Liquid end and plunger pump

Abstract

Provided are a hydraulic end and a plunger pump. The hydraulic end includes a valve box having an inner cavity, the inner cavity including an alternating cavity and a low-pressure cavity; a first valve assembly configured to open to connect the low-pressure cavity and the alternating cavity or to close to separate the low-pressure cavity and the alternating cavity, the first valve assembly including a valve body, a seal, a valve seat, and a base; and a second pressure-bearing assembly located in the inner cavity. The valve seat, the base, and the second pressure-bearing assembly are sequentially arranged along an extension direction of a first axis of the inner cavity to facilitate maintenance and extend the service life of the valve box.

Description

[0001] This application is a divisional application of patent application No. 202111282713.8, with the application date of November 1, 2021 and the invention name being "Hydraulic End and Plunger Pump". Technical Field

[0002] Embodiments of the present disclosure relate to a fluid end and a plunger pump. Background Art

[0003] Currently, hydraulic fracturing is the primary method for increasing oil and gas production, and plunger pumps are the primary equipment for pumping the fracturing medium during these operations. In other words, throughout the entire oil and gas production process, any process requiring the delivery of a medium into the well at a specific pressure requires a plunger pump. Summary of the Invention

[0004] Embodiments of the present disclosure provide a hydraulic end and a plunger pump to facilitate maintenance and extend the service life of a valve box.

[0005] An embodiment of the present disclosure provides a hydraulic 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 be opened to connect the low-pressure cavity and the alternating cavity or to be closed to separate the low-pressure cavity and the alternating cavity; a first pressure-bearing assembly, located in the inner cavity; and a second pressure-bearing assembly, located in the inner cavity, the first valve assembly, the first pressure-bearing assembly and the second pressure-bearing assembly being arranged in sequence along the extension direction of the first axis of the inner cavity.

[0006] According to the hydraulic end provided by an embodiment of the present disclosure, the first pressure-bearing component is detachably connected to the valve box, and the second pressure-bearing component is detachably connected to the valve box.

[0007] According to the hydraulic end provided in an embodiment of the present disclosure, the first pressure-bearing assembly includes 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 threadedly connected to the valve box.

[0008] According to the hydraulic end provided by an embodiment of the present disclosure, the maximum length of the alternating pressure cover on the first axis is smaller than the maximum length of the alternating pressure cap on the first axis.

[0009] According to the hydraulic end provided by an embodiment of the present disclosure, a first sealing structure is provided between the alternating pressure cover and the valve box. The valve box has a leakage channel configured to circulate fluid when the first sealing structure at least partially fails.

[0010] According to the hydraulic end provided by an embodiment of the present disclosure, the leakage channel runs through the body of the valve box.

[0011] According to the hydraulic end provided in an embodiment of the present disclosure, the leakage channel is inclined relative to the first axis of the inner cavity, and the acute angle formed by the leakage 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.

[0012] According to the hydraulic end provided by an embodiment of the present disclosure, the first sealing structure includes a first seal and a second seal, and an end of the leakage channel close to the alternating pressure cover is located between the first seal and the second seal.

[0013] According to the hydraulic end provided by an embodiment of the present disclosure, the first valve assembly includes a first valve body, a first sealing member and a first valve seat, and the alternating pressure cover serves as a base of the first valve seat.

[0014] According to the hydraulic end provided by the embodiment of the present disclosure, the alternating pressure cover has a low-pressure fluid channel, and the low-pressure fluid channel is communicated with the upper liquid hole of the valve box.

[0015] According to the hydraulic end provided in an embodiment of the present disclosure, the second pressure-bearing component includes a suction pressure cover and a suction pressure cap, the suction pressure cover is closer to the first pressure-bearing component than the suction pressure cap, and the suction pressure cap is connected to the valve box by threads.

[0016] According to the hydraulic end provided by the embodiment of the present disclosure, the alternating pressure cover and the suction pressure cover are respectively arranged on two opposite sides of the alternating pressure cap.

[0017] According to the hydraulic end provided in an embodiment of the present disclosure, the hydraulic end also includes a second valve assembly and a third pressure-bearing assembly, wherein the inner cavity also includes a high-pressure chamber, the second valve assembly is configured to open to connect the alternating chamber and the high-pressure chamber or to be configured to close to separate the alternating chamber and the high-pressure chamber, the third pressure-bearing assembly is located in the inner cavity, and is arranged in sequence with the second valve assembly in the extension direction of the second axis of the inner cavity, the area of ​​the inner cavity located between the second valve assembly and the third pressure-bearing assembly is the high-pressure chamber, and the first axis intersects with the second axis.

[0018] According to the hydraulic end provided by the embodiment of the present disclosure, the inner cavity has an inverted T-shaped structure, and the alternating cavity and the high-pressure cavity are arranged along the extension direction of the second axis of the inner cavity.

[0019] According to the hydraulic end provided by an embodiment of the present disclosure, the valve box has an upper liquid hole, and the upper liquid hole and the high-pressure chamber are staggered in the extension direction of the first axis.

[0020] According to the hydraulic end provided by an embodiment of the present disclosure, the first pressure-bearing component and the second pressure-bearing component are respectively arranged on both sides of the upper liquid hole in the extension direction of the first axis.

[0021] According to the hydraulic end provided in an 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 extension 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 extension direction of the second axis is greater than the maximum dimension of the first sub-cavity in the extension direction of the first axis, and the dimension of the second sub-cavity in the extension direction of the first axis gradually increases from a position away from the first axis to a position close to the first axis.

[0022] According to the hydraulic end provided by an embodiment of the present disclosure, the valve box is provided with protective sleeves at positions corresponding to the first sub-cavity and the second sub-cavity.

[0023] According to the hydraulic end provided in an embodiment of the present disclosure, the first valve assembly includes a spring bracket, the spring bracket is a hollow structure, and is limited by an inclined surface with the valve box.

[0024] An embodiment of the present disclosure further provides a plunger pump comprising any of the above-mentioned hydraulic ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the drawings of the embodiments will be briefly introduced below. Obviously, the drawings in the following description only relate to some embodiments of the present disclosure, rather than limiting the present disclosure.

[0026] Figure 1 A cross-sectional view of a plunger pump.

[0027] Figure 2 for Figure 1 Schematic diagram of the hydraulic end of the plunger pump shown.

[0028] Figure 3 for Figure 2 Schematic diagram of the valve box in the fluid end shown.

[0029] Figure 4 A cross-sectional view of a fluid end provided in accordance with an embodiment of the present disclosure.

[0030] Figure 5 A schematic diagram of various areas of an inner cavity in a valve box of a hydraulic end provided in an embodiment of the present disclosure.

[0031] Figure 6 A schematic diagram of a valve box of a fluid end provided in accordance with an embodiment of the present disclosure.

[0032] Figure 7 A perspective view of a fluid end provided for an embodiment of the present disclosure.

[0033] Figure 8 A schematic diagram of another valve box of a hydraulic end provided in an embodiment of the present disclosure.

[0034] Figure 9 A schematic diagram of the intersection of the inner cavities of a valve box in a hydraulic end provided in an embodiment of the present disclosure.

[0035] Figure 10 A schematic diagram of the intersection of the inner cavities of another valve box in a fluid end provided in an embodiment of the present disclosure.

[0036] Figure 11 A cross-sectional view of a fluid end provided in accordance with an embodiment of the present disclosure.

[0037] Figure 12 for Figure 11 Schematic diagram of the valve box of the hydraulic end is shown.

[0038] Figure 13A for Figure 11 A partial schematic diagram of the leakage channel in the valve box.

[0039] Figure 13B for Figure 11 A partial schematic diagram of the packing sleeve in the valve box and the pressure relief area of ​​the packing sleeve.

[0040] Figure 14 A schematic diagram of a second valve assembly in a fluid end according to an embodiment of the present disclosure is provided.

[0041] Figure 15 A schematic diagram of a valve box on the discharge side of a fluid end according to an embodiment of the present disclosure.

[0042] Figure 16 A schematic diagram of a sealing structure on the discharge side of a hydraulic end provided in an embodiment of the present disclosure.

[0043] Figure 17 A schematic diagram of a valve box on the suction side of a fluid end provided in an embodiment of the present disclosure.

[0044] Figure 18 A schematic diagram of a sealing structure on the suction side of a hydraulic end provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0045] To make the purpose, technical solutions, and advantages of the embodiments of the present disclosure more clear, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0046] Unless otherwise defined, the technical or scientific terms used in this disclosure should have the usual meanings understood by persons of ordinary skill in the field to which this disclosure belongs. The words "first", "second" and similar terms used in this disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "include" or "comprise" mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connect" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0047] As a key piece of equipment in fracturing operations, the plunger pump primarily converts fracturing fluid at atmospheric pressure and a certain viscosity into high-pressure, high-flow fracturing fluid for injection into the formation. Its performance directly impacts the technical level of fracturing operations in oil and gas fields. Currently, fracturing pumps, both domestically and internationally, typically utilize reciprocating horizontal multi-cylinder plunger pumps, such as triplex and quintuplex models. These pumps typically consist of a hydraulic end and a power end. The hydraulic end converts mechanical energy into pressure energy from the working fluid. The power end transfers the kinetic energy of the prime mover to the hydraulic end via a reduction gear system and a crank-connecting rod mechanism.

[0048] Figure 1 A cross-sectional view of a plunger pump. Figure 2 for Figure 1 Schematic diagram of the hydraulic end of the plunger pump shown. Figure 3 for Figure 2 Schematic diagram of the valve box in the hydraulic end shown in FIG. Figure 1 As shown, the plunger pump 003 includes a power end 002 and a fluid end 001. Figure 1 and Figure 2 As shown, the hydraulic end 001 mainly includes a valve box 01, a plunger 02, a valve assembly 03, a valve assembly 04, a sealing element, a pressure cover 05 and a pressure cap 06. Figure 1 Also shown are the clamp 07, the pull rod 08, the cross head 09, the connecting rod 010, the housing 011, and the crankshaft 012. Figure 2 As shown, the hydraulic end 001 also includes a valve seat 021, a spring 022, a suction gland 023, a suction cap 024, a spring 025, a drain hole 026, a sealing packing assembly 027, and a packing cap 028. Figure 3 The cross-intersecting structure of the valve box 01 is shown.

[0049] like Figure 1 and Figure 2 As shown, the operating principle of a plunger pump is as follows: Driven by the prime mover, crankshaft 012 at power end 002 rotates, driving connecting rod 010 and crosshead 09 in horizontal reciprocating motion. Crosshead 09 then drives plunger 02 in horizontal reciprocating motion within valve housing 01 via tie rod 08. During the return stroke of plunger 02, the internal volume of valve housing 01 gradually increases, creating a partial vacuum. Valve assembly 03 opens, valve assembly 04 closes, and the medium enters the inner chamber of valve housing 01. When plunger 02 reaches its return limit, the inner chamber of valve housing 01 is filled with the medium, completing the suction process. During the forward stroke of plunger 02, the internal volume of valve housing 01 gradually decreases, squeezing the medium and increasing its pressure. Valve assembly 04 opens, valve assembly 03 closes, and under pressure, the medium enters drain hole 026. When plunger 02 reaches its forward limit, the medium-holding space within valve housing 01 is minimized, completing the discharge process. As the plunger 02 continuously reciprocates, the suction and discharge processes are performed alternately, and the high-pressure medium is continuously output.

[0050] refer to Figures 1 to 3 , the valve box of the hydraulic end is usually a cross-intersecting structure, such as Figure 3 As shown, the inner cavity of the valve box 02 is divided into a low-pressure chamber 01a, an alternating chamber 01b, and a high-pressure chamber 01c according to the pressure. However, the intersection line is located in the alternating chamber 01b. Mechanical analysis shows that the stress concentration at the intersection line is obvious. Coupled with the effect of the alternating load, fatigue cracks are easily generated at the intersection line, causing the valve box 01 to crack and leak. The valve box needs to be replaced frequently on site, and the replacement cost is high, which is time-consuming and labor-intensive.

[0051] As fracturing construction becomes increasingly difficult (as reflected by higher working pressure), large displacement per unit has become an urgent market demand. If the stress concentration effect at the intersection is not effectively improved, the life of the valve box will be difficult to increase.

[0052] Embodiments of the present disclosure provide a hydraulic end with a T-shaped valve manifold and a plunger pump incorporating the same, thereby extending the service life of the valve manifold. Embodiments of the present disclosure also provide a hydraulic end with two sets of pressure-bearing components on the suction side and a plunger pump incorporating the same, thereby facilitating maintenance and extending the service life of the valve manifold.

[0053] The following introduces the hydraulic end and plunger pump provided in the embodiments of the present disclosure.

[0054] Figure 4 A schematic diagram of a hydraulic end provided in accordance with an embodiment of the present disclosure. Figure 5 A schematic diagram of various areas of an inner cavity in a valve box of a hydraulic end provided in an embodiment of the present disclosure. Figure 6 A schematic diagram of a valve box of a fluid end provided in accordance with an embodiment of the present disclosure. Figure 7 A perspective view of a fluid end provided for an embodiment of the present disclosure. Figure 8 A schematic diagram of another valve box of a hydraulic end provided in an embodiment of the present disclosure. Figure 9 A schematic diagram of the intersection of the inner cavities of a valve box in a hydraulic end provided in an embodiment of the present disclosure. Figure 9 (a) is a cross-sectional view of the inner cavity of the valve box along the XY plane. Figure 9 (b) is a schematic diagram of the YZ plane of the inner cavity of the valve box. Figure 10 A schematic diagram of the intersection of the inner cavities of another valve box in a fluid end provided in an embodiment of the present disclosure. Figure 10 (a) is a cross-sectional view of the inner cavity of the valve box along the XY plane. Figure 10 (b) is a schematic diagram of the YZ plane of the inner cavity of the valve box. Figure 7 The directions X, Y, and Z are shown. For example, the X direction is the extending direction of the first axis A1 mentioned later, and the Y direction is the extending direction of the second axis A2 mentioned later. Figure 11 A cross-sectional view of a fluid end provided in accordance with an embodiment of the present disclosure. Figure 12 for Figure 11 Schematic diagram of the valve box of the hydraulic end is shown.

[0055] Figure 13A for Figure 11 A partial schematic diagram of the leakage channel in the valve box. Figure 13B for Figure 11 A partial schematic diagram of the packing sleeve in the valve box and the pressure relief area of ​​the packing sleeve.

[0056] like Figure 11 As shown, an embodiment of the present disclosure provides a hydraulic end, comprising: a valve box 70, a first valve assembly V1, a first pressure-bearing assembly M1, and a second pressure-bearing assembly M2.

[0057] like Figure 11 、 Figure 5 as well as Figure 6 As shown, the valve box 70 includes an inner chamber 07 , and the inner chamber 07 includes an alternating chamber 07 b and a low-pressure chamber 07 a .

[0058] like Figure 11 and Figure 5As shown, the first valve assembly V1 is configured to open to connect the low-pressure chamber 07a and the alternating chamber 07b or to close to separate the low-pressure chamber 07a and the alternating chamber 07b. The area of ​​the inner chamber 07 located between the first valve assembly V1 and the second pressure-bearing assembly M2 is the low-pressure chamber 07a.

[0059] like Figure 11 As shown, the first pressure-bearing component M1 is in contact with the first valve component V1.

[0060] like Figure 11 As shown, the second pressure-bearing component M2 and the first pressure-bearing component M1 are arranged in sequence along the extension direction of the first axis A1 of the inner cavity 07.

[0061] like Figure 11 As shown, the first valve assembly V1 , the first pressure-bearing assembly M1 and the second pressure-bearing assembly M2 are sequentially arranged along the extension direction of the first axis A1 of the inner cavity 07 .

[0062] Figure 11 and Figure 4 The suction side 70a, discharge side 70b, and plunger side 70c of the fluid end are shown.

[0063] The hydraulic end provided by the embodiment of the present disclosure is provided with two sets of pressure-bearing components on the suction side 70a, that is, a first pressure-bearing component M1 and a second pressure-bearing component M2. The first valve component V1 is connected to the valve box 70 through the first pressure-bearing component M1, rather than directly "sitting" on the valve box 70. The first valve component V1 is not in direct contact with the valve box, which facilitates maintenance and helps to extend the service life of the valve box.

[0064] For example, Figure 11 As shown, the first pressure-bearing assembly M1 is detachably connected to the valve box 70 , and the second pressure-bearing assembly M2 is detachably connected to the valve box 70 , so as to facilitate the removal of the plunger 81 from the suction side 70 a .

[0065] For example, Figure 11 As shown, the first pressure-bearing assembly M1 includes an alternating pressure cover 13 and an alternating pressure cap 23 . The alternating pressure cover 13 is closer to the first valve assembly V1 than the alternating pressure cap 23 . The alternating pressure cap 23 is connected to the valve box 70 via threads.

[0066] For example, the alternating pressure cover 13 bears the alternating load, and the alternating pressure cap 23 bears the alternating load. The alternating pressure cover 13 can also be called an intermediate pressure cover or directly a pressure cover, and the alternating pressure cap 23 can also be called an intermediate pressure cap or directly a pressure cap.

[0067] For example, Figure 11 As shown, the maximum length of the alternating pressure cover 13 on the first axis A1 is smaller than the maximum length of the alternating pressure cap 23 on the first axis A1.

[0068] In the hydraulic end provided in the embodiment of the present disclosure, the first valve assembly V1 is not directly "seated" on the valve box 70, but is indirectly connected to the valve box 70 via the alternating pressure cover 13. The alternating pressure cover 13 will move when subjected to force, so an alternating pressure cap 23 is required to fix and limit it. For example, the alternating pressure cap 23 contacts the alternating pressure cover 13, and the alternating pressure cap 23 and the valve box 70 are fastened by threads, but this is not limited to this. When the alternating pressure cover 13 is subjected to an alternating load, the load will be transferred to the threads of the alternating pressure cap 23. Because the contact area between the alternating pressure cover 13 and the alternating pressure cap 23 is small, and the threads of the alternating pressure cap 23 are long, finite element analysis shows that the stress at the threads of the alternating pressure cap 23 is less than the stress at the threads of the pressure cap of a conventional hydraulic end. The hydraulic end provided in the embodiment of the present disclosure can extend the service life of the valve box 70.

[0069] For example, Figure 11 and Figure 13A As shown, a first sealing structure SE is provided between the alternating pressure cover 13 and the valve housing 70. The valve housing 70 has a leakage channel 7000. The leakage channel 7000 is configured to allow fluid to flow when the first sealing structure SE at least partially fails. Of course, in other embodiments, the leakage channel 7000 may not be provided in the valve housing of the hydraulic end.

[0070] For example, Figure 11 、 Figure 12 and Figure 13A As shown, the leakage channel 7000 passes through the body 100 of the valve box 70. The leakage channel 7000 leads from the outside of the body 77 of the valve box to the inner cavity 07.

[0071] For example, Figure 11 、 Figure 12 and Figure 13A As shown, in order to facilitate manufacturing and make the valve box have higher strength, the leakage channel 7000 is inclined relative to the first axis A1 of the inner cavity 07, and the acute angle θa formed by the leakage channel 7000 and the first axis A1 of the inner cavity 07 is greater than or equal to 30 degrees and less than or equal to 60 degrees.

[0072] For example, Figure 11 、 Figure 12 and Figure 13A As shown, the end of the leakage channel 7000 away from the inner cavity 07 is closer to the suction side 70a than the end of the leakage channel 7000 close to the inner cavity 07. Figure 11 As shown, the end of the leakage channel 7000 away from the inner cavity 07 is further to the right than the end of the leakage channel 7000 close to the inner cavity 07.

[0073] For example, Figure 11 and Figure 13AAs shown, the first sealing structure SE includes a first seal SE1 and a second seal SE2, and the end of the leakage channel 7000 close to the alternating pressure cover 13 is located between the first seal SE1 and the second seal SE2. For example, the first seal SE1 includes a sealing ring, and the second seal SE2 includes a sealing ring.

[0074] like Figure 11 and Figure 13A As shown, the sealing groove of the first sealing structure SE is provided in the alternating pressure cover 13. In other embodiments, the sealing groove of the first sealing structure SE may also be provided in the valve box 70.

[0075] For example, Figure 4 、 Figure 11 As shown, the first valve assembly V1 includes a valve body 1a, a sealing member 1b and a valve seat 1c, and an alternating pressure cover 13 serves as a base of the valve seat 1c.

[0076] For example, Figure 4 、 Figure 11 As shown, the first valve assembly V1 further includes a spring 1d and a spring support 1e.

[0077] For example, Figure 4 、 Figure 11 As shown, the spring support 1e includes a hollow structure e0 and is positioned relative to the valve housing 70 via an inclined surface S01. The hollow structure e0 facilitates smooth liquid flow, and the inclined surface S01 prevents the spring support 1e from swaying within the horizontal cavity of the valve housing 70. The horizontal cavity of the valve housing also has an inclined surface that mates with the inclined surface of the spring support 1e, ensuring contact between the spring support 1e and the valve housing 70.

[0078] For example, Figure 4 、 Figure 11 As shown, the sealing member 1b is embedded in the valve body 1a. When the first valve assembly V1 is opened, the valve body 1a embedded with the sealing member 1b moves to the left, and the low-pressure chamber 07a and the alternating chamber 07b are connected.

[0079] For example, Figure 4 、 Figure 5 、 Figure 6 、 Figure 8 and Figure 11 As shown, the valve box 70 has an upper liquid hole 700. Figure 4 、 Figure 5 、 Figure 6 and Figure 11 A single-sided upper liquid port is shown. Figure 8The valve box 700 is shown with two liquid supply holes 700: upper liquid hole 700a and upper liquid hole 700b. Liquid supply can be provided on either one side or on both sides. For example, single-side supply can meet the needs of small-volume and low-slurry operations without sand plugging. Double-side supply can meet the needs of large-volume and high-slurry operations. Double-side supply holes ensure stable liquid supply and reduce the risk of sand plugging.

[0080] For example, Figure 11 and Figure 13A As shown, the alternating pressure cover 13 has a low-pressure fluid passage 130, which is communicated with the upper liquid hole 700 of the valve box 70. The low-pressure fluid passage 130 may also be referred to as a first passage 130.

[0081] For example, Figure 11 and Figure 13A As shown, the alternating pressure cap 23 has a low-pressure fluid passage 230, which is in communication with the upper liquid hole 700 of the valve box 70. The low-pressure fluid passage 230 may also be referred to as a second passage 230.

[0082] For example, Figure 11 As shown, the second pressure-bearing assembly M2 includes a suction gland 33 and a suction cap 43. The suction gland 33 is closer to the first pressure-bearing assembly M1 than the suction cap 43. The suction cap 43 is connected to the valve box 70 through threads.

[0083] For example, Figure 11 As shown, the first pressure-bearing assembly M1 and the second pressure-bearing assembly M2 are respectively arranged on opposite sides of the upper liquid hole 700. For example, Figure 11 As shown, the first pressure-bearing assembly M1 and the second pressure-bearing assembly M2 are respectively arranged on both sides of the upper liquid hole 700 in the extension direction of the first axis A1. Figure 11 As shown, the first pressure-bearing component M1 is on the left side of the upper liquid hole 700 , and the second pressure-bearing component M2 is on the right side of the upper liquid hole 700 .

[0084] For example, Figure 11 As shown, the alternating pressure cover 13 and the suction pressure cover 33 are respectively arranged on opposite sides of the alternating pressure cap 23. For example, Figure 11 As shown, the alternating pressure cap 23 and the suction pressure cap 33 are respectively arranged on opposite sides of the upper liquid hole 700. Figure 11 As shown, the alternating pressure cap 23 is arranged on the left side of the upper liquid hole 700 , and the suction pressure cover 33 is arranged on the right side of the upper liquid hole 700 .

[0085] Figure 4 The first valve assembly V1 of the hydraulic end shown includes a base 1f. Figure 11 The alternating pressure cover 13 in the hydraulic end shown is used as the first valve assembly V1 including a base, making the structure of the hydraulic end more compact. Figure 4The base 1 f shown has a low-pressure liquid passage 330 , which is communicated with the upper liquid hole 700 of the valve box 70 .

[0086] For example, Figure 4 、 Figure 5 、 Figure 6 and Figure 11 As shown, the inner chamber 07 has an inverted T-shaped structure. The alternating chamber 07b and the high-pressure chamber 07c are arranged along the extension direction of the second axis A2 of the inner chamber 07. The first axis A1 intersects the second axis A2. Therefore, the hydraulic end includes the inverted T-shaped inner chamber 07, and the valve box 70 can be referred to as a T-shaped valve box. The embodiments of this disclosure are described using the example where the first axis A1 and the second axis A2 are perpendicular.

[0087] For example, Figure 4 and Figure 11 As shown, the hydraulic end further includes a second valve assembly V2, and the inner cavity 07 further includes a high-pressure cavity 07c. The second valve assembly V2 is configured to open to connect the alternating cavity 07b and the high-pressure cavity 07c or to close to separate the alternating cavity 07b and the high-pressure cavity 07c.

[0088] For example, Figure 4 and Figure 11 As shown, the second valve assembly V2 includes a valve body 2a, a sealing member 2b (for sealing), a valve seat 2c, a spring 2d and a base 2f.

[0089] For example, Figure 4 and Figure 11 As shown, the sealing member 2b is embedded in the valve body 2a. When the second valve assembly V2 is opened, the valve body 2a embedded with the sealing member 2b moves upward, and the high-pressure chamber 07c and the alternating chamber 07b are connected.

[0090] like Figure 4 and Figure 11 As shown, the second valve assembly V2 is close to the discharge hole 7005, opens when the plunger advances, and circulates high-pressure liquid; the first valve assembly V1 is close to the upper liquid hole 700, opens when the plunger returns, and circulates low-pressure liquid; the base 2f of the second valve assembly V2 is directly embedded in the valve box 70, and its hardness is greater than that of the valve box 70, which prevents damage to the valve box 70 during opening and closing (when slapping), thereby extending the service life of the valve box 70.

[0091] For example, Figure 4 and Figure 11 As shown, the hydraulic end also includes a third pressure-bearing assembly M3, which is located in the inner cavity. The third pressure-bearing assembly M3 and the second valve assembly V2 are arranged in sequence along the extension direction of the second axis A2. The area of ​​the inner cavity O7 between the second valve assembly V2 and the third pressure-bearing assembly M3 is the high-pressure chamber O7c.

[0092] like Figure 4and Figure 11 As shown, the third pressure-bearing assembly M3 includes a pressure cover 40 and a pressure cap 50. The pressure cover 40 can be referred to as a discharge pressure cover 40, and the pressure cap 50 can be referred to as a discharge pressure cap 50.

[0093] For example, Figure 4 and Figure 11 As shown, the upper liquid hole 700 and the high-pressure chamber 07c are staggered in the extension direction of the first axis A1.

[0094] For example, Figure 4 、 Figure 6 and Figure 11 As shown, the intersection of inner cavity 07 includes a first sub-cavity 071 and a second sub-cavity 072. First sub-cavity 071 and second sub-cavity 072 are arranged along the extension direction of second axis A2. Second sub-cavity 072 is closer to the portion of inner cavity 07 extending along first axis A1 (horizontal cavity) than first sub-cavity 071. To reduce stress concentration, the maximum dimension h2 of second sub-cavity 072 along the extension direction of second axis A2 is greater than the maximum dimension h1 of first sub-cavity 071 along the extension direction of second axis A2. No second valve assembly V2 is placed in first sub-cavity 071 or second sub-cavity 072. Second valve assembly V2 is located outside first sub-cavity 071 or second sub-cavity 072. First sub-cavity 071 or second sub-cavity 072 may be hollow cavities solely for fluid circulation.

[0095] For example, Figure 4 and, Figure 6 and Figure 11 As shown, to reduce stress concentration, the dimension D1 of the second subcavity 072 in the extension direction of the first axis A1 gradually increases from a position away from the first axis A1 to a position close to the first axis A1. That is, the dimension D1 of the second subcavity 072 in the extension direction of the first axis A1 gradually increases from top to bottom.

[0096] For example, Figure 4 、 Figure 6 and Figure 11 As shown, the angle between the portion of the valve box 70 used to form the second sub-cavity 072 and the first axis A1 is 30-80 degrees. For further example, the angle between the portion of the valve box 70 used to form the second sub-cavity 072 and the first axis A1 is 30-60 degrees.

[0097] For example, Figure 4 and Figure 11 As shown, the first sub-cavity 071 is a cylindrical cavity, but is not limited thereto. Figure 11 As shown, the second sub-cavity 072 is a truncated cone-shaped cavity, but is not limited thereto.

[0098] For example, Figure 4 and Figure 11As shown, the valve box 70 is provided with a protective sleeve 73 at positions corresponding to the first sub-cavity 071 and the second sub-cavity 072. The protective sleeve 73 is provided at the "bell mouth" of the inner cavity 07 of the valve box 70 to protect the inner cavity 07 and extend the service life of the valve box 70.

[0099] For example, Figure 4 and Figure 11 As shown, the valve box 70 is formed into a bell-mouth shape at the intersection 7006 of the inner cavity 07 by processing. For example, the bell-mouth shape can be processed by boring, but is not limited to this.

[0100] For example, Figure 4 and Figure 11 As shown, a protective sleeve 73 is provided at the "bell mouth" of the inner cavity of the valve box 70 to prevent wear of the inner cavity. When the inner cavity is worn, its surface roughness increases. Combined with high-pressure operation, fatigue cracks are very likely to form on the surface. Therefore, the combined (cooperative) protection of the "bell mouth" and protective sleeve 73 at the intersection can reduce the risk of cracking and extend the service life of the valve box. For example, the protective sleeve 73 can be installed into the interior of the valve box by cold installation, but this method is not limited to cold installation. The protective sleeve 73 can also be installed by machining or hot working.

[0101] Figure 9 and Figure 10 The bell mouth 76, the horizontal cavity 0701, and the body 77 of the valve box 70 are shown.

[0102] The inner cavity of the valve box of the hydraulic end provided in the embodiment of the present disclosure is a T-shaped structure, and the intersection position is designed to be in a "bell mouth" form to alleviate the problem of stress concentration at the intersection line of the inner cavity.

[0103] For example, Figure 6 and Figure 11 As shown, 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 is an inverted T-shaped structure, the alternating chamber 07b and the low-pressure chamber 07a are arranged along the extension direction of the first axis A1 of the inner chamber 07, and the alternating chamber 07b and the high-pressure chamber 07c are arranged along the extension direction of the second axis A2 of the inner chamber 07, and the first axis A1 intersects the second axis A2. Figure 6 The first axis A1 and the second axis A2 of the inner cavity 07 are shown. Figure 6 and Figure 12 As shown, the inner cavity 07 includes a horizontal cavity 0701 and a vertical cavity 0702 .

[0104] For example, Figure 6 and Figure 11As shown, the inner cavity of the valve box 70 is a T-shaped structure. According to the installation positions of the first valve assembly and the second valve assembly, the inner cavity 07 is divided into a low-pressure cavity 07a, an alternating cavity 07b and a high-pressure cavity 07c. The intersection of the inner cavity 07 is designed to be in a "bell-mouth" form, and the transition is smooth, which can effectively improve the stress concentration effect.

[0105] Compared with a conventional valve box of a hydraulic end, the structure of the valve box of the hydraulic end provided in the embodiments of the present disclosure has the following features.

[0106] 1) The stress concentration effect in the inner cavity is significantly improved.

[0107] The inner cavity of the cross-intersecting structure is as follows Figure 3 As shown in the figure, the intersections include positions Pa, Pb, Pc, and Pd. The stress concentration points are at positions Pc and Pd. From a mechanical analysis, the stress concentration is very obvious, which is prone to initiation of fatigue cracks, leading to cracking of the valve box.

[0108] The embodiment of the present disclosure provides a valve box in the hydraulic end where the inner cavities intersect, and there is no right angle. The transition at the intersection of the inner cavities is smooth, and the design is optimized at the position where stress concentration is most likely to occur. The intersection is in a bell-mouth shape and has no stress concentration point. From a mechanical analysis, the stress concentration effect is significantly improved.

[0109] 2) Simple structure and strong sealing.

[0110] The valve box in a typical hydraulic end is a split structure. The packing cavity, suction chamber (low-pressure chamber), and discharge chamber (high-pressure chamber) are bolted to the main body of the valve box. This structure is relatively complex and requires multiple seals, which invisibly increases the number of leaks. The sealing surface machining requires high precision, but the more sealing surfaces, the more labor required, the lower the machining efficiency, and ultimately cannot guarantee a complete seal.

[0111] The valve box in the hydraulic end provided by the embodiment of the present disclosure is an integral structure, which is tightly sealed and resistant to high pressure, uses fewer seals and does not require bolts, has a simple and compact structure, and has a low risk of valve box leakage.

[0112] 3) Easy maintenance.

[0113] The axis of the plunger in a typical hydraulic end is not collinear with the axis of the valve box, and the plunger cannot be pulled out from the suction side. When the plunger is damaged or the packing pack assembly needs to be replaced, the entire hydraulic end needs to be removed. Since the hydraulic end is heavy, a crane will be used to assist during the process, which greatly reduces the efficiency of maintenance. During the actual fracturing operation, the client will not leave a long time to replace the accessories. In some common hydraulic ends, although the axis of the plunger is collinear with the axis of the horizontal cavity of the valve box, there will be many inconveniences during maintenance. For example, when maintaining the plunger or the packing pack assembly, the plunger has a large diameter and cannot be pulled out from the inner cavity of the valve box. The entire hydraulic end needs to be disassembled for maintenance. Even if the plunger has a small diameter and can be pulled out from the inner cavity of the valve box, the suction side also needs to be removed before maintenance can be performed.

[0114] The hydraulic end provided by the embodiment of the present disclosure does not have the above-mentioned maintenance inconvenience problem. The axis of the plunger coincides with the first axis (horizontal axis) of the valve box, and the first pressure-bearing component M1 and the second pressure-bearing component M1 are provided on the suction side. The axis of the first pressure-bearing component M1 and the axis of the second pressure-bearing component M1 both coincide with the axis of the plunger. During maintenance, normal operations at the well site can be followed.

[0115] For example, the most efficient routine operation for maintaining a plunger or packing pack assembly at a well site is: remove the pressure cap on the suction side, open the horizontal cavity of the valve box, remove the clamp, "disconnect" the hydraulic end from the power end, use a pulling tool to pull the plunger out from the suction side along the axis of the horizontal cavity of the valve box, and perform normal maintenance. After maintenance, reverse the above steps to restore the accessories. The entire maintenance process does not require the hydraulic end to be removed from the plunger pump.

[0116] For example, Figure 4 and Figure 11 As shown, the alternating pressure cover 13 is a rotating body structure, which is placed horizontally inside the valve box 70, with the left side in contact with the first valve assembly V1 and the right side in contact with the alternating pressure cap 23. The alternating pressure cap 23 and the valve box 70 are threadedly matched.

[0117] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the hydraulic end includes a plunger 81. The plunger 81 is a rotating body, one end of the plunger 81 contacts the liquid inside the valve box 70 and reciprocates, and the other end is connected to the power end of the plunger pump through a clamp 86.

[0118] For example, Figures 5 and 6 、 Figure 12 and Figure 13B As shown, the inner cavity 09 further includes a plunger cavity 07d, which is configured to accommodate a plunger 81. Figure 12 As shown, the plunger chamber 07d, the alternating chamber 07b, and the low-pressure chamber 07d are sequentially arranged along the extension direction of the first axis A1 of the inner chamber 07.

[0119] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the hydraulic end further includes a packing pack assembly 82 , and the packing pack assembly 82 includes a packing pack 821 , a spacer ring 822 , and a pressure ring 823 .

[0120] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the packing package 821 includes three packing rings. Of course, the number of packing rings is not limited to that shown in the figure and can be determined according to needs. For example, the material of the packing rings includes rubber, but is not limited thereto.

[0121] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the plunger side 70c of the valve box 70 is provided with a lubricating oil channel 7007 for lubricating the packing pack 821 (rubber part) to make the reciprocating motion of the plunger 81 smoother; the plunger 81 is wrapped with the packing pack 821 in the circumference, and the packing pack 821 acts as a seal to prevent liquid leakage when the plunger 81 reciprocates.

[0122] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the inner wall of the packing packing 821 has an interference fit with the plunger 81, which acts as a seal. When the plunger 81 reciprocates, it rubs against the inner wall of the packing packing 821. Forced lubrication here can reduce friction.

[0123] For example, a pulling hole (bolt hole) is provided at the front end of the plunger 81 and is equipped with a pulling tool. During maintenance, the clamp 86 is first removed and disconnected from the power end, and the plunger 81 is pulled out from the suction side 70a along the first axis A1 of the valve box 70 by the pulling tool.

[0124] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the fluid end further includes a packing press cap 83 , which is configured to apply pressure to the packing pack assembly 82 .

[0125] For example, Figure 4 、 Figure 11 and Figure 13BAs shown, packing pack 821 is secured by a packing cap 83, which is threadedly connected to valve housing 70. Packing cap 83 prevents axial movement of packing pack 821 during reciprocating motion of plunger 81 and expands packing pack 821 by tightening and squeezing, facilitating sealing. Packing pack 821 is provided with a spacer ring 822 and a pressure ring 823 at each end. Spacer ring 822 isolates packing pack 821 from valve housing 70, while pressure ring 823 isolates packing pack 821 from packing cap 83, protecting packing pack 821 and extending its service life. For example, spacer ring 822 and pressure ring 823 may be metal.

[0126] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the hydraulic end further includes a packing sleeve 84 and a packing sleeve pressure cap 85 . The plunger cavity 07 d is configured to accommodate the plunger 81 . The packing sleeve 84 is located between the packing bag assembly 82 and the valve box 70 . The packing sleeve pressure cap 85 is configured to apply pressure to the packing sleeve 84 .

[0127] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the packing sleeve 84 is axially limited by the shoulder and the packing sleeve pressing cap 85.

[0128] For example, at least one of the packing 84 and the packing pressure cap 85 is connected to the valve box 70 by welding.

[0129] For example, the hardness of the packing 84 is greater than that of the valve box 70. Since the hardness of the packing 84 is higher than that of the valve box 70, when the valve box 70 is damaged, the packing 84 will not be damaged. Therefore, the packing 84 and the valve box 85 can be fixed by welding.

[0130] For example, Figure 4 、 Figure 11 and Figure 13B As shown, the outer diameter of packing pack 821 contacts packing sleeve 84, while the inner diameter of packing pack 821 contacts plunger 81. A seal 7008 is provided at the front end of packing sleeve 84 to prevent high-pressure liquid from entering the gap, causing leakage and damaging the valve box. Packing sleeve 84 is a wear-resistant component and has an interference fit with valve box 70. The hardness of packing sleeve 84 is higher than that of the valve box. Packing sleeve 84 is provided to prevent damage to valve box 70 caused by friction from packing pack 821, thereby extending the service life of the valve box.

[0131] For example, the inner and outer diameters of the packing sleeve pressure cap 85 are both provided with threads, the outer threads of the packing sleeve pressure cap 85 cooperate with the valve box 70, and the inner threads of the packing sleeve pressure cap 85 cooperate with the packing pressure cap 83. In order to prevent the packing sleeve pressure cap 85 from loosening during the reciprocating motion of the plunger 81, the packing sleeve pressure cap 85 can be fixed to the valve box 70 by welding.

[0132] Figure 4 、 Figure 6 、 Figure 7 and Figure 11 Also shown is the discharge side 70b of the fluid end. Figure 11 and Figure 7 As shown, the valve box 70 has an upper liquid hole 700 on the suction side 70a and a discharge hole 7005 on the discharge side 70b. For example, the upper liquid hole 700 is connected to the upper water manifold to circulate low-pressure liquid; the discharge hole 7005 can be connected to a discharge flange to circulate high-pressure liquid.

[0133] For example, Figure 4 、 Figure 6 and Figure 11 As shown, the valve housing 70 is provided with suction-side threads 7001, discharge-side threads 7002, and plunger-side threads 7003. The suction pressure cap 43 is connected to the valve housing 70 via the suction-side threads 7001. The pressure cap 50 is connected to the valve housing 70 via the discharge-side threads 7002. The packing sleeve pressure cap 85 is connected to the valve housing 70 via the plunger-side threads 7003.

[0134] For example, the first valve assembly V1 and the second valve assembly V2 are both one-way valves. Figure 11 As shown, the first valve assembly V1 and the second valve assembly V2 can be interchangeable. For example, the second valve assembly V2 is placed vertically and the first valve assembly V1 is placed horizontally, and the axes of the first valve assembly V1 and the second valve assembly V2 are perpendicular to each other.

[0135] like Figure 11 As shown, for the first valve assembly V1, the valve seat 1c is positioned in the valve seat groove of the alternating pressure cover 13. The left side of the alternating pressure cover 13 serves as a base for the valve seat 1c, securing it. For example, the alternating pressure cover 13, together with the valve body 1a, seal 1b, spring 1d, and spring support 1e, forms a one-way valve. For example, the axis of the first valve assembly V1 coincides with the axis of the alternating pressure cover 13. When the plunger is in the return stroke, the valve body 1a opens, allowing low-pressure liquid to enter the valve housing 70. When the plunger is in the forward stroke, the valve body 1a closes, preventing low-pressure liquid from entering the valve housing 70.

[0136] For example, reference Figure 11 Taking the fluid entering the hydraulic end as fracturing fluid as an example, the working principle of the hydraulic end is as follows.

[0137] When absorbing liquid, the plunger 81 returns (moves horizontally to the left), the first valve assembly V1 opens, and the second valve assembly V2 closes. The fracturing fluid flows from the suction manifold through the upper liquid hole 700, the low-pressure fluid channel 230, and the low-pressure fluid channel 130 into the alternating chamber 07b until the alternating chamber 07b is filled with fracturing fluid. At this time, the liquid in the inner chamber 07 is a low-pressure liquid.

[0138] When discharging the liquid, the plunger 81 moves (translates to the right), the first valve assembly V1 is closed, the second valve assembly V2 is opened, and the fracturing fluid flows from the alternating chamber 07b into the high-pressure chamber 07c and is discharged through the discharge hole 7005. At this time, the liquid in the inner chamber 07 is a high-pressure liquid.

[0139] Figure 14 Schematic diagram of a second valve assembly in a fluid end provided in an embodiment of the present disclosure. Figure 14 As shown, the valve body 2a includes a boss a1 and a claw a2. The function of the boss a1 includes limiting the spring 2d to prevent the spring 2d from moving radially. The function of the boss a1 also includes limiting the opening height of the valve body 2a. 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 to achieve uniform opening height each time.

[0140] like Figure 14 As shown, the inner hole of the base 2f is in clearance fit with the claw a2, which guides the claw a2 and prevents the valve body 2a from deflecting under the impact of high-pressure liquid; the valve seat 2c and the base 2f are split structures, and the hardness of the base 2f is higher than that of the base 2f, so as to prevent the inclined surface of the valve seat 2c from wearing when the valve body 2a hits the valve seat 2c, avoid wearing the valve seat 2c and causing poor sealing, and also avoid reducing the service life of the valve seat and valve body.

[0141] The structure and function of the first valve assembly can be referred to the above description. The difference is that the boss of the valve body 1a is in rigid contact with the boss of the spring support.

[0142] Figure 15 A schematic diagram of a valve box on the discharge side of a fluid end according to an embodiment of the present disclosure. Figure 16 A schematic diagram of a sealing structure on the discharge side of a hydraulic end provided in an embodiment of the present disclosure. Figure 17 A schematic diagram of a valve box on the suction side of a fluid end provided in an embodiment of the present disclosure. Figure 18 A schematic diagram of a sealing structure on the suction side of a hydraulic end provided in an embodiment of the present disclosure.

[0143] Figure 14 The sealing member 1021 is shown, and the sealing member 1021 includes a sealing ring and a sealing groove is provided at a corresponding position of the base 2f. Figure 10 and Figure 11 As shown, a sealing member 1021 is provided to achieve sealing between the second valve assembly V2 and the valve box 70 .

[0144] Figure 15 A sealing groove 901 is shown, Figure 16 Shown is a seal 902. The seal 902 is provided to achieve sealing of the high pressure chamber of the inner chamber.

[0145] Figure 17 A sealing groove 903 is shown, Figure 18 Shown is a seal 904. The seal 904 is provided to seal the low pressure chamber of the inner cavity.

[0146] For example, in an embodiment of the present disclosure, 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 can change alternately.

[0147] The hydraulic end provided by the embodiments of the present disclosure has at least one of the following effects.

[0148] 1) The stress concentration effect in the inner cavity is significantly improved.

[0149] The embodiment of the present disclosure provides a valve box at the hydraulic end, in which there are no right angles at the intersection of the inner cavities, and the transition at the intersection of the inner cavities is smooth. The shape design is carried out at the position where stress concentration is most likely to occur. The intersection is in the shape of a bell mouth and there is no stress concentration point. From a mechanical analysis, the stress concentration effect is significantly improved.

[0150] 2) Simple structure and strong sealing.

[0151] The valve box of the hydraulic end provided in the embodiment of the present disclosure is an integral structure, which is tightly sealed and resistant to high pressure, uses fewer seals and does not require bolts, has a simple and compact structure, and has a low risk of valve box leakage.

[0152] 3) Easy maintenance.

[0153] In the hydraulic end provided by the embodiment of the present disclosure, the axis of the plunger coincides with the first axis (horizontal axis) of the valve box, and there is a pressure cap on the suction side (the axis of the pressure cap coincides with the axis of the plunger, and the pressure cap is detachable). During maintenance, normal operations at the well site can be followed.

[0154] In the hydraulic end provided in the embodiment of the present disclosure, Figure 4 and Figure 11 The hydraulic end includes a T-type valve box, Figure 11 The hydraulic end is shown to include two sets of pressure-bearing components. It should be noted that in a hydraulic end with two sets of pressure-bearing components, a T-type valve box may not be used; in a hydraulic end with a T-type valve box, two sets of pressure-bearing components may not be used, and the configuration can be adjusted according to needs.

[0155] An embodiment of the present disclosure further provides a plunger pump comprising any of the above-mentioned hydraulic ends.

[0156] For example, the above-mentioned fluid end and plunger pump can be applied to fracturing / cementing equipment in oil and gas fields.

[0157] The above description is merely a specific embodiment of the present disclosure, but the scope of protection of the present disclosure is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this disclosure should be included in the scope of protection of the present disclosure. Therefore, the scope of protection of the present disclosure should be based on the scope of protection of the claims.

Claims

1. A fluid end comprising: The valve box includes an inner cavity, wherein the inner cavity includes an alternating cavity and a low-pressure cavity; a first valve assembly, configured to be opened to connect the low-pressure chamber and the alternating chamber or to be closed to separate the low-pressure chamber and the alternating chamber, the first valve assembly comprising a valve body, a sealing member, a valve seat and a base; A second pressure-bearing component is located in the inner cavity, Wherein, the valve seat, the base and the second pressure-bearing component are sequentially arranged along the extension direction of the first axis of the inner cavity; The device further comprises a second valve assembly and a third pressure-bearing assembly, wherein the inner cavity further comprises a high-pressure cavity, the second valve assembly is configured to be opened to connect the alternating cavity and the high-pressure cavity, or 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 the extending direction of the second axis of the inner cavity, the 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 with the second axis; 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 extension direction of the second axis, the second sub-cavity is closer to the portion of the inner cavity extending along the first axis than the first sub-cavity, and the maximum dimension of the second sub-cavity in the extension direction of the second axis is greater than the maximum dimension of the first sub-cavity in the extension direction of the first axis. The size of the second sub-cavity in the extension direction of the first axis gradually increases from a position away from the first axis to a position close to the first axis; The valve box is formed into a bell-mouth shape at the intersection of the inner cavities by processing, and the valve box is provided with protective sleeves at positions corresponding to the first sub-cavity and the second sub-cavity.

2. The liquid end according to claim 1, wherein: The second pressure-bearing component is detachably connected to the valve box.

3. The liquid end according to claim 1, wherein: The base has a low-pressure liquid channel, and the low-pressure liquid channel is communicated with the upper liquid hole of the valve box.

4. The liquid end according to claim 1, wherein: The valve box has a leakage channel, and the leakage channel runs through the body of the valve box.

5. The liquid end according to claim 1, wherein: The second pressure-bearing component includes a suction gland and a suction cap. The suction gland is closer to the base than the suction cap. The suction cap is connected to the valve box via threads.

6. The liquid end according to claim 5, wherein: The valve seat and the suction gland are respectively arranged on two opposite sides of the base.

7. The liquid end according to claim 1, wherein: The inner cavity is in an inverted T-shaped structure, and the alternating cavity and the high-pressure cavity are arranged along the extension direction of the second axis of the inner cavity.

8. The liquid end according to claim 7, wherein: The valve box has an upper liquid hole, and the upper liquid hole and the high-pressure chamber are staggered in the extending direction of the first axis.

9. The liquid end according to claim 8, wherein: The base 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.

10. The liquid end according to any one of claims 1 to 6, wherein: The first valve assembly includes a spring bracket, which is a hollow structure and is limited by an inclined surface with the valve box.

11. A plunger pump comprising the fluid end according to any one of claims 1 to 10.

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