Pressure-responsive fluid flow control valve

Claim 1

A PRESSURE-RESPONSIVE HYDRAULIC PRESSURE FLUID FLOW CONTROL VALVE, COMPRISING A CASING STRUCTURE, A VALVE BODY MOUNTED IN SAID CASING STRUCTURE AND SEPARATING SAID CASING STRUCTURE INTO AN UPSTREAM FLUID INLET CHAMBER OF NORMALLY HIGHER FLUID PRESSURE AND A DOWNSTREAM FLUID OUTLET CHAMBER OF NORMALLY LOWER FLUID PRESSURE, SAID VALVE BODY HAVING A FLUID PASSAGEWAY EXTENDING THERETHROUGH FROM SAID INLET CHAMBER TO SAID OUTLET CHAMBER AND CONTAINING A VALVE SEAT, SAID VALVE BODY HAVING A VALVE BORE COMMUNICATING WITH SAID FLUID PASSAGEWAY AND A SPRING CHAMBER COMMUNICATING WITH SAID VALVE BORE, MEANS COMPLETELY SEALING OFF SAID SPRING CHAMBER FROM COMMUNICATION WITH SAID FLUID OUTLET CHAMBER, A VALVE PLUNGER MOUNTED IN SAID VALVE BORE FOR MOTION INTO AND OUT OF ENGAGEMENT WITH SAID VALVE SEAT AND TERMINATING WITHIN SAID SPRING CHAMBER, SAID VALVE PLUNGER HAVING A PISTON AREA THEREON COMMUNICATING WITH SAID INLET CHAMBER THROUGH SAID PASSAGEWAY, AN ANNULAR HYDRAULIC PRESSURE-FLUID-TIGHT SEALING MEMBER ENCIRCLING SAID VALVE PLUNGER IN TIGHT SEALING ENGAGEMENT WITH SAID VALVE PLUNGER AND THE WALL OF SAID VALVE BORE, AND SPRING MEANS IN SAID SPRING CHAMBER ENGAGING AND RESILIENTLY URGING SAID VALVE PLUNGER INTO YIELDING PRESSURERESPONSIVE ENGAGEMENT WITH SAID VALVE SEAT.