CROSS-REFERNCE TO RELATED APPLICATION

This Application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 62/573,296 filed on October 17, 2017, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

This disclosure relates to stuffing boxes used in oilfield operations, and, in particular, to pollution control valves for stuffing boxes.

BACKGROUND OF THE DISCLOSURE In oilfield operations, stuffing boxes are used to form a seal between the wellhead and piping passing through the wellhead to prevent leakage of wellbore fluids between the wellhead and the piping. For example, progressive cavity pump systems include a drive shaft (sometimes referred to as a "polished rod") that drives rotation of a drive string (sometimes referred to as a "sucker rod"), which, in turn, drives a progressing cavity pump located at the bottom of the wellbore to produce wellbore fluids to the surface through the wellhead. The drive shaft of a progressive cavity pump system passes through a stuffing box that is connected to the wellhead to form a seal between the wellhead and the drive shaft.

A pollution control valve is sometimes provided within the flow tree of a wellhead pump system to prevent a failure of the drive shaft from allowing wellbore fluids to flow up through the stuffing box and thereby spill out into the environment. At least some conventional pollution control valves use a spring-loaded flap that automatically closes when the drive shaft fails. But, the spring-loaded flap is continually forced against the drive shaft during operation of the pump system, which exerts wear on the drive shaft that can cause leakage (e.g., at the stuffing box, etc.) and/or premature failure of the drive shaft. Some conventional pollution control valves attempt to mitigate the wear on the drive shaft using a plastic wear pad on the flap, but the drive shaft still experiences wear that over time can allow pollutive wellbore fluids to leak.

SUMMARY

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features or essential features of the claimed subject matter. Nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

In a first aspect, a pollution control valve is provided for a stuffing box of a pump system. The pollution control valve includes a body having an internal bore configured to receive a drive shaft of the pump system. The pollution control valve includes a sealing sleeve held within the internal bore of the body. The sealing sleeve includes a passage extending through the sealing sleeve. The sealing sleeve is moveable between an open position and a closed position that prevents fluid from flowing through the internal bore. The passage is aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve. The pollution control valve includes an actuator configured to bias the sealing sleeve toward the closed position.

In some embodiments, the sealing sleeve is held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore.

In some embodiments, the bias of the actuator is configured to move the sealing sleeve from the open position to the closed position upon the drive shaft exiting the internal bore.

In some embodiments, the sealing sleeve is configured to rotate between the open position and the closed position. In some embodiments, the sealing sleeve includes a bearing held within the passage of the sealing sleeve.

In some embodiments, the sealing sleeve includes a bearing held within the passage of the sealing sleeve. The bearing includes balls held by a retaining ring. The balls are configured to rotate in response to at least one of rotational or reciprocal motion of the drive shaft within the internal bore.

In some embodiments, the actuator includes a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

In some embodiments, the sealing sleeve includes a curved exterior shape.

In some embodiments, the sealing sleeve includes a spherical segment shape.

In a second aspect, a stuffing box assembly is provided for a pump system. The stuffing box assembly includes a stuffing box configured to be connected to a well head. The stuffing box is configured to receive a drive shaft of the pump system through the stuffing box. The stuffing box assembly includes a pollution control valve. The pollution control valve includes a body having an internal bore. The body is connected to the stuffing box such that the drive shaft is configured to extend through the internal bore. The pollution control valve includes a sealing sleeve held within the internal bore of the body. The sealing sleeve includes a passage extending through the sealing sleeve. The sealing sleeve is moveable between an open position and a closed position that prevents fluid from flowing through the internal bore. The passage is aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve. The pollution control valve includes an actuator configured to bias the sealing sleeve toward the closed position.

In some embodiments, the sealing sleeve of the pollution control valve is held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore. In some embodiments, the bias of the actuator of the pollution control valve is configured to move the sealing sleeve from the open position to the closed position upon the drive shaft exiting the internal bore.

In some embodiments, the sealing sleeve of the pollution control valve is configured to rotate between the open position and the closed position.

In some embodiments, the sealing sleeve of the pollution control valve includes a bearing held within the passage of the sealing sleeve.

In some embodiments, the sealing sleeve of the pollution control valve includes a bearing held within the passage of the sealing sleeve. The bearing includes balls held by a retaining ring. The balls are configured to rotate in response to at least one of rotational or reciprocal motion of the drive shaft within the internal bore.

In some embodiments, the actuator of the pollution control valve includes a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

In some embodiments, the sealing sleeve of the pollution control valve includes a curved exterior shape.

In some embodiments, the sealing sleeve of the pollution control valve includes a spherical segment shape.

In a third aspect, a pollution control valve is provided for a stuffing box of a pump system. The pollution control valve includes a body having an internal bore configured to receive a drive shaft of the pump system. The pollution control valve includes a sealing sleeve held within the internal bore of the body. The sealing sleeve includes a passage extending through the sealing sleeve. The sealing sleeve is moveable between an open position and a closed position that prevents fluid from flowing through the internal bore. The passage is aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve. The sealing sleeve is held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore. The sealing sleeve includes a spherical segment shape. The pollution control valve includes an actuator configured to bias the sealing sleeve toward the closed position.

In some embodiments, the actuator includes a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

Other aspects, features, and advantages will become apparent from the following detailed description when taken in conjunction with the accompanying drawings, which are a part of this disclosure and which illustrate, by way of example, principles of the inventions disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings facilitate an understanding of the various embodiments. FIG. 1 is a schematic view of an exemplary cavity pump system in an earth formation. FIG. 2 is a schematic view of an exemplary drive head of the cavity pump system shown in FIG. 1.

FIG. 3 is a cross-sectional view of a stuffing box assembly of the cavity pump system shown in FIG. 1 according to an exemplary embodiment.

FIG. 4 is a cross-sectional view of a pollution control valve of the stuffing box assembly shown in FIG. 3 according to an exemplary embodiment.

FIG. 5 is another cross-sectional view of the pollution control valve shown in FIG. 4 illustrating the pollution control valve in a closed position according to an exemplary embodiment.

FIG. 6 is a plan view of the pollution control valve shown in FIG. 4 and 5 illustrating the pollution control valve in an open position according to an exemplary embodiment. FIG. 7 is a plan view of the pollution control valve shown in FIGS. 4-6 illustrating the pollution control valve in the closed position shown in FIG. 5.

FIG. 8 is another cross-sectional view of the stuffing box assembly shown in FIG. 3 illustrating a failure of a drive shaft of the cavity pump system shown in FIG. 1.

FIG.9 is another cross-sectional view of the stuffing box assembly shown in FIG. 3 illustrating the pollution control valve shown in FIGS. 4-7 in the closed position shown in FIGS. 5 and 7.

Corresponding reference characters indicate corresponding parts throughout the drawings.

DETAILED DESCRIPTION Certain embodiments of the disclosure provide a pollution control valve is provided for a stuffing box of a pump system. The pollution control valve includes a body having an internal bore configured to receive a drive shaft of the pump system. The pollution control valve includes a sealing sleeve held within the internal bore of the body. The sealing sleeve includes a passage extending through the sealing sleeve. The sealing sleeve is moveable between an open position and a closed position that prevents fluid from flowing through the internal bore. The passage is aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve. The pollution control valve includes an actuator configured to bias the sealing sleeve toward the closed position.

REVISE - Certain embodiments of the disclosure provide a pollution control valve that reduces the wear experienced by a drive shaft during operation of a pump system. Certain embodiments of the disclosure provide a pollution control valve that reduces leakage of wellbore fluid. Certain embodiments of the disclosure provide a pollution control valve that extends the life of a drive shaft of a pump system. Certain embodiments of the disclosure provide a pollution control valve that automatically closes upon the failure of the drive shaft of a pump system. Certain embodiments of the disclosure provide an automatic pollution control valve that is independent of the flow and pressure of the wellbore fluid of a wellbore.

FIG. 1 illustrates an exemplary cavity pump system 10 in an earth formation (e.g., for use in an oilfield, etc.). The pump system 10 includes a drive head 12, a wellhead frame 14, a stuffing box 16, an electric motor 18, and a drive system 20 (e.g., a belt and sheave drive system, etc.). The drive head 12, the wellhead frame 14, the stuffing box 16, the electric motor 18, and the drive system 20 are mounted on a flow tee 22. In the example, of FIG. 1 , the flow tee 22 includes a blowout preventer 24 which is, in turn, mounted on a wellhead 26 of a wellbore 28. The drive head 12 supports and drives a drive shaft 30, which is sometimes referred to as a "polished rod". More particularly, the drive shaft 30 is supported by a clamp 32 that engages an output shaft 34 of the drive head 12 to drive rotation of the drive shaft 30. The drive shaft 30 drives rotation of a drive string 36, which is sometimes referred to as a "sucker rod". The drive string 36 drives a progressing cavity pump 38 located at the bottom of the wellbore 28 to produce well fluids to the surface through the wellhead 26. The drive shaft 30 extends through the stuffing box 16 such that the stuffing box 16 provides a seal between the drive shaft 30 and the wellhead 26 to prevent wellbore fluid (e.g. , oil, gas, etc.) from leaking out where the drive shaft 30 transitions from the drive head 12 to the flow tee 22 and thereby the wellhead 26.

In the example of FIG. 1 , the wellhead frame 14 of the drive head 12 is open sided to expose the drive shaft 30 and thereby enable a service crew to install a safety clamp (not shown) on the drive shaft 30, perform maintenance on stuffing box 16, and/or the like. FIG. 2 illustrates another example of a drive head 40 for use with the cavity pump system 10 (i.e., corresponding to the portion of the system 10 above the dashed line 42). The drive head 40 includes a stuffing box 44 mounted to the drive head 40, as is shown in FIG. 2. Because the stuffing box 44 is integrated into the drive head 40, the pump system 10 does not include a wellhead frame.

FIG. 3 illustrates an exemplary embodiment of a stuffing box assembly 100 that can be used with the cavity pump system 10 shown in FIG. 1. For example, the stuffing box assembly 100 can be used in place of the stuffing box 16 shown in FIG. 1 or the stuffing box 44 shown in FIG. 2. The stuffing box assembly 100 includes a stuffing box 102 and a pollution control valve 104 that is configured to provide pollution protection for the stuffing box 102, as will be described in more detail below. The stuffing box 102 includes a housing 106 that extends a length from an end portion 108 to an opposite end portion 110. The housing 106 includes an internal passage 112 that extends through the length of the housing 106 along a central longitudinal axis 1 14.

The housing 106 of the stuffing box 102 is configured to be connected between a wellhead (e.g., the wellhead 26 shown in FIG. 1 , etc.) and a drive head (e.g., the drive head 12 shown in FIG. 1 , the drive head 40 shown in FIG. 2, etc.) of a pump system (e.g., the cavity pump system 10 shown in FIG. 1, etc.) such that a drive shaft 116 of the pump system extends through the internal passage 112 of the housing 106 of the stuffing box 102, as is shown in FIG. 3. More particularly, the end portion 108 of the housing 106 is configured to be mounted, whether directly or indirectly, to the drive head of the pump system such that the internal passage 1 12 is aligned to receive the drive shaft 1 16 therein from the drive head. The end portion 110 of the housing 106 is configured to be mounted, whether directly or indirectly, to the wellhead of the pump system. For example, in the exemplary embodiment, the end portion 1 10 of the housing 106 is mounted directly to the pollution control valve 104 such that the housing 106 is mounted indirectly to the wellhead. The internal passage 1 12 of the housing 106 is aligned relative to the wellhead such that the drive shaft 1 16 extends outward from the internal passage 1 12 through any intervening component(s) (e.g., the pollution control valve 104, the flow tee 22 shown in FIG. 1 , the blowout preventer 24 shown in FIG. 1, etc.) and into the wellhead. The housing 106 of the stuffing box 102 holds one or more sealing components 1 18 within the internal passage 1 12 that provide a fluid seal with the drive shaft 1 16 to prevent wellbore fluid from flowing up through the internal passage 1 12 of the stuffing box 102.

As will be described in more detail below, the pollution valve assembly 104 is operatively connected to the stuffing box 102 to provide a valve that automatically closes upon failure of the drive shaft 1 16 to prevent wellbore fluid from flowing up through the stuffing box 102 and spilling out into the environment. The pollution control valve 104 includes a body 120 that extends a length from an end portion 122 to an opposite end portion 124. The body 120 includes an internal bore 126 that extends through the length of the body 120 along a central longitudinal axis 128.

In the exemplary embodiment, the pollution control valve 104 is configured to be operatively connected between the stuffing box 102 and the wellhead of the pump system. More particularly, the end portion 122 of the body 120 is configured to be mounted directly to the end portion 1 10 of stuffing box 102 such that the internal bore 126 is aligned with the internal passage 1 12 of the stuffing box 102 to receive the drive shaft 1 16 through the internal bore 126. The end portion 124 of the body 120 of the pollution control valve 104 is configured to be mounted, whether directly or indirectly, to the wellhead of the pump system. For example, the end portion 124 of the body 120 can be mounted directly to an intervening component (e.g. , the flow tee 22, the blowout preventer 24, etc.) such that the body 120 of the pollution control valve 104 is mounted indirectly to the wellhead. The internal bore 120 of the pollution control valve 104 is aligned relative to the wellhead such that the drive shaft 116 extends outward from the internal bore 126 through any intervening component(s) (e.g. , the flow tee 22, the blowout preventer 24, etc.) and into the wellhead. In another embodiment, the pollution control valve 104 is configured to be operatively connected between the stuffing box 102 and the drive head (e.g., the drive head 12, the drive head 40, etc.) of the pump system. More particularly, the end portion 124 of the body 120 can be mounted directly to the end portion 108 of the stuffing box 102 with the internal bore 126 aligned to receive the drive shaft 116 from the drive head and such that the drive shaft 1 16 extends outward from the pollution control valve 104 into the internal passage 1 12 of the stuffing box 102.

In the exemplary embodiment, the body 120 of the pollution control valve 104 is mounted to the housing 106 of the stuffing box 102 using a threaded connection, as can be seen in FIG. 3. But, additionally or alternatively the body 120 can be mounted to the housing 106 using any other suitable connection type, such as, but not limited to, using bolts, screws, a latch, a clip, a clamp, adhesive, bonding, and/or the like. In one example, the pollution control valve 104 is configured to be mounted to an existing stuffing box 102 to retrofit the stuffing box 102 with the pollution control valve 104. In some other embodiments, the body 120 of the pollution control valve 104 is integrally formed as a single unitary structure with the housing 102 of the stuffing box 102.

Referring now to FIGS. 4 and 5, the pollution control valve 104 includes a sealing sleeve 130 held within the internal bore 126 of the body 120. The sealing sleeve 130 includes a body 132 and a passage 134 extending a length through the body 132 along a central longitudinal axis 136. The body 132 of the sealing sleeve 130 is moveable within the internal bore 126 between an open position shown in FIG. 4 and a closed position shown in FIG. 5. In the open position, the passage 134 of the sealing sleeve 130 is aligned with the internal bore 126 such that the drive shaft 1 16 (not shown in FIG. 5) of the pump system (e.g., the cavity pump system 10 shown in FIG. 1 , etc.) is received through the passage 134 and thereby extends through the body 132 of the sealing sleeve 130, as can be seen in FIG. 4. More particularly, in the open position of the sealing sleeve 130, the drive shaft 1 16 extends into the internal bore 126 through the end portion 122 of the body 120 and along the internal bore 126 through the passage 134 of the sealing sleeve 130 and out of the internal bore 126 through the end portion 124 of the body 120.

The body 132 of the sealing sleeve 130 is configured to rotate within the internal bore

126 between the open and closed positions. In the closed position of the sealing sleeve 130 shown in FIG. 5, the body 132 of the sealing sleeve 130 is oriented such that the body 132 forms an obstruction that provides a fluid seal within the internal bore 126. More particularly, the exemplary embodiment of the pollution control valve 104 includes a seal 138 held within the internal bore 126 of the body 120. The seal 138 includes a shoulder 140 that has a complementary shape relative to at least a portion of the exterior of the body 132 of the sealing sleeve 130. In the closed position, the body 132 of the sealing sleeve 130 is sealingly engaged with the shoulder 140 of the seal 138 such that the body 132 provides a fluid tight obstruction within the internal bore 126, as can be seen in FIG. 5. Accordingly, the closed position of the sealing sleeve 130 prevents fluid from flowing through the internal bore 126 to thereby prevent wellbore fluid from flowing up through the internal passage 1 12 (FIG. 3) of the stuffing box 102 (FIG. 3) and spilling out into the environment.

The size, shape, and/or the like of the body 132 of the sealing sleeve 130 and the seal 138 can be selected to enable the sealing sleeve 130 and the seal 138 to sealingly engage each other such that the closed position of the sealing sleeve 130 provides a fluid-tight seal within the internal bore 126. In the exemplary embodiment, the body 132 of the sealing sleeve 130 has the exterior shape of a spherical segment (i.e., a sphere that has been cut by a pair of parallel planes) such that the sealing sleeve 130 is substantially similar to a ball valve. But, the exterior of the body 132 of the sealing sleeve 130 can have any curved shape that enables the sealing sleeve 130 to rotate between the open and closed positions and sealingly engage the seal 138 at the shoulder 140. For example, in other embodiments, the body 132 of the sealing sleeve 130 can have a more complex curved shape that includes two or more different radii of curvature (e.g., a smaller radius of curvature where the body 132 sealingly engages the shoulder 140 of the seal 138, etc.).

The seal 138 and the body 132 of the sealing sleeve 130 each can be fabricated from any material(s) that enable the sealing sleeve 130 and the seal 138 to sealingly engage each other with a fluid tight seal, such as, but not limited to, steel, tungsten carbide, another metal, an elastomeric material (e.g. , urethane, unsaturated rubber, saturated rubber, polysulfide rubber, resilin, elastin, polyisoprene, polybutadiene, chloroprene, butyl rubber, thermoplastics, elastolefin, etc.), polytetrafluoroethylene (PTFE, e.g., Teflon®, etc.), perfluoroalkoxy polymer resin (PFA, e.g., Teflon®, etc.), and/or the like. In some other embodiments, the pollution control valve 104 does not include the seal 138 and the internal bore 126 includes a shoulder that is shaped to be sealingly engaged (e.g., a metal to metal seal, etc.) by the body 132 of the sealing sleeve 130 in the closed position thereof.

The pollution control valve 104 includes one or more bearings 142 (not visible in FIG.

5) held within the passage 134 of the sealing sleeve 130. As will be described below, the bearing 142 can be configured to reduce the wear experienced by the drive shaft 1 16 during operation of the pump system by reducing the friction between the drive shaft 116 and the sealing sleeve 130. As best seen in FIG. 4, the exemplary embodiment of the bearing 142 includes a plurality of balls 144 (not visible in FIG. 5) held by a retaining ring 146 (not visible in FIG. 5). The balls 144 are held by the retaining ring 146 such that the balls 144 are configured to rotate about the retaining ring 146 in response to reciprocal motion of the drive shaft 1 16 along the central longitudinal axis 128 in the directions of the arrows 174 and 176. More particularly, each ball 144 is configured to rotate about an axis of rotation that extends approximately perpendicular to the central longitudinal axis 128 of the internal bore 126. In addition or alternatively, the balls 144 can be configured to rotate about axes of rotation that extend approximately parallel to the central longitudinal axis 128 of the internal bore 126 to rotate in response to rotational motion of the drive shaft 116 about the central longitudinal axis 128 during operation of the pump system. For example, the balls 144 can be held in a pocket of the body 132 of the sealing sleeve 130 such that the balls 144 can freely rotate in any direction within the pocket.

In some examples, the balls 144 are fabricated from, and/or include an external layer of (e.g., a coating, wrap, etc.), one or more materials that are softer than the drive shaft 116 to facilitate reducing the wear experienced by the drive shaft 116 during operation of the pump system, such as, but not limited to, tungsten carbide, another metal, an elastomeric material (e.g., urethane, unsaturated rubber, saturated rubber, polysulfide rubber, resilin, elastin, polyisoprene, polybutadiene, chloroprene, butyl rubber, thermoplastics, elastolefin, etc.), PTFE (e.g., Teflon®, etc.), PFA (e.g., Teflon®, etc.), and/or the like. Optionally, the balls 144 are fabricated from, and/or include an external layer of, one or more materials that is configured to reduce stiction and/or friction, such as, but not limited to, a material having a coefficient of friction less than approximately Ο. ΐμ, PTFE (e.g., Teflon®, etc.), PFA (e.g., Teflon®, etc.) rubber, and/or the like.

Although two are shown, the pollution control valve 104 can include any number of the bearings 142. In addition or alternatively to the bearing 142, the sealing sleeve 130 can include any other type of bearing that is configured to reduce friction between the sealing sleeve 130 and the drive shaft 116 during operation of the pump system, such as, but not limited to, a ball bearing, a roller bearing, a needle roller bearing, another type of rolling-element bearing, and/or the like.

The pollution control valve 104 includes an actuator 148 that is operatively connected to the sealing sleeve 130 to bias the sealing sleeve 130 toward the closed position shown in FIG. 5. The sealing sleeve 130 is held in the open position against the bias of the actuator 148 by the presence of the drive shaft 116 within the internal bore 126, as will be described below and should be apparent from FIG. 4. As will also be described below, upon failure of the drive shaft 116, the bias of the actuator 148 is configured to move (i.e., rotate) the sealing sleeve 130 from the open position shown in FIG. 4 to the closed position shown in FIG. 5.

In the exemplary embodiment, the actuator 148 includes an arm 150 and a weight 152. The arm 150 extends a length from an end portion 154 to an opposite end portion 156. The arm 150 is held by a bonnet 158. The end portion 154 of the arm 150 is fixedly connected to the sealing sleeve 130. In other embodiments, the end portion of the arm 150 is integrally formed with the body 132 of the sealing sleeve 130 as a single unitary structure. The weight 152 is connected to the end portion 156 of the arm 150. The arm 150 extends through a passage 160 of the bonnet 158 and is rotatable about an axis of rotation 162 within the passage 160.

Referring now to FIGS. 4 and 6, in the open position of the sealing sleeve 130, the weight 152 is held at anon-parallel angle relative to central longitudinal axis 128 of the internal bore 126 such that gravity acts to pull the weight 152 in the direction of the arrow 176 (not shown in FIG. 6). The weight 152 thereby biases the arm 150 to rotate the arm 150 in the direction of the arrow 174 toward the position of the arm 150 and the weight 152 shown in FIGS. 5 and 7. Accordingly, the weight 152 biases the sealing sleeve 130 toward the closed position shown in FIGS. 5 and 7 under the force of gravity. In the exemplary embodiment, the weight 152 extends at an approximately perpendicular angle relative to the central longitudinal axis 128 in the open position shown in FIGS. 4 and 6. But, the weight 152 can extend an any non-parallel angle relative to the central longitudinal axis 128 in the open position.

In addition or alternative to the weight 152, the arm 150 can be biased to the closed position of the sealing sleeve 130 using any other type of actuator, such as, but not limited to, an electric motor, a linear actuator (e.g., a ball screw, a lead screw, a rotary screw, another screw-type actuator, a hydraulic linear actuator, a pneumatic linear actuator, a solenoid, a servo, another type of linear actuator, etc.), a hydraulic actuator (e.g., a hydraulic pump system, etc.), a pneumatic actuator, a servo, and/or the like.

Although shown as being mounted to the body 120 of the pollution control valve 104 using bolts, additionally or alternatively the bonnet 158 can be mounted to the body 120 using any other suitable connection type, such as, but not limited to, a threaded connection, screws, a latch, a clip, a clamp, adhesive, bonding, and/or the like. In some other embodiments, the bonnet 158 is integrally formed as a single unitary structure with the body 120.

Referring again to FIG. 3, during operation of the pump system the drive shaft 1 16 extends through the internal passage 1 12 of the stuffing box 102 and through the internal bore 126 of the pollution control valve 104 to the wellhead. During operation, the drive shaft 116 reciprocates within the internal passage 1 12 and the internal bore 126 along the central longitudinal axes 114 and 128 in the directions of the arrows 174 and 176. The drive shaft 1 16 also rotates about the central longitudinal axes 114 and 128 during operation of the pump system. As shown in FIG. 3, the sealing sleeve 130 of the pollution control valve 104 is held in the open position against the bias of the actuator 148 by the presence of the drive shaft 116 within the internal bore 126. As described above, the balls 144 of the bearing 142 are configured to rotate in response to reciprocal motion of the drive shaft 1 16 along the central longitudinal axis 128.

The rotational movement of the balls 144, the curved shape of the balls 144, the optional external layer that is configured to reduce stiction and/or friction described above, and/or the softer (as compared to the drive shaft 116) material(s) of the balls 144 reduces the wear experienced by the drive shaft 1 16 during operation of the pump system. Moreover, the number of the balls 144 can be selected to spread the contact stresses resulting from contact between the drive shaft 116 and the bearing 142 over a larger surface area to thereby reduce the wear experienced by the drive shaft 1 16. For example, the pollution control valve 104 exerts less wear on the drive shaft 1 16 as compared to at least some known pollution control valves. By reducing the wear experienced by the drive shaft 1 16, the pollution control valve 104 reduces leakage of wellbore fluid (e.g., at the stuffing box 102, etc.), extends the life of the drive shaft 1 16, and/or the like.

Referring now to FIGS. 8 and 9, the pollution control valve 104 is configured to automatically close upon failure of the drive shaft 1 16. More particularly, when the drive shaft 1 16 fails (e.g., by breaking, being severed, etc.), the drive shaft 1 16 falls down through the internal passage 112 and the internal bore 126 into the wellbore and thereby exits the internal bore 126 of the pollution control valve 104. With the drive shaft 116 no longer present within the internal bore 126, the bias exerted by gravity on the weight 152 rotates the weight 152 and the arm 150 in the direction of the arrow 176 from the position of the weight 152 shown in FIG. 8 to the position of the weight 152 shown in FIG. 9. Rotation of the arm 150 in the direction of the arrow 176 to the position shown in FIG. 9 rotates the body 132 of the sealing sleeve 130 from the open position shown in FIG. 8 to the closed position shown in FIG. 9 wherein the sealing sleeve 130 prevents fluid from flowing up in the direction of the arrow 174 through the internal bore 126. Accordingly, upon failure of the drive shaft 1 16, the bias of the actuator 148 automatically closes the pollution control valve 104 to prevent wellbore fluid from flowing up in the direction of the arrow 174 through the internal passage 112 of the stuffing box 102 and thereby spilling out into the environment. The pollution control valve 104 thereby provides the pump system with pollution control. As should be apparent from the above description and the various illustrations, the automatic closing of the pollution control valve 104 is independent of the flow and pressure of the wellbore fluid.

In some examples, the rotation of the weight 152 to the position shown in FIG. 9 indicates that the pollution control valve 104 has been closed. For example, an operator can visually inspect whether the weight 152 has been rotated to the position shown in FIG. 9 and thereby confirm that that the sealing sleeve 130 has moved to the closed position that seals the internal bore 126. The pollution control valve 104 can be reset to the open position by rotating the weight 152, and thereby the arm 150, to the position shown in FIG. 8, for example by grasping the weight 152, by deactivating or reversing a hydraulic, linear, electric, pneumatic, and/or other actuator, etc.), and/or the like.

The following clauses describe further aspects of the disclosure:

Clause Set A:

Al . A pollution control valve for a stuffing box of a pump system, said pollution control valve comprising:

a body having an internal bore configured to receive a drive shaft of the pump system; a sealing sleeve held within the internal bore of the body, the sealing sleeve comprising a passage extending through the sealing sleeve, the sealing sleeve being moveable between an open position and a closed position that prevents fluid from flowing through the internal bore, the passage being aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve; and an actuator configured to bias the sealing sleeve toward the closed position.

A2. The pollution control valve of clause Al, wherein the sealing sleeve is held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore.

A3. The pollution control valve of clause Al, wherein the bias of the actuator is configured to move the sealing sleeve from the open position to the closed position upon the drive shaft exiting the internal bore.

A4. The pollution control valve of clause Al, wherein the sealing sleeve is configured to rotate between the open position and the closed position. A5. The pollution control valve of clause Al, wherein the sealing sleeve comprises a bearing held within the passage of the sealing sleeve.

A6. The pollution control valve of clause Al, wherein the sealing sleeve comprises a bearing held within the passage of the sealing sleeve, the bearing comprising balls held by a retaining ring, the balls being configured to rotate in response to at least one of rotational or reciprocal motion of the drive shaft within the internal bore.

A7. The pollution control valve of clause Al , wherein the actuator comprises a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

A8. The pollution control valve of clause Al, wherein the sealing sleeve comprises a curved exterior shape.

A9. The pollution control valve of clause Al, wherein the sealing sleeve comprises a spherical segment shape.

Clause Set B:

Bl. A stuffing box assembly for a pump system, said stuffing box assembly comprising:

a stuffing box configured to be connected to a well head, the stuffing box being configured to receive a drive shaft of the pump system through the stuffing box; and

a pollution control valve comprising:

a body having an internal bore, the body being connected to the stuffing box such that the drive shaft is configured to extend through the internal bore;

a sealing sleeve held within the internal bore of the body, the sealing sleeve comprising a passage extending through the sealing sleeve, the sealing sleeve being moveable between an open position and a closed position that prevents fluid from flowing through the internal bore, the passage being aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve; and

an actuator configured to bias the sealing sleeve toward the closed position. B2. The stuffing box assembly of clause Bl , wherein the sealing sleeve of the pollution control valve is held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore.

B3. The stuffing box assembly of clause Bl , wherein the bias of the actuator of the pollution control valve is configured to move the sealing sleeve from the open position to the closed position upon the drive shaft exiting the internal bore.

B4. The stuffing box assembly of clause B 1 , wherein the sealing sleeve of the pollution control valve is configured to rotate between the open position and the closed position.

B5. The stuffing box assembly of clause Bl , wherein the sealing sleeve of the pollution control valve comprises a bearing held within the passage of the sealing sleeve.

B6. The stuffing box assembly of clause Bl , wherein the sealing sleeve of the pollution control valve comprises a bearing held within the passage of the sealing sleeve, the bearing comprising balls held by a retaining ring, the balls being configured to rotate in response to at least one of rotational or reciprocal motion of the drive shaft within the internal bore.

B7. The stuffing box assembly of clause Bl , wherein the actuator of the pollution control valve comprises a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

B8. The stuffing box assembly of clause Bl , wherein the sealing sleeve of the pollution control valve comprises a curved exterior shape.

B9. The stuffing box assembly of clause Bl , wherein the sealing sleeve of the pollution control valve comprises a spherical segment shape.

Clause Set C: C 1. A pollution control valve for a stuffing box of a pump system, said pollution control valve comprising:

a body having an internal bore configured to receive a drive shaft of the pump system; a sealing sleeve held within the internal bore of the body, the sealing sleeve comprising a passage extending through the sealing sleeve, the sealing sleeve being moveable between an open position and a closed position that prevents fluid from flowing through the internal bore, the passage being aligned with the internal bore in the open position such that the drive shaft is configured to be received through the passage in the open position of the sealing sleeve, the sealing sleeve being held in the open position against the bias of the actuator by the presence of the drive shaft within the internal bore, wherein the sealing sleeve comprises a spherical segment shape; and

an actuator configured to bias the sealing sleeve toward the closed position.

C2. The pollution control valve of clause CI , wherein the actuator comprises a weight configured to bias the sealing sleeve to the closed position under the force of gravity.

It is to be understood that the above description is intended to be illustrative, and not restrictive. For example, the above-described embodiments (and/or aspects thereof) may be used in combination with each other. Furthermore, invention(s) have been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the invention(s). Further, each independent feature or component of any given assembly may constitute an additional embodiment. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the disclosure without departing from its scope. Dimensions, types of materials, orientations of the various components, and the number and positions of the various components described herein are intended to define parameters of certain embodiments, and are by no means limiting and are merely exemplary embodiments. Many other embodiments and modifications within the spirit and scope of the claims will be apparent to those of skill in the art upon reviewing the above description. The scope of the disclosure should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

In the foregoing description of certain embodiments, specific terminology has been resorted to for the sake of clarity. However, the disclosure is not intended to be limited to the specific terms so selected, and it is to be understood that each specific term includes other technical equivalents which operate in a similar manner to accomplish a similar technical purpose. Terms such as "clockwise" and "counterclockwise", "left" and right", "front" and "rear", "above" and "below" and the like are used as words of convenience to provide reference points and are not to be construed as limiting terms.

When introducing elements of aspects of the disclosure or the examples thereof, 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. For example, in this specification, the word "comprising" is to be understood in its "open" sense, that is, in the sense of "including", and thus not limited to its "closed" sense, that is the sense of "consisting only of. A corresponding meaning is to be attributed to the corresponding words "comprise", "comprised", "comprises", "having", "has", "includes", and "including" where they appear. The term "exemplary" is intended to mean "an example of." The phrase "one or more of the following: A, B, and C" means "at least one of A and/or at least one of B and/or at least one of C." Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to impose numerical requirements on their objects. Further, the limitations of the following claims are not written in means-plus-function format and are not intended to be interpreted based on 35 U.S.C. § 112(f), unless and until such claim limitations expressly use the phrase "means for" followed by a statement of function void of further structure.

Although the terms "step" and/or "block" may be used herein to connote different elements of methods employed, the terms should not be interpreted as implying any particular order among or between various steps herein disclosed unless and except when the order of individual steps is explicitly described. The order of execution or performance of the operations in examples of the disclosure illustrated and described herein is not essential, unless otherwise specified. The operations may be performed in any order, unless otherwise specified, and examples of the disclosure may include additional or fewer operations than those disclosed herein. It is therefore contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the disclosure.

Having described aspects of the disclosure in detail, it will be apparent that modifications and variations are possible without departing from the scope of aspects of the disclosure as defined in the appended claims. As various changes could be made in the above constructions, products, and methods without departing from the scope of aspects of the disclosure, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.