| 主权项 |
1. A method comprising:
locating a flow control assembly in a portion of an axial fluid flow bore disposed through a valve body, the axial fluid flow bore having an inlet end located opposite an outlet end, the flow control assembly comprising a flow control element disposed between, and having an outer surface in sealing contact with an inner annular surface of an inlet valve seat and an inner annular surface of an outlet valve seat, wherein the flow control element is rotatable between an open and a closed position; wherein at least a portion of the inner annular surface of the inlet valve seat, the inner annular surface of the outlet valve seat, or a combination thereof, comprise a sealing face dimensioned and arranged to sealingly engage a portion of the outer surface of the fluid flow control element; wherein at least a portion of the inner annular surface of the inlet valve seat, the inner annular surface of the outlet valve seat, or a combination thereof, comprise a plurality of support surfaces dimensioned and arranged in physical contact with the outer surface of the fluid flow control element adjacent the sealing face; wherein the inlet valve seat, the outlet valve seat, or a combination thereof comprise a plurality of vent grooves laterally disposed into the inner annular surface of the valve seat between the plurality of support surfaces; rotationally engaging an inner end of a valve stem in a corresponding recess of the flow control element, the valve stem extending from an outer end through a packing bore disposed radially around the valve stem in the valve body to an inner end of the valve stem, wherein the inner end of the valve stem comprises a plurality of sides, the recess having a corresponding number of sides, wherein a distance between the sides of the recess are dimensioned relative to a distance between the plurality of sides of the first end of the valve stem to allow for an amount of lateral movement of the flow control element between the fluid flow bore inlet end and the fluid flow bore outlet end; applying a pressurized fluid to the inlet end of the fluid flow bore to laterally move the flow control assembly towards the outlet end of the fluid flow bore in an amount sufficient to produce sealing contact between an outer annular surface of the outlet valve seat with a portion of the valve body; applying a pressurized fluid to the outlet end of the fluid flow bore to laterally move the flow control assembly towards the inlet end of the fluid flow bore in an amount sufficient to produce sealing contact between an outer annular surface of the inlet valve seat and a portion of the valve body; rotating the valve stem such that the flow control element is in the closed position prior to or after the application of the pressurized fluid to the inlet or outlet end of the flow bore, the pressurized fluid having a pressure of greater than 275.8 MPa (40,000 psi) and a temperature of greater than or equal to about 200° C.; and maintaining the pressure of greater than 275.8 MPa (40,000 psi) and temperature of greater than or equal to about 200° C. for at least 1 hour, wherein the fluid is maintained by the valve without leaking past the flow control element into the respective inlet or outlet end of the fluid flow bore. |
