Pressure relief or blowdown valve

Claim 2

AS A SUB-COMBINATION IN A PILOT VALVE ASSEMBLY, A VALVE SEAT AND VALVE ELEMENT COMPRISING, A TUBULAR SEAT MEMBER HAVING AN AXIAL BORE AND HAVING THE UPPER PORTION OF ITS EXTERIOR SURFACE FLARED OUTWARDLY AT A PREDETERMINED ANGLE RELATIVE TO ITS AXIS, A SOLID VALVE ELEMENT BODY HAVING AN ANNULAR DEPENDING SKIRT WHICH ENCIRCLES THE FLARED PORTION OF THE TUBULAR SEAT MEMBER, THE INNER ANNULAR SURFACE OF SAID SKIRT BEING INCLINED INWARDLY TOWARD ITS LOWER END, WITH ITS ANGLE OF INCLINATION RELATIVE TO THE AXIS OF THE BODY AND OF THE SEAT MEMBER BEING GREATER THAN THE ANGLE OF INCLINATION OF THE FLARED PORTION OF SAID MEMBER, WHEREBY AS THE BODY MOVES UPWARDLY RELATIVE TO THE SEAT, THE AREA OF THE ANNULAR SPACE BETWEEN THE SKIRT AND SEAT MEMBER DECREASES, AND A VALVE SEATING ELEMENT MOUNTED IN THE CENTRAL PORTION OF THE VALVE ELEMENT BODY AND ENGAGEABLE WITH THE UPPER END OF THE TUBULAR SEAT MEMBER TO CLOSE THE BORE THROUGH SAID MEMBER.

Claim 3

A SAFETY RELIEF VALVE DEVICE FOR CONTROLLING THE PRESSURE WITHIN A CONTROLLED AREA INCLUDING, A MAIN VALVE MEMBER HAVING ONE SIDE COMMUNICATING WITH SAID CONTROLLED AREA FOR RELIEVING THE PRESSURE THEREIN WHEN SAID MEMBER IS IN AN OPEN POSITION, A HOUSING HAVING A CHAMBER IN COMMUNICATION WITH THE SECOND SIDE OF THE VALVE MEMBER, MEANS FOR CONDUCTING THE PRESSURE WITHIN THE CONTROLLED AREA TO THE CHAMBER, WHEREBY SAID SECOND SIDE IS EXPOSED TO SAID PRESSURE IN ALL POSITIONS OF SAID MAIN VALVE MEMBER, EQUALIZATION OF PRESSURES A CROSS VALVE MEMBER MAINTAINING SAID MEMBER IN THE CLOSED POSITION AND UNEQUALIZATION OF PRESSURES ACROSS SAID MEMBER MAINTAINING SAID MEMBER IN THE OPEN POSITION, A PILOT VALVE ASSEMBLY INCLUDING A PILOT VALVE ELEMENT MOVABLE WITH RESPECT TO A PILOT VALVE SEAT AND EXPOSED TO THE PRESSURE IN SAID CHAMBER, SAID PILOT VALVE ELEMENT VENTING THER PRESSURE FROM THE CHAMBER WHEN SAID PILOT VALVE ELEMENT IS IN AN OPEN POSITION TO UNEQUALIZE THE PRESSURES ACROSS SAID MAIN VALVE MEMBER AND THEREBY OPEN THE SAME TO RELIEVE THE PRESSURE FROM SAID CONTROLLED AREA, SAID PILOT VALVE ELEMENT BEING RESPONSIVE TO THE PRESSURE IN SAID CHAMBER AND BEING OPENED WHEN SAID PRESSURE REACHES A PRESELECTED PRESSURE AND BEING CLOSED WHEN SAID PRESSURE REDUCES TO A SECOND PRESELECTED PRESSURE, COACTING SURFACES FORMING PART OF SAID PILOT VALVE ASSEMBLY DEFINING A DISCHARGE ORIFICE THROUGH SAID PILOT VALVE ASSEMBLY DOWNSTREAM OF THE PILOT VALVE SEAT AND FORMING A SPACE BETWEEN SAID SEAT AND THE DISCHARGE ORIFICE, ONE OF SAID COACTING SURFACES BEING MOVABLE RELATIVE TO THE OTHER WITH THE PILOT VALVE ELEMENT, SAID COACTING SURFACES BEING TAPERED RELATIVE TO EACH OTHER SO THAT AS THE PILOT VALVE ELEMENT MOVES FROM FULLY OPENED POSITION TO CLOSED POSITION THE EFFECTIVE AREA OF THE ORIFICE IS INCREASED THEREBY CAUSING THE PRESSURE FLUID IN SAID SPACE TO ESCAPE AT AN INCREASED RATE AND PERMIT THE MOVEMENT OF THE PILOT VALVE ELEMENT WITH A SNAP ACTION FROM ITS OPENED TO ITS CLOSED POSITION WHEN THE CHAMBER PRESSURE REDUCES TO SAID SECOND PRE-SELECTED PRESSURE, VARIABLE MEANS CONTROLLING THE DEGREE OF PRESSURE REDUCTION WHICH OCCURES IN THE CHAMBER IN RELATIONSHIP TO THE DROP IN PRESSURE WHICH IS OCCURING IN THE CONTROLLED AREA BY REASON OF SAID PILOT VALVE ASSEMBLY AND SAID MAIN VALVE MEMBER BEING OPEN, THE RELATIONSHIP OF SAID REDUCTION IN THE CHAMBER TO THE PRESSURE REDUCTION IN THE CONTROLLED AREA DETERMINING THE PRESSURE IN THE CONTROLLED AREA AT WHICH THE PILOT VALVE WILL CLOSE.

Claim 4

A SAFETY RELIEF VALVE DEVICE FOR CONTROLLING THE PRESSURE WITHIN A CONTROLLED AREA INCLUDING, A MAIN VALVE MEMBER HAVING ONE SIDE COMMUNICATING WITH SAID CONTROLLED AREA FOR RELIEVING THE PRESSURE THEREIN WHEN SAID MEMBER IS IN AN OPEN POSITION, A HOUSING HAVING A CHAMBER IN COMMUNICATION WITH THE SECOND SIDE OF THE VALVE MEMBER, MEANS FOR CONDUCTING THE PRESSURE WITHIN THE CONTROLLED AREA TO THE CHAMBER, WHEREBY SAID SECOND SIDE IS EXPOSED TO SAID PRESSURE IN ALL POSITIONS OF SAID MAIN VALVE MEMBER, EQUALIZATION OF PRESSURES A CROSS VALVE MEMBER MAINTAINING SAID MEMBER IN THE CLOSED POSITION AND UNEQUALIZATION OF PRESSURES ACROSS SAID MEMBER MAINTAINING SAID MEMBER IN THE OPEN POSITION, A PILOT VALVE ASSEMBLY INCLUDING A PILOT VALVE ELEMENT MOVABLE WITH RESPECT TO A PILOT VALVE SEAT AND EXPOSED TO THE PRESSURE IN SAID CHAMBER, SAID PILOT VALVE ELEMENT VENTING THER PRESSURE FROM THE CHAMBER WHEN SAID PILOT VALVE ELEMENT IS IN AN OPEN POSITION TO UNEQUALIZE THE PRESSURES ACROSS SAID MAIN VALVE MEMBER AND THEREBY OPEN THE SAME TO RELIEVE THE PRESSURE FROM SAID CONTROLLED AREA, SAID PILOT VALVE ELEMENT BEING RESPONSIVE TO THE PRESSURE IN SAID CHAMBER AND BEING OPENED WHEN SAID PRESSURE REACHES A PRESELECTED PRESSURE AND BEING CLOSED WHEN SAID PRESSURE REDUCES TO A SECOND PRESELECTED PRESSURE, COACTING SURFACES FORMING PART OF SAID PILOT VALVE ASSEMBLY DEFINING A DISCHARGE ORIFICE THROUGH SAID PILOT VALVE ASSEMBLY DOWNSTREAM OF THE PILOT VALVE SEAT AND FORMING A SPACE BETWEEN SAID SEAT AND THE DISCHARGE ORIFICE, ONE OF SAID COACTING SURFACES BEING MOVABLE RELATIVE TO THE OTHER WITH THE PILOT VALVE ELEMENT, SAID COACTING SURFACES BEING TAPERED RELATIVE TO EACH OTHER SO THAT AS THE PILOT VALVE ELEMENT MOVES FROM FULLY OPENED POSITION TO CLOSED POSITION THE EFFECTIVE AREA OF THE ORIFICE IS INCREASED THEREBY CAUSING THE PRESSURE FLUID IN SAID SPACE TO ESCAPE AT AN INCREASED RATE AND PERMIT THE MOVEMENT OF THE PILOT VALVE ELEMENT WITH A SNAP ACTION FROM ITS OPENED TO ITS CLOSED POSITION WHEN THE CHAMBER PRESSURE REDUCES TO SAID SECOND PRE-SELECTED PRESSURE, VARIABLE MEANS CONTROLLING THE DEGREE OF PRESSURE REDUCTION WHICH OCCURES IN THE CHAMBER IN RELATIONSHIP TO THE DROP IN PRESSURE WHICH IS OCCURING IN THE CONTROLLED AREA BY REASON OF SAID PILOT VALVE ASSEMBLY AND SAID MAIN VALVE MEMBER BEING OPEN, THE RELATIONSHIP OF SAID REDUCTION IN THE CHAMBER TO THE PRESSURE REDUCTION IN THE CONTROLLED AREA DETERMINING THE PRESSURE IN THE CONTROLLED AREA AT WHICH THE PILOT VALVE WILL CLOSE.