Gland, fluid end and plunger pump

Abstract

Provided are a gland, a hydraulic end, and a plunger pump. The gland comprises: a body, the body being cylindrical, the body comprising a first end, a second end, and a side connecting the first end and the second end; a main flow channel extending along the axis of the body; a plurality of secondary flow channels, each of which is connected to the main flow channel; a first opening located at the first end and connected to the main flow channel; and a plurality of second openings located at the side of the body, the secondary flow channel being connected to at least one of the plurality of second openings, so as to simplify the structure of the hydraulic end and provide a large displacement output.

Description

Technical Field

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

[0002] At present, fracturing is the main way to increase production in the process of oil and gas field exploitation, and the plunger pump is the main equipment for pumping fracturing media in the production increase operation. In other words, in the entire process of oil and gas exploitation, any process that requires the delivery of media into the well at a specific pressure needs to be achieved by a plunger pump. Summary of the invention

[0003] The embodiments of the present disclosure provide a gland, a hydraulic end and a plunger pump to simplify the structure of the hydraulic end and provide a large displacement output.

[0004] An embodiment of the present disclosure provides a gland, comprising: a body, which is cylindrical and includes a first end, a second end, and a side connecting the first end and the second end; a main flow channel extending along the axis of the body; a plurality of secondary flow channels, each of which is connected to the main flow channel; a first opening located at the first end and connected to the main flow channel; and a plurality of second openings located on the side of the body, the secondary flow channel being connected to at least one of the plurality of second openings.

[0005] According to the gland provided by the embodiment of the present disclosure, the main flow channel is located on the axis of the body, and the main flow channel does not penetrate the body on the axis of the body.

[0006] According to the gland provided by the embodiment of the present disclosure, the aperture of the main flow channel is larger than the aperture of the secondary flow channel.

[0007] According to the gland provided by the embodiment of the present disclosure, the plurality of second openings are evenly distributed in the circumferential direction of the body.

[0008] According to the gland provided by the embodiment of the present disclosure, the secondary flow channel is arranged obliquely relative to the primary flow channel.

[0009] According to the gland provided by the embodiment of the present disclosure, the acute angle between the center line of the secondary flow channel and the center line of the primary flow channel is in the range of 20-80 degrees.

[0010] According to the gland provided by the embodiment of the present disclosure, the distance from the secondary flow channel to the axis of the body gradually increases in the direction from the first end to the second end.

[0011] According to the gland provided in an embodiment of the present disclosure, the gland also includes a leakage channel and a first leakage port and a second leakage port located at both ends of the leakage channel, wherein the first leakage port is located on the side surface of the body, and the second leakage port is located on the end surface of the second end of the body.

[0012] According to the gland provided by the embodiment of the present disclosure, the leakage channel is not connected with the main flow channel, and is not connected with the secondary flow channel.

[0013] According to the gland provided by the embodiment of the present disclosure, the first drain port is located on a side of the side surface close to the end surface of the first end.

[0014] According to the gland provided in an embodiment of the present disclosure, the gland further includes a valve seat groove, the valve seat groove is located at the first end and is connected to the main flow channel, and the valve seat groove has a backing groove on a side away from the first end.

[0015] According to the pressure cover provided in an embodiment of the present disclosure, the pressure cover also includes a first sealing position and a second sealing position, the first sealing position is configured to set a first sealing ring, the second sealing position is configured to set a second sealing ring, the first sealing position and the second sealing position are both located on the side, and the first drain port is located between the first sealing position and the second sealing position.

[0016] According to the pressure cover provided in an embodiment of the present disclosure, the pressure cover also includes a first sealing groove and a second sealing groove, the first sealing groove is configured to accommodate a first sealing ring, the second sealing groove is configured to accommodate a second sealing ring, the first sealing groove and the second sealing groove are both located on the side, and the first drain port is located between the first sealing groove and the second sealing groove.

[0017] According to the gland provided by the embodiment of the present disclosure, the gland further includes a pulling hole, the pulling hole is located at the second end of the body, and the pulling hole is not connected to the second drain port.

[0018] According to the gland provided by the embodiment of the present disclosure, the pulling hole is located on the axis of the body.

[0019] An embodiment of the present disclosure further provides a hydraulic end, comprising any of the above-mentioned glands.

[0020] According to the hydraulic end provided in the embodiment of the present disclosure, the hydraulic end also includes: a valve box, including an inner cavity, the inner cavity includes a low-pressure cavity, an alternating cavity and a high-pressure cavity; the pressure cover is located in the low-pressure cavity, the inner cavity of the valve box is an inverted T-shaped structure, the alternating cavity and the low-pressure cavity are arranged along the extension direction of the first axis of the inner cavity, the alternating cavity and the high-pressure cavity are arranged along the extension direction of the second axis of the inner cavity, and the first axis intersects with the second axis.

[0021] According to the hydraulic end provided by the embodiment of the present disclosure, the valve box has an upper liquid hole, and the upper liquid hole and the high-pressure chamber are staggered in the extension direction of the first axis.

[0022] According to the hydraulic end provided in an embodiment of the present disclosure, the hydraulic end also includes a first valve assembly, the first valve assembly is configured to be opened to connect the low-pressure chamber and the alternating chamber or to be closed to separate the low-pressure chamber and the alternating chamber, the first valve assembly includes a spring bracket, the spring bracket is a hollow structure, and is limited by an inclined surface with the valve box.

[0023] According to the hydraulic end provided in an embodiment of the present disclosure, the intersection of the inner cavity includes a first sub-cavity and a second sub-cavity, the first sub-cavity and the second sub-cavity are arranged along the extension direction of the second axis, the second sub-cavity is closer to the part of the inner cavity extending along the first axis than the first sub-cavity, the maximum dimension of the second sub-cavity in the extension direction of the second axis is larger than the maximum dimension of the first sub-cavity in the extension direction of the second axis, and the dimension of the second sub-cavity in the extension direction of the first axis gradually increases from a position away from the first axis to a position close to the first axis.

[0024] According to the hydraulic end provided by the embodiment of the present disclosure, the valve box is provided with a protective sleeve at a position corresponding to the first sub-cavity and the second sub-cavity.

[0025] According to the hydraulic end provided in an embodiment of the present disclosure, the hydraulic end also includes a second valve assembly, the second valve assembly is configured to be opened to connect the alternating chamber and the high-pressure chamber or to be closed to separate the alternating chamber and the high-pressure chamber, and the second valve assembly and the second sub-chamber are located on opposite sides of the first sub-chamber.

[0026] An embodiment of the present disclosure also provides a plunger pump, comprising any of the above-mentioned hydraulic ends. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] 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, but are not intended to limit the present disclosure.

[0028] Figure 1A A cross-sectional view of a plunger pump.

[0029] Figure 1B for Figure 1A Schematic diagram of the hydraulic end of the plunger pump shown.

[0030] Figure 1C for Figure 1B Schematic diagram of the valve box in the hydraulic end shown.

[0031] Figure 2 A cross-sectional view of a gland provided in accordance with an embodiment of the present disclosure.

[0032] Figure 3 A stereoscopic view of a gland provided in accordance with an embodiment of the present disclosure.

[0033] Figure 4 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure.

[0034] Figure 5 A front view and a side view of a spring support in a fluid end provided in an embodiment of the present disclosure.

[0035] Figure 6 A three-dimensional view of another gland provided in accordance with an embodiment of the present disclosure.

[0036] Figure 7 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure.

[0037] Figure 8 A cross-sectional view of a valve box in a fluid end provided for an embodiment of the present disclosure.

[0038] Fig. 9 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure.

[0039] Fig.10 A schematic diagram of the intersection of the inner cavities of a valve box in a hydraulic end provided in an embodiment of the present disclosure.

[0040] Fig.11 A schematic diagram of the intersection of the inner cavities of another valve box in a hydraulic end provided in an embodiment of the present disclosure.

[0041] Fig.12 A schematic diagram of a second valve assembly in a fluid end provided for an embodiment of the present disclosure.

[0042] Fig.13 A schematic diagram of a valve box on the discharge side of a hydraulic end provided in accordance with an embodiment of the present disclosure.

[0043] Fig.14 A schematic diagram of a sealing structure on the discharge side of a hydraulic end provided in an embodiment of the present disclosure.

[0044] Fig.15 A schematic diagram of a valve box on the suction side of a hydraulic end provided in accordance with an embodiment of the present disclosure.

[0045] Fig.16 A schematic diagram of a sealing structure on the suction side of a hydraulic end provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0046] In order to make the purpose, technical solution and advantages of the embodiments of the present disclosure clearer, the technical solution of the embodiments of the present disclosure will be clearly and completely described below in conjunction with the drawings of the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, not all of the embodiments. Based on the described embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0047] Unless otherwise defined, the technical terms or scientific terms used in the present disclosure should be understood by people with ordinary skills in the field to which the present disclosure belongs. The "first", "second" and similar words used in the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, "include" or "comprise" and similar words mean that the elements or objects appearing before the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0048] As one of the key equipment in fracturing construction, the main function of the plunger pump is to convert the fracturing fluid with a certain viscosity under normal pressure into a high-pressure, 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. At present, the structure of fracturing pumps at home and abroad generally adopts a reciprocating horizontal multi-cylinder plunger pump, such as a three-cylinder plunger pump and a five-cylinder plunger pump, which is usually composed of a hydraulic end and a power end. The function of the hydraulic 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 hydraulic end through the reduction transmission system and the crank-connecting rod mechanism.

[0049] Figure 1A A cross-sectional view of a plunger pump. Figure 1B for Figure 1A Schematic diagram of the hydraulic end of the plunger pump shown. Figure 1C for Figure 1B Schematic diagram of the valve box in the hydraulic end shown in FIG. Figure 1A As shown, the plunger pump 003 includes a power end 002 and a fluid end 001. Figure 1A and Figure 1B As shown, the hydraulic end 001 mainly includes a valve box 01, a plunger 02, a valve assembly 03, a valve assembly 04, a sealing element, a gland 05 and a gland 06. Figure 1A Also shown are a clamp 07, a pull rod 08, a cross head 09, a connecting rod 010, a housing 011, and a crankshaft 012. Figure 1B As shown, the hydraulic end 001 also includes a valve seat 021, a spring 022, a suction gland 023, a suction cap 024, a spring 025, a drain hole 026, a sealing packing package assembly 027, and a packing cap 028. Figure 1C The cross-intersecting structure of the valve box 01 is shown.

[0050] like Figure 1A and Figure 1B As shown, the working principle of the plunger pump is as follows: the crankshaft 012 of the power end 002 rotates under the drive of the prime mover, driving the connecting rod 010 and the crosshead 09 to reciprocate horizontally, and the crosshead 09 then drives the plunger 02 to reciprocate horizontally in the valve box 01 through the pull rod 08. When the plunger 02 makes a return motion, the internal volume of the valve box 01 gradually increases, forming a partial vacuum. At this time, the valve assembly 03 opens, the valve assembly 04 closes, and the medium enters the inner cavity of the valve box 01. When the plunger 02 returns to the limit position, the inner cavity of the valve box 01 is filled with the medium, and the liquid suction action is completed. When the plunger 02 makes a forward motion, 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, the valve assembly 03 closes, and the medium enters the drainage hole 026 under the action of pressure. When the plunger 02 advances to the limit position, the medium accommodating space inside the valve box 01 is the smallest, and the drainage action is completed. As the plunger 02 continuously reciprocates, the liquid suction and liquid discharge processes are performed alternately, and the high-pressure medium is continuously output.

[0051] refer to Figures 1A to 1C The valve box of the hydraulic end is usually a cross-intersecting structure, such as Figure 1C As shown, the inner cavity of the valve box 02 is divided into a low-pressure cavity 01a, an alternating cavity 01b and a high-pressure cavity 01c according to the pressure. However, the intersection line is just in the alternating cavity 01b. Mechanical analysis shows that the stress concentration at the intersection line is obvious. Coupled with the effect of the alternating load, fatigue cracks are easily generated at the intersection line, resulting in cracking and leakage of the valve box 01. The valve box needs to be replaced frequently on site, and the replacement cost is high, which is time-consuming and labor-intensive.

[0052] As fracturing construction becomes more and more difficult (as reflected by higher working pressure), large displacement of a single machine has become an urgent market demand. If the stress concentration effect at the intersection is not effectively improved, the life of the valve box will be difficult to increase.

[0053] The embodiment of the present disclosure provides a valve box with a T-shaped inner cavity to improve the service life of the valve box, and provides a gland to simplify the structure of the hydraulic end and improve the performance of the hydraulic end. The embodiment of the present disclosure also provides a hydraulic end and a plunger pump containing the gland and the valve box with a T-shaped inner cavity.

[0054] The gland, hydraulic end and plunger pump provided in the embodiments of the present disclosure are introduced below.

[0055] Figure 2 A cross-sectional view of a gland provided in accordance with an embodiment of the present disclosure. Figure 3 A stereoscopic view of a gland provided in accordance with an embodiment of the present disclosure. Figure 4 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure. Figure 5 A front view and a side view of a spring support in a fluid end provided in an embodiment of the present disclosure. Figure 5 (a) is the front view of the spring bracket. Figure 5 (b) is a side view of the spring bracket. Figure 6 A three-dimensional view of another gland provided in accordance with an embodiment of the present disclosure. Figure 7 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure. Figure 8 A cross-sectional view of a valve box in a fluid end provided for an embodiment of the present disclosure. Fig. 9 A cross-sectional view of a fluid end provided for an embodiment of the present disclosure.

[0056] like Figure 2 , Figure 3 , Figure 6 as well as Figure 7 As shown, an embodiment of the present disclosure provides a gland 10, which includes: a body 100, a main flow channel 1021, a plurality of secondary flow channels 1022, a first opening P1, and a plurality of second openings P2. Figure 2 , Figure 3 , Figure 6 as well as Figure 7 As shown, the main body 100 is cylindrical, and the main body 100 includes a first end E1, a second end E2, and a side S0 connecting the first end E1 and the second end E2; the main channel 1021 extends along the axis of the main body 100; each secondary channel 1022 is connected to the main channel 1021; the first opening P1 is located at the first end E1 and is connected to the main channel 1021; multiple second openings P2 are located on the side S0 of the main body 100, and the secondary channel 1022 is connected to at least one of the multiple second openings P2.

[0057] The gland 10 provided in the embodiment of the present disclosure facilitates fluid circulation, simplifies the structure of the hydraulic end, and the plunger pump containing the gland can achieve large displacement output.

[0058] Figures 2 to 4 , Figure 7 and Fig. 9 The gland 10a is shown, Figure 6 A gland 10b is shown.

[0059] For example, Figure 2 and Figure 7 As shown, the main flow channel 1021 is located on the axis A0 of the main body 100, and the main flow channel 1021 does not penetrate the main body 100 on the axis of the main body 100. Figure 2 and Figure 7 As shown, the left end of the main flow channel 1021 is communicated with the first opening P1, and the right end is communicated with the secondary flow channel 1022. For example, the main flow channel 1021 extends along the extension direction of the axis A0 of the body 100.

[0060] For example, Figure 2 and Figure 7 As shown, in order to facilitate the circulation of fluid, the aperture of the main flow channel 1021 is larger than the aperture of the secondary flow channel 1022 .

[0061] For example, Figure 3 and Figure 6 As shown, in order to achieve a large displacement and stable output, a plurality of second openings P2 are evenly distributed in the circumferential direction of the body 100. Because the second openings P2 are located on the side S0, the aperture of the secondary flow channel 1022 and the size of the second openings P2 can be set larger to facilitate the passage of the fluid through the gland. The embodiment of the present disclosure is described by taking the gland 10 including four second openings P2 evenly distributed in the circumferential direction of the body 100 as an example.

[0062] For example, Figure 2 and Figure 7 As shown, in order to improve the performance of the gland and extend the service life of the gland, the secondary flow channel 1022 is inclined relative to the primary flow channel 1021 .

[0063] In some embodiments, the plurality of secondary flow channels 1022 have the same inclination direction and the same inclination degree relative to the primary flow channel 1021. Figure 2 and Figure 7 As shown, the plurality of secondary flow channels 1022 are all inclined to the right and have the same angle with the primary flow channel 1021 .

[0064] For example, Figure 2 and Figure 7 As shown, the acute angle θ1 between the center line L2 of the secondary flow channel 1022 and the center line L1 of the primary flow channel 1021 is in the range of 20-80 degrees. Figure 2 and Figure 7 The gland shown is described by taking the example that the center line L1 of the main channel 1021 coincides with the axis A0 of the body 100 .

[0065] For example, Figure 2 and Figure 7 As shown in FIG. 1 , the distance from the secondary flow channel 1022 to the axis A0 of the body 100 gradually increases from the first end E1 to the second end E2. Figure 2 As shown, the secondary flow channel 1022 is inclined to the right. Of course, in other embodiments, the secondary flow channel 1022 may also be inclined to the left. In this case, the distance between the secondary flow channel 1022 and the axis A0 of the body 100 gradually decreases from the first end E1 to the second end E2.

[0066] For example, Figure 3 , Figure 6 and Figure 7 As shown, the gland 10 further includes a leakage channel 1000 and a first leakage port 1001 and a second leakage port 1002 located at both ends of the leakage channel 1000 . The first leakage port 1001 is located on the side surface S0 of the body 100 , and the second leakage port 1002 is located on the end surface S2 of the second end E2 of the body 100 .

[0067] For example, Figures 2 to 4 As shown, 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 a first sealing ring 1011s, and the second sealing position PS2 is configured to set a second sealing ring 1012s. The first sealing position PS1 and the second sealing position PS2 are both located on the side S0.

[0068] For example, Figures 2 to 4 As shown, the first drain port 1001 is located between the first sealing position PS1 and the second sealing position PS2.

[0069] For example, Figure 6 As shown, 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 a first sealing ring 1011s, and the second sealing groove 1012 is configured to accommodate a second sealing ring 1012s. The first sealing groove 1011 and the second sealing groove 1012 are both located on the side S0. The first sealing groove 1011 and the first sealing ring 1011s constitute a first seal SL1, and the second sealing groove 1012 and the second sealing ring 1012s constitute a second seal SL2.

[0070] For example, Figure 6 As shown, the first drain port 1001 is located between the first sealing groove 1011 and the second sealing groove 1012 .

[0071] For example, the first sealing groove 1011 and the second sealing groove 1012 constitute the sealing groove 101. The first sealing ring 1011s and the second sealing ring 1012s constitute the first sealing structure 101s.

[0072] For example, the leakage channel 1000 is configured to communicate fluid when the first sealing structure 101s at least partially fails.

[0073] For example, Figure 3 , Figure 6 and Figure 7 As shown, the leakage channel 1000 is not connected to the main flow channel 1021 , and is not connected to the secondary flow channel 1022 .

[0074] For example, Figure 3 , Figure 6 and Figure 7As shown, the first drain port 1001 is located on a side of the end surface S1 of the side surface S0 close to the first end E1.

[0075] For example, Figure 4 , Figures 7 to 9 As shown, the hydraulic end further includes a valve box 70. The valve box 70 includes an inner cavity 07. For example, Figure 8 and Fig. 9 As shown, the inner chamber 07 of the valve box 70 includes a low-pressure chamber 07a, an alternating chamber 07b and a high-pressure chamber 07c.

[0076] For example, in the embodiment of the present disclosure, the pressure of the fluid in the high-pressure chamber 07c is greater than the pressure of the fluid in the low-pressure chamber 07a, and the pressure of the fluid in the alternating chamber 07b may change alternately.

[0077] like Figure 7 and Fig. 9 As shown, the hydraulic end includes a pressure cap 20, and the pressure cap 20 is connected to the valve box 70 by threads.

[0078] like Figure 7 As shown, one end of the leakage channel 1000 is opened from the end surface S2 of the gland (the second leakage port 1002), and the other end is opened on the outer diameter of the gland (the first leakage port 1001). The first leakage port 1001 is between two seals (the first seal SL1 and the second seal SL2). When the first seal SL1 fails, liquid leakage occurs, and the liquid will fill the annular cavity between the valve box 70 and the gland 10, and then the liquid will flow along the leakage channel 1000 to the gap between the gland 10 and the cap 20. When a certain amount of liquid accumulates, it will flow out along the outer diameter (thread) or inner hole of the cap 20. At this time, liquid leakage is observed, indicating that the first seal SL1 has failed. Therefore, the operator will judge the use of the first seal SL1 based on whether there is liquid leakage here, so as not to fail to respond 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 cross pressure and damage to the equipment.

[0079] For example, Figure 2 and Figure 7 As shown, the gland 10 further includes a valve seat groove 1013 , which is located at the first end E1 and communicates with the main flow channel 1021 , and has a backing groove 1013 a on a side away from the first end E1 for reducing stress concentration.

[0080] For example, in order to facilitate the disassembly and assembly of the gland during maintenance, the gland 10 further includes a pulling hole 1003, which is located at the second end E2 of the body 100, and is not connected to the second drain port 1002, and is not connected to the drain channel 1000. For example, the pulling hole 1003 is located on the axis of the body 100.

[0081] For example, Figures 2 to 4 , Figure 6 to Figure 7 ,as well as Fig. 9 As shown, the gland 10 is provided with flow channels (main flow channel 1021, secondary flow channel 1022) and leakage channel 1000 inside, and the end surface is provided with a drawing hole 1003 and a valve seat groove 1013, and the outer diameter of the gland 10 may be provided with a sealing groove. Low-pressure liquid flows inside the flow channel, which is formed by the intersection of the main flow channel 1021 and the secondary flow channel 1022. The axis of the main flow channel 1021 (the center line L1 of the main flow channel 1021) coincides with the axis of the gland 10, and the secondary flow channel 1022 is evenly distributed in the circumferential direction of the gland; the bottom of the valve seat groove 1013 is a plane, the side is a conical surface, and the root is provided with a backing groove 1013a for reducing stress concentration, and the corresponding valve seat is also provided with a conical surface to match and fix it.

[0082] For example, in some embodiments, Figure 2 and Figure 3 As shown, the left side of the gland of the hydraulic end is not provided with a sealing groove, and the sealing groove is provided on the valve box. The outer diameter of the gland 10 is interference fit with the seal to prevent high and low pressure liquids from being pressurized. Figure 8 and Fig. 9 As shown, after the gland 10 is worn by the seal (the first sealing ring 1011s, the second sealing ring 1012s), the gland can be replaced to reduce maintenance costs. Figure 6 As shown, a sealing groove 101 may also be provided on the left side of the gland, and the sealing groove is not limited to being provided on the valve box 70 . Figure 8 The sealing groove 1018 and the sealing groove 1019 in the valve box 70 are shown. Figure 7 and Figure 8 As shown, a first sealing ring 1011s is disposed in the sealing groove 1018 , and a second sealing ring 1012s is disposed in the sealing groove 1019 .

[0083] The gland 10 provided by the embodiment of the present disclosure includes at least one of the following beneficial effects.

[0084] (1) The end plug, flow channel and base are integrated into one, and the multi-functions are integrated into one, making the overall structure of the hydraulic end more compact and simple, and the hydraulic end can be fixed and limited by using the pressure cap in the common hydraulic end.

[0085] (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 together with the gland. There is no need to use other tools to pull it out, which avoids reducing the maintenance efficiency. After all, the maintenance time during fracturing construction is very short. The overall replacement can greatly improve the on-site maintenance efficiency.

[0086] (3) The built-in leakage channel of the gland can quickly and directly determine whether the seal has failed, preventing cross-pressure caused by untimely discovery, causing damage to equipment and affecting fracturing construction.

[0087] (4) The hollow structure (flow channel) of the gland allows low-pressure liquid to flow smoothly. Fracturing fluid is generally sand-entrained fracturing fluid. The use of multiple secondary flow channels and large-diameter main flow channels can reduce the risk of sand blockage.

[0088] An embodiment of the present disclosure further provides a hydraulic end, comprising any of the above-mentioned glands 10 .

[0089] The inner cavity of the valve box of the hydraulic end provided in the embodiment of the present disclosure is a T-shaped structure, and the intersection position is designed to be a "bell mouth" form to reduce 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.

[0090] For example, Figure 8 and Fig. 9 As shown, the gland 10 is located in the low-pressure chamber 07a, the inner chamber 07 of the valve box 70 is an inverted T-shaped structure, the alternating chamber 07b and the low-pressure chamber 07a are arranged along the extension direction of the first axis A1 of the inner chamber 07, and the alternating chamber 07b and the high-pressure chamber 07c are arranged along the extension direction of the second axis A2 of the inner chamber 07, and the first axis A1 intersects the second axis A2. The embodiment of the present disclosure is described by taking the first axis A1 and the second axis A2 as perpendicular as an example.

[0091] Figure 8 The first axis A1 and the second axis A2 of the inner cavity 07 are shown. Figure 8 As shown, the inner cavity 07 includes a horizontal cavity 0701 and a vertical cavity 0702 .

[0092] For example, Figure 8 and Fig. 9 As shown, the inner cavity of the valve box 70 is a T-shaped structure. According to the installation positions of the first valve assembly and the second valve assembly, the inner cavity 07 is divided into a low-pressure cavity 07a, an alternating cavity 07b and a high-pressure cavity 07c. The intersection of the inner cavity 07 is designed as a "bell-mouth" form with a smooth transition, which can effectively improve the stress concentration effect.

[0093] Compared with a conventional valve box of a hydraulic end, the structure of the valve box of the hydraulic end provided in the embodiments of the present disclosure has the following characteristics.

[0094] 1) The stress concentration effect in the inner cavity is significantly improved.

[0095] The inner cavity of the cross-intersecting structure is Figure 1C As shown, the intersections include 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 easily generated, resulting in cracking of the valve box.

[0096] 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.

[0097] 2) Simple structure and strong sealing.

[0098] 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.

[0099] 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.

[0100] 3) Easy maintenance.

[0101] 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.

[0102] 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.

[0103] 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.

[0104] For example, Figure 4 , Figures 7 to 9 As shown, the valve box 70 has an upper liquid hole 700, and the upper liquid hole 700 and the high-pressure chamber 07c are staggered in the extension direction of the first axis A1.

[0105] For example, Figure 4 and Fig. 9 As shown, the hydraulic end further includes a first valve assembly V1, which is configured to be opened to connect 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.

[0106] For example, Figure 4 and Fig. 9 As shown, the first valve assembly V1 includes a valve body 1a, a sealing member 1b (playing a sealing role), a valve seat 1c, a spring 1d and a spring support 1e.

[0107] For example, Figure 4 and Fig. 9 As shown, the sealing member 1b is embedded in the valve body 1a. When the first valve assembly V1 is opened, the valve body 1a embedded with the sealing member 1b moves to the left, and the low-pressure chamber 07a and the alternating chamber 07b are connected.

[0108] like Figure 5 As shown, the spring bracket 1e is a hollow structure, including a main body e1 and a hollow structure e0, and is limited by an inclined surface S01 with the valve box 70. The spring bracket 1e with the hollow structure e0 is conducive to smooth liquid flow, and is limited by 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 that cooperates with the inclined surface of the spring bracket 1e, and the spring bracket 1e contacts the valve box 70 through the inclined surface.

[0109] For example, Fig. 9 As shown, the hydraulic end further includes a second valve assembly V2, which is configured to be opened to connect 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.

[0110] For example, Fig. 9 As shown, the second valve assembly V2 includes a valve body 2a, a sealing member 2b (playing a sealing role), a valve seat 2c, a spring 2d and a base 2f.

[0111] For example, Fig. 9 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 chamber 07c and the alternating chamber 07b are connected.

[0112] like Fig. 9As shown, the second valve component V2 is close to the discharge hole 7005, opens when the plunger moves forward, and circulates high-pressure liquid; the first valve component V1 is close to the upper liquid hole 700, opens when the plunger returns, and circulates low-pressure liquid; the base 2f of the second valve component V2 is directly embedded in the valve box 70, and its hardness is greater than that of the valve box 70, which prevents damage to the valve box 70 during opening and closing (when tapping), thereby extending the service life of the valve box 70.

[0113] For example, Figure 8 As shown, the valve box 70 is processed into a bell-mouth shape at the intersection 7006 of the inner cavity 07. For example, the bell-mouth shape can be processed by boring, but is not limited to this.

[0114] For example, Figure 8 and Fig. 9 As 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, in order 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 used only for circulating fluid.

[0115] For example, Figure 8 and Fig. 9 As shown, the second valve assembly V2 and the second sub-chamber 072 are located on opposite sides of the first sub-chamber 071 .

[0116] For example, Figure 8 and Fig. 9 As shown, in order to alleviate stress concentration, the dimension D1 of the second subcavity 072 in the extension direction of the first axis A1 gradually increases 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 portion of the valve box 70 used to form the second sub-cavity 072 and the first axis A1 is 30-80 degrees. For further example, the angle between the portion of the valve box 70 used to form the second sub-cavity 072 and the first axis A1 is 30-60 degrees.

[0118] For example, Fig. 9 As shown, the first sub-cavity 071 is a cylindrical cavity, but is not limited thereto. Figure 2 As shown, the second sub-cavity 072 is a truncated cone-shaped cavity, but is not limited thereto.

[0119] For example, Fig. 9 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. The protective sleeve 73 is provided at the "bell mouth" of the inner cavity 07 of the valve box 70 to protect the inner cavity 07 and extend the service life of the valve box 70.

[0120] For example, Fig. 9 As shown, the pressure cover 10 is a rotating body structure, which is horizontally placed inside the valve box 70, contacts the first valve assembly V1 on the left side, and contacts the pressure cap 20 on the right side. The pressure cap 20 and the valve box 70 are matched by threads.

[0121] For example, Fig. 9 As shown, the hydraulic end includes a plunger 81. The plunger 81 is a rotating body, one end of the plunger 81 contacts the liquid inside the valve box 70 and reciprocates, and the other end is connected to the power end of the plunger pump through a clamp 86. For example, Fig. 9 As shown, the fluid end also includes a plunger side 70c.

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

[0123] For example, Fig. 9 As shown, the hydraulic end further includes a packing pack assembly 82 , and the packing pack assembly 82 includes a packing pack 821 , a spacer ring 822 , and a pressure ring 823 .

[0124] For example, Fig. 9 As shown, the packing package 821 includes three packing rings. Of course, the number of packing rings is not limited to that shown in the figure, and can be determined according to needs. For example, the material of the packing rings includes rubber, but is not limited thereto.

[0125] For example, Fig. 9 As shown, a lubricating oil passage 7007 is provided on the plunger side of the valve box for lubricating the packing pack 821 (rubber part) to make the reciprocating motion of the plunger 81 smoother; the plunger 81 is wrapped with the packing pack 821 in the circumference, and the packing pack 821 acts as a seal to prevent liquid leakage when the plunger 81 reciprocates.

[0126] For example, Fig. 9 As shown, the inner wall of the packing pack 821 is interference fit with the plunger 81 to play a sealing role; when the plunger 81 reciprocates, it rubs against the inner wall of the packing pack 821, and forced lubrication here can reduce friction.

[0127] For example, a pulling hole (bolt hole) is provided at the front end of the plunger 81 and is equipped with a pulling tool. During maintenance, the clamp 86 is first removed and disconnected from the power end, and the plunger 81 is pulled out from the suction side 70a along the first axis A1 of the valve box 70 by the pulling tool.

[0128] For example, Fig. 9 As shown, the hydraulic end further includes a packing press cap 83 , and the packing press cap 83 is configured to apply pressure to the packing package assembly 82 .

[0129] For example, the packing pack 821 is fixed by the packing pressure cap 83, and the packing pressure cap 83 is connected to the valve box 70 by threads. The packing pressure cap 83 has the following functions: preventing the packing pack 821 from axial movement when the plunger 81 reciprocates, and expanding the packing pack 821 by tightening and squeezing, which is beneficial to sealing. The packing pack 821 is provided with a spacer ring 822 and a pressure ring 823 at both ends, respectively. The spacer ring 822 isolates the packing pack 821 from the valve box 70, and the pressure ring 823 isolates the packing pack 821 from the packing pressure cap 83, thereby protecting the packing pack 821 and extending the service life of the packing pack 821. For example, the spacer ring 822 and the pressure ring 823 can be metal parts.

[0130] For example, Fig. 9 As shown, the hydraulic end further includes a packing sleeve 84 and a packing sleeve pressure cap 85 , the plunger cavity 07 d is configured to place the plunger 81 , the packing sleeve 84 is located between the packing package assembly 82 and the valve box 70 , and the packing sleeve pressure cap 85 is configured to apply pressure to the packing sleeve 84 .

[0131] For example, Fig. 9 As shown, the packing sleeve 84 is axially limited by the shoulder and the packing sleeve pressing cap 85.

[0132] For example, at least one of the packing sleeve 84 and the packing sleeve pressure cap 85 is welded to the valve box 70 .

[0133] For example, 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, so the packing sleeve 84 and the valve box 85 can be fixed by welding.

[0134] For example, Fig. 9 As shown, the outer diameter of the packing pack 821 contacts the packing sleeve 84, and the inner diameter of the packing pack 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 to cause liquid leakage and damage to the valve box; the packing sleeve 84 is a wear-resistant part and has an interference fit with the valve box 70. The hardness of the packing sleeve 84 is higher than that of the valve box. The packing sleeve 84 is provided to prevent the valve box 70 from being damaged due to friction of the packing pack 821, thereby extending the service life of the valve box.

[0135] For example, the inner and outer diameters of the packing sleeve pressure cap 85 are both provided with threads, the outer threads of the packing sleeve pressure cap 85 cooperate with the valve box 70, and the inner threads of the packing sleeve pressure cap 85 cooperate with the packing pressure cap 83. In order to prevent the packing sleeve pressure cap 85 from loosening when the plunger 81 reciprocates, the packing sleeve pressure cap 85 can be fixed to the valve box 70 by welding.

[0136] Fig. 9 The discharge side 70b of the hydraulic end is also shown. The suction side 70a of the valve box 70 is provided with an upper liquid hole 700, and the discharge side 70b is provided with a discharge hole 7005. For example, the upper liquid hole 700 is connected to the upper water manifold, and low-pressure liquid flows inside; the discharge hole 7005 is connected to the discharge flange, and high-pressure liquid flows inside.

[0137] Fig. 9 Also shown is the body 77 of the valve box 70. The valve box 70 includes the body 77 and the inner cavity 07.

[0138] For example, Figure 8 and Fig. 9 As 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 pressure cap 20 is connected to the valve box 70 via the suction side thread 7001. The pressure cap 50 is connected to the valve box 70 via the discharge side thread 7002. The packing sleeve pressure cap 85 is connected to the valve box 70 via the plunger side thread 7003.

[0139] For example, the first valve component V1 and the second valve component V2 are both one-way valves. Fig. 9 As shown, the first valve assembly V1 and the second valve assembly V2 can be interchangeable. For example, the second valve assembly V2 is placed vertically, 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.

[0140] like Figure 4 and Fig. 9 As shown, for the first valve assembly V1, the valve seat 1c is arranged in the valve seat groove 1013 of the gland 10, and the left side of the gland 10 serves as the base of the valve seat 1c, which is used to fix the valve seat 1c. For example, the gland 10 cooperates with the valve body 1a, the seal 1b, the spring 1d and the spring bracket 1e to form a one-way 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 box 70; when the plunger advances, the valve body 1a closes, preventing the low-pressure liquid from entering the valve box 70.

[0141] For example, refer to Fig. 9 , taking the fluid entering the hydraulic end as fracturing fluid as an example, the working principle of the hydraulic end is as follows.

[0142] When sucking liquid, the plunger 81 returns (translates to the left), the first valve assembly V1 opens, the second valve assembly V2 closes, and the fracturing fluid flows from the suction manifold through the upper liquid hole 700, the secondary flow channel 1022, and the main flow channel 1021 into the alternating chamber 07b until the alternating chamber 07b is filled with fracturing fluid. At this time, the liquid in the inner chamber 07 is a low-pressure liquid.

[0143] When discharging the liquid, the plunger 81 moves (translates to the right), the first valve assembly V1 is closed, the second valve assembly V2 is opened, and the fracturing fluid flows from the alternating chamber 07b into the high-pressure chamber 07c and is discharged through the discharge hole 7005. At this time, the liquid in the inner chamber 07 is a high-pressure liquid.

[0144] Fig.10 A schematic diagram of the intersection of the inner cavities of a valve box in a hydraulic end provided in an embodiment of the present disclosure. Fig.10 (a) is a cross-sectional view of the inner cavity of the valve box along the XY plane. Fig.10 (b) is a schematic diagram of the YZ plane of the inner cavity of the valve box. Fig.11 A schematic diagram of the intersection of the inner cavities of another valve box in a hydraulic end provided in an embodiment of the present disclosure. Fig.11 (a) is a cross-sectional view of the inner cavity of the valve box along the XY plane. Fig.11 (b) is a schematic diagram of the YZ plane of the inner cavity of the valve box.

[0145] Fig.12 A schematic diagram of a second valve assembly in a hydraulic end provided in an embodiment of the present disclosure. Fig.12 As shown, the valve body 2a includes a boss a1 and a claw a2. The function of the boss a1 includes limiting the spring 2d to prevent the spring 2d from radial movement. The function of the boss a1 also includes limiting the opening height of the valve body 2a. When the second valve assembly V2 is opened, the boss a1 of the valve body 2a is in rigid contact with the boss of the discharge gland 40 to achieve a uniform opening height each time.

[0146] like Fig.12 As shown, the inner hole of the base 2f is in clearance with the claw a2, which guides the claw a2 and prevents the valve body 2a from being deflected under the impact of high-pressure liquid; the valve seat 2c and the base 2f are split structures, and the hardness of the base 2f is higher than that of the base 2c, so as to prevent the inclined surface of the valve seat 2c from being worn when the valve body 2a hits the valve seat 2c, avoid wearing the valve seat 2c and causing poor sealing, and also avoid reducing the service life of the valve seat and the valve body.

[0147] The structure and function of the first valve assembly can refer to the above description. The difference is that the boss of the valve body 1a is in rigid contact with the boss of the spring support.

[0148] Fig.13 A schematic diagram of a valve box on the discharge side of a hydraulic end provided in accordance with an embodiment of the present disclosure.

[0149] Fig.14 A schematic diagram of a sealing structure on the discharge side of a hydraulic end provided in an embodiment of the present disclosure.

[0150] Fig.15 A schematic diagram of a valve box on the suction side of a hydraulic end provided in accordance with an embodiment of the present disclosure. Fig.16 A schematic diagram of a sealing structure on the suction side of a hydraulic end provided in an embodiment of the present disclosure.

[0151] Fig.12 The sealing member 1021 is shown, and the sealing member 1021 includes a sealing ring, and a sealing groove is provided at a corresponding position of the base 2f. Fig.12 and Fig.13 As shown, a sealing member 1021 is provided to achieve sealing between the second valve assembly V2 and the valve box 70 .

[0152] Fig.13 A sealing groove 901 is shown, Fig.14 A seal 902 is shown. The seal 902 is provided to achieve sealing of the high pressure chamber of the inner chamber.

[0153] Fig.15 A sealing groove 903 is shown, Fig.16 A seal 904 is shown. The seal 904 is provided to achieve sealing of the low pressure chamber of the inner chamber.

[0154] The hydraulic end provided by the embodiments of the present disclosure has at least one of the following effects.

[0155] 1) The stress concentration effect in the inner cavity is significantly improved.

[0156] The embodiment of the present disclosure provides a valve box at the hydraulic end where the inner cavities intersect each other without a right angle, and the transition at the inner cavities intersecting each other is smooth. The shape design is performed at the position where stress concentration is most likely to occur. The intersection is in a bell-mouth shape and has no stress concentration point. From a mechanical analysis, the stress concentration effect is significantly improved.

[0157] 2) Simple structure and strong sealing.

[0158] The valve box of the hydraulic end provided in the embodiment of the present disclosure is an integral structure, which is tightly sealed and resistant to high pressure, uses fewer seals and does not require bolts, has a simple and compact structure, and has a low risk of valve box leakage.

[0159] 3) Easy maintenance.

[0160] In the hydraulic end provided by the embodiment of the present disclosure, the axis of the plunger coincides with the first axis (horizontal axis) of the valve box, and there is a pressure cap on the suction side (the axis of the pressure cap coincides with the axis of the plunger, and the pressure cap is removable), and maintenance can be carried out according to the normal operations of the well site.

[0161] The embodiment of the present disclosure further provides a plunger pump, comprising any of the above-mentioned hydraulic ends. Since the gland 10 is located at the suction side 70a of the hydraulic end, the gland 10 can also be called a suction gland.

[0162] For example, the gland 10, the hydraulic end including the gland 10, and the plunger pump can be applied to fracturing / cementing equipment in oil and gas fields.

[0163] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present disclosure, which should be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be based on the protection scope of the claims.

Claims

1. A gland, comprising: A body, the body is cylindrical, and 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 extension direction of the axis of the body; A plurality of secondary flow channels, each of which is in communication with the primary flow channel; A first opening, located at the first end and communicated with the main flow channel; as well as A plurality of second openings are located on the side of the body, and the secondary flow channel is connected to at least one of the plurality of second openings. The gland further comprises a leakage channel and a first leakage port and a second leakage port located at two ends of the leakage channel, wherein the first leakage port is located at the side surface of the body, and the second leakage port is located at the end surface of the second end of the body. The main flow channel is located on the axis of the body, and the aperture of the main flow channel is larger than the aperture of the secondary flow channel.

2. The gland according to claim 1, wherein: The main flow channel does not penetrate the body along the axis of the body.

3. The gland according to claim 1, wherein: The shape of the first drain port is different from the shape of the second drain port.

4. The gland according to claim 1, wherein: The plurality of second openings are evenly distributed in a circumferential direction of the body.

5. The gland according to claim 1, wherein: The secondary flow channel is arranged obliquely relative to the primary flow channel.

6. The gland according to claim 5, wherein: The acute angle between the center line of the secondary flow channel and the center line of the primary flow channel is in the range of 20-80 degrees.

7. The gland according to claim 5, wherein: The distance between the secondary flow channel and the axis of the body gradually increases in a direction from the first end to the second end.

8. The gland according to any one of claims 1 to 7, wherein: The leakage flow channel is not communicated with the main flow channel, and is not communicated with the secondary flow channel.

9. The gland according to any one of claims 1 to 7, wherein: The first drain port is located on a side of the side surface close to the end surface of the first end.

10. The gland according to any one of claims 1 to 7, further comprising a valve seat groove, wherein: The valve seat groove is located at the first end and communicated with the main flow channel, and the valve seat groove has a relief groove on a side away from the first end.

11. The gland according to any one of claims 1 to 7, further comprising a first sealing position and a second sealing position, wherein: The first sealing position is configured to set a first sealing ring, the second sealing position is configured to set a second sealing ring, the first sealing position and the second sealing position are both located on the side, and the first drain port is located between the first sealing position and the second sealing position.

12. The gland according to any one of claims 1 to 7, further comprising a first sealing groove and a second sealing groove, wherein: The first sealing groove is configured to accommodate a first sealing ring, the second sealing groove is configured to accommodate a second sealing ring, the first sealing groove and the second sealing groove are both located on the side surface, and the first drain port is located between the first sealing groove and the second sealing groove.

13. The gland according to any one of claims 1 to 7, further comprising a drawing hole, wherein: The pulling hole is located at the second end of the body, and the pulling hole is not connected to the second drain port.

14. The gland according to claim 13, wherein: The pulling hole is located on the axis of the body.

15. A hydraulic end comprising the gland according to any one of claims 1-14.

16. The fluid end of claim 15, further comprising: The valve box comprises an inner cavity, wherein the inner cavity comprises a low-pressure cavity, an alternating cavity and a high-pressure cavity; Among them, the pressure cover is located in the low-pressure chamber, the inner chamber of the valve box is an inverted T-shaped structure, the alternating chamber and the low-pressure chamber are arranged along the extension direction of the first axis of the inner chamber, the alternating chamber and the high-pressure chamber are arranged along the extension direction of the second axis of the inner chamber, and the first axis intersects with the second axis.

17. The fluid end according to claim 16, wherein: The valve box has an upper liquid hole, and the upper liquid hole and the high-pressure chamber are staggered in the extending direction of the first axis.

18. The fluid end of claim 16, further comprising a first valve assembly, wherein: The first valve assembly is configured to be opened to connect the low-pressure chamber and the alternating chamber or to be closed to separate the low-pressure chamber and the alternating chamber. The first valve assembly includes a spring bracket, which is a hollow structure and is limited by an inclined surface with the valve box.

19. The fluid end of claim 16, wherein: The intersection of the inner cavity includes a first sub-cavity and a second sub-cavity, the first sub-cavity and the second sub-cavity are arranged along the extension direction of the second axis, the second sub-cavity is closer to the portion of the inner cavity extending along the first axis than the first sub-cavity, and the maximum size of the second sub-cavity in the extension direction of the second axis is greater than the maximum size of the first sub-cavity in the extension direction of the second axis. The size of the second sub-cavity in the extending direction of the first axis gradually increases from a position far from the first axis to a position close to the first axis.

20. The fluid end of claim 19, wherein: The valve box is provided with protective sleeves at positions corresponding to the first sub-cavity and the second sub-cavity.

21. The fluid end of claim 19, further comprising a second valve assembly, wherein: The second valve assembly is configured to be opened to connect the alternating chamber and the high-pressure chamber or to be closed to separate the alternating chamber and the high-pressure chamber. The second valve assembly and the second sub-chamber are located on opposite sides of the first sub-chamber.

22. A plunger pump comprising the hydraulic end according to any one of claims 15-21.

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