Isolation Gap in Fluid End Dynamic Body

The present invention is directed to a fluid end. The fluid end comprises a dynamic body having a first end and a second end. The dynamic body has at least one internal through-bore extending about a central, longitudinal axis from a first opening at the first end to a second opening at the second end. The dynamic body comprises a first circumferential isolation ring formed at the first end of the dynamic body about the first opening and is concentric about the central, longitudinal axis of the at least one internal through-bore. The fluid end also comprises a static body attached to the dynamic body at the first end.

In another aspect the present invention is directed to a fluid end. The fluid end comprises a static body having five bores and a dynamic body. The dynamic body has a first surface and a second surface. The dynamic body is attached to the static body at the first surface. The dynamic body has five through-bores extending from the first surface to the second surface, in which the dynamic body is attached to the static body such that each of the five through-bores is aligned with a selected one of the five bores of the static body about a central axis.

Each of the five through-bores defines a first section, a second section, and an intermediate section. The first section is at a first end of the through-bore and concentric about the central axis. The second section is at a second end of the through-bore and concentric about the central axis. The intermediate section is disposed between the first section and the second section and concentric about the central axis. The intermediate section meets the first section at a first annular shoulder and the second section at a second annular shoulder. The first section is circumscribed by a first isolation ring formed in the first surface of the dynamic body. The first isolation ring is bounded on an inside surface by the through-bore and on an outside surface by a first annular isolation gap formed in the first surface.

In another aspect, the invention is directed to a dynamic body section for use with a fluid end in a hydraulic fracturing pump. The dynamic body section comprises a body, a first isolation ring, and a second isolation ring. The body has a first side and a second side and at least one through-bore interconnecting the first side and the second side. The at least one through-bore extends about a central axis. The first isolation ring is disposed on the first side of the dynamic body section and concentric about the central axis. The second isolation ring is disposed on the second side of the dynamic body section and concentric about the central axis.

A high-pressure pumpis shown in. The high-pressure pumpcomprises a power end, a multi-piece fluid end, a plurality of first stay rods, a plurality of spacers, a plurality of fluid end fasteners, and a plurality of pony rod clamps. The multi-piece fluid endshown in, comprises a fluid end body, a plurality of flow control systems, a plurality of plunger systems, a plurality of discharge manifolds, and a plurality of suction manifolds. The fluid end body, shown in, comprises a static section, a dynamic section, a plurality of second stay rods, and a plurality of body fasteners. The dynamic section, shown in, comprises a dynamic body, a plurality of plunger system wear rings, a plurality of plunger system wear ring seals, a plurality of plunger system seals, a plurality of flow control system wear rings, and a plurality of flow control system wear ring seals.

The dynamic body, shown in, has the general shape of a rectangular prism. The dynamic bodycomprises opposing frontand backsurfaces, opposing topand bottomsurfaces, and opposing leftand rightsurfaces. The dynamic bodyfurther comprises a plurality of flow bores. Each flow boreis a through bore connecting the frontand backsurfaces. The bore axis of each flow boreis parallel to the transverse axis of the dynamic body. In this embodiment there are five flow boresevenly spaced between the leftand rightsurfaces and centered between the topand bottomsurfaces.

Referring now to, beginning at the front surfaceof the dynamic bodyand moving along the bore axis of the flow boreto the back surface, the flow borecomprises a flow control system wear ring section, a flow control system wear ring shoulder, a flow control system section, a plunger section, a plunger system shoulder, a plunger system section, a plunger system wear ring shoulder, and a plunger system wear ring section. The flow control system wear ring sectioncomprises a seal grooveand the plunger system wear ring sectioncomprises a seal groove.

The flow control system wear ring sectionis tapered, as can be seen in. The largest diameter of the taper is at the front surfaceand the smallest diameter is at the flow control system wear ring shoulder. The taper is complementary to the taper of the outer surface of the flow control system wear ring, as shown in.

Seal groovecomprises two side wallsconnected by a base. Each side wallis perpendicular to the bore axis of the flow boreand extends from the tapered surface of the flow control system wear ring sectionaway from the bore axis of the flow bore. The baseis flat, that is parallel to the bore axis of the flow bore. The seal grooveis located from the front surfaceof the dynamic bodyalong the bore axis of the flow boreapproximately one-third of the total distance between the front surfaceand the flow control system wear ring shoulder.

The flow control system wear ring shoulderis formed by the reduction in diameter of the flow borebetween the flow control system wear ring sectionand the flow control system section. The flow control system wear ring shoulderis perpendicular to the bore axis of the flow bore.

Referring now to, the flow control system section, comprises a straight portion, that is the bore wall is parallel to the bore axis of the flow bore, and a tapered portion. As can be seen inthe flow control system sectionis complementary to the particular components of the flow control systemthat are inserted within the flow control system section.

The plunger sectionis also straight and provides a volume for the fluid to enter on the suction stroke of the plunger systemand to exit from as the plunger systemapplies force, generating fluid pressure, on the pressure stroke, as shown in.

The plunger system shoulderis formed by the increase in diameter of the flow borebetween the plunger sectionand plunger system section. The plunger system shoulderis perpendicular to the bore axis of the flow bore.

The plunger system sectionis also straight and complementary to the particular component of the plunger systemthat is inserted within the plunger system section, as shown in.

The plunger system wear ring shoulderis formed by the increase in diameter of the flow borebetween the plunger system sectionand the plunger system wear ring section. The plunger system wear ring shoulderis perpendicular to the bore axis of the flow bore.

The plunger system wear ring sectionis tapered, as can be seen in. The largest diameter of the taper is at the back surfaceand the smallest diameter is at the plunger system wear ring shoulder. The taper is complementary to the taper of the outer surface of the plunger system wear ring, as shown in.

Seal groovecomprises two side wallsconnected by a base. Each side wallis perpendicular to the bore axis of the flow boreand extends from the tapered surface of the plunger system wear ring sectionaway from the bore axis of the flow bore. The baseis flat, that is parallel to the bore axis of the flow bore. The seal grooveis located from the back surfaceof the dynamic bodyalong the bore axis of the flow boreapproximately one-half of the total distance between the back surfaceand the plunger system wear ring shoulder.

Referring now to, the top surfaceand bottom surfaceof the dynamic bodyeach comprise a longitudinal cutout. The longitudinal cutoutsare identical but mirrored about the transverse axis of the dynamic body, for each surfaceand. The features and components of the longitudinal cutoutof the top surfacewill be described with the understanding that every feature and component is present in the longitudinal cutoutof the bottom surfaceand is labeled with the same reference numbers in the figures.

The longitudinal cutoutextends from the left surfaceto the right surfaceand comprises a front wall, back wall, and base. The longitudinal cutoutfurther comprises a plurality of support websthat extend between, and connect, the front walland back wallof the longitudinal cutout. The support websalso extend vertically from the base. There are five support websin this embodiment which are aligned with the bore axes of the flow boreson a one-to-one basis. The formation of the longitudinal cutoutcreates a front flangehaving a front surfacecoincident with the front surfaceof the dynamic bodyand a back surfacecoincident with the front wallof the longitudinal cutout. In like manner, a back flangeis created having a front surfacecoincident with the back wallof the longitudinal cutoutand a back surfacecoincident with the back surfaceof the dynamic body.

The front surfaceof the dynamic bodycomprises a plurality of second stay rod bores. Each second stay rod boreis a threaded blind bore configured to receive a first threaded endof a second stay rod. In this embodiment the plurality of second stay rod boresare located in five groups of four with each group centered on a bore axis of one of the plurality of flow boreson a one-to-one basis. As can be seen in, each group of four second stay rod boresis distributed symmetrically about the longitudinal and vertical axes centered on each bore axis of the paired flow bore.

The front surfaceof the dynamic bodyfurther comprises a plurality of front isolation gaps. Each front isolation gapis a circular groove with a rectangular cross section as shown in. The circular groove has a perpendicular central axis. In this embodiment there are five front isolation gaps. Each front isolation gapis concentric to a flow boreon a one-to-one basis. Each front isolation gapcomprises an inner walland outer wallconnected by a base. Each wallandis parallel to the bore axis of the paired flow boreand the baseis perpendicular to the bore axis of the paired flow bore.

The front isolation gapcreates a ring-shaped section of material, or “front isolation ring”, defined between the front isolation gapand the flow bore. As shown inthe depth of the front isolation gapfrom the front surfaceof the dynamic bodyis greater than the depth, or length, of the flow control system wear ring sectionof the flow borefrom the front surface. Specifically, the front isolation gapextends past the flow control system wear ring shoulder.

The back surfaceof the dynamic bodycomprises a plurality of first stay rod bores. Each first stay rod boreis a through bore connecting the frontand backsurfaces of the back flanges. Each first stay rod boreis configured to receive a first stay rod. In this embodiment the plurality of first stay rod boresare located in five groups of four with each group centered on a bore axis of one of the plurality of flow boreson a one-to-one basis. As can be seen in, each group of four first stay rod boresis distributed symmetrically about the longitudinal and vertical axes centered on each bore axis of the paired flow bore.

The back surfaceof the dynamic bodyfurther comprises a plurality of plunger system bores. Each plunger system boreis a threaded blind bore configured to receive a threaded end of a component of the plunger system. In this embodiment the plurality of plunger system boresare located in five groups of twelve with each group centered on a bore axis of one of the plurality of flow boreson a one-to-one basis. As can be seen in, in any one of the five groups each of the twelve plunger system boresis spaced evenly circumferentially at a constant distance from the bore axis of the paired flow boreforming a bolt circle. While it is common for a bolt circle to have the first bolt hole at o-degrees, that is on the vertical axis above the transverse axis, in this embodiment the bolt circle is rotated, or clocked, 15-degrees counterclockwise from the vertical axis.

The back surfaceof the dynamic bodyfurther comprises a plurality of back isolation gaps. Each back isolation gapis a circular groove with a rectangular cross section as shown in. In this embodiment there are five back isolation gaps. Each back isolation gapis concentric to a flow boreon a one-to-one basis. Each back isolation gapcomprises an inner walland outer wallconnected by a base. Each wallandis parallel to the bore axis of the paired flow boreand the baseis perpendicular to the bore axis of the paired flow bore.

The back isolation gapcreates a ring-shaped section of material, or “back isolation ring”, defined between the back isolation gapand the flow bore. As shown inthe depth of the back isolation gapfrom the back surfaceof the dynamic bodyis greater than the depth, or length, of the plunger system wear ring sectionof the flow borefrom the back surface. Specifically, the baseof the back isolation gapextends past the plunger system wear ring shoulder.

The assembly procedure of the high-pressure pumpis as follows: Referring now to, the dynamic sectionis assembled by first, inserting the flow control system wear ring sealinto the seal grooveof the flow control system wear ring sectionof the flow bore. Second, inserting the flow control system wear ringinto the flow control system wear ring sectionof the flow borewith the flow control system wear ringoriented such that the tapered surfaces match. The tapered surfaces are an interference fit with the amount of insertion controlled by the flow control system wear ringcontacting the flow control system wear ring shoulder.

Referring now to, the third assembly step for the dynamic sectionis to insert the plunger system wear ring sealin the seal grooveof the plunger system wear ring sectionof the flow bore. Second, the plunger system wear ringis inserted into the plunger system wear ring sectionof the flow borewith the plunger system wear ringoriented such that the tapered surfaces match. The tapered surfaces are an interference fit with the amount of insertion controlled by the plunger system wear ringcontacting the plunger system wear ring shoulder. Fourth, the plunger system sealis inserted in the plunger system wear ring. The insertion depth of the plunger system sealis also controlled by the plunger system wear ring shoulder. This completes the assembly of the dynamic sectionof the fluid end body.

Referring now to, the fluid end bodyis assembled by attaching the static sectionto the dynamic sectionusing the plurality of second stay rodsand the plurality of body fasteners. A first threaded endof each second stay rodis threaded into a corresponding second stay rod boreand torqued to specification. Second, the second stay rod boresof the static sectionare aligned with the second stay rodsnow protruding from the front surfaceof the dynamic bodyand the static sectionis abutted to the dynamic sectionwhile simultaneously inserting the second stay rodsinto the second stay rod bores. The plurality of body fastenersare threaded onto the second threaded endsof each of the plurality of second stay rodson a one-to-one basis. This completes the assembly of the fluid end body.

Referring now to, the multi-piece fluid endis assembled by first installing the plurality of fluid control systemsinto the plurality of flow boresof the multi-piece fluid endon a one-to-one basis. Each flow boreof the multi-piece fluid endcomprises the flow boreof the dynamic bodyand the flow boreof the static section. As can be seen ineach flow control systemengages each flow control system wear ringwhich provides a sealing surface and a locating surface for the flow control system.

Referring now to, the plurality of plunger systemsare installed in the plurality of flow boresof the dynamic bodyon a one-to-one basis. As can be seen ineach plunger systemengages each plunger system sectionwhich provides concentric alignment with the flow borefor the plunger system. Each plunger systemalso engages each plunger system sealkeeping fluid from leaking between the plunger systemand the dynamic body. Each plunger systemalso abuts each plunger system wear ringwhich, along with the back surfaceof the dynamic bodycontrols how far the plunger systemis inserted into the flow bore.

Referring now to, the plurality of discharge manifoldsare attached to the static section. Detailed descriptions of the discharge manifoldand its installation are found in the above referenced documents.

Referring now to, the plurality of suction manifoldsare attached to the static section. Detailed descriptions of the suction manifoldand its installation are found in the above referenced documents. This completes the assembly of the multi-piece fluid end.

Referring now to, the high-pressure pumpis assembled by attaching the multi-piece fluid endto the power endusing the plurality of first stay rods, plurality of spacers, plurality of fluid end fasteners, and plurality of pony rod clamps. A detailed description of the components and assembly procedure is provided in the above referenced documents.

In operation the front isolation gapcreates a fixed radial distance between the bore wall of the flow control system wear ring sectionof the flow boreand the inner wallof the front isolation gap. This fixed radial distance between the two surfaces results in a constant thickness of the front isolation ringbetween the two surfaces. Since the material has a constant thickness, the outward radial forces produced by the high-pressure fluid within the flow boreproduce an equal deflection in every radial direction. This equal deflection eliminates stress variations within the flow control system wear ringincreasing the life of the flow control system wear ringand reducing the likelihood of fluid leaking past either the flow control system wear ring sealor the flow control system. In the same manner, the back isolation gapcreates the back isolation ring, increasing the life of the plunger system wear ringand reducing the likelihood of fluid leaking past either the plunger system wear ring sealor the plunger system seal.

Without the isolation gapsand, the radial distance between the bore wall of the flow bore, specifically the flow control system wear ring sectionand plunger system wear ring section, and the surface of the dynamic bodywill necessarily be different at any circumferential point of the flow boredue to the rectilinear shape of the dynamic bodyand the circular shape of the flow bore. These different radial distances result in different material thicknesses and different radial deflections at every circumferential point around the flow bore. The different deflections increase the likelihood that fluid will leak internally or externally around the wear ringsand. The different deflections also result in different stresses around the circumference of the wear ringsand.

These differing stresses reduce the life of the wear ringsand. The isolation gapsandeliminate these problems by creating isolation ring sectionsandof even thickness about the flow control system wear ring sectionand plunger system section, respectively.

Another embodiment of a high-pressure pumpis shown in. High-pressure pumpcomprises another embodiment of discharge manifold. Discharge manifoldis comprised of traditional ‘frac iron’ fittings well known in the industry. High-pressure pumpmay be identical to high-pressure pumpwith the exception of the discharge manifold.

While the sections of the flow borehave been described exhaustively, some details of the flow borewere omitted for brevity. Such details may include the transition areas between each section of the flow borewhich may include radii and/or chamfers as needed to reduce stress concentrations due to the changes in diameter along the flow bore.

In the disclosed embodiments the isolation gapsandhave a constant width, straight side walls, and a flat base. Any of these features may be altered to allow for design and or fabrication considerations. Also, the depth of the isolation gaps is as deep as the section of the flow bore within which the affected component, namely the wear ring, is installed. The depth may be greater or lesser if required. A lesser depth may reduce the effectiveness of the isolation gap but still provide a benefit. Additionally, the flow bore and isolation gap in the described embodiments are circular, they may be of any cross-sectional shape and still derive the benefit of having a constant material thickness due to an isolation gap. It is also contemplated that isolation gaps be added to existing fluid ends as a retrofit improvement.

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