CN216008879U - Gland, hydraulic end and plunger pump - Google Patents

Abstract

A gland, fluid end and plunger pump are provided. The gland includes: a body, the body being cylindrical, the body including a first end, a second end, and a side connecting the first end and the second end; a primary flow passage extending along an axis of the body; a plurality of secondary runners, each secondary runner communicating with the primary runner; a first opening at the first end and in communication with the primary flow passage; and the secondary flow passage is communicated with at least one of the second openings so as to simplify the structure of the hydraulic end and provide large-discharge output.

Description

Gland, hydraulic end and plunger pump

Technical Field

The embodiment of the utility model provides a gland, hydraulic end and plunger pump are related to.

Background

At present, fracturing construction in the oil and gas field exploitation process is a main yield increasing mode, and a plunger pump is main equipment for pumping fracturing medium in yield increasing operation. In other words, throughout the entire flow of oil and gas production, whatever process is required to deliver the medium to the well at a particular pressure, needs to be accomplished by the plunger pump.

Disclosure of Invention

An embodiment of the utility model provides a gland, fluid end and plunger pump to simplify the structure of fluid end, provide big discharge output.

An embodiment of the utility model provides a gland, include: a body, the body being cylindrical, the body including a first end, a second end, and a side connecting the first end and the second end; a primary flow passage extending along an axis of the body; a plurality of secondary runners, each secondary runner communicating with the primary runner; a first opening at the first end and in communication with the primary flow passage; and a plurality of second openings located on the side surface of the body, wherein the secondary flow passage is communicated with at least one of the plurality of second openings.

According to the utility model discloses a gland, the sprue is located the body on the axis, the sprue is in do not run through on the axis of body the body.

According to the utility model discloses a gland, the aperture of sprue is greater than the aperture of vice runner.

According to the utility model discloses a gland, a plurality of second openings are in the upwards evenly distributed of circumference of body.

According to the utility model discloses a gland, vice runner for the mainstream canal slope sets up.

According to the utility model discloses a gland is provided, the scope of the acute angle between the central line of vice runner and the central line of sprue is in 20-80 degrees.

According to the utility model discloses a gland, vice runner reaches the body the distance of axis is followed first end is to the direction of second end is crescent.

According to the utility model discloses a gland, gland still include the earial drainage passageway and are located the first earial drainage mouth and the second earial drainage mouth at the both ends of earial drainage passageway, wherein, first earial drainage mouth is located the body the side, the second earial drainage mouth is located the body the terminal surface of second end.

According to the utility model discloses a gland that embodiment provided, the earial drainage passageway with the mainstream canal does not communicate, and with side's fluid channel does not communicate.

According to the utility model discloses a gland, first earial drainage mouth is located the side is close to one side of the terminal surface of first end.

According to the utility model discloses a gland, gland still include the valve seat groove, the valve seat trench in first end, and with the sprue intercommunication, and the valve seat groove is deviating from one side of first end has the tool withdrawal groove.

According to the utility model discloses a gland, gland still include first sealing position and second sealing position, first sealing position is configured to set up first sealing washer, second sealing position is configured to set up the second sealing washer, first sealing position with second sealing position all is located the side, first earial drainage mouth is located first sealing position with between the second sealing position.

According to the utility model discloses a gland, gland still include first seal groove and second seal groove, first seal groove is configured to hold first sealing washer, the second seal groove is configured to hold the second sealing washer, first seal groove with the second seal groove all is located the side, first earial drainage mouth is located first seal groove with between the second seal groove.

According to the utility model discloses a gland, gland are still including drawing the hole, draw the hole site in the body the second end, draw the hole with the second outlet does not communicate.

According to the utility model discloses a gland, draw the hole site and be located the body on the axis.

The embodiment of the utility model provides a still provide a hydraulic end, including above-mentioned arbitrary gland.

According to the utility model discloses a fluid end, fluid end still includes that: the valve box comprises an inner cavity, and the inner cavity comprises a low-pressure cavity, an alternating cavity and a high-pressure cavity; the gland is located the low pressure chamber, the inner chamber of valve box is the type of falling T structure, the alternating chamber with the low pressure chamber is followed the extending direction of the first axis of inner chamber sets up, the alternating chamber with the high pressure chamber is followed the extending direction of the second axis of inner chamber sets up, first axis with the second axis is crossing.

According to the utility model discloses a fluid end that embodiment provided, the valve box has the last liquid hole, go up the liquid hole with the high pressure chamber is in the setting of staggering on the extending direction of first axis.

According to the utility model discloses a fluid end, fluid end still include first valve module, first valve module is configured to open with the intercommunication the low pressure chamber with alternating chamber or be configured to close with separating the low pressure chamber with alternating chamber, first valve module includes spring bracket, spring bracket is hollow out construction, and with the valve case carries on spacingly through the inclined plane.

According to the utility model discloses a fluid end that embodiment provided, the intersection of inner chamber includes first sub-chamber and second sub-chamber, first sub-chamber with the second sub-chamber is followed the extending direction of second axis sets up, the second sub-chamber than first sub-chamber is closer to the edge of inner chamber the part that first axis extends, the second sub-chamber is in the maximum dimension in the extending direction of second axis is greater than first sub-chamber is in the maximum dimension in the extending direction of second axis, the second sub-chamber is in size in the extending direction of first axis is from keeping away from the position of first axis is to being close to gradually increase in the direction of the position of first axis.

According to the utility model discloses a fluid end that embodiment provided, the valve box is corresponding first sub-chamber with the position of the sub-chamber of second is equipped with the lag.

According to the utility model discloses a fluid end, fluid end still include the second valve assembly, the second valve assembly is configured to open with the intercommunication the alternating chamber with the high pressure chamber or be configured to close with separating the alternating chamber with the high pressure chamber, the second valve assembly with the second sub-chamber is located the relative both sides of first sub-chamber.

The embodiment of the utility model provides a plunger pump is still provided, including above-mentioned arbitrary fluid end.

Drawings

In order to illustrate the technical solutions of the embodiments of the present invention more clearly, the drawings of the embodiments will be briefly described below, and it is obvious that the drawings in the following description only relate to some embodiments of the present invention, and are not intended to limit the present invention.

Fig. 1A is a sectional view of a plunger pump.

FIG. 1B is a schematic view of the fluid end of the plunger pump shown in FIG. 1A.

FIG. 1C is a schematic view of a valve box in the fluid end shown in FIG. 1B.

Fig. 2 is a cross-sectional view of a gland according to an embodiment of the present invention.

Fig. 3 is a perspective view of a pressing cover according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention.

Fig. 5 is a front view and a side view of a spring support in a hydraulic end according to an embodiment of the present invention.

Fig. 6 is a perspective view of another gland according to an embodiment of the present invention.

Fig. 7 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention.

Fig. 8 is a cross-sectional view of a valve box in a hydraulic end according to an embodiment of the present invention.

Fig. 9 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention.

Fig. 10 is a schematic diagram of a junction of inner chambers of a valve box in a hydraulic end according to an embodiment of the present invention.

Fig. 11 is a schematic view of the intersection of the inner chambers of the valve boxes in another fluid end according to an embodiment of the present invention.

Fig. 12 is a schematic diagram of a second valve assembly in a fluid end according to an embodiment of the present invention.

Fig. 13 is a schematic diagram of a valve box on a discharge side of a hydraulic end according to an embodiment of the present invention.

Fig. 14 is a schematic view of a sealing structure on a discharge side of a fluid end according to an embodiment of the present invention.

Fig. 15 is a schematic view of a valve housing on the suction side of a hydraulic end according to an embodiment of the present invention.

Fig. 16 is a schematic view of a sealing structure on the suction side of a hydraulic end according to an embodiment of the present invention.

Detailed Description

In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the drawings of the embodiments of the present invention are combined below to clearly and completely describe the technical solution of the embodiments of the present invention. It is to be understood that the embodiments described are only some of the embodiments of the present invention, and not all of them. All other embodiments, which can be obtained by a person skilled in the art without any inventive work based on the described embodiments of the present invention, belong to the protection scope of the present invention.

Unless defined otherwise, technical or scientific terms used herein shall have the ordinary meaning as understood by those of ordinary skill in the art to which the invention belongs. The use of "first," "second," and similar terms in the description herein do not denote any order, quantity, or importance, but rather the terms are used to distinguish one element from another. Likewise, the word "comprising" or "comprises", and the like, means that the element or item listed before the word covers the element or item listed after the word and its equivalents, but does not exclude other elements or items. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships may also be changed accordingly.

The plunger pump is used as one of key devices for fracturing construction, and mainly has the main function of converting fracturing fluid with certain viscosity under normal pressure into high-pressure and high-flow fracturing fluid to be injected into a stratum, and the performance of the fracturing fluid directly influences the technical level of fracturing construction operation of an oil-gas field. At present, the structure of fracturing pumps at home and abroad generally adopts a reciprocating horizontal multi-cylinder plunger pump, such as a three-cylinder plunger pump and a five-cylinder plunger pump, and the fracturing pump is generally composed of a hydraulic end and a power end. The hydraulic end is used for converting mechanical energy into pressure energy of the working fluid. The power end is used for transmitting the kinetic energy of the prime mover to the hydraulic end through the speed reducing transmission system and the crank-link mechanism.

Fig. 1A is a sectional view of a plunger pump. FIG. 1B is a schematic view of the fluid end of the plunger pump shown in FIG. 1A. FIG. 1C is a schematic view of a valve box in the fluid end shown in FIG. 1B. As shown in fig. 1A, the plunger pump 003 includes a power end 002 and a fluid end 001. As shown in fig. 1A and 1B, the fluid end 001 mainly includes a valve housing 01, a plunger 02, a valve assembly 03, a valve assembly 04, a sealing member, a gland 05, and a gland 06. Fig. 1A also shows a yoke 07, a tie rod 08, a crosshead 09, a connecting rod 010, a case 011, and a crankshaft 012. As shown in fig. 1B, the fluid tip 001 further includes a valve seat 021, a spring 022, a suction gland 023, a suction gland 024, a spring 025, a weep hole 026, a packing assembly 027 for sealing, and a packing gland 028. Fig. 1C shows a cruciform arrangement of the valve housing 01.

As shown in fig. 1A and 1B, the plunger pump operates as follows: the crankshaft 012 of the power end 002 rotates under the driving of the prime mover, so as to drive the connecting rod 010 and the crosshead 09 to horizontally reciprocate, and the crosshead 09 drives the plunger 02 to horizontally reciprocate in the valve box 01 through the pull rod 08. When the plunger 02 moves in a return stroke, the internal volume of the valve box 01 is gradually increased to form partial vacuum, the valve component 03 is opened at the moment, the valve component 04 is closed, the medium enters the inner cavity of the valve box 01, when the plunger 02 returns to the limit position, the inner cavity of the valve box 01 is filled with the medium, and the liquid suction action is finished. When the plunger 02 moves in a process, the volume in the valve box 01 is gradually reduced, the medium is squeezed, the pressure is increased, the valve assembly 04 is opened, the valve assembly 03 is closed, the medium enters the liquid discharge hole 026 under the action of the pressure, when the plunger 02 moves to the limit position, the medium accommodating space in the valve box 01 is minimum, and the liquid discharge action is finished. Because the plunger 02 is continuously reciprocated, the processes of liquid suction and liquid discharge are alternately carried out, and the high-pressure medium is continuously output.

Referring to fig. 1A to 1C, a valve box of a general hydraulic end is a cross-shaped intersecting structure, as shown in fig. 1C, an inner cavity of the valve box 02 is divided into a low-pressure cavity 01A, an alternating cavity 01b and a high-pressure cavity 01C according to pressure, however, an intersecting line is just located in the alternating cavity 01b, and mechanical analysis shows that stress concentration at the intersecting line is obvious, and in addition, due to the action of an alternating load, fatigue cracks are easily generated at the intersecting line, so that the valve box 01 cracks and leaks water, the valve box is frequently replaced on site, replacement cost is high, and time and labor are consumed.

Along with the fracturing construction difficulty is higher and higher (the working pressure is higher), the single machine large discharge capacity also becomes the market emergency demand, and if the stress concentration effect at the intersection part cannot be effectively improved all the time, the service life of the valve box cannot be prolonged.

An embodiment of the utility model provides a valve box with T type inner chamber to promote the life of valve box, provide a gland in order to simplify the structure of hydraulic end, promote the performance of hydraulic end. The embodiment of the utility model provides a still provide the hydraulic end and the plunger pump that contain this gland and have the valve box of T type inner chamber.

The gland, the hydraulic end and the plunger pump provided by the embodiment of the utility model are introduced below.

Fig. 2 is a cross-sectional view of a gland according to an embodiment of the present invention. Fig. 3 is a perspective view of a pressing cover according to an embodiment of the present invention. Fig. 4 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention. Fig. 5 is a front view and a side view of a spring support in a hydraulic end according to an embodiment of the present invention. Fig. 5(a) is a front view of the spring holder. Fig. 5(b) is a side view of the spring holder. Fig. 6 is a perspective view of another gland according to an embodiment of the present invention. Fig. 7 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention. Fig. 8 is a cross-sectional view of a valve box in a hydraulic end according to an embodiment of the present invention. Fig. 9 is a cross-sectional view of a hydraulic end according to an embodiment of the present invention.

As shown in fig. 2, 3, 6 and 7, an embodiment of the present invention provides a gland 10, the gland 10 including: the main body 100, the main flow passage 1021, a plurality of sub-flow passages 1022, a first opening P1, and a plurality of second openings P2. As shown in fig. 2, 3, 6 and 7, the body 100 is cylindrical, and the body 100 includes a first end E1, a second end E2, and a side S0 connecting the first end E1 and the second end E2; the primary flow passage 1021 extends along an axis of the body 100; each secondary flow passage 1022 communicates with the primary flow passage 1021; the first opening P1 is located at the first end E1 and communicates with the main flow passage 1021; the plurality of second openings P2 are located on the side surface S0 of the body 100, and the secondary flow passage 1022 communicates with at least one of the plurality of second openings P2.

The embodiment of the utility model provides a gland 10 is favorable to the fluid circulation, simplifies the structure of hydraulic pressure end, and contains the plunger pump of this gland and can realize big discharge output.

Fig. 2 to 4, 7 and 9 show the gland 10a, and fig. 6 shows the gland 10 b.

For example, as shown in fig. 2 and 7, the primary flow passage 1021 is located on an axis a0 of the body 100, and the primary flow passage 1021 does not extend through the body 100 on the axis of the body 100. As shown in fig. 2 and 7, the left end of the main flow passage 1021 communicates with the first opening P1, and the right end communicates with the sub flow passage 1022. For example, the primary flow passage 1021 extends in the direction of extension of the axis a0 of the body 100.

For example, as shown in fig. 2 and 7, in order to facilitate the flow of fluid, the aperture of the primary channel 1021 is larger than the aperture of the secondary channel 1022.

For example, as shown in fig. 3 and 6, in order to achieve a large discharge amount stable output, the plurality of second openings P2 are evenly distributed in the circumferential direction of the body 100. With the second opening P2 on side S0, the aperture of the secondary flow passage 1022 and the size of the second opening P2 can be set larger to facilitate fluid passage through the gland. The embodiment of the present invention is described by taking as an example that the gland 10 includes four second openings P2 evenly distributed in the circumferential direction of the body 100.

For example, as shown in fig. 2 and 7, in order to improve the performance of the gland and extend the lifespan of the gland, the sub-flow passage 1022 is disposed obliquely with respect to the main flow passage 1021.

In some embodiments, the plurality of secondary runners 1022 are inclined in the same direction and to the same degree with respect to the primary runner 1021. As shown in fig. 2 and 7, the plurality of secondary runners 1022 are all inclined to the right and have the same angle with the primary runner 1021.

For example, as shown in fig. 2 and 7, the acute angle θ 1 between the center line L2 of the secondary flow channel 1022 and the center line L1 of the primary flow channel 1021 ranges from 20 to 80 degrees. The gland shown in fig. 2 and 7 is described by taking an example in which the center line L1 of the main flow channel 1021 coincides with the axis a0 of the main body 100.

For example, as shown in fig. 2 and 7, the distance from the secondary flow passage 1022 to the axis a0 of the body 100 gradually increases in a direction from the first end E1 to the second end E2. That is, as shown in fig. 2, the sub-flow passage 1022 is inclined toward the right. Of course, in other embodiments, the secondary flow passage 1022 may be inclined toward the left, in which case the distance from the secondary flow passage 1022 to the axis a0 of the body 100 gradually decreases from the first end E1 to the second end E2.

For example, as shown in fig. 3, 6 and 7, the gland 10 further includes a drain passage 1000, and a first drain port 1001 and a second drain port 1002 located at both ends of the drain passage 1000, the first drain port 1001 being located at the side surface S0 of the body 100, and the second drain port 1002 being located at the end surface S2 of the second end E2 of the body 100.

For example, as shown in fig. 2-4, the gland 10a further includes a first sealing position PS1 and a second sealing position PS2, the first sealing position PS1 configured to provide a first seal 1011S, the second sealing position PS2 configured to provide a second seal 1012S, and both the first sealing position PS1 and the second sealing position PS2 located on the side S0.

For example, as shown in fig. 2-4, the first vent 1001 is located between the first sealing position PS1 and the second sealing position PS 2.

For example, as shown in fig. 6, the gland 10b further includes a first seal groove 1011 and a second seal groove 1012, the first seal groove 1011 is configured to receive a first seal ring 1011S, the second seal groove 1012 is configured to receive a second seal ring 1012S, and both the first seal groove 1011 and the second seal groove 1012 are located at the side surface S0. The first seal groove 1011 and the first seal 1011s form a first seal SL1, and the second seal groove 1012 and the second seal 1012s form a second seal SL 2.

For example, as shown in fig. 6, a first vent 1001 is located between a first seal groove 1011 and a second seal groove 1012.

For example, the first seal groove 1011 and the second seal groove 1012 form the seal groove 101. The first seal 1011s and the second seal 1012s constitute a first seal structure 101 s.

For example, the bleed flow passage 1000 is configured to communicate fluid when the first sealing structure 101s at least partially fails.

For example, as shown in fig. 3, 6 and 7, the drain passage 1000 does not communicate with the primary passage 1021 and does not communicate with the secondary passage 1022.

For example, as shown in fig. 3, 6, and 7, the first drain 1001 is located on the side of the side surface S0 close to the end surface S1 of the first end E1.

For example, as shown in fig. 4, 7-9, the fluid end further includes a valve box 70. The valve box 70 includes an interior cavity 07. For example, as shown in fig. 8 and 9, the inner cavity 07 of the valve housing 70 includes a low pressure chamber 07a, an alternating chamber 07b, and a high pressure chamber 07 c.

For example, in embodiments of the present invention, the pressure of the fluid in the high pressure chamber 07c is greater than the pressure of the fluid in the low pressure chamber 07a, and the pressure of the fluid in the alternating chamber 07b may be alternately changed.

As shown in fig. 7 and 9, the hydraulic end includes a press cap 20, and the press cap 20 is threadedly coupled to the valve housing 70.

As shown in fig. 7, one end of the drain passage 1000 is bored from the end surface S2 of the gland (second drain port 1002), and the other end is bored in the outer diameter of the gland (first drain port 1001). The first leakage port 1001 is arranged between two seals (a first seal SL1 and a second seal SL2), when the first seal SL1 fails, liquid leaks, the annular cavity between the valve box 70 and the gland 10 is filled with the liquid, the liquid flows to the gap between the gland 10 and the gland 20 along the leakage channel 1000, and when a certain amount of liquid is accumulated, the liquid flows out along the outer diameter (thread) or inner hole of the gland 20, at the moment, the liquid leakage is observed, which indicates that the first seal SL1 fails, so that an operator can judge the use condition of the first seal SL1 according to whether the liquid leakage exists at the position, and cannot timely react when the first seal SL1 fails, so that high-pressure liquid penetrates into the low-pressure liquid after the second seal SL2 fails, and the equipment is pressed and damaged.

For example, as shown in fig. 2 and 7, the gland 10 further includes a valve seat groove 1013, the valve seat groove 1013 is located at the first end E1 and communicates with the main flow passage 1021, and the valve seat groove 1013 has a relief groove 1013a at a side facing away from the first end E1 for reducing stress concentration.

For example, in order to facilitate the disassembly and assembly of the gland during maintenance, the gland 10 further includes a drawing hole 1003, the drawing hole 1003 is located at the second end E2 of the body 100, and the drawing hole 1003 is not communicated with the second drainage port 1002 and is not communicated with the drainage channel 1000. For example, the drawing hole 1003 is located on the axis of the body 100.

For example, as shown in fig. 2 to 4, 6 to 7, and 9, the gland 10 may be provided with flow passages (main flow passage 1021, sub flow passage 1022) and a drain passage 1000 inside, a drawing hole 1003 and a valve seat groove 1013 on an end surface, and a seal groove may be provided on an outer diameter of the gland 10. The low-pressure liquid flows through the inside of the flow passage and is formed by intersecting a main flow passage 1021 and auxiliary flow passages 1022, the axis of the main flow passage 1021 (the center line L1 of the main flow passage 1021) is overlapped with the axis of the gland 10, and the auxiliary flow passages 1022 are uniformly distributed in the circumferential direction of the gland; the bottom of the valve seat slot 1013 is a plane, the side is a conical surface, the root has a relief slot 1013a for reducing stress concentration, and the corresponding valve seat is also provided with a conical surface to match and fix.

For example, in some embodiments, as shown in fig. 2 and 3, the left side of the gland at the fluid end is not provided with a sealing groove, the sealing groove is arranged on the valve box, and the outer diameter of the gland 10 is in interference fit with the sealing element, so that the high-pressure fluid and the low-pressure fluid are prevented from being mixed. As shown in fig. 8 and 9, after the gland 10 is worn by the seal members (the first seal ring 1011s and the second seal ring 1012s), the gland can be replaced, and maintenance cost can be reduced. Note that, as shown in fig. 6, the seal groove 101 may be provided on the left side of the gland, and is not limited to the seal groove provided in the valve housing 70. Fig. 8 shows seal groove 1018 and seal groove 1019 in valve housing 70. As shown in fig. 7 and 8, a first seal 1011s is provided in the seal groove 1018, and a second seal 1012s is provided in the seal groove 1019.

The embodiment of the present invention provides a gland 10 including at least one of the following advantages.

(1) The end plug, the flow channel and the base are integrated, and multiple functions are integrated, so that the overall structure of the hydraulic end is more compact and simple, and the hydraulic end can be fixed and limited by using a common pressure cap in the hydraulic end.

(2) The gland uses as the base of disk seat, when the disk seat wearing and tearing need be changed, can be with its and gland whole change, need not use other instruments to pull out it again, avoids reducing maintenance efficiency, and maintenance time is very short when fracturing construction after all, adopts whole change can improve on-the-spot maintenance efficiency greatly.

(3) The built-in earial drainage passageway of gland, whether can be fast, direct judgement is sealed to become invalid, prevents to lead to the cluster pressure in time because of discovering, causes equipment damage, influences the fracturing construction.

(4) The hollow structure (runner) of gland makes the low pressure liquid circulation smooth and easy, and fracturing fluid all is sand inclusion fracturing fluid generally, and the risk that sand was blocked up can be reduced to a plurality of vice runners and the cooperation of large aperture sprue use.

The embodiment of the utility model provides a still provide a hydraulic end, including above-mentioned arbitrary gland 10.

The embodiment of the utility model provides a valve box inner chamber of hydraulic pressure end is T type structure, will run through the position and design into "horn mouth" form, alleviates the problem of the intersection line department stress concentration of inner chamber. The valve box 70 may be referred to as a T-type valve box.

For example, as shown in fig. 8 and 9, the gland 10 is located in the low pressure chamber 07a, the inner chamber 07 of the valve box 70 has an inverted T-shaped structure, the alternating chamber 07b and the low pressure chamber 07a are disposed along an extending direction of a first axis a1 of the inner chamber 07, the alternating chamber 07b and the high pressure chamber 07c are disposed along an extending direction of a second axis a2 of the inner chamber 07, and the first axis a1 intersects the second axis a 2. The embodiment of the present invention is described by taking the first axis a1 perpendicular to the second axis a2 as an example.

Fig. 8 shows a first axis a1 and a second axis a2 of the lumen 07. As shown in fig. 8, the inner chamber 07 includes a horizontal chamber 0701 and a vertical chamber 0702.

For example, as shown in fig. 8 and 9, the inner cavity of the valve housing 70 has a T-shaped structure, the inner cavity 07 is divided into a low pressure cavity 07a, an alternating cavity 07b and a high pressure cavity 07c according to the installation positions of the first valve assembly and the second valve assembly, and the intersection of the inner cavities 07 is designed in a form of a "bell mouth" and is smoothly transited, so that the stress concentration effect can be effectively improved.

The embodiment of the utility model provides a structure of the valve box of hydraulic end compares with the valve box of usual hydraulic end, has following characteristics.

1) The stress concentration effect of the inner cavity is obviously improved.

The lumen of the cross-shaped intersecting structure is shown in fig. 1C, and the intersecting position includes a position Pa, a position Pb, a position Pc, and a position Pd. Stress concentration points are arranged at the position Pc and the position Pd, stress concentration is very obvious from mechanical analysis, fatigue cracks are easy to be generated, and the valve box is cracked.

The embodiment of the utility model provides an there is not the right angle in the inner chamber of the valve box in the hydraulic end department of intersecting, and the transition rounding and rounding off of inner chamber department of intersecting has carried out optimal design in the position that produces stress concentration most easily, and the department of intersecting is the horn mouth shape, and no stress concentration point, the concentrated effect of analysis stress from mechanics has obvious improvement.

2) Simple structure, the leakproofness is strong.

The valve box in usual fluid end is split type structure, and packing chamber, suction chamber (low pressure chamber) and discharge chamber (high pressure chamber) need with the bolt tight to the main part of valve box on, this structure is comparatively miscellaneous, and needs multiple sealing member to seal, has increased many places in the intangible and has leaked. The sealing surface has high processing precision, more man-hours required for the sealing surface are more, the processing efficiency is lower, and finally the sealing can not be completely ensured.

The embodiment of the utility model provides a valve box in the hydraulic end is monolithic structure, and the sealing is tight, anti high pressure, and the sealing member of use is less and can not use the bolt, and simple structure is compact, and the risk of valve box thorn hourglass is lower.

3) The maintenance is convenient.

The axis of the plunger in usual fluid end is not the collineation with the axis of valve case, and the plunger can not draw out from the suction side, when the plunger damaged or need change packing package subassembly, need pull down whole fluid end, because the fluid end is heavier, can use the crane to assist during, greatly reduced maintenance efficiency, during the actual fracturing construction, the first side can not remain the long time and change the accessory. In some conventional hydraulic ports, the axis of the plunger is collinear with the axis of the horizontal chamber of the valve housing, but there are several inconveniences associated with maintaining the valve. For example, when the plunger or the packing package assembly is maintained, the diameter of the plunger is large, the plunger cannot be pulled out of the inner cavity of the valve box, the maintenance is performed after the whole hydraulic end is disassembled, and even if the diameter of the plunger is small, the plunger can be pulled out of the inner cavity of the valve box, the suction side needs to be disassembled, so that the maintenance can be performed.

The embodiment of the utility model provides a hydraulic end does not have the inconvenient problem of above-mentioned dimension guarantor, and the axis of plunger and the coincidence of the first axis (horizontal axis) of valve box, suction side are equipped with the pressure cap, and the axis of pressing the cap coincides with the axis of plunger, and the conventional operation according to the well site can when the dimension is protected.

For example, the most efficient conventional operations for well site servicing of a plunger or packing set assembly are: the method comprises the following steps of disassembling a pressure cap at a suction side, opening a horizontal cavity of a valve box, disassembling a hoop, disconnecting a hydraulic end from a power end, pulling out a plunger from the suction side along the axis of the horizontal cavity of the valve box by using a pulling tool, carrying out normal maintenance, recovering accessories by reverse operation according to the action after maintenance, and not disassembling the hydraulic end from a plunger pump in the whole maintenance process.

For example, as shown in fig. 4 and 7 to 9, the valve housing 70 has an upper fluid hole 700, and the upper fluid hole 700 and the high-pressure chamber 07c are arranged to be offset in the extending direction of the first axis a 1.

For example, as shown in fig. 4 and 9, the fluid end further includes a first valve assembly V1, the first valve assembly V1 being configured to open to communicate the low pressure chamber 07a and the alternating chamber 07b or to close to isolate the low pressure chamber 07a from the alternating chamber 07 b.

For example, as shown in fig. 4 and 9, the first valve assembly V1 includes a valve body 1a, a seal 1b (functioning as a seal), a valve seat 1c, a spring 1d, and a spring holder 1 e.

For example, as shown in fig. 4 and 9, the seal 1b is fitted into the valve body 1a, and when the first valve assembly V1 is opened, the valve body 1a fitted with the seal 1b is moved leftward, and the low pressure chamber 07a and the alternate chamber 07b communicate with each other.

As shown in fig. 5, the spring support 1e is a hollow structure, and includes a main body e1 and a hollow structure e0, and is limited with the valve box 70 by an inclined surface S01. Spring bracket 1e with hollow out construction e0 is favorable to the liquid circulation smooth and easy to carry on spacingly through inclined plane S01, prevent that spring bracket 1e from rocking in the horizontal intracavity of valve box 70, the horizontal chamber of corresponding valve box also is equipped with the inclined plane cooperation of inclined plane and spring bracket 1e, and spring bracket 1e passes through the inclined plane contact with valve box 70.

For example, as shown in fig. 9, the fluid end further includes a second valve assembly V2, the second valve assembly V2 being configured to open to communicate between the alternating chamber 07b and the high pressure chamber 07c or to close to isolate the alternating chamber 07b from the high pressure chamber 07 c.

For example, as shown in fig. 9, the second valve assembly V2 includes a valve body 2a, a seal 2b (functioning as a seal), a valve seat 2c, a spring 2d, and a seat 2 f.

For example, as shown in fig. 9, the seal 2b is fitted into the valve body 2a, and when the second valve assembly V2 is opened, the valve body 2a fitted with the seal 2b is moved upward, and the high-pressure chamber 07c and the alternating chamber 07b communicate with each other.

As shown in fig. 9, the second valve assembly V2 is adjacent the outlet orifice 7005 and is open to allow high pressure fluid flow during plunger travel; the first valve component V1 is close to the liquid feeding hole 700, and is opened during the return stroke of the plunger to circulate low-pressure liquid; the base 2f of the second valve unit V2 is directly fitted into the valve housing 70, and has a hardness greater than that of the valve housing 70, so that the valve housing 70 is prevented from being damaged during opening and closing (during slapping), and the service life of the valve housing 70 is prolonged.

For example, as shown in fig. 8, the valve housing 70 is formed in a flare shape at a intersection 7006 of the inner cavity 07 by machining, for example, but not limited thereto, the flare shape may be machined by boring.

For example, as shown in fig. 8 and 9, the intersection of inner cavity 07 comprises a first sub-cavity 071 and a second sub-cavity 072, the first sub-cavity 071 and the second sub-cavity 072 are arranged along the extension direction of second axis a2, the second sub-cavity 072 is closer to the portion of inner cavity 07 extending along first axis a1 (horizontal cavity) than the first sub-cavity 071, and in order to alleviate stress concentration, the maximum dimension h2 of the second sub-cavity 072 in the extension direction of second axis a2 is greater than the maximum dimension h1 of the first sub-cavity 071 in the extension direction of second axis a 2. The second valve assembly V2 is not disposed within the first sub-chamber 071 and the second sub-chamber 072. Second valve assembly V2 is located outside of first sub-chamber 071 and second sub-chamber 072. First sub-chamber 071 and second sub-chamber 072 may be cavities for fluid communication only.

For example, as shown in fig. 8 and 9, second valve assembly V2 and second sub-chamber 072 are located on opposite sides of first sub-chamber 071.

For example, as shown in fig. 8 and 9, to mitigate stress concentrations, the dimension D1 of the second subcavity 072 in the direction of extension of the first axis a1 gradually increases from a location distal to the first axis a1 to a location proximal to the first axis a 1.

For example, the portion of valve box 70 used to form second subchamber 072 is angled 30-80 degrees from first axis A1. For further example, the portion of valve box 70 used to form second subchamber 072 is angled 30-60 degrees from first axis a 1.

For example, as shown in fig. 9, the first sub-cavity 071 is a cylindrical cavity, but is not limited thereto. For example, as shown in fig. 2, the second sub-cavity 072 is a truncated cone shaped cavity, but is not limited thereto.

For example, as shown in fig. 9, valve box 70 is provided with a protective jacket 73 at a position corresponding to first sub-chamber 071 and second sub-chamber 072. A protective sleeve 73 is arranged at the bell mouth position of the inner cavity 07 of the valve box 70 to protect the inner cavity 07, and the service life of the valve box 70 is prolonged.

For example, as shown in fig. 9, the gland 10 is a rotary body structure, and is horizontally placed inside the valve box 70, the left side is in contact with the first valve assembly V1, the right side is in contact with the press cap 20, and the press cap 20 is screwed into the valve box 70.

For example, as shown in fig. 9, the fluid end includes a plunger 81. The plunger 81 is a rotary body, one end of the plunger 81 reciprocates in contact with the liquid in the valve housing 70, and the other end is connected to the power end of the plunger pump via a yoke 86. For example, as shown in fig. 9, the fluid end also includes a plunger side 70 c.

For example, as shown in fig. 8, the lumen 09 further includes a plunger region 07d, the plunger region 07d configured to position the plunger 81. The plunger area 07d, the alternating chamber 07b, and the low pressure chamber 07d are arranged in this order along the extending direction of the first axis a1 of the inner chamber 07.

For example, as shown in fig. 9, the fluid end further includes a packing set assembly 82, the packing set assembly 82 including a packing set 821, a spacer ring 822, and a compression ring 823.

For example, as shown in fig. 9, the packing set 821 includes three packing rings, but the number of packing rings is not limited to that shown in the figure and may be determined as needed. For example, the material of the packing ring includes, but is not limited to, rubber.

For example, as shown in fig. 9, a lubricating oil passage 7007 is provided on the plunger side of the valve housing for lubricating a packing set 821 (rubber) to make the reciprocating motion of the plunger 81 smoother; the plunger 81 is surrounded by a packing 821, and the packing 821 plays a sealing role to prevent liquid from leaking when the plunger 81 reciprocates.

For example, as shown in fig. 9, the inner wall of the packing set 821 is in interference fit with the plunger 81 to perform a sealing function; the plunger 81 reciprocates to rub against the inner wall of the packing 821 with forced lubrication to reduce friction.

For example, the plunger 81 has a drawing hole (bolt hole) at the front end thereof, and a drawing tool is provided, and when maintenance is performed, the clip 86 is removed, disconnected from the power end, and the plunger 81 is drawn out from the suction side 70a along the first axis a1 of the valve housing 70 by the drawing tool.

For example, as shown in fig. 9, the hydraulic end also includes a packing cap 83, the packing cap 83 configured to press against the packing assembly 82.

For example, the packing 821 is fixed by the packing cap 83, and the packing cap 83 is screwed to the valve housing 70. The packing gland 83 functions as: when the plunger 81 reciprocates, the packing 821 is prevented from moving axially, and the packing 821 is expanded by screwing and pressing, which is advantageous for sealing. Packing package 821's both ends are equipped with spacer ring 822 and clamping ring 823 respectively, and spacer ring 822 keeps apart packing package 821 and valve box 70, and clamping ring 823 keeps apart packing package 821 and packing pressure cap 83, and protection packing package 821 prolongs packing package 821's life. For example, the spacer ring 822 and the pressure ring 823 may be metal pieces.

For example, as shown in fig. 9, the fluid end further includes a packing sleeve 84 and a packing sleeve pressure cap 85, the plunger cavity 07d is configured to receive the plunger 81, the packing sleeve 84 is positioned between the packing assembly 82 and the valve housing 70, and the packing sleeve pressure cap 85 is configured to press the packing sleeve 84.

For example, as shown in FIG. 9, the packing set 84 is axially retained by a shoulder and packing set gland 85.

For example, at least one of the packing set 84 and the packing set gland 85 is welded to the valve housing 70.

For example, the packing set 84 has a hardness greater than the valve housing 70. Because the packing set 84 has a hardness higher than that of the valve housing 70, the packing set 84 is not damaged when the valve housing 70 is damaged, and therefore the packing set 84 and the valve housing 85 can be fixed by welding.

For example, as shown in FIG. 9, the outer diameter of the packing set 821 contacts the packing sleeve 84, and the inner diameter of the packing set 821 contacts the plunger 81; the front end of the packing sleeve 84 is provided with a sealing piece 7008, so that high-pressure liquid is prevented from entering a gap to cause liquid leakage and damage to a valve box; the packing set 84 is a wear-resistant member and is in interference fit with the valve housing 70, and the hardness of the packing set 84 is higher than that of the valve housing. The packing sleeve 84 is arranged to prevent the packing package 821 from being damaged due to friction, and the service life of the valve box is prolonged.

For example, the inner and outer diameters of the packing sleeve pressing cap 85 are both provided with threads, the outer threads of the packing sleeve pressing cap 85 are matched with the valve box 70, the inner threads of the packing sleeve pressing cap 85 are matched with the packing pressing cap 83, and the packing sleeve pressing cap 85 can be fixed with the valve box 70 through welding in order to prevent the packing sleeve pressing cap 85 from loosening when the plunger 81 reciprocates.

Fig. 9 also shows the discharge side 70b of the fluid end. The suction side 70a of the valve box 70 is provided with a liquid supply hole 700, and the discharge side 70b is provided with a discharge hole 7005. For example, the upper liquid hole 700 is connected with an upper water manifold, and low-pressure liquid flows inside; the discharge port 7005 is connected to the discharge flange, and a high-pressure liquid flows through the inside.

Fig. 9 also shows the body 77 of the valve box 70. The valve housing 70 includes a body 77 and an internal cavity 07.

For example, as shown in fig. 8 and 9, the valve housing 70 is provided with a suction-side screw 7001, a discharge-side screw 7002, and a plunger-side screw 7003. The pressure cap 20 is connected to the valve housing 70 by suction side threads 7001. The pressure cap 50 is connected to the valve housing 70 via the discharge side screw 7002. The packing set pressure cap 85 is connected to the valve housing 70 by the plunger-side threads 7003.

For example, the first valve assembly V1 and the second valve assembly V2 are both one-way valves. For example, as shown in FIG. 9, the first valve assembly V1 and the second valve assembly V2 may be interchanged. For example, the second valve assembly V2 is positioned vertically, the first valve assembly V1 is positioned horizontally, and the axial directions of the first valve assembly V1 and the second valve assembly V2 are perpendicular to each other.

As shown in fig. 4 and 9, with the first valve assembly V1, the valve seat 1c is disposed in the valve seat groove 1013 of the gland 10, and the left side of the gland 10 serves as a base of the valve seat 1c for fixing the valve seat 1 c. For example, the gland 10 is used in cooperation with the valve body 1a, the seal 1b, the spring 1d, and the spring holder 1e to form a check valve. For example, the axis of the first valve assembly V1 coincides with the axis of the gland 10. When the plunger returns, the valve body 1a is opened, and low-pressure liquid enters the valve box 70; during plunger travel, the valve body 1a closes, preventing low pressure fluid from entering the valve housing 70.

For example, referring to fig. 9, taking the fluid entering the fluid end as fracturing fluid as an example, the working principle of the fluid end is as follows.

During liquid suction, the plunger 81 returns (translates leftwards), the first valve assembly V1 is opened, the second valve assembly V2 is closed, and fracturing fluid flows into the alternating cavity 07b from the suction manifold through the upper fluid hole 700, the auxiliary fluid passage 1022 and the main fluid passage 1021 until the alternating cavity 07b is filled with the fracturing fluid, wherein the fluid in the inner cavity 07 is low-pressure fluid.

During discharge, the plunger 81 progresses (translates to the right), the first valve assembly V1 closes, the second valve assembly V2 opens, and the fracturing fluid flows from the alternating chamber 07b into the high pressure chamber 07c and is discharged through the discharge orifice 7005, wherein the fluid in the internal chamber 07 is high pressure fluid.

Fig. 10 is a schematic diagram of a junction of inner chambers of a valve box in a hydraulic end according to an embodiment of the present invention. Fig. 10(a) is a cross-sectional view of the XY plane of the inner chamber of the valve housing. Fig. 10(b) is a schematic view of the YZ plane of the inner cavity of the valve box. Fig. 11 is a schematic view of the intersection of the inner chambers of the valve boxes in another fluid end according to an embodiment of the present invention. Fig. 11(a) is a cross-sectional view of the XY plane of the inner cavity of the valve housing. Fig. 11(b) is a schematic diagram of the YZ plane of the inner cavity of the valve box.

Fig. 12 is a schematic diagram of a second valve assembly in a fluid end according to an embodiment of the present invention. As shown in fig. 12, the valve body 2a includes a boss a1 and a claw a2, the boss a1 has a function of limiting the spring 2d and preventing the spring 2d from moving radially, the boss a1 also has a function of limiting the opening height of the valve body 2a, and when the second valve assembly V2 is opened, the boss a1 of the valve body 2a is in rigid contact with the boss of the discharge gland 40, so that the uniform height of each opening is realized.

As shown in fig. 12, the inner hole of the base 2f is in clearance fit with the jaw a2, and plays a role in guiding the jaw a2 to prevent the valve body 2a from deflecting under the impact of high-pressure liquid; valve seat 2c and base 2f are split type structure, and the hardness of base 2f is higher than the hardness of base 2f, and when the purpose prevented that valve body 2a from slapping valve seat 2c, the inclined plane of valve seat 2c took place wearing and tearing, and it is relatively poor to avoid wearing and tearing valve seat 2c to cause the leakproofness, also avoids reducing the life of valve seat and valve body simultaneously.

The structure and function of the first valve assembly can be referred to the above description. Except that the boss of the valve body 1a is in rigid contact with the boss of the spring holder.

Fig. 13 is a schematic diagram of a valve box on a discharge side of a hydraulic end according to an embodiment of the present invention. Fig. 14 is a schematic view of a sealing structure on a discharge side of a fluid end according to an embodiment of the present invention. Fig. 15 is a schematic view of a valve housing on the suction side of a hydraulic end according to an embodiment of the present invention. Fig. 16 is a schematic view of a sealing structure on the suction side of a hydraulic end according to an embodiment of the present invention.

Fig. 12 shows a seal 1021, where the seal 1021 comprises a sealing ring with a sealing groove at the corresponding position of the base 2 f. As shown in fig. 12 and 13, a seal 1021 is provided to effect a seal between the second valve assembly V2 and the valve box 70.

Fig. 13 shows a seal groove 901 and fig. 14 shows a seal 902. A seal 902 is provided to effect a seal against the high pressure chamber of the inner chamber.

Fig. 15 shows seal groove 903 and fig. 16 shows seal 904. A seal 904 is provided to effect a seal against the low pressure chamber of the internal chamber.

The embodiment of the utility model provides a fluid end has following at least one's effect.

1) The stress concentration effect of the inner cavity is obviously improved.

The embodiment of the utility model provides an there is not the right angle in the inner chamber department of intersecting of the valve box of hydraulic pressure end, and the transition rounding and rounding off of inner chamber department of intersecting has carried out the shape design in the position that produces stress concentration most easily, and the department of intersecting is the horn mouth shape, and no stress concentration point, the concentrated effect of analysis stress has obvious improvement from mechanics.

2) Simple structure, the leakproofness is strong.

The embodiment of the utility model provides a valve box of hydraulic end is monolithic structure, and the sealing is tight, anti high pressure, and the sealing member of use is less and can not use the bolt, and simple structure is compact, and the risk of valve box thorn hourglass is lower.

3) The maintenance is convenient.

The embodiment of the utility model provides a hydraulic end, the axis of plunger and the coincidence of the first axis (horizontal axis) of valve box, the suction side has the pressure cap (the axis of pressing the cap coincides with the axis of plunger, presses the cap to dismantle), and the maintenance time according to the conventional operation in well site can.

The embodiment of the utility model provides a plunger pump is still provided, including above-mentioned arbitrary fluid end. Because the gland 10 is located on the suction side 70a of the fluid end, the gland 10 may also be referred to as a suction gland.

For example, the gland 10, fluid end containing the gland 10, and plunger pump may be used in an oil and gas field fracturing/cementing apparatus.

The above description is only for the specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present invention, and all should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims (23)

1. A gland, comprising:

a body, the body being cylindrical, the body including a first end, a second end, and a side connecting the first end and the second end;

a primary flow passage extending along an axis of the body;

a plurality of secondary runners, each secondary runner communicating with the primary runner;

a first opening at the first end and in communication with the primary flow passage; and

and the secondary flow passage is communicated with at least one of the second openings.

2. The gland of claim 1, wherein said primary flow passage is located on said axis of said body, said primary flow passage not extending through said body on said axis of said body.

3. The gland according to claim 1, wherein a bore diameter of said primary flow passage is larger than a bore diameter of said secondary flow passage.

4. A gland according to claim 1, wherein said plurality of second openings are evenly distributed circumferentially of said body.

5. A gland according to claim 1 wherein said secondary flow passage is disposed obliquely to said primary flow passage.

6. A gland according to claim 5 wherein the acute angle between the centre line of the secondary flow passage and the centre line of the primary flow passage is in the range 20-80 degrees.

7. A gland according to claim 5, wherein the distance of the secondary flow passage to the axis of the body increases progressively in the direction from the first end to the second end.

8. A gland according to any one of claims 1 to 7 further including a bleed passage and first and second bleed ports located at either end of the bleed passage, the first bleed port being located at the side of the body and the second bleed port being located at an end face of the second end of the body.

9. The gland according to claim 8 wherein said drain passage is not in communication with said primary flow passage and is not in communication with said secondary flow passage.

10. A gland according to claim 8 wherein said first vent port is located on the side of said side surface adjacent the end surface of said first end.

11. The gland according to claim 8 further comprising a seat pocket located at said first end and communicating with said primary flow passage, and having a relief groove on a side facing away from said first end.

12. The gland according to claim 8, further comprising a first sealing position configured to provide a first sealing ring and a second sealing position configured to provide a second sealing ring, both said first and second sealing positions being located on said side, said first drain port being located between said first and second sealing positions.

13. The gland of claim 8, further comprising a first seal groove configured to receive a first seal ring and a second seal groove configured to receive a second seal ring, said first and second seal grooves each being located at said side face, said first drain port being located between said first and second seal grooves.

14. The gland according to claim 8, further comprising a draw aperture located at said second end of said body, said draw aperture not communicating with said second vent.

15. A gland according to claim 14 wherein said pull aperture is located on said axis of said body.

16. A fluid end comprising a gland according to any one of claims 1 to 15.

17. The fluid tip of claim 16, further comprising:

the valve box comprises an inner cavity, and the inner cavity comprises a low-pressure cavity, an alternating cavity and a high-pressure cavity;

the gland is located the low pressure chamber, the inner chamber of valve box is the type of falling T structure, the alternating chamber with the low pressure chamber is followed the extending direction setting of the first axis of inner chamber, the alternating chamber with the high pressure chamber is followed the extending direction setting of the second axis of inner chamber, the first axis with the second axis is crossing.

18. The fluid end of claim 17 wherein the valve housing has a fluid feed hole, the fluid feed hole and the high pressure chamber being offset in a direction of extension of the first axis.

19. The fluid tip of claim 17, further comprising a first valve assembly configured to open to communicate the low pressure chamber and the alternating chamber or to close to isolate the low pressure chamber and the alternating chamber, the first valve assembly comprising a spring bracket that is hollowed out and is retained by a ramp with the valve housing.

20. The fluid tip of claim 17, wherein the intersection of the internal cavity includes a first sub-cavity and a second sub-cavity, the first sub-cavity and the second sub-cavity being disposed along a direction of extension of the second axis, the second sub-cavity being closer to a portion of the internal cavity extending along the first axis than the first sub-cavity, a maximum dimension of the second sub-cavity in the direction of extension of the second axis being greater than a maximum dimension of the first sub-cavity in the direction of extension of the second axis,

the size of the second sub-cavity in the extending direction of the first axis is gradually increased from a position far away from the first axis to a position close to the first axis.

21. The fluid end of claim 20 wherein the valve housing is provided with a protective sleeve at a location corresponding to the first sub-chamber and the second sub-chamber.

22. The fluid tip of claim 20, further comprising a second valve assembly configured to open to communicate the alternating chamber and the high pressure chamber or to close to isolate the alternating chamber and the high pressure chamber, the second valve assembly and the second sub-chamber being located on opposite sides of the first sub-chamber.

23. A plunger pump, characterized in that it comprises a fluid end according to any of claims 17-22.

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