Fluid end of plunger pump and plunger pump

Abstract

The utility model discloses a fluid end of a plunger pump and the plunger pump, and relates to the field of oil and gas equipment. The hydraulic end comprises a valve box, a plunger, a first valve assembly, a second valve assembly and a plugging assembly. The valve box is provided with a valve cavity, a plunger channel, a liquid inlet, a liquid outlet and a valve hole, the plunger channel communicates with the valve cavity, the valve hole communicates with the valve cavity and is opposite to the plunger channel in the first direction, the liquid inlet and the liquid outlet communicate with the valve cavity, and the liquid inlet and the liquid outlet are opposite to each other in the second direction; the plunger is movably arranged in the plunger channel, the first valve assembly is arranged at the liquid inlet, the second valve assembly is arranged at the liquid outlet, and the plugging assembly is arranged at the valve hole; the plugging assembly comprises a pressing cap, an external thread structure is arranged on the peripheral face of the pressing cap, and the fillet range of the thread root of the external thread structure ranges from R0.6 mm to R1.5 mm. An internal thread structure is arranged on the hole wall of the valve hole and connected with the external thread structure in a matched mode. The problem that the root of the thread tooth of the suction pressing cap is prone to fatigue cracking is solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil and gas equipment, and particularly relates to a hydraulic end of a plunger pump and the plunger pump. BACKGROUND

[0002] Hydraulic fracturing construction gradually becomes a main stimulation measure of oil fields, and under the action of high pressure, fracturing fluid or sand-carrying fluid is pumped to the bottom of a well to realize fracturing operation, thereby increasing oil and gas production. The key component of the construction mode is a plunger pump generating high pressure, which mainly consists of a power end and a hydraulic end.

[0003] With the change of global energy supply structure, unconventional energy such as shale gas and tight oil gradually plays an increasingly important role, and therefore higher requirements are put forward for the fracturing construction mode. With the large-scale exploitation of unconventional energy, the pressure of fracturing operation is higher, and the operation time is longer, which will accelerate the damage of the plunger pump, especially the hydraulic end as the core component of the plunger pump.

[0004] During the work of the hydraulic end, the plunger reciprocates to realize pressure increase of the internal medium through the opening and closing of the upper and lower valve bodies. The suction pressure cap bears alternating load during the operation, and the thread root is stretched once per reciprocation of the plunger. During the long-time operation, the thread root of the suction pressure cap will appear fatigue cracking. After the thread of the suction pressure cap is broken, the broken thread no longer bears load, and the force borne by the pressure cap during the operation will be transferred to the outside thread of the pressure cap. Under alternating load, the outside thread of the valve box will be cracked by the pressure cap. CONTENT OF THE INVENTION

[0005] The purpose of the embodiment of the application is to provide a hydraulic end of a plunger pump and the plunger pump, which can solve the problem that the thread root of the suction pressure cap is prone to fatigue cracking.

[0006] In order to solve the above technical problem, the application is implemented as follows:

[0007] The embodiment of the application provides a hydraulic end of a plunger pump, which comprises a valve box, a plunger, a first valve assembly, a second valve assembly and a blocking assembly.

[0008] The valve box is provided with a valve cavity, a plunger channel, a liquid inlet, a liquid outlet and a valve hole, the plunger channel is communicated with the valve cavity, the valve hole is communicated with the valve cavity and oppositely arranged with the plunger channel in a first direction, the liquid inlet and the liquid outlet are respectively communicated with the valve cavity, and the liquid inlet and the liquid outlet are oppositely arranged in a second direction, and the first direction is perpendicular to the second direction.

[0009] The plunger is movably arranged in the plunger channel, the first valve element is arranged at the liquid inlet, the second valve element is arranged at the liquid outlet, and the sealing element is arranged at the valve hole;

[0010] The sealing element comprises a pressure cap, and an outer thread structure is arranged on the outer circumferential surface of the pressure cap.

[0011] The hole wall of the valve hole is provided with an inner thread structure, and the inner thread structure is connected with the outer thread structure in a matched mode.

[0012] The embodiment of the present application further provides a plunger pump comprising the above-mentioned fluid end.

[0013] In the embodiment of the present application, the outer thread structure of the pressure cap is improved, and the round angle range of the thread root of the outer thread structure is R0.6mm-R1.5mm, so that the deformation resistance of the thread can be improved, the stress concentration problem of the thread root can be relieved, the overall strength of the thread is improved to a certain extent, and thus, even if the pressure cap is subjected to alternating loads during the reciprocating operation of the plunger, the thread is periodically stretched, but due to the improved overall strength of the thread, the outer thread structure of the pressure cap can be prevented from being fatigued and cracked under the pressure of the pressure cap during operation, and the stable and reliable connection between the pressure cap and the valve box is further ensured. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A cross-sectional view of the fluid end disclosed in the embodiment of the present application is shown;

[0015] Figure 2 A local cross-sectional view of the connection between the valve box and the sealing element disclosed in the embodiment of the present application is shown;

[0016] Figure 3 A local view of the outer thread structure of the pressure cap disclosed in the embodiment of the present application is shown;

[0017] Figure 4 A cross-sectional view of the split type fluid end disclosed in the embodiment of the present application is shown.

[0018] MARK DESCRIPTION:

[0019] 10-valve box; 10a-box body; 10b-fixed seat; 11-valve cavity; 12-plunger channel; 13-liquid inlet; 14-liquid outlet; 15-valve hole; 15a-first hole section; 15b-second hole section; 15c-first hole; 15d-second hole; 16-fastener;

[0020] 20-plunger;

[0021] 30-first valve element;

[0022] 40 - second valve assembly;

[0023] 50 - blocking assembly; 51 - pressure cap; 511 - screw thread; 5111 - first inclined surface; 5112 - second inclined surface; 512 - arc structure; M - first plane; 52 - gland;

[0024] 60 - seal. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0026] The terms "first", "second", and the like in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be exchanged under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally a category, and are not limited to the number of objects, for example, the first object can be one or more. In addition, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / ", generally indicates that the front and rear associated objects are in an "or" relationship.

[0027] The embodiments of the present application will be described in detail below with reference to the drawings and specific examples and their application scenarios.

[0028] Reference Figures 1 to 4 The embodiments of the present application disclose a hydraulic end of a plunger pump. The disclosed hydraulic end comprises a valve box 10, a plunger 20, a first valve assembly 30, a second valve assembly 40, and a blocking assembly 50.

[0029] The valve box 10 is a basic component, which can provide a mounting base for the plunger 20, the first valve assembly 30, the second valve assembly 40, and the blocking assembly 50, etc. Among them, for example, Figure 1 , Figure 2 and Figure 4As shown, the valve box 10 can be provided with a valve cavity 11, a plunger channel 12, a liquid inlet 13, a liquid outlet 14 and a valve hole 15; the valve cavity 11 can be used to contain fracturing liquid, the plunger channel 12 is in communication with the valve cavity 11, and the plunger 20 is movably arranged in the plunger channel 12, so that the fracturing liquid in the valve cavity 11 can be periodically pressurized and released by the reciprocating movement of the plunger 20 in the plunger channel 12; the liquid inlet 13 is in communication with the valve cavity 11, and the first valve assembly 30 is arranged at the liquid inlet 13, so that the external fracturing liquid can flush away the first valve assembly 30 and enter the valve cavity 11 through the liquid inlet 13; the liquid outlet 14 is in communication with the valve cavity 11, and the second valve assembly 40 is arranged at the liquid outlet 14, so that the fracturing liquid in the valve cavity 11 can flush away the second valve assembly 40 under the extrusion of the plunger 20 and flow out through the liquid outlet 14, so as to supply fracturing liquid to the downstream.

[0030] Wherein, the liquid inlet 13 and the liquid outlet 14 can be oppositely arranged in the second direction, so that the fracturing liquid can flow into and out of the valve box 10 more smoothly, effectively preventing the local inner wall of the valve box 10 from causing a large flow resistance to the fracturing liquid.

[0031] In addition, the specific structure of the first valve assembly 30 and the second valve assembly 40 and its working principle can refer to the related technology, which will not be described in detail here.

[0032] The valve hole 15 is in communication with the valve cavity 11 and is oppositely arranged with the plunger channel 12 in the first direction, wherein the first direction is perpendicular to the second direction, and the blocking assembly 50 is arranged at the valve hole 15, so that the valve hole 15 can be blocked by the blocking assembly 50 to prevent the fracturing liquid in the valve cavity 11 from leaking.

[0033] Wherein, the blocking assembly 50 can include a pressure cap 51, and the outer peripheral surface of the pressure cap 51 can be provided with an external thread structure, correspondingly, the hole wall of the valve hole 15 can be provided with an internal thread structure, and the internal thread structure is connected with the external thread structure, so that the 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, the disassembly and assembly of the parts inside the valve box 10 can also be facilitated.

[0034] Further, the round corner range of the root of the thread 511 of the external thread structure can be R0.6mm~R1.5mm, for example, including R0.6mm, R0.8mm, R1.0mm, R1.2mm, R1.4mm, R1.5mm and the like, of course, it can also be other values, which are not limited here.

[0035] In the embodiment of the present application, the outer thread structure of the pressure cap 51 is improved, and the fillet range of the root of the thread 511 is R0.6mm-R1.5mm, so that the deformation resistance of the thread 511 can be improved, the stress concentration problem of the root of the thread 511 is alleviated, and the overall strength of the thread 511 is improved to a certain extent. Therefore, during the reciprocating operation of the plunger 20, even if the pressure cap 51 is subjected to alternating loads, the thread 511 is periodically stretched, but due to the improved overall strength of the thread 511, the outer thread structure of the pressure cap 51 can be prevented from fatigue cracking under pressure during operation, and the stable and reliable connection between the pressure cap 51 and the valve box 10 is further ensured.

[0036] Reference Figure 3 In some embodiments, the outer thread structure with a length of 1 inch can include three complete threads 511, that is, within a length of 25.4mm, the outer thread structure includes three complete threads 511. Compared with the number of threads 511 in the related art, the number of threads 511 per unit length (i.e., 1 inch length) can be effectively reduced, the strength of each thread 511 can be improved to a certain extent, the deformation resistance of each thread 511 can be increased, and the reliability of the installation between the pressure cap 51 and the valve box 10 can be further improved.

[0037] Reference Figure 3 In some embodiments, each thread 511 can 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 close to the valve cavity 11, and the first inclined surface 5111 and the second inclined surface 5112 of each thread 511 are located on the opposite sides of the first plane M, respectively. 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°, and the first plane M is perpendicular to the axis of the valve hole 15.

[0038] Based on the above setting, during the reciprocating movement of the plunger 20, the fracturing fluid in the valve cavity 11 can generate a large extrusion effect on the plugging assembly 50, so that the pressure cap 51 can be subjected to a large impact force. Therefore, the second inclined surface 5112 of the present application can be matched with the inner thread structure of the valve hole 15, so as to improve the carrying capacity of the pressure cap 51 and prevent the thread 511 from being damaged due to the extrusion effect of the fracturing action.

[0039] Of course, in other embodiments, the inclination angles of the first inclined surface 5111 and the second inclined surface 5112 can also be other angles, which are not limited here.

[0040] Reference Figure 2and Figure 3 In some embodiments, an arc-shaped structure 512 can be arranged between two adjacent threads 511, and a first inclined surface 5111 of the thread 511 close to the valve cavity 11 and a second inclined surface 5112 of the thread 511 away from the valve cavity 11 can be connected through the arc-shaped structure 512. Based on this arrangement, the arc-shaped transition between the two adjacent threads 511 can be achieved, and compared with the sharp corner mode, the stress concentration problem between the two adjacent threads 511 can be effectively reduced by arranging the arc-shaped structure 512 in the embodiments of the present application.

[0041] Optionally, at least part of the arc-shaped structure 512 can be a circular arc structure, and the radius of the circular arc structure can range from 0.6 mm to 1.5 mm, for example, including 0.6 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.4 mm, 1.5 mm, and the like. Of course, other values are also possible, which are not limited here.

[0042] Based on the above arrangement, the problem of early cracking due to stress concentration between the two adjacent threads 511 can be effectively alleviated.

[0043] In some embodiments, the plugging assembly 50 can further include a gland 52 arranged in the valve hole 15 and located between the pressure cap 51 and the valve cavity 11. In this way, the valve hole 15 can be plugged by the gland 52, and the gland 52 can be limited by the pressure cap 51, so that the valve hole 15 can be tightly plugged by the cooperation of the gland 52 and the pressure cap 51 to prevent the fracturing fluid from leaking in the case of excessive pressure in the valve cavity 11.

[0044] Further, as shown in Figure 1 and Figure 2 The valve hole 15 can include a first hole section 15a and a second hole section 15b, wherein the second hole section 15b communicates with the valve cavity 11 through the first hole section 15a, the gland 52 is arranged in the first hole section 15a, and the pressure cap 51 is threadedly connected to the second hole section 15b. Based on this arrangement, the sealing of the first hole section 15a can be ensured by the cooperation between the gland 52 and the inner wall of the first hole section 15a, effectively preventing the fracturing fluid from leaking; the second hole section 15b can be sealed by the cooperation between the pressure cap 51 and the second hole section 15b, and the extrusion of the gland 52 by the pressure cap 51 can also be achieved.

[0045] Optionally, as shown in Figure 2As shown, the diameter D3 of the plunger 20 is smaller than the diameter D2 of the first hole section 15a, and the diameter D2 of the first hole section 15a is smaller than the diameter D1 of the second hole section 15b. Based on such 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 first hole section 15a, the smaller the pressure of the fracturing fluid on the pressure cover 52, and the smaller the force on the pressure cap 51, which is conducive to improving the service life of the external thread of the pressure cap 51. Therefore, the embodiments of the present application control the reduction of the suction hole diameter by making D3 < D2 < D1, so as to reduce the force on the external thread structure of the pressure cover 52.

[0046] In other embodiments, as shown in FIG. 2, the valve box 10 can include a box body 10a and a fixed seat 10b, and the fixed seat 10b is detachably connected with the box body 10a. It should be noted that such arrangement changes the structure of the valve box 10, so that even if the external thread structure of the pressure cap 51 is fatigued and cracked, it will not extend to the box body 10a, and only the fixed seat 10b needs to be replaced, thereby effectively protecting the box body 10a and reducing the cost. Optionally, the fixed seat 10b can be connected with the box body 10a by screwing, clamping, inserting or the like, so as to facilitate disassembly and assembly. Figure 4

[0047] Further, the pressure cover 52 is arranged in the first hole 15c, and the pressure cap 51 is threadedly connected with the second hole 15d. Based on this, the cooperation between the pressure cover 52 and the inner wall of the first hole 15c can ensure the sealing performance of the first hole 15c and effectively prevent the fracturing fluid from leaking, and the cooperation between the pressure cap 51 and the second hole 15d can not only realize the extrusion of the pressure cover 52 by the pressure cap 51, but also seal the second hole 15d by the cooperation between the pressure cap 51 and the second hole 15d.

[0048] 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 such 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 first hole section 15a, the smaller the pressure of the fracturing fluid on the pressure cover 52, and the smaller the force on the pressure cap 51, which is conducive to improving the service life of the external thread of the pressure cap 51. Therefore, the embodiments of the present application control the reduction of the suction hole diameter by making D3 < D2 < D1, so as to reduce the force on the external thread structure of the pressure cover 52.

[0049] ​In some more specific embodiments, the box body 10a can be provided with a first mounting hole (not shown in the figure), the fixing seat 10b can be provided with a second mounting hole (not shown in the figure), the fixing seat 10b is arranged on the side of the box body 10a, and the second mounting hole is arranged opposite to the first mounting hole; in addition, the valve box 10 can further include a fastener 16, the fastener 16 is arranged in the first mounting hole and the second mounting hole, so as to fasten the fixing seat 10b to the side of the box body 10a. For example, the first mounting hole can be a threaded hole, the second mounting hole can be a hole without threads, and the fastener 16 can be a fastening bolt, a fastening screw or the like.

[0050] Of course, in other embodiments, the fixing seat 10b and the box body 10a can also be fixedly connected, such as welding, riveting or the like, so as to ensure the reliability of the connection.

[0051] In order to further improve the sealing performance, the fluid end can further include a sealing member 60, which is arranged between at least part of the plugging assembly 50 and the valve hole 15, so as to seal the connection between the plugging assembly 50 and the valve hole 15. Based on this arrangement, the sealing performance between the plugging assembly 50 and the valve hole 15 can be improved by arranging the sealing member 60, so as to effectively prevent the fracturing liquid from leaking. For example, the sealing member 60 can be a sealing ring.

[0052] Optionally, the sealing member 60 can be arranged between the gland 52 and the first hole section 15a or the first hole 15c of the valve hole 15; or arranged between the cap 51 and the second hole section 15b or the second hole 15d of the valve hole 15; or arranged between the gland 52 and the first hole section 15a or the first hole 15c of the valve hole 15, and arranged between the cap 51 and the second hole section 15b or the second hole 15d of the valve hole 15 at the same time, as long as the fracturing liquid can be prevented from leaking, and the specific mode is not limited.

[0053] Based on the above-mentioned fluid end of the plunger pump, the embodiment of the present application further discloses a plunger pump, the disclosed plunger pump includes the above-mentioned fluid end, in addition to which, the plunger pump can further include a driving part, so as to drive the fluid end to operate through the driving part. It should be noted that the specific structure of the plunger pump and its working principle can refer to related technologies, and will not be described in detail here.

[0054] To sum up, the embodiment of the application realizes the optimization of the hydraulic end, specifically including: by making D3D2D1, the size of the suction hole diameter is reduced, so that in the case of a certain pressure in the valve cavity 11, the force acting on the outer thread structure of the pressure cap 51 is smaller, which is beneficial to improve the service life of the outer thread structure; the stress concentration at the root of the screw thread 511 is reduced by the setting of the arc-shaped structure 512, and the strength and deformation resistance of the screw thread 511 are improved. Therefore, the embodiment of the application can effectively solve the problem of fatigue cracking of the outer thread structure of the pressure cap 51 of the hydraulic end after long-term use, improve the service life of the plunger pump, reduce the maintenance cost, and improve the operation efficiency.

[0055] The embodiments of the application are described above in combination with the drawings, but the application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative but not restrictive. Those skilled in the art can make many forms under the inspiration of the application without departing from the scope of the application and the protection scope of the claims.

Claims

1. A fluid end of a plunger pump, characterized by, The hydraulic end comprises a valve box (10), a plunger (20), a first valve element (30), a second valve element (40) and a sealing element (50); The valve box (10) is provided with a valve cavity (11), a plunger channel (12), a liquid inlet (13), a liquid outlet (14) and a valve hole (15), the plunger channel (12) is communicated with the valve cavity (11), the valve hole (15) is communicated with the valve cavity (11) and is oppositely arranged with the plunger channel (12) in a first direction, the liquid inlet (13) and the liquid outlet (14) are respectively communicated with the valve cavity (11), and the liquid inlet (13) and the liquid outlet (14) are oppositely arranged in a second direction, the first direction is perpendicular to the second direction; The plunger (20) is movably arranged in the plunger channel (12), the first valve element (30) is arranged at the liquid inlet (13), the second valve element (40) is arranged at the liquid outlet (14), and the sealing element (50) is arranged at the valve hole (15); The sealing element (50) comprises a pressure cap (51), an outer thread structure is arranged on the outer circumferential surface of the pressure cap (51), and the fillet range of the root of the thread (511) of the outer thread structure is R0.6mm~R1.5mm; An inner thread structure is arranged on the hole wall of the valve hole (15), and the inner thread structure is connected with the outer thread structure in a matched mode.

2. The fluid end of claim 1, wherein, The outer thread structure with a length of 1 inch comprises three complete threads (511).

3. The fluid end of claim 2, wherein, Each thread (511) comprises a first inclined surface (5111) and a second inclined surface (5112), and the first inclined surface (5111) is located on the side of the second inclined surface (5112) close to the valve cavity (11); The first inclined surface (5111) and the second inclined surface (5112) of each thread (511) are respectively located on the opposite sides of a first plane (M), the included angle between the first inclined surface (5111) and the first plane (M) is 45°, and the included 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 fluid end of claim 3, wherein, An arc structure (512) is arranged between adjacent two threads (511). In adjacent two threads (511), the first inclined surface (5111) of the thread (511) close to the valve cavity (11) is transitionally connected with the second inclined surface (5112) of the thread (511) away from the valve cavity (11) through the arc structure (512).

5. The fluid end of claim 4, wherein, At least part of the arc structure (512) is a circular arc structure, and the radius range of the circular arc structure is 0.6mm~1.5mm.

6. The fluid end of claim 1, wherein, The valve hole (15) comprises a first hole section (15a) and a second hole section (15b), and the second hole section (15b) is communicated with the valve cavity (11) through the first hole section (15a). The plugging assembly (50) further comprises a gland (52) arranged in the first hole section (15a), and the gland 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 hole section (15a), and the diameter of the first hole section (15a) is smaller than the diameter of the second hole section (15b).

7. The fluid end of claim 1, wherein, The valve box (10) comprises a box body (10a) and a fixing base (10b) detachably connected with the box body (10a). The valve hole (15) comprises a first hole (15c) and a second hole (15d), the first hole (15c) is arranged in the box body (10a), and the second hole (15d) is arranged in the fixing base (10b) and communicates with the valve cavity (11) through the first hole (15c). The plugging assembly (50) further comprises a gland (52) arranged in the first hole section (15a), and the gland 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 hole section (15a), and the diameter of the first hole section (15a) is smaller than the diameter of the second hole section (15b).

8. The fluid end of claim 7, wherein, The box body (10a) is provided with a first mounting hole, the fixing base (10b) is provided with a second mounting hole, the fixing base (10b) is arranged 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) further comprises a fastener (16) arranged in the first mounting hole and the second mounting hole to fasten the fixing base (10b) to the side of the box body (10a).

9. The fluid end of claim 1, wherein, The hydraulic end further comprises a sealing member (60) arranged between at least part of the plugging assembly (50) and the valve hole (15) to sealingly connect the plugging assembly (50) and the valve hole (15).

10. A piston pump characterized in that The hydraulic end comprises any one of claims 1 to 9.

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