Patent ID: 12258850

DETAILED DESCRIPTION

Fluid End Assembly

Turning now toFIGS.3-85, a high pressure pump50is shown inFIG.3. The pump50comprises a fluid end assembly52joined to a power end assembly54. The power end assembly54is described in more detail in U.S. patent application Ser. No. 17/884,691, authored by Keith et al., and filed on Aug. 10, 2022, the entire contents of which are incorporated herein by reference (hereinafter “the '691 application”). In alternative embodiments, the fluid end assembly52may be attached to other power end designs known in the art. The fluid end assembly52and its various embodiments are described herein.

Fluid End Section

Turning toFIGS.4-10, the fluid end assembly52comprises a plurality of fluid end sections56positioned in a side-by-side relationship, as shown inFIGS.6-8. Each fluid end section56is attached to the power end assembly54using a plurality of stay rods58, each surrounded by a sleeve94, as shown inFIGS.4and5. Preferably, the fluid end assembly52comprises five fluid end sections56positioned adjacent one another. In alternative embodiments, the fluid end assembly52may comprise more or less than five fluid end sections56. In operation, a single fluid end section56may be removed and replaced without removing the other fluid end sections56from the fluid end assembly52.

Housing of Fluid End Section

With reference toFIGS.11-17, each fluid end section56comprises a horizontally positioned housing60having a longitudinal axis62extending therethrough, as shown inFIGS.14and15. The housing60has opposed front and rear surfaces64and66joined by an outer intermediate surface68. A horizontal bore70is formed within the housing60and interconnects the front and rear surfaces64and66, as shown inFIGS.16and17. The horizontal bore70is sized to receive various components configured to route fluid throughout the housing60, as shown inFIGS.11-13. The various components will be described in more detail later herein.

The housing60is of multi-piece construction. The housing60comprises a first section72joined to a second section74by a plurality of first fasteners78, as shown inFIG.17. Positioned intermediate the first and second sections72and74is a front spacer sleeve76. The first fasteners78also extend through the front spacer sleeve76. By making the housing60out of multiple pieces rather than a single, integral piece, either one of the sections72and74may be removed and replaced with a new section72and74, without replacing the other sections. For example, if a portion of the second section74begins to erode or crack, the second section74can be replaced without having to replace the first section72. Likewise, the front spacer sleeve76may be removed and replaced with a new spacer sleeve76, without replacing the sections72or74. In contrast, if the housing60were one single piece, the entire housing would need to be replaced, resulting in much more costly repair to the fluid end assembly52.

First Section of Housing

Turning toFIGS.18-21, the first section72is positioned at the front end of the housing60and includes the front surface64. The first section72is configured to be attached to a plurality of the stay rods58, as shown inFIGS.20and21. Thus, each fluid end section56is attached to the power end assembly54via the first section72of the housing60.

Continuing withFIGS.18and19, each first section72comprises the front surface64joined to a rear surface80. The surfaces64and80are interconnected by a portion of the outer intermediate surface68and a portion of the horizontal bore70. The outer intermediate surface68of the first section72has the shape of a rectangular prism with a plurality of notches82formed within the front surface64. A notch82is formed within each corner of the first section72such that the front surface64has a cross-sectional shape of a cross sign having radiused corners. The notches82are configured to receive a first end84of each stay rod58, as shown inFIG.22.

A plurality of passages86are formed in the first section72. Each passage86interconnects the rear surface80and a medial surface88of the first section72. The medial surface88is defined by the plurality of notches82. Each passage86comprises a counterbore87that opens on the rear surface80and is configured to receive a corresponding one of the stay rods58, as shown inFIG.23. When installed within the first section72, the first end84of each stay rod58projects from the medial surface88and into the corresponding notch82, as shown inFIG.22.

A threaded nut90is installed on the first end84of each stay rod58within each notch82. The nut90is a three-piece nut, also known as a torque nut, which facilitates the application of high torque required to properly fasten the fluid end section56to the power end assembly54. The nut90is described in more detail in the '691 application. In alternative embodiments, a traditional 12-point flange nut similar to the nut208, shown inFIG.28, may be installed on the first end84of each stay rod58instead of the nut90.

Disposed around a portion of each stay rod58is a sleeve94that extends between the rear surface80of the first section72and the power end assembly54, as shown inFIG.3. A dowel sleeve93is inserted into each counterbore87formed in each passage86, as shown inFIGS.22and23. When installed therein, a portion of the dowel sleeve93projects from the rear surface80of the first section72. A counterbore95is formed within the hollow interior of the sleeve94for receiving the projecting end of the dowel sleeve93, as shown inFIG.23. The dowel sleeve93aligns the sleeve94and the passage86concentrically. Such alignment maintains a planar engagement between the rear surface80of the first section72and the sleeve94. When the nut90is torqued against the medial surface88of the first section72, the sleeve94abuts the rear surface80of the first section72, rigidly securing the first section72to the stay rod58.

Turning back toFIGS.17and19, a plurality of threaded openings96are formed in the rear surface80of the first section72. The openings96surround an opening of the horizontal bore70, as shown inFIG.19. Each opening96is configured to receive a corresponding one of the first fasteners78used to secure the sections72and74and the front spacer sleeve76together, as shown inFIG.17.

Turning back toFIG.16, a pair of upper and lower discharge bores102and104are formed within the first section72and interconnect the intermediate surface68and the horizontal bore70. The upper and lower discharge bores102and104shown inFIG.16are collinear. In alternative embodiments, the bores102and104may be offset from one another and not collinear. Each bore102and104is configured to interface with a discharge conduit105, as shown inFIG.3. Each discharge conduit105is in fluid communication with an upper or lower discharge manifold109or117, as shown inFIG.3.

The discharge conduits105may be connected to the corresponding bore102or104by a discharge fitting107, as also shown inFIG.3. Each discharge fitting107may be installed within a counterbore106formed in the corresponding bore102and104, as shown for example inFIG.16. A groove110may be formed in the side walls of the counterbore106for receiving a seal112, as shown inFIG.16. The seal112is configured to engage an outer surface of the discharge fitting107to prevent fluid from leaking between the components, as shown for example the embodiment shown inFIG.96.

With reference toFIGS.14and15, a plurality of threaded openings114are formed in the intermediate surface68and surrounding the openings of the upper and lower discharge bores102and104. The threaded openings114are configured to receive a plurality of threaded fasteners115configured to secure the discharge fitting107to the first section72, as shown for example in the embodiment shown inFIG.94.

Turning back toFIG.16, a pair of upper and lower suction bores133and134are also formed within the first section72of the housing60, each suction bore133and134interconnecting the intermediate surface68and the horizontal bore70. The upper and lower suction bores133and134shown inFIG.9are collinear. In alternative embodiments, the bores133and134may be offset from one another and not collinear.

The suction bores133and134are each configured to interface with a suction conduit136, as shown inFIG.3. Each suction conduit136is in fluid communication with a an upper or lower suction manifold111or119, as shown inFIG.3. The suction conduits136may be attached to the intermediate surface68of housing60using a plurality of threaded openings139, as shown inFIGS.14and15. In alternative embodiments, the suction conduits may thread into a portion of the suction bores, as shown for example in the embodiment shown inFIG.96.

Continuing withFIGS.16and17, the walls surrounding the horizontal bore70within the first section72and positioned between the front surface64and the upper and lower discharge bores102and104are sized to receive a front retainer118and a discharge plug120, as shown inFIGS.11-13. As will be described in more detail later herein, the discharge plug120seals fluid from leaking from the front surface64of the housing60, and the front retainer118secures the discharge plug120within the first section72of the housing60.

Internal threads122are formed in the walls of the first section72for mating with external threads124formed on an outer surface of the front retainer118, as shown inFIGS.82and83. In contrast, an outer surface of the discharge plug120faces the smooth walls of the first section72. A small amount of clearance may exist between the plug120and the walls of the first section72, as shown inFIGS.11-13.

Continuing withFIGS.16and17, a groove125is formed in the walls surrounding the discharge plug120. The groove125is sized to receive an annular seal126configured to engage an outer surface of the discharge plug120, as shown inFIGS.11-13. The seal126prevents fluid from leaking around the discharge plug120during operation. A locating cutout128is further formed in the walls that are configured to receive a locating dowel pin130, as shown inFIG.11. As will be described later herein, the locating dowel pin130is used to properly align the discharge plug120within the housing60.

Staying withFIGS.11-13, the walls surrounding the horizontal bore70within the first section72of the housing60are configured to receive a majority of a fluid routing plug132as well as a discharge valve138, both of which will be described in more detail later herein. The fluid routing plug132is configured to route fluid throughout the housing60. Portions of the fluid routing plug132may engage or closely face the wall of the horizontal bore70to the front and rear of each upper and lower suction bore133and134.

More specifically, a first portion142of the wall of the horizontal bore70positioned between the upper and lower discharge bores102and104and the upper and lower suction bores133and134may be characterized as a sealing surface142. As will be described herein, the sealing surface142is configured to engage a seal144carried by the fluid routing plug132. A second portion146of the wall of the horizontal bore70is positioned between the upper and lower suction bores133and134and the rear surface80of the first section72. The second portion146is configured to closely face a portion of the fluid routing plug132. A small amount of clearance may exist between the second portion146of the walls and an outer surface of the fluid routing plug132.

Second Section of Housing

Turning toFIGS.24and25, the second section74of the housing60includes the rear surface66of the housing60. The second section74comprises a front surface148joined to the rear surface66by a portion of the outer intermediate surface68and a portion of the horizontal bore70. The outer intermediate surface68comprises a front mounting flange150positioned adjacent the front surface148and a rear mounting flange152positioned adjacent the rear surface66.

The front and rear mounting flanges150and152break up the intermediate surface68of the second section74such that a front projecting portion154of the intermediate surface68exists between the front surface148and the front mounting flange150, and a rear projecting portion156of the intermediate surface68exists between the rear surface66and the rear mounting flange152. Finally, a medial portion158of the intermediate surface68exists between the front and rear mounting flanges150and152. The front and rear mounting flanges150and152each have a greater outer diameter than that of the front, rear, and medial portions154,156, and158of the intermediate surface68, as shown inFIGS.16and17. The front mounting flange150further has a greater outer diameter than the rear mounting flange152.

Continuing withFIGS.24and25, a plurality of first passages160are formed within the front mounting flange150. The first passages160surround the horizontal bore70. Each first passage160is configured to receive one of the first fasteners78, as shown inFIG.17. When the first and second sections72and74are joined together, a space exists around the front portion154and between the rear surface80of the first section72and the front mounting flange150. As will be described herein, the space is sized to receive the front spacer sleeve76. A plurality of clearance notches162are also formed in the outer intermediate surface68of the front mounting flange150. Each clearance notch162is sized to partially surround a corresponding sleeve94and stay rod58when the fluid end52is assembled, as shown inFIG.5.

Continuing withFIGS.24and25, a plurality of second passages164are formed within the rear mounting flange152. As will be described herein, the second passages164are configured to receive a plurality of second fasteners166in a one-to-one relationship, as shown inFIG.13. When a stuffing box167, described later herein, is attached to the second section74, a space exists around the rear portion156of the second section74and between the rear surface66and the rear mounting flange152. As will be described herein, the space is sized to receive a rear spacer sleeve168, as shown inFIGS.11-13.

A plurality of dowel openings170are also formed with the rear mounting flange152, each opening facing the rear surface66of the housing60and is configured to receive a portion of a first dowel pin172, as shown inFIG.17. Each first dowel pin172is configured to extend between the rear mounting flange152and the rear spacer sleeve168. A plurality of threaded openings174are further formed in the rear mounting flange152, each opening facing the rear surface66of the housing60. The threaded openings174are preferably diametrically opposed to one another and are each configured to receive one of a plurality of third fasteners176, as shown inFIG.12. The third fasteners176are configured to secure the rear spacer sleeve168to the second section74of the housing60.

Turning back toFIGS.16and17, a first counterbore or first annular groove178is formed in the wall of the horizontal bore70of the second section74. The first counterbore178opens at the front surface148of the second section74and is characterized by a base180joined to a side wall182. The side wall182tapers slightly between the base180and the front surface148of the second section74. As will be described herein, the first counterbore178is sized to receive an annular and hardened insert184configured to engage a portion of the fluid routing plug132, as shown inFIGS.11-13. The second section74further comprises a first seal groove186formed within a center of the side wall182of the first counterbore178. The first seal groove186is sized to receive an annular seal188configured to engage the annular insert184, as shown inFIGS.11-13.

A second counterbore or second annular groove189is also formed in the wall of the horizontal bore70of the second section74, as shown inFIGS.16and17. The second counterbore189opens at the rear surface66of the housing60and is characterized by a side wall190joined to a base191. The side wall190tapers slightly between the base191and the rear surface66of the second section74. As will be described herein, the second counterbore189is sized to receive an annular wear ring192and an annular seal193, as shown inFIGS.11-13. The second section74further comprises a second seal groove194formed within a center of the side wall190of the second counterbore189. The second seal groove194is sized to receive an annular seal195configured to engage the wear ring192, as shown inFIGS.11-13. The second counterbore189further opens into a stuffing box counterbore196positioned farther within the horizontal bore70. The stuffing box counterbore196is sized to receive a portion of the stuffing box167, as shown inFIGS.11-13.

Staying withFIGS.11-13, the wall of the horizontal bore70of the second section74adjacent the front surface148is configured to receive a portion of the fluid routing plug132, a suction valve guide282, and a suction valve280. The wall of the horizontal bore70of the second section74adjacent the rear surface66is configured to receive a portion of the stuffing box167and a portion of a reciprocating plunger240.

Front Spacer Sleeve

With reference toFIGS.26and27, the front spacer sleeve76comprises opposed front and rear surfaces200and201joined by a central opening202and an outer intermediate surface203. A plurality of passages204are formed in the front spacer sleeve76surrounding the central opening202. The plurality of passages204are each sized to receive one of the first fasteners78and are positioned to correspond with the passages96formed in the rear surface80of the first section72, as shown inFIG.17.

A plurality of clearance notches205are formed in the outer intermediate surface203of the front spacer sleeve76. Each clearance notch205is sized to partially surround a corresponding sleeve94and stay rod58when the fluid end52is assembled, as shown inFIG.5. The clearance notches205align with the clearance notches162formed in the front mounting flange150of the second section74of the housing60when the fluid end52is assembled, as shown inFIG.10.

The central opening202of the front spacer sleeve76is sized to receive the front portion154of the second section74of the housing60such that the front spacer sleeve76surrounds the front portion154of the second section74, as shown inFIGS.16and17. When the front portion154is installed within the central opening202, an outer diameter of the front spacer sleeve76is equal or substantially equal to and aligned with an outer diameter of the front mounting flange150.

During operation, the central opening202of the front spacer sleeve76is sized so that it never applies any meaningful compressive force to the front portion154of the second section74of the housing60. Specifically, the front spacer sleeve76does not constrain the expansion of the front portion154of the second section74when the annular insert184is pressed into the first counterbore178. This results in more uniform deflection of the insert184during installation. The stress resulting from such deflection is therefore also more uniform. As a result, stress concentration areas within the insert184are eliminated or significantly reduced, thereby increasing the life of the insert and extending the time between maintenance intervals for the fluid end section56.

The front spacer sleeve76is also sized so that the front surface200of the spacer sleeve76shares the compressive load with the front surface148of the second section74of the housing60. Sharing of the compressive load between the two components reduces the stress on the front surface148of the second section74. The rear surface201of the front spacer sleeve76provides a reactionary surface for the front surface of the front mounting flange150. Providing such surface reduces the bending deflection of the front mounting flange150and consequently the bending stress on the front mounting flange150. The benefits provided by the front spacer sleeve76increase the life of the corresponding components, thereby extending the time between maintenance intervals for the fluid end section56.

Assembly of Housing

With reference toFIG.12, prior to assembling the housing60, the seal188is installed within the first seal groove186formed in the second section74and the insert184is press-fit or interference fit into the first counterbore178. The seal188shown in the figures is an O-ring seal, but other types of seals known in the art may also be used. The insert184will be described in more detail later herein.

Following installation of the seal188and the insert184, the housing60is assembled by threading a first threaded end206of each of the first fasteners78into a corresponding one of the threaded openings96formed in the first section72, as shown inFIGS.12and17. Once installed therein, the first fasteners78project from the rear surface80of the first section72. The front spacer sleeve76is then slid onto the first fasteners78using the corresponding passages204, as shown inFIGS.28and29. The front spacer sleeve76is aligned such that the clearance notches205correspond with the stay rod passages86formed within the first section72.

After the front spacer sleeve76is in place, the second section74of the housing60is slid onto the first fasteners78using the corresponding passages160formed in the front mounting flange150, as shown inFIGS.28and29. At the same time, the front portion154of the second section74is inserted into the central opening202of the front spacer sleeve76until the front surface148of the second section74abuts the rear surface80of the first section72, as shown inFIG.17.

When the second section74is brought together with the first section72, a second threaded end207of each first fastener78projects from the front mounting flange150and extends over the medial portion158of the intermediate surface68. At the same time, the front spacer sleeve76is sandwiched between the rear surface80of the first section72and the front mounting flange150such that the front and rear surfaces200and201of the front spacer sleeve76abut the corresponding surfaces. The second section74of the housing60is aligned on the first fasteners78such that the clearance notches162formed in the front mounting flange150align with the clearance notches205formed in the front spacer sleeve76, as shown inFIG.10.

The assembled sections72and74are secured together by installing a threaded nut208onto the second end207of each first fastener78, as shown inFIGS.14and15. The nut208shown in the figures is a flanged nut having a 12-point drive section. The nut208is turned on the second end207of the fastener78to the desired specification or until it tightly engages the front mounting flange150. When installed thereon, each nut208overlaps the medial portion158and is positioned intermediate the front and rear mounting flanges150and152of the second section74of the housing60.

Twelve first fasteners78and corresponding threaded openings96, passages160and204, and nuts208are shown in the figures. In alternative embodiments, more or less than twelve first fasteners78and corresponding openings96, passages160and204, and nuts208may be used to assemble the housing60. When the housing60is assembled, the first fasteners78are each positioned along an axis that is parallel to the longitudinal axis62of the housing60, as shown inFIG.17.

The first fastener78shown in the figures is a threaded stud. In alternative embodiments, other types of fasteners known in the art may be used instead of a threaded stud. For example, screws or bolts may be used to secure the sections together. In further alternative embodiments, the nut208may comprise the three-piece nut90, shown inFIG.20, or other types of threaded nuts known in the art.

To remove a section72or74or remove the front spacer sleeve76, the nut208is unthreaded from the second end207of each first fastener78. The sections72and74and the rear spacer sleeve76may then be pulled apart, as needed. If the first section72is being replaced, the first fasteners78are also unthreaded from the threaded openings96. The components installed within the housing60may also be removed, as needed, prior to disassembling the housing60.

Components Attached to Rear Surface of Housing

Turning back toFIGS.9-13, in addition to the housing60, the fluid end section56comprises a plurality of components attached to the rear surface66of the housing60. Such components are configured to receive the plunger240. The various components include the stuffing box167and the rear spacer sleeve168, previously mentioned. The components further comprise a rear retainer209, plunger packing210, and a packing nut211.

Rear Spacer Sleeve

With reference toFIGS.30and31, the rear spacer sleeve168comprises opposed front and rear surfaces212and213joined by a central opening214and an outer intermediate surface215. A plurality of first passages216are formed in the rear spacer sleeve168surrounding the central opening214. The plurality of first passages216are each sized to receive one of the second fasteners166, as shown inFIG.13. A plurality of counterbored passages217are also formed within the rear spacer sleeve168, as shown inFIG.12. The counterbored passages217are positioned to align with the threaded openings174formed in the rear mounting flange152and are configured to receive a corresponding third fastener176. A counterbore218of each counterbored passage217opens on the rear surface213of the rear spacer sleeve168. Finally, a plurality of dowel passages219are formed within the rear spacer sleeve168. Each dowel passage219is positioned to align with a corresponding dowel opening170formed in the rear mounting flange152, as shown inFIG.17.

The central opening214of the rear spacer sleeve168is sized to receive the rear portion156of the second section74of the housing60such that the rear spacer sleeve168surrounds the rear portion156of the second section74, as shown inFIG.17. When the rear portion156is installed within the central opening214, an outer diameter of the rear spacer sleeve168is equal to or substantially equal to and aligned with an outer diameter of the rear mounting flange152.

Like the front spacer sleeve76, the central opening214of the rear spacer sleeve168is sized so that it never applies any meaningful compressive force to the rear portion156of the second section74of the housing60. Specifically, the rear spacer sleeve168does not constrain the expansion of the rear portion156of the second section74when the wear ring192is pressed into the second counterbore189. This results in more uniform deflection of the wear ring192during installation. The stress resulting from such deflection is therefore also more uniform. As a result, stress concentration areas within the wear ring192are eliminated or significantly reduced, thereby increasing the life of the wear ring192and extending the time between maintenance intervals for the fluid end section56.

Like the front spacer sleeve76, the rear spacer sleeve168is also sized so that the rear surface213of the spacer sleeve168shares the compressive load with the rear surface66of the housing60. Sharing of the compressive load between the two components reduces the stress on the rear surface66of the housing60. The front surface212of the rear spacer sleeve168provides a reactionary surface for the rear surface of the rear mounting flange152. Providing such surface reduces the bending deflection of the rear mounting flange152and consequently the bending stress on the rear mounting flange152. The benefits provided by the rear spacer sleeve168increase the life of the corresponding components, thereby extending the time between maintenance intervals for the fluid end section56.

Stuffing Box

Turning toFIGS.32and33, the stuffing box167is configured to house the plunger packing210described below. The stuffing box167comprises opposed front and rear surfaces220and221joined by an outer intermediate surface222and a central passage223formed therein. The stuffing box167further comprises a front portion224joined to a rear portion225. The front portion224has a smaller outer diameter than the rear portion225such that a medial surface226is formed between the front and rear surfaces220and221. The front portion224further has a smaller length than that of the rear portion225and may be characterized as a front projecting portion224.

The front portion224includes the front surface220of stuffing box167, and the rear portion225includes the rear surface221of the stuffing box167. An internal shoulder227is formed in the wall of the central passage223within the rear portion225. The plunger packing210abuts the internal shoulder227when installed within the stuffing box167, as shown inFIGS.11-13.

A plurality of passages228are formed within the rear portion225of the stuffing box167and interconnect the medial surface226and the rear surface221. The passages228are configured to align with the plurality of first passages216formed in the rear spacer sleeve168and are configured to receive one of the plurality of second fasteners166, as shown inFIG.13. A plurality of dowel openings229are formed in the rear surface221of the stuffing box167for receiving second alignment dowels230, as shown inFIGS.84and85. The second alignment dowels230assist in properly aligning the rear retainer209on the stuffing box167during assembly.

Turning back toFIGS.11-13, the stuffing box167is installed within the second section74of the housing60such that the front portion224is disposed within the stuffing box counterbore196and a portion of the medial surface226abuts the rear surface66of the housing60. When installed therein, a space exists between the rear mounting flange152and the medial surface226of the stuffing box167. As described below, such space is filled by the rear spacer sleeve168. When the front portion224of the stuffing box167is installed within the second section74of the housing60, the outer intermediate surface222of the front portion224engages the seal193. The seal193prevents fluid from leaking between the housing60and the stuffing box167. The seal193shown in the figures is a high pressure seal and is significantly larger than the seal195engaging the opposite side of the wear ring192.

During operation, the seal193wears against the outer intermediate surface222of the front portion224. Should the front portion224begin to erode, the stuffing box167may be removed and replaced with a new stuffing box167. Likewise, the seal193wears against the wear ring192during operation. The wear ring192is preferably made of a harder and more wear resistant material than the housing60, such as tungsten carbide. Should the wear ring192begin to erode, the wear ring192can be removed and replaced with a new wear ring192. Likewise, the seal193can also be removed and replaced with a new seal193, if needed. Locating the seal193between replaceable parts protects the housing60over time. Fluid is prevented from leaking around the wear ring192by the seal195installed within the second seal groove194.

Rear Retainer

Turning toFIGS.34and35, the rear retainer209comprises opposed front and rear surfaces231and232joined by an outer intermediate surface233and a central passage234formed therein. A plurality of passages235are formed in the rear retainer209and surround the central passage234. The passages235interconnect the front and rear surfaces231and232of the rear retainer209and are configured to align with the passages228formed in the rear portion225of the stuffing box167, as shown inFIG.13. A plurality of dowel openings236are formed in the front surface231of the rear retainer209for receiving a portion of the second alignment dowels230, as shown inFIGS.84and85.

An internal shoulder237is formed in the wall of the central passage234of the rear retainer209. Internal threads238are formed in the wall of the central passage234and are positioned between the internal shoulder237and the rear surface232. The internal threads238are configured to receive the packing nut211, as shown inFIGS.11-13. Between the internal shoulder237and the front surface231, the wall of the central passage234is smooth and includes one or more lubrication ports239. The lubrication port239interconnects the central passage234and the outer intermediate surface233of the rear retainer209, as shown inFIG.11. During operation, lubricant is supplied to the fluid end section56through the lubrication port239.

Plunger Packing and Packing Nut

Continuing withFIGS.11-13, fluid is prevented from leaking around the plunger240during operation by a plunger packing210. The plunger packing210is installed within the stuffing box167and comprises a plurality of packing seals241sandwiched between first and second metal rings242and243. The first metal ring242abuts the internal shoulder227formed within the stuffing box167and the second metal ring243extends into the central passage223formed in the rear retainer209. The second metal ring243is known in the art as a “lantern ring”. One or more passages244may be formed in the second metal ring243and fluidly connect with the one or more lubrication ports239formed in the rear retainer209, as shown inFIG.11. During operation, oil used to lubricate the plunger240and plunger packing210is supplied through the lubrication port239and second metal ring243.

With reference toFIGS.36and37, the plunger packing210is retained within the stuffing box167and the rear retainer209using the packing nut211. The packing nut211comprises opposed front and rear surfaces245and246joined by an outer intermediate surface247and a central passage248formed therein. External threads249are formed in a portion of the outer intermediate surface247for engaging the internal threads238formed in the rear retainer209, as shown inFIGS.11-13. When the packing nut211is installed within the rear retainer209, the front surface245of the packing nut211engages the lantern ring243and compresses the plunger packing210, as shown inFIGS.11-13. When compressed, the packing seals241of the plunger packing210tightly seal against an outer surface of the plunger240.

During operation, the packing nut211may be tightened, as needed, to ensure adequate compression of the packing seals241against the plunger240. At least a portion of the packing nut211projects from the rear surface232of the rear retainer209to provide clearance to turn the packing nut211, as needed. One or more mounting holes250formed in the packing nut211adjacent its rear surface246are configured to engage tools used to turn the packing nut211. The central passage248formed in the packing nut211is sized to closely receive the plunger240. A groove251may be formed in the wall of the central passage248for receiving a seal252, as shown inFIGS.11-13. The seal252shown inFIGS.11-13is an O-ring. The seal252prevents fluid from leaking around the plunger240during operation.

Blind Nuts and Reaction Washers

Turning toFIGS.38-43, a blind nut253and a reaction washer254are installed in a first threaded end255of each second fastener166. The blind nut253is a flanged nut and comprises a flanged section256joined to a drive section257, as shown inFIGS.38-41. The flanged section256functions as a washer. The drive section257comprises a standard 12-point drive, sometimes called a double hex drive. A series of grooves258are formed in the outer surface of the drive section257and extend radially around the periphery of the outer surface of the drive section257. The grooves258are configured to receive a seal259, such as an O-ring seal. The seal259is configured to hold the reaction washer254on the blind nut253, as shown inFIG.45. The blind nut253further comprises a threaded blind bore260having a base261. An opening262may be formed in the base261for viewing the interior of the blind bore260.

With reference toFIGS.42and43, the reaction washer254comprises a pair of torque reaction arms264positioned on opposite sides of a central opening263. The reaction arms264are joined by a concave surface265sized to conform to the outer cylindrical surface of the medial portion158of the second section74of the housing60. The central opening263comprises a 12-point wall266that is congruent to the 12-point drive section257of the blind nut253.

The reaction washer254is shaped to slide over the drive section257of the blind nut253and is held on the drive section257by the seal259, as shown inFIGS.44and45. When installed thereon, at least one of the reaction arms264of the reaction washer254engages the medial portion158of the second section74. As will be described herein, during assembly of the fluid end section56, the reaction washers254provide a mechanism for resisting torque applied to the blind nuts253when other parts of the fluid end section56are assembled.

Assembly of Components on Rear Surface of Housing

Turning back toFIGS.11-13, the components at the rear surface66of the housing60are assembled by first inserting each of the second fasteners166through a corresponding one of the second passages164formed in the rear mounting flange152. The second fasteners166are pushed through the second passages164until a first threaded end255of each fastener166projects from the rear mounting flange152and is positioned over the medial portion158of the second section74of the housing60, as shown inFIGS.9and10. A blind nut253is then torqued onto each first threaded end255. The blind nut253is torqued until an end surface267of each first threaded end255abuts the base261of the threaded blind bore260, as shown inFIG.45.

After the blind nuts253are attached to the second fasteners166, a reaction washer254is installed around the drive section257of each blind nut253. Each reaction washer254is held on the blind nut253by sliding a seal259around each drive section257until it is positioned within the grooves258, as shown inFIGS.9,44, and45. The reaction washers254may be positioned on the blind nuts253immediately after attaching the blind nuts253to the second fasteners166or anytime prior to torquing a plurality of nuts268on the opposite second end269of each second fastener166.

Following the assembly of the second fasteners166and blind nuts253, a first dowel pin172is inserted into a corresponding one of the dowel openings170formed on the rear surface66of the second section74, as shown inFIG.17. The rear spacer sleeve168is then brought together with the second section74of the housing60such that the first dowel pins172are inserted into the dowel pin passages219, the second fasteners166are disposed within the passages216, and the threaded openings174are aligned with the counterbored passages217, as shown inFIGS.12and13. When in such position, the front surface212of the rear spacer sleeve168abuts the rear surface66of the housing60and the rear portion156of the second section74is installed within the central opening214of the rear spacer sleeve168.

The rear spacer sleeve168is secured to the rear surface66of the housing60by installing a third fastener176within a corresponding one of the aligned threaded openings174and counterbored passages217, as shown inFIG.12. The third fasteners176shown in the figures are screws. The third fasteners176are torqued within the threaded openings174until a head270of each fastener176abuts a base271of each counterbored passage217, thereby rigidly securing the rear spacer sleeve168to the housing60. When the rear spacer sleeve168is attached to the housing60, the rear surface213of the rear spacer sleeve168is positioned flush with the rear surface66of the housing60.

Continuing withFIGS.11-13, prior to attaching the stuffing box167to the housing60, the seal195is installed within the second seal groove194, and the wear ring192is press-fit or interference fit into the second counterbore189. The seal193is then installed within the wear ring192and the second counterbore189. The wear ring192is positioned intermediate the seals195and193such that the wear ring192surrounds the seal193. When the components are installed within the second counterbore189, a side surface of both the wear ring192and the annular seal193abut the base191of the second counterbore189. The opposite side surface of the wear ring192is flush with the rear surface66of the housing60.

To attach the stuffing box167to the housing60, the stuffing box167is brought together with the second section74by inserting the second fasteners166into a corresponding one of the passages228formed in the rear portion225of the stuffing box167. At the same time, the front portion224of the stuffing box167is installed within the stuffing box counterbore196such that the seal193surrounds and engages an outer surface of the front portion224. The stuffing box167is brought together with the housing60such that the rear surface66of the housing60and the rear surface213of the rear spacer sleeve168abut the medial surface226of the stuffing box167.

Once the stuffing box167is in place, the rear retainer209is attached to the stuffing box167. The rear retainer209is brought together with the stuffing box167by inserting the second fasteners166into the corresponding passages235formed in the rear retainer209. At the same time, the second dowel pins230are installed within the aligned dowel openings229formed in the rear surface221of the stuffing box167and the front surface231of the rear retainer209, as shown inFIGS.84and85. The rear retainer209is brought together with the stuffing box167until the front surface231of the rear retainer209abuts the rear surface221of the stuffing box167and a second threaded end269of each second fastener166projects from the rear surface231of the rear retainer209, as shown inFIGS.11-13.

Once the rear retainer209is in place, a reaction washer254and seal259are installed on each blind nut253and a washer272and threaded nut268are installed on the second threaded end269of each of the second fasteners166, as shown inFIGS.9and10. The threaded nut268may comprise a threaded through-bore and a 12-point outer drive section. The threaded nuts268are torqued to a desired specification or until the stuffing box167and the rear retainer209are rigidly secured to the housing60and the rear spacer sleeve168.

When turning the nuts268on the second end269of each second fastener166, the reaction washers254provide a mechanism for resisting the torque applied to the blind nuts253, allowing the nuts268to be tightened or loosened without the blind nuts253spinning freely. Specifically, rotation of the blind nut253is prevented by the engagement of one of the reaction arms264with the medial portion158of the housing60, as shown inFIG.44. After assembly, the reaction washers254may be removed from the blind nuts253. Alternatively, the reaction washers254may be left in place so as to prevent rotation of the blind nuts253during operation, thereby reducing the likelihood of the second fasteners166from coming loose.

After the rear spacer sleeve168, stuffing box167, and rear retainer209are attached to the housing60, the plunger packing210may be installed within the stuffing box167and the packing nut211may be installed within the rear retainer209, as shown inFIGS.11-13. The packing nut211is torqued within the rear retainer209as needed to compress the packing seals210.

Eight second fasteners166are shown in the figures. In alternative embodiments, more or less than eight second fasteners166may be used. The second fasteners166shown in the figures are each a threaded stud. In alternative embodiments, other types of fasteners known in the art may be used instead of a threaded stud. For example, screws or bolts may be used to secure the sections together. In further alternative embodiments, the nut268may comprise the three-piece nut90, shown inFIG.20, or other types of threaded nuts known in the art.

As shown inFIGS.9,10,12, and13, when the fluid end section56is assembled, the second ends207of the first fasteners78and the corresponding nuts208and the first ends255of the second fasteners166and the corresponding blind nuts253are in a spaced-relationship and face each other. Both ends207and255and corresponding nuts208and253are positioned between the front and rear mounting flanges150and152and both ends overlap the medial portion158of the second section74. When assembled, the second fasteners166extend along an axis that is parallel to the longitudinal axis62of the housing60, as shown inFIG.13.

Components Installed within the Housing

Turning toFIGS.46-85, the various internal components of the housing60will now be described in more detail. Fluid is routed throughout the housing60by the fluid routing plug132. The timing of movement throughout the fluid routing plug132is controlled by the suction valve280and the discharge valve138. Movement of the valves280and138is guided by the suction valve guide282and the discharge plug120.

Fluid Routing Plug

Turning toFIGS.46-59, the fluid routing plug132comprises a body330having a suction surface332and an opposed discharge surface334joined by an outer intermediate surface336. A central longitudinal axis338extends through the body330and the suction and discharge surfaces332and334. When the fluid routing plug132is installed within the housing60, the discharge surface334is positioned within the first section72of the housing60, and at least a portion of the suction surface332is positioned within the second section74of the housing60, as shown inFIGS.11-13.

The body330further comprises a plurality of suction fluid passages340. The suction passages340interconnect the intermediate surface336and the suction surface332of the body330, as shown inFIG.51. The connection is formed within a blind bore342formed within the suction surface332of the body330. The blind bore342may be referred to as an axially-blind bore342because it is blind along the longitudinal axis338of the body330. During operation, fluid entering the housing60through the suction bores133and134flows into the suction passages340of the fluid routing plug132and into the axially-blind bore342. From there, fluid flows towards the suction surface332of the body330and out of the fluid routing plug132. Three suction fluid passages340are shown in the figures. In alternative embodiments, more or less than three suction fluid passages340may be formed within the body330.

Continuing withFIGS.52and53, each suction passage340has a generally oval or tear drop cross-sectional shape. An opening344of each suction passage340on the intermediate surface336comprises a first side wall346joined to a second side wall348by first and second ends350and352. The first and second side walls346and348are straight lines of equal length S, and the first and second ends350and352are circular arcs, as shown inFIG.53.

The first end350of the opening344has a radius of R1with a center at C1, and the second end352has a radius of R2with a center at C2. The first end350is larger than the second end352such that R1>R2. The first and second side walls346and348are tangent to the first and second ends350and352and have an included angle, σ.

The opening344has a centerline354that connects the centers C1and C2of the first and second ends350and352. The centerline354has a length E and is parallel with the central longitudinal axis338. A cross-sectional shape of each suction passage340throughout the length of the body330corresponds with the shape of each opening344. Each suction passage340is sized and shaped to maximize fluid flow through the passage340and minimize fluid turbulence and stress to the body330of the fluid routing plug132.

With reference toFIGS.55and56, each suction fluid passage340extends between the axially-blind bore342and the suction surface332such that each suction passage340comprises a longitudinal axis356. The longitudinal axis356extends through the center C1of the first end350of the opening344and intersects the central longitudinal axis338, as shown inFIG.55.

The body330further comprises a plurality of discharge fluid passages360. The discharge passages360interconnect the suction surface332and the discharge surface334of the body330and do not intersect any of the suction passages340, as shown inFIGS.57and58. Rather, the discharge and suction passages360and340are in a spaced-relationship. In operation, fluid exiting the body330at the suction surface332is subsequently forced into the discharge passages360, towards the discharge surface334of the body330, and out of the fluid routing plug132. Three discharge fluid passages360are shown in the figures. In alternative embodiments, more or less than three discharge fluid passages360may be formed within the body330.

The suction surface332of the body330comprises an outer rim362joined to the axially-blind bore342by a tapered seating surface366, as shown inFIG.51. Likewise, the discharge surface334comprises an outer rim368joined to a central base370by a tapered seating surface372, as shown inFIG.51.

Each discharge passage360opens at a first opening374on the outer rim362of the suction surface332and opens at a second opening376on the central base370of the discharge surface334, as shown inFIGS.46and49. The second openings376surround a blind bore378formed in the central base370of the discharge surface334. The blind bore378is configured to engage a tool used to grip the fluid routing plug132, as needed. For example, the walls of the blind bore378may be threaded. The central base370may also be slightly recessed from the tapered seating surface372such that a small counterbore380is created, as shown inFIG.51. The counterbore380helps further reduce any turbulence of fluid exiting the second openings376.

With reference toFIGS.54-58, the discharge passages360extend at an angle between the suction surface332and the discharge surface334. Each discharge passage360further has an arced cross-sectional shape. The length of the arc may gradually increase between the suction and discharge surfaces332and334. In alternative embodiments, the discharge passages360may have different shapes and sizes.

Turning back toFIG.51, a first annular groove384is formed in the outer intermediate surface336of the body330for housing a first seal144, as shown inFIGS.11-13. The first groove384is positioned adjacent the discharge surface334and is characterized by two sides walls388joined by a base390. When the fluid routing plug132is installed within the housing60, the first seal144engages the sealing surface142of the first section72of the housing60, as shown inFIGS.11-13and59. Fluid is prevented from leaking around the discharge surface334of the fluid routing plug132by the first seal144.

With reference toFIGS.51and59, a second annular groove392is formed in the outer intermediate surface336of the body330for housing a second seal394. The second groove392is positioned adjacent the suction surface332and is characterized by a plurality of side walls396joined by a base398, as shown inFIG.60. Four side walls396are shown inFIG.60such that the groove392has a rounded shape. When the fluid routing plug132is installed within the housing60, the second seal394engages an outer surface of the hardened insert184, as shown inFIGS.59and60. During operation, the second seal394wears against the insert184. If the insert184begins to erode, the insert184may be removed and replaced with a new insert184.

The outer intermediate surface336of the body330further comprises an annular shoulder400formed in the body330. The shoulder400is positioned between the opening344of the suction passages340and the second groove392. When the fluid routing plug132is installed within the housing60, the shoulder400abuts a front surface416of the insert184, as shown inFIGS.11-13and59. Axial movement of the fluid routing plug132towards the rear surface66of the housing60is prevented by the engagement between the shoulder400and the insert184. During operation, the shoulder400may wear against the insert184. If either feature begins to wear, the fluid routing plug132and/or the insert184may be removed and replaced with a new fluid routing plug132and/or insert184.

The annular shoulder400further comprises a stress relief cutout275, as shown inFIG.60. The annular shoulder400does not contact the insert184in this area. The absence of contact reduces the stress on the annular shoulder400during operation, helping to extend the life of the fluid routing plug132.

The outer intermediate surface336of the body330further comprises a concave surface408, as shown inFIG.47. The outer intermediate surface336of the body330slowly tapers outward from the concave surface408to adjacent the annular shoulder400. When the fluid routing plug132is installed within the housing60, the concave surface408provides clearance between the outer intermediate surface336of the fluid routing plug132and an opening of the suction bores133and134. Such clearance gives way to an annular fluid channel412formed between the first section72and the fluid routing plug132, as shown inFIG.59. The shape of the outer intermediate surface336of the fluid routing plug132helps direct fluid flowing from the suction bores133and134into the openings344of the suction passages340while minimizing fluid turbulence.

Turning toFIG.60, the outer intermediate surface336of the body330further comprises a bevel414formed in the body330. The bevel414is positioned between the Outer Rim362of the Suction Surface332and the Second Groove392. The Bevel414provides clearance to help install the fluid routing plug132within the housing60and the insert210.

Hardened Insert and Wear Ring

With reference toFIGS.60-64, the insert184has an annular shape and comprises opposed front and rear surfaces416and418joined by inner and outer intermediate surfaces420and422. The outer intermediate surface420tapers between the front and rear surfaces416and418. Such taper conforms to the tapered shape of the first counterbore178, as shown inFIG.60. The corresponding tapers help lock the insert184in place within the first counterbore178.

The insert184further comprises a first bevel426formed in the inner intermediate surface420adjacent the front surface416, as shown inFIGS.63and64. The first bevel426provides clearance to assist in installing the fluid routing plug132within the insert184within the housing60, as shown inFIG.60. The insert184also comprises a second bevel424formed in the outer intermediate surface422adjacent the rear surface418. The second bevel424provides clearance to assist in installing the insert184within the first counterbore178, as shown inFIG.60. The insert184is made of a harder and more wear resistant material than the housing60. For example, if the housing60is made of stainless steel, the insert184may be made of tungsten carbide. The insert184may also be characterized as a wear ring184.

With reference toFIGS.65-69, the wear ring192has an annular shape and comprises opposed front and rear surfaces417and419joined by inner and outer intermediate surfaces421and423. The outer intermediate surface423tapers between the front and rear surfaces417and419. Such taper conforms to the tapered shape of the second counterbore189, as shown inFIG.69. The corresponding tapers help lock the wear ring192in place within the second counterbore189.

The wear ring192further comprises a first bevel427formed in the outer intermediate surface423adjacent the front surface417, as shown inFIG.65. The first bevel427provides clearance to assist in installing the wear ring192within the second counterbore189, as shown inFIG.69. The wear ring192is made of a harder and more wear resistant material than the housing60. For example, if the housing60is made of stainless steel, the wear ring192may be made of tungsten carbide.

Suction and Discharge Valves

With reference toFIGS.70-73, the flow of fluid throughout the housing60and the fluid routing plug132is regulated by the suction and discharge valves280and138. The suction valve280is configured to engage the suction surface332, and the discharge valve138is configured to engage the discharge surface334of the fluid routing plug132such that the surfaces332and334function as valve seats, as shown inFIGS.11-13. The valves280and138are similar in shape but may vary in size. As shown inFIGS.11-13, the discharge valve138is slightly larger than suction valve280.

Continuing withFIGS.70-73, the discharge valve138is shown in more detail. The suction valve280has the same features as the discharge valve138so only the discharge valve138is shown in more detail in the figures. The discharge valve138comprises a stem402joined to a body428. The body428comprises an outer rim430joined to a valve insert432by a tapered seating surface434. An annular cutout436formed within the seating surface434is configured to house a seal438, as shown inFIG.73.

During operation, the seating surface434and the seal438engage the seating surface372of the discharge surface334and block fluid from entering or exiting the discharge passages360, as shown inFIG.12. Likewise, the seating surface434and the seal438on the suction valve280engage the seating surface366of the suction surface332and block fluid from entering or exiting the suction passages340within the axially-blind bore342, as shown inFIG.12.

When the seating surfaces434and372are engaged, the valve insert432extends partially into the counterbore380formed in the discharge surface334, as shown inFIG.11. Fluid exiting the second openings376of the discharge passages360contacts the insert432, pushing the discharge valve138away from the discharge surface334before flowing around the seating surface434of the discharge valve138, as shown inFIGS.12and13. Such motion enlarges the area for fluid to flow between the seating surfaces372and434before fluid reaches the surfaces372and434, thereby reducing the velocity of fluid flow within such area. The lowered fluid velocity between the surfaces372and434causes any wear to the valve138or280to be concentrated at the insert432instead of the crucial sealing elements, thereby extending the life of the valve138or280.

Likewise, the insert432on the suction valve280extends partially into the opening of the axially-blind bore342, as shown inFIGS.12and13. Fluid within the axially-blind bore342contacts the insert432before flowing around the seating surface434and seal438of the suction valve280. Such motion enlarges the area for fluid to flow between the seating surfaces366and434before fluid reaches the surfaces366and434, thereby reducing the velocity of fluid flow within such area.

Continuing withFIGS.70-73, the stem402projects from a top surface440of the body428of the valve138or280. The outer rim430surrounds the stem402and is spaced from the stem402by an annular void442. A groove444is formed in the outer rim430for receiving a portion of a spring446, as shown inFIGS.11-13.

During operation, the valves138and280move axially along the longitudinal axis62of the housing60between open and closed positions. In the closed position, the seating surface434and the seal438of each of the valves138and280tightly engage the corresponding seating surface372or366of the fluid routing plug132and the valve insert432is disposed within the corresponding bore380or342. In the open position, the seating surface434and the seal438are spaced from the corresponding seating surface372or366of the fluid routing plug132and the valve insert432is spaced from the corresponding bore380or342.

Suction Valve Guide

With reference toFIGS.74-77, axial movement of the suction valve280is guided by the suction valve guide282. The suction valve guide282comprises a thin-walled skirt448joined to a body450by a plurality of support arms452. The skirt448comprises a tapered upper section454joined to a cylindrical lower section456. The plurality of arms452join the tapered upper section454to the body450. A plurality of flow ports458are formed between adjacent arms452such that fluid may pass through the suction valve guide282during operation.

Continuing withFIGS.74-77, the suction valve guide282is installed within the housing60such that the tapered upper section454engages a tapered surface455of the wall of the horizontal bore70, as shown inFIG.13. Such engagement prevents further axial movement of the suction valve guide282within the housing60. When the suction valve guide282is installed within the housing60, the skirt448covers the wall of the horizontal bore70positioned between the flow ports458and the fluid routing plug132. During operation, fluid wears against the skirt448, thereby protecting the housing60from wear and erosion. If the skirt448begins to erode, the suction valve guide282can be removed and replaced with a new guide282.

The body450of the suction valve guide282is tubular and is centered within the skirt448. A tubular insert460is installed within the body450, as shown inFIG.11. The insert460is configured to receive the stem402of the suction valve280. During operation, the stem402moves axially within the insert460and wears against the insert460. An annular cutout462formed in the stem402, shown inFIGS.72and73, provides space for any fluid or other material trapped between the stem402and the insert460. The insert460is made of a harder and more wear resistant material than the body450thereby extending the life of the suction valve guide282. For example, if the body450is made of stainless steel, the insert460may be made of tungsten carbide.

A spring446is positioned between the outer rim430of the suction valve280and the plurality of arms452such that the spring446surrounds at least a portion of the body450of the suction valve guide282, as shown inFIGS.11-13. During operation, the spring446biases the suction valve280in a closed position, as shown inFIGS.12and13. Fluid pushing against the valve insert432moves the suction valve280axially to compress the spring446and move the suction valve280to an open position, as shown inFIG.11.

Discharge Plug

With reference toFIGS.78-81, axial movement of the discharge valve138is guided by the discharge plug120. The discharge plug120comprises a pair of legs464joined to a body466. The body466comprises a front portion468joined to a rear portion470by a medial portion472. The medial portion472has a larger outer diameter than both the front and rear portions468and470. An outer surface of the medial portion472engages the seal126installed within the first section72of the housing60, as shown inFIGS.11-13. The pair of legs464are joined to the medial portion472and extend between the medial portion472and the discharge surface334of the fluid routing plug132. A dowel opening474is formed in the outer surface of the medial portion472for receiving the locating dowel pin130, as shown inFIG.11. The discharge plug120is installed within the first section72of the housing60such that the locating dowel pin130is installed within the dowel opening474formed in the medial portion472and the locating cutout128formed in the first section72of the housing60, as shown inFIG.11. Such installation aligns the discharge plug120within the housing60so that the pair of legs464do not block the openings of the upper and lower discharge bores102and104.

The locating cutout128may be large enough to provide sufficient clearance for installation of the locating dowel pin130within the locating cutout128. The locating cutout128is sized to allow maximum clearance for assembly, but still maintain an acceptable rotational position of the discharge plug120. For example, the cutout128may be a maximum of 15 degrees wide along the circumference of the horizontal bore70.

Continuing withFIG.81, an axially-blind bore476extends within the body466and opens on the rear portion470of the body466. The bore476is sized to receive a tubular insert478, as shown inFIGS.11-13. The tubular insert478is similar to the tubular insert460installed within the suction valve guide282. The tubular insert478is configured to receive the stem402of the discharge valve138, as shown inFIGS.11-13.

During operation, the stem402moves axially within the tubular insert478. A plurality of passages480are formed in the body466and interconnect the bore476and an outer surface of the medial portion472. During operation, any fluid or other material trapped within the bore476exits the discharge plug120through the passages480. A spring446is positioned between the medial portion472of the plug120and the outer rim430of the discharge valve138, as shown inFIGS.11-13. The spring446biases the discharge valve138in the closed position, as shown inFIG.11. Fluid pushing against the valve insert432moves the discharge valve138axially to compress the spring446and move the discharge valve138to an open position, as shown inFIG.13.

The front portion468of the body466is sized to be disposed within a counterbore482formed within the front retainer118. When disposed therein, a rear surface484of the front retainer118abuts an outer surface of the medial portion472of the discharge plug120, as shown inFIGS.11-13. Such engagement holds the discharge plug120in place between the front retainer118and the fluid routing plug132. A blind bore486is formed in an outer surface of the front portion468of the plug120. The blind bore486is configured to engage a tool used to help install or remove the plug120from the housing60. For example, the bore486may have threaded walls.

Front Retainer

With reference toFIGS.82and83, the front retainer118comprises opposed front and rear surfaces488and484joined by an outer surface having external threads124and a horizontal bore490formed therein. The horizontal bore490comprises a hex portion492that opens in the counterbore482, as shown inFIGS.11-13. The hex portion492is configured to mate with a tool used to thread the front retainer118into the housing60until it abuts the discharge plug120, as shown inFIGS.11-13. An annular void494is formed within the front surface488of the front retainer118. The annular void494decreases the weight of the front retainer118, making it easier to thread into the housing60.

Suction and Discharge Manifolds

With reference toFIG.3, the discharge fitting107is configured to mate within one or more discharge conduits105included in an upper or lower discharge manifold109or117. The upper and lower discharge manifolds109and117are supported on a rack498, as shown inFIG.3. The fluid end assembly52is disposed within the interior open area of the rack498. The rack498supports the upper and lower discharge manifolds109or117in a spaced position from the discharge bores102and104. As a result, each discharge conduit105has an angled or bent shape. In operation, fluid discharges from the housing60through upper and lower discharge bores102and104and is carried to the corresponding upper or lower discharge manifolds109and117by the discharge fittings107and discharge conduits105.

Continuing withFIG.3, the suction conduits136are configured to mate with an upper or lower suction manifold111or119. The upper and lower suction manifolds111and119are supported on the rack498adjacent the discharge manifolds109or117. The suction conduits136may be flexible so that they may bend, as needed, to properly mate with the corresponding suction manifold111or119. In operation, fluid is drawn into the housing60from the suction manifolds111and119via the suction conduits136and the upper and lower suction bores133and134. In alternative embodiments, other known embodiments of suction and discharge conduits and/or corresponding fittings and manifolds may be used in place of those shown inFIG.3.

Assembly of Fluid End Section

With reference toFIGS.11-13,84, and85, prior to assembling the housing60, the seals188and195are installed in the corresponding groove186and194. Likewise, the hardened insert184is pressed into the first counterbore178and the wear ring192is pressed into the second counterbore189. The seal193is then installed within the wear ring192and the second counterbore189.

Following installation of the above components, the housing60may be assembled as described above. Thereafter, the rear spacer sleeve168, stuffing box167, rear retainer209, plunger packing210, and packing nut211may be attached to the rear surface66of the housing60. The plunger240is also inserted into the horizontal bore70through the packing nut211. The inner components of the housing60are inserted within the housing60through the front surface64of the first section72. The inner components may be installed prior to attaching the components to the rear surface66of the housing60, if desired. Following assembly of each fluid end section56, each section56is attached to the power end assembly54using the stay rods58.

Each fluid end section56and its various components are heavy and cumbersome. Various tools or lifting mechanisms may be used to assemble the fluid end assembly52and attach it to the power end assembly54, creating the high-pressure pump50.

Operation of Fluid End Assembly

Turning back toFIGS.11-13, in operation, retraction of the plunger240out of the housing60pulls fluid from the upper and lower suction bores133and134into the suction passages340within the fluid routing plug132. Fluid flowing through the suction passages340and into the axially-blind bore342pushes on the valve insert432of the suction valve280, causing the valve280to compress the spring446and move to an open position, as shown inFIG.11. When in the open position, fluid flows around the suction valve280and the suction valve guide282and into the open horizontal bore70within the second section74of the housing60.

Extension of the plunger240further into the housing60pushes against fluid within the open horizontal bore70and forces the fluid towards the suction surface332of the fluid routing plug132. Such motion also causes the suction valve280to move to a closed position, sealing the opening of the axially-blind bore342. Because the bore342is sealed, fluid is forced into the discharge passages360, as shown inFIG.12.

Fluid flowing through the discharge passages360contacts the valve insert432on the discharge valve138, causing the discharge valve138to compress the spring446and move into an open position. When in the open position, fluid flows around the discharge valve138and into the upper and lower discharge bores102and104. Fluid exiting the discharge passages360has a higher pressure than the fluid entering the housing60through the suction bores133and134.

During operation, the plunger240continually reciprocates within the housing60, pressuring all fluid drawn into the housing60through the suction bores133and134. Pressurized fluid exiting the housing60through the upper and lower discharge bores102and104is delivered to the upper and lower discharge manifolds109and117in communication with each of the fluid end sections56. Pressurized fluid within the discharge manifolds109and117is eventually delivered to the wellhead18, as shown inFIG.2.

Alternative Embodiments

Turning toFIGS.86-120, alternative embodiments of a fluid end section500and600are shown. For ease of reference, components included in the alternative embodiments that are identical or nearly identical to components included in the fluid end section56, shown inFIGS.3-85, will be given the same reference numbers.

With reference toFIGS.86-93, another embodiment of a fluid end section500is shown. The fluid end section500is identical to the fluid end section56, but it comprises another embodiment of a housing502. The housing502has the same general shape as the housing60, but the housing502is of single-piece construction. The housing502does not include multiple sections joined together by fasteners.

The housing502comprises opposed front and rear surfaces504and506joined by an outer intermediate surface508, as shown inFIGS.88and89. A horizontal bore510is formed within the housing502that interconnects the front and rear surfaces504and506, as shown inFIGS.88and89. The wall of the horizontal bore510is shaped identical to the wall of the horizontal bore70and is configured to receive the same inner components as the housing60, as shown inFIG.89. The only difference between the wall of the horizontal bore70and the horizontal bore510is that the first seal groove186is formed at the intersection of the base180and the side wall182of the first counterbore178, instead of in the center of the second side wall182, as shown inFIGS.89and90.

The outer intermediate surface508of the housing502comprises a first section512integrally joined to a second section514. The first section512is shaped identically to the first section72and comprises the plurality of passages86and corresponding notches82configured to receive a plurality of stay rods54in a one-to-one relationship, as shown inFIGS.86and87. The second section514of the housing502comprises a cylindrical portion516that transitions into the rear mounting flange152and the rear projecting portion156of the housing502, as shown inFIGS.88and93. Because the housing502is a single piece, the housing502does not include the front spacer sleeve76.

The cylindrical portion516of the second section514of the housing502is configured to house the same components as the second section74of the housing60, shown inFIG.89. The rear mounting flange152and rear portion156of the housing502are configured to mate with the rear spacer sleeve168, the stuffing box167, and the rear retainer209in the same manner as the fluid end section56, as shown inFIGS.88and89. The only difference between this area of the housing502and the housing60is that the second seal groove194is formed at the intersection of the base191and the side wall190of the second counterbore189, instead of in the center of the second side wall190, as shown inFIGS.88and91.

Continuing withFIGS.88and89, the second fasteners166extend through the rear mounting flange152, rear spacer sleeve168, stuffing box167, and rear retainer209in the same manner as the fluid end section56. The second fasteners166are secured on opposite ends255and269using the blind nuts253and the nuts268and corresponding washers272. While not shown, a reaction washer254and seal259may also be installed on each of the blind nuts253. The plunger packing210, the packing nut211, and the plunger240are installed within the fluid end section500in the same manner as the fluid end section56. When the fluid end section500is assembled, the ends255of the second fasteners166and the blind nuts253are in a spaced-relationship with and face the cylindrical portion516of the second section514of the housing502, as shown inFIGS.86-89.

Turning toFIGS.94-120, another embodiment of a fluid end section600is shown. The fluid end section600is similar to the fluid end section56but it includes another embodiment of a housing602and utilizes a retention plate604instead of the rear spacer sleeve168. The inner components of the housing602are identical to the housing502, shown inFIG.89. However, the housing602also includes a third counterbore606configured to receive a wear ring608that surrounds a portion of the fluid routing plug132, shown inFIGS.96-99.

With reference toFIGS.100-104, the housing602comprises opposed front and rear surfaces610and612joined by an outer intermediate surface614. A horizontal bore616is formed within the housing602and interconnects the front and rear surfaces610and612, as shown inFIGS.103and104. The housing602is of multi-piece construction. In contrast to the housing60, the housing602comprises three sections instead of two sections. However, the housing602does not utilize the front spacer sleeve76.

The housing602comprises a first section618joined to a second section620and a third section622by a plurality of first fasteners624, as shown inFIGS.102and104. Like the housing60, by making the housing602out of multiple sections618,620, and622, any one of the sections may be removed and replaced with a new section without replacing the rest of the housing602. The first fasteners624are identical to the first fasteners78but are longer to accommodate the three sections of the housing602, instead of the two included in the housing60, as shown inFIG.104.

Turning toFIGS.105-109, the first section618is positioned at the front end of the housing602and includes the front surface610. During operation, fluid within the first section618remains at relatively the same high pressure. Thus, the first section618is considered the static or constant high-pressure section of the housing602. The first section618is generally identical to the first section72of the housing60, but the first section618is shortened so that it does not include the upper and lower suction bores133and134. Likewise, the first section618only receives a portion of the discharge surface334of the fluid routing plug132, as shown inFIGS.96-99.

Like the first section72, the first section618comprises the plurality of passages86and corresponding notches82configures to receive a corresponding one of the stay rods54, as shown inFIGS.105and106. The first section618further comprises a rear surface628with a plurality of threaded openings626. Like the threaded openings96formed in the first section72, the threaded openings626are configured to receive the plurality of first fasteners624in a one-to-one relationship, as shown inFIG.104. Also formed within the rear surface628of the first section618are a plurality of dowel openings630configured to receive first alignment dowels632used to align the second section620on the first section618of the housing602, as shown inFIG.103.

The wall of the horizontal bore616of the first section618is the same as the first section72up to adjacent the rear surface628of the first section618. The third counterbore606is formed in the wall of the horizontal bore616and opens on the rear surface628of the first section618, as shown inFIGS.108and109. The third counterbore606is sized to receive the wear ring608and comprises a base634joined to a side wall636, as shown inFIGS.108and109. The side wall636may be tapered like the second counterbore189, shown inFIG.69. A third seal groove638is also formed at the intersection of the side wall636and the base634and is sized to receive an annular seal640. Like the seal195, the seal640prevents fluid from leaking around the wear ring608during operation. In alternative embodiments, the third seal groove638may be formed in the center of the side wall636, as shown inFIG.69.

When the wear ring608is installed within the third counterbore606, the wear ring608is positioned at the same location as the sealing surface142formed in the first section72of the housing60and shown inFIG.11. The wear ring608engages the first seal144installed within the fluid routing plug132, as shown inFIGS.96-99. During operation, the seal144wears against the wear ring608. If the wear ring608starts to erode, the wear ring608can be removed and replaced with a new wear ring608, thereby maintaining the integrity of the first section618of the housing602. Like the wear ring192, the wear ring608is made of a harder and more wear resistant material than that of the housing602. The wear ring608may be installed within the first section618of the housing602prior to assembling the housing602.

Continuing withFIG.103, the upper and lower discharge bores102and104are formed within the first section618of the housing602. Each discharge bore102and104includes the counterbore106and groove110also formed in the first section72of the housing60. A discharge fitting107is shown installed within each discharge bore102and104, as shown inFIG.96. Each discharge fitting107is attached to the first section618by installing a plurality of threaded fasteners115within the threaded openings114formed in the outer intermediate surface614, as shown inFIGS.96,105, and106. Each discharge fitting107interconnects a discharge conduit105and the upper or lower discharge manifold109or117, as shown inFIG.3.

With reference toFIGS.110-113, the second section620of the housing602is configured to be positioned between the first and third sections618and622and has a cylindrical cross-sectional shape. During operation, fluid pressure within the second section620remains at relatively the same pressure. The pressure is lower than that within the first section618. Thus, the second section620may be referred to as the static or constant low-pressure section of the housing602. The second section620comprises opposed front and rear surfaces644and646joined by a portion of the outer intermediate surface614and a portion of the horizontal bore616.

Formed within the second section620are a plurality of passages648. The passages648surround the horizontal bore616and interconnect the front and rear surfaces644and646, as shown inFIG.113. Each passage648is configured to receive a corresponding one of the first fasteners624used to secure the sections618,620, and622of the housing602together, as shown inFIG.104.

Also formed within the second section620are a plurality of dowel openings650, as shown inFIG.112. The dowel openings650are formed in the front surface644of the second section620. The dowel openings650align with the dowel openings630formed in the rear surface628of the first section618and are configured to receive a portion of the first alignment dowels632, as shown inFIG.103. Likewise, a plurality of dowel openings652are formed in the rear surface646of the second section620, as shown inFIG.112. The dowel openings652are configured to receive a portion of second alignment dowels654, as shown inFIG.103. The second alignment dowels654are configured to align the second section620and the third section622during assembly.

A first annular groove656is also formed in the front surface644of the second section620such that it surrounds the horizontal bore616, as shown inFIG.110. The first groove656is positioned between the horizontal bore616and the plurality of passages648and is configured to receive a first seal658, as shown inFIG.103. Likewise, a second annular groove660is formed in the rear surface646of the second section620and positioned between the horizontal bore616and the plurality of passages648, as shown inFIG.111. The second groove660is configured to receive a second seal662, as shown inFIG.103. The seals658and662shown in the figures are O-rings. In alternative embodiments, other types of seals known in the art may be used. During operation, the seals658and662prevent fluid from leaking between the first and second sections618and620and between the second and third sections620and622.

Continuing withFIG.103, the upper and lower suction bores133and134are formed within the second section620of the housing602. The suction bores133and134are each configured to receive one of the suction conduits136, as shown inFIG.96. Internal threads664are formed in a portion of each wall of each suction bore133and134. The internal threads664are configured to mate with external threads666formed on the outer surface of each suction conduit136. Instead of the internal threads664, a seal groove668is formed in each bore133and134for receiving a seal670sized to surround an extended portion671of each suction conduit136, as shown inFIG.96. During operation, the seal670prevents fluid from leaking between the suction bores133or134and the suction conduits136.

The wall of the horizontal bore616within the second section620is configured to receive a majority of the fluid routing plug132, as shown inFIGS.96-99. A small amount of clearance may exist between the wall of the horizontal bore616of the second section620and an outer surface of the fluid routing plug132.

Turning toFIGS.114-117, the third section622of the housing602is positioned at the rear end of the housing602and includes the rear surface612. The third section622has a generally cylindrical cross-sectional shape. Fluid pressure within the third section622varies during operation. Thus, the third section622may be referred to as the dynamic or variable pressure section of the housing602. The third section622is similar in size and shape to the second section514of the housing502, shown inFIG.88.

The third section622comprises a front surface672joined to the rear surface612of the housing602by a portion of the outer intermediate surface614and a portion of the horizontal bore616. The outer intermediate surface614of the third section622comprises a front mounting flange674and a rear mounting flange676. The mounting flanges674and676are separated by a medial portion678of the third section622. The mounting flanges674and676have a greater outer diameter than the medial portion678. The front mounting flange674further has a greater outer diameter than the rear mounting flange676. In contrast to the second section620of the housing602, the front and rear mounting flanges674and676formed in the third section622of the housing602are not spaced from the front and rear surfaces672and612of the third section622. Rather, each mounting flange674and676includes the corresponding front and rear surface672and612of the third section622.

The front mounting flange674is wider than that of the front mounting flange150formed in the second section74of the housing60, but like the front mounting flange150, the front mounting flange674is configured to receive the first fasteners624. A plurality of passages680are formed in the front mounting flange674that are positioned to align with the passages648formed in the second section620, as shown inFIG.104. A plurality of dowel openings682are also formed in the front surface672of the third section622for receiving the second alignment dowels654, as shown inFIG.103.

Like the rear mounting flange152, the rear mounting flange676comprises a plurality of passages684configured to receive the second fasteners166, as shown inFIG.97. Also like the rear mounting flange152, the rear mounting flange676comprises a plurality of threaded openings686configured to receive a corresponding third fastener688, as shown inFIG.99. The rear mounting flange676further comprises a plurality of dowel openings690configured to receive third alignment dowels692, as shown inFIG.98.

Continuing withFIGS.116and117, the third section622of the housing602further comprises the first counterbore178and the first seal groove186, like those shown inFIG.90. Likewise, the third section622comprises the second counterbore189and the second seal groove194like those shown inFIG.91. In alternative embodiments, the first and second seal grooves186and194may be positioned in the center of the side walls182and190of the corresponding counterbores178and189, like those shown inFIGS.16and17. The third section622is configured to receive the same components as the second section74of the housing60, as shown inFIGS.11-13and97.

With reference toFIGS.102-104, the housing602is assembled by threading a first end694of each of the first fasteners624into a corresponding one of the threaded openings626formed in the first section618. Once installed therein, the first fasteners624project from the rear surface628of the first section618. The second and third sections620and622may then be slid onto the fasteners624projecting from the first section618using the corresponding passages648and680. The first and second alignment dowels632and654help to further align the sections618,620, and622together during assembly. When the second and third sections620and622are installed on the fasteners624, a second end696projects from the front mounting flange674of the third section622and is positioned over the medial portion678of the third section622, as shown inFIGS.100and101. A nut208is installed on the second end696and torqued against the front mounting flange674, tightly securing the sections618,620, and622together. Prior to assembling the housing602, the wear ring192, the seal193, the seal195, the annular insert184, and the seal188are installed within the corresponding counterbores178and189.

Turning back toFIGS.94and95, the stuffing box167and the rear retainer209are attached to the rear surface612of the housing602. In contrast to the fluid end sections56and500, the fluid end section600does not utilize a rear spacer sleeve168. Instead, the retention plate604is positioned between the rear surface612of the housing602and a portion of the stuffing box167, as shown inFIGS.96-99.

With reference toFIGS.118and119, the retention plate604has a cylindrical cross-sectional shape and is sized to cover the rear surface612of the housing602and the wear ring192and the seal193, as shown inFIG.97. The retention plate604holds the wear ring192and the seal193within the housing602in the event the stuffing box167needs to be removed.

The retention plate604comprises opposed front and rear surface698and700joined by a central opening702formed therein. A plurality of first passages704are formed in the retention plate604and surround the central opening702of the plate604. The first passages704align with the passages684formed in the rear mounting flange676of the third section622and are configured to receive the plurality of second fasteners166, as shown inFIG.97.

A plurality of second passages706are also formed in the retention plate604. The second passages706align with the threaded openings686formed in the rear surface612of the housing602and are configured to receive the third fasteners688, as shown inFIG.99. A third fastener688is threaded into one of the threaded openings686and is turned until it sits flush with the rear surface700of the retention plate604. A plurality of dowel passages708are also formed in the retention plate604for receiving third alignment dowels692, as shown inFIG.98. The third alignment dowels692assist in properly aligning the retention plate604and the stuffing box167on the housing602during assembly.

Since fluid does not contact the retention plate604during operation, the retention plate604may be made of a different and less costly material than that of the housing602or the stuffing box167. For example, the retention plate604may be made of alloy steel, while the housing602and stuffing box167are made of stainless steel.

Continuing withFIG.97, after the retention plate604is attached to the rear surface612of the housing602, the stuffing box167and rear retainer209are attached to the housing602using the second fasteners166in the same manner as the fluid end sections56and500. The blind nuts253and nuts268and corresponding washers272are attached to opposite ends255and269of the second fasteners166. The reaction washers254are also shown installed on each of the blind nuts253, as shown inFIG.94. The plunger packing210and packing nut211are also installed within the stuffing box167and the rear retainer209in the same manner as the fluid end sections56and500. While not shown, the blind nuts253shown inFIG.97may also include the opening262for viewing the second fastener166.

As shown inFIGS.94and95, when the fluid end section602is assembled, the second ends696of the first fasteners624and corresponding nuts208and the first ends255of the second fasteners166and corresponding blind nuts253are in a spaced-relationship and face each other. Both ends696and255and corresponding nuts208and253are positioned between the front and rear mounting flanges674and676and both ends and corresponding nuts overlap the medial portion678of the third section622. When assembled, the second fasteners166extend along an axis that is parallel to a longitudinal axis710of the housing602, as shown inFIG.97.

The fluid end sections described herein have various embodiments of housings, inner components, and components attached to the various housings. While not specifically shown in a figure herein, various features from one fluid end section embodiment may be included in another fluid end section embodiment. One of skill in the art will appreciate that the various housing and components described herein may have different shapes and sizes, depending on the shape and size of the various components chosen to assemble each fluid end section.

One or more kits may be useful in assembling a fluid end assembly out of the various fluid end sections described herein. A single kit may comprise a plurality of one of the various embodiments of housings and fasteners described herein. The kit may further comprise a plurality of one or more of the various inner components described herein. The kit may even further comprise a plurality of one or more of the various components attached to the various housings described herein.

The various features and alternative details of construction of the apparatuses described herein for the practice of the present technology will readily occur to the skilled artisan in view of the foregoing discussion. It is to be understood that even though numerous characteristics and advantages of various embodiments of the present technology have been set forth in the foregoing description, together with details of the structure and function of various embodiments of the technology, this detailed description is illustrative only. Changes may be made in detail, especially in matters of structure and arrangements of parts within the principles of the present technology to the full extent indicated by the broad general meaning of the terms in which the appended claims are expressed.