NUT ANTI-ROTATION FLUID END ASSEMBLIES

Abstract

The present disclosure relates to reciprocating pumps, such as to fluid end assemblies of reciprocated pumps. In a first aspect, a fluid end assembly includes a body defining a bore and including at least one first thread. The assembly further includes a cover capable of being disposed within the bore, a nut including at least one second thread, and a retainer capable of being disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body. The at least one second thread can engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover. Other aspects and features are also claimed and described.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and benefit of U.S. Provisional Patent Application No. 63/649,548, entitled “NUT ANTI-ROTATION FLUID END ASSEMBLIES,” filed May 20, 2024, the contents of which are incorporated in their entirety for all purposes.

FIELD OF DISCLOSURE

The present disclosure relates generally to reciprocating pumps; and more particularly, but not by way of limitation, to fluid end assemblies.

BACKGROUND

Reciprocating pumps, also known as positive displacement pumps, are used in many applications and industries to convert mechanical energy into hydraulic energy. Reciprocating pumps generally include two sections: a power end and a fluid end. The power end is configured to move one or more plungers toward, and away from, the fluid end. The fluid end is where the pumping takes place-fluid is drawn in and forcibly pushed out at a high pressure by the plungers.

SUMMARY

The present disclosure provides a fluid end assembly for a reciprocating pump that addresses face cracks occurring around a preload-applying nut as a result of pressure pulse-induced vibrations. The fluid end assembly includes a nut in threaded engagement with a body of a fluid end of a reciprocating pump. The nut applies compressive preload to a cover and tensile preload to at least one thread of the body. The fluid end assembly further includes a retainer capable of restricting rotation of the nut relative to the body. Stated differently, the retainer restricts the nut from backing out from the at least one thread of the body such that the tensile preload is maintained between at least one thread of the nut and the at least one thread of the body, and the compressive preload is maintained on the cover. In this way, the fluid end assembly reduces the likelihood of face cracks occurring in the body around the nut.

In an example, the retainer includes an internal retaining ring that can be inserted into a groove of the body of the fluid end, subsequent to preload being applied to the cover, such that the internal retaining ring restricts rotation of the nut to maintain the preload. In another example, the retainer includes a plurality of tabs that can be inserted into the groove and coupled to the nut, subsequent to preload being applied to the cover, such that the plurality of tabs restrict rotation of the nut. In another example, the retainer includes a plurality of spring-loaded detents that may be coupled to the nut prior to preload being applied to the cover. The spring-loaded detents are biased into indents of the body of the fluid end to restrict rotation of the nut. While the different examples of the retainer are described herein in the context of a fluid end assembly, the retainer embodiments may be used in other systems.

In some embodiments, the cover of the fluid end assembly includes a conical portion and the nut includes a split end resembling a split lock nut. The split end 290 is disposed around the conical portion such that conical portion forces threaded tabs of the split end into at least one thread of the body of the fluid end assembly, thereby discouraging rotating of the nut. While the cover including the conical portion and the nut including the split end are described herein in the context of a fluid end assembly, these embodiments of the cover and nut may be used in other systems.

In some embodiments, the fluid end assembly may include a component for determining a value of the preload applied to the cover. For example, the fluid end assembly may include a piston (e.g., a hydraulic piston) used for determining a value for the preload applied. In another example, the fluid end assembly may include a custom load cell capable of measuring a value of the compressive load between the nut and the cover.

Any implementation of any of the apparatuses, systems, and methods can consist of or consist essentially of—rather than comprise/include/have—any of the described steps, elements, and/or features. Thus, in any of the claims, the term “consisting of” or “consisting essentially of” can be substituted for any of the open-ended linking verbs recited above, in order to change the scope of a given claim from what it would otherwise be using the open-ended linking verb. Additionally, it will be understood that the term “wherein” may be used interchangeably with “where.”

Further, a device or system that is configured in a certain way is configured in at least that way, but it can also be configured in other ways than those specifically described. Aspects of one example may be applied to other examples, even though not described or illustrated, unless expressly prohibited by this disclosure or the nature of a particular example. Some details associated with the aspects described above and others are described below.

Some details associated with the aspects are described above, and others are described below. Other implementations, advantages, and features of the present disclosure will become apparent after review of the entire application, including the following sections: Brief Description of the Drawings, Detailed Description, and the Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

These drawings illustrate by way of example and not limitation. For the sake of brevity and clarity, every feature of a given structure is not always labeled in every figure in which that structure appears. Identical reference numbers do not necessarily indicate the same structure. Rather, the same reference number may be used to indicate a similar feature or a feature with similar functionality, as may non-identical reference numbers.

FIG. 1 is a cross-section view of a reciprocating pump according to some aspects of this disclosure.

FIG. 2 is a box diagram of a fluid end assembly according to some aspects of this disclosure.

FIG. 3A is a perspective view of a cover according to some aspects of this disclosure.

FIG. 3B is a perspective view of a nut according to some aspects of this disclosure.

FIG. 3C is a perspective view of a retaining ring according to some aspects of this disclosure.

FIG. 3D is a perspective cross-section view of a fluid end assembly according to some aspects of this disclosure.

FIG. 4A is a perspective view of a nut according to some aspects of this disclosure.

FIG. 4B is a perspective view of a retainer coupled to the nut of FIG. 4A according to some aspects of this disclosure.

FIG. 4C is a perspective cross-section view of a fluid end assembly including the retainer and nut of FIGS. 4A and 4B according to some aspects of this disclosure.

FIG. 5A is a perspective view of a nut including spring-loaded detents as a retainer according to some aspects of this disclosure.

FIG. 5B is a perspective view of a spring-loaded detent according to some aspects of this disclosure.

FIG. 5C is a perspective view of a bore including indentations according to some aspects of this disclosure.

FIG. 5D is a perspective cross-section view of a fluid end assembly including the nut of FIG. 5A according to some aspects of this disclosure.

FIG. 6A is a perspective view of a cover including a conical portion according to some aspects of this disclosure.

FIG. 6B is a perspective view of a nut including a split end according to some aspects of this disclosure.

FIG. 6C is a cross-section view of a fluid end assembly including the cover and nut of FIGS. 6A and 6B, respectively, according to some aspects of this disclosure.

FIG. 7A is a perspective view of a piston according to some aspects of this disclosure.

FIG. 7B is a perspective view of a hydraulic fitting according to some aspects of this disclosure.

FIG. 7C is a cross-section view of a fluid end assembly including the piston according to some aspects of this disclosure.

FIG. 8A is a perspective view of a load cell according to some aspects of this disclosure.

FIG. 8B is a cross-section view of a fluid end assembly including the load cell according to some aspects of this disclosure.

FIG. 9 is a flow chart of a method of assembling a fluid end assembly according to some aspects of this disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE ASPECTS

Referring to FIG. 1, a reciprocating pump 100 is shown. Reciprocating pump 100 has two sections: a power end 110 and a fluid end 150. Power end 110 is configured to move one or more plungers toward, and away from, fluid end 150. Fluid end 150 is where the pumping takes place-fluid is drawn in and forcibly pushed out at a high pressure by the plungers.

Power end 110 includes a plurality of plunger assemblies 120, a plurality of crankshaft assemblies 130, and a power end frame assembly having a plurality of bearing plates 140. Because FIG. 1 is a cross-section view of reciprocating pump 100, only one plunger assembly 120, crankshaft assembly 130, and bearing plate 140 is shown. Each plunger assembly 120 includes a plunger 122, a crosshead 124, and a connecting rod 126. Plunger 122 is coupled to crosshead 124 via a ponyrod 128. Connecting rod 126 couples crosshead 124 to crankshaft assembly 130 via rod cap 129.

Each crankshaft assembly 130 has at least a portion partially positioned within an opening 142 on bearing plate 140 and includes a crankshaft 132 and a crankshaft bearing 134 around crankshaft 132. Crankshaft bearing 134 is supported by opening 142 and couples crankshaft 132 to bearing plate 140 while allowing crankshaft 132 to rotate within opening 142. Adjacent bearing plates 140 of the power end frame assembly form receptacles 146 that accommodate crosshead 124 and configure crosshead 124 to displace linearly as crankshaft 132 rotates.

Fluid end 150 includes a fluid end assembly 151 having a plurality of bodies 152, each body 152 having a chamber 160, an inlet port 170, a discharge port 180, and an access port 190. Because FIG. 1 is a cross-section view of reciprocating pump 100, only one body 152 is shown. Chamber 160 is configured to receive a plunger portion of plunger 122 and allow the plunger portion to reciprocate within chamber 160. Inlet port 170 includes an inlet valve 174 and is configured to receive a fluid and direct the fluid to enter chamber 160. Discharge port 180 includes a discharge valve 184 and is configured to receive the fluid from chamber 160 and direct the fluid to exit body 152. Access port 190 includes a cover 194 that is removable to allow access to components of body 152 and/or fluid end assembly 151. Access port 190 further includes a nut 196 that may be threaded into the body 152 of the access port 190.

Reciprocating pump 100 increases pressure of the fluid in chamber 160 by reciprocating plunger 122 longitudinally within chamber 160. As a result, low-pressure fluid enters chamber 160 via inlet port 170 and high-pressure fluid exits chamber 160 and is discharged via discharge port 180. During operation of the reciprocating pump 100, the nut 196 applies compressive force to the cover 194 that counteracts the force of the pressure in chamber 160 that acts upon the cover 194.

Fluid ends of conventional reciprocating pumps can suffer from face cracks occurring around nut 196 as a result of pressure pulse-induced vibrations. For instance, the pressure pulse-induced vibrations may cause nut 196 to back out (e.g., rotate counterclockwise) from the at least one thread of body 152 of access port 190, which reduces the tensile preload between the at least one thread of nut 196 and the at least one thread of body 152. The loss of tensile preload accelerates fatigue of the at least one thread of body 152, thereby eventually resulting in face cracks in body 152 around nut 196.

Fluid end assembly 151 of reciprocating pump 100 addresses this problem by including a retainer 198 configured to restrict rotation of nut 196 relative to body 152. Stated differently, retainer 198 restricts nut 196 from backing out from the at least one thread of body 152 such that the tensile preload is maintained between the at least one thread of nut 196 and the at least one thread of body 152. In this way, fluid end assembly 151 reduces the likelihood of face cracks occurring in body 152 around nut 196. The retainer 198 is depicted as a retaining ring in FIG. 1, though may have other suitable configurations as will be described below.

FIG. 2 is a box diagram of fluid end assembly 151. As described, fluid end assembly 151 includes body 152. Body 152 includes a bore 202 that defines access port 190. Body 152 further includes at least one thread 204 (e.g., at least one interior thread). In various examples, the at least one thread 204 may be a buttress thread, though can be other suitable thread forms in other examples. Fluid end assembly 151 also includes cover 194 and nut 196 that are each configured to be disposed within bore 202. Nut 196 includes at least one thread 206 (e.g., at least one exterior thread) capable of engaging with the at least one thread 204. In various examples, the at least one thread 206 may be a buttress thread, though can be other suitable thread forms in other examples. Fluid end assembly 151 further includes retainer 198 that is also configured to be disposed within bore 202. In some embodiments, retainer 198 may be omitted.

FIGS. 3A to 3D illustrate a portion of a first embodiment of fluid end assembly 151 including a first embodiment of retainer 198. In this first embodiment of retainer 198, retainer 198 includes a retaining ring 198A (e.g., an internal retaining ring). Cover 194, nut 196, and retaining ring 198A are each shown disposed within bore 202 of body 152 in FIG. 3D. The at least one thread 206 of nut 196 is engaged with the at least one thread 204 of body 152 such that nut 196 compresses cover 194 against body 152. In this way, nut 196 applies a compressive preload on the cover 194. For instance, with the aid of a tool, nut 196 may be tightened relative to body 152 by rotating nut 196 clockwise to apply the compressive preload. Tightening nut 196 also applies tensile preload on the at least one thread 204 of body 152 via the at least one thread 206 of nut 196.

Retaining ring 198A maintains the compressive preload and the tensile preload by restricting nut 196 from backing out of the at least one thread 204. For instance, body 152 includes a groove 220 in which retaining ring 198A may be disposed. Retaining ring 198A disposed in the groove 220 thereby restricts nut 196 from rotating counterclockwise by blocking nut 196 from advancing towards the mouth of bore 202. Retaining ring 198A may be inserted into groove 220 subsequent to the compressive and tensile preloads being applied. For instance, retaining ring 198A may be deformed so that retaining ring 198A can be inserted into bore 202, and then released such that retaining ring 198A snaps back to a pre-deformed state into groove 220.

In some instances, the end of nut 196 does not contact retaining ring 198A after the preload is applied. In such instances, nut 196 may marginally rotate counterclockwise and back out from bore 202, thereby marginally reducing the applied preload, until nut 196 contacts retaining ring 198A and is thereafter restricted from rotating.

FIGS. 4A to 4C illustrate a portion of the first embodiment of fluid end assembly 151 including a second embodiment of retainer 198. Only the differences between the first and second embodiments of retainer 198 will be described. In this second embodiment, retainer 198 includes a plurality of tabs 198B coupled to nut 196. For example, the plurality of tabs 198B may include tabs 240A, 240B, and 240C. Tabs 240A, 240B, and 240C are coupled to nut 196 via a plurality of bolts 242 inserted into openings 230 of nut 196. In other embodiments, tabs 240A, 240B, and 240C may be coupled to nut 196 in other suitable manners. Similar to the first embodiment, tabs 240A, 240B, and 240C may be inserted into groove 220 of body 152 such that nut 196 is blocked from advancing towards the mouth of bore 202. Tabs 240A, 240B, and 240C may be inserted into groove 220, and coupled to nut 196, subsequent to the compressive and tensile preloads being applied.

FIGS. 5A to 5D illustrate a portion of the first embodiment of fluid end assembly 151 including a third embodiment of retainer 198. Only the differences between the third embodiment and the first and second embodiments of retainer 198 will be described. In this third embodiment, retainer 198 includes a plurality of spring-loaded detents 198C. For example, the plurality of spring-loaded detents 198C may include spring-loaded detents 260A, 260B, 260C, and 260D. Each of spring-loaded detents 260A, 260B, 260C, and 260D are coupled to nut 196. For example, as shown in FIG. 5B, spring-loaded detent 260A (as a representative example of the plurality of spring-loaded detents 198C) includes a body having at least one thread 262, and a detent 264 biased by a spring (not shown) to be partially exterior to the body. The plurality of spring-loaded detents 198C may each be coupled to nut 196 via respective at least one threads 262 in this example. In other examples, each of the plurality of spring-loaded detents 198C may be coupled to the nut 196 in another suitable manner. In other embodiments, each of the plurality of spring-loaded detents 198C may be integral with the nut 196.

Body 152 is shown in FIG. 5C to include a plurality of indents 270 disposed near the mouth of bore 202. While nut 196 is advanced into bore 202, each of the respective detents 264 is forced by body 152 to retract against the biasing force of the respective springs until each of the respective detents 264 is aligned with a respective indent of the plurality of indents 270. At that point, the respective springs force the plurality of spring-loaded detents 198C into the plurality of indents 270. When each of the plurality of spring-loaded detents 198C are disposed in each of the plurality of indents 270, the nut 196 is restricted from rotating relative to body 152. The compressive and tensile preloads are thereby maintained.

In some instances, the plurality of spring-loaded detents 198C are not perfectly aligned with the plurality of indents 270 after the preload is applied. In such instances, nut 196 may marginally rotate counterclockwise and back out from bore 202, thereby marginally reducing the applied preload, until the respective springs force the plurality of spring-loaded detents 198 C into the plurality of indents 270.

In some embodiments, the retaining ring 198A and the groove 220, or the plurality of tabs 198B and the groove 220, may be included with fluid end assembly 151 in addition to the plurality of spring-loaded detents 198C.

FIGS. 6A to 6C illustrate a portion of a second embodiment of fluid end assembly 151. In this second embodiment, cover 194 includes a conical portion 280. Additionally, nut 196 resembles a split lock nut. For example, nut 196 includes a split end 290 that includes a plurality of tabs 292A, 292B such that a gap 294 exists between adjacent tabs 292A, 292B.

As shown in FIG. 6C, split end 290 is configured to be disposed around conical portion 280 such that conical portion 280 forces the plurality of tabs 292A, 292B in the direction of arrows 302, away from a central axis 304 extending through nut 196. For example, an exterior diameter (e.g., distance between outer exterior surfaces) of conical portion 280 is larger than an interior diameter (e.g., distance between opposing interior surfaces of tabs 292A, 292B) of split end 290 such that when split end 290 is torqued onto conical portion 280, conical portion 280 forces tabs 292A, 292B into the at least one thread 204 of body 152. As a result, there is greater force engagement between the at least one thread 204 of body 152 and the at least one thread 206 of nut 196, which increases the resistance against nut 196 rotating counterclockwise relative to body 152, and thereby improves the consistency of the preload applied to cover 194.

In some embodiments, retaining ring 198A and the groove 220, or the plurality of tabs 198B and the groove 220, or the plurality of spring-loaded detents 198C and the plurality of indentations 270 may be included with the second embodiment of fluid end assembly 151. In some embodiments, a combination of retaining ring 198A and the plurality of spring-loaded detents 198C, or a combination of the plurality of tabs 198B and the plurality of spring-loaded detents 198C, may be included with the second embodiment.

The above-described embodiments of fluid end assembly 151 and retainer 198 allow for improving the consistency of preloaded applied to cover 194 during an instance of operation of reciprocating pump 100. In some embodiments, fluid end assembly 151 may include a component for determining a value of the applied preload. For example, preload is typically applied manually by an operator, such as by using a hammer and a torque wrench. The various operators that apply the preload can have different strengths, thereby leading to inconsistently applied preloads. It may be beneficial in certain applications, however, to apply a consistent preload across different instances of operation of the reciprocating pump 100. Additionally or alternatively, it may be beneficial in certain applications to ensure that a predetermined value of preload is applied to cover 194.

FIGS. 7A to 7C illustrate a portion of a third embodiment of fluid end assembly 151 that includes a piston 250 (e.g., a hydraulic piston) used for determining a value for the preload applied. As shown in FIG. 7C, piston 250 may be disposed between cover 194 and nut 196. Oil is disposed in a gap 254 between piston 250 and nut 196. Fluid end assembly 151 further includes a hydraulic fitting 252 disposed within a channel of the nut 196.

In this third embodiment of fluid end assembly 151, when assembling fluid end assembly 151, nut 196 is advanced all the way into bore 202, but torque need not be applied to build preload. Rather, with nut 196 advanced into bore 202, piston 250 is pressurized in order to apply the compressive preload and the tensile preload. Because a diameter of piston 250 and a pressure of the oil in gap 254 are known, the compressive and tensile preloads applied can be determined as a product of the oil pressure multiplied by a surface area of a face 256 of piston 250.

It should be appreciated that the third embodiment of fluid end assembly 151 is not limited to including retaining ring 198A as retainer 198, as shown in FIG. 7B. For example, in other embodiments, retaining ring 198A may be replaced by the plurality of tabs 198B, or by the plurality of spring-loaded detents 198C. In other embodiments, a combination of retaining ring 198A and the plurality of spring-loaded detents 198C may be utilized. In other embodiments, a combination of the plurality of tabs 198B and the plurality of spring-loaded detents 198C may be utilized.

FIGS. 8A and 8B illustrate a portion of a fourth embodiment of fluid end assembly 151 that includes a load cell 310 used for determining a value for the preload applied. As shown in FIG. 8B, load cell 310 may be the disposed between cover 194 and nut 196. Load cell 310 is a custom load cell configured to measure a value of the compressive load between nut 196 and cover 194. In an example, when load cell 310 is under load and is deformed, the electrical properties (e.g., resistance) of load cell 310 are changed. The electrical properties can be measured and serve as a proxy for measuring the preload applied.

It should be appreciated that the fourth embodiment of fluid end assembly 151 is not limited to including the plurality of spring-loaded detents 198C as retainer 198, as shown in FIG. 8B. For example, in other embodiments, the plurality of spring-loaded detents 198C may be replaced by retaining ring 198A or the plurality of tabs 198B. In other embodiments, a combination of retaining ring 198A and the plurality of spring-loaded detents 198C may be utilized. In other embodiments, a combination of the plurality of tabs 198B and the plurality of spring-loaded detents 198C may be utilized. In other embodiments, retainer 198 may be omitted.

Referring to FIG. 9, a method 400 of assembling a fluid end assembly (e.g., fluid end assembly 151) of a fluid end (e.g., fluid end 150) of a reciprocating pump (e.g., reciprocating pump 100) is provided. Method 400 includes, at block 402, providing a cover (e.g., cover 194) in a bore (e.g., bore 202) of a body (e.g., body 152) of the fluid end 151. At block 404, a nut (e.g., nut 196) is advanced into the bore 202 via engagement between at least one first thread (e.g., at least one first thread 204) of the body 152 and at least one second thread (e.g., at least one second thread 206) of the nut 196 so that the nut 196 contacts the cover 194. In some aspects, advancing the nut 196 into the bore 202 includes advancing a split end (e.g., split end 290) of the nut 196 onto the cover 194. In such aspects, the cover 194 may include a conical portion 280 onto which the split end 290 is advanced.

In some aspects, a piston (e.g., piston 250) is provided in the bore 202 subsequent to providing the cover 194 in the bore 202 and prior to advancing the nut 196 into the bore 202. In some aspects, a load cell (e.g., load cell 310) is provided in the bore 202 subsequent to providing the cover 194 in the bore 202 and prior to advancing the nut 196 into the bore 202.

At block 406, a preload is applied to the cover 194. In some aspects, the preload may be applied by torquing the nut 196. For example, the nut 196 may be manually torqued, such as by using a torque wrench (e.g., a hydraulic torque wrench). In other aspects, the preload may be applied by pressurizing the piston 250. In some aspects, a predetermined amount of preload is applied to the cover 194. For example, the piston 250 may be pressurized an amount corresponding to the predetermined amount preload so that the predetermined amount preload is applied. In another example, the amount of preload applied can be determined via load cell 310, and thus the nut 196 may be torqued until the predetermined amount of preload is achieved.

At block 408, a retainer (e.g., retainer 198) is applied such that the retainer 198 restricts rotation of the nut 196 relative to the body 152. The retainer 198 is applied subsequent to the preload being applied to the cover 194. For example, the retainer 198 may be a retaining ring 198A that is applied by being inserted into a groove (e.g., groove 220) of body 152. When in the groove 220, the retaining ring 198A is disposed relative to the nut 196 such that the retaining ring 198A restricts rotation of the nut 196 relative to the body 152. In another example, retainer 198 may be a plurality of tabs (e.g., plurality of tabs 198B) that are applied by being inserted into the groove 220 and coupled to the nut 196. When in the groove 220, the plurality of tabs 198B are disposed relative to the nut 196 such that the plurality of tabs 198B restrict rotation of the nut 196 relative to the body 152. In another example, the retainer 198 may be a plurality of spring-loaded detents (e.g., plurality of spring-loaded detents 198C) that are applied by being inserted into a plurality of indents (e.g., plurality of indents 270) of body 152. When in the plurality of indents 270, the plurality of spring-loaded detents 198C are disposed relative to the nut 196 such that the plurality of spring-loaded detents 198C restrict rotation of the nut 196 relative to the body 152.

The above specification and examples describe the structure and use of illustrative implementations. Although certain examples have been described above with some particularity, or with reference to one or more individual examples, those skilled in the art could make numerous alterations to the disclosed implementations without departing from the scope of this invention. So the various illustrative implementations of the methods and systems are not intended to be limited to the particular forms disclosed. Rather, they include all modifications and alternatives falling within the scope of the claims, and examples other than the one shown may include some or all of the features of the depicted example. For example, elements may be omitted or combined as a unitary structure, and/or connections may be substituted. Further, where appropriate, aspects of any of the examples described above may be combined with aspects of any of the other examples described to form more examples having comparable or different properties and/or functions and addressing the same or different problems. Similarly, it will be understood that the benefits and advantages described above may relate to one embodiment or may relate to several implementations.

In a first aspect, a fluid end assembly includes a body defining a bore and including at least one first thread, a cover configured to be disposed within the bore, a nut including at least one second thread, and a retainer configured to be disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body. The at least one second thread is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover.

In a second aspect, in combination with the first aspect, the at least one first thread and the at least one second thread each include buttress threading.

In a third aspect, in combination with one or more of the first through the second aspects, the nut is disposed between the cover and the retainer.

In a fourth aspect, in combination with one or more of the first through the third aspect, the body defines a groove configured to receive the retainer.

In a fifth aspect, in combination with one or more of the first through the fourth aspect, the retainer includes a retaining ring.

In a sixth aspect, in combination with one or more of the first through the fourth aspect, the retainer includes a plurality of tabs coupled to the nut.

In a seventh aspect, in combination with one or more of the first through the sixth aspect, the retainer includes a plurality of spring-loaded detents.

In an eighth aspect, in combination with the seventh aspect, the body defines a plurality of indents configured to receive the plurality of spring-loaded detents.

In a ninth aspect, in combination with one or more of the first through the eighth aspect, the fluid end assembly further includes a hydraulic piston disposed between the cover and the nut.

In a tenth aspect, in combination with one or more of the first through the ninth aspect, the fluid end assembly further includes a load cell disposed between the cover and the nut and configured to determine a compressive load between the cover and the nut.

In an eleventh aspect, in combination with one or more of the first through the tenth aspect, the cover includes a conical portion, the nut includes a split end that is split into a plurality of tabs, and the split end is configured to be disposed around the conical portion such that the conical portion forces the plurality of tabs away from a central axis extending through the nut.

In a twelfth aspect, a fluid end assembly includes a body defining a bore and including at least one first thread, a cover configured to be disposed within the bore, and a nut including at least one second thread. The at least one second thread is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover. The cover includes a conical portion. The nut includes a split end that is split into a plurality of tabs. The split end is configured to be disposed around the conical portion such that the conical portion forces the plurality of tabs away from a central axis extending through the nut.

In a thirteenth aspect, in combination with the twelfth aspect, the fluid end assembly further includes a retainer disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body.

In a fourteenth aspect, in combination with the thirteenth aspect, the body defines a groove configured to receive the retainer.

In a fifteenth aspect, in combination with the thirteenth aspect, the nut is disposed between the cover and the retainer.

In a sixteenth aspect, in combination with the thirteenth aspect, the retainer includes a retaining ring.

In a seventeenth aspect, in combination with the thirteenth aspect, the retainer includes a plurality of tabs coupled to the nut.

In an eighteenth aspect, in combination with the thirteenth aspect, the retainer includes a plurality of spring-loaded detents.

In a fifteenth aspect, in combination with the eighteenth aspect, the body defines a plurality of indents configured to receive the plurality of spring-loaded detents.

In a sixteenth aspect, in combination with the twelfth aspect, the first and second threading each include buttress threading.

In a seventeenth aspect, in combination with one or more of the second through the eleventh aspects, a pump includes a power end and a fluid end. The fluid end includes: a body defining a bore and including at least one first thread, a cover configured to be disposed within the bore, a nut including at least one second thread, and a retainer configured to be disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body. The at least one second thread is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover.

As used herein, various terminology is for the purpose of describing particular implementations only and is not intended to be limiting of implementations. For example, as used herein, an ordinal term (e.g., “first,” “second,” “third,” etc.) used to modify an element, such as a structure, a component, an operation, etc., does not by itself indicate any priority or order of the element with respect to another element, but rather merely distinguishes the element from another element having a same name (but for use of the ordinal term). The term “coupled” is defined as connected, although not necessarily directly, and not necessarily mechanically; two items that are “coupled” may be unitary with each other. The terms “a” and “an” are defined as one or more unless this disclosure explicitly requires otherwise. The term “substantially” is defined as largely but not necessarily wholly what is specified—and includes what is specified; e.g., substantially 90 degrees includes 90 degrees and substantially parallel includes parallel—as understood by a person of ordinary skill in the art. In any disclosed embodiment, the term “substantially” may be substituted with “within [a percentage] of” what is specified, where the percentage includes 0.1, 1, 5, and 10 percent; and the term “approximately” may be substituted with “within 10 percent of” what is specified. The phrase “and/or” means “and” or “or.” To illustrate, A, B, and/or C includes: A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C. In other words, “and/or” operates as an inclusive or. The phrase “A, B, C, or a combination thereof” includes A alone, B alone, C alone, a combination of A and B, a combination of A and C, a combination of B and C, or a combination of A, B, and C. In other words, “or” is used inclusively unless otherwise is expressly specified.

The terms “comprise” and any form thereof such as “comprises” and “comprising,” “have” and any form thereof such as “has” and “having,” and “include” and any form thereof such as “includes” and “including” are open-ended linking verbs. As a result, an apparatus that “comprises,” “has,” or “includes” one or more elements possesses those one or more elements, but is not limited to possessing only those elements. Likewise, a method that “comprises,” “has,” or “includes” one or more steps possesses those one or more steps, but is not limited to possessing only those one or more steps.

The claims are not intended to include, and should not be interpreted to include, means-plus- or step-plus-function limitations, unless such a limitation is explicitly recited in each claim using the phrase(s) “means for” or “step for,” respectively.

Claims

1. A fluid end assembly comprising:

a body defining a bore and including at least one first thread;

a cover configured to be disposed within the bore;

a nut including at least one second thread that is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover; and

a retainer configured to be disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body.

2. The fluid end assembly of claim 1, wherein the at least one first thread and the at least one second thread each include buttress threading.

3. The fluid end assembly of claim 1, wherein the nut is disposed between the cover and the retainer.

4. The fluid end assembly of claim 1, wherein the body defines a groove configured to receive the retainer.

5. The fluid end assembly of claim 1, wherein the retainer includes a retaining ring.

6. The fluid end assembly of claim 1, wherein the retainer includes a plurality of tabs coupled to the nut.

7. The fluid end assembly of claim 1, wherein the retainer includes a plurality of spring-loaded detents.

8. The fluid end assembly of claim 7, wherein the body defines a plurality of indents configured to receive the plurality of spring-loaded detents.

9. The fluid end assembly of claim 1, further comprising a hydraulic piston disposed between the cover and the nut.

10. The fluid end assembly of claim 1, further comprising a load cell disposed between the cover and the nut and configured to determine a compressive load between the cover and the nut.

11. The fluid end assembly of claim 1, wherein:

the cover includes a conical portion,

the nut includes a split end that is split into a plurality of tabs, and

the split end is configured to be disposed around the conical portion such that the conical portion forces the plurality of tabs away from a central axis extending through the nut.

12. A fluid end assembly comprising:

a body defining a bore and including at least one first thread;

a cover configured to be disposed within the bore, wherein the cover includes a conical portion; and

a nut including at least one second thread and a split end that is split into a plurality of tabs, wherein the at least one second thread is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover,

wherein the split end is configured to be disposed around the conical portion such that the conical portion forces the plurality of tabs away from a central axis extending through the nut.

13. The fluid end assembly of claim 12, further comprising a retainer disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body.

14. The fluid end assembly of claim 13, wherein the body defines a groove configured to receive the retainer.

15. The fluid end assembly of claim 13, wherein the nut is disposed between the cover and the retainer.

16. The fluid end assembly of claim 13, wherein the retainer includes a retaining ring.

17. The fluid end assembly of claim 13, wherein the retainer includes a plurality of tabs coupled to the nut.

18. The fluid end assembly of claim 13, wherein the retainer includes a plurality of spring-loaded detents.

19. A pump comprising:

a power end; and

a fluid end, wherein the fluid end includes: a body defining a bore and including at least one first thread; a cover configured to be disposed within the bore; a nut including at least one second thread that is configured to engage with the at least one first thread such that, when the at least one second thread is engaged with the at least one first thread, the nut applies compressive force to the cover; and a retainer configured to be disposed relative to the nut such that the retainer restricts the nut from rotating relative to the body.

20. The pump of claim 19, wherein the at least one first thread and the at least one second thread each include buttress threading.