FRACK PUMP FLUID END WITH INTEGRATED HYDRAULIC VALVE SEAT RELEASE

Abstract

A hydraulic valve seat release system for a fluid end of a high pressure pump, comprised of method and apparatus for releasing a valve seat having a tapered outer diameter for sealingly mating when installed in the tapered interior of a fluid end suction or discharge bore via interference fit. The fluid end module of the invention includes internal high pressure porting between an exterior surface of the fluid end module and the interior surface of the bore, whereby high pressure fluid may be applied to the tapered surface of the bore and into a fluid channel around the circumference of the tapered outer diameter of the valve seat. The high pressure fluid compresses the outer diameter of the valve seat and expands the interior diameter of the bore in order to disrupt the interference fit between the valve seat and the bore thereby releasing the valve seat.

Description

CROSS-REVERENCE TO RELATED APPLICATIONS

The earlier effective filing date of U.S. Application Ser. No. 61/906,017, entitled “Frack Pump Fluid End with Integrated Hydraulic Valve Seat Release”, filed Nov. 19, 2013, in the name of the inventors Steven K. Deel and Randal S. Newman. This application is also hereby incorporated by reference for all purposes as if set forth verbatim herein.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND

1. Field

The presently disclosed technique relates to fluid ends for high pressure pumps used in oil and gas field, production, such as well servicing and hydraulic, fracturing operations, and more particularly to a valve seat release system and method of use with such fluid ends.

2. Discussion a Related Art

This section of this document introduces information about and/or from the art that may provide context for or be related to the subject matter described herein and/or claimed below. It provides background information to facilitate a better understanding of the various aspects of the subject matter disclosed and claimed below. This is a discussion of “related” art. That such art is related in no way implies that it is also “prior” art. The related art may or may not be prior art. This discussion is therefore to be read in this light, and not as admissions of prior art.

The majority of high pressure pumps used in the oilfield for well service and hydraulic fracturing utilize replaceable valve seats. These valve seats have a tapered outside diameter (OD) and are installed into tapered bores machined into the fluid end module. When installed the design of the tapered bores creates an interference fit between the valve seat and the module. This interference fit creates a fluid tight seal in order to prevent leakage between the valve seat and module.

As a result of this interference fit, removal of the valve seat for replacement is often difficult and at times requires specialized tools. Historically an external hydraulic cylinder and puller rod assembly has been used to pull the valve seat free of the tapered interference fit in the module. It is not uncommon to see forces of 20-30 tons required to remove tapered valve seats from the fluid end module and standard valve puller designs are capable of 170 tons of pull.

In addition to the concerns noted above when using external valve seat pullers, the design of some fluid ends do not allow the use of external puller assemblies. Fluid end configurations such as the “Y” block have intersecting bores offset by 120° as opposed to valves and seats being inline or stacked vertically. In this configuration the discharge valve seats can be removed, with an external valve seat puller, however the suction valve seats are not accessible. In this case, workers typically use a steel bar and sledgehammer to knock the valves out from the lower suction bore.

Furthermore, some fluid end designs such as the “Y” block noted above require the user to remove the suction manifold in order to gain access to the bore below the valve seat resulting in increased time requirements for maintenance. Use of conventional valve seat pullers requires time to install, use, and remove which can be a time consuming task.

The presently disclosed technique is directed to resolving, or at least reducing, one or all of the problems mentioned above. Even if solutions are available to the art to address these issues, the art is always receptive to improvements or alternative means, methods and configurations. Thus, there exists a need for technique such as that disclosed herein.

SUMMARY

In a first aspect, a hydraulic valve seat release system for a fluid end of a high pressure pump, comprises: a fluid end block defining at least one of a suction bore and a discharge bore; a pressure port communicating between an exterior surface of the block and the at least one bore, the bore having a tapered interior surface; a valve seat having a tapered outer diameter and structured that in use sealably mating with the interior surface of the bore; and wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with the pressure port,

In a second aspect, a method for releasing a valve seat of a high pressure pump comprises: sealably mating the valve seat within at least one of a suction bore and a discharge bore, the at least one bore being defined within a fluid end block and having a pressure port communicating between an exterior surface of the block and the bore, the bore having a tapered interior surface, the valve seat having a tapered outer diameter, and the valve seat and the bore when mated defining an annular conduit being in pressure communication with the pressure port; attaching a high pressure fluid source to the pressure port on the exterior surface of the block; applying a high pressure fluid from the source through the pressure port to the annular conduit; and releasing the valve seat by at least one of constricting the valve seat or expanding the bore by means of the fluid.

In a third aspect, a method for the manufacture of a hydraulic valve release system for a fluid end of a high pressure pump comprises: forging a fluid end block; machining at least one of a suction bore and a discharge bore within the block, the at least one bore having a tapered interior surface; machining a high pressure port communicating between an exterior surface of the block and the bore; forging or casting a valve seat having a tapered outer diameter for sealably mating with the bore; and forming, a circumferential annular conduit within at least one of the bore interior surface and the valve seat outer diameter wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with the pressure port,

In a fourth aspect, a hydraulic valve seat for a fluid end of a high pressure pump comprises: the valve seat having a tapered outer diameter and a circumferential annular conduit within the outer diameter, the valve seat structured that in use sealably mating with a tapered interior surface of at least one of a suction bore and a discharge bore, the at least one bore defined within a fluid end block; and wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with a pressure port communicating between an exterior surface of the block and the interior surface of the bore.

In a fifth aspect, a method for the manufacture of a hydraulic valve seat for a fluid end of a high pressure pump comprises: forging or casting the valve seat having a tapered outer diameter for sealably mating with a tapered interior surface of at least one of a suction bore and a discharge bore, the at least one bore defined within a fluid end block: and forming a circumferential annular conduit within the valve seat outer diameter wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with a pressure port communicating between an exterior surface of the block and the interior surface of the bore.

The above presents a summary of the presently disclosed subject matter in order to provide a basic understanding of some aspects thereof. The summary is not an exhaustive overview, nor is it intended to identify key or critical elements to delineate the scope of the subject matter claimed below. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description set forth below.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter disclosed and claimed below may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:

FIG. 1A-FIG. 1B are a partially sectioned views of a conventional Y-block fluid end of a high pressure pump.

FIG. 2A-FIG. 2B depict a quintuple valve-over-valve fluid end block of a high pressure pump according to an embodiment of the presently disclosed technique.

FIG. 3A-FIG. 3B are cross sectional views of a valve-over-valve fluid end block according to an embodiment of FIG. 2 taken along line A-A therein, and a detailed view of the suction bore of FIG. 3A, respectively.

FIG. 4A-FIG. 4B are side views of a valve seat assembly according to another embodiment and a cross sectional view of a valve seat and valve according to the embodiment

FIG. 4A taken along line B-B therein, respectively.

FIG. 5 is a side view of a quintuple Y-block fluid end of a high pressure pump according to another embodiment.

FIG. 6 is a cross sectional view of a Y-block fluid end according to the embodiment of FIG. 5 taken along line C-C therein.

FIG. 7A-FIG. 7B are side views of a valve seat according to another embodiment a cross sectional view of a valve seat according to an embodiment of FIG. 7A taken along line D-D therein, respectively.

While the invention is susceptible to various modifications and alternative forms, the drawings illustrate specific embodiments herein described in detail by way of example. It should be understood, however, that the description herein of specific embodiments is not intended to limit the invention to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

DETAILED DESCRIPTION

Illustrative embodiments of the subject matter claimed below will now be disclosed. In the interest of clarity, not all features of an actual implementation are described in this specification. It will be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions will be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort, even if complex and time-consuming, would be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.

In order to address the limitations created with the use of external valve seat pullers, the presently disclosed technique includes fluid end modules with internal porting whereby high pressure hydraulic fluid and or grease can be applied to the tapered bore of the fluid end. When applied, this pressure compresses the valve seat and expands the fluid end bore, thereby freeing the valve seat from the tight interference fit.

This design includes, in some embodiments, valve seats with O-ring grooves machined on the tapered OD as well as a annular conduit machined in between the O-ring grooves. In some embodiments, the grooves may be machined in the wall of the bore. Elastomeric O-rings are installed in the grooves prior to the valve seat being installed in the fluid end module. When installed in the fluid end module, the O-rings create a fluid tight seal. The tapered contact surfaces of the seat and fluid end bore create and maintain the interference fit of the seat during operation of the pump.

Within the fluid end module, a pressure port is machined from an outside surface of the module and terminates in the tapered bore in an area between where the two O-rings are located. The outside surface of the module may, for example, be machined for a high pressure autoclave adapter to which a high pressure pump is connected during removal.

Removal of the valve seats is performed by attaching a high pressure pump to the autoclave fitting noted above. As hydraulic pressure is applied to the port, fluid enters the fluid end, flows to the valve seat around the relief groove cut between the two O-rings. As pressure is increased, the valve seat is compressed and the bore in the fluid end module is expanded. This action breaks the metal to metal interference seal between the valve seat and fluid end module. Due to the tapered bore the valve seat can only move in one direction, upward.

Due to the high pressures the fluid ends are subjected to, at times in excess of 20,000 psi, certain considerations should be considered in the design of the integrated hydraulic valve seat release (“HVSR”). Such considerations include a pumping media bypass. in the event of an O-ring failure the system should withstand pressures generated by the primary pump. In the event of a crack or fluid washout in the tapered valve seat bore, the system should withstand the pressure generated by the primary pump. Such concerns also include the potential failure of O-ring to maintain pressure from the hydraulic pump when removing the valve seat. Should this occur, use of a conventional hydraulic valve seat puller would be useful.

Turning now to the drawings, FIG. 1A illustrates a conventional Y-block fluid end module 100 of a high pressure pump and FIG. 1B is an enlargement of the fragment B in FIG. 1A. The fluid end module 100 includes fluid cylinder 102, plunger 104, suction bore 110, and discharge bore 112. Valve seats 106, 108 are installed within the suction bore 110 and discharge bore 112, and designed with a tapered outer diameter to create an interference fit with the correspondingly tapered interior wail of the respective bore 110, 112. The discharge valve seat 108 is fitted with an O-ring 114 to maintain a fluid seal between the seat 108 and the discharge bore 112. Valve members 115, 118 sit within the valve seats 105, 108 and are spring biased in closed positions against the seats 106, 108 by valve springs 120. The top of the discharge bore 112 is sealed off with a discharge valve cover 122 fitted with an O-ring 124 and secured by way of retainer nut 126. Within the suction bore 110 the valve member 116 is held in position by means of suction valve guide 128. retainer 130, pin 132, and pin keeper 134.

FIG. 2A-FIG. 2B, and FIG. 3A-FIG. 3B illustrate one particular embodiment in a quintuple valve-over-valve fluid end module 200 in accordance with the presently disclosed technique. FIG. 2A-FIG. 2B more particularly illustrate the fluid end module 200 in a top, plan view and an elevational view, respectively. FIG. 3A is a sectioned view along line A-A in FIG. 2A. FIG. 3B is an enlarged view of region B indicated in FIG. 3A. The fluid end module 200 includes a discharge flange 202, a gauge connection 204, a discharge flange 206, a retainer nut and cover 208, and a suction manifold stud and nut 210. The fluid end module also includes a plurality of hydraulic ports 208 (only one indicated), at least one for each valve 206.

Turning now to FIG. 3A-FIG. 3B, suction bores 300 and discharge bores 302 are defined within the fluid end block 212, the interior surface 304, 306 of each bore being tapered for interference fit with the correspondingly tapered outer diameter of the valve seat 308, 310. While differences exist between suction bores and discharge bores, various embodiments operate and function substantially the same for each bore type, and therefore discussion in reference to a suction bore shall apply equally as a discussion to a discharge bore. Any use of bore or bores without distinction shall also be construed as applying to either a suction bore or discharge bore.

Referring now to FIG. 3B, the valve seat 308 is in its installed position within the bore 300, a annular conduit 312 around the circumference of the outer diameter of the valve seat 308, aligns with a hydraulic port 210 that provides high pressure fluid communication between the interior surface 304 of the bore 300 and the exterior surface 314 of the fluid end block 212. A high pressure fixed coupling 316 is attached to the hydraulic port 210 at the block's exterior surf 314.

To unseat the valve seat, a high pressure pump or other source of high pressure fluid (not shown) is attached to the coupling 316 and fluid is pumped through the port 210 to the annular conduit 312 of the valve seat 308. The high pressure of the fluid causes either the outer diameter of the valve seat 308 to constrict or the interior surface 304 of the bore 300 to expand, or both, thereby releasing the interference fit between the valve seat 308 and the bore 300 to allow removal of the valve seat 308.

In order to remove and replace the valve seats, whether from a fluid end configured as valve-over-valve or a Y-block, one particular sequence of steps comprises first removing the discharge cover, followed by the valve spring and discharge valve. A high pressure fluid source is then attached to the high pressure fixed coupling and high pressure fluid is introduced into the annular conduit via the hydraulic port. The increased pressure acts to compress the circumference of the valve seat and/or expand the diameter of the interior surface of the bore thereby interrupting the interference fit between the valve seat and the bore. Once released, or dislodged, the valve seat may be removed.

Once the discharge valve has been removed, the suction bore can be accessed. One particular sequence for removal of the valve seat from the suction bore comprises first removing the suction valve pin, retainer, guide and spring. A high pressure fluid source can then he attached to the high pressure fixed coupling of the suction bore's hydraulic port and the valve seat released by high fluid pressure as discussed above for the discharge bore's valve seat.

In FIG. 3B, the outer diameter of the valve seat 308 is further installed with two O-rings 318, 320: an upper O-ring 318 above the annular conduit 312 and a lower O-ring 320 below the annular conduit 312. The O-rings 318, 320 provide a fluid-tight seal sufficient to keep the high pressure fluid introduced through the hydraulic port 210 from leaking into the bore 300 until the interference fit is sufficiently released to allow removal of the valve seat 308, 310.

Alternative embodiments of the presently disclosed technique may also be realized. For example, FIG. 4A and FIG. 4B illustrate one particular embodiment of a double O-ring valve assembly 400. FIG. 4A is an elevational view and FIG. 4B is a sectioned view along line B-B in FIG. 4A. The valve assembly includes a valve member 402 seated on the valve seat 404. The valve seat 404 includes tapered outer diameter 406 into which a annular conduit 408 is formed and upper and lower O-rings 410, 412 are fitted. The interior surface of the bore (not shown) is finished smoothly. Thus, the annular conduit and the O-rings may be place on either the interior surface of the bore as in FIG. 3A and FIG. 3B or on the valve seat as in FIG. 4A and FIG. 4B. Note also that there may be embodiments wherein the annular conduit is formed on either the interior surf of the bore or on the valve seat and the O-rings are place on the other of those two locations.

FIG. 5 and FIG. 6 illustrate another particular embodiment 500 of the hydraulic valve seat release system in a fluid end Y-block module. FIG. 5 is an elevational view and FIG. 6 is a sectioned view along line C-C in FIG. 5. In FIG. 5 and FIG. 6, like parts to the embodiment of FIG. 2A-FIG. 2B and FIG. 3A-FIG. 3B bear like numbers. Note how readily the technique may be adapted to different configurations of the fluid end module.

FIG. 7A and FIG. 7B illustrate modification of a conventional single O-ring valve seat 700 in accordance with the presently disclosed technique. FIG. 7A is an elevational view of the valve seat 700 and FIG. 7B is a sectioned view along the line D-D in FIG. 7A. The valve seat is modified by machining of an annular conduit 702 into the tapered exterior surface 704 of the valve seat in a position below the existing O-ring channel 706, and further adding a lower O-ring channel 708 below the annular conduit 702. Those ordinarily skilled in the art having the benefit of this disclosure will be able to readily implement such a modification with existing knowledge and tooling.

In an alternate embodiment (not shown), the annular conduit surrounding the circumference of the valve seat is formed by a fluid channel in the tapered interior surface of the bore, rather than the valve seat itself having a fluid channel. In this embodiment, a circumferential annular conduit is defined in combination by the interior surface of the bore and valve seat when sealingly mated with the annular conduit being in fluid communication with the hydraulic port,

Those in the art having the benefit of this disclosure will appreciate that the sealing elements other than O-rings might be used in various alternative embodiments. Thus, the O-rings disclosed herein are, by way of example and illustration, just one means for sealing by which the disclosed sealing function may be implemented. Indeed, some embodiments may not even need to use separate sealing elements where appropriate levels of sealing can he achieved without them.

Similarly, the placement of the annular conduit and any sealing elements, where used, is not material so long as they provide a fluid-tight seal sufficient to keep the high pressure fluid introduced through the hydraulic port from leaking into the bore until the interference fit is sufficiently released to allow removal of the valve seat. Thus, various embodiments might use a conventional valve seat with a groove cut in the block; or, a valve seat with a groove therein and block, with a groove therein; or, a valve seat with a groove but no sealing element on either the block or seat; or a block with to groove therein and no sealing element on block or seat; or those embodiments disclosed herein. These, and still other variations, are all within the scope of the subject matter claimed below.

Valve seats in accordance with the presently disclosed technique may be manufactured from forgings or castings. Such forgings and castings are well known in the art and any suitable forging or casting technique known to the art may be used Accordingly, so as to avoid obscuring that which is otherwise disclosed and claimed herein, further discussion of such techniques shall be omitted. The annular conduit may be formed in the valve seat by the castings, or by machining. Any portion of the annular conduit formed in the interior surface of the bore may be formed by machining, and hydraulic ports may be machined into the forged fluid end block.

The presently disclosed technique therefore includes method and apparatus for releasing a valve seat from a suction bore or a discharge bore of a high pressure pump fluid end. A valve seat having a tapered outer diameter for sealingly mating with the tapered interior diameter of a fluid end bore via interference fit. The fluid end module includes internal high pressure porting between an exterior surface of the fluid end module and the interior surface of the bore, whereby high pressure fluid may be applied to the tapered surface of the bore and into a fluid channel around the circumference of the tapered outer diameter of the valve seat. The high pressure fluid compresses the outer diameter of the valve seat and expands the interior diameter of the bore in order to disrupt the interference tit between the valve, seat and the bore, thus releasing, the valve seat. The valve seats are, in some embodiments, installed with two O-rings one above and one below the valve seat fluid channel—providing a fluid tight seal.

This concludes the detailed description. The particular embodiments disclosed above are illustrative only, as the invention may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the invention. Accordingly, the protection sought herein is as set forth in the claims below.

Claims

1. A hydraulic valve seat release system for a fluid end of a high pressure pump, comprising:

a fluid end block defining, at least one of a suction bore and a discharge bore;

a pressure port fluidly communicating between an exterior surface of the block and the at least one bore, the bore having a tapered interior surface; and

a valve seat having a tapered outer diameter that, in use, sealably mates with the inter or surface of the bore;

wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with the pressure port and fluidly sealed from the bore.

2. The hydraulic valve seat release system of claim I wherein the annular conduit is defined at least in part by the interior surface of the bore.

3. The hydraulic valve seat release system of claim 2, wherein the annular conduit is further defined at least in part by the outer diameter of the valve seat.

4. The hydraulic, valve seat release system of claim 12, wherein the annular conduit is defined at least in part by the outer diameter of the valve seat.

5. The hydraulic valve seat release system of claim 1, further comprising at least one sealing element sealing the annular conduit from the bore.

6. The hydraulic valve seat release system of claim 5, wherein the sealing element comprises means for sealing the fluid conduit from the bore.

7. The hydraulic valve seat release system of claim 6, wherein the means for sealing comprises an elastomeric O-ring.

8. The hydraulic valve seat release system of claim 5, wherein the sealing element comprising an elastomeric O-ring.

9. A method for releasing a valve seat in the fluid end block of a high pressure pump, comprising:

sealably mating the valve seat within at least one of a suction bore and a discharge bore;

applying a high pressure fluid through a pressure port extending from the external surface of the fluid end block to an annular conduit defined by at least one of the interior surface of the bore and the valve seat when the interior surface and the valves seat are mated; and

releasing the valve seat by constricting the valve seat or expanding the bore by means of the fluid.

10. The method of claim 9, wherein the annular conduit is defined by the interior surface of the bore.

11. The method of claim 10, wherein the annular conduit is further defined by the valve seat.

12. The method of claim 9, wherein the annular conduit is defined by the valve seat.

13. The method of claim 9, wherein sealably mating the valve seat with at least one of the suction bore and the discharge bore includes disposing at least one sealing element to fluidly seal the annular conduit from the bore.

14. The method of claim 13, wherein the sealing element comprises an elastomeric O-ring.

15. A method for the manufacture of a hydraulic valve release system for a fluid end of a high pressure pump, comprising:

forging a fluid end block;

machining at least one of a suction bore and a discharge bore within the block, the at least one bore having a tapered interior surface;

machining a high pressure port communicating between an exterior surface of the block and the bore;

forging or casting a valve seat having a tapered outer diameter for sealably mating with the bore; and

forming a circumferential annular conduit within at least one of the bore interior surface and the valve seat outer diameter wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with the pressure port.

16. A hydraulic valve seat for a fluid end block of a high pressure pump, comprising;

the valve seat having a tapered outer diameter and a circumferential annular conduit within the outer diameter, the valve seat structured so that in use the valve seat sealably mates with a tapered interior surface of at least one of a suction bore and a discharge bore, the at least one bore defined within a fluid end block; and

wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with a pressure port communicating between an exterior surface of the block and the interior surface of the bore.

17. The hydraulic valve seat of claim 16, wherein the valve seat defines the annular conduit in conjunction with the interior surface of the bore.

18. The hydraulic valve seat of claim 16, wherein the valve seat defines the annular conduit to the exclusion of the interior surface of the bore.

19. The hydraulic valve seat of claim 16, wherein the valve seat includes at least one channel in which a sealing element may be disposed.

20. A method for the manufacture of a hydraulic valve seat for a fluid end of a high pressure pump, comprising:

forming the valve seat having a tapered outer diameter for sealably mating with a tapered interior surface of at least one of a suction bore and a discharge bore, the at least one bore defined within a fluid end block; and

forming a circumferential annular conduit within the valve seat outer diameter wherein the valve seat and the bore when mated define an annular conduit being in pressure communication with a pressure port communicating between an exterior surface of the block and the interior surface of the bore.