Fluid end of plunger pump, and plunger pump

Abstract

The present application relates to the field of oil and gas equipment. Disclosed are a fluid end of a plunger pump, and a plunger pump. The fluid end comprises a valve block, a plunger, a first valve assembly, a second valve assembly and a plugging assembly, wherein the valve block is provided with a valve chamber, a plunger channel, a fluid inlet, a fluid outlet and a valve bore, the plunger channel being in communication with the valve chamber, the valve bore being in communication with the valve chamber and arranged opposite the plunger channel in a first direction, the fluid inlet and the fluid outlet being both in communication with the valve chamber, and the fluid inlet and the fluid outlet being arranged opposite each other in a second direction; the plunger is movably arranged in the plunger channel, the first valve assembly is arranged at the fluid inlet, the second valve assembly is arranged at the fluid outlet, and the plugging assembly is arranged at the valve bore; the plugging assembly comprises a retainer cap, and an outer peripheral surface of the retainer cap is provided with an external thread structure that has a fillet radius at the thread root ranging from R0.6 mm to R1.5 mm; and the wall of the valve bore is provided with an internal thread structure that fits with the external thread structure.

Description

Hydraulic end of plunger pump and plunger pump

[0001] Cross-references

[0002] This application claims priority to Chinese Patent Application No. 202423217834.6, filed on December 25, 2024, entitled "Hydraulic End of Plunger Pump and Plunger Pump", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application belongs to the field of oil and gas equipment technology, specifically relating to the hydraulic end of a plunger pump and the plunger pump itself. Background Technology

[0004] Hydraulic fracturing has gradually become a major production enhancement measure in oilfields. Under high pressure, fracturing fluid or proppant-carrying fluid is pumped to the bottom of the well to achieve fracturing operations, thereby increasing oil and gas production. A key component of this method is the plunger pump, which generates high pressure and mainly consists of a power end and a hydraulic end.

[0005] With the changing global energy supply structure, unconventional energy sources such as shale gas and tight oil are playing an increasingly important role, thus placing higher demands on fracturing operations. The large-scale exploitation of unconventional energy sources leads to higher pressures and longer operation times in fracturing operations, which accelerates the damage to plunger pumps, especially the hydraulic end, a core component of the plunger pump.

[0006] During operation, the plunger reciprocates, pressurizing the internal medium by opening and closing the upper and lower valves. The suction cap is subjected to alternating loads during operation; each plunger reciprocation stretches the thread root. Over prolonged operation, fatigue cracks may occur at the thread root of the suction cap. Once the suction cap thread breaks, it no longer bears the load, and the force borne by the cap during operation shifts to the outer threads. Under alternating loads, the outer threads of the valve box may crack due to the pressure from the cap. Summary of the Invention

[0007] The purpose of this application is to provide a hydraulic end of a plunger pump and a plunger pump.

[0008] This application provides a hydraulic end of a plunger pump, comprising: a valve box, a plunger, a first valve assembly, a second valve assembly, and a plugging assembly; the valve box has a valve cavity, a plunger channel, an inlet, a outlet, and a valve orifice; the plunger channel communicates with the valve cavity, and the valve orifice communicates with the valve cavity and is disposed opposite to the plunger channel in a first direction; the inlet and outlet are respectively communicated with the valve cavity, and the inlet and outlet are disposed opposite to each other in a second direction, the first direction being perpendicular to the second direction; the plunger is movably disposed in the plunger channel; the first valve assembly is disposed at the inlet; the second valve assembly is disposed at the outlet; and the plugging assembly is disposed at the valve orifice; the plugging assembly includes a pressure cap, the outer circumferential surface of which has an external thread structure, the radius of the root of the thread of the external thread structure being R0.6mm~R1.5mm; the valve orifice has an internal thread structure on its wall, the internal thread structure engaging with the external thread structure.

[0009] This application also provides a plunger pump, including the hydraulic end described above. Attached Figure Description

[0010] Figure 1 is a cross-sectional schematic diagram of the hydraulic end disclosed in the embodiment of this application;

[0011] Figure 2 is a partial cross-sectional view of the connection between the valve box and the sealing assembly disclosed in an embodiment of this application;

[0012] Figure 3 is a partial schematic diagram of the external thread structure of the pressure cap disclosed in the embodiment of this application;

[0013] Figure 4 is a cross-sectional schematic diagram of the split hydraulic end disclosed in the embodiment of this application.

[0014] Explanation of reference numerals in the attached drawings: 10-valve box; 10a-box body; 10b-fixed seat; 11-valve cavity; 12-plunger channel; 13-inlet; 14-outlet; 15-valve hole; 15a-first hole section; 15b-second hole section; 15c-first hole; 15d-second hole; 16-fastener; 20-plunger; 30-first valve assembly; 40-second valve assembly; 50-sealing assembly; 51-pressure cap; 511-thread; 5111-first inclined surface; 5112-second inclined surface; 512-arc structure; M-first plane; 52-pressure cap; 60-sealant. Detailed Implementation

[0015] 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, 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.

[0016] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0017] The embodiments of this application will be described in detail below with reference to the accompanying drawings and specific examples and application scenarios.

[0018] Referring to Figures 1 to 4, this application discloses a hydraulic end of a plunger pump, which includes a valve box 10, a plunger 20, a first valve assembly 30, a second valve assembly 40, and a sealing assembly 50.

[0019] The valve box 10 is a basic component that provides an installation base for the plunger 20, the first valve assembly 30, the second valve assembly 40, and the plugging assembly 50. As shown in Figures 1, 2, and 4, the valve box 10 may include a valve chamber 11, a plunger channel 12, an inlet 13, an outlet 14, and a valve orifice 15. The valve chamber 11 contains fracturing fluid. The plunger channel 12 communicates with the valve chamber 11, and the plunger 20 is movably disposed within the plunger channel 12. Thus, the reciprocating movement of the plunger 20 within the plunger channel 12 allows for periodic pressurization and release of the fracturing fluid in the valve chamber 11. The inlet 13 communicates with the valve... The valve chamber 11 is connected, and the first valve assembly 30 is located at the inlet 13. In this way, the fracturing fluid from the outside can be forced open by the first valve assembly 30 and enter the valve chamber 11 through the inlet 13. The outlet 14 is connected to the valve chamber 11, and the second valve assembly 40 is located at the outlet 14. In this way, the fracturing fluid in the valve chamber 11 can be forced open by the second valve assembly 40 under the squeezing action of the plunger 20 and flow out through the outlet 14, so as to supply fracturing fluid to the downstream.

[0020] The inlet 13 and outlet 14 can be arranged opposite each other in the second direction, which can make the fracturing fluid flow into and out of the valve box 10 more smoothly and effectively prevent the local inner wall of the valve box 10 from generating large flow resistance to the fracturing fluid.

[0021] In addition, the specific structure and working principle of the first valve component 30 and the second valve component 40 can be referred to the relevant technology, and will not be elaborated here.

[0022] The valve orifice 15 is connected to the valve cavity 11 and is disposed opposite to the plunger channel 12 in a first direction, wherein the first direction is perpendicular to the second direction. The sealing component 50 is disposed at the valve orifice 15, so that the sealing component 50 can seal the valve orifice 15 to prevent the leakage of fracturing fluid in the valve cavity 11.

[0023] The sealing assembly 50 may include a pressure cap 51. The outer circumferential surface of the pressure cap 51 may be provided with an external thread structure. Correspondingly, the hole wall of the valve hole 15 may be provided with an internal thread structure, and the internal thread structure and the external thread structure are connected in a mating manner. In this way, a detachable connection between the pressure cap 51 and the valve box 10 can be realized, so as to facilitate the maintenance of the inside of the valve box 10. Of course, it can also facilitate the disassembly and assembly of the internal components of the valve box 10.

[0024] Furthermore, the radius of the fillet at the root of the thread 511 in the external thread structure can be R0.6mm to R1.5mm, including, for example, R0.6mm, R0.8mm, R1.0mm, R1.2mm, R1.4mm, R1.5mm, etc. Of course, other values ​​are also possible, which are not specifically limited here.

[0025] In this embodiment, by improving the external thread structure of the pressure cap 51, the radius of the fillet at the root of the thread 511 is R0.6mm to R1.5mm, thereby improving the deformation resistance of the thread 511, alleviating the stress concentration problem at the root of the thread 511, and improving the overall strength of the thread 511 to a certain extent. Thus, during the reciprocating operation of the plunger 20, even if the pressure cap 51 is subjected to alternating loads, causing the thread 511 to be periodically stretched, the improved overall strength of the thread 511 ensures that the external thread structure of the pressure cap 51 will not fatigue crack under pressure during operation, further ensuring a stable and reliable connection between the pressure cap 51 and the valve box 10.

[0026] Referring to Figure 3, in some embodiments, the external thread structure with a length of 1 inch may include three complete threads 511. That is, within a length of 25.4 mm, the external thread structure includes three complete threads 511. Compared with other methods of using threads 511 in related technologies, the embodiments of this application can effectively reduce the number of threads 511 per unit length (i.e., 1 inch), which can improve the strength of each thread 511 to a certain extent and increase the deformation resistance of each thread 511, thereby further improving the reliability of the installation between the pressure cap 51 and the valve box 10.

[0027] Referring again to Figure 3, in some embodiments, each thread 511 may include a first inclined surface 5111 and a second inclined surface 5112. The first inclined surface 5111 is located on the side of the second inclined surface 5112 closer to the valve cavity 11. The first inclined surface 5111 and the second inclined surface 5112 of each thread 511 are located on opposite sides of the first plane M. The angle between the first inclined surface 5111 and the first plane M is 45°, and the angle between the second inclined surface 5112 and the first plane M is 7°. The first plane M is perpendicular to the axis of the valve hole 15.

[0028] Based on the above configuration, during the reciprocating motion of the plunger 20, the fracturing fluid in the squeeze valve chamber 11 will exert a large squeezing effect on the sealing assembly 50, thereby subjecting the pressure cap 51 to a large impact force. Thus, in this embodiment, the second inclined surface 5112 can be adapted to the internal thread structure of the valve hole 15, which can help improve the load-bearing capacity of the pressure cap 51 and prevent the pressure cap 51 from being damaged by the squeezing effect of the fracturing action.

[0029] Of course, in other embodiments, the tilt angles of the first tilted surface 5111 and the second tilted surface 5112 can be other angles, which are not specifically limited here.

[0030] Referring to Figures 2 and 3, in some embodiments, an arc-shaped structure 512 may be provided between two adjacent threads 511. Furthermore, the first inclined surface 5111 of the thread 511 closer to the valve cavity 11 and the second inclined surface 5112 of the thread 511 farther from the valve cavity 11 can be transitionally connected through the arc-shaped structure 512. Based on this arrangement, an arc-shaped transition can be achieved between two adjacent threads 511. Compared to a sharp-corner approach, the arc-shaped structure 512 in this embodiment effectively reduces stress concentration between two adjacent threads 511.

[0031] Optionally, at least a portion of the arc-shaped structure 512 can be a circular arc structure with a radius ranging from 0.6mm to 1.5mm, such as 0.6mm, 0.8mm, 1.0mm, 1.2mm, 1.4mm, 1.5mm, etc. Of course, other values ​​are also possible, which are not specifically limited here.

[0032] Based on the above settings, the embodiments of this application can effectively alleviate the problem of stress concentration and premature cracking between two adjacent threads 511.

[0033] In some embodiments, the sealing assembly 50 may further include a pressure cap 52 disposed in the valve orifice 15 and located between the pressure cap 51 and the valve cavity 11. Thus, the pressure cap 52 can seal the valve orifice 15, and the pressure cap 51 can limit the pressure cap 52. The cooperation between the pressure cap 52 and the pressure cap 51 can achieve a tight seal on the valve orifice 15 to prevent leakage of fracturing fluid in the event of excessive pressure in the valve cavity 11.

[0034] Further, as shown in Figures 1 and 2, the valve orifice 15 may include a first orifice section 15a and a second orifice section 15b. The second orifice section 15b communicates with the valve cavity 11 through the first orifice section 15a. The pressure cap 52 is disposed in the first orifice section 15a, and the pressure cap 51 is threadedly connected to the second orifice section 15b. Based on this arrangement, the fit between the pressure cap 52 and the inner wall of the first orifice section 15a ensures the sealing of the first orifice section 15a, effectively preventing leakage of the fracturing fluid. The fit between the pressure cap 51 and the second orifice section 15b allows the pressure cap 51 to exert a squeezing effect on the pressure cap 52, and also seals the second orifice section 15b through the fit between the pressure cap 51 and the second orifice section 15b.

[0035] Optionally, as shown in Figure 2, the diameter D3 of the plunger 20 is smaller than the diameter D2 of the first orifice 15a, and the diameter D2 of the first orifice 15a is smaller than the diameter D1 of the second orifice 15b. Based on this arrangement, when the pressure of the fracturing fluid in the valve chamber 11 is constant, the smaller the cross-sectional area of ​​the plunger 20 and the cross-sectional area of ​​the first orifice 15a, the smaller the pressure of the fracturing fluid on the cap 52, and the smaller the force on the cap 51, which is beneficial to improving the service life of the external thread of the cap 51. Therefore, this embodiment controls the reduction of the suction orifice size by making D3 < D2 < D1, thereby reducing the force on the external thread structure of the cap 52.

[0036] In some embodiments, as shown in Figure 4, the valve box 10 may include a box body 10a and a fixing seat 10b, with the fixing seat 10b detachably connected to the box body 10a. It should be noted that this method alters the structure of the valve box 10. Even if fatigue cracking occurs in the external thread structure of the pressure cap 51, it will not extend to the box body 10a; only the fixing seat 10b needs to be replaced, thus effectively protecting the box body 10a and reducing costs. Optionally, the fixing seat 10b can be connected to the box body 10a by screwing, snap-fitting, or plugging for easy assembly and disassembly.

[0037] The valve hole 15 may include a first hole 15c and a second hole 15d. The first hole 15c is located in the housing body 10a, and the second hole 15d is located in the fixing seat 10b. The second hole 15d communicates with the valve cavity 11 through the first hole 15c. Furthermore, a pressure cap 52 is located in the first hole 15c, and a pressure nut 51 is threadedly connected to the second hole 15d. Based on this, the fit between the pressure cap 52 and the inner wall of the first hole 15c ensures a tight seal at the first hole 15c, effectively preventing leakage of the fracturing fluid. The fit between the pressure nut 51 and the second hole 15d allows the pressure nut 51 to compress the pressure cap 52, and also seals the second hole 15d.

[0038] Optionally, the diameter D3 of the plunger 20 is smaller than the diameter D2 of the first hole 15c, and the diameter D2 of the first hole 15c is smaller than the diameter D1 of the second hole 15d. Based on this arrangement, when the pressure of the fracturing fluid in the valve cavity 11 is constant, the smaller the cross-sectional area of ​​the plunger 20 and the cross-sectional area of ​​the first hole 15c, the smaller the pressure of the fracturing fluid on the cap 52, and the smaller the force on the cap 51, which is beneficial to improving the service life of the external thread of the cap 51. Therefore, this embodiment controls the reduction of the suction orifice size by making D3 < D2 < D1, thereby reducing the force on the external thread structure of the cap 52.

[0039] In some more specific embodiments, the housing body 10a may have a first mounting hole (not shown in the figure), and the fixing seat 10b may have a second mounting hole (not shown in the figure). The fixing seat 10b is located on the side of the housing body 10a, and the second mounting hole is opposite to the first mounting hole. Additionally, the valve box 10 may also include a fastener 16, which passes through the first mounting hole and the second mounting hole to secure the fixing seat 10b to the side of the housing body 10a. Exemplarily, the first mounting hole may be a threaded hole, the second mounting hole may be an unthreaded hole, and the fastener 16 may be a bolt, screw, or similar fastener.

[0040] Of course, in other embodiments, the fixed base 10b and the box body 10a can also be fixedly connected, such as by welding or riveting, to ensure the reliability of the connection.

[0041] To further improve sealing, the hydraulic end may also include a seal 60, which is disposed between at least a portion of the plugging assembly 50 and the valve port 15 to seal the connection between the plugging assembly 50 and the valve port 15. Based on this arrangement, the sealing performance between the plugging assembly 50 and the valve port 15 can be improved by providing the seal 60, effectively preventing leakage of fracturing fluid. For example, the seal 60 may be a sealing ring.

[0042] Optionally, the seal 60 can be disposed between the gland 52 and the first hole section 15a or the first hole 15c of the valve hole 15; it can also be disposed between the cap 51 and the second hole section 15b or the second hole 15d of the valve hole 15; or it can be disposed simultaneously between the gland 52 and the first hole section 15a or the first hole 15c of the valve hole 15, and between the cap 51 and the second hole section 15b or the second hole 15d of the valve hole 15, as long as the fracturing fluid does not leak, the specific method is not limited.

[0043] Based on the hydraulic end of the aforementioned plunger pump, this application also discloses a plunger pump. The disclosed plunger pump includes the aforementioned hydraulic end. In addition, the plunger pump may also include a drive unit to drive the hydraulic end to rotate. It should be noted that the specific structure and working principle of the plunger pump can be found in related technologies and will not be elaborated upon here.

[0044] In summary, the embodiments of this application optimize the hydraulic end, specifically by reducing the size of the suction orifice by ensuring that D3 < D2 < D1. This results in a smaller force on the external thread structure of the pressure cap 51 under a constant pressure within the valve chamber 11, which is beneficial for improving the service life of the external thread structure. Furthermore, the use of the arc-shaped structure 512 reduces stress concentration at the root of the thread 511, improving the strength and deformation resistance of the thread 511. Therefore, the embodiments of this application effectively solve the problem of fatigue cracking of the external thread structure of the pressure cap 51 in the hydraulic end after prolonged use, extending the service life of the plunger pump, reducing maintenance costs, and improving operational efficiency.

[0045] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A hydraulic end of a plunger pump, the hydraulic end comprising: Valve box (10), plunger (20), first valve assembly (30), second valve assembly (40) and plugging assembly (50); The valve box (10) is provided with a valve chamber (11), a plunger channel (12), an inlet (13), a outlet (14), and a valve hole (15). The plunger channel (12) is connected to the valve chamber (11), and the valve hole (15) is connected to the valve chamber (11) and is arranged opposite to the plunger channel (12) in a first direction. The inlet (13) and the outlet (14) are respectively connected to the valve chamber (11), and the inlet (13) and the outlet (14) are arranged opposite to each other in a second direction. The first direction is perpendicular to the second direction. The plunger (20) is movably disposed in the plunger channel (12), the first valve assembly (30) is disposed at the inlet (13), the second valve assembly (40) is disposed at the outlet (14), and the sealing assembly (50) is disposed at the valve hole (15). The sealing assembly (50) includes a pressure cap (51), the outer peripheral surface of which is provided with an external thread structure, and the radius of the fillet at the root of the thread (511) of the external thread structure is R0.6mm to R1.5mm. The valve hole (15) has an internal thread structure on its hole wall, and the internal thread structure is connected to the external thread structure.

2. The hydraulic end according to claim 1, wherein, The external thread structure, which is 1 inch in length, includes three complete threads (511).

3. The hydraulic end according to claim 2, wherein, Each of the threads (511) includes a first inclined surface (5111) and a second inclined surface (5112), wherein the first inclined surface (5111) is located on the side of the second inclined surface (5112) closer to the valve cavity (11); The first inclined surface (5111) and the second inclined surface (5112) of each thread (511) are located on opposite sides of the first plane (M), the angle between the first inclined surface (5111) and the first plane (M) is 45°, the angle between the second inclined surface (5112) and the first plane (M) is 7°, wherein the first plane (M) is perpendicular to the axis of the valve hole (15).

4. The hydraulic end according to claim 3, wherein, An arc-shaped structure (512) is provided between two adjacent threads (511); In two adjacent threads (511), the first inclined surface (5111) of the thread (511) closer to the valve cavity (11) and the second inclined surface (5112) of the thread (511) farther from the valve cavity (11) are connected by the arc-shaped structure (512).

5. The hydraulic end according to claim 4, wherein, At least a portion of the arc-shaped structure (512) is a circular arc structure, and the radius of the circular arc structure ranges from 0.6 mm to 1.5 mm.

6. The hydraulic end according to claim 1, wherein, The valve orifice (15) includes a first orifice section (15a) and a second orifice section (15b), and the second orifice section (15b) communicates with the valve cavity (11) through the first orifice section (15a); The sealing assembly (50) further includes a pressure cap (52), which is disposed in the first hole section (15a), and the pressure cap (51) is threadedly connected to the second hole section (15b); The diameter of the plunger (20) is smaller than the diameter of the first orifice (15a), and the diameter of the first orifice (15a) is smaller than the diameter of the second orifice (15b).

7. The hydraulic end according to claim 1, wherein, The valve box (10) includes a box body (10a) and a fixing seat (10b), and the fixing seat (10b) is detachably connected to the box body (10a); The valve hole (15) includes a first hole (15c) and a second hole (15d). The first hole (15c) is opened in the box body (10a), and the second hole (15d) is opened in the fixed seat (10b). The second hole (15d) communicates with the valve cavity (11) through the first hole (15c). The sealing assembly (50) further includes a pressure cap (52), which is disposed in the first hole (15c), and the pressure cap (51) is threadedly connected to the second hole (15d); The diameter of the plunger (20) is smaller than the diameter of the first hole (15c), and the diameter of the first hole (15c) is smaller than the diameter of the second hole (15d).

8. The hydraulic end according to claim 7, wherein, The box body (10a) is provided with a first mounting hole, and the fixing seat (10b) is provided with a second mounting hole. The fixing seat (10b) is located on the side of the box body (10a), and the second mounting hole is arranged opposite to the first mounting hole. The valve box (10) also includes a fastener (16) which passes through the first mounting hole and the second mounting hole to fasten the fixing seat (10b) to the side of the box body (10a).

9. The hydraulic end according to claim 1, wherein, The hydraulic end also includes a seal (60) disposed between at least a portion of the plugging assembly (50) and the valve port (15) to seal the connection between the plugging assembly (50) and the valve port (15).

10. A plunger pump comprising the hydraulic end as described in any one of claims 1 to 9.

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