVIDE A TOTAL PRESSURE PICKUP EXTENDING THROUGH SAID PISTON VALVE AND SAID CHAMBER TO DIRECTLY COMMUNICATE SUBSTANTIAL TOTAL PRESSURE AT SAID INLET EXTERNALLY OF SAID SEAT WHEN SAID INLET IS CLOSED AND INTERNALLY OF SAID SEAT WHEN SAID INLET IS OPEN TO ACT UPON SAID RELIEF VALVE PISTON AND OPEN SAID RELIEF VALVE AT SAID PREDETERMINED PRESSURE; (J) MEANS WITHIN SAID MAIN PISTON TO COMMUNICATE PRESSURE ADJACENT SAID INLET TO SAID CHAMBER; (K) MEANS CONNECTED TO SAID BODY TO SEAL SAID LAST PRESSURE WITHIN SAID CHAMBER; (L) MEANS WITHIN SAID CHAMBER TO BE ACTED UPON BY SAID LAST PRESSURE TO HOLD SAID MAIN PISTON IN SAID CLOSED POSITION ON SAID SEAT AGAINST PRESSURE IN SAID INLET WHEN SAID CHAMBER IS SEALED; (M) AND MEANS WITHIN SAID BODY TO CONNECT SAID PRESSURE IN SAID CHAMBER TO SAID RELIEF VALVE SO THAT WHEN SAID RELIEF VALVE IS OPENED SAID CHAMBER PRESSURE IS RELEASED, SEAL MEANS BETWEEN SAID RELIEF VALVE AND SAID RELIEF VALVE PISTON, SAID PASSAGE MEANS BELVE ING INDEPENDENT OF THE PRESSURE WITHIN SAID CHAMBER.