Valve stem assembly for rotary valve and method

A valve body defines a valve stem opening. A valve stem comprises an enlarged portion greater than the valve stem opening to thereby secure the valve stem within the valve body by limiting radially outward movement of the valve stem with respect to the valve body. A rotary member comprise upper and lower bosses. Upper and lower split trunnions, with split components that can be inserted from opposite sides of the valve body, are used to rotationally support the upper and lower bosses to permit rotation of the rotary member while preventing axial movement of the axial flow path of the valve.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to rotary valves and, more particularly, to an improved valve stem assembly.

2. Description of the Background

Larger diameter rotary valves, such as ball valves and plug valves, may typically utilize trunnions to secure the rotary element within the valve body. In other words, the rotary element is trunnion mounted. As an alternative to trunnion mounting of the rotary element, smaller valves may allow the rotary element to float within the valve body. In these smaller valves, an enlarged end may then be provided on the valve stem to retain the valve stem within the valve body. The enlarged end of the valve stem secures the valve stem in the valve body making the stem virtually blow out proof. However, for trunnion mounted rotary elements, the enlarged end cannot be used because the valve stem and rotary element cannot be inserted into the body due to the presence of the trunnions.

Therefore, in valves used in the last several decades, the trunnion mounted rotary elements utilize an external plate to secure the valve stem to the valve body. The plate is bolted onto the valve body. The valve stem may then have an enlarged end, which is larger than the opening in the plate bolted onto the valve but is not larger than the opening in the rotary valve through which the stem is used to engage and rotate the rotary element.

However in this type of valve, which has been used for decades, forces produced by the actuator by repeatedly opening and closing the valves may cause the bolts holding the plate to the body to fatigue whereupon there is a potential that the valve stem may be released from the valve when the valve is under pressure.

The prior art discussed above does not show a design that does not rely on body bolting or fasteners of any kind to retain the valve stem within the pressure area of a valve with a trunnion mounted rotary element. Those of skill in the art will appreciate the present invention that addresses the above needs and other significant needs, the solution to which are discussed hereinafter.

SUMMARY OF THE INVENTION

An object of the present invention is to provide an improved rotary valve.

Another object of the present invention is to provide a blowout proof valve stem, while using a trunnion mounted rotary element.

Yet another object of the present invention is to provide a valve body retained valve stem wherein the rotary element is trunnion mounted.

These and other objects, features, and advantages of the present invention will become apparent from the drawings, the descriptions given herein, and the appended claims. However, it will be understood that the above-listed objectives and/or advantages of the invention are intended only as an aid in quickly understanding aspects of the invention, are not intended to limit the invention in any way, and therefore do not form a comprehensive or restrictive list of objectives, and/or features, and/or advantages.

Accordingly, the present invention provides a rotary valve, which comprises a valve body, which defines a valve stem opening. The valve stem comprises an enlarged portion with a maximum diameter greater than the inner diameter of the valve stem opening, which thereby secures the valve stem within the valve body by limiting radially outward movement of the valve stem with respect to the valve body. A first set of split support elements comprises at least two separable sections which are mountable within the valve body from opposite sides of the valve body. When mounted within the valve body, the first set of split support elements may define a first opening therethrough.

In one embodiment, a rotary member has a first extension positioned within the first opening defined within the first set of split support elements whereby the first extension is rotatable within the first opening. The first extension is interconnectable with the valve stem within the valve body, whereby the rotary member rotates in response to rotation of the valve stem.

In one embodiment, the rotary valve may further comprise a second set of split support elements with at least two separable sections which are mountable within the valve body from opposite sides of the valve body.

When mounted within the valve body the second set of split support elements may in another possible embodiment define a second opening therethrough. In this embodiment, a second extension on the rotary member is positioned on an opposite side of the rotary member from the first extension. The second extension is positioned within the second opening defined within the first set of split support elements whereby the first extension is rotatable within the second opening.

The rotary valve may further comprise a first bearing mounted in the first opening around the first extension and a second bearing mounted in the second opening around the second extension.

The rotary valve further comprises a first end connector mountable to the valve body and a second end connector mountable to the valve body opposite to the first section. The first end connector and the second end connector secure the split support elements together within the valve body.

In one embodiment, the rotary member is ball shaped. In one embodiment, the first extension is cylindrical.

The rotary valve may further comprise a stem thrust washer mounted on the enlarged end of the valve stem which engages an inner surface of the valve body.

In another embodiment, a method for making a rotary valve comprises steps such as inserting a valve stem through an opening in a valve body and utilizing an enlarged portion of the valve stem which does not pass through the opening to retain the valve stem within the valve body.

Other steps may comprise inserting a rotary element into the valve body, whereby an upper extension of the rotary element engages the valve stem, and supporting a first extension on the rotary valve for rotational movement by inserting a first set of split support elements from opposite ends of the valve body.

The method may also comprise supporting a second extension on the rotary valve for rotational movement by inserting a second set of split support elements from opposite ends of the valve body. In this case, the method may comprise utilizing a first end connector and a second end connector for securing the first set of split support elements and the second set of split support elements within the valve body. The method may comprise positioning a first bearing around the first extension and positioning a second bearing around the second extension.

In one embodiment, the method may comprise positioning a thrust washer on the enlarged end of the valve stem to engage an inner surface of the valve body.

In one embodiment, the method may comprise providing that the first set of split support elements define a first opening which receives the first extension.

In another possible embodiment, the rotary valve, may comprise a valve body, which defines a valve stem opening, a valve stem with an enlarged portion greater than the valve stem opening to thereby secure the valve stem. A rotary member may comprise a first portion at one side thereof. A first set of split support elements may comprise at least two separable sections which are mountable within the valve body from opposite sides of the valve body. The first set of split support elements constrain the first portion of the rotary member for rotational movement. The rotary member is interconnectable with the valve stem within the valve body, whereby the rotary member rotates in response to rotation of the valve stem. The rotary member comprises a second portion at a second side of the rotary member opposite to the first side.

In one embodiment, a second set of split support elements may comprise at least two separable sections which are mountable within the valve body from opposite sides of the valve body. Once mounted within the valve body, the second set of split support elements constrain the first portion of the rotary member for rotational movement and prevent axial movement along the axis of the flow path through the valve.

In one embodiment, the first portion of the rotary member comprises a first cylindrical extension and the second portion of the rotary member comprises a second cylindrical extension.

In another embodiment, a rotary valve may comprise a valve body, which defines a valve stem opening, and a valve stem with an enlarged portion relative to the valve stem opening to thereby secure the valve stem within the valve body.

The rotary member may comprise upper and lower bosses. Upper and lower split trunnions may be utilized to rotationally support the upper and lower bosses for rotation of the rotary member.

The rotary valve may further comprise upper and lower trunnion bearings around the upper and lower bosses.

In another embodiment, a method for making a rotary valve may comprise inserting a valve stem through an opening in a valve body whereby the opening retains a relatively enlarged portion of the valve stem within the valve body.

Other steps may comprise inserting a rotary element into the valve body whereby an upper boss engages the valve stem, which may be enlarged portion of the valve stem.

Additionally, the method may comprise supporting upper and lower bosses on the rotary valve by inserting upper and lower split trunnion elements from opposite ends of the valve body.

While the present invention will be described in connection with presently preferred embodiments, it will be understood that it is not intended to limit the invention to those embodiments. On the contrary, it is intended to cover all alternatives, modifications, and equivalents included within the spirit of the invention and as defined in the appended claims.

DESCRIPTION OF PRESENTLY PREFERRED EMBODIMENTS

Referring now to the drawings, and more particularly toFIG. 1andFIG. 2, the present invention teaches rotary valve10, in this case a ball valve, which provides a body retained valve stem16within valve body12.

Valve body12defines valve stem opening14therein. In one embodiment, valve stem opening14is a straight-sided cylindrical opening. However, valve stem opening14could also have other configurations. Valve stem16may comprise cylindrical elongate body18with enlarged portion20at one end thereof, which may also be cylindrically shaped. Enlarged portion20is greater in diameter than valve stem opening14and is therefore retained within valve body12with the full strength of wall24of valve body12, and without the need for reliance on bolts or fasteners.

Enlarged portion20may be formed in different ways and, in this embodiment, can comprise any enlarged component or portion of valve stem16which directly or indirectly engages an interior surface of valve body wall24or an interior portion of valve stem opening14to limit radially outward movement of valve stem16and retain valve stem16within valve body12. As a different example, enlarged end20might comprise a thrust bearing or the like which is enlarged with respect to valve stem opening14.

In another example, valve stem16might comprise a conical or tapered portion which engages a conical or tapered portion of valve stem opening14. Thus, valve stem opening14and valve stem16are designed with any suitable proportions such that valve stem16has a portion which has a larger diameter than at least a portion of valve stem opening14so that valve stem16is retained within valve body12.

During assembly of this embodiment, cylindrical elongate end18of valve stem16is inserted into the interior side of valve stem opening14in valve body12. Enlarged end20is then positioned within body interior22of valve body12whereby the interior surface of valve body12prevents further radially outwardly movement of valve stem16. In this way, the thickness of wall24of valve body12securely retains valve stem16within valve body12, making a blowout proof, body-retained valve stem16. Prior to insertion through valve stem opening14, seals, bearings, and the like may be utilized on valve stem16. While there are many possible arrangement of such elements, in this embodiment, stem thrust washer68, upper stem seal70, and O-ring stem seals72are utilized. Stem thrust washer68then engages the interior surface of wall24of valve body12.

In this embodiment, to enable assembly of a trunnion mounted rotary valve10with body retained valve stem16, split upper and lower trunnions26and28are utilized. The split trunnions comprise separate components26a,26b, and28a,28bthat can be inserted from opposite sides of valve body12.

Depending on the design of the components, lower trunnion28may not need to be split, if desired, due to the absence of the need for a valve stem on the lower side. However, at least upper trunnion26is preferably split so that upper trunnion26can be inserted into valve body12after the rotary element30is inserted into valve body12, and after valve stem16is inserted into the valve body.

As used herein, a trunnion is a support element, which is used to support the upper and lower portions of rotary element30in valve body12for constraining movement of rotary element30to rotational movement without axial movement along the axis of flow path42through rotary valve12. In other words, rotary element30does not “float” along the axis of the flow path as in other types of rotary valves discussed hereinbefore. Thus, the term “support element” or “split support element” may also be utilized to refer to upper and/or lower trunnions26and28. The trunnions engage upper and lower portions of rotary element30, which may be of various shapes and which may or may not comprise extensions or protuberances of rotary element30.

In this embodiment, upper and lower split trunnions26and28are provided to secure or support upper and lower bosses32and34. Upper and lower bosses32and34can be but are not required to be protuberant parts or extensions on the upper and lower sides of rotary element30. In this embodiment, upper and lower bosses32and34comprise cylindrically shaped extensions with a substantially constant diameter over their length.

However, the diameter of upper and lower bosses32and34is not required to be constant, nor is the protuberance or extension required to be straight-sided. For instance, the extension could be rounded where upper boss32now appears to comprise a straight sided cylinder. As another example, the upper and lower bosses may comprise an upper portion of the surface of rotary element30without an extension.

Essentially, upper and lower bosses32and34are mounting support regions on rotary element30which are supported by the upper and lower trunnions so as to be constrained to rotational movement without axial movement along axial flow path42. This contrasts with the floating rotational element of other rotary valves. Upper and lower bosses32and34need not be extensions but may comprise any possible type of pivot region for rotary element30to be supported for or constrained to rotational movement of rotary element30while preventing axial movement along axial flow path42.

In this embodiment, upper and lower trunnions26and28define upper and lower mating cylindrical openings36and38that support upper and lower bosses32and34for rotary movement of rotary element30within valve body12to open and close rotary valve10. The openings or engagement surfaces formed on upper and lower trunnions26and28mate to upper and lower bosses32and34comprise openings and/or bearing surfaces of any shape that conforms to the bosses. While openings36and38comprise straight-sided constant diameter cylindrical openings in this example, as another example, openings36and38may comprise tapered and/or curved diameter openings.

Flow opening40through rotary element30can be rotated parallel or perpendicular to flow path42to open and close rotary valve10. Flow path42may be cylindrical and passes axially through valve10when flow opening40is open.

Upper and lower trunnion components26a,26band28a,28bare compressed together within body interior22and held in place by end connectors44and46to thereby secure upper and lower bosses32and34so movement of rotary element30is constrained to rotational movement without axial movement along flow path42. In other words, rotary element30is not a so-called floating rotary element.

After valve stem16is inserted into valve body12, rotary element30can then be inserted into valve body12for locking engagement with valve stem16. In this embodiment, valve stem16comprises an interlocking member that is inserted into mating groove48in upper boss32to rotationally affix valve stem16to upper boss32whereby rotation of valve stem16results in corresponding rotation of rotary element30. However, various types of interlocking members may be utilized for rotationally affixing or locking valve stem16to upper boss32and the shown interlocking member and mating groove48is only one example thereof.

During assembly of rotary valve10, as indicated inFIG. 1andFIG. 2, end18of valve stem16is inserted through valve stem opening14from interior22of valve body12. Thus, enlarged portion or end20or a thrust bearing or the like engages with an interior surface valve body wall24to prevent valve stem16from being radially outwardly expelled from rotary valve10even when rotary valve10is under high pressure. Rotary element30can then be inserted into valve body12whereby valve stem16interlocks with slot48in upper boss32of rotary element30.

Afterwards, upper and lower split trunnions26and28can be inserted on opposite sides of valve body12to provide that rotary element30is trunnion mounted. It will be appreciated that the trunnion/boss mounting can be of many different configurations. In this case, upper and lower split trunnions26and28are generally rectangular when assembled together and comprise curved outer surfaces49and50. When assembled, openings36and38are slightly larger in inner diameter than the outer diameter of cylindrical bosses32and34.

Prior to insertion of rotary element30into valve body12, upper and lower thrust washers52and54may be positioned on upper and lower bosses32and34. Upper and lower rotary trunnion bearings56and58may also be positioned on upper and lower bosses32and34. Rotary element30may then be tilted during insertion so that groove48can first engage with valve stem16without damaging upper rotary bearing56.

In this embodiment of rotary valve10, rotary element30is ball shaped. However, the present invention might be utilized with any type of rotary valve, such as ball valves, plug valves, and the like.

In this embodiment, a set of primary seals72and secondary seals74are utilized to seal between cylindrical flow path42through rotary valve10and opposite sides of rotary element30. However, other seals can also be utilized to seal rotary element30in accord with the present invention, if desired.

End connectors44and46of valve10secure the trunnions, seals, and other elements within valve body12utilizing fasteners, screws, bolts, studs, nuts and/or the like as indicated at60.

Valve stem16also extends through opening62in adaptor plate64, which is utilized and mounted by fasteners, screws, bolts, studs, nuts and/or the like as indicated at66. However, adaptor plate64is not necessary for securing valve stem16to valve body12. Instead, valve stem16is inserted into valve body12so that enlargement20, which in this embodiment is on the bottom end of valve stem16, retains valve stem16within valve body12without the need for fasteners. In this embodiment, adaptor plate64is used for connecting an actuator (not shown) to valve body12.

During assembly, O-ring seals73, upper stem seal70and thrust washer bearing68may be positioned on valve stem16. Thrust washers52,54and rotary trunnion bearings56,58are placed on upper and lower bosses32,34of rotary element30. If desired, rotary element30can then, be inserted into valve body12at an angle so that the connector on valve stem16engages groove48or other interconnection element on upper boss32of rotary element30. With these components in place within valve body12, then upper and lower split trunnions26,28can be inserted around upper and lower bosses32,34from opposite sides of valve body12. Primary72and secondary seal74assemblies are installed on opposite sides of rotary element30and end connectors44and46are attached to opposite sides of valve body12. Then actuator adaptor plate64can be bolted into place using ferryhead screws66, or the like.

In general, it will be understood that such terms as “up,” “down,” “vertical,” and the like, are made with reference to the drawings and/or the earth and that the devices may not be arranged in such positions at all times depending on variations in operation, transportation, mounting, and the like. For example, terms such as “upper” and “lower” might also be replaced by terms such as “first” and “second” herein. As well, the drawings are intended to describe the concepts of the invention so that the presently preferred embodiments of the invention will be plainly disclosed to one of skill in the art but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation of the invention. One of skill in the art upon reviewing this specification will understand that the relative size and shape of the components may be greatly different from that shown and the invention can still operate in accord with the novel principals taught herein.

Accordingly, the foregoing disclosure and description of the invention is illustrative and explanatory thereof, and it will be appreciated by those skilled in the art, that various changes in the ordering of steps, ranges, interferences, spacings, hardware, and/or attributes and parameters, as well as in the details of the illustrations or combinations of features of the methods and system discussed herein, may be made without departing from the spirit of the invention.