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Method and apparatus for configuring a pressure relief valve to have a desired internal orifice size. A population of nominally identical inserts are provided having different internal orifice diameters. A resilient seal ring is placed upon a selected insert and both are inserted into a cup-shaped s

Method and apparatus for configuring a pressure relief valve to have a desired internal orifice size. A population of nominally identical inserts are provided having different internal orifice diameters. A resilient seal ring is placed upon a selected insert and both are inserted into a cup-shaped seat body to form a valve seat assembly. The valve seat assembly is secured within a housing of the pressure relief valve in facing relationship to a moveable piston assembly which is biased against the seal in a normally closed position. When a new internal orifice size is desired, the insert is removed and replaced with a new insert having the new desired orifice size. No changes are necessary in the remaining components. The resilient seal preferably comprises a stiffener ring of rigid material surrounded by an annular ring of resilient material.

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1. A valve seat assembly for use in a pressure relief valve having a moveable piston assembly which is biased against the valve seat assembly in a normally closed position and which moves away from the valve seat assembly when a pressure of an inlet pressurized fluid reaches a predetermined threshol

1. A valve seat assembly for use in a pressure relief valve having a moveable piston assembly which is biased against the valve seat assembly in a normally closed position and which moves away from the valve seat assembly when a pressure of an inlet pressurized fluid reaches a predetermined threshold, the valve seat assembly comprising:a substantially cup-shaped seat body comprising an annular wall and an inwardly directed, annular seat flange, the annular wall having opposing first and second ends, an inner surface and an outer surface, wherein the annular seat flange extends from the first end of the annular wall to abut the piston assembly when the pressure relief valve is in the closed position; anda first insert comprising an annular wall with opposing first and second ends, an outer surface and an inner orifice of a first diameter, wherein the first insert slidingly engages the seat body so that the outer surface of the first insert abuts the inner surface of the seat body, the inner orifice metering a flow rate of fluid through the valve seat assembly;wherein the seat body is further configured to accommodate a replacement, second insert comprising an annular wall with opposing first and second ends, an outer surface and an inner orifice of a second diameter less than the first diameter, the inner orifice of the second insert metering a second flow rate of fluid through the valve seat assembly less than that provided by the inner orifice of the first insert. 2. The valve seat assembly of claim 1, further comprising a resilient seal ring configured to be supported by the first end of the first insert and disposed between the insert and the annular seat flange of the seat body, the seal ring having an annular contact surface configured to abuttingly receive the piston assembly and establish a fluidic seal when the pressure relief valve is in the closed position, wherein the resilient seal ring is further configured to be supported by the first end of the second insert. 3. The valve seat assembly of claim 1, wherein the valve seat assembly is reconfigured by steps comprising:removing the first insert from the seat body; andinserting the second insert into the seat body so that the outer surface of the second insert abuts the inner surface of the seat body. 4. The valve seat assembly of claim 1, wherein the inner orifice surface of the first insert extends from the first end of the annular wall of the first insert to a medial portion of said annular wall, and wherein said annular wall further comprises an inclined, interior first conical surface which tapers from the second end of said annular wall to the inner orifice surface of the first insert, the first conical surface defining an inlet aperture at the second end having a diameter larger than the first diameter of the internal orifice defined by the inner orifice surface. 5. The valve seat assembly of claim 4, wherein the inner orifice surface of the second insert extends from the first end of the annular wall of the second insert to a medial portion of said annular wall, and wherein said annular wall further comprises an inclined, interior second conical surface which tapers from the second end of said annular wall to the inner orifice surface of the second insert, and wherein the second conical surface defines a second inlet aperture at the second end of the second insert nominally equal to the diameter of the inlet aperture at the second end of the first insert. 6. The valve seat assembly of claim 5, wherein the first conical surface extends at an inclined angle substantially equal to an inclined angle at which the second conical surface extends. 7. The valve seat assembly of claim 1, wherein the outer surface of the annular wall of the seat body further comprises threads which engage a threaded aperture in a housing of the pressure relief valve to secure the valve seat assembly to the housing. 8. The valve seat assembly of claim 2, wherein the resilient seal ring c omprises:an annular ring of rigid material; andan annular ring of resilient material surrounding and attached to the annular ring of rigid material. 9. The valve seat assembly of claim 8, wherein the rigid material comprises steel. 10. The valve seat assembly of claim 8, wherein the resilient material comprises rubber. 11. A method for configuring a pressure relief valve, comprising:providing a population of nominally identical inserts each comprising an annular wall with opposing first and second ends, an outer surface and an inner orifice surface, wherein the inner orifice surface of a first insert from the population defines an orifice having a first diameter and wherein the inner orifice surface of a second insert from the population defines an orifice having a second diameter;placing a resilient seal ring onto the first end of the first insert;sliding the first insert and the resilient seal ring into a substantially cup-shaped seat body to form a valve seat assembly, the seat body comprising an annular wall and an inwardly directed, annular seat flange, the annular wall of the seat body having opposing first and second ends, an inner surface and an outer surface so that the outer surface of the first insert abuts the inner surface of the seat body; andinstalling the valve seat assembly into a rigid housing of the pressure relief valve in a facing relationship to a moveable piston assembly which establishes a fluidic seal against the resilient seal ring when the pressure relief valve is in a closed position. 12. The method of claim 11, further comprising:removing the valve seat assembly from the housing;removing the first insert and the resilient seal ring from the seat body;placing the resilient seal ring onto the first end of the second insert; andsliding the seal ring and the second insert into the seat body so that the outer surface of the second insert abuts the inner surface of the seat body, thereby forming a second valve seat assembly with an orifice at the second diameter. 13. The method of claim 12, further comprising:installing the second valve seat assembly into the rigid housing of the pressure relief valve in a facing relationship to the moveable piston assembly which establishes a fluidic seal against the resilient seal ring when the pressure relief valve is in the closed position. 14. The method of claim 11, wherein the inner orifice surface of the first insert of the providing step extends from the first end of the annular wall of the first insert to a medial portion of said annular wall, and wherein said annular wall further comprises an inclined, interior first conical surface which tapers from the second end of said annular wall to the inner orifice surface of the first insert, the first conical surface defining an inlet aperture at the second end having a diameter larger than the first diameter of the internal orifice defined by the inner orifice surface. 15. The method of claim 14, wherein the inner orifice surface of the second insert of the providing step extends from the first end of the annular wall of the second insert to a medial portion of said annular wall, and wherein said annular wall further comprises an inclined, interior second conical surface which tapers from the second end of said annular wall to the inner orifice surface of the second insert, and wherein the second conical surface defines a second inlet aperture at the second end of the second insert nominally equal to the diameter of the inlet aperture at the second end of the first insert. 16. The method of claim 15, wherein the providing step further comprises configuring the first conical surface and the second conical surface to extend at a common inclined angle. 17. The method of claim 15, wherein the installing step further comprises rotating the valve seat assembly so that threads in the outer surface of the seat body engage a threaded aperture in the housing to secure the valve seat assembly to the housing. 18. The method of claim 11, wherein the placing step comprises configuring the resilient seal ring to comprise an annular ring of resilient material which surrounds and is attached to an inner, annular ring of rigid material. 19. The method of claim 18, wherein the rigid material of the resilient seal ring of the placing step comprises steel. 20. The method of claim 18, wherein the resilient material of the resilient seal ring of the placing step comprises rubber.