Hydraulic end of plunger pump and plunger pump

Abstract

The present application relates to a hydraulic end of a plunger pump, the hydraulic end comprising a suction port (10), wherein an inner wall of the suction port (10) is provided with a first threaded structure (12); a suction gland (20) is arranged in the suction port (10), and an outer wall of the suction gland (20) is provided with a second threaded structure (21); the second threaded structure (21) comprises a threaded engagement section (211) and a non-engagement section (212); the threaded engagement section (211) is connected to the first threaded structure (12); and the non-engagement section (212) is located between a starting end (200) of the second threaded structure (21) and a suction end face (11).

Description

plunger pump hydraulic end and plunger pump

[0001] Related applications

[0002] This application claims priority to Chinese patent application filed on March 28, 2025, with application number 2025205713117, entitled "Hydraulic End of Plunger Pump and Plunger Pump", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of oilfield fracturing equipment technology, and in particular to the hydraulic end of a plunger pump and the plunger pump itself. Background Technology

[0004] As a key piece of equipment in oil and gas field fracturing operations, the plunger pump's core function is to convert fracturing fluid, especially liquids with a certain viscosity, from atmospheric pressure into high-pressure, high-flow-rate fracturing fluid for effective injection into the formation. A plunger pump typically consists of two main parts: a hydraulic end and a power end. These two parts work together to convert mechanical energy into liquid pressure energy.

[0005] However, in the actual use of plunger pumps, the valve box, as a high-value consumable component, often has a service life that is a key factor restricting the overall performance of the plunger pump. Especially at the threaded section of the valve box's suction end, due to long-term alternating loads, cracks are highly likely to occur at the beginning of the threads. These thread cracks not only affect the normal operation of the valve box but also rapidly expand over time, eventually leading to the scrapping of the entire valve box and severely shortening its service life.

[0006] In summary, the contact stress and stress concentration at the starting position of the thread at the suction end of the valve box are relatively large, leading to cracking at the starting position of the thread at the suction end. Summary of the Invention

[0007] According to various embodiments of this application, a hydraulic end of a plunger pump and a plunger pump are provided.

[0008] A hydraulic end of a plunger pump, comprising:

[0009] The suction port has a first threaded structure on its inner wall;

[0010] A suction cap is disposed inside the suction port. The outer wall of the suction cap is provided with a second thread structure, which includes a threaded engagement section and a non-engaging section.

[0011] The threaded engagement section is connected to the first threaded structure;

[0012] The non-engaging section is located between the starting end and the suction end face of the second thread structure.

[0013] In one embodiment, an axial gap is formed between the non-engaging section and the first threaded structure.

[0014] In one embodiment, the axial distance of the first thread structure is N1, the axial distance of the thread engagement section is N2, and N1 > N2.

[0015] In one embodiment, the hydraulic end of the plunger pump further includes a discharge port and a discharge cap; the inner wall of the discharge port is provided with a third thread structure, and the outer wall of the discharge cap is provided with a fourth thread structure;

[0016] The fourth thread structure includes a threaded engagement section and a non-engaging section, the non-engaging section being located between the starting end and the discharge end face of the fourth thread structure; an axial gap is formed between the third thread structure and the non-engaging section.

[0017] In one embodiment, the hydraulic end of the plunger pump further includes a packing port and a packing cap; the inner wall of the packing port is provided with a fifth thread structure, and the outer wall of the packing cap is provided with a sixth thread structure;

[0018] The sixth thread structure includes a threaded engagement section and a non-engaging section, the non-engaging section being located between the starting end of the sixth thread structure and the packing end face; an axial clearance is formed between the fifth thread structure and the non-engaging section.

[0019] In one embodiment, the axial length of the non-engaging section of the suction cap, discharge cap, or packing cap is 1-2 times the thread pitch of the corresponding threaded engagement section.

[0020] In one embodiment, the effective length of the threaded engagement section of the suction cap does not exceed 90% of the total thread length of the first thread structure provided on the inner wall of the suction port.

[0021] In one embodiment, the effective length of the threaded engagement section of the discharge cap does not exceed 90% of the total thread length of the third thread structure provided on the inner wall of the discharge port.

[0022] In one embodiment, the effective length of the threaded engagement section of the packing cap does not exceed 90% of the total thread length of the fifth thread structure provided on the inner wall of the packing port.

[0023] In one embodiment, a transition chamfer is provided between the non-engaging section of the suction cap, discharge cap, or packing cap and the corresponding threaded engagement section.

[0024] In one embodiment, the non-engaging section is a transition surface.

[0025] In one embodiment, the outer wall of the non-engaging section is a smooth cylindrical surface.

[0026] In one embodiment, the outer wall of the non-engaging section of the intake cap, discharge cap, or packing cap is provided with a friction-reducing coating, the material of which is polytetrafluoroethylene or molybdenum disulfide.

[0027] In one embodiment, the suction cap and the suction port are made of stainless steel or alloy steel.

[0028] In one embodiment, a plunger pump includes a plunger pump hydraulic end as described above, the plunger pump hydraulic end including a plunger;

[0029] The plunger pump also includes a power end, and the plunger is connected to the power end.

[0030] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features, objects, and advantages of this application will become apparent from the specification, drawings, and claims. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the disclosed drawings without creative effort.

[0032] To better describe and illustrate the embodiments or examples of this application disclosed herein, reference may be made to one or more accompanying drawings. Additional details or examples used to describe the drawings should not be considered as limiting the scope of any of the best mode of the embodiments or examples currently described.

[0033] Figure 1 is a schematic diagram of the hydraulic end of a plunger pump according to one or more embodiments.

[0034] Figure 2 is a schematic diagram of the inhalation port according to one or more embodiments. Detailed Implementation

[0035] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0041] Referring to Figures 1 and 2, Figure 1 is a structural schematic diagram of the hydraulic end of a plunger pump according to one or more embodiments. Figure 2 is a structural schematic diagram of the suction port 10 according to one or more embodiments. One embodiment of this application provides a hydraulic end for a plunger pump, including a suction port 10 and a suction cap 20, used to solve the problem of cracking at the starting position of the thread at the suction end of the valve box.

[0042] In this embodiment, the suction cap 20 is disposed within the suction port 10, and the inner wall of the suction port 10 is provided with a first threaded structure 12. The first threaded structure 12 is used for threaded connection with the outer wall of the suction cap 20 to achieve a tight seal and fixation.

[0043] The suction cap 20 is disposed within the suction port 10, and the outer wall of the suction cap 20 is provided with a second threaded structure 21. The second threaded structure 21 includes a threaded engagement section 211 and a non-engaging section 212. The threaded engagement section 211 is connected to the first threaded structure 12. The non-engaging section 212 is located between the starting end 200 of the second threaded structure 21 and the suction end face 11.

[0044] In this embodiment, the threaded engagement section 211 is located in the middle and rear portion of the outer wall of the suction cap 20. The thread shape and pitch of the threaded engagement section 211 match the first thread structure 12 to achieve a tight threaded connection. The non-engaging section 212 is located between the starting end 200 of the second thread structure 21 and the suction end face 11, that is, a non-engaging portion is reserved between the thread starting end 200 of the suction cap 20 and the suction end face 11 of the suction port 10.

[0045] Since the thread start end 200 is often directly in close contact with the suction end face 11 of the suction port 10, stress concentration occurs in this area, making it prone to cracking. By reserving a non-engaging portion, the stress at the thread start end 200 is effectively dispersed, avoiding the problem of stress concentration and thus preventing cracking.

[0046] In one embodiment, the suction port 10 is used to guide fracturing fluid into the plunger pump. A suction cap 20 is disposed inside the suction port 10 to ensure the fracturing fluid is sealed under high pressure and prevent leakage. In this embodiment, the suction cap 20 and the suction port 10 are made of high-strength, corrosion-resistant materials, such as stainless steel or alloy steel.

[0047] In one embodiment, the non-engaging portion can be a smooth transition surface, the purpose of which is to reduce the direct contact area between the thread start end 200 and the suction end face 11 of the suction port 10, thereby reducing the stress level. In this embodiment, the size and shape of the non-engaging portion can be adjusted according to the specific usage requirements of the hydraulic end of the plunger pump.

[0048] As described above, by reserving a non-engaging portion between the thread start end 200 of the suction cap 20 and the suction end face 11 of the suction port 10, stress is effectively dispersed, the risk of stress concentration is reduced, and the problem of cracking at the thread start position is avoided, thereby extending the service life of the hydraulic end of the plunger pump.

[0049] Referring to Figure 2, which is a structural schematic diagram of the intake port 10 according to one or more embodiments, in one embodiment, an axial gap is formed between the non-engaging section 212 and the first threaded structure 12, i.e., the portion that first contacts the intake port 10. Since the non-engaging section 212 has no threads but forms a smooth transition surface to create the axial gap with the first threaded structure 12, stress concentration at the threaded connection is effectively reduced, especially under high-pressure operating environments, significantly reducing the risk of cracking.

[0050] In one embodiment, the axial distance of the first threaded structure 12 is N1.

[0051] The first thread structure 12 has an axial distance of N1, which provides sufficient space for the non-engaging section 212 to ensure that the suction cap 20 can smoothly enter the suction port 10 during assembly, avoiding excessive stress at the beginning of the thread.

[0052] In one embodiment, the axial distance of the threaded engagement section 211 is N2, and N1 > N2.

[0053] The axial distance of the threaded engagement section 211 of the second threaded structure 21 is N2. In this embodiment, N1 > N2, that is, the distance from the thread termination end of the first threaded structure 12 to the suction end face 11 of the suction port 10, that is, the axial distance of the first threaded structure 12 is longer than the distance from the thread termination end to its starting end 200 of the second threaded structure 21, that is, the axial distance of the threaded engagement section 211 is longer, ensuring that a stable axial gap can be formed between the non-engaging section 212 and the suction port 10, further dispersing the stress at the threaded connection, thereby reducing the risk of cracking.

[0054] In one embodiment, the axial length of the non-engaging section 212 of the suction cap 20 is 1-2 times the thread pitch of the corresponding threaded engagement section 211.

[0055] The non-engaging section 212 of the suction cap 20 is located at the front end of the threaded engagement section 211, i.e., the part that first contacts the suction port 10. The axial length of the non-engaging section 212 of the suction cap 20 is 1-2 times the thread pitch of the corresponding threaded engagement section 211. By increasing the length of the non-engaging section 212 of the suction cap 20, the stress at the threaded connection is further dispersed, reducing stress concentration, thereby improving the stability and durability of the threaded connection between the suction cap 20 and the suction port 10.

[0056] In one embodiment, the effective length of the threaded engagement section 211 of the suction cap 20 does not exceed 90% of the total thread length of the threaded structure provided on the inner wall of the corresponding port.

[0057] The total thread length refers to the complete length of the first thread structure 12 provided on the inner wall of the suction port 10, which is the distance from the thread start end 200 to the thread end. The effective length refers to the length of the thread engagement section 211 that actually participates in the threaded connection, that is, from the position where the suction cap 20 starts to contact the inner wall of the suction port 10 and generate thread engagement to the position where the thread engagement section 211 ends.

[0058] By setting the effective length of the thread engagement section 211 to no more than 90% of the total thread length, a stable threaded connection can be formed between the suction cap 20 and the suction port 10, while avoiding stress concentration and damage caused by over-tightening.

[0059] In one embodiment, a transition chamfer is provided between the non-engaging section 212 of the suction cap 20 and the corresponding threaded engagement section 211.

[0060] A transition chamfer is provided between the non-engaging section 212 and the threaded engagement section 211 of the suction cap 20. The transition chamfer can disperse the stress at the threaded connection and reduce stress concentration. In this embodiment, the size and shape of the transition chamfer should be reasonably selected according to specific usage requirements.

[0061] In one embodiment, the outer wall of the non-engaging section 212 is a smooth cylindrical surface to reduce friction and wear with the inner wall of the suction port 10, thereby improving durability.

[0062] In one embodiment, the outer wall of the non-engaging section 212 of the intake cap 20, discharge cap 40, or packing cap 60 is provided with a friction-reducing coating.

[0063] The outer wall of the non-engaging section 212 of the suction cap 20 is provided with an anti-friction coating to further reduce friction and wear, and improve the smoothness and durability of the assembly between the suction cap 20 and the suction port 10. In this embodiment, the anti-friction coating is made of polytetrafluoroethylene (PTFE) or molybdenum disulfide (MoS2). Both PTFE and MoS2 materials have good lubrication and anti-wear properties, and can significantly reduce the coefficient of friction and wear rate.

[0064] The outer wall of the non-engaging section 212 of the discharge cap 40 is provided with a friction-reducing coating, and the outer wall of the non-engaging section 212 of the packing cap 60 is also provided with a friction-reducing coating.

[0065] In this embodiment, the anti-friction coating can be applied to the outer wall of the non-meshing section 212 by methods such as spraying, dipping, or brushing. The thickness and uniformity of the coating should be reasonably controlled according to the actual application requirements.

[0066] Referring to Figure 1, which is a structural schematic diagram of the hydraulic end of a plunger pump according to one or more embodiments. In some embodiments, the hydraulic end of the plunger pump further includes a discharge port 30 and a discharge cap 40.

[0067] The inner wall of the discharge port 30 is provided with a third thread structure (not shown in the figure), which is consistent with the structure of the first thread structure 12. The outer wall of the discharge cap 40 is provided with a fourth thread structure (not shown in the figure), which is consistent with the structure of the second thread structure 21. The fourth thread structure includes a threaded engagement section 211 and a non-engaging section 212. The non-engaging section 212 is located between the starting end 200 of the fourth thread structure and the discharge end face, that is, the part that first contacts the discharge port 30.

[0068] In one embodiment, an axial gap is formed between the third threaded structure and the non-engaging section 212, allowing the discharge cap 40 to have a certain axial movement space during assembly, thereby making it easier to achieve correct thread engagement and reducing resistance and friction during assembly.

[0069] Referring to Figure 1, which is a structural schematic diagram of the hydraulic end of a plunger pump according to one or more embodiments. In some embodiments, the hydraulic end of the plunger pump further includes a packing port 50 and a packing cap 60.

[0070] The inner wall of the packing port 50 is provided with a fifth thread structure (not shown in the figure), which is identical to the first thread structure 12. The outer wall of the packing cap 60 is provided with a sixth thread structure (not shown in the figure), which is identical to the second thread structure 21. The sixth thread structure includes a threaded engagement section 211 and a non-engaging section 212. The non-engaging section 212 is located between the starting end 200 of the sixth thread structure and the packing end face, i.e., the part that first contacts the packing port 50.

[0071] In one embodiment, an axial clearance is formed between the fifth threaded structure and the non-engaging section 212, allowing the packing cap 60 to have a certain axial movement space during assembly, which facilitates thread engagement and reduces resistance and friction during assembly.

[0072] In one embodiment, the axial length of the non-engaging section 212 of the discharge cap 40 or packing cap 60 is 1-2 times the thread pitch of the corresponding threaded engagement section 211.

[0073] The axial length of the non-engaging section 212 of the packing cap 40 is 1-2 times the thread pitch of the corresponding threaded engagement section 211. Similarly, the axial length of the non-engaging section 212 of the packing cap 60 is 1-2 times the thread pitch of the corresponding threaded engagement section 211. These settings further reduce friction and resistance during assembly while ensuring the stability of the threaded engagement section 211.

[0074] In one embodiment, the effective length of the threaded engagement section 211 of the discharge cap 40 does not exceed 90% of the total thread length of the third thread structure provided on the inner wall of the discharge port 30. This configuration avoids stress concentration and damage caused by over-tightening, improving the stability and sealing performance of the connection.

[0075] In one embodiment, the effective length of the threaded engagement section 211 of the packing cap 60 does not exceed 90% of the total thread length of the fifth thread structure provided on the inner wall of the packing port 50. This configuration avoids stress concentration and damage caused by over-tightening, improving the stability and sealing performance of the connection.

[0076] In one embodiment, a transition chamfer is provided between the non-engaging section 212 of the discharge cap 40 or packing cap 60 and the threaded engagement section 211.

[0077] A transition chamfer is provided between the non-engaging section 212 and the threaded engagement section 211 of the discharge cap 40. Similarly, a transition chamfer is provided between the non-engaging section 212 and the threaded engagement section 211 of the packing cap 60. These features are used to distribute stress at the threaded connection.

[0078] In one embodiment, the outer wall of the non-engaging section 212 of the discharge cap 40 is a smooth cylindrical surface to reduce friction and wear between the non-engaging section 212 of the discharge cap 40 and the inner wall of the discharge port 30. Similarly, the outer wall of the non-engaging section 212 of the packing cap 60 is a smooth cylindrical surface to reduce friction and wear between the non-engaging section 212 of the packing cap 60 and the inner wall of the packing port 50.

[0079] In this embodiment, the outer wall of the non-engaging section 212 of the discharge cap 40 is provided with a friction-reducing coating. The material of the friction-reducing coating is polytetrafluoroethylene (PTFE) or molybdenum disulfide (MoS2), which further reduces friction and wear, and improves assembly smoothness and durability.

[0080] As described above, the introduction of non-meshing section 212, axial clearance, transition chamfer and anti-friction coating effectively reduces friction and resistance during assembly, improves connection stability and sealing performance, and extends the service life of the hydraulic end of the plunger pump.

[0081] In this embodiment, a plunger pump is also provided, including the plunger pump hydraulic end as described above, wherein the plunger pump hydraulic end includes a plunger; the plunger pump also includes a power end, wherein the plunger is connected to the power end.

[0082] The aforementioned plunger pump effectively disperses stress, reduces the risk of stress concentration, and avoids the problem of cracking at the thread start position by reserving a non-meshing portion between the thread start end 200 of the suction cap 20 and the suction end face 11 of the suction port 10, thereby extending the service life of the plunger pump.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0084] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A hydraulic end of a plunger pump, characterized in that, include: A suction port (10) is provided with a first threaded structure (12) on its inner wall; A suction cap (20) is disposed inside the suction port (10). The outer wall of the suction cap (20) is provided with a second thread structure (21). The second thread structure (21) includes a threaded engagement section (211) and a non-engaging section (212). The threaded engagement section (211) is connected to the first threaded structure (12); The non-engaging section (212) is located between the starting end (200) of the second threaded structure (21) and the suction end face (11).

2. The hydraulic end of the plunger pump according to claim 1, characterized in that, An axial gap is formed between the non-engaging section (212) and the first threaded structure (12).

3. The hydraulic end of the plunger pump according to claim 2, characterized in that, The axial distance of the first thread structure (12) is N1, and the axial distance of the thread engagement section (211) is N2, and N1 > N2.

4. The hydraulic end of the plunger pump according to claim 1, characterized in that, The hydraulic end of the plunger pump also includes a discharge port (30) and a discharge cap (40); the inner wall of the discharge port (30) is provided with a third thread structure, and the outer wall of the discharge cap (40) is provided with a fourth thread structure; The fourth thread structure includes a thread engagement section (211) and a non-engaging section (212), the non-engaging section (212) being located between the starting end (200) and the discharge end face of the fourth thread structure; an axial gap is formed between the third thread structure and the non-engaging section (212).

5. The hydraulic end of the plunger pump according to claim 1, characterized in that, The hydraulic end of the plunger pump also includes a packing port (50) and a packing cap (60); the inner wall of the packing port (50) is provided with a fifth thread structure, and the outer wall of the packing cap (60) is provided with a sixth thread structure. The sixth thread structure includes a thread engagement section (211) and a non-engaging section (212), the non-engaging section (212) being located between the starting end (200) of the sixth thread structure and the packing end face; an axial gap is formed between the fifth thread structure and the non-engaging section (212).

6. The hydraulic end of the plunger pump according to any one of claims 2-5, characterized in that, The axial length of the non-engaging section (212) of the intake cap (20), discharge cap (40) or packing cap (60) is 1-2 times the thread pitch of the corresponding thread engagement section (211).

7. The hydraulic end of the plunger pump according to claim 2, characterized in that, The effective length of the threaded engagement section (211) of the suction cap (20) does not exceed 90% of the total thread length of the first thread structure (12) provided on the inner wall of the suction port (10).

8. The hydraulic end of the plunger pump according to claim 4, characterized in that, The effective length of the threaded engagement section (211) of the discharge cap (40) does not exceed 90% of the total thread length of the third thread structure provided on the inner wall of the discharge port (30).

9. The hydraulic end of the plunger pump according to claim 5, characterized in that, The effective length of the threaded engagement section (211) of the packing cap (60) does not exceed 90% of the total thread length of the fifth thread structure provided on the inner wall of the packing port (50).

10. The hydraulic end of the plunger pump according to any one of claims 2-5, characterized in that, A transition chamfer is provided between the non-engaging section (212) of the intake cap (20), discharge cap (40) or packing cap (60) and the corresponding threaded engagement section (211).

11. The hydraulic end of the plunger pump according to any one of claims 2-5, characterized in that, The non-meshing section (212) is a transition surface.

12. The hydraulic end of the plunger pump according to claim 11, characterized in that, The outer wall of the non-engaging section (212) is a smooth cylindrical surface.

13. The hydraulic end of the plunger pump according to any one of claims 2-5, characterized in that, The outer wall of the non-engaging section (212) of the intake cap (20), discharge cap (40) or packing cap (60) is provided with a friction-reducing coating, the material of which is polytetrafluoroethylene or molybdenum disulfide.

14. The hydraulic end of the plunger pump according to any one of claims 2-5, characterized in that, The suction cap (20) and the suction port (10) are made of stainless steel or alloy steel.

15. A plunger pump, characterized in that, Includes the hydraulic end of a plunger pump as described in any one of claims 1-14, wherein the hydraulic end of the plunger pump includes a plunger; The plunger pump also includes a power end, and the plunger is connected to the power end.

Images