US20080138224A1 - Fluid end - Google Patents

Abstract

A fluid end for a high-pressure pump including a unitary body with a plurality of horizontal passages each for receiving a reciprocating plunger at one of its ends and a pressure relief valve at the other of its ends. The body is provided with a corresponding number of vertical passages each of which intersect one of the horizontal passages and contains a suction valve at its bottom and a discharge valve at its top. A suction manifold is hingedly attached to the bottom of body to provide a flow of fluid into the body via the suction valves. A discharge passage intersects the vertical passages and receives fluid pressurized by the plungers via discharge valves and ports such from the fluid end.

Description

• This application is a divisional of our pending application Ser. No. 10/173/837 filed on Jun. 19, 2002.
FIELD OF THE INVENTION
• The present invention relates generally to pumps having pumping chamber pressure responsive fluid distributors.
BACKGROUND OF THE INVENTION
• It is difficult to produce oil and gas 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 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.
• 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 within the body of which reciprocating plungers place fluids under pressure and valves control fluid flow to and from the plungers. The body of a fluid end is an aggregate of metal blocks releasably fastened to provide access to internal components for servicing. Unfortunately, the joints between the blocks 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. Thus, it is not unusual for the bodies of fluid ends to fail under load, cutting short their useful lives.
• Installing and servicing conventional fluid ends is difficult since their parts often weigh hundreds of pounds. A hoist is often required to lift and position the various portions of a fluid end body and, at this point in time, these portions are not typically provided with attachment features for hooks, chains or cables. Equally difficult is moving a suction manifold into place beneath a fluid end body since its awkward shape and great weight usually requires numerous hands for proper positioning. A need, therefore, exists for a fluid end of great strength and whose principal parts users can easily move.
SUMMARY OF THE INVENTION
• In light of the problems associated with conventional oilfield pumping equipment, it is a principal object of the present invention to provide a fluid end of great strength, durability and fatigue resistance. Such a fluid end features a “mono-block” design wherein its body is produced from a single piece of metal. Passages within the body retain reciprocating plungers and valves that pressurize fluids and control their flow through the fluid end. Since the body does not require seals between its constituent parts, it is not particularly susceptible to internal corrosion, fluid leaks and metal fatigue during normal use.
• It is another object of the invention to provide a fluid end of the type described with reinforced suction valve seat decks. Such seat decks are made possible by employing compact, stem-guided suction valves within the fluid end rather than conventional, and larger, wing-guided valves. The stem-guided valves fit within shallow pockets in the fluid end requiring less material be removed from the fluid end body than was possible in the past. Providing the seat decks with shallow bevels also adds strength by more evenly distributing loads imparted by the suction valves to the remainder to the fluid end body.
• It is an additional object of the invention to provide a fluid end with a body to which a hook, chain, cable, or other like lifting device can be attached so that it can be easily lifted and transported without the use of eyebolts that have a tendency to bend and break. Such a fluid end can, thus, be easily and safely moved about-a great benefit in an oilfield environment where pumps comprising fluid ends rarely remain in place for more than a few months
• It is a further object of the invention to provide a fluid end featuring hinges for the attachment of a suction manifold thereto. Such hinges permit easy access to the interior of the fluid end for while retaining the manifold in a clean and elevated state for easy repositioning and reattachment. With hinge elements of the sort described, servicing of suction valves within a fluid end can be a one-man job.
• It is an object of the invention to provide improved elements and arrangements thereof in a fluid end for the purposes described which is relatively inexpensive to manufacture and fully dependable in use.
• 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 drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
• The present invention may be more readily described with reference to the accompanying drawings, in which:
• FIG. 1 is a cross-sectional view of a fluid end in accordance with the present invention.
• FIG. 2 is a top view of the body forming a principal part of the fluid end ofFIG. 1.
• FIG. 3 is a front view of the fluid end body.
• FIG. 4 is a cross-sectional view taken along line4-4 ofFIG. 3.
• FIG. 5 is a perspective view of the fluid end body shown being lifted by a pair of chains.
• Similar reference characters denote corresponding features consistently throughout the accompanying drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
• Referring now to the FIGS., a fluid end in accordance with the present invention is shown at10.Fluid end10 includes abody12 with a plurality ofhorizontal passages14 each for receiving a reciprocating plunger16 at one of its ends and apressure relief valve18 at the other of its ends.Body12 is provided with a corresponding number ofvertical passages20 each of which intersect one of thehorizontal passages14 and contains asuction valve22 at its bottom and adischarge valve24 at its top. Asuction manifold26 is hingedly attached to the bottom ofbody12 so as to provide a flow of fluid intobody12 viasuction valves22. Adischarge passage28 intersectsvertical passages20 and receives fluid pressurized by plungers16 viadischarge valves24 and ports such fromfluid end10.
• Body12 is formed from a high alloy steel forging for maximum strength. Preferably, the forging has a cross-sectional configuration somewhat resembling the letter “H”. Thecrosspiece30 ofbody12 containshorizontal passages14 whereas theupright member32 containsvertical passages20.Upright member34 serves as a flange for mountingfluid end10 to the power end of a pump (not shown). It is anticipated that the power end would be conventional in construction with a crankshaft, connecting rods and other parts required to drive plungers16 back and forth inpassages14.
• Horizontal passages14 pass fully throughbody12 from its front to its back. At their front ends,passages14 are shaped to receivepacking elements36 for providing a fluid-tight seal around plungers16. At their rear ends,passages14 are threaded as at38 to receive thesuction nuts40 ofpressure relief valves18 as will be described further below.
• Vertical passages20 pass fully throughupright member32 from top to bottom. As shown, each of thevertical passages20 has an area of reduced diameter extending upwardly from the bottom ofupright member32 to a point about half of the way to its associatedhorizontal passage14. The top of each of these areas of reduced diameter defines adeck42 upon which asuction valve seat44 rests. Similarly, eachvertical passage20 has an area of reduced diameter extending between the bottom ofpassage28 and the top ofpassage14 that defines adeck46 upon which a discharge valve seat48 rests. The bottoms ofdecks42 and46 slope upwardly at an angle of approximately 30°. Such a slope is believed to allowdecks42 and46 to transfer forces imparted byvalve seats44 and48 evenly tobody12 thereby reducing the likelihood of fatigue induced cracks forming inbody12.
• Body12 is provided with a pair of liftingeyes50 so that it can be easily hoisted and transported. Liftingeyes50 are made by drilling a pair ofbores52 into the top ofupright member32 between the outer andcenter passages20 and then drilling a pair ofbores54 into the front ofupright member32 so as to intersect withbores52.Hooks56 at the end ofchains58 may be used to grasp the pair ofpins60 formed at the tops ofeyes50 made in this manner. So that thebody12 can be lifted without tipping, pins60 can be located above the center of gravity ofbody12 by milling a pair ofdeep recesses62 into the front ofupright member32 that intersect bores54 and inset pins60.
• Discharge passage28 extends throughupright member32 from one of its ends to the other. Threaded bores64 in the ends ofbody12 surroundingpassages28 permit conduits (not shown) to be securely connected tobody12 to carry pressurized fluids away fromfluid end10 for use in conducting a frac job or otherwise.
• The top and bottom portions ofupright member34 are provided with principal openings as at66 that permit the passage of threaded fasteners for joiningfluid end10 to the power end of a pump.Secondary openings68 in the top portion ofupright member34 and beneathprincipal openings66 permit any liquids that may fall atopbody12 to drain therefrom.
• Apivot pin70 is secured to each of the opposed, bottom ends ofupright member32 closely adjacent the front thereof. Eachpin70 is an Allen Head Bolt that is threadably fastened tobody12 or is an equivalent. Retaining rings72, secured to the opposed ends of the manifold mounting plate74, are suspended frompins70 at thebroken line position76 shown inFIG. 1 when themanifold mounting bolts78 are removed. A lever arm-receivingsocket80 is secured to manifold mounting plate74 to permitsuction manifold26 to be raised and lowered in a controlled fashion.
• Extending downwardly from manifold mounting plate74 are three,fluid inlet ports82 that receive and partially surroundsuction valves22.Suction manifold26 is suspended fromports82 and placed by them in fluid communication withsuction valves22. The opposed ends ofmanifold26 are open and connected to a fluid source whenfluid end10 is operated.Access openings84 are provided inmanifold26 adjacent each of thesuction valves22 so thatsuction valves22 can be easily examined and serviced. Each of theopenings84 is provided with aperipheral flange86 for receiving and supporting a close-fittingplug88. Threadedfasteners90 about each plug88 releasably secure such tomanifold26. Ahexagonal fitting92 at the center of each plug88 permits each plug88 to be rotated and rapidly removed from itsopening84.
• Eachsuction valve22 has avalve seat44 and a piston94 movably joined tovalve seat44. Piston94 has a head96 for engaging thetop valve seat44 and a stem98 extending downwardly from head96 throughvalve seat44. A valve guide100 is positioned adjacent the bottom ofvalve seat44 and slidably receives stem98. Avalve keeper102 is fitted upon stem98 such that valve guide100 is disposed betweenvalve seat44 andkeeper102. Akeeper pin104 is slidably positioned within atransverse aperture106 in stem98 and abuts the bottom ofkeeper102. Acompressed spring108 is positioned between, and exerts opposing forces upon, valve guide100 andkeeper102 so as to normally retain head96 in engagement with the top ofvalve seat44. The keeper pin has aperipheral groove107 around the keeper pin at about its midway point. The stem98 has adjacent the end opposite the head96, a roll pin aperture below the keeper pintransverse aperture106. the roll pin aperture is substantially at a right angle to thekeeper pin aperture106 and intersects the bottom thereof. Aroll pin105 is in the roll pin aperture to and passes through theperipheral groove107 to lock the keeper pin in place. Generally the keeper pin is larger than theroll pin105.
• Eachdischarge valve24 includes a valve seat48 and a piston110 for engaging valve seat48. Piston110 has a stein112 that extends upwardly from a head114 away from valve.

Claims (9)

1. A piston and valve seat of a suction valve comprising:

said valve seat forming a tube with open, top and bottom surfaces;

a piston having 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 at a lower end of said stem; and wherein

said valve seat and piston have an installed position where in said installed positioned said valve seat and piston are in a body of a fluid end.

2. The piston and valve seat of the suction valve ofclaim 1, wherein said fluid end is part of a high pressure pump.

3. The piston and valve seat of the suction valve ofclaim 2 wherein the fluid end of the high pressure pump is a forged metal mono-block.

4. The piston and valve seat of the suction valve ofclaim 3 wherein the high pressure pump is an oil field pump.

5. A high pressure pump piston for mating with a valve seat said pump piston comprising:

a stem having an end opposite a head;

a keeper pin transverse aperture and a lock pin aperture adjacent said end, said lock pin aperture at a right angle to said keeper pin aperture and said lock pin aperture intersects a bottom portion of the keeper pin aperture and opens into said keeper pin aperture, said lock pin aperture being positioned relative to said keeper pin aperture so when a keeper pin is in place in the keeper pin aperture and a lock pin is in place in the lock pin aperture the lock pin and keeper pin interface with one another.

6. The high pressure pump piston ofclaim 5 wherein the keeper pin aperture is larger than the lock pin aperture.

7. The high pressure pump piston ofclaim 5 wherein the piston is in a high pressure pump.

8. The high pressure pump piston ofclaim 7 wherein the fluid end of the high pressure pump is a forged metal mono-block.

9. The high pressure pump piston ofclaim 8 wherein the high pressure pump is an oil field pump.

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