(19) United States
`(12) Patent Application Publication (10) Pub. No.: US 2017/0218951 A1
`Graham et al.
`(43) Pub. Date:
`Aug. 3, 2017
`
`US 20170218951A1
`
`(54) FLUID END BLOCK FOR WELL
`STMULATION PUMP AND METHOD OF
`REMANUFACTURING THE SAME
`
`(71) Applicant: Caterpillar Inc., Peoria, IL (US)
`
`(72) Inventors: Curtis J. Graham, Peoria, IL (US);
`Daniel T. Cavanaugh, Chillicothe, IL
`(US)
`(73) Assignee: Caterpillar Inc., Peoria, IL (US)
`
`(21) Appl. No.: 15/012,522
`
`(22) Filed:
`
`Feb. 1, 2016
`
`Publication Classification
`
`(51) Int. Cl.
`F04B 53/16
`B23P6/04
`B24C I/00
`B05D I/02
`F04B 9/22
`F04B 53/10
`F04B 53/14
`
`
`
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`(2006.01)
`
`(2006.01)
`(2006.01)
`
`E2IB 43/26
`F04B 704
`(52) U.S. Cl.
`CPC ............ F04B 53/166 (2013.01): E2IB 43/26
`(2013.01); B23P6/04 (2013.01); B.24C I/00
`(2013.01); F04B 704 (2013.01); F04B 19/22
`(2013.01); F04B 53/10 (2013.01); F04B 53/14
`(2013.01); B05D 1/02 (2013.01); E2IB 43/267
`(2013.01)
`
`(57)
`
`ABSTRACT
`
`A method of remanufacturing a fluid end block of a well
`stimulation pump includes cleaning an interior Surface of a
`body of the fluid end block. The interior surface defines a
`chamber, a plunger passage in communication with the
`chamber, an intake passage in fluid communication with the
`chamber, and a discharge passage in fluid communication
`with the chamber. The interior surface is made from a base
`material. The interior surface of the fluid end block is
`cold-worked to produce a compressive residual stress layer
`within the body. A coating layer made from a non-metallic
`material is applied to at least a portion of the interior Surface
`of the body. The non-metallic material is different from the
`base material.
`
`Vulcan
`Ex. 1020
`Page 1 of 16
`
`

`

`Patent Application Publication
`Patent Application Publication
`
`Aug. 3, 2017. Sheet 1 of 7
`Aug. 3, 2017 Sheet 1 of 7
`
`US 2017/0218951A1
`US 2017/0218951 A1
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`Vulcan
`Ex. 1020
`Page 2 of 16
`
`

`

`Patent Application Publication
`
`Aug. 3, 2017. Sheet 2 of 7
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`US 2017/0218951A1
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`Vulcan
`Ex. 1020
`Page 3 of 16
`
`

`

`Patent Application Publication
`Patent Application Publication
`
`Aug. 3, 2017. Sheet 3 of 7
`Aug. 3, 2017 Sheet 3 of 7
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`US 2017/0218951A1
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`Ex. 1020
`Page 4 of 16
`
`

`

`Patent Application Publication
`atent Application
`Publication
`
`Aug. 3, 2017 Sheet 4 of 7
`Aug. 3, 2017 Sheet 4 of 7
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`US 2017/0218951A1
`US 2017/0218951 A1
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`
`Vulcan
`Ex. 1020
`Page 5 of 16
`
`

`

`Patent Application Publication
`Patent Application Publication
`
`Aug. 3, 2017. Sheet 5 of 7
`Aug. 3, 2017 Sheet 5 of 7
`
`US 2017/0218951A1
`US 2017/0218951 A1
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`
`Vulcan
`Ex. 1020
`Page 6 of 16
`
`

`

`Patent Application Publication
`
`Aug. 3, 2017 Sheet 6 of 7
`
`US 2017/0218951 A1
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`Vulcan
`Ex. 1020
`Page 7 of 16
`
`

`

`Patent Application Publication
`
`Aug. 3, 2017. Sheet 7 of 7
`
`US 2017/0218951A1
`
`700 N
`
`Clean an interior surface of a body of the fluid end
`block, the interior surface being made from a base
`material, and the interior surface defining a
`chamber, a plunger passage in communication
`with the chamber, an intake passage in fluid
`communication with the chamber, and a discharge
`passage in fluid communication with the chamber
`
`710
`
`Cold-work the interior surface of the fic endock
`to produce a compressive residual stress layer
`within the body
`
`
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`materia to at east a portion of the interior surface
`of the body, the non-metallic material being
`different from the lase lateria
`
`F.G. 7
`
`Vulcan
`Ex. 1020
`Page 8 of 16
`
`

`

`US 2017/02 18951 A1
`
`Aug. 3, 2017
`
`FLUID END BLOCK FOR WELL
`STMULATION PUMP AND METHOD OF
`REMANUFACTURING THE SAME
`
`TECHNICAL FIELD
`0001. This patent disclosure relates generally to well
`stimulation pump systems, and more particularly to fluid end
`blocks for a well stimulation pump system and methods for
`remanufacturing the same.
`
`BACKGROUND
`0002 Underground hydraulic fracturing can be per
`formed to increase or stimulate the flow of hydrocarbon fluid
`from a well. To conduct a fracturing process, a fracturing
`fluid, which typically contains a propping material (also
`referred to as a “proppant') dispersed in the fluid, is pumped
`at high pressure down the well-bore and into a hydrocarbon
`formation to split—or fracture—the rock formation along
`veins or planes extending from the well-bore. Once the
`desired fracture is formed, the fluid flow is reversed, and the
`liquid portion of the fracturing fluid is removed. The prop
`pants remain in place to prop the fracture in an open
`condition, preventing the stresses within the hydrocarbon
`formation from causing the opening to collapse.
`0003. The propping material, such as silica sand, for
`example, is typically provided in particle form. The prop
`pants Support the fractures in open positions, yet remain
`permeable to hydrocarbon fluid flow since they form a
`packed bed of particles with interstitial void spaces defined
`therebetween that permit fluid flow therethrough. Fractures
`that are propped open with proppant clusters can thus serve
`as new formation drainage areas and flow conduits from the
`formation to the well bore, thereby providing increased
`hydrocarbon production from the well.
`0004 Plunger pumps are commonly used in the oil and
`gas industry as well stimulation pumps for hydraulic frac
`turing applications. Plunger pumps have a fluid end and a
`power end that drives the fluid end. The fluid end of a
`conventional well stimulation pump system frequently has a
`limited service life because it is prone to break down after
`a certain amount of “wet fatigue' pressure cycles. The
`fracturing fluid can be corrosive and cause the corrosion of
`the internal surfaces of the fluid end. The corroded surface
`creates stress risers. Wet fatigue involves a failure process
`where cracks can propagate from these stress risers as a
`function of the cyclic stress until the cracks are significant
`enough to cause the failure of the fluid end.
`0005 U.S. Pat. No. 8,359,967 is entitled, “Fluid End
`Reinforced with a Composite Material.” The 967 patent is
`directed to a fluid end for a reciprocating pump that includes
`a base material that is less Subject to abrasion, corrosion,
`erosion and/or wet fatigue than conventional fluid end
`materials, such as carbon steel, and a reinforcing composite
`material for adding stress resistance and reduced weight to
`the fluid end.
`0006. There is a continued need in the art to provide
`additional solutions to extend the service life and/or facili
`tate the maintenance of well stimulation pump systems. For
`example, there is a continued need for remanufacturing
`techniques that produce a remanufactured fluid end block
`that is restored to a satisfactory operating condition for a
`renewed useful life of the remanufactured part with
`improved corrosion resistance.
`
`0007. It will be appreciated that this background descrip
`tion has been created by the inventors to aid the reader, and
`is not to be taken as an indication that any of the indicated
`problems were themselves appreciated in the art. While the
`described principles can, in some aspects and embodiments,
`alleviate the problems inherent in other systems, it will be
`appreciated that the scope of the protected innovation is
`defined by the attached claims, and not by the ability of any
`disclosed feature to solve any specific problem noted herein.
`
`SUMMARY
`0008. In embodiments, the present disclosure describes a
`fluid end block for a well stimulation pump. The fluid end
`block includes a body and a coating layer of a non-metallic
`material.
`0009. The body includes an interior surface which defines
`a chamber, a plunger passage in communication with the
`chamber, an intake passage in fluid communication with the
`chamber, and a discharge passage in fluid communication
`with the chamber. The interior surface is made from a base
`material. The body includes a compressive residual stress
`layer.
`0010. The coating layer is applied to at least a portion of
`the interior surface of the body. The coating layer is made
`from a non-metallic material which is different from the base
`material.
`0011. In another embodiment, a fluid end assembly for a
`well stimulation pump includes a body, an intake valve, a
`discharge Valve, a plunger, and a coating layer of a non
`metallic material. The body includes an interior surface
`which defines a chamber, a plunger passage in communica
`tion with the chamber, an intake passage in fluid commu
`nication with the chamber, and a discharge passage in fluid
`communication with the chamber. The interior surface is
`made from a base material. The body includes a compressive
`residual stress layer.
`0012. The intake valve is disposed within the intake
`passage of the body. The intake valve is configured to
`selectively move between an intake closed position, in
`which the intake valve occludes the intake passage, and an
`intake open position, in which the intake valve permits fluid
`flow therethrough.
`0013 The discharge valve is disposed within the dis
`charge passage of the body. The discharge valve is config
`ured to selectively move between a discharge closed posi
`tion, in which the discharge valve occludes the discharge
`passage, and a discharge open position, in which the dis
`charge valve permits fluid flow therethrough.
`0014. The plunger is disposed within the plunger passage
`Such that the plunger is reciprocally movable over a range of
`travel including a Suction stroke and a discharge stroke. The
`plunger draws the intake valve to the intake open position to
`open the intake passage during the Suction stroke. The
`plunger moves the intake valve to the intake closed position
`to occlude the intake passage and moves the discharge valve
`to the discharge open position during the discharge stroke.
`0015 The coating layer is applied to at least a portion of
`the interior surface of the body. The coating layer is made
`from a non-metallic material which is different from the base
`material.
`0016. In yet another embodiment, a method of remanu
`facturing a fluid end block of a well stimulation pump is
`described. An interior surface of a body of the fluid end
`block is cleaned. The interior surface is made from a base
`
`Vulcan
`Ex. 1020
`Page 9 of 16
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`

`

`US 2017/02 18951 A1
`
`Aug. 3, 2017
`
`material. The interior Surface defines a chamber, a plunger
`passage in communication with the chamber, an intake
`passage in fluid communication with the chamber, and a
`discharge passage in fluid communication with the chamber.
`0017. The interior surface of the fluid end block is
`cold-worked to produce a compressive residual stress layer
`within the body. A coating layer made from a non-metallic
`material is applied to at least a portion of the interior Surface
`of the body. The non-metallic material is different from the
`base material.
`0018. Further and alternative aspects and features of the
`disclosed principles will be appreciated from the following
`detailed description and the accompanying drawings. As
`will be appreciated, the devices, systems, and methods
`disclosed herein are capable of being carried out in other and
`different embodiments, and capable of being modified in
`various respects. Accordingly, it is to be understood that
`both the foregoing general description and the following
`detailed description are exemplary and explanatory only and
`do not restrict the scope of the appended claims.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`0.019
`FIG. 1 is a schematic side elevational view of an
`embodiment of a well stimulation pump system constructed
`in accordance with principles of the present disclosure.
`0020 FIG. 2 is a schematic top plan view of the well
`stimulation pump system of FIG. 1.
`0021
`FIG. 3 is a schematic front elevational view of the
`well stimulation pump system of FIG. 1.
`0022 FIG. 4 is a cross-sectional view, taken along line
`IV-IV in FIG.3, of the well stimulation pump system of FIG.
`1.
`0023 FIG. 5 is a perspective view of a fluid end block of
`the well stimulation pump system of FIG. 1, the fluid end
`block being constructed in accordance with principles of the
`present disclosure.
`0024 FIG. 6 is a cross-sectional view, taken along line
`V-V in FIG. 5, of the fluid end block of FIG. 5.
`0025 FIG. 7 is a flowchart illustrating steps of an
`embodiment of a method of remanufacturing a fluid end
`block for a well stimulation pump system following prin
`ciples of the present disclosure.
`0026. It should be understood that the drawings are not
`necessarily to Scale and that the disclosed embodiments are
`Sometimes illustrated diagrammatically and in partial views.
`In certain instances, details which are not necessary for an
`understanding of this disclosure or which render other
`details difficult to perceive may have been omitted. It should
`be understood, of course, that this disclosure is not limited
`to the particular embodiments illustrated herein.
`
`DETAILED DESCRIPTION
`0027 Embodiments of well stimulation pump systems,
`fluid end block assemblies, and methods of remanufacturing
`fluid end blocks are disclosed herein. In embodiments, a
`method of remanufacturing a fluid end block for a well
`stimulation pump system following principles of the present
`disclosure can include applying a coating layer of a non
`metallic material upon an interior surface of the fluid end
`block. In embodiments, the non-metallic material from
`which the coating layer is made can have a corrosion
`resistance that is greater than that of the base material from
`which the fluid end block is made.
`
`0028. In embodiments, the coating layer of non-metallic
`material (e.g., an epoxy, an elastomer Such as rubber, etc.)
`can be applied via any Suitable technique. For example, in
`embodiments, the coating layer of non-metallic material can
`be applied to the interior surface of the fluid end block by
`being sprayed upon the interior surface of the fluid end
`block. In other embodiments, the coating layer of non
`metallic material can be in the form of a solid liner that is
`separately made and is applied to the interior Surface by
`being inserted into the fluid end block and placed in con
`tacting relationship with the interior Surface.
`0029 Turning now to the Figures, there is shown in
`FIGS. 1-3 an exemplary embodiment of a well stimulation
`pump system 20 constructed according to principles of the
`present disclosure. The well stimulation pump system 20 can
`be used to pump high pressure fracturing fluid into a well for
`the recovery of oil and/or gas contained within a Subterra
`nean hydrocarbon formation.
`0030 The well stimulation pump system 20 includes a
`power end 23 and a fluid end 25, which is coupled to the
`power end 23. The well stimulation pump system 20 illus
`trated in FIG. 1 is in the form of a triplex pump that includes
`three plungers 27. Accordingly, the fluid end includes three
`pumping chamber assemblies 30, 31, 32. It will be under
`stood by one skilled in the art that, in other embodiments, a
`well stimulation pump system constructed according to
`principles of the present disclosure can have different forms.
`0031. The power end 23 includes a motor assembly 35
`disposed within a housing 37. The motor assembly 35 is
`configured to selectively drive the plungers 27. The motor
`assembly 35 can be configured to reciprocally move the
`plungers 27 to pressurize a working fluid (e.g., a fracking
`fluid) in the fluid end 25. In embodiments, the motor
`assembly 35 can have any suitable arrangement. In embodi
`ments, the motor assembly 35 includes a Suitable engine,
`Such as, a diesel engine, for example, and a transmission
`configured to convert the rotational movement of the engine
`to reciprocal axial movement of the plungers 27. In embodi
`ments, a well stimulation pump system constructed accord
`ing to principles of the present disclosure can include any
`suitable power end, as will be understood by one skilled in
`the art.
`0032. In embodiments, the fluid end 25 comprises at least
`one pump container configured to hold a Supply of fluid that
`is drawn therein by the movement of a respective plunger 27
`over a Suction stroke and to discharge pressurized fluid
`therefrom that is pressurized by the reciprocal movement of
`the plungers over a power stroke. The fluid end 25 can
`include a fluid end block 40, an inlet conduit 41, and a
`high-pressure outlet coupling 43.
`0033. In embodiments, the fluid end block 40 defines one
`or more internal pumping cavities each configured to inter
`act with a respective plunger 27 to draw a working fluid
`(e.g., fracturing fluid) therein and to discharge pressurized
`working fluid therefrom. In the illustrated embodiment, the
`fluid end block 40 defines three pumping cavities 47, 48, 49
`(see FIG. 5) which respectively house the three pumping
`chamber assemblies 30, 31, 32 therein. The fluid end block
`40 includes a mounting flange 51 which can be disposed
`proximate the power end 23. The mounting flange 51 can be
`configured to receive a plurality of fasteners 53 therethrough
`for connecting the fluid end 25 to the power end 23. In
`embodiments, other Suitable connection techniques can be
`used to secure the fluid end 25 to the power end 23.
`
`Vulcan
`Ex. 1020
`Page 10 of 16
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`

`

`US 2017/02 18951 A1
`
`Aug. 3, 2017
`
`0034) Referring to FIGS. 1, 3, and 5, the inlet conduit 41
`is in fluid communication with each of the pumping cavities
`47, 48, 49 of the fluid end block 40. The inlet conduit 41 can
`be placed in fluid communication with a Supply of fracturing
`fluid for selective delivery to each pumping cavity of the
`fluid end block 40 during operation of the well stimulation
`pump system 20. The inlet conduit 41 as shown in FIG. 1 is
`in the form of a cylindrical tube which is in fluid commu
`nication with all three pumping cavities 47, 48, 49 defined
`by the fluid end block 40 in the illustrated embodiment. In
`other embodiments, the inlet conduit 41 can have a different
`configuration as will be appreciated by one skilled in the art.
`0035) Referring to FIGS. 1-3, the high-pressure outlet
`coupling 43 is mounted to the center pumping chamber
`assembly 30. The high-pressure outlet coupling 43 is con
`figured to dispense pressurized working fluid (e.g., pressur
`ized fracturing fluid) from the fluid end block 40 of the fluid
`end 25 for delivery to a working site. For example, in
`embodiment, a conduit (not shown) can be coupled to the
`high-pressure outlet coupling 43 such that the conduit is
`configured to deliver high-pressure fracturing fluid to a
`Subterranean location via a well. In embodiments, the high
`pressure outlet coupling 43 can have any suitable configu
`ration (e.g., either a male connector or a female connector).
`0036. During use, the fluid end 25 receives a working
`fluid (e.g., a fracturing fluid) at a low pressure and dis
`charges it at a high pressure. The pressurization of the
`fracturing fluid within the fluid end 25 is caused by the
`plungers 27 as directed by the motor assembly 35 of the
`power end 23. The plungers 27 move away from the fluid
`end 25 during a suction stroke to draw low-pressure fluid
`through the inlet conduit 41 into the pumping cavities 47, 48.
`49 of the fluid end 25 from the supply of fracturing fluid, and
`the plungers 27 move toward the fluid end 25 during a power
`stroke to pressurize the fluid within the fluid end 25 and to
`discharge the pressurized fracturing fluid from the fluid end
`25 out through the high-pressure outlet coupling 43.
`0037. It should be understood that, in other embodiments,
`the well stimulation pump system 20 can have different
`forms. For example, in other embodiments, a well stimula
`tion pump system constructed according to principles of the
`present disclosure can be in the form of a different type of
`multiplex reciprocating pump. For example, in other
`embodiments, the well Stimulation pump system constructed
`according to principles of the present disclosure can be in the
`form of a quintuplex pump that includes five plungers and a
`fluid end with five pumping chamber assemblies.
`0038. In addition, in still other embodiments, a well
`stimulation pump system constructed according to prin
`ciples of the present disclosure can include a fluid end that
`is in the form of a monoblock fluid end that includes a single
`pumping chamber for use with a single plunger. In still other
`embodiments, the fluid end can include a plurality of modu
`lar fluid end blocks that are connected together using any
`Suitable technique (e.g., a plurality of threaded fasteners and
`tie rods). Each modular fluid end block can include at least
`one pumping chamber and a corresponding number of
`plungers can be provided.
`0039 Referring to FIG. 4, the center pumping chamber
`assembly 30 of the fluid end 25 is shown disposed in the
`center pumping cavity 47 defined by the fluid end block 40.
`The two side pumping chamber assemblies 31, 32 of the
`fluid end 25 are substantially identical to the one shown in
`FIG. 4 and are disposed in the two side pumping cavities 48.
`
`49, respectively. It should be understood, therefore, that the
`description of one pumping chamber assembly is applicable
`to the other pumping chamber assemblies, as well. The
`center pumping chamber assembly 30 includes an intake
`valve 55, a discharge valve 57, the plunger 27, a plug 58, and
`the high-pressure outlet coupling 43.
`0040. Referring to FIGS. 4 and 6, the fluid end block 40
`includes a body 69 having an interior surface 70 which
`defines a chamber 72, a plunger passage 74 in communica
`tion with the chamber, an intake passage 75 in fluid com
`munication with the chamber, and a discharge passage 77 in
`fluid communication with the chamber 72. The chamber 72
`is configured to receive fracturing fluid which is drawn in
`from the intake passage 75 for the plunger 27 to effect high
`pressurization of the fracturing fluid in the chamber 72. The
`pressurized fracturing fluid can be discharged from the fluid
`end 25 through the discharge passage 77. Referring to FIG.
`4, the pumping chamber assembly 30 of the fluid end 25 is
`configured to cyclically draw working fluid into the chamber
`72, pressurize the working fluid in the chamber 72, and
`discharge it therefrom to be delivered to a worksite, such as
`a Subterranean hydrocarbon formation, for example.
`0041 Referring to FIGS. 4-6, the fluid end block 40
`defines a common cross-bore discharge passage 79 which is
`in fluid communication with the discharge passage 77 of
`each of the pumping cavities 47, 48, 49 such that the
`pressurized fracturing fluid flowing through any one of the
`discharge passages 77 of the fluid end block 40 can be
`diverted to the high-pressure outlet coupling 43 positioned
`in the discharge passage 77 of the center pumping cavity 47.
`0042. Referring to FIG.4, the intake valve 55 is disposed
`within the intake passage 75 of the fluid end block 40. The
`intake valve 55 is configured to selectively move between an
`intake closed position (shown in FIG. 4), in which the intake
`valve 55 occludes the intake passage 75, and an intake open
`position (upwardly displaced from the position shown in
`FIG. 4), in which the intake valve permits fluid flow there
`through. An intake biasing mechanism 82, Such as a spring,
`for example, can be provided to bias the intake valve 55
`outwardly from the chamber 72 to the intake closed position.
`0043. The intake valve 55 is configured to selectively
`move to the open position in response to a negative pressure
`differential within the chamber 72 to allow working fluid to
`enter the chamber 72 through the intake valve 55 when the
`pressure in the chamber 72 is sufficiently less than on the
`other side of the intake valve 55. The negative pressure
`within the chamber 72 can be created by the plunger 27
`moving outwardly relative to the chamber 72 in a suction
`direction 84. Once the negative pressure differential between
`the chamber 72 and the intake passage 75 on the outside of
`the intake valve 55 is at a sufficient level to overcome the
`biasing force of the intake biasing mechanism 82, the intake
`valve 55 can be drawn inwardly in response to the negative
`pressure within the chamber to move the intake valve 55 to
`the intake open position to open the intake passage 75. In
`embodiments, the threshold negative pressure within the
`chamber 72 for opening the intake valve 55 can be varied.
`0044) The discharge valve 57 is disposed within the
`discharge passage 77 of the fluid end block 40. The dis
`charge valve 57 is configured to selectively move between
`a discharge closed position (shown in FIG. 4), in which the
`discharge valve 57 occludes the discharge passage 77, and a
`discharge open position (downwardly displaced from the
`position shown in FIG. 4), in which the discharge valve 57
`
`Vulcan
`Ex. 1020
`Page 11 of 16
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`US 2017/02 18951 A1
`
`Aug. 3, 2017
`
`permits fluid flow therethrough. A discharge biasing mecha
`nism 85. Such as a spring, for example, can be provided to
`bias the discharge valve 57 inwardly toward the chamber 72
`to the discharge closed position which keeps the discharge
`passage 77 occluded.
`0045. The discharge valve 57 is configured to selectively
`move to the open position in response to a positive pressure
`differential within the chamber 72 to allow pressurized
`working fluid to leave the chamber 72 through the discharge
`valve 57 when the pressure in the chamber 72 is sufficiently
`greater than on the other side of the discharge valve 57. The
`positive pressure within the chamber 72 can be created by
`the plunger 27 moving inwardly relative to the chamber 72
`in a power direction 87, which is in opposing relationship to
`the suction direction 84. Once the positive pressure differ
`ential between the chamber 72 and the discharge passage 77
`on the outside of the discharge valve 57 is at a sufficient level
`to overcome the biasing force of the discharge biasing
`mechanism 85, the discharge valve 57 can be urged out
`wardly in response to the positive pressure within the
`chamber 72 to move the discharge valve 57 outwardly to the
`discharge open position. In embodiments, the threshold
`positive pressure within the chamber 72 for opening the
`discharge valve 57 can be varied.
`0046. The plunger 27 is disposed within the plunger
`passage 74 such that the plunger 27 is reciprocally movable
`over a range of travel including a Suction stroke and a
`discharge stroke. The plug 58 is threadedly engaged with the
`interior surface 70 of the fluid end block 40 at an end of the
`plunger passage 74 opposite the plunger 27. The plug 58 can
`be removed from the fluid end block 40 to provide selective
`access to the chamber 72. In embodiments, the plug 58 can
`have a different configuration and can be mounted to the
`fluid end block 40 using a different technique, as will be
`appreciated by one skilled in the art.
`0047. The plunger 27 can be sealingly engaged with the
`fluid end block 40 of the fluid end 25 to substantially prevent
`working fluid from flowing out of the chamber 72 past the
`plunger 27 through the plunger passage 74. In embodiments,
`one or more seal members 88 can be provided to effect the
`sealing relationship. In embodiments, both the seal member
`88 and the plug 58 can have a suitable o-ring interposed
`between an exterior surface thereof and the interior surface
`70 to provide a sealed interface.
`0048. In use, the plunger 27 can move outwardly relative
`to the chamber 72 in the suction direction 84 to effect
`negative pressurization in the chamber to draw the intake
`valve 55 to the intake open position to open the intake
`passage 75 during the Suction stroke. A source of fracturing
`fluid can be in fluid communication with the intake passage
`75 via the inlet conduit 41. The source of fracturing fluid can
`be at a relatively low pressure that is not sufficient to
`overcome the biasing force of the intake biasing mechanism
`82, but is operable to propel the source of fracturing fluid
`into the chamber 72 once the plunger 27 draws the intake
`valve 55 to the intake open position. The discharge valve 57
`remains in the discharge closed position during the Suction
`stroke.
`0049. After the suction stroke is completed, the plunger
`27 can move inwardly relative to the chamber in the power
`direction 87 during the power stroke to effect positive
`pressurization in the chamber to pressurize the fracturing
`fluid in the chamber. In response to the positive pressure
`generated within the chamber, the intake biasing mechanism
`
`82 is allowed to urge the intake valve 55 back to the intake
`closed position to occlude the intake passage 75, and the
`discharge valve 57 moves outwardly to the discharge open
`position Such that the pressurized fracturing fluid in the
`chamber 72 flows through the discharge valve 57 through
`the discharge passage 77 to the well bore site. During the
`power stroke, the intake valve 55 remains in the intake
`closed position.
`0050. The plunger 27 can reciprocally move over the
`Suction stroke and the power stroke to periodically draw
`fracturing fluid through the intake passage 75 into the
`chamber 72 from the source of fracturing fluid and to
`discharge fracturing fluid from the chamber 72 into the
`discharge passage 77 for delivery to the well bore site. With
`the continued reciprocal movement of the plunger 27, the
`fracturing fluid is alternately drawn into the chamber 72 and
`discharged therefrom at relatively higher pressure.
`0051. The plungers 27 associated with the side pumping
`chamber assemblies 31, 32 can operate in a similar manner.
`In embodiments, the well stimulation pump system 20 can
`be configured such that each plunger 27 of the three pump
`ing chamber assemblies 30, 31, 32 reciprocally moves such
`that it is out of phase with the other two plungers 27. The
`pressurized fracturing fluid discharged from each of the side
`pumping chamber assemblies 31, 32 can be fed to the center
`pumping chamber assembly 30 via the common cross-bore
`discharge passage 79 which is in fluid communication with
`the discharge passage 77 of each of the pumping chamber
`assemblies 30, 31, 32. The discharge passage 77 of each of
`the side pumping chamber assemblies 31, 32 can have a plug
`89 threadedly secured thereto (see FIG. 2) to direct the
`pressurized fracturing fluid from the side pumping chamber
`assemblies 31, 32 into the common cross-bore discharge
`passage 79 and out the high-pressure outlet coupling 43
`secured in the discharge passage 77 of the center pumping
`chamber assembly 30 to the well bore site.
`0052 Referring to FIGS. 5 and 6, the fluid end block 40
`of the well stimulation pump system 20 is shown. The fluid
`end block 40 includes the body 69 and a coating layer 90 of
`a non-metallic material applied to the body 69.
`0053 Referring to FIG. 5, the body 69 substantially
`defines the pumping cavities 47, 48, 49 and the common
`cross-bore discharge passage 79. In embodiments, at least
`one cover plate can be secured to the body 69 to close off a
`respective end of the common cross-bore discharge passage
`79. The body 69 can also include the mounting flange 51.
`0054. In embodiments, the body 69 can be made using
`any suitable technique, as will be appreciated by one skilled
`in the art. For example, in embodiments, the body 69 can
`have a unitary construction. In embodiments, a body blank
`can be made from a piece of material and then machined to
`final size and configuration to form the body 69. For
`example, in embodiments, the body 69 can comprise a
`high-strength steel forging, which can be machined to help
`define the pumping cavities 47, 48, 49 and the common
`cross-bore discharge passage 79. In embodiments, th