US 4,718,444 AGranted

Valve seat retraction method and apparatus

AssigneeKF Industries, Inc.

InventorLeon W. Boelte

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Abstract

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.

Claims21

Dependent claims

In a valve assembly having:

a housing with axially spaced inlet and outlet ports, a housing interior region disposed between said inlet and outlet ports, and an access opening disposed proximate said interior region;
a removable cover for sealingly closing said access opening;
a ball valve member disposed in said interior region for controlling flow between said inlet and outlet ports and selectively removable from said interior region through said access opening;
and at least one retractable annular valve seat having a forward end urged axially by a resilient bias force into slidable sealing engagement with said valve member;
means for selectively retracting said valve seat away from said valve member comprising:
a substantially convex camming surface defined as a radially outward-facing surface of said valve seat, said camming surface subtending a cam angle with a reference plane oriented perpendicular to flow through said valve assembly, said cam angle increasing as a function of axial displacement from said forward end of said valve seat;
at least one threaded retraction port defined through said housing and extending radially inward from outside said housing to a location in said interior region juxtaposed with said camming surface of said valve seat at an axial position rearward of said forward end when said valve member and said valve seat are in sealing engagement;
selectively removable sealing means for sealing said one retraction port during operation of said valve assembly;
and
first retraction tool means adapted for radial insertion into said interior region through said one retraction port when said sealing means is removed from said retraction port, said retraction tool means having a distal end and a threaded shaft portion for threadedly engaging said threaded retraction port, said distal end being oriented to contact said camming surface and forcefully axially displace said valve seat from said valve member as said distal tool end is increasingly extended radially into said housing interior region, whereby the cam angle at the point of contact between said camming surface and said distal tool end changes and becomes smaller as the radial insertion of said retraction tool means increases and said distal end slides along the camming surface.

7 more elements

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.

In a valve assembly having:

a housing with spaced inlet and outlet ports and a housing interior region disposed between said inlet and outlet ports;
a ball valve member disposed in said housing interior region for controlling flow between said inlet and outlet ports;
and at least one retractable annular valve seat having a camming surface at its forward end urged axially by a resilient bias force into slidable sealing engagement with said valve member;
means for selectively retracting said valve seat away from said valve member comprising:
at least one threaded retraction port defined through said housing and extending inwardly from outside said housing to a location juxtaposed with said valve seat at an axial position rearward of said forward end when said valve member and said valve seat are in sealing engagement;
selectively removable sealing means for sealing said one retraction port during operation of said valve assembly;
a threaded retraction tool adapted to be rotated in a first sense in threaded engagement with said retraction port so as to be inserted through said retraction port into contact with said valve seat when said sealing means is removed from said retraction port;
and
camming means for converting said rotation in said first sense of said threaded tool into lineal displacement of said valve seat away from said ball valve member and in opposition to said resilient bias force, said camming means includes a point of contact between the valve seat and the retraction tool for applying a variable and rotatably settable retraction 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.

6 more elements

Dependencies are inferred from the claim text.