Fluid end with transition surface geometry

Abstract

The invention relates to a fluid end with transition surface geometry. A fluid end of the reciprocating pump includes a plurality of apertures formed therein, and adjacent apertures intersect one another. An intersection corner is formed at the intersection of two adjacent holes, and the corner is a position where high stress concentration occurs during operation of the reciprocating pump. The at least one aperture includes a first tapered portion and a second tapered portion. The first tapered portion increases a cross-sectional area of the bore toward the intersecting bore to reduce stress concentration on the intersecting corner. The second tapered portion reduces the cross-sectional area of the bore to provide a shoulder having an extended arc length and forming a groove. The extended arc length of the shoulder increases the available surface area to secure the valve holder within the recess.

Description

Technical Field

[0001] The present invention relates to the field of high-pressure reciprocating pumps, and more particularly to the fluid end of a high-pressure reciprocating pump, the fluid end including a groove in which a spring retainer is received. Background Art

[0002] High-pressure reciprocating pumps are commonly used to deliver high-pressure fluids during soil drilling operations. The reciprocating pump includes a fluid end defining a plurality of different internal bores, with adjacent bores intersecting. In a fluid end having intersecting bores, the corners where the bores intersect are typically stress concentration points. The high stress is caused by the internal pressure in the pump and the fluid being pumped. The stress concentration at the intersecting corners adversely affects the fatigue life of the pump fluid end and the quality of the finished fluid end housing or casing. A typical practice is to hand-grind within the transition radius at the intersecting corners in an attempt to reduce the stress at the corners.

[0003] In a fluid end having intersecting bores, non-uniform intersecting corners are formed. As a result, personnel must hand-finish the corners into a rounded shape to soften the transition from one bore to an adjacent bore. The hand-finished radius introduces a significant amount of irregularity from fluid end to fluid end, and there are also high physical requirements for the hand-finisher. Additionally, the hand-finishing process increases the cost and time of manufacturing and machining the fluid end. In some cases, the corners and / or the process of manufacturing the corners have been improved, which has extended the life of the fluid end. However, such techniques may make it difficult to install valve retainers (e.g., suction valve spring retainers), such as those disclosed in U.S. Patent Nos. 7,186,097 and 9,732,746, which are incorporated herein by reference in their entireties. Accordingly, there is a continuing need for further improvements. Summary of the Invention

[0004] The present application relates to a fluid end of a reciprocating pump, the fluid end including a housing defining a plurality of bores extending therethrough. Adjacent bores intersect each other at an intersection bore, and an intersection corner is formed at the intersection of two adjacent bores, which is a location where high stress concentration occurs during the operation of the pump. One of the bores has a first tapered portion and a second tapered portion, the first tapered portion being configured to provide a transition for reducing stress concentration at the intersection corner, and the second tapered portion forming a shoulder with the adjacent bore. The shoulder formed by the bores together produces an arc length long enough to secure a retainer therein. Accordingly, the retainer support within the intersection bore is improved, while the influence and concentration of stress are reduced by the tapered portions of the bores, thereby improving or extending the life of the material in the intersection corners of the fluid end. The foregoing advantages and features will become apparent from the accompanying drawings and the detailed description.

[0005] In one embodiment, the fluid end includes a first hole that extends through the fluid end and has a first main cylindrical portion and a tapered portion; a second hole that extends through the fluid end and has a second main cylindrical portion; and a cross hole where the first hole intersects the second hole. The second main cylindrical portion of the second hole terminates at the cross hole to form a shoulder in the cross hole, and the tapered portion of the first hole and the second main cylindrical portion of the second hole together define a peak that extends inwardly into the cross hole.

[0006] In another embodiment, a method of manufacturing a fluid end includes: forming a first hole having a main cylindrical portion; and forming a second hole to intersect the first hole at a cross hole in the fluid end. Forming the second hole includes forming a tapered portion of the second hole that decreases the cross-sectional area of the second hole along the tapered portion toward the cross hole. The tapered portion and the main cylindrical portion together define a peak that extends inwardly into the cross hole.

[0007] In another embodiment, the fluid end includes a first hole having a cylindrical portion and a second hole that extends through the fluid end and intersects the first hole at a cross hole. The first hole includes a first tapered portion that increases the cross-sectional area of the second hole along the first tapered portion toward the cross hole, the first hole includes a second tapered portion that decreases the cross-sectional area of the second hole along the second tapered portion toward the cross hole, and the second tapered portion abuts the main cylindrical portion of the first hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] To complete the description and to better understand the present application, a set of drawings is provided. The drawings form an integral part of the specification and illustrate embodiments of the present application, which should not be construed as limiting the scope of the invention but merely as examples. The drawings include the following figures:

[0009] Figure 1A is a perspective view of a prior art reciprocating pump including a fluid end.

[0010] Figure 1B is a schematic side cross-sectional view of a fluid end of another prior art reciprocating pump.

[0011] Figure 2A is a schematic isometric cross-sectional view of yet another prior art fluid end that includes a spring retainer and a retainer groove configured to receive the spring retainer.

[0012] Figure 2B and Figure 2C is Figure 2A an additional schematic cross-sectional view of the fluid end of

[0013] Figure 3 is a schematic side cross-sectional view of another prior art fluid end.

[0014] Figure 4 and Figure 5 shows a top cross-sectional view of a fluid end having the cross-hole geometry according to an exemplary embodiment of the present invention.

[0015] Figure 6 shows a bottom cross-sectional view of another fluid end having the cross-hole geometry according to an exemplary embodiment of the present invention.

[0016] Figure 7 shows Figure 6 a perspective cross-sectional view of the fluid end.

[0017] Figure 8 shows a side cross-sectional view of yet another fluid end having the cross-hole geometry according to an exemplary embodiment of the present invention.

[0018] Figure 9 shows the path of a tool for forming the cross-hole geometry according to an exemplary embodiment of the present invention.

[0019] Figure 10 and Figure 11 show cross-sectional views of a prior art fluid end and a fluid end having the cross-hole geometry according to the present invention, respectively.

[0020] Figure 12 shows a method of manufacturing a fluid end having the cross-hole geometry according to an exemplary embodiment of the present invention.

[0021] Throughout this disclosure, the same reference numerals are used to identify the same elements. Detailed Description

[0022] The following description is not restrictive and is merely for describing the general principles of the present invention. Embodiments of the present invention will be described by way of example with reference to the above figures showing the elements and results according to the present invention.

[0023] Generally, the present application relates to the fluid end of a reciprocating pump. Each of the different embodiments of the fluid end of the present invention has a plurality of holes formed therein, and adjacent holes intersect each other. The intersection of two adjacent holes forms an intersection corner, which is a location where high stress concentration occurs during the operation of the pump. The specific shape and geometry of the intersection corner determine the effect of stress and the degree of stress concentration on the intersection corner. By improving the shape and geometry of the intersection corner, the effect and concentration of stress can be reduced, thereby improving or extending the life of the material in the intersection corner of the fluid end. Using the technology proposed by the present invention, the novel geometry reduces the stress at one or more intersection corners, while reducing the amount of manual finishing required and increasing the circumferential engagement between the fluid end and a valve retainer (e.g., a valve spring retainer) installed in the fluid end. Additionally, these advantages can be achieved when a hole closure element (e.g., a plug) extends into the cross-hole / pumping chamber by a minimal amount.

[0024] As detailed herein, the geometry of the present invention provides a tapered section at the transition region between a first hole (e.g., a vertical hole) and a second hole (e.g., a horizontal hole). When viewed from above through a horizontal cross-sectional view, the new geometry resembles an M shape or an "M-shaped configuration". The tapered section reduces the amount of material that needs to be manually removed (e.g., by hand finishing) from the pumping chamber. Using less manual activity (hand finishing) and more processing time improves the consistency of the finished fluid end product and simplifies the manufacture of the fluid end, making the geometry of the present invention superior to currently available hand-finished products. The tapered section also increases the fatigue life of the fluid end of the reciprocating pump and the quality of the finished fluid end block. However, the technology proposed by the present invention does not add a significant cost to the machining of the fluid end or adversely affect the usability of the fluid end. Additionally, the tapered section increases the surface area available for engagement with the valve retainer. For example, the taper can form at least a part of a ledge such that the ledge has an increased arc length to provide a groove that can better capture the valve retainer. Thus, the tapered section improves the fixation of the valve retainer within the fluid end.

[0025] To best understand the technology proposed by the present invention, it is important to understand the operation of the fluid end and certain characteristics that develop over time. Therefore, Figure 1A and Figure 1B an existing fluid end is shown and its parts and components are described at a relatively high level. Then, Figures 2A - 2CAn existing fluid end is shown to demonstrate how certain retainers (e.g., spring retainers) are installed and fixed within the fluid end to support a biased valve in the inlet hole section of the fluid end. This fluid end and its components are shown and described in more detail in U.S. Patent 9,732,746, which is incorporated herein by reference in its entirety. However, for the sake of completeness, certain aspects of this patent are also discussed in the present invention. At the same time, Figure 3 Another existing fluid end is shown to demonstrate that the pumping chamber can be modified to improve wear characteristics, manufacturability, and other advantages, but these modifications can also achieve advantages by incorporating the features of the embodiments disclosed in the present invention. More details about such existing embodiments can be found in U.S. Application Nos. 18 / 326,312 and 17 / 972,717 filed on May 31, 2023, and October 25, 2022, respectively. The disclosures of each of these applications are hereby incorporated by reference in their entirety. In addition, for the sake of completeness, certain aspects of these applications are also discussed in the present invention. Further, other examples of pump fluid ends are disclosed in U.S. Patent Nos. 9,383,015 and 10,337,508, and the disclosures of each of these patents are also incorporated by reference in their entirety into the present invention.

[0026] That is to say, Figure 1A An existing reciprocating pump 100 of the prior art is shown. The reciprocating pump 100 includes a power end 102 and a fluid end 104. The power end 102 includes a crankshaft that drives a plurality of reciprocating elements within the fluid end 104 to pump fluid at high pressure. Generally, the power end 102 is capable of generating a force sufficient to cause the fluid end 104 to deliver high-pressure fluid to a soil drilling operation. For example, the power end 102 can be configured to support a hydraulic fracturing (i.e., fracking) operation, in which a fracturing fluid (e.g., a mixture of water and sand) is injected into a rock formation at high pressure to allow extraction of natural oil and gas from the rock formation. However, for clarity, this example is not intended to be limiting, and the present application can be applied to fracking and drilling operations as well as other operations.

[0027] Typically, the reciprocating pump 100 can be quite large and can be supported, for example, by a semi-tractor truck (“semi-trailer”) that can move the reciprocating pump 100 to or from a well. Specifically, in some cases, when the reciprocating pump 100 needs maintenance, the semi-trailer can move the reciprocating pump 100 away from the well. However, typically the reciprocating pump 100 is only moved away from the well when a replacement pump (and associated semi-trailer) is available to be moved to the appropriate location at the well, which can be rare. Thus, typically, the reciprocating pump is shut down at the well and maintenance is performed while the reciprocating pump 100 remains on the well. If not used for such maintenance, the reciprocating pump 100 can operate continuously to pump natural oil and gas (or perform any other operation). Thus, any improvement that extends the life of the components of the reciprocating pump 100 (especially typical “wear” components) and extends the time between maintenance operations (i.e., between downtimes) is highly desirable.

[0028] Still referring to Figure 1A , but now in combination with Figure 1B , in various embodiments, the fluid end 104 can have different shapes and / or have different features, but can still generally perform the same functions, define similar structures, and accommodate similar components. To illustrate possible shape variations, Figure 1B shows a side cross-sectional view of a fluid end 104' having different internal and external shapes compared to the fluid end 104. However, since the fluid end 104 and the fluid end 104' have many operational similarities, Figure 1A and Figure 1B are labeled with the same reference numerals and both are described with reference to these common reference numerals.

[0029] Figure 1B The cross-sectional view of Figure 1B is taken along the central axis of one reciprocating element 202 included in the reciprocating pump 100. Thus, although Figure 1B shows a single pumping chamber 208, it should be understood that the fluid end 104 can include a plurality of pumping chambers 208 arranged side by side. In fact, in at least some embodiments (e.g., Figure 1AIn the embodiment of (), the housing 206 of the fluid end 104 forms a plurality of pumping chambers 208, and each chamber 208 includes a reciprocating element 202 (e.g., a plunger) that reciprocates within the housing 206. However, the side-by-side pumping chambers 208 do not have to be defined by a single housing 206. For example, in some embodiments, the fluid end 104 can be modular, and different housing segments can accommodate one or more pumping chambers 208. In any case, one or more pumping chambers 208 are arranged side by side such that the corresponding conduits are positioned adjacent to each other and produce a substantially parallel pumping action. Specifically, in each stroke of the reciprocating element 202, low-pressure fluid is drawn into the pumping chamber 208, and high-pressure fluid is discharged. However, the fluid within the pumping chamber 208 typically contains abrasive materials (i.e., "debris") that can damage the seals in the reciprocating pump 100. Additionally, pressurizing the fluid generates stresses that can concentrate within the pumping chamber.

[0030] As Figure 1B shown, the pumping path and the pumping chamber 208 of the fluid end 104' are formed by conduits that extend through the housing 206 to define openings at the outer surface 210 of the housing 206. More specifically, a first conduit 212 extends longitudinally (e.g., vertically) through the housing 206, while a second conduit 222 extends transversely (e.g., horizontally) through the housing 206. Thus, the first conduit 212 intersects the second conduit 222 to at least partially (and jointly) define the pumping chamber 208. In the prior art fluid end 104 and the prior art fluid end 104', the conduits 212 and 222 are substantially cylindrical, but the diameters of the conduits 212 and 222 can vary throughout the housing 206 such that the conduits 212 and 222 can receive various structures, such as seal assemblies, valves, or their components. For example, although not shown in Figure 1B it, the conduits 212 and / or 222 can support a spring retainer within or near the pumping chamber 208, which, as detailed, allows the valve 241 to control the fluid flow through the inlet section 2126 of the conduit 212.

[0031] Regardless of the diameters of conduits 212 and 222, each of conduits 212 and 222 can include two segments, each segment extending from the pumping chamber 208 to the outer surface 210 of the housing 206 and can also be referred to as a hole. Specifically, the first conduit 212 includes a first segment 2124 and a second segment 2126 opposite the first segment 2124. Similarly, the second conduit 222 includes a third segment 2224 and a fourth segment 2226 opposite the third segment 2224. In the illustrated embodiment, the respective segments of the conduits (e.g., segment 2124 and segment 2126 or segment 2224 and segment 2226) are substantially coaxial, while the respective segments of different conduits are substantially orthogonal. However, in other embodiments, segments 2124, 2126, 2224, and 2226 can be arranged at any desired one or more angles, such as intersecting the pumping chamber 208 at one or more non-right angles.

[0032] In this embodiment, the first conduit 212 defines a fluid path through the fluid end 104. The second segment 2126 is an inlet segment that connects the pumping chamber to the piping system 106 that delivers fluid to the fluid end 104. At the same time, the first segment 2124 is an outlet segment or discharge segment that allows compressed fluid to leave the fluid end 104. Thus, in operation, segments 2126 and 2124 can include valve members 241 and 242 (e.g., check valves) that allow segments 2126 and 2124 to be selectively opened, respectively. The valve member 241 in the second segment 2126 can be fixed in the second segment 2126 by the piping system 106 (see Figure 1A ). At the same time, the valve member 242 in the first segment 2124 can be fixed in the first segment 2124 by the closure assembly 243. In the Figure 1B prior art example shown, the closure assembly 243 includes a closure element 251 (also referred to as a discharge plug) fixed in the first segment 2124 by a retaining assembly 252. The prior art retaining assembly 252 is coupled to the first segment 2124 by threads 2128 defined by the inner wall of the first segment 2124.

[0033] On the other hand, the fourth section 2226 at least partially defines a cylinder for the reciprocating element 202 and / or connects the housing 206 to the cylinder for the reciprocating element 202. For example, in the illustrated embodiment, the housing section 235 is fixed to the fourth section 2226 and houses a filling assembly 236 that is configured to seal the reciprocating element 202 disposed inside the filling assembly 236. In any case, the reciprocating movement of the reciprocating element 202 in or adjacent to the fourth section 2226 (which may be referred to as the reciprocating section) draws fluid into the pumping chamber 208 via the second section 2126 and pumps the fluid out of the pumping chamber 208 via the first section 2124. It is noted that in the illustrated prior art configuration, the filling assembly 236 is held within the housing section 235 by a retaining element 237 that is threadedly coupled to the housing section 235.

[0034] The third section 2224 is an access section that can be opened to access parts disposed within the housing 206 and / or surfaces defined within the housing 206. During operation, the third section 2224 can be closed by a closing assembly 244. In Figure 1B the illustrated prior art example, the closing assembly 244 includes a closing element 254 (also referred to as a suction plug) that is fixed within the third section 2224 by a retaining assembly 256. In particular, the prior art retaining assembly 256 is coupled to the third section 2224 by threads 2228 defined by the inner wall of the third section 2224. However, in some embodiments, the second conduit 222 need not include the third section 2224, and the second conduit 222 can be formed by a single section (the fourth section 2226) that extends from the pumping chamber 208 to the outer surface 210 of the housing 206.

[0035] Generally, in operation, fluid can enter the fluid end 104 (or fluid end 104') via a plurality of openings (such as Figure 1B the opening 216 shown) and leave the fluid end 104 (or fluid end 104') via a plurality of openings (such as Figure 1B the opening 214 shown). In at least some embodiments, the fluid enters the opening 216 via a conduit of the piping system 106, flows through the pumping chamber 208 (due to the reciprocating movement of the reciprocating element 202), and then flows into the channel 108 through the opening 214. However, the piping system 106 and the channel 108 are merely exemplary conduits, and in various embodiments, the fluid end 104 can receive and discharge fluid via any number of pipes and / or conduits along any desired size or shape of path.

[0036] In addition, during operation of the pump 100, a first section 2124 of the first conduit 212, a third section 2224 of the second conduit 222, and a fourth section 2226 of the second conduit 222 may all be “closed” sections. In contrast, a second section 2126 of the first conduit 212 may be an “open” section that permits fluid to flow from the outer surface 210 into the pumping chamber 208. That is, for the purposes of the present application, a “closed” section may prevent or at least substantially prevent direct fluid flow between the pumping chamber 208 and the outer surface 210 of the housing 206, while an “open” section may permit fluid flow between the pumping chamber 208 and the outer surface 210. For clarity, “direct fluid flow” requires flow only along that section such that, for example, fluid flowing from the pumping chamber 208 to the outer surface 210 along the first section 2124 and the passage 108 does not flow directly to the outer surface 210 via the first section 2124.

[0037] Turning now to Figures 2A - 2C , these figures schematically illustrate cross-sectional views of another prior art fluid end to show how a retainer is installed in some fluid ends. Figures 2A - 2C The views of Figures 2A - 2C are illustrated as being taken through the housing of the fluid end of the pump in a plane parallel to the axes 30, 64, and 68 of the bore sections that intersect the housing. For clarity and / or as a result of the cross-sectional views, various components are shown or omitted in Figures 2A - 2C , but such omissions should not be construed as indicating that the fluid ends in the art include or do not include such components. For example, for clarity, a reciprocating element similar to Figure 1A and Figure 1B is not shown in Figure 2A . Similarly, Figure 2B and Figure 2C show a plug 34 that is omitted in Figures 2A - 2C to show certain features of the fluid end. As yet another example, although the retainer 20 is shown in Figures 2A - 2C as being disposed in a retainer groove 22, in Figure 2B and Figure 2C the retainer 20 is shown as supporting a spring 72 that acts on a valve 40 to bias the valve 40 to a closed position against its valve seat 42, but for clarity, Figure 2A components that interact with the retainer 20 are omitted.

[0038] Similar to the prior art fluid end described in connection with Figure 1A and Figure 1B , when the reciprocating element reciprocates in a first direction 26 and an opposite second direction 28 along the central axis 30 of the bore section 32, Figure 2A and Figure 2BFluid end operation. When the reciprocating element reciprocates in the first direction 26, the suction valve 40 moves away from its valve seat 42 towards the retainer 20 (i.e., the suction valve 40 moves away from the closed position). Then the fluid passes over / around the retainer 20 and into the cross holes or pumping chamber of the fluid end. When the reciprocating element reciprocates in the opposite second direction 28, the fluid pushes the discharge valve 48 away from its valve seat 50 and exits the fluid end through the discharge hole section (centered around the axis 68). In the prior art shown, the fluid end is a single integral piece machined from a single casting or forging. However, the fluid end alternatively can have any number of shapes or features, as mentioned in the prior art in connection with Figure 1A and Figure 1B . For example, in other embodiments, the fluid end can be flange - less.

[0039] During the above - mentioned operation, the forces generated by the fluid flow can cause the retainer 20 to rotate about its central axis. Such forces can also urge the retainer 20 to move longitudinally, e.g., in the direction 62 or 66 along the axis 68. Therefore, the retainer 20 must be fixed in place within the fluid end. In the fluid end of this prior art, the closure element 34 (e.g., the suction plug) and the groove 22 extending around a portion of the cross hole provide this fixation. However, the overall extension of the groove 22 around the cross hole is interrupted by the valve cover transition region 78 and the reciprocating hole transition region 70, such that the groove 22 has two opposite sections. That is, the first part and the opposite second part of the groove 22 are not connected; these parts are separated by the transition regions 70 and 78, such that the groove 22 is discontinuous. The transition regions 78 and 80 of this embodiment are typically rounded with valleys. Additionally, the transition regions 78 and 80 are each coplanar with the groove 22, such that the valve cover 34 or the reciprocating element installed in the fluid end can extend into the rotational path defined by the groove 22. However, before the retainer 20 is fixed within the fluid end, the retainer 20 must be installed within the cross hole.

[0040] To install the retainer 20, the retainer 20 is first oriented in a first orientation 11 (e.g., an insertion position or a pre - installation position), as Figure 2B shown. Generally, the retainer 20 and various other parts of the valve assembly (e.g., the valve 40, the valve seat 42, the spring 72, etc.) are installed into the hole section 36, where the valve cover 34 and the reciprocating element are removed or not yet installed into the fluid end. Additionally, the valve 40 and the valve seat 42 are typically installed into the hole section 36 before the retainer 20 is installed in the hole section 36. The spring 72 can be installed with the valve 40 or separately from the valve 40. In summary, after these components are installed within the hole section 36, the spring 72 extends from the valve 40 to the retainer 20. That is, when the retainer 20 is in the orientation 11, the first retainer part 58 of the retainer 20 abuts the reciprocating hole transition region 70 (see Figure 2A) is aligned so that it overlaps with the transition region 70, and the second spring retainer portion 60 is aligned with the valve cover hole transition region 78 (see Figure 2C ) is aligned so that it overlaps with the transition region 78. Thus, the retainer 20 can be moved (e.g., pushed) in the direction 66 to enter / toward the hole section 36 and the valve 40 installed therein to compress the spring 72. This compression continues until the first retainer portion 58 of the retainer 20 abuts the transition region 70 of the fluid end, and the second retainer portion 60 of the retainer 20 abuts the opposite transition region 78 of the fluid end. These abutments prevent further axial movement of the spring retainer 20 in the direction 66.

[0041] As Figures 2A - 2C shown, each of the retainer portions 58 and 60 includes extensions (i.e., wings, lips, etc.) extending from opposite sides of the base portion 57 of the retainer 20. Thus, when the retainer portions 58 and 60 abut the transition regions 70 and 78, the retainer 20 extends through the hole section 36 and can rotate about its central axis at the top of the hole section 36. This causes the retainer portions 58 and 60 of the retainer 20 to move into the grooves 22, which extend around the cross-hole / pumping chamber of the fluid end between the first side edges of the transition regions 70 and 78 and between the second side edges of the transition regions 70 and 78 (the second side edge is opposite to the first side edge). That is, rotating the retainer 20 about its central axis will cause the front edge 84 of the first retainer portion 58 (see Figure 2A ) to move into the first part of the groove 22, while causing the front edge 88 of the second retainer portion 60 (see Figure 2A ) to move into the second part of the groove 22. Thus, rotating the retainer portions 58 and 60 to disengage from the contact with the transition regions 70 and 78 will cause the retainer 20 to move to the engagement or installation position 12, an example of which is shown in Figure 2C .

[0042] As described above, when properly installed, the retainer 20 is fixed within the fluid end, e.g., at its mounting location 12. First, the recess 22 engages the retainer portions 58 and 60 to prevent axial movement of the retainer along the axis 64 / 68 in the direction 62, while the spring 72 acts on the retainer 20 to prevent axial movement of the retainer 20 along the axis 64 / 68 in the direction 66. That is, the spring 72 biases the retainer 20 into engagement with the recess 22 to axially fix the retainer 20 within the fluid end (e.g., within or adjacent to the cross - hole / pumping chamber). Additionally or alternatively, different portions or sections of the retainer 20 may include geometries configured to engage corresponding geometries of the fluid end to axially fix the retainer 20 (e.g., rounded, tapered, etc.). Second, after the retainer 20, valve 40, valve seat 42, and other corresponding parts are installed within the hole section 36, the valve cover 34 is installed into the valve - cover - hole transition region 78 via the access section 34a, thereby providing a rotational stop that prevents the retainer portions 58 and 60 from rotating from one section of the recess 22 to another. That is, once installed, the valve cover 34 limits the rotational range of the retainer 20 to less than 180 degrees and prevents the valve cover 34 from moving back to its first orientation 11. Thus, the retainer 20 cannot move to an orientation that disengages the retainer 20 from the recess 22 and allows removal of the retainer 20 from the fluid end, i.e., orientation 11.

[0043] Now turning to Figure 3 , as described above, this figure schematically shows another existing fluid end 300 to illustrate an exemplary geometry of the cross - hole / pumping chamber of the fluid end 300 that can be improved. In this view, the closure assembly and the retaining assembly have been removed from the fluid end 300 to facilitate its description. The housing or casing 310 of the fluid end 300 includes a plunger or power - end hole 320, which is a hole for a reciprocating member (e.g., a plunger). The plunger hole 320 has an inner wall or surface 322 that defines the plunger hole 320. The plunger hole 320 also has a plunger axis or centerline 324 extending therethrough. The housing 310 includes a valve - cover or access hole 340, which is defined by an inner surface or surface 342 and has a centerline or axis 344. In this embodiment, the valve - cover hole 340 does not include a threaded area for mounting various fluid - end components, but in other embodiments, threads may be formed on the inner surface 342. In this embodiment, the centerline 344 of the valve - cover hole 340 is aligned with the centerline 324 of the plunger hole 320; however, the holes 320 and 340 do not always need to be aligned.

[0044] The fluid end housing 310 also includes an inlet bore 360 defined by an inner wall or surface 362 and having a centerline or axis 364. The housing 310 also includes a discharge bore 380 defined by an inner wall or surface 382 and having a centerline or axis 384. The discharge bore 380 is in fluid communication with the fluid outlet 450, and the centerline 364 of the bore 360 is aligned with the centerline 384 of the discharge bore 380, although these bores 360 and 380 need not always be aligned. The bores 320, 340, 360, and 380 of the housing 310 converge to a common intersection, referred to as the cross bore or cross bore intersection 400. The cross bore intersection 400 (i.e., the pumping chamber) defines an open space within the housing 310. Between each pair of the intersecting adjacent bores 320, 340, 360, and 380 are intersecting corners having a transition region including a surface. Each of these intersections is briefly described in turn below.

[0045] First, the bore 320 and the bore 380 are adjacent to and intersect each other, thereby forming a corner or intersection or overlapping corner 326. The corner 326 includes a transition region 410 between the corners of the bores 320 and 380. Second, the bore 320 and the bore 360 are adjacent to and intersect each other, thereby forming a corner or intersecting corner 328. The corner 328 includes a transition region 412 between the corners of the bores 320 and 360. Generally, due to the internal pressure and the particular fluid being pumped, the surfaces at the intersections of adjacent bores within the fluid end housing are subject to high stress concentrations. In this embodiment, the intersecting corners 326 and 328 (i.e., the corners adjacent to the plunger bore 320) and their respective transition regions 410 and 412 are locations of high stress concentration during operation of the pump.

[0046] Third, the bore 340 and the bore 380 are adjacent to and intersect each other, thereby forming a corner or intersection or overlapping corner 346. The corner 346 includes a transition region 414 between the corners of the bores 340 and 380. Fourth and finally, the bore 340 and the bore 360 are adjacent to and intersect each other, thereby forming a corner or intersecting corner 348. The corner 348 includes a transition region 416 between the corners of the bores 340 and 360. Just as with the intersecting corners 326 and 328, the intersecting corners 346 and 348 (i.e., the corners adjacent to the valve cover bore 340) are locations of high stress concentration during operation of the pump.

[0047] In one embodiment, the inner wall or surface 322 of the plunger hole 320 includes a first portion 330 having a first inner diameter and a second portion 332 having a second inner diameter. The second inner diameter is greater than the first inner diameter. The surface 322 transitions from the first portion 330 to the second portion 332. The second portion 332 includes a curved surface defined by a radius. Similarly, the inner wall or surface 382 of the discharge hole 380 includes a first portion 386 having an inner diameter and a second portion 388 having an inner diameter. The inner diameter of the second portion 388 is greater than the inner diameter of the first portion 386. Additionally, the surface 382 transitions from the first portion 386 to the second portion 388. The second portion 388 also includes a curved surface defined by a radius. In this embodiment, the length of the radius of the curved surface of the second portion 388 of the discharge hole 380 is different from the length of the radius of the curved surface of the second portion 332 of the plunger hole 320. Further, the surfaces 322 and 382 converge with each other at the raised points in the first transition region between the holes 320 and 380.

[0048] To reduce the stress on the surfaces inside the housing 310, particularly at the intersections or overlapping corners between adjacent holes, this embodiment provides a machined surface in the transition region between adjacent holes. If planes are generated using the axes 324, 344, 364, and 384, the profiles of the holes 320, 340, 360, and 380 intersect at approximately tangent points along that plane. For manufacturability, it is beneficial that each intersection point is a slightly raised point relative to the surrounding surface, so that the intersection point can be easily hand-finished or easily sanded with a sanding tool. If the intersection point is recessed relative to the surrounding surface, it is challenging to soften the transition between the two intersecting holes.

[0049] In the illustrated embodiment, the intersection points fall on an intersection line that extends along the cross-hole intersection at all points where the vertical hole intersects the horizontal hole. The intersection points are the locations that experience the highest stress for the cross-hole intersection. By providing substantially tangent surfaces, the stress at these locations is reduced. As the movement is along each intersecting hole transition line away from the central intersection point, the intersection between the intersecting horizontal and vertical holes becomes "less tangent" at locations in the cross-hole intersection 400 where the stress is lower. In this embodiment, the upper transition regions 410 and 414 are formed in a manner similar to the formation of the lower transition regions 412 and 416.

[0050] In this embodiment, the transition regions 410 and 414 are formed to be substantially similar to each other. Additionally, the transition regions 412 and 416 are formed to be substantially similar to each other, but they have a different shape or configuration than the transition regions 410 and 414, as shown. None of the transition regions 410, 412, 414, or 416 have a profile that matches a hemisphere or a partial spherical profile. Instead, a slightly raised feature 411 is formed at the transition region 410 by the surfaces of the adjacent intersecting holes. Each of the other transition regions 412, 414, and 416 may also have a slightly raised feature.

[0051] To fabricate a fluid end having the Figure 3 geometric structure shown, a first hole is machined in the fluid end housing first. In one embodiment, the first hole is formed such that it has an inner surface that transitions from a first portion having a first inner diameter to a second portion having a second inner diameter. The second inner diameter is greater than the first inner diameter. Next, a second hole is machined in the housing. Similar to the first hole, the second hole is formed with an inner surface that transitions from a third portion having a third inner diameter to a fourth portion having a fourth inner diameter, and the fourth inner diameter is greater than the third inner diameter. When the first hole and the second hole are machined, the fourth portion of the second inner surface intersects the second portion of the first inner surface at a first intersecting corner. At this first intersecting corner, the fourth portion and the second portion together form a slightly raised feature.

[0052] In one embodiment of the present invention, approximately 90% of the manufacturing steps for forming the first hole and the second hole are completed by machining processes. Then, the remaining polishing for reducing the raised points at the intersections of adjacent holes is achieved by hand finishing. In one embodiment, the operator hand finishes the intersecting corners between other adjacent intersecting holes through a third hole. In another embodiment, the intersecting area to be hand finished is accessed by passing through one of the adjacent intersecting holes. In any case, this embodiment provides that the inner surfaces of the holes have a geometric structure that reduces the stress on the fluid end 300 caused by fluid pressure. In particular, Figure 3 the geometric structure attempts to minimize the operating stress in the lower quadrant (or hemisphere) of the cross-hole intersection 400 and improve the fatigue life of the fluid end 300. The hemispherical transition surface tends to reduce the stress concentration at the cross-hole intersection 400 by smoothing the geometric structure of the inlet hole 360 and improving the load distribution around the cross-hole intersection 400.

[0053] Unfortunately, the hand finishing process for forming the fluid end 300 can be cumbersome and time-consuming and is prone to human error. Therefore, increasing the manufacturing processes that can be achieved by machining processes rather than manual processes can improve the manufacture of the fluid end. Additionally, the geometric structure of the fluid end 300 may not fix the valve holder therein to the desired degree. For example, while some existing fluid ends (e.g.,Figures 2A - 2C ) allows the valve retainer to be securely mounted in the fluid end. Other fluid ends (e.g., Figure 3 ) change the geometry of the pumping chamber to reduce stress concentrations, but pursuing the advantages of these existing fluid ends has proven problematic. More specifically, generally, in order to securely hold the valve retainer in the fluid end recess, when preventing the valve retainer from rotating by interfering with the valve cover, the valve retainer should be circumferentially engaged in its recess by at least 50%. This is typically achieved by balancing the arc length of the recess with the length of the valve cover extending into the cross-hole. However, when changing the geometry of the cross-hole to reduce stress, the available arc length of the recess can be reduced to achieve 50% circumferential engagement. In practice, the only way to typically compensate for the reduction in circumferential engagement caused by this change in the geometry of the cross-hole is to extend the valve cover further into the cross-hole. This is undesirable because it is difficult to install and service the valve cover in this position, and because the valve cover extending substantially into the cross-hole may potentially impact the reciprocating element during the forward stroke. In fact, contact between the valve cover and the reciprocating element is highly undesirable because it can damage parts of the pump and / or increase wear. Alternatively, a valve cover that extends substantially into the cross-hole can shorten the maximum stroke length of the reciprocating element, which will limit the efficiency of the pump and / or limit the configurations / components / applications for which the fluid end can be used. For example, the fluid end may only be usable with a limited number of power ends, only for certain applications that reach a threshold pressure, etc.

[0054] The cross-hole geometry presented in this application addresses these problems, and Figure 4 an exemplary cross-hole geometry is shown in Figure 4 a top cross-sectional view of fluid end 500. Fluid end 500 includes a first hole 502 (e.g., a plunger hole, a first horizontal hole) extending along a first axis 506 (e.g., a horizontal axis) and a second hole 504 (e.g., a suction hole, an access hole, a second horizontal hole). Fluid end 500 also includes a hole (not shown) extending along a second axis 508 (e.g., a vertical axis). These holes 502, 504 intersect at cross-hole 510 of fluid end 500. Valve retainer 512 is fixed within cross-hole 510.

[0055] Each of the holes 502 and 504 includes a first main cylindrical portion 514, and the cross-sectional geometry of the holes 502 and 504 remains substantially the same along the first main cylindrical portion 514 (e.g., having the same circular shape). Additionally, each of the holes 502 and 504 includes a first tapered portion 516 extending from the first main cylindrical portion 514 toward the cross-hole 510. The cross-sectional area of the holes 502 and 504 increases toward the cross-hole 510 along the first tapered portion 516, and the first tapered portion 516 provides a transition from the holes 502 and 504 to the cross-hole 510 to reduce stress concentration. In particular, the increase in the cross-sectional area of the holes 502 and 504 provided by the first tapered portion 516 reduces the geometric discontinuity (e.g., no sharp corners) at the intersection of the holes 502 and 504 with other holes (not shown), such as vertical holes, and / or the cross-hole 510. Thus, the first tapered portion 516 can reduce wear of the fluid end 500.

[0056] Furthermore, each of the holes 502 and 504 includes a second tapered portion 518 extending from the first tapered portion 516 toward the cross-hole 510. The cross-sectional area of the holes 502 and 504 decreases toward the cross-hole 510 along the second tapered portion 518. Each second tapered portion 518 intersects a hole extending along the second axis 508 (i.e., each tapered portion 518 independently intersects the same vertical hole). Specifically, the hole extending along the second axis 508 includes a second main cylindrical portion 520 that terminates at the cross-hole 510 to form a shoulder 522 and define a groove 526. The second main cylindrical portions 520 and the second tapered portions 518 of the holes 502 and 504 converge with each other to form a peak 524 of the shoulder 522, and the peak 524 extends inwardly around the second main cylindrical portion 520 toward the cross-hole 510 (e.g., at least one vector component of the extension extends substantially transversely to the first axis 506). The second main cylindrical portion 520 and the adjacent peak 524 together form an M-shaped configuration. In some embodiments, the M-shaped configuration is symmetric (e.g., the first tapered portions 516 have substantially the same orientation, the second tapered portions 518 have substantially the same orientation, and the adjacent peaks 524 have substantially the same geometry). In alternative embodiments, the M-shaped configuration is asymmetric (e.g., the first tapered portions 516 have different orientations, the second tapered portions 518 have different orientations, and the adjacent peaks 524 have different geometries). That is, for clarity, even though the tapered portions 518 are labeled with the same reference numerals, the tapered portions need not be the same.

[0057] In the illustrated embodiment, each of the first tapered portion 516 and the second tapered portion 518 extends arcuately. For example, to provide a sufficiently smooth transition that reduces stress concentration, the first tapered portion 516 may have a first radius that is greater than the second radius of the second tapered portion 518. However, in alternative embodiments, the first tapered portion 516 and the second tapered portion 518 may have radii of any suitable size, such as similar radii. Alternatively, the tapered portions 516 and 518 need not have a single radius and / or need not be arcuate. That is, the tapered portions 516 and 518 may be formed of a compound radius, formed of linear and arcuate shapes, or formed of any other desired geometry, and again, the tapered portions 518 need not be the same in shape, size, etc.

[0058] The groove 526 defined by the shoulder 522 is configured to receive the valve holder 512 so as to fix the valve holder 512 within the fluid end 500, for example, at least partially within the cross-bore 510. For example, when the valve holder 512 is in the installed configuration within the fluid end 500, the shoulder 522 including the peak 524 may capture the holder portion 528 of the valve holder 512 to prevent rotation of the valve holder 512 and maintain the engagement of the valve holder 512 with the shoulder 522.

[0059] Figure 5 The fluid end 500 is shown with the valve holder 512 in the installed configuration 550. Accordingly, the holder portion 528 of the valve holder 512 engages the shoulder 522 including the peak 524. It can be seen that the second tapered portion 518 reduces the cross-sectional areas of the bores 502 and 504 and increases the arc length of the shoulder 522, thereby increasing the available surface area for engaging the valve holder 512 and preventing axial movement of the valve holder 512. That is, because the second tapered portion 518 provides the inwardly extending peak 524, the shoulder 522 can better surround the holder portion 528 to increase circumferential engagement. In turn, this ensures that the holder portion 528 remains engaged with the shoulder 522 and cannot slide or otherwise move past the shoulder 522. For example, by extending inwardly toward the cross-bore 510, the second tapered portion 518 can compensate for the first tapered portion 516, which extends outwardly away from the cross-bore 510 and would otherwise reduce the available surface area for engaging the holder portion 528. For example, the peak 524 formed by the second tapered portion 518 and the second main cylindrical portion 520 may extend inwardly beyond the first main cylindrical portion 514 of the bores 502 and 504 to achieve the desired engagement of the valve holder 512.

[0060] For example, about 55% or more, about 65% or more, about 75% or more, or even about 85% or more of the outer periphery of the valve retainer 512 can be engaged in the groove 526 of the cross-hole geometry described in the present invention. For example, one retainer portion 528 spans an arc of about 67.5 degrees, and about 55% or more, about 65% or more, about 75% or more, or even about 85% or more of this arc can be engaged by the corresponding shoulder 522 described in the present invention.

[0061] Implementing the second tapered portion 518 enables the geometry of the first tapered portion 516 to be established more flexibly. For example, the extension length and / or the degree of extension of the first tapered portion 516 can be increased to provide a sufficiently smooth transition, thereby reducing stress concentration, and the second tapered portion 518 can be manufactured accordingly to extend inwardly and provide shoulders 522 and peaks 524 that are oriented to achieve the desired engagement of the valve retainer 512. Thus, the first tapered portion 516 can be manufactured in a suitable manner to reduce stress concentration with limited hand finishing without reducing the stability of the valve retainer 512 in the fluid end 500.

[0062] Figure 6 is a bottom cross-sectional view of the fluid end 600. The fluid end 600 includes a first hole 602 (e.g., a plunger hole, a first horizontal hole) extending along a first axis 606 (e.g., a horizontal axis) and a second hole 604 (e.g., a valve cap hole, a second horizontal hole). The fluid end 600 further includes a third hole 607 extending along a second axis 608 (e.g., a vertical axis). These holes 602, 604, and 607 intersect at the cross-hole 610 of the fluid end 600.

[0063] Each of the holes 602 and 604 includes a first main cylindrical portion 614, and the cross-sectional geometry of the holes 602 and 604 remains substantially the same along the first main cylindrical portion 614. Additionally, each of the holes 602 and 604 includes a first tapered portion 616 extending from the first main cylindrical portion 614 toward the cross-hole 610 to increase the cross-sectional area of the holes 602 and 604 along the first tapered portion 616 toward the cross-hole 610, thereby providing a transition from the holes 602 and 604 to the cross-hole 610 to reduce stress concentration. Further, each of the holes 602 and 604 includes a second tapered portion 618 extending from the first tapered portion 616 toward the cross-hole 610 to decrease the cross-sectional area of the holes 602 and 604 along the second tapered portion 618 toward the cross-hole 610. The third hole 607 includes a second main cylindrical portion 620 that terminates at the cross-hole 610 to form a shoulder (not shown) that is configured to capture a valve retainer (not shown) disposed within the cross-hole 610. The second main cylindrical portion 620 and the second tapered portions 618 of the holes 602, 604 converge with each other to form a peak portion 624 that extends inwardly around the second main cylindrical portion 620 toward the cross-hole 610, thereby forming an M-shaped configuration.

[0064] In this embodiment, the first tapered portion 616 extends linearly, while the second tapered portion 618 extends in an arcuate shape. For example, the first tapered portion 616 can form a sufficient angle 626 with the corresponding first main cylindrical portion 614 (e.g., with the first axis 606) to expand the cross-sectional area of the holes 602 and 604, thereby providing a smooth transition to reduce stress concentration. Additionally, the second tapered portion 618 extends inwardly to increase the arc length of the shoulder, thereby increasing the available surface area for engagement with the valve retainer (e.g., to compensate for the extension of the first tapered portion 616).

[0065] Figure 7is a perspective cross-sectional view of the fluid end 600, showing the intersection of the holes 602, 604, and 607. Specifically, the holes 602 and 604 intersect with a third hole 607 to form corresponding corners 650, and the second tapered portions 618 of the holes 602 and 604 meet the second major cylindrical portion 620 of the third hole 607 to form a peak 624. The tapered portions 616 and 618 form a transition region that reduces stress concentration without the need for manual finishing. For example, the tapered portions 616 and 618 can be manufactured by machining processes, such as processes that do not produce raised features that are subsequently reduced by manual finishing. Thus, the manufacturability of the fluid end 600 is improved. A shoulder 622 having a peak 624 provided by the intersection of the holes 602 and 604 with the third hole 607 defines a groove 652 configured to receive a valve retainer (e.g., valve retainer 512), and the peak 624 provides a sufficient surface area for engaging the valve retainer to secure the valve retainer in the groove 652.

[0066] Figure 8 is a side cross-sectional view of a fluid end 700 (e.g., fluid end 500, fluid end 600) that has a first hole 702 (e.g., a plunger hole, a first horizontal hole) and a second hole 704 (e.g., a valve cap hole, a second horizontal hole) extending along a first axis 706 (e.g., a horizontal axis), and a third hole 707 and a fourth hole 709 extending along a second axis 708 (e.g., a vertical axis). The holes 702, 704, 707, and 709 intersect at an intersection hole 710 of the fluid end 700.

[0067] Each of the holes 702 and 704 includes a first major cylindrical portion 714, a first tapered portion 716, and a second tapered portion 718. The first tapered portion 716 extends from the first major cylindrical portion 714 toward the intersection hole 710 to increase the cross-sectional area of the holes 702 and 704 along the first tapered portion 716 toward the intersection hole 710. The second tapered portion 718 extends from the first tapered portion 716 toward the intersection hole 710 to decrease the cross-sectional area of the holes 702 and 704 along the second tapered portion 718 toward the intersection hole 710. The third hole 707 includes a second major cylindrical portion 720 that terminates at the intersection hole 710 to form a shoulder 722 configured to capture a valve retainer (not shown) disposed within the intersection hole 710. The second major cylindrical portion 720 and the second tapered portions 718 of the holes 702 and 704 converge with each other to form a peak 724 that extends inwardly around the second major cylindrical portion 720 toward the intersection hole 710, thereby forming an M-shaped configuration.

[0068] Holes 702 and 704 intersect with a third hole 707 to form a corner 740. However, the first tapered portion 716 provides a smoother transition from holes 702, 704 to the intersecting hole 710 at the corner 740. For example, the first tapered portion 716 forms a smoother / more rounded corner 740 at the location where holes 702, 704 intersect with the third hole 707, rather than a sharp edge, thus blending holes 702, 704 with the third hole 707. In some embodiments, the second tapered portion 718 extends from a portion of the first tapered portion 716, rather than from the entirety of the first tapered portion 716. As an example, the second tapered portion 718 can extend from a specific portion of the outer periphery of the first tapered portion 716 to form a shoulder 722 that captures the retainer portion of the valve retainer in the installed configuration of the valve retainer, and the second tapered portion 718 does not extend from the remaining portion of the first tapered portion 716 that does not require a shoulder to capture the valve retainer. Thus, the second tapered portion 718 is specifically implemented to provide a shoulder 722 that aligns with the retainer portion in the installed configuration of the valve retainer. For example, selectively forming the second tapered portion 718 in this manner provides sufficient clearance within the intersecting hole 710 (e.g., reduces the volume occupied by the shoulder 722) to enable insertion of the valve retainer into and removal of the valve retainer from the intersecting hole 710, while also enabling the valve retainer to achieve the desired fixation.

[0069] Figure 9 A top view of the fluid end 750 is shown, showing the path 752 of a tool 754 for forming an M-shaped configuration within the fluid end 750. The tool 754 includes a shaft 756 attached to a blade 758. The shaft 756 is configured to rotate the blade 758 to provide a cutting action. The fluid end 750 includes a first hole 762 (e.g., valve cover hole, first horizontal hole) and a second hole 764 (e.g., plunger hole, second horizontal hole) that extend along a first axis 766. The fluid end 750 also includes a hole (not shown) that extends along a second axis 768 (e.g., vertical axis). These holes 762 and 764 intersect at an intersecting hole 770 of the fluid end 750.

[0070] The first hole 762 includes a main cylindrical portion 772 that initially extends to the crossover hole 770, and a tool 754 is used to form a tapered portion that extends from the main cylindrical portion 720 to the crossover hole 770. Generally, the tool 754 is moved along a path 752 as follows: along the central axis 776 of the first hole 762 toward the crossover hole 770, the tool 754 is moved through the first hole 762, and the blade 758 is moved against the wall of the first hole 762 about the central axis 776 to remove material from the wall, thereby conditioning the main cylindrical portion 772 and forming the profile of the tapered portion. In particular, to form the first tapered portion 774, at a first portion 778 of the path 752, the rotation of the tool 754 about the central axis 776 increases in size toward the crossover hole 770. That is, the tool 754 moves in an increasing helical motion, thereby increasing the amount of material removed and increasing the cross-sectional area of the first hole 762 toward the crossover hole 770. In the illustrated embodiment, the first tapered portion 774 extends generally linearly. To this end, the rotation of the tool 754 about the central axis 776 can increase in stable increments (e.g., the circumference / diameter of the rotation increases linearly toward the crossover hole 770). After the first tapered portion 774 has been formed, the tool 754 is moved via a second portion 782 of the path 752 to form a second tapered portion 780 that extends from the first tapered portion 774 by decreasing the size of the rotation of the tool 754 about the central axis 776 toward the crossover hole 770. That is, the tool 754 moves in a decreasing helical motion, thereby decreasing the amount of material removed and decreasing the cross-sectional area of the first hole 762 toward the crossover hole 770. For example, the second tapered portion 780 extends arcuately, and the rotation of the tool 754 about the central axis 776 can decrease in varying increments (e.g., the circumference / diameter of the rotation decreases exponentially or accelerates toward the crossover hole 770).

[0071] The tool 754 can be moved in a similar manner to form the tapered portion of the second hole 764. In some embodiments, the tool 754 is moved from the crossover hole 770 through the second hole 764 (e.g., and rotated about the central axis of the second hole 764) to form the tapered portion of the second hole 764. In additional or alternative embodiments, the tool 754 moves through the second hole 764 (e.g., the main cylindrical portion of the second hole 764) toward the crossover hole 770 (e.g., and rotated about the central axis of the second hole 764) to form the tapered portion of the second hole 764.

[0072] In any case, this movement of tool 754 along path 752 forms tapered portions 774 and 780 that provide a geometry with reduced stress concentration and increased engagement with the valve retainer. In fact, tool 754 can be used to form tapered portions 774 and 780 without the need to supplement the removal of material from the first hole 762 with hand finishing. That is, tool 754 alone can adequately form the desired geometry of fluid end 750, which mixes holes 762 and 764 with corresponding intersecting holes, thereby increasing the ease of manufacture of fluid end 750.

[0073] Figure 10 and Figure 11 are cross-sectional views to show different cross-hole geometries. In particular, Figure 10 is a side cross-sectional view of a prior art fluid end 802 showing holes 804 and 806 (e.g., horizontal holes) intersecting holes 808 and 810 (e.g., vertical holes). Fluid end 802 does not include the cross-hole geometry disclosed in the present invention (e.g., holes 804 and 806 do not include tapered portions). Thus, holes 804 and 806 intersect holes 808 and 810 to form sharp corners 812. Sharp corners 812 are subject to increased stress concentration, thereby increasing wear of fluid end 802.

[0074] Figure 11 is a side cross-sectional view of a fluid end 852 showing holes 854 and 856 (e.g., horizontal holes) intersecting holes 858 and 860 (e.g., vertical holes). Fluid end 852 includes the cross-hole geometry disclosed in the present invention (e.g., holes 854 and 856 include tapered portions). Thus, holes 854 and 856 intersect holes 858 and 860 to form relatively smooth corners 862, thereby blending holes 854 and 856 with holes 858 and 860. Smoothed corners 862 reduce stress concentration, thereby reducing wear of fluid end 852.

[0075] Figure 12 is a flow chart of a method 900 for manufacturing a fluid end, which is, for example, any one of the fluid ends 500, 600, 700, 750, 852 discussed in the present invention. It should be noted that method 900 can be performed differently than depicted. By way of example, additional operations can be performed, and / or any of the described operations can be performed differently, in a different order, and / or not performed. In some embodiments, method 900 can be performed via a machining process without the need to utilize hand finishing or other manual processes.

[0076] At block 902, a main cylindrical portion of a hole (e.g., a horizontal hole) is formed in the fluid end. For example, material is removed from the hole to form the main cylindrical portion along which the cross-sectional area of the hole remains substantially the same. The hole extends to intersect one or more other holes of the fluid end at an intersection hole of the fluid end. The main cylindrical portion extends to the intersection hole.

[0077] At block 904, a first tapered portion of the hole is formed to increase the cross-sectional area of the hole toward the intersection hole. For example, a tool having a blade can be inserted into the main cylindrical portion of the hole and moved toward the intersection hole, and the blade can be rotated about a central axis extending through the hole so that the blade contacts the wall of the hole, thereby removing material and conditioning the profile of the main cylindrical portion as the tool moves toward the intersection hole. The rotation of the blade about the central axis increases in size as the blade moves toward the intersection hole, thereby increasing the cross-sectional area of the hole along the first tapered portion toward the intersection hole. The first tapered portion of the hole smooths the transition of the hole to the intersection hole, thereby reducing stress concentration where the holes intersect (e.g., to form an intersecting blend corner).

[0078] At block 906, a second tapered portion of the hole is formed to decrease the cross-sectional area of the hole toward the intersection hole. As an example, a tool having a blade can move from the first tapered portion toward the intersection hole, and the rotation of the blade about the central axis can decrease in size as the blade moves toward the intersection hole, thereby decreasing the cross-sectional area of the hole along the second tapered portion toward the intersection hole. The second tapered portion of the hole forms a peak with the intersecting hole to provide a shoulder having an increased arc length. Thus, a surface area large enough for engaging a valve retainer is also provided.

[0079] After the geometry of the hole in the fluid end has been formed, a valve retainer can be installed in the fluid end. For example, the valve retainer can be placed to engage a shoulder (e.g., a peak) formed by method 900. The increased arc length of the shoulder formed by the second tapered portion of the hole can improve the stability of the valve retainer in the fluid end so as to, for example, prevent or inhibit rotation of the valve retainer.

[0080] Although the embodiments disclosed in the present invention mainly discuss holes having two tapered portions to form an M-shaped configuration, in additional or alternative embodiments, the hole can have a different number of tapered portions to form different shaped configurations. As an example, the hole can have more than two tapered portions, such as multiple tapered portions that increase the cross-sectional area of the hole toward the intersection hole and / or multiple tapered portions that decrease the cross-sectional area of the hole toward the intersection hole. As another example, the hole can have a single tapered portion, such as a tapered portion that decreases the cross-sectional area of the hole (e.g., to provide a peak and form a shoulder having an increased arc length), without a tapered portion that increases the cross-sectional area of the hole. Such embodiments of the hole can still provide at least some of the benefits described in the present invention.

[0081] Although the present invention has been shown and described in detail with reference to specific embodiments thereof, the present invention is not limited to the details shown, since it will be apparent that various modifications and structural changes may be made without departing from the scope of the present invention and within the scope and bounds of equivalents of the claims. In addition, various features from one embodiment may be incorporated into another embodiment. In fact, the technology described in the present invention can be applied to any fluid end block having at least two intersecting holes. Accordingly, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the disclosure set forth in the appended claims.

[0082] Similarly, the present invention is intended to cover modifications and variations of the present invention that fall within the scope of the appended claims and their equivalents. For example, it should be understood that terms such as "left", "right", "top", "bottom", "front", "rear", "side", "height", "length", "width", "upper", "lower", "inner", "outer", "inside", "outside" used in the present invention only describe reference points and do not limit the present invention to any particular orientation or configuration. In addition, the term "exemplary" is used in the present invention to describe an example or illustration. Any embodiment described as an example in the present invention should not be construed as a preferred or advantageous embodiment, but rather as an example or illustration of a possible embodiment of the present invention.

[0083] Finally, when used in the present invention, the term "comprising" and its derivatives (such as "including", etc.) should not be understood in an exclusive sense, i.e., these terms should not be construed as precluding the possibility that the described and defined content may include additional elements, steps, etc. At the same time, when used in the present invention, the term "approximate" and its like terms (such as "about", etc.) should be understood to indicate a value that is very close to those values accompanied by the foregoing terms. That is, a deviation within a reasonable limit from the exact value should be accepted, since those skilled in the art will understand that such deviations of the indicated values are inevitable due to measurement inaccuracies, etc. This also applies to the terms "about" and "substantially".

Claims

1. A fluid end, comprising: A first hole extending through the fluid end, the first hole including a first main cylindrical portion and a tapered portion; A second hole extending through the fluid end, the second hole including a second main cylindrical portion; And A cross hole where the first hole intersects the second hole, wherein the second main cylindrical portion of the second hole terminates at the cross hole to form a shoulder in the cross hole, and the tapered portion of the first hole and the second main cylindrical portion of the second hole jointly define a peak extending inward to the cross hole.

2. The fluid end according to claim 1, further comprising a valve retainer configured to be disposed in the cross hole and engage with the shoulder formed by the second main cylindrical portion of the second hole.

3. The fluid end according to claim 2, wherein, The valve retainer is further configured to engage with the peak jointly defined by the tapered portion of the first hole and the second main cylindrical portion of the second hole.

4. The fluid end according to claim 1, wherein The first hole includes an additional tapered portion extending between the first main cylindrical portion and the tapered portion, and the additional tapered portion increases the cross-sectional area of the first hole along the additional tapered portion toward the cross hole.

5. The fluid end according to claim 4, wherein, The additional tapered portion of the first hole extends linearly or arcuately.

6. The fluid end according to claim 4, wherein Each of the tapered portion and the additional tapered portion of the first hole extends arcuately, and a first radius of the additional tapered portion is greater than a second radius of the tapered portion.

7. The fluid end according to claim 1 further comprises a third hole, wherein, The third hole includes an additional tapered portion, and the additional tapered portion of the third hole and the second main cylindrical portion of the second hole jointly define an additional peak extending inward to the cross hole, such that the peak, the second main cylindrical portion, and the additional peak jointly form an M-shaped configuration.

8. The fluid end according to claim 1, wherein, The peak jointly defined by the tapered portion of the first hole and the second main cylindrical portion of the second hole is a part of the shoulder in the cross hole.

9. A method for manufacturing a fluid end, the method comprising: Forming a first hole of the fluid end, wherein the first hole includes a main cylindrical portion; and Forming a second hole of the fluid end to intersect the first hole at a cross hole of the fluid end, wherein forming the second hole includes forming a tapered portion of the second hole, and the tapered portion decreases the cross-sectional area of the second hole along the tapered portion toward the cross hole, and the tapered portion and the main cylindrical portion jointly define a peak extending inward to the cross hole.

10. The method according to claim 9, wherein: Forming the second hole includes forming an additional tapered portion of the second hole, and the additional tapered portion increases the cross-sectional area of the second hole along the additional tapered portion toward the tapered portion and the cross hole of the fluid end.

11. The method according to claim 10, wherein: Forming the second hole includes forming an additional main cylindrical portion extending toward the tapered portion of the second hole.

12. The method according to claim 9, wherein Forming the tapered portion of the second hole includes moving a tool with a blade along a central axis of the second hole between the second hole and the cross hole, and rotating the tool around the central axis to remove material from the second hole.

13. The method according to claim 12, wherein, Moving the tool with the blade along the central axis between the second hole and the cross hole includes moving the tool with the blade from the second hole towards the cross hole.

14. The method according to claim 9, wherein The main cylindrical portion of the first hole terminates at the cross hole to provide a shoulder defining a groove, and the method further includes setting a valve holder in the groove to engage the valve holder with the peak portion jointly defined by the tapered portion and the main cylindrical portion.

15. A fluid end, comprising: A first hole, the first hole including a cylindrical portion; And A second hole, the second hole extending through the fluid end and intersecting the first hole at a cross hole, wherein the first hole includes a first tapered portion that increases the cross-sectional area of the second hole along the first tapered portion towards the cross hole, the first hole includes a second tapered portion that decreases the cross-sectional area of the second hole along the second tapered portion towards the cross hole, and the second tapered portion abuts the cylindrical portion of the first hole.

16. The fluid end according to claim 15, wherein The second tapered portion of the second hole abuts the cylindrical portion of the first hole to form a peak portion extending inwards into the cross hole.

17. The fluid end according to claim 16, further comprising: A groove, the groove being formed at least in part by the cylindrical portion of the first hole and the peak portion formed by the abutment between the second tapered portion of the second hole and the cylindrical portion of the first hole; and A valve holder, the valve holder being set in the groove.

18. The fluid end according to claim 16, wherein The second hole includes an additional cylindrical portion extending along the axis, and the peak portion extends transversely to the axis.

19. The fluid end according to claim 18, wherein The peak portion extends inwards beyond the additional cylindrical portion.

20. The fluid end according to claim 15, wherein The second tapered portion extends arcuately.

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