Reciprocating plunger pump

Abstract

The application relates to a reciprocating plunger pump, which comprises a fluid end assembly and a power end assembly, and further comprises: the fluid end assembly comprises a plunger and a packing ring for sealing the plunger; the power end assembly comprises a cross head, a pull rod and a pull rod oil seal assembly, one end of the pull rod is connected with the cross head, and the other end of the pull rod is connected with the plunger; an auxiliary sealing piece is arranged at the connecting position of a fluid end assembly shell and a power end assembly shell, the outer diameter of the auxiliary sealing piece is larger than the outer diameters of the plunger and the pull rod, and an axial gap is formed between the auxiliary sealing piece and the packing ring. By arranging the auxiliary sealing piece, when the packing ring fails to seal, the high-pressure working medium in the fluid end can be effectively prevented from being sprayed back to the power end, lubricating oil is prevented from being polluted and transmission components are prevented from being damaged, and the reliability and service life are improved. Meanwhile, the auxiliary sealing piece can isolate external sand and impurities from invading the connecting position of the fluid end and the power end, abnormal wear is reduced, and the failure rate and maintenance cost are reduced.

Description

Technical Field

[0001] This application relates to the field of oil and gas field fracturing equipment technology, and in particular to reciprocating plunger pumps. Background Technology

[0002] With the development of oil and gas field development equipment technology, reciprocating plunger pumps, as core power components for operations such as cementing, acidizing, and fracturing, are increasingly demanding in terms of reliability and ease of maintenance. Traditional plunger pumps have plungers directly fixed to the crosshead via connecting bolts, driven by a linkage mechanism for reciprocating motion. A multi-stage sealing structure, consisting of a tie rod oil seal seat, dustproof seat, and seals, is used between the plunger and the housing to prevent external impurities from entering the power end.

[0003] However, seal failure poses a risk of media backflow. Due to the high-frequency frictional characteristics of the reciprocating plunger, the packing of the sealing plunger in the hydraulic end assembly is extremely prone to wear. When the packing fails, the high-pressure working medium (such as fracturing fluid or acid) in the hydraulic end will leak along the plunger surface, directly impacting the sealing components of the power end assembly. Traditional sealing structures lack a secondary barrier mechanism against high-pressure media, allowing the leaked medium to quickly penetrate the dust seal and oil seal, intruding into the power end assembly. This leads to lubricant contamination, deterioration of lubrication performance, corrosion of gearbox bearings, abnormal wear of transmission components, and ultimately, overall failure of the power end assembly.

[0004] In summary, traditional plunger pumps suffer from problems such as easy wear of the packing, leading to leakage and backflow of the working medium, and contamination of the power end. Utility Model Content

[0005] Therefore, it is necessary to provide a reciprocating piston pump to address the problems of easy wear of the packing gland in traditional piston pumps, which leads to leakage and backflow of the working medium and contamination of the power end.

[0006] A reciprocating piston pump includes a hydraulic end assembly and a power end assembly, and further includes:

[0007] The hydraulic end assembly includes a plunger and a packing gland that seals the plunger;

[0008] The power end assembly includes a crosshead, a tie rod, and a tie rod oil seal assembly. One end of the tie rod is connected to the crosshead, and the other end is connected to the plunger.

[0009] An auxiliary seal is disposed at the connection between the hydraulic end assembly housing and the power end assembly housing. The outer diameter of the auxiliary seal is larger than the outer diameter of the plunger and the pull rod. An axial clearance exists between the auxiliary seal and the packing.

[0010] In one embodiment, the auxiliary seal is fixed between the plunger and the pull rod, and the auxiliary seal is sleeved on the end where the plunger and the pull rod connect.

[0011] In one embodiment, the auxiliary seal includes a first section, a second section, and a third section. The first section is located at one end of the pull rod near the plunger and extends in a direction perpendicular to the axial direction of the pull rod. The second section is connected to the first section and extends in the axial direction of the pull rod. The third section is connected to the second section and extends in a direction perpendicular to the axial direction of the pull rod.

[0012] In one embodiment, the first segment extends in a direction perpendicular to the axial direction of the pull rod, and its length is greater than the diameter of the plunger.

[0013] In one embodiment, the second segment extends along the axial direction of the pull rod, covering the connection area between the plunger and the pull rod.

[0014] In one embodiment, the angle between the second segment and the first segment is a right angle, and there is a gap between the second segment and the plunger.

[0015] In one embodiment, the third segment extends in a direction perpendicular to the axial direction of the pull rod, and its length is greater than the diameter of the pull rod.

[0016] In one embodiment, the pull rod protrudes outward on the side away from its axis, the third segment covers the protrusion, and the portion of the third segment that contacts the protrusion is provided with an annular sealing ring.

[0017] In one embodiment, the auxiliary seal and the pull rod are integrally formed, and the auxiliary seal is formed by extending outward along the axial direction of the pull rod from the side away from its axis.

[0018] In one embodiment, the tie rod oil seal assembly includes a tie rod oil seal seat, a tie rod oil seal, and a tie rod oil seal baffle; the tie rod oil seal seat is fixed to the power end assembly housing, and the tie rod oil seal baffle is slidably connected to the tie rod oil seal seat.

[0019] The aforementioned reciprocating piston pump, by incorporating auxiliary seals, effectively prevents the high-pressure working medium from spraying back to the power end in the event of packing seal failure. This avoids contaminating the lubricating oil and damaging transmission components, thus improving reliability and service life. Simultaneously, the auxiliary seals isolate external mud and impurities from intruding into the connection between the hydraulic and power ends, reducing abnormal wear and lowering the failure rate and maintenance costs. Attached Figure Description

[0020] Figure 1 Schematic diagram of a partial structure of a reciprocating piston pump Figure 1 .

[0021] Figure 2Schematic diagram of a partial structure of a reciprocating piston pump Figure 2 .

[0022] In the diagram: 10. Hydraulic end assembly; 11. Plunger; 12. Packing;

[0023] 20. Power end assembly; 21. Crosshead; 22. Tie rod; 23. Tie rod oil seal assembly; 231. Tie rod oil seal seat; 232. Tie rod oil seal; 233. Tie rod oil seal baffle;

[0024] 30. Auxiliary sealing component; 31. First section; 32. Second section; 33. Third section. Detailed Implementation

[0025] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] In traditional plunger pump operation, the reciprocating motion of the plunger causes easy wear on the seals. If the packing at the hydraulic end is damaged, the high-pressure working medium will leak along the plunger, damaging the power-end seals and spraying back into the power-end assembly, contaminating the lubricating oil, and ultimately damaging the power-end assembly and gearbox assembly. Furthermore, the operating space at the packing is limited, and as a vulnerable part, it requires frequent replacement. Replacement necessitates disassembling the power-end seals first, making maintenance difficult.

[0032] See Figure 1 , Figure 1 A partial structural schematic diagram of a reciprocating plunger pump according to an embodiment of this application is shown.

[0033] To solve the above-mentioned technical problems, an embodiment of this application provides a reciprocating plunger pump, including a hydraulic end assembly 10, a power end assembly 20, and an auxiliary seal 30. The auxiliary seal 30 is disposed at the connection between the hydraulic end assembly 10 and the power end assembly 20 to form an anti-backflow structure, preventing the working medium leaking from the power end assembly 20 from splashing onto the hydraulic end assembly 10, avoiding contamination or damage, and improving safety in use.

[0034] In this embodiment, the hydraulic end assembly 10 includes a plunger 11 and a packing 12 for sealing the plunger 11. The power end assembly 20 includes a crosshead 21, a pull rod 22, and a pull rod oil seal assembly 23. One end of the pull rod 22 is connected to the crosshead 21, and the other end is connected to the plunger 11.

[0035] The reciprocating piston pump also includes an auxiliary seal 30, which is located at the connection between the housing of the hydraulic end assembly 10 and the housing of the power end assembly 20. The outer diameter of the auxiliary seal 30 is larger than the outer diameter of the piston 11 and the tie rod 22, and there is an axial clearance between the auxiliary seal 30 and the packing 12.

[0036] The hydraulic end assembly 10 is a component of the reciprocating plunger pump that enables liquid delivery. It mainly includes the plunger 11 and the packing 12 for sealing the plunger 11.

[0037] As the moving part of the reciprocating plunger pump, the plunger 11 performs reciprocating linear motion under the drive of the power end assembly 20, compressing the medium in the hydraulic end working chamber. The plunger 11 is made of high-strength, wear-resistant alloy steel, and its surface has surface hardness and smoothness, which can effectively reduce friction and wear between it and the seal, and improve the service life and working stability of the plunger 11.

[0038] Packing 12 is a component in the hydraulic end assembly 10 used to seal the plunger 11, and is made of a composite material with elastic and corrosion-resistant properties. Packing 12 is installed inside a packing 12 housing, which is fixed to the housing of the hydraulic end assembly 10. Through its own elastic deformation, packing 12 tightly adheres to the surface of the plunger 11, forming a sealing barrier to prevent leakage of high-pressure working media, such as fracturing fluid or acid, from the hydraulic end assembly 10.

[0039] The power end assembly 20 is the power source and motion transmission component of the reciprocating piston pump, mainly including the crosshead 21, the tie rod 22 and the tie rod oil seal assembly 23.

[0040] The crosshead 21 is a connecting component in the power-end assembly 20. It is connected to a power source, such as an electric motor or engine, via a linkage mechanism, converting the rotational motion of the power source into reciprocating linear motion. The crosshead 21 is made of high-strength cast iron or cast steel and contains internal sliding bearings to ensure smooth and flexible movement with the linkage mechanism and tie rod 22, reducing energy loss and mechanical wear. The crosshead 21 has sufficient strength and rigidity to withstand the enormous alternating loads generated during reciprocating motion, ensuring the reliability and stability of power transmission.

[0041] The pull rod 22 is a transmission component connecting the crosshead 21 and the plunger 11. One end of the pull rod 22 is fixedly connected to the crosshead 21, and the other end passes through the oil seal assembly and connects to the plunger 11. The pull rod 22 is made of high-strength alloy steel and undergoes a heat treatment process to give it excellent mechanical properties and fatigue resistance. The surface of the pull rod 22 is machined to ensure the fitting accuracy of the connection between it and the crosshead 21 and the plunger 11, reduce stress concentration at the connection point, and improve the connection strength and reliability.

[0042] The tie rod oil seal assembly 23 is mounted on the housing of the power end assembly 20 to seal the gap between the tie rod 22 and the housing of the power end assembly 20, preventing lubricating oil leakage from the power end assembly 20 and the entry of external impurities. The tie rod oil seal assembly 23 adopts a multi-seal structure, effectively preventing lubricating oil leakage and blocking external dust, mud, and other impurities from entering the interior of the power end assembly 20, protecting the internal transmission components from wear and corrosion.

[0043] An auxiliary seal 30 is installed at the connection between the housing of the hydraulic end assembly 10 and the housing of the power end assembly 20. The auxiliary seal 30 is made of a high-strength, corrosion-resistant metal material, such as stainless steel. The auxiliary seal 30 is fixed to the connection between the housing of the hydraulic end assembly 10 and the housing of the power end assembly 20 by means of bolts, welding, etc., to ensure stable installation.

[0044] The outer diameter of the auxiliary seal 30 is larger than the outer diameter of the plunger 11 and the pull rod 22, and there is an axial clearance between it and the packing 12. This axial clearance ensures that the plunger 11 and the pull rod 22 will not interfere with the auxiliary seal 30 during the axial reciprocating motion, and can block the high-pressure working medium leaking from the hydraulic end assembly 10 as well as external mud, sand, impurities, etc.

[0045] In the specific implementation process, when the power source of the power end assembly 20 is started, the rotational motion is transmitted to the crosshead 21 through the linkage mechanism. The crosshead 21 drives the pull rod 22 to perform reciprocating linear motion. The pull rod 22 then drives the plunger 11 to reciprocate within the hydraulic end assembly 10. As the plunger 11 reciprocates within the working chamber of the hydraulic end assembly 10, the volume of the working chamber changes periodically, thereby realizing the process of liquid intake and discharge, converting mechanical energy into pressure energy for transporting liquid.

[0046] When the high-pressure working medium leaks from the hydraulic end assembly 10, the auxiliary seal 30 acts as the first physical barrier, preventing the medium from directly backflowing into the power end assembly 20 and avoiding contamination and damage to components such as lubricating oil, gears, and bearings within the power end assembly 20. Simultaneously, the auxiliary seal 30 also prevents external mud, sand, and impurities from entering the connection between the hydraulic end assembly 10 and the power end assembly 20, reducing wear on components such as the plunger 11, tie rod 22, and seals, thereby improving the overall reliability and service life of the reciprocating plunger pump.

[0047] In this embodiment, the outer diameter of the auxiliary seal 30 is 20%, 21%, 22%, 23%, 24%, 25%, 27%, 28%, 29%, or 30% larger than the outer diameter of the plunger 11 or the pull rod 22. Specific values ​​can be adjusted adaptively according to usage requirements, and will not be elaborated here.

[0048] In this embodiment, the gap between the auxiliary seal 30 and the packing 12 can be 2mm, 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, etc. This gap value can be adjusted adaptively according to specific usage requirements, and will not be elaborated here.

[0049] In this embodiment, the axial distance between the auxiliary seal 30 and the packing 12 can be 60mm, 65mm, 70mm, 75mm, 80mm, 85mm, 90mm, etc. This axial distance can be adjusted adaptively according to specific usage requirements, and will not be elaborated here.

[0050] As described above, the auxiliary seal 30 acts as a physical barrier, effectively preventing the high-pressure working medium from the hydraulic end from spraying back to the power end when the packing 12 seal fails. This avoids contaminating the lubricating oil and damaging transmission components, significantly improving equipment reliability and service life. The auxiliary seal 30 can isolate external mud and impurities from intruding into the connection between the hydraulic end and the power end, reducing abnormal wear on the plunger 11, pull rod 22, and seals, thus lowering equipment failure rate and maintenance costs. Replacing the packing 12 does not require disassembling the power end seal, simplifying the operation process, shortening maintenance time, and reducing the workload of operators.

[0051] Combination Figure 1 As shown, Figure 1 This is a partial structural diagram of a reciprocating plunger pump provided in one embodiment of this application. In some embodiments, an auxiliary seal 30 is fixed between the plunger 11 and the pull rod 22, and the auxiliary seal 30 is sleeved on the end where the plunger 11 and the pull rod 22 are connected.

[0052] Specifically, the auxiliary seal 30 is a disc-shaped mudguard, which is fixed between the plunger 11 and the pull rod 22. The mudguard is sleeved on the end where the plunger 11 and the pull rod 22 are connected, which increases the sealing performance at the connection between the plunger 11 and the pull rod 22, reduces the risk of media leakage, and improves the overall sealing performance.

[0053] In this embodiment, the mudguard is made of fluororubber, which has excellent oil resistance, corrosion resistance, and high-temperature resistance. It maintains stable physical and chemical properties in the harsh working environment of the reciprocating plunger pump, ensuring that the sealing effect is not affected. Furthermore, fluororubber also has good elasticity and flexibility, allowing it to adapt to the minor deformations and vibrations of the plunger 11 and tie rod 22 during reciprocating motion, effectively reducing wear between the seal and connecting parts and extending service life.

[0054] In one embodiment, the auxiliary seal 30 includes a first section 31, a second section 32 and a third section 33. The first section 31 is located at one end of the pull rod 22 near the plunger 11 and extends in a direction perpendicular to the axial direction of the pull rod 22.

[0055] Specifically, the first segment 31 is annular in shape, with a through hole in the middle. One end of the plunger 11 passes through the through hole and connects to the pull rod 22. The first segment 31 is located at the end of the pull rod 22 near the plunger 11, extending in a direction perpendicular to the axial direction of the pull rod 22 and covering the end of the pull rod 22. The inner diameter of the through hole of the first segment 31 is adapted to the outer diameter of one end of the plunger 11. By means of interference fit or by setting a sealing ring, the first segment 31 is fitted onto the end of the plunger 11, so that the first segment 31 can fit tightly against the end face of the pull rod 22, while effectively preventing liquids such as the working medium from leaking along the axial direction of the plunger 11 to the pull rod 22.

[0056] The second segment 32 is connected to the first segment 31, and the second segment 32 extends along the axial direction of the tie rod 22.

[0057] Specifically, the second segment 32 is a cylindrical structure, and its outer wall fits tightly against the inner wall protruding from one side of the pull rod 22. One end of the second segment 32 is connected to the first segment 31, and the second segment 32 extends a certain length along the axial direction of the pull rod 22 towards the plunger 11. The second segment 32 can further guide and restrict the direction of liquid flow, preventing liquid from leaking laterally from the connection between the pull rod 22 and the first segment 31, thus enhancing the reliability of the seal.

[0058] The third segment 33 is connected to the second segment 32, and the third segment 33 extends in a direction perpendicular to the axis of the tie rod 22.

[0059] Specifically, the third segment 33 is also annular, with an inner diameter larger than the outer diameter of the plunger 11. One end of the third segment 33 connects to the end of the second segment 32 furthest from the first segment 31. The third segment 33 extends in a direction perpendicular to the axial direction of the pull rod 22, meaning it is parallel to the first segment 31. A gap exists between the third segment 33 and the plunger 11, ensuring smooth reciprocating motion of the plunger 11 while effectively preventing external impurities from entering the connection point. It also further blocks liquid leakage from the first two segments, creating a multi-stage sealing effect.

[0060] In one embodiment, the first segment 31 extends in a direction perpendicular to the axial direction of the pull rod 22, and its length is greater than the diameter of the plunger 11.

[0061] Specifically, the first segment 31 extends in a direction perpendicular to the axial direction of the pull rod 22, with a length greater than the diameter of the plunger 11, so that the first segment 31 has a large coverage area in the direction perpendicular to the axial direction of the pull rod 22, which can block the medium leaking from the direction of the plunger 11.

[0062] In one embodiment, the second segment 32 extends along the axial length of the pull rod 22, covering the connection area between the plunger 11 and the pull rod 22.

[0063] Specifically, the second section 32 extends along the axial direction of the tie rod 22, covering the connection area between the plunger 11 and the tie rod 22, ensuring that the second section 32 always plays a sealing and guiding role during the connection process between the tie rod 22 and the plunger 11, effectively preventing media leakage.

[0064] In one embodiment, the angle between the second segment 32 and the first segment 31 is a right angle, and the connection between the third segment 33 and the second segment 32 is chamfered.

[0065] Specifically, the right-angle structure between the second segment 32 and the first segment 31 ensures stable force transmission, allowing the first segment 31 and the second segment 32 to be evenly stressed when bearing pressure, avoiding stress concentration due to angular deviation, and ensuring sealing effect and structural strength.

[0066] The connection between the third segment 33 and the second segment 32 is chamfered. The chamfer can be an acute angle, typically 45 degrees. The chamfer reduces stress concentration, improves connection strength, and also guides the medium adhering to the connection between the second segment 32 and the third segment 33, guiding the flow of the medium, reducing medium accumulation, and lowering the risk of leakage.

[0067] In one embodiment, the third segment 33 extends in a direction perpendicular to the axial direction of the tie rod 22 for a length greater than the diameter of the tie rod 22.

[0068] Specifically, the third segment 33 extends in a direction perpendicular to the axis of the tie rod 22, with a length greater than the diameter of the tie rod 22. This allows the third segment 33 to completely cover the outer circumference of the tie rod 22, enhancing the protection against media leakage. At the same time, it can prevent other impurities from entering the hydraulic end assembly 10 in the reverse direction, thus providing dual protection.

[0069] In one embodiment, the pull rod 22 protrudes outward from the side away from its axis, and the third segment 33 covers the protrusion, with an annular sealing ring provided at the contact portion between the third segment 33 and the protrusion.

[0070] Specifically, the pull rod 22 protrudes outward from its axis, and the third segment 33 extends in a direction perpendicular to the axial direction of the pull rod 22, with its outer wall covering one end of the protrusion. An annular sealing ring is provided at the contact point between the third segment 33 and the protrusion. The sealing ring is made of an oil-resistant and corrosion-resistant rubber material, such as nitrile rubber. The annular sealing ring fills the gap between the third segment 33 and the protrusion, improving sealing performance.

[0071] Combination Figure 2 As shown, Figure 2 This is a partial structural diagram of a reciprocating plunger pump provided in one embodiment of this application. In some embodiments, the auxiliary seal 30 and the pull rod 22 are integrally formed, and the auxiliary seal 30 is formed by extending outward along the axial direction from the side of the pull rod 22 away from its axis.

[0072] Specifically, the auxiliary seal 30 extends axially outward from the side of the tie rod 22 away from its axis to form a mudguard structure. The auxiliary seal 30 and the tie rod 22 are integrally formed by casting or forging, improving the overall structural strength and sealing performance. The integrally formed structure avoids problems such as poor sealing and loose connections that may occur in traditional assembled structures, and can better adapt to the working environment of reciprocating plunger pumps under high pressure and high frequency reciprocating motion, thus extending the service life of the equipment.

[0073] Combination Figure 1 As shown, Figure 1 This is a partial structural schematic diagram of a reciprocating plunger pump provided in one embodiment of this application. In some embodiments, the tie rod oil seal assembly 23 includes a tie rod oil seal seat 231, a tie rod oil seal 232, and a tie rod oil seal baffle 233. The tie rod oil seal seat 231 is fixed to the housing of the power end assembly 20, and the tie rod oil seal baffle 233 is slidably connected to the tie rod oil seal seat 231.

[0074] Specifically, the pull rod oil seal seat 231 is bolted to the housing of the power end assembly 20, and its inner hole has a stepped sealing groove. The pull rod oil seal 232 is a double-lip seal; its inner lip is interference-fitted with the pull rod 22, and its outer lip is clearance-fitted with the sealing groove to prevent media leakage or the entry of external impurities. The pull rod oil seal baffle 233 is slidably connected to the pull rod oil seal seat 231 through a dovetail groove structure. The outer surface of the pull rod 22 is hard anodized to reduce wear on the pull rod oil seal 232.

[0075] 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.

[0076] The above embodiments merely illustrate 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 reciprocating plunger pump, comprising a hydraulic end assembly (10) and a power end assembly (20), characterized in that, Also includes: The hydraulic end assembly (10) includes a plunger (11) and a packing (12) that seals the plunger (11); The power end assembly (20) includes a crosshead (21), a pull rod (22) and a pull rod oil seal assembly (23). One end of the pull rod (22) is connected to the crosshead (21), and the other end is connected to the plunger (11). An auxiliary seal (30) is provided at the connection between the housing of the hydraulic end assembly (10) and the housing of the power end assembly (20). The outer diameter of the auxiliary seal (30) is larger than the outer diameter of the plunger (11) and the pull rod (22). There is an axial gap between the auxiliary seal (30) and the packing (12).

2. The reciprocating plunger pump according to claim 1, characterized in that, The auxiliary seal (30) is fixed between the plunger (11) and the pull rod (22), and the auxiliary seal (30) is sleeved on the end where the plunger (11) and the pull rod (22) are connected.

3. The reciprocating plunger pump according to claim 2, characterized in that, The auxiliary seal (30) includes a first section (31), a second section (32) and a third section (33). The first section (31) is located at one end of the pull rod (22) near the plunger (11) and extends in a direction perpendicular to the axial direction of the pull rod (22). The second section (32) is connected to the first section (31) and extends in the axial direction of the pull rod (22). The third section (33) is connected to the second section (32) and extends in a direction perpendicular to the axial direction of the pull rod (22).

4. The reciprocating plunger pump according to claim 3, characterized in that, The first segment (31) extends in a direction perpendicular to the axial direction of the pull rod (22) for a length greater than the diameter of the plunger (11).

5. The reciprocating plunger pump according to claim 3, characterized in that, The second segment (32) extends along the axial length of the pull rod (22) and covers the connection area between the plunger (11) and the pull rod (22).

6. The reciprocating plunger pump according to claim 5, characterized in that, The angle between the second segment (32) and the first segment (31) is a right angle, and there is a gap between the second segment (32) and the plunger (11).

7. The reciprocating plunger pump according to claim 3, characterized in that, The third segment (33) extends in a direction perpendicular to the axial direction of the pull rod (22) for a length greater than the diameter of the pull rod (22).

8. The reciprocating plunger pump according to claim 3, characterized in that, The pull rod (22) protrudes outward from the side away from its axis, and the third section (33) covers the protrusion. The part of the third section (33) that contacts the protrusion is provided with an annular sealing ring.

9. The reciprocating plunger pump according to claim 2, characterized in that, The auxiliary seal (30) and the pull rod (22) are integrally formed. The auxiliary seal (30) is formed by extending outward along the axial direction of the pull rod (22) from the side away from its axis.

10. The reciprocating piston pump according to any one of claims 1-9, characterized in that, The pull rod oil seal assembly (23) includes a pull rod oil seal seat (231), a pull rod oil seal (232), and a pull rod oil seal baffle (233); the pull rod oil seal seat (231) is fixed on the housing of the power end assembly (20), and the pull rod oil seal baffle (233) is slidably connected to the pull rod oil seal seat (231).

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