Hydraulic end and plunger pump

Abstract

A hydraulic end and a piston pump are provided. The hydraulic end includes: a valve box including an inner cavity, the inner cavity including an alternating cavity and a low-pressure cavity; a first valve assembly located in the inner cavity and configured to be opened to communicate the low-pressure cavity and the alternating cavity or configured to be closed to separate the low-pressure cavity and the alternating cavity; a pressure-bearing structural member, at least a part of the pressure-bearing structural member being located in the low-pressure cavity, and a first sealing structure located between the pressure-bearing structural member and the valve box; at least one of the valve box and the pressure-bearing structural member has a bleed channel configured to allow fluid to flow when a part of the first sealing structure fails. The hydraulic end has a bleed channel, creating an artificial leak point. Once the seal fails, it can be quickly and intuitively detected, facilitating timely replacement of accessories and avoiding large leaks in the inner cavity, thus preventing safety accidents.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to a hydraulic end and a piston pump. Background Art

[0002] At present, fracturing construction is the main production-increasing method in the process of oil and gas field exploitation, and the piston pump is the main equipment for pumping fracturing media in the production-increasing operation. In other words, in the entire process of oil and gas exploitation, any process that requires conveying media into the well under a specific pressure needs to be achieved through a piston pump. Summary of the Invention

[0003] Embodiments of the present disclosure provide a hydraulic end and a piston pump. The hydraulic end has a drain channel, creating an artificial leak point. Once the seal fails, it can be quickly and intuitively detected, facilitating timely replacement of accessories and avoiding large-scale leakage in the inner cavity, thus preventing safety accidents.

[0004] Embodiments of the present disclosure provide a hydraulic end, including: a valve box including an inner cavity, the inner cavity including an alternating cavity and a low-pressure cavity; a first valve assembly located in the inner cavity, configured to be opened to communicate the low-pressure cavity and the alternating cavity or configured to be closed to separate the low-pressure cavity and the alternating cavity; a pressure-bearing structural member, at least a part of the pressure-bearing structural member being located in the low-pressure cavity, and a first sealing structure located between the pressure-bearing structural member and the valve box; at least one of the valve box and the pressure-bearing structural member has a drain channel, and the drain channel is configured to allow fluid to flow when a part of the first sealing structure fails.

[0005] For the hydraulic end provided by the embodiments of the present disclosure, the first sealing structure includes a first seal and a second seal, the drain channel includes a first drain port and a second drain port, the first drain port is closer to the first sealing structure than the second drain port, and the first drain port is located between the first seal and the second seal.

[0006] For the hydraulic end provided by the embodiments of the present disclosure, the drain channel is provided in the valve box and is inclined with respect to a first axis of the inner cavity.

[0007] For the hydraulic end provided by the embodiments of the present disclosure, the acute angle formed by the drain 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.

[0008] For the hydraulic end provided by the embodiments of the present disclosure, the pressure-bearing structural member includes a first pressure-bearing assembly and a second pressure-bearing assembly, and the first valve assembly, the first pressure-bearing assembly, and the second pressure-bearing assembly are sequentially arranged along the extending direction of the first axis of the inner cavity.

[0009] According to the hydraulic end provided by the embodiments of the present disclosure, the first pressure-bearing assembly includes an alternating gland and an alternating gland nut, the alternating gland is closer to the first valve assembly than the alternating gland nut, and the alternating gland nut is threadedly connected to the valve box.

[0010] According to the hydraulic end provided by the embodiments of the present disclosure, the pressure-bearing structural member includes a gland and a gland nut, the gland nut is threadedly connected to the valve box, and the fluid discharge channel is located in the gland.

[0011] According to the hydraulic end provided by the embodiments of the present disclosure, the gland includes: a body, the body is cylindrical, the body includes a first end, a second end, and a side surface connecting the first end and the second end; a main flow channel extending along the axis of the body; a plurality of sub-flow channels, each sub-flow channel communicating with the main flow channel; a first opening located at the first end and communicating with the main flow channel; and a plurality of second openings located on the side surface of the body, at least one of the sub-flow channels communicating with at least one of the plurality of second openings.

[0012] According to the hydraulic end provided by the embodiments of the present disclosure, the gland has a low-pressure fluid channel, and the low-pressure fluid channel communicates with the upper liquid hole of the valve box.

[0013] According to the hydraulic end provided by the embodiments of the present disclosure, the inner cavity of the valve box has an inverted T-shaped structure, and the alternating cavity and the low-pressure cavity are arranged along the extending direction of the first axis of the inner cavity.

[0014] According to the hydraulic end provided by the embodiments of the present disclosure, the valve box further includes a high-pressure cavity; the alternating cavity and the high-pressure cavity are arranged along the extending direction of the second axis of the inner cavity, and the first axis intersects with the second axis.

[0015] According to the hydraulic end provided by the embodiments of the present disclosure, the valve box has an upper liquid hole, and the upper liquid hole and the high-pressure cavity are arranged offset in the extending direction of the first axis.

[0016] According to the hydraulic end provided by the embodiments of the present disclosure, the hydraulic end further includes a plunger, a packing set assembly, a packing gland nut, a packing sleeve, and a packing sleeve gland nut. Among them, the inner cavity further includes a plunger cavity configured to place the plunger, the packing sleeve is located between the packing set assembly and the valve box, the packing sleeve gland nut is configured to apply pressure to the packing sleeve, and the packing gland nut is configured to apply pressure to the packing set assembly.

[0017] According to the hydraulic end provided by the embodiments of the present disclosure, the hardness of the packing sleeve is greater than the hardness of the valve box, and the packing sleeve gland nut is welded to the valve box.

[0018] According to the hydraulic end provided by the embodiments of the present disclosure, the packing sleeve gland nut is welded to the valve box.

[0019] An embodiment of the present disclosure further provides a plunger pump, including any one of the above-mentioned hydraulic ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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 and do not limit the present disclosure.

[0021] Figure 1A It is a cross-sectional view of a plunger pump.

[0022] Figure 1B It is Figure 1A a schematic diagram of the hydraulic end in the shown plunger pump.

[0023] Figure 1C It is Figure 1B a schematic diagram of the valve box in the shown hydraulic end.

[0024] Figure 2 It is a cross-sectional view of a gland provided by an embodiment of the present disclosure.

[0025] Figure 3 It is a perspective view of a gland provided by an embodiment of the present disclosure.

[0026] Figure 4 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0027] Figure 5 It is the front view and side view of a spring bracket in a hydraulic end provided by an embodiment of the present disclosure.

[0028] Figure 6 It is a perspective view of another gland provided by an embodiment of the present disclosure.

[0029] Figure 7 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0030] Figure 8 It is a cross-sectional view of a valve box in a hydraulic end provided by an embodiment of the present disclosure.

[0031] Figure 9 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0032] Figure 10 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0033] Figure 11 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0034] Figure 12A is Figure 10 a partial schematic diagram of the fluid discharge passage in the valve box of

[0035] Figure 12B is Figure 10 a partial schematic diagram of the packing sleeve and the packing sleeve gland in the valve box of

[0036] Figure 13 a schematic diagram of each region of the inner cavity in the valve box of a hydraulic end provided by an embodiment of the present disclosure.

[0037] Figure 14 a schematic diagram of the valve box of the hydraulic end provided by an embodiment of the present disclosure.

[0038] Figure 15 a perspective view of the hydraulic end provided by an embodiment of the present disclosure.

[0039] Figure 16 a schematic diagram of another valve box of the hydraulic end provided by an embodiment of the present disclosure.

[0040] Figure 17 a schematic diagram of the intersection of the inner cavities of the valve box in a hydraulic end provided by an embodiment of the present disclosure.

[0041] Figure 18 a schematic diagram of the intersection of the inner cavities of the valve box in another hydraulic end provided by an embodiment of the present disclosure.

[0042] Figure 19 a schematic diagram of a second valve assembly in a hydraulic end provided by an embodiment of the present disclosure.

[0043] Figure 20 a schematic diagram of the valve box on the discharge side of a hydraulic end provided by an embodiment of the present disclosure.

[0044] Figure 21 a schematic diagram of the sealing structure on the discharge side of a hydraulic end provided by an embodiment of the present disclosure.

[0045] Figure 22 a schematic diagram of the valve box on the suction side of a hydraulic end provided by an embodiment of the present disclosure.

[0046] Figure 23 a schematic diagram of the sealing structure on the suction side of a hydraulic end provided by an embodiment of the present disclosure. Detailed implementation manners

[0047] To make the objectives, technical solutions, and advantages of the embodiments of the present disclosure clearer, the technical solutions of the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present disclosure without creative efforts fall within the scope of protection of the present disclosure.

[0048] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure shall have the ordinary meanings understood by those of ordinary skill in the art to which the present disclosure pertains. The "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, terms such as "include" or "comprise" mean that the elements or items appearing before the term cover the elements or items listed after the term and their equivalents, without excluding other elements or items. The terms "connect" or "couple" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", etc. are only used to indicate relative positional relationships, and when the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0049] As one of the key equipment in fracturing operations, the main function of a plunger pump is to convert fracturing fluid at normal pressure and with a certain viscosity into high-pressure and large-flow fracturing fluid for injection into the formation. The performance of the plunger pump directly affects the technical level of fracturing operations in oil and gas fields. Currently, the structure of fracturing pumps at home and abroad generally adopts reciprocating horizontal multi-cylinder plunger pumps, such as three-cylinder and five-cylinder plunger pumps, which usually consist of a fluid end and a power end. The function of the fluid end is to convert mechanical energy into the pressure energy of the working fluid. The function of the power end is to transfer the kinetic energy of the prime mover to the fluid end through a speed reduction transmission system and a crank-link mechanism.

[0050] Figure 1A It is a cross-sectional view of a plunger pump. Figure 1B It is Figure 1A a schematic diagram of the fluid end in the shown plunger pump. Figure 1C It is Figure 1B a schematic diagram of the valve box in the shown fluid end. As Figure 1A shown, the plunger pump 003 includes a power end 002 and a fluid end 001. As Figure 1A and Figure 1B shown, the fluid end 001 mainly includes a valve box 01, a plunger 02, valve assemblies 03, 04, a sealing element, a gland 05, and a gland nut 06. Figure 1A The clamp 07, the tie rod 08, the crosshead 09, the connecting rod 010, the housing 011, and the crankshaft 012 are also shown. AsFigure 1B As shown, the fluid end 001 further includes a valve seat 021, a spring 022, a suction gland 023, a suction gland nut 024, a spring 025, a drain hole 026, a packing gland assembly 027 for sealing, and a packing nut 028. Figure 1C The cross-shaped structure of the valve box 01 is shown.

[0051] As Figure 1A and Figure 1B shown, the working principle of the piston pump is as follows: Driven by the prime mover, the crankshaft 012 of the power end 002 rotates, driving the connecting rod 010 and the crosshead 09 to reciprocate horizontally. The crosshead 09 then drives the piston 02 to reciprocate horizontally in the valve box 01 through the pull rod 08. When the piston 02 moves in the return stroke, the internal volume of the valve box 01 gradually increases, forming a local vacuum. At this time, the valve assembly 03 opens and the valve assembly 04 closes, and the medium enters the inner cavity of the valve box 01. When the piston 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 completed. When the piston 02 moves in the forward stroke, the internal volume of the valve box 01 gradually decreases, the medium is squeezed, and the pressure increases. At this time, the valve assembly 04 opens and the valve assembly 03 closes. Under the action of pressure, the medium enters the drain hole 026. When the piston 02 moves to the limit position in the forward stroke, the medium accommodation space inside the valve box 01 is the smallest, and the liquid discharge action ends. Since the piston 02 continuously reciprocates, the liquid suction and discharge processes alternate, and high-pressure medium is continuously output.

[0052] Referring to Figures 1A to 1C , the valve box of a conventional fluid end is of a cross-shaped structure. As Figure 1C 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 pressure. However, the intersection line is exactly in the alternating chamber 01b. Mechanical analysis shows that the stress concentration at the intersection line is obvious. Coupled with the action of alternating loads, fatigue cracks are likely to occur at the intersection line, resulting in cracking and water leakage of the valve box 01. The valve box is frequently replaced on site, and the replacement cost is high, time-consuming and laborious.

[0053] As the difficulty of fracturing construction increases (manifested as an increase in working pressure), large single-pump displacement has also become an urgent market demand. If the stress concentration effect at the intersection cannot be effectively improved, it will be difficult to improve the service life of the valve box.

[0054] Embodiments of the present disclosure provide a valve box with a T-shaped inner cavity to improve the service life of the valve box, provide a gland to simplify the structure of the fluid end, and improve the performance of the fluid end. Embodiments of the present disclosure also provide a fluid end and a piston pump including the gland and the valve box with a T-shaped inner cavity.

[0055] The gland, fluid end, and piston pump provided by the embodiments of the present disclosure are introduced below.

[0056] Figure 2 A cross-sectional view of a gland provided by an embodiment of the present disclosure. Figure 3 A perspective view of a gland provided by an embodiment of the present disclosure. Figure 4 A cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure. Figure 5 A front view and a side view of a spring bracket in a hydraulic end provided by an embodiment of the present disclosure. Figure 5 (a) is the front view of the spring bracket. Figure 5 (b) is the side view of the spring bracket. Figure 6 Another perspective view of a gland provided by an embodiment of the present disclosure. Figure 7 A cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure. Figure 8 A cross-sectional view of a valve box in a hydraulic end provided by an embodiment of the present disclosure. Figure 9 A cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure.

[0057] As Figure 2 、 Figure 3 、 Figure 6 And Figure 7 As shown, an embodiment of the present disclosure provides a gland 10, and the gland 10 includes: a body 100, a main flow channel 1021, a plurality of sub-flow channels 1022, a first opening P1, and a plurality of second openings P2. As Figure 2 、 Figure 3 、 Figure 6 And Figure 7 As shown, the body 100 is cylindrical, and the body 100 includes a first end E1, a second end E2, and a side surface S0 connecting the first end E1 and the second end E2; the main flow channel 1021 extends along the axis of the body 100; each sub-flow channel 1022 communicates with the main flow channel 1021; the first opening P1 is located at the first end E1 and communicates with the main flow channel 1021; a plurality of second openings P2 are located on the side surface S0 of the body 100, and the sub-flow channel 1022 communicates with at least one of the plurality of second openings P2.

[0058] The gland 10 provided by the embodiment of the present disclosure is conducive to fluid flow, simplifies the structure of the hydraulic end, and a plunger pump including this gland can achieve large displacement output.

[0059] Figures 2 to 4 、 Figure 7 And Figure 9 Show the gland 10a, Figure 6 Show the gland 10b.

[0060] For example, as Figure 2 And Figure 7 As shown, the main flow channel 1021 is located on the axis A0 of the body 100, and the main flow channel 1021 does not penetrate the body 100 on the axis of the body 100. As Figure 2 AndFigure 7 As shown, the left end of the main runner 1021 communicates with the first opening P1, and the right end communicates with the sub-runner 1022. For example, the main runner 1021 extends along the extension direction of the axis A0 of the body 100.

[0061] For example, as Figure 2 and Figure 7 shown, in order to facilitate the flow of fluid, the aperture of the main runner 1021 is larger than that of the sub-runner 1022.

[0062] For example, as Figure 3 and Figure 6 shown, in order to achieve a stable output with a large displacement, a plurality of second openings P2 are evenly distributed in the circumferential direction of the body 100. Since the second opening P2 is located on the side surface S0, the aperture of the sub-runner 1022 and the size of the second opening P2 can be set larger to facilitate the fluid to pass through the gland. The embodiments of the present disclosure are described by taking the gland 10 including four second openings P2 evenly distributed in the circumferential direction of the body 100 as an example.

[0063] For example, as Figure 2 and Figure 7 shown, in order to improve the performance of the gland and extend the service life of the gland, the sub-runner 1022 is inclined relative to the main runner 1021.

[0064] In some embodiments, a plurality of sub-runners 1022 have the same inclination direction and the same inclination degree relative to the main runner 1021. As Figure 2 and Figure 7 shown, a plurality of sub-runners 1022 are all inclined to the right and have the same angle with the main runner 1021.

[0065] For example, as Figure 2 and Figure 7 shown, the range of the acute angle θ1 between the center line L2 of the sub-runner 1022 and the center line L1 of the main runner 1021 is 20 - 80 degrees. As Figure 2 and Figure 7 shown, the gland is described by taking the center line L1 of the main runner 1021 coinciding with the axis A0 of the body 100 as an example.

[0066] For example, as Figure 2 and Figure 7 shown, the distance from the sub-runner 1022 to the axis A0 of the body 100 gradually increases in the direction from the first end E1 to the second end E2. That is, as Figure 2 shown, the sub-runner 1022 is inclined to the right. Of course, in other embodiments, the sub-runner 1022 can also be inclined to the left. In this case, the distance from the sub-runner 1022 to the axis A0 of the body 100 gradually decreases in the direction from the first end E1 to the second end E2.

[0067] For example, asFigure 3 , Figure 6 and Figure 7 As shown in Figure 7 , the gland 10 further includes a bleed channel 1000 and a first bleed port 1001 and a second bleed port 1002 located at both ends of the bleed channel 1000. The first bleed port 1001 is located on the side surface S0 of the main body 100, and the second bleed port 1002 is located on the end surface S2 of the second end E2 of the main body 100.

[0068] For example, as Figures 2 to 4 shown in Figures 2 to 4 , the gland 10a further includes a first sealing position PS1 and a second sealing position PS2. The first sealing position PS1 is configured to set the first sealing ring 1011s, and the second sealing position PS2 is configured to set the second sealing ring 1012s. Both the first sealing position PS1 and the second sealing position PS2 are located on the side surface S0.

[0069] For example, as Figures 2 to 4 shown in Figures 2 to 4 , the first bleed port 1001 is located between the first sealing position PS1 and the second sealing position PS2.

[0070] For example, as Figure 6 shown in Figure 6 , the gland 10b further includes a first sealing groove 1011 and a second sealing groove 1012. The first sealing groove 1011 is configured to accommodate the first sealing ring 1011s, and the second sealing groove 1012 is configured to accommodate the second sealing ring 1012s. Both the first sealing groove 1011 and the second sealing groove 1012 are located on the side surface S0. The first sealing groove 1011 and the first sealing ring 1011s form a first sealing SL1, and the second sealing groove 1012 and the second sealing ring 1012s form a second sealing SL2.

[0071] For example, as Figure 6 shown in Figure 6 , the first bleed port 1001 is located between the first sealing groove 1011 and the second sealing groove 1012.

[0072] For example, the first sealing groove 1011 and the second sealing groove 1012 form a sealing groove 101. The first sealing ring 1011s and the second sealing ring 1012s form a first sealing structure 101s.

[0073] For example, the bleed channel 1000 is configured to circulate fluid when a part of the first sealing structure 101s fails.

[0074] For example, as Figure 3 , Figure 6 and Figure 7 shown in Figure 7 , the bleed channel 1000 is not connected to the main flow channel 1021 and is not connected to the sub - flow channel 1022.

[0075] For example, as Figure 3 , Figure 6 and Figure 7As shown, the first drain port 1001 is located on one side of the end face S1 of the side S0 near the first end E1.

[0076] For example, as Figure 4 , Figures 7 to 9 shown, the hydraulic end further includes a valve box 70. The valve box 70 includes an inner cavity 07. For example, as Figure 8 and Figure 9 shown, the inner cavity 07 of the valve box 70 includes a low-pressure cavity 07a, an alternating cavity 07b, and a high-pressure cavity 07c.

[0077] For example, in the embodiments of the present disclosure, the pressure of the fluid in the high-pressure cavity 07c is greater than the pressure of the fluid in the low-pressure cavity 07a, and the pressure of the fluid in the alternating cavity 07b can vary alternately.

[0078] As Figure 7 and Figure 9 shown, the hydraulic end includes a gland 20, and the gland 20 is threadedly connected to the valve box 70.

[0079] As Figure 7 shown, one end of the drain channel 1000 opens from the end face S2 of the gland (the second drain port 1002), and the other end opens on the outer diameter of the gland (the first drain port 1001). The first drain port 1001 is between two seals (the first seal SL1 and the second seal SL2). When the first seal SL1 fails and liquid leaks, the liquid will fill the annular cavity between the valve box 70 and the gland 10, and then the liquid will flow along the drain channel 1000 to the gap between the gland 10 and the gland nut 20. When a certain amount of liquid accumulates, it will flow out along the outer diameter (threaded part) or the inner hole of the gland nut 20. At this time, if liquid leakage is observed, it indicates that the first seal SL1 has failed. Therefore, the operator can judge the usage condition of the first seal SL1 based on whether there is liquid leakage here, so as not to fail to react in time when the first seal SL1 fails, resulting in the high-pressure liquid piercing into the low-pressure liquid after the second seal SL2 fails, causing pressure crossover and damaging the equipment.

[0080] For example, as Figure 2 and Figure 7 shown, the gland 10 further includes a valve seat groove 1013. The valve seat groove 1013 is located at the first end E1 and communicates with the main flow channel 1021, and the valve seat groove 1013 has a relief groove 1013a on the side facing away from the first end E1 to reduce stress concentration.

[0081] For example, in order to facilitate the disassembly and assembly of the gland during maintenance, the gland 10 further includes a pulling hole 1003. The pulling hole 1003 is located at the second end E2 of the body 100. The pulling hole 1003 is not communicated with the second drain port 1002 and is not communicated with the drain channel 1000. For example, the pulling hole 1003 is located on the axis of the body 100.

[0082] For example, as Figures 2 to 4 , Figures 6 to 7 , and Figure 9 shown, the inside of the gland 10 is provided with a flow channel (main flow channel 1021, sub-flow channel 1022) and a bleed channel 1000, the end face is provided with a draw hole 1003 and a valve seat groove 1013, and a seal groove may be provided on the outer diameter of the gland 10. Low-pressure liquid flows inside the flow channel, which is formed by the intersection of the main flow channel 1021 and the sub-flow channel 1022. The axis of the main flow channel 1021 (center line L1 of the main flow channel 1021) coincides with the axis of the gland 10, and the sub-flow channels 1022 are evenly distributed in the circumferential direction of the gland; the bottom of the valve seat groove 1013 is a plane, the side face is a conical surface, and there is a relief groove 1013a at the root to reduce stress concentration, and the corresponding valve seat is also provided with a conical surface for mating and fixing.

[0083] For example, in some embodiments, as Figure 2 and Figure 3 shown, no seal groove is provided on the left side of the gland of the hydraulic end, and the seal groove is provided on the valve box. The outer diameter of the gland 10 is in interference fit with the seal to prevent the high and low pressure liquids from being pressured together. As Figure 8 and Figure 9 shown, after the gland 10 is worn by the seals (first seal ring 1011s, second seal ring 1012s), the gland can be replaced to reduce the maintenance cost. It should be noted that, as Figure 6 shown, a seal groove 101 may also be provided on the left side of the gland, and it is not limited to the seal groove being provided on the valve box 70. Figure 8 Shows the seal grooves 1018 and 1019 in the valve box 70. As Figure 7 and Figure 8 shown, the first seal ring 1011s is arranged in the seal groove 1018, and the second seal ring 1012s is arranged in the seal groove 1019.

[0084] The gland 10 provided by the embodiments of the present disclosure has at least one of the following beneficial effects.

[0085] (1) Integrating the end plug, flow channel, and base, with multiple functions in one, making the overall structure of the hydraulic end more compact and simple, and the gland in the usual hydraulic end can be used to fix and limit it.

[0086] (2) The gland is used as the base of the valve seat. When the valve seat is worn and needs to be replaced, it can be replaced as a whole with the gland, and there is no need to use other tools to pull it out again, avoiding reducing the maintenance efficiency. After all, the maintenance time is very short during the fracturing construction, and the overall replacement can greatly improve the on-site maintenance efficiency.

[0087] (3) The gland is internally provided with a bleed channel, which can quickly and directly determine whether the seal fails, prevent pressure leakage caused by untimely discovery, resulting in equipment damage and affecting the fracturing construction.

[0088] (4) The hollow structure (flow channel) of the gland enables the smooth flow of low-pressure liquid. The fracturing fluid is generally sand-laden fracturing fluid. The combined use of multiple sub-flow channels and a main flow channel with a large aperture can reduce the risk of sand plugging.

[0089] An embodiment of the present disclosure also provides a fluid end, including any one of the above-mentioned glands 10.

[0090] The inner cavity of the valve box of the fluid end provided by the embodiment of the present disclosure is of a T-shaped structure, and the intersection position is designed in the form of a "flare", which alleviates the problem of stress concentration at the intersection line of the inner cavity. The valve box 70 can be called a T-shaped valve box.

[0091] For example, as Figure 8 and Figure 9 shown, the gland 10 is located in the low-pressure cavity 07a. The inner cavity 07 of the valve box 70 is of an inverted T-shaped structure. The alternating cavity 07b and the low-pressure cavity 07a are arranged along the extension direction of the first axis A1 of the inner cavity 07. The alternating cavity 07b and the high-pressure cavity 07c are arranged along the extension direction of the second axis A2 of the inner cavity 07. The first axis A1 intersects with the second axis A2. The embodiment of the present disclosure is described by taking the first axis A1 perpendicular to the second axis A2 as an example.

[0092] Figure 8 The first axis A1 and the second axis A2 of the inner cavity 07 are shown. As Figure 8 shown, the inner cavity 07 includes a horizontal cavity 0701 and a vertical cavity 0702.

[0093] For example, as Figure 8 and Figure 9 shown, the inner cavity of the valve box 70 is of 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 in the form of a "flare", and the transition is smooth, which can effectively improve the stress concentration effect.

[0094] The structure of the valve box of the fluid end provided by the embodiment of the present disclosure has the following characteristics compared with the valve box of a conventional fluid end.

[0095] 1) The stress concentration effect in the inner cavity is significantly improved.

[0096] For the inner cavity with a cross intersection structure as Figure 1C shown, the intersection includes positions Pa, Pb, Pc, and Pd. The stress concentration points are at positions Pc and Pd. From the mechanical analysis, the stress concentration is very obvious, and fatigue cracks are likely to initiate, resulting in the cracking of the valve box.

[0097] The embodiment of the present disclosure provides a valve box in the hydraulic end where the inner cavities intersect each other without a right angle, and the transition at the intersection of the inner cavities is smooth. The design is optimized at the position most likely to cause stress concentration. The intersection is in a bell-mouth shape without stress concentration points. From a mechanical analysis, the stress concentration effect is significantly improved.

[0098] 2) Simple structure and strong sealing.

[0099] The valve box in the common hydraulic end is a split structure. The packing cavity, suction cavity (low-pressure cavity) and discharge cavity (high-pressure cavity) need to be bolted to the main body of the valve box. This structure is relatively complicated and requires multiple seals for sealing, which invisibly increases multiple leaks. The sealing surface processing precision is high. The more sealing surfaces, the more working hours are required, the lower the processing efficiency, and ultimately it cannot guarantee complete sealing.

[0100] 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.

[0101] 3) Easy maintenance.

[0102] The axis of the plunger in a common hydraulic end is not in line 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 maintenance efficiency. During the actual fracturing construction, Party A will not leave a long time to replace accessories. In some common hydraulic ends, although the axis of the plunger is in line 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 for maintenance.

[0103] 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 a pressure cap is provided on the suction side. The axis of the pressure cap coincides with the axis of the plunger. During maintenance, conventional operations at the well site can be followed.

[0104] For example, the most efficient routine operation for maintaining the plunger or packing pack assembly at the 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, perform normal maintenance, and after maintenance, restore the accessories by performing the above actions in reverse. The entire maintenance process does not require the hydraulic end to be removed from the plunger pump.

[0105] For example,Figure 4 , Figures 7 to 9 As shown in Figures 7 to 9 , the valve box 70 has an upper liquid hole 700, and the upper liquid hole 700 and the high-pressure chamber 07c are arranged offset in the extending direction of the first axis A1.

[0106] For example, as Figure 4 and Figure 9 shown, the hydraulic end further includes a first valve assembly V1, and the first valve assembly V1 is configured to be opened to communicate the low-pressure chamber 07a and the alternating chamber 07b or to be closed to separate the low-pressure chamber 07a and the alternating chamber 07b.

[0107] For example, as Figure 4 and Figure 9 shown, the first valve assembly V1 includes a valve body 1a, a seal 1b (for sealing), a valve seat 1c, a spring 1d, and a spring bracket 1e.

[0108] For example, as Figure 4 and Figure 9 shown, the seal 1b is embedded in the valve body 1a. When the first valve assembly V1 is opened, the valve body 1a embedded with the seal 1b moves to the left, and the low-pressure chamber 07a and the alternating chamber 07b are communicated.

[0109] As Figure 5 shown, the spring bracket 1e is a hollow structure, including a main body e1 and a hollow structure e0, and is limited by the inclined surface S01 with the valve box 70. The spring bracket 1e with the hollow structure e0 is beneficial to the smooth flow of liquid, and is limited by the inclined surface S01 to prevent the spring bracket 1e from shaking in the horizontal chamber of the valve box 70. The horizontal chamber of the corresponding valve box is also provided with an inclined surface to cooperate with the inclined surface of the spring bracket 1e, and the spring bracket 1e contacts the valve box 70 through the inclined surface.

[0110] For example, as Figure 9 shown, the hydraulic end further includes a second valve assembly V2, and the second valve assembly V2 is configured to be opened to communicate the alternating chamber 07b and the high-pressure chamber 07c or to be closed to separate the alternating chamber 07b and the high-pressure chamber 07c.

[0111] For example, as Figure 9 shown, the second valve assembly V2 includes a valve body 2a, a seal 2b (for sealing), a valve seat 2c, a spring 2d, and a base 2f.

[0112] For example, as Figure 9 shown, the seal 2b is embedded in the valve body 2a. When the second valve assembly V2 is opened, the valve body 2a embedded with the seal 2b moves upward, and the high-pressure chamber 07c and the alternating chamber 07b are communicated.

[0113] As Figure 9As shown, the second valve assembly V2 is close to the discharge hole 7005 and opens during the piston's forward movement to allow high-pressure liquid to flow through. The first valve assembly V1 is close to the liquid inlet hole 700 and opens during the piston's return movement to allow low-pressure liquid to flow through. 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 to prevent damage to the valve box 70 during opening and closing (when slapping), thereby extending the service life of the valve box 70.

[0114] For example, as Figure 8 shown, a flared shape is formed by machining at the intersection 7006 of the inner cavity 07 of the valve box 70. For example, the flared shape can be machined by boring, but is not limited to this.

[0115] For example, as Figure 8 and Figure 9 shown, the intersection of the inner cavity 07 includes 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 part (horizontal cavity) of the inner cavity 07 extending along the first axis A1 than the first sub-cavity 071. To reduce 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 A2. The second valve assembly V2 is not placed in the first sub-cavity 071 and the second sub-cavity 072. The second valve assembly V2 is located outside the first sub-cavity 071 and the second sub-cavity 072. The first sub-cavity 071 and the second sub-cavity 072 can be cavities only used for fluid flow. For example, as Figure 8 and Figure 9 shown, the second valve assembly V2 and the second sub-cavity 072 are located on opposite sides of the first sub-cavity 071.

[0116] For example, as Figure 8 and Figure 9 shown, to reduce stress concentration, the dimension D1 of the second sub-cavity 072 in the extension direction of the first axis A1 gradually increases in the direction from a position far from the first axis A1 to a position close to the first axis A1.

[0117] For example, the angle between the part of the valve box 70 for forming the second sub-cavity 072 and the first axis A1 is 30 - 80 degrees. Further for example, the angle between the part of the valve box 70 for forming the second sub-cavity 072 and the first axis A1 is 30 - 60 degrees.

[0118] For example, as Figure 9 shown, the first sub-cavity 071 is a cylindrical cavity, but is not limited to this. For example, as Figure 2 shown, the second sub-cavity 072 is a frustum-shaped cavity, but is not limited to this.

[0119] For example, as Figure 9As shown, the valve box 70 is provided with protective sleeves 73 at positions corresponding to the first sub-chamber 071 and the second sub-chamber 072. There is a protective sleeve 73 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.

[0120] For example, as Figure 9 shown, the gland 10 is of a rotary body structure and is horizontally placed inside the valve box 70. It contacts the first valve assembly V1 on the left side and the gland nut 20 on the right side. The gland nut 20 and the valve box 70 are in threaded fit.

[0121] For example, as Figure 9 shown, the hydraulic end includes a plunger 81. The plunger 81 is a rotary 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. For example, as Figure 9 shown, the hydraulic end further includes a plunger side 70c.

[0122] For example, as Figure 8 shown, the inner cavity 09 further includes a plunger cavity 07d, and the plunger cavity 07d is configured to place the plunger 81. The plunger cavity 07d, the alternating cavity 07b, and the low-pressure cavity 07d are arranged in sequence along the extension direction of the first axis A1 of the inner cavity 07.

[0123] For example, in the embodiments of the present disclosure, the extension direction of the first axis A1 may be the arrangement direction of the alternating cavity 07b and the low-pressure cavity 07a, or the extension direction of the first axis A1 may be the arrangement direction of the plunger cavity 07d, the alternating cavity 07b, and the low-pressure cavity 07a. For example, in the embodiments of the present disclosure, the extension direction of the second axis A2 may be the arrangement direction of the high-pressure cavity 07c and the alternating cavity 07b.

[0124] For example, as Figure 9 shown, the hydraulic end further includes a packing gland assembly 82, and the packing gland assembly 82 includes a packing gland 821, a spacer ring 822, and a gland ring 823.

[0125] For example, as Figure 9 shown, the packing gland 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 ring includes rubber, but is not limited thereto.

[0126] For example, as Figure 9 shown, a lubricating oil passage 7007 is provided on the plunger side of the valve box to lubricate the packing gland 821 (rubber part) and make the reciprocating movement of the plunger 81 smoother; the packing gland 821 wraps around the circumference of the plunger 81, and the packing gland 821 plays a sealing role to prevent liquid leakage during the reciprocating movement of the plunger 81.

[0127] For example, as Figure 9As shown, the inner wall of the packing gland 821 has an interference fit with the plunger 81 to achieve a sealing effect. When the plunger 81 reciprocates, it rubs against the inner wall of the packing gland 821, and forced lubrication is provided here to reduce friction.

[0128] For example, a pulling hole (bolt hole) is provided at the front end of the plunger 81, and a pulling tool is provided. During maintenance, first remove the clamp 86, disconnect it from the power end, and pull out the plunger 81 from the suction side 70a along the first axis A1 of the valve box 70 using the pulling tool.

[0129] For example, as Figure 9 shown, the hydraulic end further includes a packing gland nut 83, and the packing gland nut 83 is configured to apply pressure to the packing gland assembly 82.

[0130] For example, as Figure 9 shown, the packing gland 821 is fixed by tightening the packing gland nut 83, and the packing gland nut 83 is threadedly connected to the valve box 70. The functions of the packing gland nut 83 include: preventing the packing gland 821 from axially moving when the plunger 81 reciprocates, and making the packing gland 821 expand by screwing and squeezing, which is beneficial to sealing. Sealing rings 822 and pressure rings 823 are respectively provided at both ends of the packing gland 821. The sealing ring 822 isolates the packing gland 821 from the valve box 70, and the pressure ring 823 isolates the packing gland 821 from the packing gland nut 83 to protect the packing gland 821 and extend its service life. For example, the sealing ring 822 and the pressure ring 823 can be metal parts.

[0131] For example, as Figure 9 shown, the hydraulic end further includes a packing sleeve 84 and a packing sleeve nut 85. The plunger cavity 07d is configured to place the plunger 81. The packing sleeve 84 is located between the packing gland assembly 82 and the valve box 70, and the packing sleeve nut 85 is configured to apply pressure to the packing sleeve 84.

[0132] For example, as Figure 9 shown, the packing sleeve 84 is axially limited by shoulders and the packing sleeve nut 85.

[0133] For example, as Figure 9 shown, at least one of the packing sleeve 84 and the packing sleeve nut 85 is welded to the valve box 70.

[0134] For example, as Figure 9 shown, the hardness of the packing sleeve 84 is greater than that of the valve box 70. Since the hardness of the packing sleeve 84 is higher than that of the valve box 70, when the valve box 70 is damaged, the packing sleeve 84 will not be damaged. Therefore, the packing sleeve 84 can be fixed to the valve box 85 by welding.

[0135] For example, as Figure 9As shown, the outer diameter of the packing package 821 contacts the packing sleeve 84, and the inner diameter of the packing package 821 contacts the plunger 81; a seal 7008 is provided at the front end of the packing sleeve 84 to prevent high-pressure liquid from entering the gap and causing liquid leakage and damage to the valve box; the packing sleeve 84 is a wear-resistant part and is in interference fit with the valve box 70, and the hardness of the packing sleeve 84 is higher than that of the valve box. The packing sleeve 84 is provided to prevent the packing package 821 from rubbing and damaging the valve box 70 and extend the service life of the valve box.

[0136] For example, as Figure 9 shown, threads are provided on both the inner and outer diameters of the packing sleeve gland 85. The external thread of the packing sleeve gland 85 cooperates with the valve box 70, and the internal thread of the packing sleeve gland 85 cooperates with the packing gland 83. To prevent the packing sleeve gland 85 from loosening when the plunger 81 reciprocates, the packing sleeve gland 85 can be fixed to the valve box 70 by welding.

[0137] Figure 9 The discharge side 70b of the hydraulic end is also shown. The suction side 70a of the valve box 70 is provided with a liquid inlet hole 700, and the discharge side 70b is provided with a discharge hole 7005. For example, the liquid inlet hole 700 is connected to the upper water pipe manifold and low-pressure liquid flows inside; the discharge hole 7005 is connected to the discharge flange and high-pressure liquid flows inside.

[0138] Figure 9 The body 77 of the valve box 70 is also shown. The valve box 70 includes the body 77 and the inner cavity 07.

[0139] For example, as Figure 8 and Figure 9 shown, the valve box 70 is provided with a suction side thread 7001, a discharge side thread 7002, and a plunger side thread 7003. The gland 20 is connected to the valve box 70 through the suction side thread 7001. The gland 50 is connected to the valve box 70 through the discharge side thread 7002. The packing sleeve gland 85 is connected to the valve box 70 through the plunger side thread 7003.

[0140] For example, as Figure 9 shown, both the first valve assembly V1 and the second valve assembly V2 are one-way valves. For example, as Figure 9 shown, the first valve assembly V1 and the second valve assembly V2 can be interchanged. For example, the second valve assembly V2 is placed vertically, 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.

[0141] As Figure 4 and Figure 9As shown, for the first valve assembly V1, the valve seat 1c is arranged in the valve seat groove 1013 of the gland 10. The left side of the gland 10 serves as the base for the valve seat 1c to fix the valve seat 1c. For example, the gland 10 is used in cooperation with the valve body 1a, the seal 1b, the spring 1d and the spring bracket 1e to form a check valve. For example, the axis of the first valve assembly V1 coincides with the axis of the gland 10. When the plunger returns, the valve body 1a opens, and the low-pressure liquid enters the valve chamber 70; when the plunger advances, the valve body 1a closes to prevent the low-pressure liquid from entering the valve chamber 70.

[0142] For example, with reference to Figure 9 , taking the fluid entering the hydraulic end as the fracturing fluid as an example for description, the working principle of the hydraulic end is as follows.

[0143] During liquid suction, the plunger 81 returns (translates 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 secondary flow path 1022, and the main flow path 1021 into the alternating cavity 07b until the alternating cavity 07b is filled with the fracturing fluid. At this time, the liquid in the inner cavity 07 is low-pressure liquid.

[0144] During liquid discharge, the plunger 81 advances (translates to the right), the first valve assembly V1 closes, and the second valve assembly V2 opens. The fracturing fluid flows from the alternating cavity 07b into the high-pressure cavity 07c and is discharged through the discharge hole 7005. At this time, the liquid in the inner cavity 07 is high-pressure liquid.

[0145] The hydraulic end provided by the embodiment of the present disclosure has at least one of the following effects.

[0146] 1) The stress concentration effect in the inner cavity is significantly improved.

[0147] In the inner cavity of the valve chamber of the hydraulic end provided by the embodiment of the present disclosure, there is no right angle 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, and the intersection is in the shape of a flared opening without stress concentration points. From a mechanical analysis, the stress concentration effect is significantly improved.

[0148] 2) The structure is simple and the sealing performance is strong.

[0149] The valve chamber of the hydraulic end provided by the embodiment of the present disclosure is of an integral structure, with tight sealing and high pressure resistance. Fewer seals are used and bolts are not required. The structure is simple and compact, and the risk of valve chamber leakage is low.

[0150] 3) It is convenient for maintenance and repair.

[0151] For 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 chamber. There is a gland on the suction side (the axis of the gland coincides with the axis of the plunger, and the gland is detachable), and during maintenance, the conventional operations at the well site can be carried out.

[0152] Embodiments of the present disclosure further provide a plunger pump, including any one of the above-mentioned hydraulic ends. Since the gland 10 is located on the suction side 70a of the hydraulic end, the gland 10 can also be referred to as the suction gland.

[0153] For example, the gland 10, the hydraulic end containing the gland 10, and the plunger pump can be applied to oil and gas field fracturing / casing equipment.

[0154] Embodiments of the present disclosure provide a hydraulic end having two sets of pressure-bearing components on the suction side and a plunger pump containing the hydraulic end, which is beneficial for maintenance and prolonging the service life of the valve box.

[0155] The following introduces the hydraulic end and the plunger pump provided by the embodiments of the present disclosure.

[0156] Figure 10 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure. Figure 11 It is a cross-sectional view of a hydraulic end provided by an embodiment of the present disclosure. Figure 12A It is Figure 11 A partial schematic view of the flow discharge channel in the valve box of Figure 12B It is Figure 11 A partial schematic view of the packing sleeve and the packing sleeve gland in the valve box of Figure 13 It is a schematic view of each region of the inner cavity in the valve box of a hydraulic end provided by an embodiment of the present disclosure. Figure 14 It is a schematic view of the valve box of the hydraulic end provided by an embodiment of the present disclosure. Figure 15 It is a three-dimensional view of the hydraulic end provided by an embodiment of the present disclosure. Figure 16 It is a schematic view of the valve box of another hydraulic end provided by an embodiment of the present disclosure. Figure 17 It is a schematic view of the intersection of the inner cavities of the valve box in a hydraulic end provided by an embodiment of the present disclosure. Figure 17 (a) is a cross-sectional view of the XY plane of the inner cavity of the valve box. Figure 17 (b) is a schematic view of the YZ plane of the inner cavity of the valve box. Figure 18 It is a schematic view of the intersection of the inner cavities of the valve box in another hydraulic end provided by an embodiment of the present disclosure. Figure 18 (a) is a cross-sectional view of the XY plane of the inner cavity of the valve box. Figure 18 (b) is a schematic view of the YZ plane of the inner cavity of the valve box. Figure 15 The X direction, Y direction, and Z direction are shown. For example, the X direction is the extension direction of the first axis A1 mentioned later, and the Y direction is the extension direction of the second axis A2 mentioned later.

[0157] For example, Figure 8 The valve box shown is Figure 9 The valve box in the hydraulic end shown. For example, Figure 13 The valve box shown is Figure 10The valve box in the hydraulic end shown. For example, Figure 14 The valve box shown is Figure 11 The valve box in the hydraulic end shown.

[0158] Figure 10 and Figure 11 The hydraulic ends shown all include a T-shaped valve box. The inner cavity of the T-shaped valve box is T-shaped. Figure 10 The hydraulic end shown includes a set of pressure-bearing components, while Figure 11 The hydraulic end shown includes two sets of pressure-bearing components.

[0159] Such as Figure 11 shown, an embodiment of the present disclosure provides a hydraulic end, including: a valve box 70, a first valve assembly V1, a first pressure-bearing assembly M1, and a second pressure-bearing assembly M2.

[0160] Such as Figure 10 , Figure 11 , Figure 13 and Figure 14 shown, the valve box 70 includes an inner cavity 07, and the inner cavity 07 includes an alternating cavity 07b and a low-pressure cavity 07a.

[0161] Such as Figure 10 , Figure 11 and Figure 13 shown, the first valve assembly V1 is configured to open to communicate the low-pressure cavity 07a and the alternating cavity 07b or is configured to close to separate the low-pressure cavity 07a and the alternating cavity 07b.

[0162] Such as Figure 11 shown, the first pressure-bearing assembly M1 contacts the first valve assembly V1.

[0163] Such as Figure 11 shown, the second pressure-bearing assembly M2 and the first pressure-bearing assembly M1 are arranged in sequence along the extension direction of the first axis A1 of the inner cavity 07.

[0164] Such as Figure 11 shown, the first valve assembly V1, the first pressure-bearing assembly M1, and the second pressure-bearing assembly M2 are arranged in sequence along the extension direction of the first axis A1 of the inner cavity 07.

[0165] [[ID= and ​ show the suction side 70a, the discharge side 70b, and the plunger side 70c of the hydraulic end.

[0166] For the hydraulic end provided by the embodiment of the present disclosure, two sets of pressure-bearing components are arranged on the suction side 70a, that is, a first pressure-bearing assembly M1 and a second pressure-bearing assembly M2 are arranged. The first valve assembly V1 is connected to the valve box 70 through the first pressure-bearing assembly M1, rather than directly "sitting" on the valve box 70. The first valve assembly V1 does not directly contact the valve box, which is convenient for maintenance and is beneficial to extending the service life of the valve box.

[0167] For example, ​ As shown, the first pressure-bearing component M1 is detachably connected to the valve box 70, and the second pressure-bearing component M2 is detachably connected to the valve box 70, so as to facilitate the removal of the plunger 81 from the suction side 70a.

[0168] For example, ​ 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 by threads.

[0169] 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.

[0170] For example, ​ 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.

[0171] 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 through the alternating pressure cover 13. The alternating pressure cover 13 will move when subjected to force, so it is necessary to use the alternating pressure cap 23 for fixed positioning. For example, the alternating pressure cap 23 is in contact with the alternating pressure cover 13, and the alternating pressure cap 23 and the valve box 70 are fastened by threads, but 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, according to finite element analysis, the stress at the threads of the alternating pressure cap 23 is less than the stress at the threads of the pressure cap of the conventional hydraulic end. The hydraulic end provided in the embodiment of the present disclosure can extend the service life of the valve box 70.

[0172] For example, ​ and ​ As shown, a first sealing structure SE is provided between the alternating pressure cover 13 and the valve box 70 . The valve box 70 has a leakage channel 7000 . The leakage channel 7000 is configured to allow fluid to flow when a part of the first sealing structure SE fails.

[0173] For example, ​ and ​ As shown, the leakage channel 7000 penetrates 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.

[0174] For example, ​ and ​As shown, in order to facilitate manufacturing and make the valve box have high strength, the flow discharge channel 7000 is inclined with respect to the first axis A1 of the inner cavity 07. The acute angle θa formed by the flow discharge 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.

[0175] For example, as ​ shown, the end of the flow discharge channel 7000 far from the inner cavity 07 is closer to the suction side 70a than the end of the flow discharge channel 7000 close to the inner cavity 07. That is, as ​ shown, the end of the flow discharge channel 7000 far from the inner cavity 07 is more to the right than the end of the flow discharge channel 7000 close to the inner cavity 07.

[0176] For example, as ​ and ​ shown, the first sealing structure SE includes a first sealing SE1 and a second sealing SE2. The end of the flow discharge channel 7000 close to the alternating gland 13 is located between the first sealing SE1 and the second sealing SE2. For example, the first sealing SE1 includes a sealing ring, and the second sealing SE2 includes a sealing ring.

[0177] As ​ and ​ shown, the sealing groove of the first sealing structure SE is provided in the alternating gland 13. In other embodiments, the sealing groove of the first sealing structure SE can also be provided in the valve box 70.

[0178] For example, as ​ and ​ shown, the first valve assembly V1 includes a valve body 1a, a seal 1b and a valve seat 1c, and the alternating gland 13 serves as the base of the valve seat 1c.

[0179] For example, as ​ and ​ shown, the first valve assembly V1 further includes a spring 1d and a spring bracket 1e.

[0180] For example, as ​ shown, the spring bracket 1e includes a hollow structure e0 and is limited with the valve box 70 through an inclined surface S01. The spring bracket 1e with the hollow structure e0 is beneficial to smooth liquid flow and is limited through the inclined surface S01 to prevent the spring bracket 1e from shaking in the horizontal cavity of the valve box 70. The horizontal cavity of the corresponding valve box is also provided with an inclined surface to cooperate with the inclined surface of the spring bracket 1e, and the spring bracket 1e contacts the valve box 70 through the inclined surface.

[0181] For example, as ​ shown, the seal 1b is embedded in the valve body 1a. When the first valve assembly V1 is opened, the valve body 1a embedded with the seal 1b moves to the left, and the low-pressure cavity 07a and the alternating cavity 07b are communicated.

[0182] ​ The first valve assembly V1 of the hydraulic end shown includes a base 1f. And ​ The alternating gland 13 in the hydraulic end shown is used as a base for the first valve assembly V1. And, ​ The valve box of the hydraulic end shown is provided with a bleed channel 7000, while ​ No bleed channel is provided in the valve box of the hydraulic end shown.

[0183] For example, as ​ , ​ , ​ , ​ and ​ shown, the valve box 70 has an upper liquid hole 700. As ​ , ​ , ​ , ​ shows a single-sided upper liquid hole. ​ Shows double-sided upper liquid holes 700: upper liquid hole 700a and upper liquid hole 700b. The upper liquid injection method of the valve box 70 can be single-sided upper liquid injection or double-sided upper liquid injection. For example, single-sided upper liquid injection can meet the requirements of small displacement and low sand ratio operations, and will not cause sand plugging; double-sided upper liquid injection can meet the requirements of large displacement and high sand ratio operations, and the double-sided upper liquid holes can ensure stable upper liquid injection and reduce the risk of sand plugging.

[0184] For example, as ​ shown, the alternating gland 13 has a low-pressure fluid channel 130, and the low-pressure fluid channel 130 communicates with the upper liquid hole 700 of the valve box 70. The low-pressure fluid channel 130 can also be called the first channel 130.

[0185] For example, as ​ shown, the alternating pressure cap 23 has a low-pressure fluid channel 230, and the low-pressure fluid channel 230 communicates with the upper liquid hole 700 of the valve box 70. The low-pressure fluid channel 230 can also be called the second channel 230.

[0186] For example, 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, and the suction cap 43 is threadedly connected to the valve box 70.

[0187] For example, as ​ shown, the first pressure-bearing assembly M1 and the second pressure-bearing assembly M2 are provided on opposite sides of the upper liquid hole 700. For example, as ​ shown, the first pressure-bearing assembly M1 and the second pressure-bearing assembly M2 are provided on both sides of the upper liquid hole 700 in the extension direction of the first axis A1. As ​As shown, the first pressure-bearing component M1 is on the left side of the liquid inlet hole 700, and the second pressure-bearing component M2 is on the right side of the liquid inlet hole 700.

[0188] For example, as ​ shown, the alternating pressure cap 13 and the suction pressure cap 33 are respectively arranged on opposite sides of the alternating pressure cap 23. For example, as ​ shown, the alternating pressure cap 23 and the suction pressure cap 33 are respectively arranged on opposite sides of the liquid inlet hole 700. As ​ shown, the alternating pressure cap 23 is arranged on the left side of the liquid inlet hole 700, and the suction pressure cap 33 is arranged on the right side of the liquid inlet hole 700.

[0189] ​ The first valve assembly V1 of the hydraulic end shown includes a base 1f. And ​ the alternating pressure cap 13 in the hydraulic end shown is used as the base of the first valve assembly V1, making the structure of the hydraulic end more compact. ​ The base 1f shown has a low-pressure liquid channel 330, and the low-pressure liquid channel 330 communicates with the liquid inlet hole 700 of the valve box 70.

[0190] For example, as ​ , ​ , ​ and ​ shown, the inner cavity 07 has an inverted T-shaped structure, the alternating cavity 07b and the high-pressure cavity 07c are arranged along the extension direction of the second axis A2 of the inner cavity 07, and the first axis A1 intersects the second axis A2. Thus, the hydraulic end includes an inner cavity 07 with an inverted T-shaped structure, and the valve box 70 can be called a T-shaped valve box. The embodiments of the present disclosure are described by taking the first axis A1 perpendicular to the second axis A2 as an example.

[0191] For example, as ​ shown, the hydraulic end further includes a second valve assembly V2, the inner cavity 07 further includes a high-pressure cavity 07c, and the second valve assembly V2 is configured to be opened to communicate the alternating cavity 07b and the high-pressure cavity 07c or to be closed to separate the alternating cavity 07b and the high-pressure cavity 07c.

[0192] For example, as ​ shown, the second valve assembly V2 includes a valve body 2a, a seal 2b (for sealing), a valve seat 2c, a spring 2d, and a base 2f.

[0193] For example, as ​ shown, the seal 2b is embedded in the valve body 2a. When the second valve assembly V2 is opened, the valve body 2a embedded with the seal 2b moves upward, and the high-pressure cavity 07c and the alternating cavity 07b communicate.

[0194] As ​As shown, the second valve assembly V2 is close to the discharge hole 7005 and opens when the plunger advances to allow high-pressure liquid to flow through; the first valve assembly V1 is close to the liquid inlet hole 700 and opens when the plunger retracts to allow low-pressure liquid to flow through; 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 to prevent damage to the valve box 70 during opening and closing (when slapping) and extend the service life of the valve box 70.

[0195] For example, as ​ shown, 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 A2. The area of the inner cavity 07 between the second valve assembly V2 and the third pressure-bearing assembly M3 is the high-pressure cavity 07c.

[0196] As ​ shown, the third pressure-bearing assembly M3 includes a gland 40 and a gland nut 50. The gland 40 can be called the discharge gland 40, and the gland nut 50 can be called the discharge gland nut 50.

[0197] For example, as ​ shown, the liquid inlet hole 700 and the high-pressure cavity 07c are arranged staggeredly in the extending direction of the first axis A1.

[0198] For example, as ​ and ​ shown, the intersection of the inner cavity 07 includes 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 extending direction of the second axis A2. The second sub-cavity 072 is closer to the part (horizontal cavity) of the inner cavity 07 extending along the first axis A1 than the first sub-cavity 071. To reduce stress concentration, the maximum dimension h2 of the second sub-cavity 072 in the extending direction of the second axis A2 is greater than the maximum dimension h1 of the first sub-cavity 071 in the extending direction of the second axis A2. The second valve assembly V2 is not placed in the first sub-cavity 071 and the second sub-cavity 072. The second valve assembly V2 is located outside the first sub-cavity 071 and the second sub-cavity 072. The first sub-cavity 071 and the second sub-cavity 072 can be cavities only for fluid flow.

[0199] For example, as ​ and ​ shown, to reduce stress concentration, the dimension D1 of the second sub-cavity 072 in the extending direction of the first axis A1 gradually increases from the position far from the first axis A1 to the position close to the first axis A1. That is, the dimension D1 of the second sub-cavity 072 in the extending direction of the first axis A1 gradually increases from top to bottom.

[0200] For example, as ​ and ​As shown, the angle between the part of the valve box 70 for forming the second sub-cavity 072 and the first axis A1 is 30 - 80 degrees. Further, for example, the angle between the part of the valve box 70 for forming the second sub-cavity 072 and the first axis A1 is 30 - 60 degrees.

[0201] For example, as ​ shown, the first sub-cavity 071 is a cylindrical cavity, but is not limited thereto. For example, as ​ shown, the second sub-cavity 072 is a frustum-shaped cavity, but is not limited thereto.

[0202] For example, as ​ 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. There is a protective sleeve 73 at the "flare" 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.

[0203] For example, as ​ shown, the valve box 70 forms a flare shape by machining at the intersection 7006 of the inner cavity 07. For example, the flare shape can be machined by boring, but is not limited thereto.

[0204] For example, as ​ and ​ shown, a protective sleeve 73 is provided at the "flare" of the inner cavity of the valve box 70 to prevent wear of the inner cavity. After the inner cavity is worn, its surface roughness will increase. Coupled with high-pressure operation, fatigue cracks are extremely likely to occur on the surface. Therefore, through the combined (matching) protection method of the "flare" and the protective sleeve 73 at the intersection, the cracking risk can be reduced and the service life of the valve box can be extended. For example, the protective sleeve 73 can be installed inside the valve box by cold fitting, but is not limited to cold fitting. It can also be installed by machining or hot working methods.

[0205] ​ and ​ show the flare 76, the horizontal cavity 0701, and the body 77 of the valve box 70.

[0206] In the embodiment provided by the present disclosure, the inner cavity of the valve box at the hydraulic end is of a T-shaped structure, and the intersection position is designed in the form of a "flare" to relieve the stress concentration problem at the intersection line of the inner cavity.

[0207] For example, as ​ and ​ shown, the alternating gland 13 is located in the low-pressure cavity 07a, the alternating cap 23 is located in the low-pressure cavity 07a, the inner cavity 07 of the valve box 70 has an inverted T-shaped structure, the alternating cavity 07b and the low-pressure cavity 07a are arranged along the extension direction of the first axis A1 of the inner cavity 07, the alternating cavity 07b and the high-pressure cavity 07c are arranged along the extension direction of the second axis A2 of the inner cavity 07, and the first axis A1 intersects with the second axis A2.​ The first axis A1 and the second axis A2 of the inner cavity 07 are shown. As ​ shown, the inner cavity 07 includes a horizontal cavity 0701 and a vertical cavity 0702.

[0208] For example, as ​ and ​ shown, the inner cavity of the valve box 70 is of 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 in the form of a "flare", and the transition is smooth, which can effectively improve the stress concentration effect.

[0209] Compared with the valve box of the usual hydraulic end, the characteristics of the structure of the valve box of the hydraulic end provided by the embodiments of the present disclosure are as described above and will not be elaborated here.

[0210] The hydraulic end provided by the embodiments of the present disclosure does not have the problem of inconvenient maintenance mentioned above. The axis of the plunger coincides with the first axis (horizontal axis) of the valve box. The suction side is provided with a first pressure-bearing assembly M1 and a second pressure-bearing assembly M1. The axes of the first pressure-bearing assembly M1 and the second pressure-bearing assembly M1 both coincide with the axis of the plunger. During maintenance, the conventional operations on the well site can be carried out.

[0211] For example, as ​ shown, the alternating gland 13 is of a rotary body structure, horizontally placed inside the valve box 70, in contact with the first valve assembly V1 on the left side and in contact with the alternating gland nut 23 on the right side. The alternating gland nut 23 is in threaded fit with the valve box 70.

[0212] For example, as ​ and ​ shown, the hydraulic end includes a plunger 81. The plunger 81 is of a rotary body. One end of the plunger 81 is in contact with the liquid inside the valve box 70 for reciprocating motion, and the other end is connected to the power end of the plunger pump through a clamp 86.

[0213] For example, as ​ and ​ shown, the hydraulic end further includes a packing gland assembly 82. The packing gland assembly 82 includes a packing gland 821, a spacer ring 822, and a gland ring 823.

[0214] For example, as ​ and ​ shown, the packing gland 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 ring includes rubber, but is not limited thereto.

[0215] For example, as ​ and ​As shown, a lubricating oil passage 7007 is provided on the plunger side 70c of the valve box 70 for lubricating the packing gland 821 (rubber part), making the reciprocating movement of the plunger 81 smoother; the circumferential direction of the plunger 81 is wrapped by the packing gland 821, and the packing gland 821 plays a sealing role to prevent liquid leakage during the reciprocating movement of the plunger 81.

[0216] For example, as ​ and ​ shown, the inner wall of the packing gland 821 is in interference fit with the plunger 81, playing a sealing role; when the plunger 81 reciprocates, it rubs against the inner wall of the packing gland 821, and forced lubrication here can reduce friction.

[0217] For example, a pulling hole (bolt hole) is provided at the front end of the plunger 81, and a pulling tool is provided. During maintenance, first remove the clamp 86, disconnect the connection with the power end, and pull out the plunger 81 from the suction side 70a along the first axis A1 of the valve box 70 through the pulling tool.

[0218] For example, as ​ and ​ shown, the hydraulic end further includes a packing gland nut 83, and the packing gland nut 83 is configured to apply pressure to the packing gland assembly 82.

[0219] For example, as ​ and ​ shown, the packing gland 821 is fixed by tightening the packing gland nut 83, and the packing gland nut 83 is threadedly connected to the valve box 70. The functions of the packing gland nut 83 include: preventing the packing gland 821 from axially moving during the reciprocating movement of the plunger 81, and making the packing gland 821 expand by screwing and squeezing, which is beneficial to sealing. A spacer ring 822 and a pressure ring 823 are respectively provided at both ends of the packing gland 821. The spacer ring 822 isolates the packing gland 821 from the valve box 70, and the pressure ring 823 isolates the packing gland 821 from the packing gland nut 83, protecting the packing gland 821 and extending the service life of the packing gland 821. For example, the spacer ring 822 and the pressure ring 823 can be metal parts.

[0220] For example, as ​ and ​ shown, the hydraulic end further includes a packing sleeve 84 and a packing sleeve nut 85. The plunger cavity 07d is configured to place the plunger 81. The packing sleeve 84 is located between the packing gland assembly 82 and the valve box 70, and the packing sleeve nut 85 is configured to apply pressure to the packing sleeve 84.

[0221] For example, as ​ and ​ shown, the packing sleeve 84 is axially limited by shoulders and the packing sleeve nut 85.

[0222] For example, as ​ and ​ shown, at least one of the packing sleeve 84 and the packing sleeve nut 85 is welded to the valve box 70.

[0223] For example, as ​ and ​ shown, the hardness of the packing gland 84 is greater than that of the valve box 70. Since the hardness of the packing gland 84 is higher than that of the valve box 70, when the valve box 70 is damaged, the packing gland 84 will not be damaged. Therefore, the packing gland 84 can be fixed to the valve box 85 by welding.

[0224] For example, as ​ and ​ shown, the outer diameter of the packing 821 contacts the packing gland 84, and the inner diameter of the packing 821 contacts the plunger 81; a seal 7008 is provided at the front end of the packing gland 84 to prevent high-pressure liquid from entering the gap and causing liquid leakage and damage to the valve box; the packing gland 84 is a wear-resistant part and is in interference fit with the valve box 70, and the hardness of the packing gland 84 is higher than that of the valve box. The packing gland 84 is provided to prevent the packing 821 from rubbing and damaging the valve box 70 and extend the service life of the valve box.

[0225] For example, as ​ and ​ shown, the inner and outer diameters of the packing gland nut 85 are provided with threads. The external thread of the packing gland nut 85 cooperates with the valve box 70, and the internal thread of the packing gland nut 85 cooperates with the packing nut 83. To prevent the packing gland nut 85 from loosening when the plunger 81 reciprocates, the packing gland nut 85 can be fixed to the valve box 70 by welding.

[0226] ​ , ​ and ​ also shows the discharge side 70b of the fluid end. As ​ and ​ shown, the suction side 70a of the valve box 70 is provided with a liquid inlet hole 700, and the discharge side 70b is provided with a discharge hole 7005. For example, the liquid inlet hole 700 is connected to the upper water pipe manifold and low-pressure liquid flows inside; the discharge hole 7005 can be connected to the discharge flange and high-pressure liquid flows inside.

[0227] For example, as ​ , ​ and ​ shown, the valve box 70 is provided with a suction side thread 7001, a discharge side thread 7002, and a plunger side thread 7003. The suction nut 43 is connected to the valve box 70 through the suction side thread 7001. The nut 50 is connected to the valve box 70 through the discharge side thread 7002. The packing gland nut 85 is connected to the valve box 70 through the plunger side thread 7003.

[0228] For example, as ​ and ​ shown, both the first valve assembly V1 and the second valve assembly V2 are check valves. For example, as ​ and​ As shown, the first valve assembly V1 and the second valve assembly V2 can be interchanged. 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.

[0229] For example, as ​ and ​ shown, the second valve assembly V2 is placed vertically, and the first valve assembly V1 is placed horizontally. The valve seats of both the first valve assembly V1 and the second valve assembly V2 are fixed in cooperation with the valve box through conical surfaces. However, ​ as shown in

[0230] due to the limitation of its aperture, the plunger of the first valve assembly V1 shown cannot be withdrawn from the suction side during maintenance and needs to be withdrawn from the opposite side, making the maintenance more cumbersome. However, this solution has a simple and compact structure, strong interchangeability, and the valve seat and the base directly "sit" in the valve box to bear the alternating load. The load-bearing surfaces are the conical surface and the inclined surface of the valve box, and the load is not transmitted to the threads on the suction side. Therefore, the valve box has a longer service life and stronger stability. The valve body embedded with the seal forms the valve body assembly, and the valve seat and the base form the valve seat assembly. The valve body assembly and the valve seat assembly are matched through the inclined surface, the valve body and the valve seat are in rigid contact, the seal in the valve assembly is not in rigid contact with the base, and the seal in the valve assembly plays a sealing role. ​ As shown in

[0231] for the first valve assembly V1, the valve seat 1c is arranged in the valve seat groove of the alternating gland 13, and the left side of the alternating gland 13 serves as the base of the valve seat 1c for fixing the valve seat 1c. For example, the alternating gland 13 is used in cooperation with the valve body 1a, the seal 1b, the spring 1d, and the spring support 1e to form a one-way valve. For example, the axis of the first valve assembly V1 coincides with the axis of the alternating gland 13. When the plunger returns, the valve body 1a opens, and the low-pressure liquid enters the valve box 70; when the plunger advances, the valve body 1a closes to prevent the low-pressure liquid from entering the valve box 70. ​ For example, referring to

[0232] taking the fluid entering the hydraulic end as the fracturing fluid as an example, the working principle of the hydraulic end is as follows.

[0233] During liquid suction, the plunger 81 returns (moves leftward), 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 passage 230, and the low-pressure fluid passage 130 into the alternating cavity 07b until the alternating cavity 07b is filled with the fracturing fluid. At this time, the liquid in the inner cavity 07 is low-pressure liquid.

[0234] ​ Schematic diagram of a second valve assembly in a hydraulic end provided by an embodiment of the present disclosure. As ​ shown, the valve body 2a includes a boss a1 and a claw a2. The functions of the boss a1 include limiting the spring 2d to prevent the spring 2d from moving radially, and the functions of the boss a1 also include 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 a unified opening height each time.

[0235] As ​ shown, the inner hole of the base 2f is in clearance fit with the claw a2 to guide the claw a2 and prevent the valve body 2a from deflecting under the impact of high-pressure liquid; the valve seat 2c and the base 2f are of a split structure, and the hardness of the base 2f is higher than that of the base 2f. The purpose is to prevent the inclined surface of the valve seat 2c from being worn when the valve body 2a strikes the valve seat 2c, avoid poor sealing caused by wear of the valve seat 2c, and also avoid reducing the service life of the valve seat and the valve body.

[0236] The structure and functions 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 bracket.

[0237] ​ Schematic diagram of a valve box on the discharge side of a hydraulic end provided by an embodiment of the present disclosure. ​ Schematic diagram of a sealing structure on the discharge side of a hydraulic end provided by an embodiment of the present disclosure. ​ Schematic diagram of a valve box on the suction side of a hydraulic end provided by an embodiment of the present disclosure. ​ Schematic diagram of a sealing structure on the suction side of a hydraulic end provided by an embodiment of the present disclosure.

[0238] ​ The seal 1021 is shown. The seal 1021 includes a sealing ring, and a sealing groove is provided at the corresponding position of the base 2f. As ​ and ​ shown, the seal 1021 is provided to achieve the seal between the second valve assembly V2 and the valve box 70.

[0239] ​ The sealing groove 901 is shown, ​ The seal 902 is shown. The seal 902 is provided to achieve the seal of the high-pressure chamber of the inner cavity.

[0240] ​ The sealing groove 903 is shown, ​ The seal 904 is shown. The seal 904 is provided to achieve the seal of the low-pressure chamber of the inner cavity.

[0241] For example, a seal and a groove for setting the seal may be referred to as a sealing structure. For example, the seal 904 and the groove for setting the seal 904 may be referred to as a second sealing structure, and the seal 902 and the groove for setting the seal 902 may be referred to as a third sealing structure. The seal includes a sealing ring.

[0242] For example, in an embodiment of the present disclosure, the fluid end includes: a valve box including an inner cavity, the inner cavity including an alternating cavity and a low-pressure cavity; a first valve assembly located in the inner cavity and configured to open to communicate the low-pressure cavity and the alternating cavity or configured to close to separate the low-pressure cavity and the alternating cavity; a pressure-bearing structural member 99, at least a part of the pressure-bearing structural member 99 is located in the low-pressure cavity, and a first sealing structure located between the pressure-bearing structural member 99 and the valve box; at least one of the valve box and the pressure-bearing structural member 99 has a drain channel configured to flow fluid when a part of the first sealing structure fails. For example, the pressure-bearing structural member 99 is located in the inner cavity.

[0243] For example, the drain channel may be the above-mentioned drain channel 1000 or drain channel 7000.

[0244] For example, in some embodiments, as ​ and ​ shown, the pressure-bearing structural member 99 may include the above-mentioned gland 10. In this case, the drain channel 1000 is provided in the gland 10.

[0245] For example, as ​ and ​ shown, the pressure-bearing structural member 99 includes a gland 10 and a gland nut 20, the gland nut 20 is threadedly connected to the valve box 70, and the drain channel 100 is located in the gland 10.

[0246] For example, in some other embodiments, as ​ shown, the pressure-bearing structural member 99 may include the above-mentioned first pressure-bearing assembly M1. In this case, the drain channel 7000 is provided in the valve box 70.

[0247] For example, the first sealing structure may be the above-mentioned first sealing structure 101s or first sealing structure SE.

[0248] For example, as ​ shown, the first sealing structure 101s includes a first sealing line SL1 and a second sealing line SL2, the drain channel 1000 includes a first drain port 1001 and a second drain port 1002, the first drain port 1001 is closer to the first sealing structure 101s than the second drain port 1002, and the first drain port 1001 is located between the first sealing line SL1 and the second sealing line SL2.

[0249] For example, as ​As shown, the first sealing structure SE includes a first seal SE1 and a second seal SE2. The bleed channel 1000 includes a first bleed port 1001 and a second bleed port 1002. The first bleed port 1001 is closer to the first sealing structure 101s than the second bleed port 1002, and the first bleed port 1001 is located between the first seal SE1 and the second seal SE2.

[0250] For example, as ​ shown, the pressure-bearing structural member 99 includes a first pressure-bearing assembly M1 and a second pressure-bearing assembly M2. The first valve assembly V1, the first pressure-bearing assembly M1, and the second pressure-bearing assembly M2 are arranged in sequence along the extension direction of the first axis A1 of the inner cavity.

[0251] For example, as ​ shown, the first pressure-bearing assembly M1 includes an alternating gland 13 and an alternating gland nut 23. The alternating gland 13 is closer to the first valve assembly V1 than the alternating gland nut 23, and the alternating gland nut 23 is threadedly connected to the valve box 70.

[0252] ​ and ​ The settings of components such as the packing gland assembly 82, packing gland nut 83, packing sleeve 84, and packing sleeve gland nut 85 in the left part of the fluid end shown can be referred to the above description and will not be elaborated here.

[0253] The embodiments of the present disclosure also provide a piston pump, including any one of the above fluid ends.

[0254] For example, the above fluid end and the piston pump can be applied to oil and gas field fracturing / casing equipment.

[0255] The above is only the specific implementation manner of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present disclosure can easily think of changes or substitutions, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. A hydraulic end, comprising: A valve box including an inner cavity, and the inner cavity includes an alternating cavity and a low-pressure cavity; A first valve assembly located in the inner cavity, configured to open to communicate the low-pressure cavity and the alternating cavity or configured to close to separate the low-pressure cavity and the alternating cavity; A pressure-bearing structural member, at least a part of the pressure-bearing structural member is located in the low-pressure cavity; And A first sealing structure located between the pressure-bearing structural member and the valve box; Wherein, the pressure-bearing structural member has a fluid discharge channel, and the fluid discharge channel is configured to circulate fluid when a part of the first sealing structure fails, The pressure-bearing structural member includes a gland, the gland includes a body, the body is cylindrical, the body includes a first end, a second end, and a side surface connecting the first end and the second end; The fluid discharge channel is located in the gland, and the gland further includes a first fluid discharge port and a second fluid discharge port located at both ends of the fluid discharge channel, the first fluid discharge port is located on the side surface of the body, and the second fluid discharge port is located on the end surface of the second end of the body, The first sealing structure includes a first sealing and a second sealing, and the first fluid discharge port is located between the first sealing and the second sealing, The fluid discharge channel is configured to guide the fluid flowing into from the first fluid discharge port to the second fluid discharge port when the first sealing fails.

2. The hydraulic end according to claim 1, wherein The first sealing is closer to the first end of the body than the second sealing, and the first fluid discharge port is closer to the first sealing than the second fluid discharge port.

3. The hydraulic end according to claim 1, wherein, The gland serves as a base for the valve seat in the first valve assembly.

4. The hydraulic end according to claim 1, wherein, The pressure-bearing structural member further includes a gland nut, and the gland nut is threadedly connected to the valve box.

5. The hydraulic end according to any one of claims 1-4, wherein, The gland further includes: A main flow channel extending along the axis of the body; A plurality of sub-flow channels, each sub-flow channel communicates with the main flow channel; A first opening located at the first end and communicating with the main flow channel; and A plurality of second openings located on the side surface of the body, and at least one of the sub-flow channels communicates with at least one of the plurality of second openings.

6. The hydraulic end according to claim 5, wherein, The gland has a low-pressure fluid channel, and the low-pressure fluid channel communicates with the upper liquid hole of the valve box, and the first sealing and the second sealing are located on the same side of the upper liquid hole.

7. The hydraulic end according to any one of claims 1-4, wherein, The inner cavity of the valve box has an inverted T-shaped structure, and the alternating cavity and the low-pressure cavity are arranged along the extending direction of the first axis of the inner cavity.

8. The hydraulic end according to claim 7, wherein, The valve box further includes a high-pressure cavity; the alternating cavity and the high-pressure cavity are arranged along the extending direction of the second axis of the inner cavity, and the first axis intersects with the second axis.

9. The hydraulic end according to claim 8, wherein, The valve box has an upper liquid hole, and the upper liquid hole and the high-pressure cavity are arranged staggeredly in the extending direction of the first axis.

10. The hydraulic end according to any one of claims 1-4 further includes a plunger, a packing assembly, a packing gland, a packing sleeve, and a packing sleeve gland, wherein, The inner cavity further includes a plunger cavity, the plunger cavity is configured to place the plunger, the packing sleeve is located between the packing assembly and the valve box, the packing sleeve gland nut is configured to press the packing sleeve, and the packing gland nut is configured to press the packing assembly.

11. The hydraulic end according to claim 10, wherein, The hardness of the packing sleeve is greater than that of the valve box, and the packing sleeve gland nut is welded to the valve box.

12. The hydraulic end according to claim 10, wherein, The packing sleeve gland nut is welded to the valve box.

13. A plunger pump comprising a hydraulic end according to any one of claims 1 - 12.

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