Fluid end assembly

Abstract

A fluid end for a high-pressure pump. The fluid end includes a pump housing having a plunger bore within which is positioned a reciprocating plunger. Extending upwardly at an incline from the inner end of the plunger bore is a discharge passage. Extending downwardly at an incline from the inner end of the plunger bore is a suction passage. Discharge and suction valves are secured, respectively, within the discharge and suction passages.

Description

FIELD OF THE INVENTION

[0001] The present invention relates generally to pumps having pumping chamber pressure-responsive fluid distributors and, more particularly, to such pumps having distributors positioned opposite the pumping member's end face.

BACKGROUND OF THE INVENTION

[0002] It is often difficult to produce hydrocarbons in an economic manner from low permeability reservoir rocks. Production rates are often boosted by resorting to hydraulic fracturing, a technique that increases rock permeability by opening channels through which hydrocarbons can flow to recovery wells. During hydraulic fracturing, a fluid is pumped into the earth under high pressure (sometimes as high as 50,000 PSI) where it enters a reservoir rock and cracks or fractures it. Proppants are carried in suspension by the fluid into the fractures. When the pressure is released, the fractures partially close on the proppants, leaving channels for oil and gas to flow.

[0003] Specialized pumps are used to develop the pressures necessary to complete a hydraulic fracturing procedure or “frac job.” These pumps are usually provided with fluid ends having both reciprocating plungers that place fluids under pressure and valves that control fluid flow to and from the plungers. The body of a fluid end is typically a collection of parts releasably fastened together to provide access to internal components for servicing. Unfortunately, the joints between the parts and the supporting features for the valves tend to weaken the body of a fluid end, limiting its pressure rating, and making it susceptible to corrosion, leaks and cracks as high, cyclic stresses take their toll. Thus, it is not unusual for the bodies of fluid ends to prematurely fail under load, cutting short their useful lives.

[0004] In an effort to reduce the number of failures of fluid ends, “Y-type” fluid ends have been proposed. As is well known, Y-type fluid ends reduce concentrated stresses in the body of a fluid end by increasing the angles at which bores within the body intersect one-another above 90° to about 120°. Unfortunately, none of the proposed Y-type designs have seen widespread use or great commercial success since such have been difficult and costly to manufacture and equally difficult to service in the field. A need, therefore, exists for an improved Y-type fluid end.

SUMMARY OF THE INVENTION

[0005] In light of the problems associated with the known fluid end employed in high-pressure pumps that are prone to premature fatigue failures, it is a principal object of the invention to provide a fluid end assembly having a Y-type configuration that is very robust, neither being prone to wear quickly nor fail under repeated cyclic loading present during normal usage. Should parts of the fluid end assembly wear or break during use, such are easy to repair or replace. No special tools are required to accomplish the task.

[0006] It is another object of the invention to provide a fluid end assembly of the type described that is relatively compact in size and is easy to transport. The fluid end assembly can be truck-, trailer-, and skid-mounted to further facilitate its transport to and from the “oil patch.”

[0007] It is a further object of the invention to provide a Y-type fluid end assembly of the type described whose internal, fluid flow passageways have the shortest practicable lengths so as to minimize pressure losses as fluid moves through the fluid end. The passageways are configured, in terms of the shapes of their sidewalls and their positions relative to one another, so as to minimize pressure losses as fluid moves through the fluid end assembly. Thus, the fluid end assembly of this invention is believed to be more efficient than conventional, fluid end designs.

[0008] Still another object of the invention is to provide a fluid end assembly that features turbulence-reducing suction and discharge valves. The valves reduce pressure losses as fluids move through the fluid end assembly thereby increasing the efficiency of the fluid end assembly. The valves are configured such that major portions of both can be removed from the assembly from a single accessway for repair and replacement, conserving the operator's time and resources.

[0009] It is an object of the invention to provide improved elements and arrangements thereof in a fluid end assembly for the purposes described which is lightweight in construction, inexpensive to manufacture, and fully dependable in use.

[0010] Briefly, the fluid end assembly in accordance with this invention achieves the intended objects by featuring a pump housing with a plunger bore having a closed inner end and an open outer end. A suction passage intersects the plunger bore and a discharge passage intersects both the plunger bore and the suction passage such that the discharge passage, the suction passage and the plunger bore radiate from their point of intersection to define a shape resembling a “Y”. An outlet passage intersects the discharge passage substantially at right angles. A reciprocating plunger is located in the plunger bore whereas a suction valve is located in the suction passage and a discharge valve is located in the discharge passage. A fluid supply manifold is secured to the pump housing and is in fluid communication with the suction passage.

[0011] The foregoing and other objects, features and advantages of the present invention will become readily apparent upon further review of the following detailed description of the preferred embodiment as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

[0012] The present invention may be more readily described with reference to the accompanying drawing that is a cross-sectional view of a fluid end assembly in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Referring now to the drawing, a fluid end assembly in accordance with the present invention is shown at 10. Fluid end assembly 10 includes a pump housing 12 having a plunger bore 14 within which a plunger 16 reciprocates. At its inner end, plunger bore 14 terminates in a pumping chamber 18 that is supplied with fluid by a suction passage 20 in pump housing 12. Fluid pressurized by plunger 16 exits pumping chamber 18 through a discharge passage 22 in pump housing l2. Fluid flow through suction and discharge passages 20 and 22 is controlled by means of suction and discharge valves 24 and 26 located therein. Suction valve 24 connects a fluid supply manifold 28 to suction passage 20 and discharge valve 26 ports fluid from discharge passage 22 into an outlet passage 30 for release from fluid end assembly 10.

[0014] Pump housing 12 is a steel forging whose overall height and width are substantially the same, making such compact and relatively easy to transport. To lower weight and increase strength, housing 12 is provided with a plunger section 32 of reduced height that contains plunger bore 14 and is adapted for attachment to the power end 34 of a high-pressure pump by a plurality of stay rods 36. A suction section 38, containing suction passage 20, is integrally formed with plunger section 32 and extends forwardly and downwardly from plunger section 32. Similarly, a discharge section 40, containing discharge passage 22, is integrally formed with plunger and suction sections 32 and 38 and extends forwardly and upwardly from plunger section 32. Suction and discharge sections 38 and 40 taper from their inner ends, where such are at least 2.5 times the width of the passage 20 or 22 they contain, to their outer ends where such are about 1.5 times the width of contained passage 20 or 22.

[0015] Plunger bore 14 is provided within pump housing 12 along a first centerline A. At its outer end, plunger bore 14 is widened and partly threaded at 42 to receive a packing and gland nut unit 44 giving a fluid-tight seal around plunger 16. A lubricating port 46 in plunger section 32 permits lubricant to be provided to plunger 16 within the packing and gland nut unit 44. As was noted above, at its inner end, plunger bore 14 terminates in pumping chamber 18.

[0016] Suction passage 20 intersects plunger bore 14 and has a second centerline B that is coplanar with first centerline A and intersects first centerline A at a first reference point AB to define a first obtuse angle. Suction passage 20 extends from the bottom to the top of suction section 38 of pump housing 12. Preferably, suction passage 20 has a zone of reduced diameter extending upwardly from the bottom of suction section 38 to a point about halfway to pumping chamber 18. The top of the zone of reduced diameter forms a deck 48 upon which a cylindrical, suction valve seat 50 rests.

[0017] Discharge passage 22 intersects both plunger bore 14 and suction passage 20 and has a third centerline C. Third centerline C is coplanar with second centerline B and first centerline A that it intersects at a second reference point AC so as to define a second obtuse angle Additionally, discharge passage 22 has a zone of reduced diameter extending between the bottom of discharge passage 22 and about the midpoint of discharge passage 22 the top of which defines a deck 52 upon which a cylindrical, discharge valve seat 54 rests. The bottom of deck 52, like the bottom of deck 48, slopes outwardly and upwardly at an angle of approximately 30°. This slope allows decks 48 and 52 to transfer forces imparted by valve seats 50 and 54 evenly to pump housing 12 thus reducing the likelihood of fatigue-induced cracks forming in housing 12 at these locations.

[0018] Discharge passage 22 and seat 54 are provided with diameters that are greater than that of suction valve seat 50 and the piston 56 that engages valve seat 50. With plunger 16 positioned at the beginning of its stroke into pumping chamber 18, suction valve seat 50 and piston 56 can be pulled from pump housing 12 through discharge passage 22 for inspection, repair or replacement. Thus, plunger 16 does not have to be removed from pump housing 12 to service suction valve 24.

[0019] Reference points AB and AC are spaced along first centerline A with reference point AB being located nearer to the threaded end 42 of plunger bore 14 to facilitate the movement of fluid from pumping chamber 18 into discharge passage 22. Obtuse angle, measuring about 125°, is greater than obtuse angle , measuring about 115°, to facilitate access to suction passage 20 and valve 24. The resulting Y-shaped configuration offered by the intersections of plunger bore 14, suction passage 20, discharge passage 22 and their associated centerlines A, B and C reduces stresses within pump housing 12 during use and minimizes the likelihood of pump housing 12 failing over time.

[0020] Outlet passage 30 extends through discharge section 40 from one of its ends to the other. To either end of discharge section 40 can be connected one or more conduits (not shown) to carry pressurized fluid away from fluid end assembly 10. This pressurized fluid is, of course, used to perform work.

[0021] Manifold 28 includes a tubular body 58 from which a tubular connector 60 extends upwardly to place tubular body 58 and suction passage 20 in fluid communication with one another. Connector 60 is axially aligned with centerline B and admits the bottom of suction valve 24 into manifold 28 to reduce the height of fluid end assembly 10. The top of connector 60 is provided with a radial flange 62 that, by means of threaded fasteners 64, is attached to the bottom of suction section 38 of pump housing 12. The opposite ends of tubular body 58 are open and connected to a fluid source when fluid end assembly 10 is operated.

[0022] Suction valve 24 has valve seat 50 and piston 56 movably joined to valve seat 50. Piston 56 has a head 66 for engaging the top of valve seat 50 and a stem 68 extending downwardly from head 66 through valve seat 50. A valve guide 70 is positioned adjacent the bottom of valve seat 50 and slidably receives stem 68. A valve keeper 72 is fitted upon stem 68 such that valve guide 70 is disposed between valve seat 50 and keeper 72. A keeper pin 74 is slidably positioned within a transverse aperture 76 in stem 68 and abuts the bottom of keeper 72. A compressed spring 78 is positioned between, and exerts opposing forces upon, valve guide 70 and keeper 72 so as to normally retain head 66 in flush engagement with the top of valve seat 50 thus closing suction valve 24.

[0023] Discharge valve 26 includes valve seat 54 and a piston 80 for engaging valve seat 54. Piston 80 has a stem 82 that extends upwardly from a head 84 away from valve seat 54 and into a socket 86 in a valve guide 88 retained in passage 22 by a threaded discharge nut 90. A number of apertures 92 traverse guide 88 and intersect socket 86 to provide pressure relief to socket 86. A compressed spring 94 is disposed between valve guide 88 and head 84 for normally retaining head 84 in flush engagement with the top of valve seat 54 and keeping discharge valve 26 closed. When plunger 16 pressurizes fluid in chamber 18, the fluid flows through seat 54, past head 84, and into outlet passage 30.

[0024] Plunger 16 is a hollow cylinder that is open at its outer end and is closed at its inner end. As shown, the outer end of plunger 16 is provided with a central recess 96 surrounded by a plurality of threaded apertures 98. The inner end of plunger 16, on the other hand, is tapered and rounded at 100 in a manner resembling the tip of a bullet. It is believed that this bullet-like configuration reduces turbulence and pressure losses within pumping chamber 18, especially as plunger 16 travels forward, thereby displacing fluid from pumping chamber 18 more efficiently.

[0025] A pony rod extension 102 connects the reciprocating crosshead (not shown) of power end 34 to plunger 16 and allows plunger 16 to be removed from pump housing 12 without need to remove housing 12 from power end 34. Rod extension 102 includes a pony rod 104 for attachment to a reciprocating crosshead and a pony rod adapter 106 that connects pony rod 104 to plunger 16. Preferably, pony rod 104 is a hollow cylinder that has an integral plug 108 at one of its ends and a radial flange 110 at the other of its ends. Plug 108 has a central socket 112 surrounded by a plurality of threaded apertures 114 and flange 110 has a plurality of apertures 116 through which threaded fasteners (not shown) are extended to fasten pony rod 104 to a crosshead. Adapter 106, however, includes a cylindrical body 118 having an outer diameter that is less than that of both plunger 16 and pony rod 104. Apertured peripheral flanges 120 and 122 at the opposite ends of cylindrical body 118 permit threaded fasteners 124 to pass into apertures 98 and 114 and connect adapter 106 to both plunger 16 and pony rod 104. Pins 126 and 128 extend from the opposite ends of adapter 106 for snug positioning, respectively, in central socket 112 and recess 96 to ensure that the axial alignment of pony rod 104, adapter 106 and plunger 16 is maintained at all times while assembly 10 is in operation.

[0026] Fluid end 10 produces useful work by pressurizing fluid by means of the reciprocating action of plunger 16. Valves 24 and 26, of course, permit fluid pressurized by plunger 16 to move only in one direction from manifold 28 to outlet passage 30. The Y-shaped configuration of bore 14 and passages 20 and 22 in addition to the thick, tapered walls provided to plunger, suction and discharge sections 32, 38 and 40 pump housing 12 with a construction that is durable and not prone to fail under repeated cyclic loading developed by plunger 16. Should plunger 16, valves 24 and 26, packing and gland nut unit 44, or pony rod extension 102 ever require servicing, such are easy to repair or replace with ordinary tools and without major disassembly of fluid end assembly 10.

[0027] While the invention has been described with a high degree of particularity, it will be appreciated by those skilled in the art that modifications may be made thereto. Therefore, it is to be understood that the present invention is not limited to the sole embodiment described above, but encompasses any and all embodiments within the scope of the following claims.

Claims

1. A pump housing for a fluid end assembly, comprising: a metal forging having: a plunger bore for receiving a reciprocating plunger, said plunger bore being oriented along a first centerline and having a closed inner end and an open outer end; a suction passage intersecting said plunger bore for receiving a suction valve, said suction passage being oriented along a second centerline that is coplanar with said first centerline and that intersects said first centerline at a first reference point so as to define a first obtuse angle; a discharge passage intersecting both said plunger bore and said suction passage for receiving a discharge valve, said discharge passage being oriented along a third centerline that is coplanar with said second centerline and said first centerline and that intersects said first centerline at a second reference point that is closer to said open outer end than said first reference point so as to define a second obtuse angle; and, an outlet passage intersecting said discharge passage substantially at right angles.

2. The pump housing for a fluid end assembly according to claim 1 wherein said suction passage and said discharge passage are each provided with portions of reduced diameter that define valve-supporting decks at their tops.

3. The pump housing for a fluid end assembly according to claim 1 wherein said discharge passage has a diameter that is greater than that of said suction passage so that, when servicing is required, the suction valve can be removed from said pump housing through said discharge passage.

4. The pump housing for a fluid end assembly according to claim 1 wherein said first obtuse angle measures about 125° and said second obtuse angle measures about 115°.

5. A fluid end assembly, comprising: a pump housing with: a plunger bore being oriented along a first centerline and having a closed inner end and an open outer end; a suction passage intersecting said plunger bore and being oriented along a second centerline that is coplanar with said first centerline, said suction passage intersecting said first centerline at a first reference point so as to define a first obtuse angle; a discharge passage intersecting both said plunger bore and said suction passage, said discharge passage being oriented along a third centerline that is coplanar with said second centerline and said first centerline and that intersects said first centerline at a second reference point that is closer to said open outer end than said first reference point so as to define a second obtuse angle; an outlet passage intersecting said discharge passage substantially at right angles; a reciprocating plunger being located in said plunger bore; a suction valve being located in said suction passage; a discharge valve being located in said discharge passage; and, a fluid supply manifold secured to said pump housing and being in fluid communication with said suction passage.

6. The fluid end assembly according to claim 5 wherein said suction passage and said discharge passage are each provided with portions of reduced diameter that define a pair of decks for supporting, respectively, said suction-valve and said discharge valve within said suction passage and said discharge passage.

7. The fluid end assembly according to claim 5 wherein said discharge passage has a diameter that is greater than that of said suction passage so that, when servicing is required, the suction valve can be removed from said pump housing through said discharge passage.

8. The fluid end assembly according to claim 5 wherein said first obtuse angle measures about 125° and said second obtuse angle measures about 115°.

9. The fluid end assembly according to claim 5 further comprising a pony rod assembly attached by means of threaded fasteners to said plunger for connecting said plunger to a reciprocating part of the power end of a pump.

10. The fluid end assembly according to claim 5 wherein said suction valve includes: a first valve seat in said suction passage a piston having a head for engaging the top of valve seat and a stem extending downwardly from said head through said valve seat, said stem having a transverse aperture; a valve guide being positioned adjacent the bottom of said first valve seat and slidably receiving said stem; a valve keeper being fitted upon said stem such that said valve guide is disposed between said valve seat and said valve keeper; a keeper pin being slidably positioned within said transverse aperture in said stem and abutting said keeper; and, a compressed spring being positioned between said valve guide and said keeper so as to normally retain said head in flush engagement with the top of said valve seat thereby closing said suction valve.

11. The fluid end assembly according to claim 5 wherein said discharge valve includes a valve seat positioned within discharge passage; a piston releasably engaging said valve seat, said piston having a head for releasably engaging said valve seat and stem extending upwardly from said head and away from said valve seat; a valve guide mounted in said discharge passage adjacent said valve seat, said valve guide having a socket for receiving said stem and also having a plurality of apertures that traverse said valve guide and intersect said socket to provide pressure relief to said socket; and, a compressed spring being disposed between said valve guide and said head for normally retaining said head in flush engagement with the top of said valve seat and keeping said discharge valve closed.

12. A fluid end assembly, comprising: a pump housing with: a plunger bore having a closed inner end and an open outer end; a suction passage intersecting said plunger bore; a discharge passage intersecting both said plunger bore and said suction passage such that said discharge passage, said suction passage and said plunger bore radiate outwardly from their point of intersection to define a shape resembling a “Y”, said discharge passage having a diameter greater than that of said suction passage; an outlet passage intersecting said discharge passage substantially at right angles; a reciprocating plunger being located in said plunger bore; a suction valve being located in said suction passage; a discharge valve being located in said discharge passage; and, a fluid supply manifold secured to said pump housing and being in fluid communication with said suction passage.

13. The fluid end assembly according to claim 12 wherein said suction passage and said discharge passage are each provided with portions of reduced diameter that define a pair of decks for supporting, respectively, said suction valve and said discharge valve within said suction passage and said discharge passage.

14. The fluid end assembly according to claim 12 wherein said discharge passage has a diameter that is greater than that of said suction passage so that the suction valve can be removed from said pump housing through said discharge passage.

15. The fluid end assembly according to claim 12 further comprising a pony rod assembly bolted to said plunger.

16. The fluid end assembly according to claim 12 wherein said suction valve includes: a first valve seat positioned within said suction passage a piston having a head for engaging the top of said first valve seat and a stem extending downwardly from said head through said first valve seat, said stem having a transverse aperture; a valve guide being positioned adjacent the bottom of said first valve seat and slidably receiving said stem; a valve keeper being fitted upon said stem such that said valve guide is disposed between said first valve seat and said valve keeper; a keeper pin being slidably positioned within said transverse aperture in said stem and abutting said keeper; and, a compressed spring being positioned between said valve guide and said keeper so as to normally retain said head in flush engagement with the top of said first valve seat thereby closing said suction valve.

17. The fluid end assembly according to claim 16 wherein said discharge valve includes a second valve seat positioned within discharge passage; a piston releasably engaging said second valve seat, said piston having a head for releasably engaging said second valve seat and a stem extending upwardly from said head and away from said second valve seat; a valve guide mounted in said discharge passage adjacent said second valve seat, said valve guide having a socket for receiving said stem and also having a plurality of apertures that traverse said valve guide and intersect said socket to provide pressure relief to said socket; and, a compressed spring being disposed between said valve guide and said head for normally retaining said head in flush engagement with the top of said second valve seat and keeping said discharge valve closed.

18. A piston and valve seat for said suction valve described in claim 5 wherein: said valve seat is a tube with open, top and bottom surfaces; said piston has a head for engaging said top surface of said valve seat and a stem extending downwardly from said head through said valve seat, said stem having a transverse aperture; said valve has an engaged position wherein in said engaged position an abutment is positioned within said transverse aperture, and a compression spring is disposed between said head and said aperture, and a compression spring is disposed between said head and said aperture.

19. A discharge valve for the fluid end of claim 11, comprising: a valve seat positioned within a discharge passage; a piston releasably engaging said valve seat, said piston having a head for releasably engaging said valve seat and stem extending upwardly from said head and away from said valve seat; a valve guide mounted in said discharge passage adjacent said valve seat, said valve guide having a socket for receiving said stem and also having a plurality of apertures that traverse said valve guide and intersect said socket to provide pressure relief to said socket; and a compressed spring being disposed between said valve guide and said head for normally retaining said head in flush engagement with the top of said valve seat and keeping said discharge valve closed.