Patent Application
20080152523
The present disclosure generally relates to high-pressure positive displacement pumps and in particular, pumps having a power end driving a reciprocating plunger within a fluid end.
Oil, natural gas, and other hydrocarbons are obtained by drilling wells into the earth and forcing them to the surface for collection. 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 where it enters a reservoir rock and cracks or fractures it. Proppants are carried in a suspension by the pumped fluid into the fractures. When the pressure is released, the fractures partially close on the proppants, leaving channels for oil and gas to flow. Specialized pumps are used to develop the pressures necessary to complete a hydraulic fracturing procedure or “frac job.”
Specialized pumps are also used in other drilling pump applications. For instance, during drilling of the well hole into the earth, specialized pumps are used to flush out the hole. Flush out is important to remove debris, such as rock chips ground out by the drill bit during drilling.
These specialized pumps are usually provided with fluid ends having reciprocating plungers or pistons that place fluids under pressure and valves that control fluid flow to and from the plungers. The body of a fluid end can be a metal forging of steel, having a “Y-type” configuration.
Y-type fluid ends have been developed in an effort to reduce the number of failures of fluid ends. It is 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 degrees to about 120 degrees. A typical Y-type fluid end is disclosed in U.S. Patent Application Publication No. US 2004/0234404, now abandoned, which is incorporated herein by reference.
Y-type fluid ends require periodic replacement due to the loads placed on the portions of the end such as the suction deck. The valves also have to be frequently replaced.
One aspect of the invention provides a fluid end assembly having a Y-type configuration with an easily accessible suction valve and discharge valve that are capable of replacement without disassembly of piping connected to the pump.
Another aspect of our invention provides a fluid end assembly with a removable and replaceable suction module. The suction module is removably attached to a first section of the fluid end. The first section to which the suction module is attached, has a discharge passage, pumping chamber, plunger bore, and a portion of the suction passage.
Another aspect of the invention provides a fluid end assembly that features suction and discharge valves that have valve seats and pistons of the same size so that they are interchangeable.
Briefly, the fluid end assembly of the present disclosure receives a fluid from a fluid supply manifold and supplies the fluid to an outlet manifold. The assembly has a first section. A plunger bore, extending into the first section, is oriented along a first centerline. The plunger bore is configured for receiving a reciprocating plunger.
A discharge passage in the first section intersects the plunger bore. The discharge passage is oriented along a second centerline. In the first section, a suction passage intersects the plunger bore. The suction passage is oriented along a third center line. The centerlines intersect to form a “Y” configuration.
A suction module forms a second section of the assembly. The suction module has an inlet which opens into a suction port. The port intersects a portion of the suction passage in the module. The suction port is oriented along a fourth center line. The fourth centerline is coplanar and transverse to said second centerline. The suction module is removably attached to the first section of the assembly.
The foregoing and other features and advantages of the present invention will become readily apparent upon further review of the following detailed description of the described embodiment and the accompanying drawings.
a-7b are cross section views of the block shown in
Referring now to
Portion 32 of the housing forms plunger section 32. Plunger section 32 has a bore 14, within which a plunger (not shown) reciprocates. Plunger bore 14 is provided within pump housing portion 32 At one end, plunger bore 14 terminates in a pumping chamber 18.
Housing portion 40 forms discharge section 40. A discharge passage 22 is formed in discharge section 40. Discharge passage 22 intersects plunger bore 14.
Housing portion 38a forms section 38a of the suction section formed by sections 38a, 38b. Portion 38a has portion 20a of a suction passage.
Housing portion 38b forms section 38b of the suction section. The suction section 38b can also be considered a suction module. Portion 38b has portion 20b of the suction passage 20a, 20b. Suction passage 20a, 20b intersects plunger bore 14.
The resulting Y-shaped configuration offered by the intersections of plunger bore 14 suction passage 20a, 20b, and discharge passage 22 reduces stresses within pump housing 12, 38b during use and minimizes the likelihood of the fluid end assembly failing over time.
Discharge passage 22 is formed in part by a counter bore 22a having a reduced diameter. Counter bore 22a extends from said plunger chamber 18 to discharge deck 52. Discharge deck 52 slopes at an angle of approximately 30°. A discharge port 30 in the discharge section 40 is in fluid communication with discharge passage 22 and in fluid communication with fluid discharge manifold 284. Fluid discharge manifold 284 may be connected to one or more conduits (not shown) to carry pressurized fluid from the discharge port 30 to perform work.
The plunger section 32 is of reduced length. The length at the discharge side is a length 32a. The length at the suction side is a length 32b. The plunger section 32 is adapted for attachment to the power end 34 of a high-pressure pump by a plurality of rods 36.
Suction module 38b contains a suction port 208 in fluid communication with suction passage 20b. Suction port 208 and suction passage 20b intersect to form suction valve chamber 20b′. Inlet 290 forms an opening into suction port 208. Counter bore 290a forms a portion of the suction port 208 having a reduced diameter. Counter bore 290a extends from said inlet 290 to suction deck 48. The suction deck 48 forms a 90 degree ledge. A 90 degree ledge allows for interchangeability with many existing valve seats. Although not shown the suction deck could be configured to slope outwardly at an angle of approximately 30 degrees. Suction module inlet 290 is along a fourth centerline D, that is coplanar with and transverse to suction passage 20a, 20b and centerline C. A fluid supply manifold 28 is located at inlet 290. As shown in
The fasteners 204, 206 or 207 join face 301 of module 38b to a face 302 of suction section 38a. The faces 301, 302 are joined to align suction passage section 20b with suction passage section 20a. To seal the faces 301, 302 and suction passage sections 20a, 20b to one another, alternative types of seals can be used. In
In
Suction valve 24 is within suction module 38b and interfaces fluid supply manifold 28 with suction passage 20a, 20b. The valve 24 includes valve seat 50 and a piston 56 configured to interface with valve seat 50. Piston 56 has a head 66 for engaging valve seat 50 and a stem 68 extending from the head 66. A valve guide 70, positioned along centerline D, has a socket 286 that slidably receives stem 68. At least one aperture 288 traverses suction valve guide 70 and intersect socket 286 to provide pressure relief to socket 286. A compressed spring 78 is positioned between, and exerts opposing forces upon, valve guide 70 and the suction valve head 66 so as to normally retain head 66 in flush engagement with valve seat 50 thus closing suction valve 24. The forces imparted by the valve seat 50 to the suction module 38b would be more evenly distributed by the use of a 30 degree angular slope of the suction deck 48. This would reduce the likelihood that fatigue-induced cracks will form in suction module 202. Valve guide 70 has a suction valve cover portion 70′ formed integrally from annular flange 70′ of the suction valve guide 70. The cover portion 70′ helps retain guide 70 in module 38b. The valve guide 70 is retained in the module 38b by way of nuts and bolts 209, valve ring 210, and cover lock 211. The suction valve 24 may be removed by removing the suction valve ring 210 and lock 211. Once the ring 210 and lock 211 are removed, the suction valve 24 may be pulled from the suction module 38b. This configuration allows removal of suction valve 24 from chamber 20b′ through single opening 203, without removal of the suction module 38b or the fluid supply manifold 28.
Discharge valve 26, disposed in discharge section 40, includes valve seat 54 and a piston 80 for engaging valve seat 54. Piston 80 has a stem 82 that extends from a head 84 away from valve seat 54 and into a socket 86 in a discharge valve guide 88. At least one aperture 92 traverses guide 88 and intersects socket 86 to provide pressure relief to valve guide 88. 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. Valve seat 54 rests on discharge deck 52. Discharge deck 52 forms a ledge of 90 degrees to allow for interchangeability with many existing valve seats. One could configure the deck to slope at an angle of approximately 30°. This slope would allow deck 52 to transfer forces impacted by valve seat 54 evenly to discharge section 40, thus reducing the likelihood of fatigue-induced cracks forming in housing 12. Valve guide 88 has a cover or closure portion formed integrally from annular flange 88′ of valve guide 88. The cover portion 88′ supports guide 88 and fills and seals an opening 300 which leads to hollow chamber 30a in which the discharge valve 26 is disposed. The cover portion 88′ is retained in section 40 by way of nuts and bolts 214, valve ring 215 and cover lock 216. The discharge valve 26 may be removed by removing valve ring 215 and cover lock 216. Once the valve ring 215 and cover lock 216. are removed, the discharge valve 26 may be pulled from the chamber 30a through opening 300. This configuration allows removal of the discharge valve 26 through a single opening.
Should valves 24 and 26, ever require servicing, such are easy to repair or replace with ordinary tools and without major disassembly of fluid end assembly 10. The pistons and seals are the same size on both the suction and discharge side and are thus interchangeable.
Valves 24 and 26 permit fluid pressurized by the plunger (not shown) to move in only one direction from manifold 28 to outlet passage 30. Fluid moves by way of a reciprocating motion of the plunger in plunger bore 14, During the suction stroke of the plunger, fluid is drawn into plunger chamber 18 from suction passage 20a, 20b. During the pressure stroke of the plunger, fluid is pushed from the chamber 18 through discharge passage 22 and out port 30.
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.
