CN113819051A

CN113819051A - Fluid end and plunger pump

Info

Publication number: CN113819051A
Application number: CN202111282713.8A
Authority: CN
Inventors: 李晓斌; 王宝杰; 王继鑫; 李朋; 姜琛; 崔海萍; 张树林; 葛安鹏
Original assignee: Yantai Jereh Petroleum Equipment and Technologies Co Ltd
Current assignee: Yantai Jereh Petroleum Equipment and Technologies Co Ltd
Priority date: 2021-11-01
Filing date: 2021-11-01
Publication date: 2021-12-21
Also published as: WO2023070836A1; CN115405514A

Abstract

A fluid end and plunger pump is provided. The fluid end includes: a valve box comprising an inner cavity, the inner cavity comprising an alternating cavity and a low pressure cavity; a first valve assembly configured to open to communicate the low pressure chamber and the alternating chamber or configured to close to isolate the low pressure chamber and the alternating chamber; a first pressure bearing assembly located in the inner cavity; and the second pressure-bearing assembly is positioned in the inner cavity, and the first valve assembly, the first pressure-bearing assembly and the second pressure-bearing assembly are sequentially arranged along the extension direction of the first axis of the inner cavity, so that the maintenance and the service life of the valve box are favorably prolonged.

Description

Fluid end and plunger pump

Technical Field

Embodiments of the present disclosure relate to a hydraulic tip and plunger pump.

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

Embodiments of the present disclosure provide a hydraulic end and plunger pump to facilitate maintenance and extend the life of a valve box.

Embodiments of the present disclosure provide a hydraulic tip, comprising: a valve box comprising an inner cavity, the inner cavity comprising an alternating cavity and a low pressure cavity; a first valve assembly configured to open to communicate the low pressure chamber and the alternating chamber or configured to close to isolate the low pressure chamber and the alternating chamber; a first pressure bearing assembly located in the inner cavity; and the second pressure-bearing assembly is positioned in the inner cavity, and the first valve assembly, the first pressure-bearing assembly and the second pressure-bearing assembly are sequentially arranged along the extension direction of the first axis of the inner cavity.

According to the hydraulic end provided by the embodiment of the disclosure, the first pressure bearing assembly is detachably connected with the valve box, and the second pressure bearing assembly is detachably connected with the valve box.

According to the hydraulic end provided by the embodiment of the disclosure, the first pressure bearing assembly comprises an alternating pressure cover and an alternating pressure cap, the alternating pressure cover is closer to the first valve assembly than the alternating pressure cap, and the alternating pressure cap is in threaded connection with the valve box.

According to a fluid end provided by an embodiment of the present disclosure, a maximum length of the alternating gland on the first axis is less than a maximum length of the alternating gland on the first axis.

According to the hydraulic end provided by the embodiment of the disclosure, a first sealing structure is arranged between the alternating gland and the valve box, and the valve box is provided with a leakage flow channel which is configured to circulate fluid when the first sealing structure is at least partially failed.

According to the hydraulic end provided by the embodiment of the disclosure, the drain channel penetrates through the body of the valve box.

According to the hydraulic end provided by the embodiment of the disclosure, the drainage channel is obliquely arranged relative to the first axis of the inner cavity, and the acute angle formed by the drainage channel and the first axis of the inner cavity is greater than or equal to 30 degrees and less than or equal to 60 degrees.

According to the hydraulic end provided by the embodiment of the disclosure, the first sealing structure comprises a first seal and a second seal, and one end of the drainage channel close to the alternating gland is positioned between the first seal and the second seal.

According to the hydraulic end provided by the embodiment of the disclosure, the first valve assembly comprises a first valve body, a first sealing element and a first valve seat, and the alternating gland is used as a base of the first valve seat.

According to a fluid end provided by an embodiment of the present disclosure, the alternating gland has a low pressure fluid passage that communicates with an upper fluid port of the valve housing.

According to the hydraulic end provided by the embodiment of the disclosure, the second pressure-bearing assembly comprises a suction gland and a suction pressure cap, the suction gland is closer to the first pressure-bearing assembly than the suction pressure cap, and the suction pressure cap is in threaded connection with the valve box.

According to a fluid end provided by an embodiment of the present disclosure, the alternating gland and the suction gland are disposed on opposite sides of the alternating gland cap.

According to an embodiment of the present disclosure, there is provided a fluid end, further including a second valve assembly and a third pressure-bearing assembly, wherein the inner cavity further includes a high-pressure cavity, the second valve assembly is configured to be opened to communicate the alternating cavity and the high-pressure cavity or configured to be closed to separate the alternating cavity and the high-pressure cavity, the third pressure-bearing assembly is located in the inner cavity and is sequentially arranged with the second valve assembly in an extending direction of a second axis of the inner cavity, an area of the inner cavity between the second valve assembly and the third pressure-bearing assembly is the high-pressure cavity, and the first axis intersects the second axis.

According to the hydraulic end that this disclosed embodiment provided, the inner chamber is the type of falling T structure, alternate chamber with the high pressure chamber is followed the extending direction setting of the second axis of inner chamber.

According to the hydraulic end provided by the embodiment of the disclosure, the valve box is provided with the liquid feeding hole, and the liquid feeding hole and the high-pressure cavity are arranged in a staggered mode in the extending direction of the first axis.

According to the hydraulic end provided by the embodiment of the disclosure, the first pressure bearing assembly and the second pressure bearing assembly are respectively arranged on two sides of the upper liquid hole in the extending direction of the first axis.

According to the fluid end provided by the embodiment of the present disclosure, the intersection of the inner cavity includes a first sub-cavity and a second sub-cavity, the first sub-cavity and the second sub-cavity are arranged along the extending direction of the second axis, the second sub-cavity is closer to the part of the inner cavity extending along the first axis than the first sub-cavity, the maximum dimension of the second sub-cavity in the extending direction of the second axis is larger than the maximum dimension of the first sub-cavity in the extending direction of the first axis, and the dimension of the second sub-cavity in the extending direction of the first axis gradually increases from a position far away from the first axis to a position close to the first axis.

According to the hydraulic end provided by the embodiment of the disclosure, the valve box is provided with a protective sleeve at the position corresponding to the first sub-cavity and the second sub-cavity.

According to the hydraulic end that this disclosed embodiment provided, first valve module includes spring bracket, spring bracket is hollow out construction, and with the valve box carries on spacingly through the inclined plane.

Embodiments of the present disclosure also provide a plunger pump including any of the above-described fluid ends.

Drawings

To more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below, and it is apparent that the drawings in the following description relate only to some embodiments of the present disclosure and are not limiting to the present disclosure.

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

Fig. 2 is a schematic view of a fluid end in the plunger pump shown in fig. 1.

Fig. 3 is a schematic view of a valve box in the fluid end shown in fig. 2.

Fig. 4 is a cross-sectional view of a fluid end provided by an embodiment of the present disclosure.

Fig. 5 is a schematic diagram of the regions of the internal cavity in a hydraulic-end valve box provided by an embodiment of the present disclosure.

Fig. 6 is a schematic diagram of a valve housing of a fluid end provided by an embodiment of the present disclosure.

Fig. 7 is a perspective view of a fluid end provided by an embodiment of the present disclosure.

Fig. 8 is a schematic view of another fluid end valve box provided by embodiments of the present disclosure.

FIG. 9 is a schematic illustration of a intersection of the internal chambers of a valve box in a hydraulic end provided by an embodiment of the present disclosure.

FIG. 10 is a schematic view of the intersection of the internal chambers of the valve box in another fluid end provided by an embodiment of the present disclosure.

Fig. 11 is a cross-sectional view of a fluid end provided by an embodiment of the present disclosure.

Fig. 12 is a schematic view of the fluid end valve box of fig. 11.

Fig. 13A is a partial schematic view at the bleed passage in the valve housing of fig. 11.

FIG. 13B is a partial schematic view of the packing set and the packing set extrusion in the valve box of FIG. 11.

FIG. 14 is a schematic illustration of a second valve assembly in a hydraulic end provided by an embodiment of the present disclosure.

Fig. 15 is a schematic diagram of a valve housing on the discharge side of a hydraulic end provided by an embodiment of the present disclosure.

Fig. 16 is a schematic view of a sealing structure on a discharge side of a fluid end according to an embodiment of the present disclosure.

Fig. 17 is a schematic diagram of a valve housing on the suction side of a hydraulic end provided by an embodiment of the present disclosure.

Fig. 18 is a schematic view of a sealing structure on the suction side of a hydraulic end provided by an embodiment of the present disclosure.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more apparent, the technical solutions of the embodiments of the present disclosure will be described clearly and completely with reference to the drawings of the embodiments of the present disclosure. It is to be understood that the described embodiments are only a few embodiments of the present disclosure, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the disclosure without any inventive step, are within the scope of protection of the disclosure.

Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this disclosure belongs. The use of "first," "second," and similar terms in this disclosure is not intended to indicate any order, quantity, or importance, but rather is 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. 1 is a sectional view of a plunger pump. Fig. 2 is a schematic view of a fluid end in the plunger pump shown in fig. 1. Fig. 3 is a schematic view of a valve box in the fluid end shown in fig. 2. As shown in fig. 1, the plunger pump 003 includes a power end 002 and a fluid end 001. As shown in fig. 1 and 2, 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. 1 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. 2, the fluid end 001 further includes a valve seat 021, a spring 022, a suction gland 023, a suction gland 024, a spring 025, a drain hole 026, a packing assembly 027 for sealing, and a packing gland 028. Fig. 3 shows a cruciform arrangement of the valve housing 01.

As shown in fig. 1 and 2, 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. 1 to 3, a valve box of a general hydraulic end is a cross intersecting structure, as shown in fig. 3, 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 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 is cracked 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.

Embodiments of the present disclosure provide a hydraulic end having a T-shaped valve housing and a plunger pump including the same to extend the service life of the valve housing. Embodiments of the present disclosure also provide a fluid end having two sets of pressure bearing assemblies on the suction side and a plunger pump including the fluid end to facilitate maintenance and extend the service life of the valve housing.

The hydraulic tip and plunger pump provided by embodiments of the present disclosure are described below.

Fig. 4 is a schematic diagram of a hydraulic terminal provided in an embodiment of the disclosure. Fig. 5 is a schematic diagram of the regions of the internal cavity in a hydraulic-end valve box provided by an embodiment of the present disclosure. Fig. 6 is a schematic diagram of a valve housing of a fluid end provided by an embodiment of the present disclosure. Fig. 7 is a perspective view of a fluid end provided by an embodiment of the present disclosure. Fig. 8 is a schematic view of another fluid end valve box provided by embodiments of the present disclosure. FIG. 9 is a schematic illustration of a intersection of the internal chambers of a valve box in a hydraulic end provided by an embodiment of the present disclosure. Fig. 9(a) is a cross-sectional view of the XY plane of the inner chamber of the valve housing. Fig. 9(b) is a schematic diagram of the YZ plane of the inner cavity of the valve box. FIG. 10 is a schematic view of the intersection of the internal chambers of the valve box in another fluid end provided by an embodiment of the present disclosure. 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. 7 shows the X direction, the Y direction, and the Z direction. For example, the X direction is an extending direction of a first axis a1 mentioned later, and the Y direction is an extending direction of a second axis a2 mentioned later. Fig. 11 is a cross-sectional view of a fluid end provided by an embodiment of the present disclosure. Fig. 12 is a schematic view of the fluid end valve box of fig. 11.

Fig. 13A is a partial schematic view at the bleed passage in the valve housing of fig. 11. FIG. 13B is a partial schematic view of the packing set and the packing set extrusion in the valve box of FIG. 11.

As shown in fig. 11, embodiments of the present disclosure provide a fluid end comprising: a valve box 70, a first valve assembly V1, a first pressure containing assembly M1, and a second pressure containing assembly M2.

As shown in fig. 11, 5, and 6, the valve housing 70 includes an inner chamber 07, and the inner chamber 07 includes an alternating chamber 07b and a low pressure chamber 07 a.

As shown in fig. 11 and 5, the first valve assembly V1 is configured to open to communicate the low pressure chamber 07a and the alternating chamber 07b or to close to separate the low pressure chamber 07a and the alternating chamber 07 b. The area of the inner chamber 07 between the first valve assembly V1 and the second pressure containing assembly M2 is the low pressure chamber 07 a.

As shown in fig. 11, the first pressure bearing assembly M1 is in contact with the first valve assembly V1.

As shown in fig. 11, the second bearing assembly M2 is disposed in series with the first bearing assembly M1 along the extension direction of the first axis a1 of the inner cavity 07.

As shown in fig. 11, the first valve assembly V1, the first pressure-containing assembly M1 and the second pressure-containing assembly M2 are arranged in this order along the extension direction of the first axis a1 of the inner cavity 07.

Fig. 11 and 4 show the suction side 70a, the discharge side 70b and the plunger side 70c of the fluid end.

According to the hydraulic end provided by the embodiment of the disclosure, two sets of pressure bearing assemblies are arranged on the suction side 70a, namely, a first pressure bearing assembly M1 and a second pressure bearing assembly M2 are arranged, the first valve assembly V1 is connected with the valve box 70 through the first pressure bearing assembly M1 instead of being directly seated on the valve box 70, the first valve assembly V1 is not in direct contact with the valve box, the maintenance is convenient, and the service life of the valve box is prolonged.

For example, as shown in FIG. 11, a first pressure bearing assembly M1 is removably connected to the valve housing 70 and a second pressure bearing assembly M2 is removably connected to the valve housing 70 to facilitate removal of the plunger 81 from the suction side 70 a.

For example, as shown in fig. 11, the first pressure bearing assembly M1 includes a gland 13 and a gland 23, the gland 13 being closer to the first valve assembly V1 than the gland 23, the gland 23 being threadably connected to the valve housing 70.

For example, alternating gland 13 is subject to alternating loads and alternating gland 23 is subject to alternating loads. The gland 13 may also be referred to as an intermediate gland or directly as a gland and the gland 23 may also be referred to as an intermediate gland or directly as a gland.

For example, as shown in fig. 11, the maximum length of gland 13 in first axis a1 is less than the maximum length of gland 23 in first axis a 1.

In the hydraulic end provided by the embodiment of the present disclosure, the first valve component V1 is not directly "seated" on the valve box 70, but is indirectly connected with the valve box 70 through the alternating pressure cover 13, the alternating pressure cover 13 is forced to move, and therefore, the alternating pressure cap 23 is required to be used for fixing and limiting, for example, the alternating pressure cap 23 is in contact with the alternating pressure cover 13, and the alternating pressure cap 23 is fastened with the valve box 70 by screw threads, but not limited thereto. When alternating gland 13 is subjected to alternating load, load can be transmitted to the screw thread of alternating pressure cap 23, and because the contact area between alternating gland 13 and alternating pressure cap 23 is small, and the screw thread of alternating pressure cap 23 is long, through finite element analysis, the stress at the screw thread of alternating pressure cap 23 is smaller than the stress at the screw thread of the pressure cap at a common hydraulic end, and the hydraulic end provided by the embodiment of the disclosure can prolong the service life of valve box 70.

For example, as shown in fig. 11 and 13A, a first seal structure SE is provided between the gland 13 and the valve housing 70, and the valve housing 70 has a vent passage 7000, the vent passage 7000 being configured to communicate fluid when the first seal structure SE at least partially fails. Of course, in other embodiments, the bleed flow path 7000 may not be provided in the valve housing of the hydraulic side.

For example, as shown in fig. 11, 12 and 13A, a bleed flow path 7000 extends through the body 100 of the valve box 70. Bleed flow path 7000 leads from the outside of valve housing body 77 into interior cavity 07.

For example, as shown in fig. 11, 12 and 13A, to facilitate manufacturing and to provide a valve box with greater strength, vent path 7000 is angled relative to first axis a1 of interior cavity 07 such that an acute angle θ a of vent path 7000 with respect to first axis a1 of interior cavity 07 is greater than or equal to 30 degrees and less than or equal to 60 degrees.

For example, as shown in fig. 11, 12, and 13A, the end of the bleed flow passage 7000 remote from the internal cavity 07 is closer to the suction side 70a than the end of the bleed flow passage 7000 close to the internal cavity 07. That is, as shown in fig. 11, the end of bleed flow passage 7000 remote from internal cavity 07 is further to the right than the end of bleed flow passage 7000 near internal cavity 07.

For example, as shown in fig. 11 and 13A, the first seal structure SE includes a first seal SE1 and a second seal SE2, with the end of the bleed flow passage 7000 adjacent to the gland 13 being located between the first seal SE1 and the second seal SE 2. For example, the first seal SE1 includes a seal ring, and the second seal SE2 includes a seal ring.

As shown in fig. 11 and 13A, the seal groove of the first seal structure SE is provided in the alternating pressure cover 13. In other embodiments, the seal groove of the first seal structure SE may also be provided in the valve housing 70.

For example, as shown in fig. 4 and 11, the first valve assembly V1 includes a valve body 1a, a seal 1b, and a valve seat 1c, and the alternating pressure cover 13 serves as a base of the valve seat 1 c.

For example, as shown in fig. 4 and 11, the first valve assembly V1 further includes a spring 1d and a spring support 1 e.

For example, as shown in fig. 4 and 11, the spring support 1e includes a hollowed-out structure e0, and is limited by the inclined surface S01 with the valve box 70. 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. 4 and 11, when the seal 1b is fitted into the valve body 1a and the first valve assembly V1 is opened, the valve body 1a fitted with the seal 1b moves leftward, and the low pressure chamber 07a and the alternating chamber 07b communicate with each other.

For example, as shown in fig. 4, 5, 6, 8, and 11, the valve housing 70 has a weep hole 700. Fig. 4, 5, 6 and 11 show the liquid wells on a single side. Fig. 8 shows a double-sided weep hole 700: upper fluid port 700a and upper fluid port 700 b. The valving 70 may be single sided or double sided. For example, the liquid on one side can meet the operation of small discharge capacity and low sand ratio, and the sand blocking phenomenon is avoided; the liquid feeding on the two sides can meet the operation of large discharge capacity and high sand ratio, the liquid feeding stability can be ensured by the liquid feeding holes on the two sides, and the sand blocking risk is reduced.

For example, as shown in fig. 11 and 13A, the alternating gland 13 has a low-pressure fluid passage 130, and the low-pressure fluid passage 130 communicates with an upper fluid port 700 of the valve housing 70. The low pressure fluid passage 130 may also be referred to as a first passage 130.

For example, as shown in fig. 11 and 13A, the alternating pressure cap 23 has a low pressure fluid passage 230, and the low pressure fluid passage 230 communicates with the upper fluid hole 700 of the valve housing 70. The low pressure fluid passage 230 may also be referred to as a second passage 230.

For example, as shown in fig. 11, the second pressure bearing assembly M2 includes a suction gland 33 and a suction pressure cap 43, the suction gland 33 is closer to the first pressure bearing assembly M1 than the suction pressure cap 43, and the suction pressure cap 43 is screw-coupled with the valve housing 70.

For example, as shown in fig. 11, a first pressure bearing assembly M1 and a second pressure bearing assembly M2 are disposed on opposite sides of the upper fluid opening 700. For example, as shown in fig. 11, a first pressure bearing assembly M1 and a second pressure bearing assembly M2 are provided on both sides of the upper fluid port 700 in the extending direction of the first axis a 1. As shown in fig. 11, the first pressure bearing assembly M1 is on the left side of the upper fluid port 700, and the second pressure bearing assembly M2 is on the right side of the upper fluid port 700.

For example, as shown in fig. 11, alternating gland 13 and suction gland 33 are disposed on opposite sides of alternating gland 23. For example, as shown in fig. 11, the alternating pressure cap 23 and the suction gland 33 are disposed on opposite sides of the upper fluid hole 700. As shown in fig. 11, the alternate-pressure cap 23 is provided on the left side of the upper fluid hole 700, and the suction cap 33 is provided separately on the right side of the upper fluid hole 700.

The first valve assembly V1 of the fluid end shown in fig. 4 includes a base 1 f. And the use of the crossover gland 13 in the fluid end shown in fig. 11 as the first valve assembly V1 includes a seat to make the fluid end more compact. The base 1f shown in fig. 4 has a low-pressure liquid passage 330, and the low-pressure liquid passage 330 communicates with the upper liquid hole 700 of the valve housing 70.

For example, as shown in fig. 4, 5, 6 and 11, the inner cavity 07 has an inverted T-shaped configuration, and the alternating cavity 07b and the high pressure cavity 07c are disposed along the extension direction of the second axis a2 of the inner cavity 07, and the first axis a1 intersects the second axis a 2. Thus, the fluid end includes an interior cavity 07 having an inverted T-shaped configuration, and the valve housing 70 may be referred to as a T-shaped valve housing. The embodiment of the disclosure is illustrated with the first axis a1 perpendicular to the second axis a 2.

For example, as shown in fig. 4 and 11, the fluid end further includes a second valve assembly V2, the internal cavity 07 further includes a high pressure chamber 07c, and the second valve assembly V2 is 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 and the high pressure chamber 07 c.

For example, as shown in fig. 4 and 11, 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 base 2 f.

For example, as shown in fig. 4 and 11, 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 are communicated.

As shown in fig. 4 and 11, the second valve assembly V2 is adjacent the outlet orifice 7005 and is opened 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. 4 and 11, the hydraulic end further includes a third pressure-bearing assembly M3, the third pressure-bearing assembly M3 is located in the inner cavity, and the third pressure-bearing assembly M3 and the second valve assembly V2 are arranged in sequence in the extending direction of the second axis a 2. The area of the internal chamber 07 between the second valve assembly V2 and the third pressure containing assembly M3 is the high pressure chamber 07 c.

As shown in fig. 4 and 11, the third bearing assembly M3 includes a gland 40 and a gland 50. The gland 40 may be referred to as a discharge gland 40 and the gland 50 may be referred to as a discharge gland 50.

For example, as shown in fig. 4 and 11, 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, 6 and 11, the intersection of the 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 the second axis a2, the second sub-cavity 072 is closer to the portion (horizontal cavity) of the inner cavity 07 extending along the first axis a1 than the first sub-cavity 071, and in order to alleviate the stress concentration, the maximum dimension h2 of the second sub-cavity 072 in the extension direction of the second axis a2 is greater than the maximum dimension h1 of the first sub-cavity 071 in the extension direction of the 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. 4 and, 6 and 11, 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 from the first axis a1 to a location proximal to the first axis a 1. That is, the dimension D1 of the second subchamber 072 in the direction of extension of the first axis a1 gradually increases from top to bottom.

For example, as shown in fig. 4, 6, and 11, the portion of valve box 70 used to form second subchamber 072 is angled 30-80 degrees from first axis a 1. 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. 4 and 11, the first sub-cavity 071 is a cylindrical cavity, but is not limited thereto. For example, as shown in fig. 11, the second sub-cavity 072 is a truncated cone shaped cavity, but is not limited thereto.

For example, as shown in fig. 4 and 11, 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. 4 and 11, the valve housing 70 is formed in a flare shape at the 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. 4 and 11, a boot 73 is provided at the "flare" of the interior chamber of the valve housing 70 in order to prevent wear to the interior chamber. After the inner cavity is abraded, the surface roughness of the inner cavity is increased, and in addition, fatigue cracks are easily generated on the surface of the inner cavity through high-pressure operation, so that the joint (matched) protection mode of the bell mouth and the protective sleeve 73 at the intersecting position can reduce the cracking risk and prolong the service life of the valve box. For example, the protective sleeve 73 may be mounted to the inside of the valve housing by cold-fitting, but is not limited to cold-fitting, and the protective sleeve 73 may be mounted by machining or hot-working.

Fig. 9 and 10 show the bell 76, the horizontal chamber 0701, and the body 77 of the valve housing 70.

The valve box inner cavity of the hydraulic end provided by the embodiment of the disclosure is of a T-shaped structure, and the intersecting position is designed into a horn mouth form, so that the problem of stress concentration at the intersecting line of the inner cavity is solved.

For example, as shown in fig. 6 and 11, the alternating pressure cover 13 is located in the low pressure chamber 07a, the alternating pressure cap 23 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 arranged along the extending direction of the first axis a1 of the inner chamber 07, the alternating chamber 07b and the high pressure chamber 07c are arranged along the extending direction of the second axis a2 of the inner chamber 07, and the first axis a1 intersects the second axis a 2. Fig. 6 shows a first axis a1 and a second axis a2 of the lumen 07. As shown in fig. 6 and 12, the inner chamber 07 includes a horizontal chamber 0701 and a vertical chamber 0702.

For example, as shown in fig. 6 and 11, 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 structure of the valve box of the hydraulic end provided by the embodiment of the disclosure has the following characteristics compared with the valve box of the common hydraulic end.

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

The lumen of the cross-shaped intersecting structure is shown in fig. 3, 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 valve box in the hydraulic end provided by the embodiment of the disclosure has the advantages that the right angle does not exist at the intersecting part of the inner cavity, the transition of the intersecting part of the inner cavity is smooth, the optimal design is carried out at the position where stress concentration is most easily generated, the intersecting part is in a bell mouth shape, no stress concentration point exists, and the stress concentration effect is obviously improved by analyzing the stress concentration effect in mechanics.

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 valve box in the hydraulic end provided by the embodiment of the disclosure is of an integral structure, is tight in sealing and high-pressure resistant, uses fewer sealing elements and does not use bolts, and is simple and compact in structure and low in risk of leakage of the valve box.

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 hydraulic end provided by the embodiment of the disclosure does not have the problem of inconvenient maintenance, the axis of the plunger coincides with the first axis (horizontal axis) of the valve box, the suction side is provided with the first pressure-bearing assembly M1 and the second pressure-bearing assembly M1, the axis of the first pressure-bearing assembly M1 and the axis of the second pressure-bearing assembly M1 both coincide with the axis of the plunger, and the hydraulic end can be maintained by normal operation of a well site.

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 11, the alternating pressure cover 13 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 alternating pressure cap 23, and the alternating pressure cap 23 is in threaded engagement with the valve box 70.

For example, as shown in fig. 4, 11 and 13B, 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. 5-6, 12, and 13B, the inner cavity 09 further includes a plunger cavity 07d, the plunger cavity 07d configured to house the plunger 81. As shown in fig. 12, the plunger cavity 07d, the alternating cavity 07b, and the low pressure cavity 07d are arranged in this order along the extending direction of the first axis a1 of the inner cavity 07.

For example, as shown in fig. 4, 11 and 13B, the fluid end further includes a packing assembly 82, the packing assembly 82 including a packing 821, a spacer ring 822, and a compression ring 823.

For example, as shown in fig. 4, 11 and 13B, the packing set 821 includes three packing rings, but of course, the number of packing rings is not limited to that shown in the drawings 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. 4, 11 and 13B, the plunger side 70c of the valve housing 70 is provided with a lubricating oil passage 7007 for lubricating a packing set 821 (rubber) to make the reciprocating movement 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. 4, 11 and 13B, 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. 4, 11, and 13B, the hydraulic end also includes a packing cap 83, the packing cap 83 configured to press against the packing assembly 82.

For example, as shown in fig. 4, 11, and 13B, the packing set 821 is fixed by a 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. 4, 11, and 13B, 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 against the packing sleeve 84.

For example, as shown in fig. 4, 11 and 13B, the packing sleeve 84 is axially retained by a shoulder and packing sleeve 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. 4, 11, and 13B, 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. 4, 6, 7 and 11 also show the discharge side 70b of the fluid end. As shown in fig. 11 and 7, 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 outlet orifice 7005 may be connected to the outlet flange and internally communicate a high pressure fluid.

For example, as shown in fig. 4, 6, and 11, the valve housing 70 is provided with a suction-side screw 7001, a discharge-side screw 7002, and a plunger-side screw 7003. The suction cap 43 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. 11, the first valve assembly V1 and the second valve assembly V2 may be interchangeable. 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. 11, with the first valve assembly V1, the valve seat 1c is disposed in the valve seat groove of the alternating pressure cover 13, and the left side of the alternating pressure cover 13 serves as a base of the valve seat 1c for fixing the valve seat 1 c. For example, the alternating gland 13 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 crossover gland 13. 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. 11, 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 (moves 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 low-pressure fluid channel 230 and the low-pressure fluid channel 130 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. 14 is a schematic illustration of a second valve assembly in a hydraulic end provided by an embodiment of the present disclosure. As shown in fig. 14, 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. 14, 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. 15 is a schematic diagram of a valve housing on the discharge side of a hydraulic end provided by an embodiment of the present disclosure. Fig. 16 is a schematic view of a sealing structure on a discharge side of a fluid end according to an embodiment of the present disclosure. Fig. 17 is a schematic diagram of a valve housing on the suction side of a hydraulic end provided by an embodiment of the present disclosure. Fig. 18 is a schematic view of a sealing structure on the suction side of a hydraulic end provided by an embodiment of the present disclosure.

Fig. 14 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. 10 and 11, a seal 1021 is provided to effect a seal between the second valve assembly V2 and the valve box 70.

Fig. 15 shows a seal groove 901 and fig. 16 shows a seal 902. A seal 902 is provided to effect a seal against the high pressure chamber of the inner chamber.

Fig. 17 shows a seal groove 903, and fig. 18 shows a seal 904. A seal 904 is provided to effect a seal against the low pressure chamber of the internal chamber.

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

The embodiment of the present disclosure provides the fluid end having at least one of the following effects.

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

The valve box at the hydraulic end provided by the embodiment of the disclosure has the advantages that the right angle does not exist at the intersecting part of the inner cavity, the intersecting part of the inner cavity is in smooth transition, the shape design is carried out at the position where stress concentration is most easily generated, the intersecting part is in a bell mouth shape, no stress concentration point exists, and the stress concentration effect is obviously improved by analyzing the stress concentration effect in mechanics.

2) Simple structure, the leakproofness is strong.

The valve box of the hydraulic end provided by the embodiment of the disclosure is of an integral structure, is tight in sealing and high-pressure resistant, uses fewer sealing elements and does not use bolts, and is simple and compact in structure, and the risk of leakage of the valve box is lower.

3) The maintenance is convenient.

According to the hydraulic end provided by the embodiment of the disclosure, the axis of the plunger coincides with the first axis (horizontal axis) of the valve box, the suction side is provided with the pressing cap (the axis of the pressing cap coincides with the axis of the plunger, and the pressing cap is detachable), and the maintenance can be performed according to the conventional operation of a well site.

In the fluid end provided by the embodiments of the present disclosure, fig. 4 and 11 show that the fluid end includes a T-shaped valve box, and fig. 11 shows that the fluid end includes two sets of pressure bearing assemblies. It should be noted that, in the hydraulic end provided with two sets of pressure-bearing assemblies, a T-shaped valve box may not be adopted; in the hydraulic end adopting the T-shaped valve box, two sets of pressure-bearing assemblies can be omitted and can be arranged as required.

For example, the hydraulic end and the plunger pump can be applied to fracturing/cementing equipment of oil and gas fields.

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

Claims

1. A fluid end comprising:

a valve box comprising an inner cavity, the inner cavity comprising an alternating cavity and a low pressure cavity;

a first valve assembly configured to open to communicate the low pressure chamber and the alternating chamber or configured to close to isolate the low pressure chamber and the alternating chamber;

a first pressure bearing assembly located in the inner cavity; and

a second pressure bearing assembly located in the internal cavity,

the first valve assembly, the first pressure-bearing assembly and the second pressure-bearing assembly are sequentially arranged along the extension direction of the first axis of the inner cavity.

2. The fluid end of claim 1 wherein the first pressure bearing assembly is removably coupled to the valve housing and the second pressure bearing assembly is removably coupled to the valve housing.

3. The fluid end of claim 1 wherein the first pressure bearing assembly includes a gland and a cap, the gland being closer to the first valve assembly than the cap, the cap being threadably connected to the valve housing.

4. The fluid end of claim 3 wherein a maximum length of the alternating gland in the first axis is less than a maximum length of the alternating gland in the first axis.

5. The fluid end of claim 3 wherein a first seal structure is disposed between the alternating gland and the valve housing, the valve housing having a vent passage configured to communicate fluid upon at least partial failure of the first seal structure.

6. The fluid end of claim 5 wherein the bleed passage extends through a body of the valve housing.

7. The fluid tip of claim 5, wherein the bleed passage is disposed obliquely to the first axis of the lumen, the bleed passage forming an acute angle with the first axis of the lumen that is greater than or equal to 30 degrees and less than or equal to 60 degrees.

8. The fluid end of claim 5 wherein the first seal arrangement includes a first seal and a second seal, an end of the drain passage proximate the crossover gland being located between the first seal and the second seal.

9. The fluid tip of claim 8, wherein the first valve assembly includes a first valve body, a first seal, and a first valve seat, the alternating gland serving as a seat for the first valve seat.

10. The fluid end of claim 3 wherein the alternating gland has a low pressure fluid passage in communication with an upper fluid port of the valve housing.

11. The fluid end of claim 3 wherein the second pressure bearing assembly includes a suction gland and a suction cap, the suction gland being closer to the first pressure bearing assembly than the suction cap, the suction cap being threadably connected to the valve housing.

12. The fluid end of claim 11 wherein the alternating gland and the suction gland are disposed on opposite sides of the alternating gland cap.

13. The fluid end of any one of claims 1-12 further comprising a second valve assembly and a third pressure bearing assembly, wherein the inner chamber further comprises a high pressure chamber, the second valve assembly is configured to open to communicate with the alternating chamber and the high pressure chamber or is configured to close to separate the alternating chamber and the high pressure chamber, the third pressure bearing assembly is located in the inner chamber and is disposed in series with the second valve assembly in a direction extending along a second axis of the inner chamber, an area of the inner chamber between the second valve assembly and the third pressure bearing assembly is the high pressure chamber, and the first axis intersects the second axis.

14. The fluid tip of claim 13, wherein the inner chamber is an inverted T-shaped structure, and the alternating chamber and the high pressure chamber are disposed along a direction of extension of the second axis of the inner chamber.

15. The fluid end of claim 14 wherein the valve housing has a weep hole, the weep hole and the high pressure chamber being offset in a direction of extension of the first axis.

16. The fluid end of claim 15 wherein the first and second bearing assemblies are disposed on opposite sides of the upper fluid bore in a direction of extension of the first axis.

17. The fluid tip of claim 14, wherein the intersection of the inner 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 inner 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 first 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.

18. The fluid end of claim 17 wherein the valve housing is provided with a protective sleeve at a location corresponding to the first and second sub-chambers.

19. The fluid end of any one of claims 1-12 wherein the first valve assembly includes a spring support that is hollow and is retained with the valve housing by a ramp.

20. A plunger pump comprising a fluid end according to any one of claims 1-19.