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Selective retraction of a spring-biased valve seat from slidable sealing engagement with a ball valve member is effected by a threaded retraction tool inserted through a threaded retraction port normally sealed by a removable sealing screw and gasket. The tapered distal end of the tool contacts a ra

Selective retraction of a spring-biased valve seat from slidable sealing engagement with a ball valve member is effected by a threaded retraction tool inserted through a threaded retraction port normally sealed by a removable sealing screw and gasket. The tapered distal end of the tool contacts a radially outward-facing and convex camming surface of the valve seat that tapers toward the forward/sealing end of the seat. Rotation of the tool in a direction to increase insertion causes the distal end of the tool to slide along the camming surface while forcing the valve seat away from the valve ball in opposition to the resilient bias sealing force. The taper in the camming surface may be provided as a smooth generally parabolodial configuration or as discrete surface segments subtending different respective cam angles with a reference plane oriented perpendicular to the direction of the spring bias force.

대표청구항 ▼

The method of retracting a valve seat, located in a valve housing, away from slidable sealing engagement with a ball valve member in opposition to a resilient bias force urging the forward end of the valve seat against the ball valve member, said method comprising the step of: threadedly inserting a

The method of retracting a valve seat, located in a valve housing, away from slidable sealing engagement with a ball valve member in opposition to a resilient bias force urging the forward end of the valve seat against the ball valve member, said method comprising the step of: threadedly inserting a retraction tool into said valve housing via a retraction port in a direction perpendicular to the direction of said bias force to slide the distal end of said retraction tool along a convex camming surface of said valve seat which tapers toward said forward end of the valve seat, thereby forcefully displacing said valve seat from said ball valve member, by applying a variable and rotatably settable force to said valve seat at said camming surface in opposition to said resilient bias force, the retraction force increasing as the depth of insertion of said retraction tool increases with the rotatable setting.