Valve packing shield for use in hydrocarbon operations

A valve assembly includes a valve body defining a flow passage and a body cavity perpendicular to the flow passage. A bonnet is secured to the valve body. A valve member is moveable between an open position and a closed position, the valve member blocking the flow passage in the closed position, and allowing flow through the flow passage in the open position. A valve stem is coupled to the valve member. A debris barrier circumscribes the valve stem. The debris barrier comprises a first disk shaped member with a central opening through which the valve stem is inserted, and notches that extend radially from the central opening to define petals with ends that abut the valve stem.

BACKGROUND

1. Field of Invention

This invention relates in general to manual and actuated valves, and in particular to a barrier for prolonging the life of the stem, packing of the bonnet assembly of a valve associated with hydrocarbon operations.

2. Description of Prior Art

Valves can sometimes have a linearly translating member, such as a valve stem, to move the valve between the open and closed positions. A valve actuator can move the valve stem linearly to move the valve between the open and closed positions. A valve bonnet can be located between and join the valve and the valve actuator. A stem packing can be located around the valve stem, between an outer diameter of me valve stem and an inner diameter of a bore of the bonnet, to prevent fluids from escaping around the valve stem.

During operation, environmental factors can cause damage which results in valve degradation and, eventually, failure of the stem packing. As an example, for valves associated with hydrocarbon operations, debris and other impurities from the well fluids can damage valve components. One practice is to apply grease to lubricate the valve in an attempt to reduce the amount of damage and wear. However, the grease erodes away, leaving the valve assembly exposed. As a result, debris collects on the stem and travels up past the back-seating area to the stem packing causing damage.

SUMMARY OF THE DISCLOSURE

The methods aid systems of the current disclosure prolong the life of stem packing and reduce damage to critical sealing components of a valve assembly. The cost of the debris barrier described in embodiments herein represents a minimal incremental, expense over the total cost of a valve assembly, while allowing the valve assembly to have longer operational periods between servicing and maintenance of the valve assembly. The methods and systems of embodiments herein provide a debris barrier that is not a sealing device, but can keep debris and other impurities from steam or other fluid flows from reaching the stem packing.

In an embodiment of this disclosure, a valve assembly includes a valve body defining a flow passage and a body cavity perpendicular to the flow passage. A bonnet is secured to the valve body. A valve member is moveable between an open position and a closed position, the valve member blocking the flow passage in the closed position, and allowing flow through the flow passage in the open position. A valve stem, is coupled to the valve member. A debris barrier circumscribes the valve stem. The debris barrier comprises a first disk shaped member with a central opening through which the valve stem is inserted, and notches that extend radially from the central opening to define petals with ends that abut the valve stem.

In an alternate embodiment of this disclosure, a valve assembly includes a valve body defining a flow passage and a body cavity perpendicular to the flow passage. A bore extends from an exterior of the valve body through a bonnet of the valve assembly and into the body cavity. A valve member is moveable between an open position and a closed position, the valve member blocking the flow passage in the closed position, and allowing flow through the flow passage in the open position. A valve stem is coupled to the valve member, the valve stem extending through the bore, for moving the valve member between the closed position, to the open position. A stem packing circumscribes a portion of the valve stem, and is located in the bore. A planar debris barrier is located in the valve body and circumscribes the valve stem. The debris barrier comprises triangular shaped petals with corners that are in contact with the valve steal.

In yet another embodiment of the current disclosure, a debris barrier for inserting in a valve assembly includes a first disk shaped member. A central opening is located in the first disk shaped member, the central opening defined by petals. The central opening is sized to accept a valve stem of the valve assembly. The petals are urged apart by the valve stem with inner ends of the petals oriented generally axially along the valve stem.

DETAILED DESCRIPTION OF THE DISCLOSURE

The methods and systems of the present disclosure will, now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The methods and systems of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout.

Referring toFIG. 1, valve assembly10can be a surface valve or can be located subsea. Valve assembly10includes valve body12and bonnet14. Valve body12can be, for example associated with a wellhead assembly that is disposed over a well (not shown). The wellhead assembly can include a wellhead housing, a production tree over the housing and flow lines connected to the tree or the wellhead assembly. The flow lines and wellhead assembly can include embodiments of valve assembly10described herein. Valve body12can also be used for regulating fluids that communicate with the wellhead assembly, or for regulating well and other fluids that are otherwise traveling along a pipeline. Valve stem16passes axially through valve bonnet14, which is secured to valve body12. In the embodiment ofFIG. 1, moving valve stem16towards valve body12will cause valve body12to open. In alternative embodiments, moving valve stem16towards valve body12will cause valve body12to close.

Valve body12is a gate valve housing a body cavity20. A flow passage22formed through valve body12intersects the body cavity20. Body cavity20is perpendicular to flow passage22. A valve member24is shown within the body cavity20. Valve stem16is coupled to valve member24for moving valve member24between the closed position and the open position. In the example ofFIG. 1, valve member24is a gate that is a generally planar member having a solid portion and an opening26formed through the solid portion. Valve member24is selectively slidable within the body cavity20between art open and closed position, wherein valve member24blocks flow passage22in the closed position, and allows flow through flow passage22in the open position. Annular valve seats (not shown) can be located in the flow passage22each having an end extending into the body cavity20. In the embodiment of the valve body12shown inFIG. 1, the opening26does not register with flow passage22and valve body12is therefore in the closed position. In the illustrated embodiment valve body12is shown as a gate valve, but as one of skill in the art will appreciate, valve body12can be any other type of valve that is actuated by the linear extension or translation of a stem, or that is manually moved between the open and closed position by axial or rotational movement of the stem, or by a combination of axial and rotational movement of the stem.

Bore30extends from an exterior of valve body12through bonnet14and into body cavity20. Valve stem16extends through bore30. Stem packing32circumscribes a portion of valve stem16, and is located in bore30. Stem packing32fills an annulus between an outer diameter of valve stem16and an inner diameter of bore30, to prevent fluids from escaping around valve stem16.

Valve stem16has stem sloped surface34. Stem sloped surface34is a radially outward facing annular shoulder located on an outer diameter of valve stem16and proximate to valve member24. Stem sloped surface34is generally oblique to axis Ax and projects downward with distance away from axis Ax. Stem sloped surface34selectively mates with bore sloped surface36to form a metal to metal seal. Bore sloped surface36is a radially inward facing annular shoulder located on an inner diameter of bore30. Stem sloped surface34mates with bore sloped surface36when valve stem16is moved away from valve body12.

Debris barrier38is shown mounted in valve assembly10. Looking now atFIGS. 1-7, debris barrier38is planar and circumscribes valve stem16. Debris barrier38is located within bore30and in the embodiment ofFIGS. 1 and 6, is located at an intersection of valve body12and bonnet14. Debris barrier38is located, axially nearer to valve member24than stem packing32so that fluids in body cavity20, as well as debris and other impurities in the fluids, would come into contact with debris barrier38before coming into contact with stem packing32. In the example ofFIGS. 1 and 6, debris barrier38is also located axially nearer to valve member24than, bore sloped surface36so that fluids in body cavity20, as well as debris and other impurities in the fluids, would come into contact with debris barrier38before coming into contact with bore sloped surface36. In alternate embodiments, debris harder38can be located in bore30between bore sloped surface36and stem packing32. An outer diameter of debris barrier38is greater than or equal to the inner diameter of the of bore30.

Looking again atFIGS. 1-7, debris barrier38includes at least one disk shaped member40with central opening42which extends axially through the mid portion of disk shaped member40. Debris barrier38does not form a seal around valve stem16or between, valve stem16and bore30. Central opening42is sized to unsealingly accept valve stem16, so that the pressure within valve body12will be the same on the axially upper side of debris barrier38as it is on the axially lower side of debris barrier38.

Central opening42is defined by ends of petals44that surround central opening42. Petals44cast be generally triangular shaped and separated from each other by notches46. In certain embodiments, each notch46is a slit with little to no width so that a side of each petal44is in contact with the sides of each adjacent petal44when debris barrier38is in a relaxed state. In other embodiments, each notch46can have a defined width so that the side of each petal44is spaced apart from the sides of each adjacent petal44when debris barrier38is in a relaxed state, as shown inFIGS. 2-5. Notches46project radially outward in disk shaped member40from central opening42.

In an example, petals44are not necessarily rigid and are separable. Radially inner ends48of each petal44define a petal inner diameter. Valve stem16has an outer diameter that is greater than the petal inner diameter so that there is a friction fit between, disk shaped member40and valve stem16, and petals44can be urged apart such that each notch46becomes a gap between each petal44. Valve stem16extends through the central opening42, urging petals44apart so that inner ends48of petals44point towards valve member24and are oriented generally axially along valve stem16(FIG. 7). Inner ends48are deflected to a direction parallel with axis Ax. In embodiments, the petal inner diameter can be greater than the enter diameter of valve stem16, in which case debris barrier38can be more rigid and still not impede the movement of valve stem16. While debris barrier38can be flexible; it can also be rigid enough to clear debris from valve stem16without collapsing, yet having sufficient flexibility to pass over changes in diameter of valve stem16, such as stem sloped surface34. Debris barrier38can be formed of an elastomeric material or a semi-rigid material. Debris barrier38can be formed of, for example, polyether ether ketone (PEEK), calendered fabric, or para-aramid synthetic fiber weave, such as Kevlar™.

Petals44are sized to engage an outer surface of valve stem16to prevent debris that accumulates on valve stem16from reaching stem packing32. In other embodiments, petals44can be sized to pass over stem sloped surface34to prevent debris that accumulates on valve stem16from interfering with the metal to metal seal between stem sloped surface34and bore sloped surface36. Debris barrier38can remove debris from stem sloped surface34prior to valve stem16back-seating on bore sloped surface36; any debris on die stem sloped surface34may keep the metal to metal seal between stem sloped surface34and bore sloped surface36from occurring.

Debris barrier38can include first and second disk shaped members40or can include a plurality of disk shaped members40. Each of the disk shaped members40circumscribe valve stem16and are located within bore30. Disk shaped members40can be stacked adjacent to, and in contact with, each other, or can be axially spaced along an axial length of bore30. In embodiments having two or more debris barriers38, notches46of each debris barrier38can be offset from notches46of each adjacent debris barrier38; and petals44of each debris barrier38can be offset from petals44of each adjacent debris barrier38. For example, all or a portion of notches46of one debris barrier38can be rotationally aligned with a portion of petal44of an adjacent debris barrier38so that notches46of the adjacent debris barriers38are not rotationally aligned. In embodiments, a sufficient number of debris barriers38are used so that one or more petals44blocks the straight line path through each of the notches46.

In examples having at least two disk shaped members40, disk shaped members40can have a connector feature for mating the disk shaped members40. In the example ofFIGS. 4-5, the connector feature can be, for example, male and female dovetail connectors49a,49b. Male and female dovetail connectors49a,49bcan be spaced, around an outer diameter of disk shaped member40and extend axially. Dovetail connectors49of adjacent disk shaped members40can nest and mate to restrict relative rotational movement between the adjacent disk shaped members40.

Returning toFIGS. 1-7, debris barrier38is fixed axially relative to bonnet14and valve stem16moves axially within central opening42of debris barrier38as valve member24moves between the open position and the closed position. The retaining force between bonnet14and debris barrier38is greater than the friction three between the petal inner diameter and the outer diameter of valve stem16, so that valve stem16moves relative to debris barrier38. In embodiments, a friction fit between the outer diameter of debris barrier38and an inner diameter of bore30is sufficient to hold debris barrier38in position. In other embodiments, a retainer can be used to retain debris barrier38in position.

Debris barrier38can have a plurality of barrier holes50that project axially through debris barrier38and spaced around a circumference of debris barrier38. Bonnet14can have a plurality of bonnet holes52extending axially into bonnet14. A plurality of securing members54pass through one of the barrier holes50and into one of the bonnet holes52, securing debris barrier38to bonnet14. In certain embodiments, retainer ring56secures an annular portion of debris barrier38to bonnet14. Retainer ring56is a ring shaped member with an outer diameter that can be similar to an outer diameter of debris barrier38and an inner diameter such that retainer ring56does not interfere with petals44. A face of retainer ring56can have holes through which securing members54pass. In other embodiments, there is no retainer ring56. Other retention means, such as a dovetail groove in bonnet14, adhesive, snap ring or gland nuts can be used to secure debris barrier38to bonnet14.

In an example of operation, debris barrier38having one or more disk shaped members40can be mounted in valve assembly10. Disk shaped members40are mounted in valve assembly10so that valve stem16extends through the central opening42, urging petals44apart so that inner ends48of petals44point towards valve member24and are oriented generally axially along valve stem16. As valve member24is moved towards a closed position, petals44will slide along valve stem16, preventing debris on valve stem16from remaining on valve stem16as valve stem16continues to move farther within bore30. Valve stem16can rotate relative to petals44as opposed to, or in addition to, moving axially along valve stem16. Debris is therefore prevented from reaching stem, packing32within bore30. Petals44can pass over stem sloped surface34to prevent debris that accumulates on valve stem16from, interfering with, the metal to metal seal between stem sloped surface34and bore sloped surface36that will be formed when valve member24is in the closed position.

The terms “vertical”, “horizontal”, “upward”, “downward”, “above”, and “below” and similar spatial relation terminology are used herein only for convenience because elements of the current disclosure may be installed in various relative positions.

The system and method described herein, therefore, are well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the system and method, has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the system, and method disclosed herein and the scope of the appended claims.