Pilot operated pressure and vacuum relief valve

Claim 2

A RELIEF VALVE MECHANISM OF THE TYPE COMPRISING A BODY HAVING A CHAMBER THAT IS COMMUNICABLE WITH A FLUID SUPPLY LINE OR THE OTHER SOURCE OF FLUID AT HIGH PRESSURE, AN EXHAUST PASSAGE LEADING FROM SAID CHAMBER, A PILOT POPPET BIASED TO A CLOSED POSITION BLOCKING SAID EXHAUST PASSAGE BUT MOVABLE TO A CHAMBER VENTING POSITION IN CONSEQUENCE OF THE FORCE WHICH SUPPLY LINE FLUID IN SAID CHAMBER EXERTS THEREON WHENEVER ITS PRESSURE RISES TO A PREDETERMINED RELIEF VALUE, AND POPPET MECHANISM HAVING AN INNER SURFACE UPON WHICH PRESSURE FLUID IN SAID CHAMBER ACTS TO NORMALLY HOLD THE POPPET MECHANISM IN A CLOSED POSITION BLOCKING A RELIEF PATH BETWEEN SAID HIGH PRESSURE SUPPLY LINE AND A LOW PRESSURE RETURN LINE, AS LONG AS THE PILOT POPPET REMAINS IN ITS CLOSED POSITION, SAID POPPET MECHANISM HAVING AN OUTER SURFACE UPON WHICH SUPPLY LINE FLUID MAY ACT TO MOVE THE POPPET MECHANISM OUT OF SAID CLOSED POSITION WHENEVER THE PILOT POPPET IS OPENED AND FLUID IS FREE TO EXHAUST FROM SAID CHAMBER, SAID VALVE MECHANISM BEING CHARACTERIZED BY THE FOLLOWING FEATURES: A. MEANS IN THE POPPET MECHANISM PROVIDING A CONTROL PASSAGE TO SUBSTANTIALLY UNRESTRICTEDLY COMMUNICATE SAID CHAMBER WITH THE SUPPLY LINE; B. MEANS ON THE POPPET MECHANISM DEFINING A SURFACE UPON WHICH FLUID IN THE RETURN LINE MAY ACT TO EFFECT OPENING OF THE POPPET MECHANISM WHENEVER THE PRESSURE OF FLUID IN THE SUPPLY LINE AND THE CHAMBER WITH WHICH IT COMMUNICATES DROPS TO A VALUE BELOW THAT OF FLUID IN THE RETURN LINE, SO AS TO ALLOW FLUID TO FLOW FROM THE RETURN LINE TO THE SUPPLY LINE; C. AND FLOW RESTRICTING MEANS FOR SAID CONTROL PASSAGE COMPRISING COOPERATING ELEMENTS CARRIED BY THE POPPET MECHANISM AND THE PILOT POPPET AND RELATIVELY MOVABLE INTO PASSAGE RESTRICTING RELATION IN RESPONSE TO THE DROP IN CHAMBER PRESSURE THAT RESULTS FROM OPENING OF THE PILOT POPPET.

Claim 3

RELIEF VALVE MECHANISM WHICH OPENS WHEN FLUID PRESSURE IN A HIGH PRESSURE FLUID SUPPLY LINE DROPS TO A VALUE ONLY SLIGHTLY BELOW THAT OF FLUID IN A LOW PRESSURE FLUID RETURN LINE TO PREVENT FURTHER PRESSURE DROP IN THE SUPPLY LINE, COMPRISING: A. MEANS DEFINING A BODY HAVING (1) A SUPPLY PASSAGE PROVIDING A PART OF THE HIGH PRESSURE FLUID SUPPLY LINE, (2) A RETURN PASSAGE PROVIDING A PART OF THE LOW PRESSURE FLUID RETURN LINE, AND HAVING A PORTION WHICH IS ADJACENT TO A PORTION OF THE SUPPLY PASSAGE, (3) A BYPASS COMMUNICATING SAID ADJACENT PORTIONS OF THE SUPPLY AND RETURN PASSAGES, (4) AND AN ANNULAR VALVE SEAT IN SAID PORTION OF THE RETURN PASSAGE DEFINED BY A SURFACE ADJACENT TO THAT WALL THEREOF WHICH IS CLOSEST TO THE SUPPLY PASSAGE, SAID SEAT DEFINING SURFACE FACING AWAY FROM THE SUPPLY PASSAGE, BEING COAXIAL WITH THE BYPASS, AND SURROUNDING THE ADJACENT END THEREOF; B. A NORMALLY CLOSED HOLLOW RELIEF POPPET HAVING A TUBULAR REAR PORTION BY WHICH THE POPPET IS MOUNTED IN THE BODY, COAXIALLY OF AND OPPOSITE THE VALVE SEAT, FOR FORE AND AFT SLIDING MOTION TOWARD AND FROM A CLOSED FORWARD POSITION BLOCKING THE BYPASS, SAID RELIEF POPPET HAVING (1) A REDUCED FRONT PORTION WITH AN END SURFACE TO ENGAGE THE SEAT AND CLOSE THE BYPASS, AN INNER PORTION OF SAID END SURFACE THAT IS SURROUNDED BY THE SEAT BEING EXPOSED TO HIGH PRESSURE FLUID IN THE BYPASS WHICH THEREBY NORMALLY EXERTS FORCE ON THE POPPET TENDING TO MOVE IT REARWARDLY OFF ITS SEAT, (2) MEANS PROVIDING A SUBSTANTIALLY UNRESTRICTED CONTROL PASSAGE THROUGH SAID FRONT PORTION OF THE POPPET BY WHICH FLUID MAY BE FREELY TRANSFERRED BETWEEN THE SUPPLY PASSAGE AND THE HOLLOW INTERIOR OF THE POPPET. (3) AND REARWARDLY FACING SURFACES ON THE POPPET WHICH HAVE AN AREA LARGER THAN THAT OF SAID INNER PORTION OF THE POPPET END SURFACE; C. COOPERATING MEANS ON THE BODY AND ON THE POPPET PROVIDING A PRESSURE CHAMBER WHICH IS IN PART DEFINED BY SAID REARWARDLY FACING POPPET SURFACES, AND WHICH CHAMBER IS COMMUNICATED WITH THE SUPPLY PASSAGE THROUGH THE CONTROL PASSAGE SO THAT FLUID AT NORMALLY HIGH PRESSURE FILLS THE CHAMBER AND EXERTS FORCE ON SAID REARWARDLY FACING POPPET SURFACES TO HOLD THE POPPET CLOSED AGAINST THE OPENING FORCE WHICH FLUID AT THE SAME HIGH PRESSURE EXERTS ON SAID INNER PORTION OF THE POPPET END SURFACE, AND FROM WHICH CHAMBER FLUID CAN BE SUBSTANTIALLY UNRESTRICTEDLY EXPELLED THROUGH THE POPPET CONTROL PASSAGE TO THE SUPPLY PASSAGE IN CONSEQUENCE OF OPENING MOTION OF THE POPPET; D. ANNULAR SHOULDER MEANS ON THE EXTERIOR OF THE POPET LOCATED BETWEEN ITS TUBULAR REAR AND REDUCED FRONT PORTIONS, PROVIDING FORWARDLY FACING SURFACES UPON WHICH FLUID IN THE RETURN PASSAGE EXERTS FORCE TO OPEN THE POPPET WHENEVER THE PRESSURE OF FLUID IN THE SUPPLY PASSAGE, AND ACCORDINGLY IN THE PRESSURE CHAMBER, DROPS TO A VALUE SLIGHTLY LESS THAN THAT OF FLUID IN THE RETURN PASSAGE, AND BELOW WHICH VALVE A VOID TENDS TO FORM IN A CYLINDER SUPPLIED WITH FLUID FROM THE SUPPLY LINE WITH WHICH THE SUPPLY PASSAGE IN COMMUNICATED, SAID SEAT ENGAGING SURFACE OF THE POPPET MOVING REARWARDLY AWAY FROM SAID WALL OF THE RETURN PASSAGE DURING SUCH OPENING OF THE POPPET SO AS TO QUICKLY ESTABLISH A SUBSTANTIALLY UNRESTRICTED FLOW PATH ALONG WHICH A LARGE VOLUME OF FLUID CAN FLOW FROM THE RETURN PASSAGE TO THE SUPPLY PASSAGE VIA THE BYPASS FOR VOID PREVENTION, AND SUCH POPPET OPENING MOTION BEING SUBSTANTIALLY UNHINDERED BY CONCOMITANT EXPULSION OF FLUID FROM THE PRESSURE CHAMBER TO THE BYPASS TO THEREBY ASSURE FAST OPENING MOTION OF THE POPPET; E. AND SAID POPPET CONTROL PASSAGE COMPRISING A TUBULAR MEMBER THAT FORMS PART OF THE MECHANISM AND EXTENDS A DISTANCE FORWARDLY FROM SAID END SURFACE OF THE POPPET AND INTO THE BYPASS, SAID FORWARDLY EXTENDING TUBULAR MEMBER BEING SUBSTANTIALLY SMALLER IN OUTSIDE DIAMETER THAN THE BYPASS SO AS TO PRESENT LITTLE OBSTRUCTION TO BYPASS FLOW OF FLUID FROM THE RETURN PASSAGE TO THE SUPPLY PASSAGE, AND ASSURING AGAINST TURBULENCE THAT TENDS TO PRODUCE UNDESIRABLE PRESSURE BUILDUP AT A ZONE IMMEDIATELY AHEAD OF THE POPPET, DUE TO SAID BYPASS FLOW, THAT WOULD OTHERWISE CAUSE THE PRESSURE IN THE CHAMBER TO RISE ACCORDINGLY AND CREATE A TENDENCY FOR PREMATURE CLOSURE OF THE POPPET.

Claim 4

RELIEF VALVE MECHANISM WHICH OPENS WHEN FLUID PRESSURE IN A HIGH PRESSURE FLUID SUPPLY LINE DROPS TO A VALUE ONLY SLIGHTLY BELOW THAT OF FLUID IN A LOW PRESSURE FLUID RETURN LINE TO PREVENT FURTHER PRESSURE DROP IN THE SUPPLY LINE, COMPRISING: A. MEANS DEFINING A BODY HAVING (1) A SUPPLY PASSAGE PROVIDING A PART OF THE HIGH PRESSURE FLUID SUPPLY LINE, (2) A RETURN PASSAGE PROVIDING A PART OF THE LOW PRESSURE FLUID RETURN LINE, AND HAVING A PORTION WHICH IS ADJACENT TO A PORTION OF THE SUPPLY PASSAGE, (3) A BYPASS COMMUNICATING SAID ADJACENT PORTIONS OF THE SUPPLY AND RETURN PASSAGES, (4) AND AN ANNULAR VALVE SEAT IN SAID PORTION OF THE RETURN PASSAGE DEFINED BY A SURFACE ADJACENT TO THAT WALL THEREOF WHICH IS CLOSEST TO THE SUPPLY PASSAGE, SAID SEAT DEFINING SURFACE FACING AWAY FROM THE SUPPLY PASSAGE, BEING COAXIAL WITH THE BYPASS, AND SURROUNDING THE ADJACENT END THEREOF; B. A NORMALLY CLOSED HOLLOW RELIEF POPPET HAVING A TUBULAR REAR PORTION BY WHICH THE POPPET IS MOUNTED IN THE BODY, COAXIALLY OF AND OPPOSITE THE VALVE SEAT, FOR FORE AND AFT SLIDING MOTION TOWARD AND FROM A CLOSED FORWARD POSITION BLOCKING THE BYPASS, SAID RELIEF POPPET HAVING (1) A REDUCED FRONT PORTION WITH AN END SURFACE TO ENGAGE THE SEAT AND CLOSE THE BYPASS, AN INNER PORTION OF SAID END SURFACE THAT IS SURROUNDED BY THE SEAT BEING EXPOSED TO HIGH PRESSURE FLUID IN THE BYPASS WHICH THEREBY NORMALLY EXERTS FORCE ON THE POPPET TENDING TO MOVE IT REARWARDLY OFF ITS SEAT, (2) MEANS PROVIDING A SUBSTANTIALLY UNRESTRICTED CONTROL PASSAGE THROUGH SAID FRONT PORTION OF THE POPPET BY WHICH FLUID MAY BE FREELY TRANSFERRED BETWEEN THE SUPPLY PASSAGE AND THE HOLLOW INTERIOR OF THE POPPET. (3) AND REARWARDLY FACING SURFACES ON THE POPPET WHICH HAVE AN AREA LARGER THAN THAT OF SAID INNER PORTION OF THE POPPET END SURFACE; C. COOPERATING MEANS ON THE BODY AND ON THE POPPET PROVIDING A PRESSURE CHAMBER WHICH IS IN PART DEFINED BY SAID REARWARDLY FACING POPPET SURFACES, AND WHICH CHAMBER IS COMMUNICATED WITH THE SUPPLY PASSAGE THROUGH THE CONTROL PASSAGE SO THAT FLUID AT NORMALLY HIGH PRESSURE FILLS THE CHAMBER AND EXERTS FORCE ON SAID REARWARDLY FACING POPPET SURFACES TO HOLD THE POPPET CLOSED AGAINST THE OPENING FORCE WHICH FLUID AT THE SAME HIGH PRESSURE EXERTS ON SAID INNER PORTION OF THE POPPET END SURFACE, AND FROM WHICH CHAMBER FLUID CAN BE SUBSTANTIALLY UNRESTRICTEDLY EXPELLED THROUGH THE POPPET CONTROL PASSAGE TO THE SUPPLY PASSAGE IN CONSEQUENCE OF OPENING MOTION OF THE POPPET; D. ANNULAR SHOULDER MEANS ON THE EXTERIOR OF THE POPET LOCATED BETWEEN ITS TUBULAR REAR AND REDUCED FRONT PORTIONS, PROVIDING FORWARDLY FACING SURFACES UPON WHICH FLUID IN THE RETURN PASSAGE EXERTS FORCE TO OPEN THE POPPET WHENEVER THE PRESSURE OF FLUID IN THE SUPPLY PASSAGE, AND ACCORDINGLY IN THE PRESSURE CHAMBER, DROPS TO A VALUE SLIGHTLY LESS THAN THAT OF FLUID IN THE RETURN PASSAGE, AND BELOW WHICH VALVE A VOID TENDS TO FORM IN A CYLINDER SUPPLIED WITH FLUID FROM THE SUPPLY LINE WITH WHICH THE SUPPLY PASSAGE IN COMMUNICATED, SAID SEAT ENGAGING SURFACE OF THE POPPET MOVING REARWARDLY AWAY FROM SAID WALL OF THE RETURN PASSAGE DURING SUCH OPENING OF THE POPPET SO AS TO QUICKLY ESTABLISH A SUBSTANTIALLY UNRESTRICTED FLOW PATH ALONG WHICH A LARGE VOLUME OF FLUID CAN FLOW FROM THE RETURN PASSAGE TO THE SUPPLY PASSAGE VIA THE BYPASS FOR VOID PREVENTION, AND SUCH POPPET OPENING MOTION BEING SUBSTANTIALLY UNHINDERED BY CONCOMITANT EXPULSION OF FLUID FROM THE PRESSURE CHAMBER TO THE BYPASS TO THEREBY ASSURE FAST OPENING MOTION OF THE POPPET; E. AND SAID POPPET CONTROL PASSAGE COMPRISING A TUBULAR MEMBER THAT FORMS PART OF THE MECHANISM AND EXTENDS A DISTANCE FORWARDLY FROM SAID END SURFACE OF THE POPPET AND INTO THE BYPASS, SAID FORWARDLY EXTENDING TUBULAR MEMBER BEING SUBSTANTIALLY SMALLER IN OUTSIDE DIAMETER THAN THE BYPASS SO AS TO PRESENT LITTLE OBSTRUCTION TO BYPASS FLOW OF FLUID FROM THE RETURN PASSAGE TO THE SUPPLY PASSAGE, AND ASSURING AGAINST TURBULENCE THAT TENDS TO PRODUCE UNDESIRABLE PRESSURE BUILDUP AT A ZONE IMMEDIATELY AHEAD OF THE POPPET, DUE TO SAID BYPASS FLOW, THAT WOULD OTHERWISE CAUSE THE PRESSURE IN THE CHAMBER TO RISE ACCORDINGLY AND CREATE A TENDENCY FOR PREMATURE CLOSURE OF THE POPPET.