Flow control valve

Claim 1

A SEALING JOINT HAVING A SURFACE INTERSECTED BY A PASSAGE, A SPINDLE MEMBER HAVING A HEAD ORTION AND BEING MOVABLE AXIALLY INTO AND OUT OF SAID PASSAGE, SAID SPINDLE RECESS AXIALLY INWARDLY OF SAID HEAD PORAN ANNULAR RECESS AXIALLY INWARDLY OF SAID HEAD PORTION, A RING-SHAPED VOLUME OF HIGHLY VISCOUS, FLOWABLE, COMPRESSIBLE MATERIAL FILLING ALL OF SAID RECESS AND IN SUFFICIENT EXCESS TO PROJECT RADIALLY OUTWARDLY OF SAID RECESS, SAID HEAD PORTION HAVING A RADIAL SHOULDER AT ONE END OF SAID RECESS, A SLEEVE ENCAPSULATING AND FILLED BY SAID RING-SHAPED VOLUME AND INCLUDING A WALL FORMING A CYLINDER FOR SAID RING-SHAPED VOLUME, AND AN END WALL EXTENDING RADIALLY INWARDLY TO A SMALLER DIAMETER CYLINDRICAL BORE, SAID BORE AND SAID HEAD PORTION HAVING CONFRONTING AXIALLY EXTENDING CONCENTRIC SURFACES SIZED TO HAVE A SLIDING FIT WITH ONE ANOTHER, WHEREBY SAID RING-SHAPED VOLUME IS PROTECTED AGAINST EROSION BY ANY FLUIDS FLOWING THROUGH SAID PASSAGE, SAID BORE TERMINATING IN A FLAT RADIAL END FACE ON SAID SLEEVE OVERLYING AND ENGAGEABLE WITH SAID SURFACE, AND SHOULDER MEANS ON SAID SPINDLE MEMBER FORMING A PISTON HEAD OVERLYING SAID RING-SHAPED VOLUME AND HAVING AN EFFECTIVE AREA GREATER THAN THE CORRESPONDING OPPOSITELY DISPOSED RADIAL SHOULDER, SAID PISTON HEAD BEING RELATIVELY MOVABLE AXIALLY AFTER SAID END FACE ENGAGES SAID SURFACE TO COMPRESS SAID RING-SHAPED VOLUME, THEREBY SEPARATING SAID AXIALLY EXTENDING CONFRONTING SURFACES WHILE TRANSLATING SAID SPINDLE MEMBER INTO SAID PASSAGE, THE COMPRESSION OF SAID RING-SHAPED VOLUME BUILDING UP CONTACT PRESSURE BETWEEN SAID END FACE AND SAID SURFACE AND CARRYING SAID RING-SHAPED VOLUME INTO SAID PASSAGE.