Ball valve assembly

A ball valve assembly includes a ball configured to rotate between an open position and a closed position. The ball valve assembly also includes a cradle having a ball-facing surface. The ball-facing surface faces the ball and is positioned at an end of a fluid passage through the cradle. In addition, the cradle is configured to rotatably support the ball to enable the ball to rotate between the open position and the closed position, and the cradle is configured to block movement of the ball toward the ball-facing surface to establish a separation distance between the ball and the ball-facing surface.

BACKGROUND

This section is intended to introduce the reader to various aspects of art that may be related to various aspects of the presently described embodiments. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present embodiments. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art.

In order to meet consumer and industrial demand for natural resources, companies search for and extract oil, natural gas, and other subterranean resources from the earth. Once a desired subterranean resource is discovered, drilling and production systems are employed to access and extract the resource. These systems may be located onshore or offshore depending on the location of a desired resource. For example, in subsea operations, hydrocarbon fluids such as oil and natural gas are obtained from a subterranean geologic formation, referred to as a reservoir, by drilling a well that penetrates the hydrocarbon-bearing geologic formation. In various subsea applications and other well applications, ball valve assemblies are used to control fluid flow through a well string. Ball valve assemblies include a ball having a fluid pathway extending through the ball. While the ball valve assembly is in an open state (e.g., open position of the ball), the fluid pathway of the ball is aligned with a fluid passage of the ball valve assembly, thereby enabling fluid to flow through the ball valve assembly. In addition, while the ball valve assembly is in a closed state (e.g., closed position of the ball), the fluid pathway of the ball is oriented generally perpendicularly to the fluid passage of the ball valve assembly, thereby blocking fluid flow through the ball valve assembly. In certain ball valve assemblies, the ball is supported by/captured between a seal retainer and a cradle. A seal is coupled to the seal retainer and engaged with the ball, and a bushing is coupled to the cradle and engaged with the ball. While the ball is in the closed position, fluid pressure within the fluid passage (e.g., above-ball fluid pressure) may drive the ball into engagement with the bushing on the cradle. Due to the static friction between the ball and the bushing, the actuator assembly, which is configured to drive the ball to rotate between the open and closed positions, may not provide sufficient force to drive the ball to rotate to the open position. Accordingly, other procedures, such as establishing a significant above-ball fluid pressure within the fluid passage, may be performed to drive the ball to the open position.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

When introducing elements of various embodiments, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Moreover, any use of “top,” “bottom,” “above,” “below,” other directional terms, and variations of these terms is made for convenience, but does not require any particular orientation of the components.

FIG.1is a perspective view of an embodiment of a ball valve assembly10. In certain embodiments, the ball valve assembly10may be disposed along a well string, such as a landing string. For example, the ball valve assembly10may be used as a retainer valve within a subsea landing string. In the illustrated embodiment, the ball valve assembly10includes an inlet12positioned at a first end portion14of the ball valve assembly10, and the ball valve assembly10includes an outlet16positioned at a second end portion18of the ball valve assembly10. The inlet12is configured to receive fluid (e.g., from a well), and the ball valve assembly10is configured to control flow of the fluid through the ball valve assembly10between the inlet12and the outlet16.

The ball valve assembly10includes a ball having a fluid pathway extending through the ball. The ball is configured to rotate between an open position and a closed position. The fluid pathway is configured to align with a fluid passage of the ball valve assembly10while the ball is in the open position to enable fluid flow through the ball valve assembly10. In addition, the fluid pathway is configured to be offset from the fluid passage while the ball is in the closed position to block fluid flow through the ball valve assembly10. Furthermore, the ball valve assembly includes a ball support and actuation assembly configured to support the ball within the ball valve assembly and to drive the ball to rotate between the open position and the closed position. In the illustrated embodiment, the ball support and actuation assembly drives the ball to rotate in response to receiving pressurized hydraulic fluid. Accordingly, the illustrated ball valve assembly10includes first hydraulic input(s) and second hydraulic input(s). Applying pressurized hydraulic fluid to the first hydraulic input(s) causes the ball support and actuation assembly to drive the ball to the closed position, and applying pressurized hydraulic fluid to the second hydraulic input(s) causes the ball support and actuation assembly to drive the ball to the open position. If hydraulic fluid flow to the second hydraulic input(s) is interrupted, a compression spring within the ball valve assembly10may drive the ball to the closed position. Accordingly, the illustrated ball valve assembly is considered a failsafe closed ball valve assembly. However, in other embodiments, the ball valve assembly may be a failsafe open ball valve assembly, a fail-as-is ball valve assembly, or any other suitable type of ball valve assembly.

Furthermore, in certain embodiments, the ball support and actuation assembly includes a cradle having an arm configured to rotatably support the ball. In addition, the ball has a contact surface and the arm of the cradle has a corresponding contact surface. The ball support and actuation assembly also includes a rotation pin engaged with the arm, in which the ball is configured to rotate about the rotation pin. The contact surface of the ball and the corresponding contact surface of the arm of the cradle are spaced apart from one another while a force urging the ball toward the cradle is less than or equal to a threshold force, and the corresponding contact surface of the arm of the cradle is configured to engage the contact surface of the ball to block movement of the ball toward the cradle while the force is greater than the threshold force. Because the contact surfaces are spaced apart from one another while the force is less than or equal to the threshold force, the torque sufficient to drive the ball to rotate between the open and closed position may be significantly reduced (e.g., as compared to a ball that is captured between contact surfaces on uphole and downhole sides, which establishes significant resistance to rotation). In addition, the contact surfaces block movement of the ball toward the cradle while the force urging the ball toward the cradle is greater than the threshold force, thereby blocking contact between the ball and a ball-facing surface of the cradle, which reduces resistance to rotation of the ball.

FIG.2is an exploded perspective view of an embodiment of a ball support and actuation assembly24that may be employed within the ball valve assembly ofFIG.1. In the illustrated embodiment, the ball support and actuation assembly24includes a ball26configured to rotate between an open position and a closed position. The ball26includes a fluid pathway extending through the ball. The fluid pathway is configured to align with a fluid passage of the ball valve assembly while the ball is in the open position to enable fluid flow through the ball valve assembly. In addition, the fluid pathway is configured to be offset from the fluid passage while the ball is in the closed position to block fluid flow through the ball valve assembly. As used herein, “offset” refers to an angle between the fluid pathway and the fluid passage that causes fluid flow through the ball valve assembly to be blocked (e.g., via contact between an outer surface of the ball and respective seal(s)).

The ball support and actuation assembly24also includes a cradle28configured to rotatably support the ball26, thereby enabling the ball26to rotate between the open position and the closed position. In the illustrated embodiment, the cradle28includes arms30, and a rotation pin32is engaged with each arm30. In certain embodiments, each rotation pin32is non-rotatably coupled to the respective arm30, and each rotation pin32is engaged with a respective recess within the ball26. Accordingly, the ball26may rotate about the rotation pins32between the open and closed positions. Furthermore, in the illustrated embodiment, actuation pins34are coupled to the ball26and configured to drive the ball26to rotate about the rotation pins32. Each actuation pin34is configured to engage a respective opening36(e.g., slot) within an operator38of the ball support and actuation assembly24. Movement of the operator38in a first translational direction40drives the actuation pins34to rotate the ball26in a first rotational direction42from the illustrated open position to the closed position. In addition, movement of the operator38in a second translational direction44drives the actuation pins34to rotate the ball26in a second rotational direction46from the closed position to the open position. The openings36are shaped to enable lateral movement of the actuation pins34as the operator38moves in the first and second translational directions. While the actuation pins are fixed to the ball and configured to move within slot-shaped opening in the operator in the illustrated embodiment, in other embodiments, each actuation pin may be coupled to a slider that is disposed within a respective slot in the ball. In such embodiments, translational movement of each actuation pin relative to the operator may be substantially blocked, and the slots in the ball may enable the lateral movement of the actuation pins as the operator moves in the translational directions. However, the friction between the actuation pins and the operator in the illustrated embodiment may be less than the friction between the sliders and the ball in the embodiment disclosed above. Accordingly, the torque sufficient to rotate the ball between the open and closed positions may be less in the illustrated embodiment.

The operator38may be driven to move in the translational directions by any suitable device(s), such as one or more hydraulic pistons, one or more pneumatic pistons, one or more electromechanical actuators, other suitable type(s) of actuator(s), or a combination thereof. Furthermore, in certain embodiments, one or more springs (e.g., compression spring(s), coil spring(s), pneumatic spring(s), hydraulic spring(s), electromagnetic spring(s), leaf spring(s), etc.) may urge the operator to move in the first translational direction40, thereby urging the ball26to rotate toward the closed position. The spring(s) may provide sufficient force to drive the ball to the closed position in response to interruption in operation of the device(s) configured to drive the operator to translate. In such embodiments, the ball valve assembly is considered a failsafe closed ball valve assembly.

Furthermore, in the illustrated embodiment, the ball26has two contact surfaces48(e.g., arcuate contact surfaces), and each arm30of the cradle28has a corresponding contact surface50(e.g., arcuate contact surface). Each contact surface48of the ball26is spaced apart from a corresponding contact surface50of the cradle28while a force urging the ball26toward the cradle28in the second translational direction44is less than or equal to a threshold force. For example, the length of the arms and/or the position of the rotation pins along the arms may establish a target spacing between the respective contact surfaces. Furthermore, each corresponding contact surface50of the cradle28is configured to engage the respective contact surface48of the ball26to block movement of the ball26toward the cradle28in the second translational direction44while the force is greater than the threshold force. Because the contact surfaces are configured to block movement of the ball toward the cradle while a substantial force is applied to the ball (e.g., by fluid pressure, such as above-ball fluid pressure), the rotation pins32may be thinner than rotation pins configured to resist forces above the threshold force, thereby reducing the cost and/or size of the ball valve assembly.

In the illustrated embodiments, a seal retainer52is positioned on an opposite side of the ball26from the cradle28. In certain embodiments, the seal retainer52is urged toward the ball26along the second translational direction44by a spring and/or fluid pressure. A seal may be coupled to the seal retainer52and engaged with the ball26while the ball is in the closed position. Contact between the seal coupled to the seal retainer and the ball blocks fluid flow through the ball valve assembly while the ball is in the closed position.

FIG.3is an exploded perspective view of a portion of the ball support and actuation assembly24ofFIG.2. As previously discussed, the cradle28has two arms30configured to rotatably support the ball26, thereby enabling the ball26to rotate in the first rotational direction42from the illustrated open position to the closed position and to rotate in the second rotational direction46from the closed position to the open position. In the illustrated embodiment, the two arms30are positioned on opposite radial sides of the ball26(e.g., opposite sides of the ball along a radial axis54). Accordingly, the arms30(e.g., circumferential center points of the arms30) are offset from one another by about 180 degrees along a circumferential axis56. While the cradle28includes two arms30in the illustrated embodiment, in other embodiments, the cradle may have fewer arms. For example, the cradle may include a single arm positioned on one side of the ball, or the cradle may not include any arms and a body of the cradle may rotatably support the ball within the ball valve assembly.

In the illustrated embodiment, each arm30includes a respective opening58, and each opening58is configured to receive a respective rotation pin32. In the illustrated embodiment, each rotation pin32is non-rotatably coupled to the respective arm30(e.g., via a press-fit connection, via a threaded connection, via a pinned connection, via a welded connection, via an adhesive connection, via another suitable connection, or a combination thereof). Accordingly, the rotation pins32provide a pivot point for the ball26to rotate between the open position and the closed position. In the illustrated embodiment, the ball26has recesses60configured to receive the respective rotation pins32. While each opening58and each recess60are substantially circular in the illustrated embodiment, in other embodiments, at least one opening and/or at least one recess may have another suitable shape (e.g., elliptical, polygonal, etc.). Furthermore, while each rotation pin is disposed within a respective opening of the cradle in the illustrated embodiment, in other embodiments, at least one pin may be integrally formed with the cradle (e.g., an arm of the cradle).

In addition, the ball support and actuation assembly24includes bearings62disposed about the respective rotation pins32within the respective recesses60. The bearings62are configured to reduce rotational resistance, thereby facilitating rotation of the ball26between the open and closed positions. In the illustrated embodiment, each bearing62is a ball bearing including an outer race non-rotatably coupled to the ball26(e.g., via a press-fit connection, via a threaded connection, via a pinned connection, via a welded connection, via an adhesive connection, via another suitable connection, or a combination thereof). In addition, each bearing62includes an inner race non-rotatably coupled to the respective rotational pin32(e.g., via a press-fit connection, via a threaded connection, via a pinned connection, via a welded connection, via an adhesive connection, via another suitable connection, or a combination thereof). Each bearing62also includes balls disposed between the races to facilitate rotation of the outer race/ball relative to the inner race/rotation pin. While ball bearings are employed within the illustrated embodiment, in other embodiments, other suitable bearing(s) and/or bushing(s) may be disposed within at least one recess to facilitate rotation of the ball relative to the cradle. For example, while a single bearing is disposed within each recess in the illustrated embodiment, in other embodiments, multiple bearings and/or one or more bushings (e.g., alone, in combination with a single bearing, or in combination with multiple bearings) may be disposed within at least one recess. Furthermore, in certain embodiments, no bearings and no bushings may be disposed within at least one recess. In such embodiments, a lubricant may be disposed within the recess(es) to facilitate rotation of the ball relative to the cradle. A lubricant may also be employed within the embodiments having one or more bearings (e.g., within the bearing(s)) and/or one or more bushings (e.g., on an inner surface of each bushing and/or on an outer surface of each bushing).

While the ball support and actuation assembly24includes rotation pins non-rotatably coupled to the cradle28in the illustrated embodiment, in other embodiments, at least one rotation pin may be non-rotatably coupled to the ball, and/or at least one rotation pin may be rotatably coupled to the ball and rotatably coupled to the cradle. For example, in certain embodiments, at least one rotation pin may be non-rotatably coupled to the ball (e.g., the rotation pin may be integrally formed with the ball or coupled to the ball by a suitable connection system). In such embodiments, the rotation pin may be rotatably coupled to the cradle. For example, one or more bearings and/or one or more bushings may be disposed about the rotation pin within the respective opening of the cradle, thereby enabling the rotation pin and the ball to rotate relative to the cradle. Furthermore, in certain embodiments, at least one rotation pin may be rotatably coupled to the ball and rotatably coupled to the cradle. For example, one or more bearings and/or one or more bushings may be disposed about the rotation pin within the respective opening of the cradle, and/or one or more bearings and/or one or more bushings may be disposed about the rotation pin within the respective recess of the ball. In addition, while the ball support and actuation assembly24includes two rotation pins32in the illustrated embodiment, in other embodiments, the ball support and actuation assembly may include a single rotation pin (e.g., in embodiments in which the cradle has a single arm).

As previously discussed, each contact surface48of the ball26is spaced apart from a corresponding contact surface50of the cradle28while a force urging the ball26toward the cradle28in the second translational direction44is less than or equal to a threshold force. The force urging the ball26toward the cradle28may be caused by fluid pressure (e.g., above-ball fluid pressure) acting on the ball26while the ball is in the closed position. While the force urging the ball26toward the cradle28is less than or equal to the threshold force, the rotation pins32substantially maintain the position of the ball26along a longitudinal axis64relative to a ball-facing surface66of the cradle28(e.g., which surrounds a port of the cradle). Accordingly, a separation distance between the ball26and the ball-facing surface66may be maintained while the force urging the ball26toward the cradle28is less than or equal to the threshold force. As a result, the rotational resistance of the ball may be significantly less than the rotational resistance of a ball that is in contact with the ball-facing surface (e.g., bearing surface). Accordingly, a smaller and/or less expensive actuator(s) may be used to drive the ball between the open and closed positions. In addition, the separation distance may enable dirt and/or debris to pass through the ball valve assembly (e.g., as compared to becoming trapped between the ball and the ball-facing surface).

Furthermore, each contact surface50of the cradle28is configured to engage the respective contact surface48of the ball26to block movement of the ball26toward the cradle28along the longitudinal axis64while the force urging the ball toward the cradle is greater than the threshold force. For example, while a force greater than the threshold force is applied to the ball in the second translational direction (e.g., by the above-ball fluid pressure), the rotation pins may bend, a portion of the arms may bend, the bearing(s) may compress, other parts of the ball support and actuation assembly may deform, or a combination thereof, thereby enabling the contact surfaces of the ball to contact the corresponding contact surfaces of the cradle. Because the contact surfaces are configured to block movement of the ball toward the cradle while a substantial force is applied to the ball by fluid pressure (e.g., above-ball fluid pressure), the rotation pins32may be thinner than rotation pins configured to resist forces above the threshold force, thereby reducing the cost and/or size of the ball valve assembly. In certain embodiments, the ball is configured to rotate while the contact surfaces of the ball are engaged with the corresponding contact surfaces of the cradle. In such embodiments, the separation distance between the ball and the ball-facing surface of the cradle may be maintained, thereby reducing resistance to rotation of the ball (e.g., as compared to a ball that is in contact with the ball-facing surface). In certain embodiments, a lubricant and/or bushing(s)/bearing(s) may be disposed on at least one contact surface of the ball and/or at least one corresponding contact surface of the cradle.

The contact surfaces48of the ball26and the corresponding contact surfaces50of the cradle28are positioned remote from the ball-facing surface66. As used herein, “ball-facing surface” refers to a surface of the cradle that faces the ball and is positioned at an end of the fluid passage through the cradle. In certain embodiments, the ball-facing surface is formed on a bushing of the cradle. In the illustrated embodiment, the contact surfaces48of the ball26are formed (e.g., machined, etc.) within a body of the ball. However, in other embodiments, at least one contact surface of the ball may be formed on an extension coupled to the ball. In addition, while each contact surface of the ball is arcuate (e.g., extending about a portion of the respective recess) in the illustrated embodiment, in other embodiments, at least one contact surface of the ball may be annular (e.g., extending about an entire periphery of the recess) or any other suitable shape. Furthermore, in the illustrated embodiment, the corresponding contact surfaces50of the cradle28are formed on the arms30of the cradle28. However, in other embodiments, at least one corresponding contact surface may be formed on any other suitable portion of the cradle (e.g., the body of the cradle, an extension coupled to the cradle, etc.). For example, in certain embodiments, the arms of the cradle may be omitted and the openings may be formed within a body of the cradle. In such embodiments, at least one corresponding contact surface may be formed within the body of the cradle, and/or at least one corresponding contact surface may be formed on an extension coupled to the body of the cradle.

As previously discussed, the contact surfaces of the ball and the corresponding contact surfaces of the cradle are spaced apart from one another while a force urging the ball toward the cradle is less than or equal to the threshold force. In addition, the corresponding contact surfaces of the cradle are configured to engage the respective contact surfaces of the ball to block movement of the ball toward the cradle while the force is greater than the threshold force. The threshold force may be particularly selected for a ball valve assembly. For example, the threshold force may be selected by selecting the spacing between the contact surfaces of the ball and the corresponding contact surfaces of the cradle (e.g., by selecting the length of the arms of the cradle, the position of the corresponding contact surfaces of the cradle relative to the openings for the rotation pins, etc.). In addition, the threshold force may be selected by selecting the stiffness of the rotation pins (e.g., by selecting the diameter/thickness of the rotation pins, by selecting the material that forms in the rotation pins to control bending of the rotation pins, etc.). Accordingly, a target threshold force may be established for each ball valve assembly.

As previously discussed, the actuation pins34are configured to engage respective openings in the operator. Accordingly, translational movement of the operator drives the actuation pins34to translate along the longitudinal axis64, thereby driving the ball to rotate. In the illustrated embodiment, each actuation pin34is disposed within a respective recess68in the ball26. In certain embodiments, at least one actuation pin may be coupled to the ball (e.g., by being press fit into the respective recess, via an adhesive connection, via welding, via a threaded connection, via another suitable connection, or a combination thereof). Furthermore, in certain embodiments, at least one actuation pin may be integrally formed with the body of the ball (e.g., via a machining process, via an additive manufacturing process, via a casting process, or a combination thereof). In certain embodiments, one or more bushings and/or one or more bearing may be disposed about at least one actuation pin, such that the bushing(s)/bearing(s) are disposed between the actuation pin and the operator, thereby facilitating rotation the actuation pin relative to the operator. Furthermore, in certain embodiments, one or more bushings and/or one or more bearings may be disposed about at least one actuation pin, such that the bushing(s)/bearing(s) are disposed between the actuation pin and the ball, thereby facilitating rotation of the actuation pin relative to the ball.

FIG.4is a perspective view of a portion of the ball support and actuation assembly24ofFIG.2, in which the ball26is in the closed position. While the ball26is in the illustrated closed position, the fluid pathway70through the ball26is offset from the fluid passage of the ball valve assembly. In addition, the seal72, which is coupled to the seal retainer52, is in contact with the ball26, thereby blocking fluid flow through the ball valve assembly. Furthermore, in the illustrated embodiment, a portion of the cradle28(e.g., a respective arm30of the cradle28) covers each bearing within the respective recess of the ball. Accordingly, the cradle (e.g., the arms of the cradle) may substantially block dirt and/or debris from entering the recesses/bearings, thereby facilitating rotation of the ball between the open and closed positions. Furthermore, in certain embodiments, wiper seal(s) positioned between one or more respective cradle arm(s)30and the ball may substantially block dirt and/or debris from entering the respective recess(es)/bearing(s).

While the contact surfaces are positioned to block movement of the ball toward the cradle in the illustrated embodiment, in other embodiments, additional contact surfaces may be positioned to block movement of the ball toward the seal retainer. For example, an additional contact surface of the ball may be spaced apart from a corresponding contact surface of the seal retainer (e.g., on an arm of the seal retainer) while a force urging the ball toward the seal retainer is less than or equal to a threshold force (e.g., second threshold force). In addition, the corresponding contact surface of the seal retainer may be configured to engage the additional contact surface of the ball to block movement of the ball toward the seal retainer while the force is greater than the threshold force. As a result, the contact force between the ball and the seal of the seal retainer may be reduced, thereby reducing resistance to rotation of the ball. In certain embodiments, the ball support and actuation assembly may include both types of contact surfaces (e.g., to block movement toward the cradle and to block movement toward the seal retainer), or the ball support and actuation assembly may include a single contact surface type.

FIG.5is an exploded perspective view of another embodiment of a ball support and actuation assembly74that may be employed within the ball valve assembly ofFIG.1. In the illustrated embodiment, the ball support and actuation assembly74includes a ball76configured to rotate between an open position and a closed position. The ball76includes a fluid pathway extending through the ball. The fluid pathway is configured to align with a fluid passage of the ball valve assembly while the ball is in the open position to enable fluid flow through the ball valve assembly. In addition, the fluid pathway is configured to be offset from the fluid passage while the ball is in the closed position to block fluid flow through the ball valve assembly.

The ball support and actuation assembly74also includes a cradle78configured to rotatably support the ball76, thereby enabling the ball76to rotate between the open position and the closed position. In the illustrated embodiment, the cradle78includes openings80, and circular protrusions82of the ball76engage the respective openings80(e.g., forming a trunnion mounting arrangement). Accordingly, the ball76may rotate about the circular protrusions82between the open and closed positions. Each circular protrusion may be coupled to a body of the ball or integrally formed with the body of the ball. Furthermore, in the illustrated embodiment, each circular protrusion82has a slot84, and a slider86is disposed within the slot84. Each slot84enables the respective slider86to translate, and rotation of each slider86relative to the respective slot84is substantially blocked by contact between the slider86and the material of the respective circular protrusion82forming the slot84. In addition, an actuation pin88is coupled to (e.g., integrally formed with) each slider86and configured to engage an opening90of an operator92.

Movement of the operator92in the first translational direction40drives the actuation pins88to rotate the ball76in the first rotational direction42from the open position to the illustrated closed position. In addition, movement of the operator92in the second translational direction44drives the actuation pins88to rotate the ball76in the second rotational direction46from the closed position to the open position. The slots84enable lateral movement of the respective actuation pins88as the operator92moves in the first and second translational directions. In the illustrated embodiment, a bushing94is disposed about each actuation pin88, such that the bushing94is disposed between the actuation pin88and the respective opening90in the operator92. The bushings94may reducing the friction between the actuation pins and the operator, thereby reducing the force sufficient to drive the operator along the longitudinal axis64. While a single bushing is disposed about each actuation pin in the illustrated embodiment, in other embodiments, the bushing may be omitted from at least one actuation pin and/or multiple bushings may be disposed about at least one actuation pin. In addition, in certain embodiments, one or more bearings may be disposed about at least one actuation pin (e.g., alone or in combination with one or more bushings). While the actuation pins are coupled to respective sliders in the illustrated embodiment, in other embodiments, the actuation pins may be fixed to the ball and disposed within slots in the operator. The slots in the operator may enable the lateral movement of the actuation pins as the operator moves in the translational directions.

The operator92may be driven to move in the translational directions by any suitable device(s), such as one or more hydraulic pistons, one or more pneumatic pistons, one or more electromechanical actuators, other suitable type(s) of actuator(s), or a combination thereof. Furthermore, in certain embodiments, a spring (e.g., compression spring) may urge the operator to move in the first translational direction40, thereby urging the ball76to rotate toward the closed position. The spring may provide sufficient force to drive the ball to the closed position in response to interruption in operation of the device(s) configured to drive the operator to translate. In such embodiments, the ball valve assembly is considered a failsafe closed ball valve assembly. However, in other embodiments, the ball valve assembly may be a failsafe open ball valve assembly, a fail-as-is ball valve assembly, or any other suitable type of ball valve assembly.

In the illustrated embodiments, a seal retainer96is positioned on an opposite side of the ball76from the cradle78. In certain embodiments, the seal retainer96is urged toward the ball76along the second translational direction44by a spring and/or fluid pressure. A seal may be coupled to the seal retainer96(e.g., at an end of a fluid passage through the seal retainer) and engaged with the ball76while the ball is in the closed position. Contact between the seal and the ball blocks fluid flow through the ball valve assembly while the ball is in the closed position.

In the illustrated embodiment, a bearing98is disposed about each circular protrusion82, such that the bearing98is disposed between the circular protrusion82and the cradle78. The bearings98are configured to reduce rotational resistance, thereby facilitating rotation of the ball76between the open and closed position. In the illustrated embodiment, each bearing98is a ball bearing including an outer race non-rotatably coupled to the cradle78(e.g., via a press-fit connection, via a threaded connection, via a pinned connection, via a welded connection, via an adhesive connection, via another suitable connection, or a combination thereof). In addition, each bearing98includes an inner race non-rotatably coupled to the respective circular protrusion82(e.g., via a press-fit connection, via a threaded connection, via a pinned connection, via a welded connection, via an adhesive connection, via another suitable connection, or a combination thereof). Each bearing98also includes bearing balls disposed between the races to facilitate rotation of the inner race/ball relative to the outer race/cradle. In certain embodiments, wiper seal(s) may be positioned at one or more respective bearings to substantially block dirt and/or debris from entering the respective bearing(s).

While ball bearings are employed within the illustrated embodiment, in other embodiments, other suitable bearing(s) and/or bushing(s) may be disposed about at least one circular protrusion to facilitate rotation of the ball relative to the cradle. For example, while a single bearing is disposed about each circular protrusion in the illustrated embodiment, in other embodiments, multiple bearings and/or one or more bushings (e.g., alone, in combination with a single bearing, or in combination with multiple bearings) may be disposed about at least one circular protrusion. In certain embodiments, adjustment nut(s) may be used to couple the bearing(s) to each circular protrusion with sufficient force to substantially reduce or eliminate the possibility of disengagement of the bearing(s). Furthermore, in certain embodiments, no bearings and no bushings may be disposed about at least one circular protrusion. In such embodiments, a lubricant may be disposed about the circular protrusion(s) to facilitate rotation of the ball relative to the cradle. A lubricant may also be employed within the embodiments having one or more bearings (e.g., within the bearing(s)) and/or one or more bushings (e.g., on an inner surface of each bushing and/or on an outer surface of each bushing).

Because each slot84is disposed within a respective circular protrusion82, the diameter of the circular protrusions may be increased (e.g., as compared to an embodiment in which the slots/actuation pins are positioned at another location on the ball), thereby increasing the strength of the circular protrusions (e.g., as compared to a ball having smaller circular protrusion). The strong circular protrusions may enable the maximum fluid pressure rating of the ball valve assembly to be increased. In addition, the bearings disposed about the circular protrusions facilitate rotation of the ball at the maximum fluid pressure rating of the ball valve assembly. Furthermore, the openings80are positioned to establish a separation distance between the ball and the ball-facing surface of the cradle (e.g., while the ball valve assembly is operating at the maximum fluid pressure rating), thereby reducing resistance to rotation of the ball.

FIG.6is an exploded perspective view of a portion of the ball support and actuation assembly74ofFIG.5. In the illustrated embodiment, the cradle78includes a first portion100forming a first portion of each opening80, and the cradle78includes a second portion102forming a second portion of each opening80. Accordingly, while the second portion102is coupled to the first portion100, the circular protrusions82are captured within the openings80formed between the two portions. In the illustrated embodiment, the second portion102is coupled to the first portion100by fasteners104. However, in other embodiments, the second portion may be coupled to the first portion by any other suitable connection system. Furthermore, in certain embodiments, the openings80within the cradle78may be formed by any other suitable structure of the cradle78.

FIG.7is a cross-sectional perspective view of an embodiment of an operator assembly106that may be employed within the ball valve assembly ofFIG.1, in which the operator assembly106is in an open state. In the illustrated embodiment, the operator assembly106includes a first operator108and a second operator110. The first operator108has a first opening112configured to receive a first actuation pin113, and the second operator110has a second opening114configured to receive a second actuation pin115. The actuation pins may be positioned on opposite radial sides of the axis of rotation of the ball. In certain embodiments, the ball, such as the ball disclosed above with reference toFIGS.2-4or the ball disclosed above with reference toFIGS.5-6, includes at least one slot configured to receive two sliders. Each slider is configured to move independently within the slot. In addition, the first actuation pin, which is received by the first opening of the first operator, is coupled to (e.g., integrally formed with) the first slider, and the second actuation pin, which is received by the second opening of the second operator, is coupled to (e.g., integrally formed with) the second slider. In certain embodiments, the ball may include two slots, and one first slider and one second slider may be disposed within each slot. In such embodiments, the first operator may include two first openings positioned on opposite sides of the ball along the axis of rotation of the ball, in which each first opening is configured to receive a respective first actuation pin, and the second operator may include two second openings positioned on opposite sides of the ball along the axis of rotation of the ball, in which each second opening is configured to receive a respective second actuation pin.

In the illustrated embodiment, a portion of the second operator110is disposed within a passage of the first operator108. The outer dimensions of the portion of the second operator disposed within the passage of the first operator may be substantially equal to the inner dimensions of the passage of the first operator, thereby reducing radial movement of the second operator relative to the first operator. While the portion of the second operator disposed within the passage of the first operator and the passage of the first operator having substantially circular cross-sections in the illustrated embodiment, in other embodiment, the portion of the second operator and the passage of the first operator may have any other suitable cross-sectional shape (e.g., polygonal, etc.). Furthermore, while the portion of the second operator is disposed within the passage of the first operator in the illustrated embodiment, in other embodiments, a portion of the first operator may be disposed within a passage of the second operator. Furthermore, in the illustrated embodiment, each opening is formed within an extension of the respective operator. However, in other embodiments, at least one opening may be formed within another suitable portion of the respective operator.

While the operator assembly106is in the illustrated open state, the respective ball is in the open position. To transition the ball to the closed position, the operators are moved toward one another. For example, movement of the first operator108in the second translational direction44drives the first actuation pin(s) to rotate the ball toward the closed position. In addition, movement of the second operator110in the first translational direction40drives the second actuation pin(s) to rotate the ball toward the closed position. The slot(s) within the ball enable the lateral movement of the respective actuation pins as the operators move toward one another. In certain embodiments, the first operator108may be driven to move in the second translational direction44by hydraulic fluid pressure applied to a piston116of the first operator108. In addition, the second operator110may be driven to move in the first translational direction40by hydraulic fluid pressure applied to a piston118of the second operator110. Because hydraulic fluid pressure is applied to two pistons to drive the ball to the closed position, significantly more torque may be applied to the ball than a configuration having a single piston. As a result, the ball may apply additional force to cut a line (e.g., wireline, coil tubing, etc.) extending through the fluid passage of the ball while the ball is in the open position. In addition, if operation of one operator is interrupted (e.g., due to an interruption in hydraulic fluid flow), and the operator is free to move, the other operator may drive the ball to rotate to the closed position. While hydraulic fluid pressure is used to drive the operator assembly106to the closed state in the illustrated embodiment, in other embodiments, at least one operator may be driven toward the closed state by another suitable actuation fluid. For example, in certain embodiments, at least one operator may be driven toward the closed state by pneumatic pressure applied to the respective piston. Furthermore, in certain embodiments, at least one operator may be driven to the closed state by one or more actuator(s), such as electrically-operated actuator(s), pneumatically-operated actuator(s), hydraulically-operated actuator(s), or a combination thereof.

Furthermore, in certain embodiments, a first spring (e.g., compression spring) may urge the first operator108to move in the second translational direction44, and a second spring (e.g., compression spring) may urge the second operator110to move in the first translational direction40, thereby urging the operators toward one another, such that the ball is urged toward the closed position. In certain embodiments, each spring may provide sufficient force to drive the ball to the closed position in response to an interruption in fluid flow to the pistons/operation of the actuator(s). Accordingly, the respective ball valve assembly is a failsafe closed ball valve assembly. In addition, because each spring is configured to provide sufficient force to rotate the ball to the closed position, the ball valve assembly may maintain the failsafe closed functionality even if the force provided by one spring is reduced (e.g., in response to fatigue, etc.). Furthermore, the fatigue experienced by each spring may be reduced, as compared to utilizing a single spring to drive the operator assembly to the closed state. While utilizing two springs to drive the operator assembly to the closed state is disclosed above, in certain embodiments, a single spring may be used to drive at least one operator to the closed state, or one or more springs may be used to drive the operators to the open state (e.g., forming a failsafe open ball valve assembly). Furthermore, any suitable type(s) of spring(s) (e.g., coil spring(s), leaf spring(s), pneumatic spring(s), hydraulic spring(s), electromagnetic spring(s), etc.) may be utilized to urge at least one operator in a desired direction.

FIG.8is a cross-sectional view of the operator assembly106ofFIG.7, in which the operator assembly106is in a closed state. While the operator assembly106is in the illustrated closed state, the respective ball is in the closed position. To transition the ball to the open position, the operators are moved away from one another. For example, movement of the first operator108in the first translational direction40drives the first actuation pin(s) to rotate the ball toward the open position. In addition, movement of the second operator110in the second translational direction44drives the second actuation pin(s) to rotate the ball toward the open position. The slot(s) within the ball enable the lateral movement of the respective actuation pins as the operators move away from one another. Furthermore, while the operator assembly106is in the closed state, the operators engage one another, thereby blocking further rotation of the ball. However, in other embodiments, another suitable stop assembly/device may be used to block rotation of the ball past the closed position.

In certain embodiments, the first operator108may be driven to move in the first translational direction40by hydraulic fluid pressure applied to the piston116of the first operator108. In addition, the second operator110may be driven to move in the second translational direction44by hydraulic fluid pressure applied to the piston118of the second operator110. The pressurized hydraulic fluid may be supplied to a chamber120(e.g., annular chamber) extending between the piston116of the first operator108and the piston118of the second operator110. However, in other embodiments, the pressurized hydraulic fluid may be supplied to multiple chambers positioned between the pistons (e.g., one chamber for each piston). In certain embodiments, pressurized fluid from the well bore may also be directed to a region122between the operators, thereby further urging the operators to move away from one another. Because hydraulic fluid pressure is applied to two pistons to drive the ball to the open position, significantly more torque may be applied to the ball than a configuration having a single piston. As a result, the static friction between the ball and respective contact surface(s) may be overcome by the torque applied by the operator assembly, thereby facilitating the transition between the closed position and the open position of the ball. In addition, if operation of one operator is interrupted (e.g., due to an interruption in hydraulic fluid flow), and the operator is free to move, the other operator may drive the ball to rotate to the open position. In certain embodiments, a first hydraulic line may extend to the chamber120, a second hydraulic line may provide pressurized hydraulic fluid to urge the first operator108to move in the second translational direction44, and a third hydraulic line may provide pressurized hydraulic fluid to urge the second operator110to move in the first translational direction40. However, in other embodiments, any other suitable hydraulic line configuration may be used to control movement of the operators. While hydraulic fluid pressure is used to drive the operator assembly106to the open state in the illustrated embodiment, in other embodiments, at least one operator may be driven toward the open state by another suitable actuation fluid. For example, in certain embodiments, at least one operator may be driven toward the open state by pneumatic pressure applied to the respective piston. Furthermore, in certain embodiments, at least one operator may be driven to the open state by one or more actuator(s), such as electrically-operated actuator(s), pneumatically-operated actuator(s), hydraulically-operated actuator(s), or a combination thereof.

The operator assembly disclosed herein with reference toFIGS.7-8may be used with the ball support and actuation assembly disclosed above with reference toFIGS.2-4and with the ball support and actuation assembly disclosed above with reference toFIGS.5-6. For example, with regard to the ball support and actuation assembly disclosed above with reference toFIGS.5-6, two sliders may be disposed within each slot, and an actuation pin may be coupled to each slider and configured to engage a corresponding opening of a respective operator. Furthermore, in embodiments of the ball support and actuation assembly ofFIGS.5-6in which the actuation pin(s) are fixed to the ball, two actuation pins may be fixed to at least one side of the ball. In addition, each actuation pin may be engaged with a corresponding opening of a respective operator, and the corresponding openings may be slot-shaped to accommodate lateral movement of the actuation pins. With regard to the ball support and actuation assembly disclosed above with reference toFIGS.2-4, two actuation pins may be fixed to at least one side of the ball. In addition, each actuation pin may be engaged with a corresponding opening of a respective operator, and the corresponding openings may be slot-shape to accommodate lateral movement of the actuation pins. Furthermore, in embodiments of the ball support and actuation assembly ofFIGS.2-4in which the actuation pin(s) are coupled to slider(s) disposed within respective slot(s) in the ball, two sliders may be disposed within each slot, and an actuation pin may be coupled to each slider and configured to engage a corresponding opening of a respective operator.

While the operator assembly is in the open state while the operators are farther apart and in the closed state while the operators are closer together in the illustrated embodiment, in other embodiments, the operator assembly may be in the closed state while the operators are farther apart and in the open state while the operators are closer together. In such embodiments, a compression spring may be disposed between the operators to urge the operators away from one another, thereby establishing a failsafe closed ball valve assembly. Furthermore, pressurized fluid from the well bore may be directed to the region between the operators, thereby further urging the operators to move away from one another (e.g., to further enhance the failsafe closed functionality of the respective ball valve assembly).

FIG.9is a cross-sectional perspective view of another embodiment of an operator assembly124that may be employed within the ball valve assembly ofFIG.1, in which the operator assembly is in a closed state. In the illustrated embodiment, the operator assembly124includes a first operator126and a second operator128. As illustrated, the first operator126and the second operator128are disposed within a housing130and configured to move relative to the housing130. The first operator126has a first opening132configured to receive a first actuation pin133, and the second operator128has a second opening134configured to receive a second actuation pin135. The actuation pins may be positioned on opposite radial sides of the axis of rotation of the ball. In certain embodiments, the ball, such as the ball disclosed above with reference toFIGS.2-4or the ball disclosed above with reference toFIGS.5-6, includes at least one slot configured to receive two sliders. Each slider is configured to move independently within the slot. In addition, the first actuation pin, which is received by the first opening of the first operator, is coupled to (e.g., integrally formed with) the first slider, and the second actuation pin, which is received by the second opening of the second operator, is coupled to (e.g., integrally formed with) the second slider. In certain embodiments, the ball may include two slots, and one first slider and one second slider may be disposed within each slot. In such embodiments, the first operator may include two first openings positioned on opposite sides of the ball along the axis of rotation of the ball, in which each first opening is configured to receive a respective first actuation pin, and the second operator may include two second openings positioned on opposite sides of the ball along the axis of rotation of the ball, in which each second opening is configured to receive a respective second actuation pin.

In the illustrated embodiment, each opening is formed within an extension of the respective operator. In addition, each operator includes recess(es) configured to receive the extension(s) of the other operator, thereby facilitating movement of the operators to the open state. While each opening is formed within an extension in the illustrated embodiment, in other embodiments, at least one opening may be formed within another suitable portion of the respective operator. Furthermore, in the illustrated embodiment, the structure of the first operator is the same as the structure of the second operator. Accordingly, a single operator may be used as either the first operator or the second operator. As a result, the design and/or manufacturing cost of the operator assembly may be reduced (e.g., as compared to an operator assembly that include different configurations for the first and second operators). In addition, the forces applied to operators by friction and pressurized fluids may be substantially equal, thereby facilitating balanced operation of the valve assembly. However, in other embodiments, the first and second operators may be different from one another.

While the operator assembly124is in the illustrated closed state, the respective ball is in the closed position. To transition the ball to the open position, the operators are moved toward one another. For example, movement of the first operator126in the second translational direction44drives the first actuation pin(s) to rotate the ball toward the open position. In addition, movement of the second operator128in the first translational direction40drives the second actuation pin(s) to rotate the ball toward the open position. The slot(s) within the ball enable the lateral movement of the respective actuation pins as the operators move toward one another. In certain embodiments, the first operator126may be driven to move in the second translational direction44by hydraulic fluid pressure applied to a piston136of the first operator126. In addition, the second operator128may be driven to move in the first translational direction40by hydraulic fluid pressure applied to a piston138of the second operator128. Because hydraulic fluid pressure is applied to two pistons to drive the ball to the open position, significantly more torque may be applied to the ball than a configuration having a single piston. As a result, the static friction between the ball and respective contact surface(s) may be overcome by the torque applied by the operator assembly, thereby facilitating the transition between the closed position and the open position of the ball. In addition, because the cross-sectional areas of the pistons are substantially equal to one another, the torques applied by the operators to the ball may be substantially equal to one another. Furthermore, if operation of one operator is interrupted (e.g., due to an interruption in hydraulic fluid flow), and the operator is free to move, the other operator may drive the ball to rotate to the open position. While hydraulic fluid pressure is used to drive the operator assembly124to the open state in the illustrated embodiment, in other embodiments, at least one operator may be driven toward the open state by another suitable actuation fluid. For example, in certain embodiments, at least one operator may be driven toward the open state by pneumatic pressure applied to the respective piston. Furthermore, in certain embodiments, at least one operator may be driven to the open state by one or more actuator(s), such as electrically-operated actuator(s), pneumatically-operated actuator(s), hydraulically-operated actuator(s), or a combination thereof.

FIG.10is a cross-sectional view of the operator assembly124ofFIG.9, in which the operator assembly is in an open state. While the operator assembly124is in the illustrated open state, the respective ball is in the open position. To transition the ball to the closed position, the operators are moved away from one another. For example, movement of the first operator126in the first translational direction40drives the first actuation pin(s) to rotate the ball toward the closed position. In addition, movement of the second operator128in the second translational direction44drives the second actuation pin(s) to rotate the ball toward the closed position. The slot(s) within the ball enable the lateral movement of the respective actuation pins as the operators move away from one another. Furthermore, while the operator assembly124is in the open state, the operators engage one another, thereby blocking further rotation of the ball. However, in other embodiments, another suitable stop assembly/device may be used to block rotation of the ball past the open position.

In certain embodiments, the first operator126may be driven to move in the first translational direction40by hydraulic fluid pressure applied to the piston136of the first operator126. In addition, the second operator128may be driven to move in the second translational direction44by hydraulic fluid pressure applied to the piston138of the second operator128. The pressurized hydraulic fluid may be supplied to a first chamber140(e.g., annular chamber) extending between the piston136of the first operator126and the housing130, and the pressurized hydraulic fluid may be supplied to a second chamber142(e.g., annular chamber) extending between the piston138of the second operator128and the housing130. However, in other embodiments, the pressurized hydraulic fluid may be supplied to a single chamber positioned between the pistons (e.g., having a portion that extends through the housing). Because hydraulic fluid pressure is applied to two pistons to drive the ball to the closed position, significantly more torque may be applied to the ball than a configuration having a single piston. As a result, the ball may apply additional force to cut a line (e.g., wireline, coil tubing, etc.) extending through the fluid passage of the ball while the ball is in the open position. In addition, because the cross-sectional areas of the first and second chambers are substantially equal to one another, the torques applied by the operators to the ball may be substantially equal to one another. Furthermore, if operation of one operator is interrupted (e.g., due to an interruption in hydraulic fluid flow), and the operator is free to move, the other operator may drive the ball to rotate to the closed position. In certain embodiments, a first hydraulic line may extend to the first chamber140, a second hydraulic line may extend to the second chamber142, a third hydraulic line may provide pressurized hydraulic fluid to urge the first operator126to move in the second translational direction44, and a fourth hydraulic line may provide pressurized hydraulic fluid to urge the second operator128to move in the first translational direction40. However, in other embodiments, any other suitable hydraulic line configuration may be used to control movement of the operators. While hydraulic fluid pressure is used to drive the operator assembly124to the closed state in the illustrated embodiment, in other embodiments, at least one operator may be driven toward the closed state by another suitable actuation fluid. For example, in certain embodiments, at least one operator may be driven toward the closed state by pneumatic pressure applied to the respective piston. Furthermore, in certain embodiments, at least one operator may be driven to the closed state by one or more actuator(s), such as electrically-operated actuator(s), pneumatically-operated actuator(s), hydraulically-operated actuator(s), or a combination thereof.

Furthermore, in certain embodiments, a first compression spring may be disposed between the piston136of the first operator126and the housing130, and a second compression spring may be disposed between the piston138of the second operator128and the housing130. The first compression spring may urge the first operator126to move in the first translational direction40, and the second compression spring may urge the second operator128to move in the second translational direction44, thereby urging the operators away from one another, such that the ball is urged toward the closed position. In certain embodiments, each compression spring may provide sufficient force to drive the ball to the closed position in response to an interruption in fluid flow to the pistons/operation of the actuator(s). Accordingly, the respective ball valve assembly is a failsafe closed ball valve assembly. In addition, because each compression spring is configured to provide sufficient force to rotate the ball to the closed position, the ball valve assembly may maintain the failsafe closed functionality even if the force provided by one compression spring is reduced (e.g., in response to fatigue, etc.). Furthermore, the fatigue experienced by each compression spring may be reduced, as compared to utilizing a single spring to drive the operator assembly to the closed state. In certain embodiments, pressurized fluid from the well bore may be directed to a region144between the operators, thereby further urging the operators to move away from one another (e.g., to further enhance the failsafe closed functionality of the respective ball valve assembly). While utilizing two compression springs to drive the operator assembly to the closed state is disclosed above, in certain embodiments, a single compression spring may be used to drive at least one operator to the closed state, or one or more compression springs may be used to drive the operators to the open state (e.g., forming a failsafe open ball valve assembly). Furthermore, while compression spring(s) are disclose above, any other suitable type(s) of spring(s) (e.g., coil spring(s), leaf spring(s), pneumatic spring(s), hydraulic spring(s), electromagnetic spring(s), etc.) may be utilized (e.g., alone or in combination with the compression spring(s)) to urge at least one operator in a desired direction.

The operator assembly disclosed herein with reference toFIGS.9-10may be used with the ball support and actuation assembly disclosed above with reference toFIGS.2-4and with the ball support and actuation assembly disclosed above with reference toFIGS.5-6. For example, with regard to the ball support and actuation assembly disclosed above with reference toFIGS.5-6, two sliders may be disposed within each slot, and an actuation pin may be coupled to each slider and configured to engage a corresponding opening of a respective operator. Furthermore, in embodiments of the ball support and actuation assembly ofFIGS.5-6in which the actuation pin(s) are fixed to the ball, two actuation pins may be fixed to at least one side of the ball. In addition, each actuation pin may be engaged with a corresponding opening of a respective operator, and the corresponding openings may be slot-shaped to accommodate lateral movement of the actuation pins. With regard to the ball support and actuation assembly disclosed above with reference toFIGS.2-4, two actuation pins may be fixed to at least one side of the ball. In addition, each actuation pin may be engaged with a corresponding opening of a respective operator, and the corresponding openings may be slot-shape to accommodate lateral movement of the actuation pins. Furthermore, in embodiments of the ball support and actuation assembly ofFIGS.2-4in which the actuation pin(s) are coupled to slider(s) disposed within respective slot(s) in the ball, two sliders may be disposed within each slot, and an actuation pin may be coupled to each slider and configured to engage a corresponding opening of a respective operator.

While the operator assembly is in the closed state while the operators are spaced farther apart and in the open state while the operators are closer together in the illustrated embodiment, in other embodiments, the operator assembly may be in the open state while the operators are spaced farther apart and in the closed state while the operators are closer together. In such embodiments, opposing compression springs may urge the operators toward one another, thereby establishing a failsafe closed ball valve assembly. In certain embodiments, each spring is configured to provide sufficient force to rotate the ball to the closed position. Accordingly, the ball valve assembly may maintain the failsafe closed functionality even if the force provided by one spring is reduced (e.g., in response to fatigue, etc.). Furthermore, while the operator assemblies ofFIGS.7-10are disclosed above with reference to driving a ball between an open position and a closed position, each operator assembly may also be used to drive another suitable valve element, such as a disc of a butterfly valve, between the open and closed positions.