Sand prevention sealing valve for wellhead fracturing

Abstract

The invention discloses a sand prevention sealing valve for wellhead fracturing, and relates to the technical field of wellhead fracturing equipment. The valve comprises a valve body, valve plates and valve plate sealing assemblies. Each valve plate sealing assembly comprises a first inner sealing sleeve, an elastic assembly, a second inner sealing sleeve and a gap sealing assembly. One end of the first inner sealing sleeve is tightly connected with the inner side wall of the valve body, and an inner cavity of the first inner sealing sleeve communicates with the flow channel. One end of the second inner sealing sleeve abuts against the elastic assembly, the end face of the other end of the second inner sealing sleeve abuts against the plate face of the valve plate, and sealing of the connecting gap of the first inner sealing sleeve and the second inner sealing sleeve is achieved through the gap sealing assembly. The second inner sealing sleeve can move towards the valve plate under the pressure action of the elastic assembly and / or fluid, metal sealing between the second inner sealing sleeve and the valve plate is achieved, the sealing effect is better along with increase of the pressure intensity of the fluid, and therefore particulate matter carried in the fluid is effectively prevented from entering the sealing face between the valve plate and the second inner sealing sleeve.

Description

Technical Field

[0001] The invention relates to the technical field of wellhead fracturing equipment, and more particularly to a sand-proof sealing valve for wellhead fracturing. Background Art

[0002] The wellhead fracturing valve is a valve specially designed for oil and gas well fracturing operations. Its main function is to control the flow of fluid under high pressure environment and ensure the sealing of the wellhead. During the fracturing process, the wellhead fracturing valve can withstand extremely high pressure and temperature, prevent fluid leakage, and ensure the safety of fracturing operations.

[0003] The existing wellhead fracturing valve includes a valve body, a valve plate and a driving mechanism that drives the valve plate to open or close. When the valve plate is opened during use, a high-pressure fluid channel is established, and when the valve plate is closed, the fluid channel is cut off. The valve plate needs to be opened and closed frequently during use, and the extremely small particles (such as sand) contained in the circulating liquid can easily enter the sealing surface between the valve plate and the valve body, and the sealing surface is worn, causing the equipment to fail to work normally. Especially in existing fracturing operations, the extremely small particles contained in the fracturing fluid, some of which are as large as 200 mesh, are more likely to enter the sealing surface between the valve plate and the valve body and even enter the driving equipment or manifold equipment through the sealing surface, causing the wellhead driving equipment and manifold equipment to fail quickly, greatly reducing their service life, seriously affecting the operation efficiency, and greatly increasing the operation risk. Summary of the invention

[0004] In view of this, the present invention aims to provide a sand-proof sealing valve for wellhead fracturing to solve the technical problem in the prior art that when the wellhead fracturing valve is used in a situation containing extremely small particles (silt, etc.), the particles enter the sealing surface, reduce the sealing effect, and even cause the sealing failure.

[0005] In order to achieve the above object, the present invention adopts the following technical solution:

[0006] A sand-proof sealing valve for wellhead fracturing, comprising:

[0007] A valve body, wherein a flow channel penetrating through two opposite end walls is formed in the valve body;

[0008] A valve plate, one end of which is connected to a driving mechanism, and the other end of which is slidably connected to the inner cavity of the valve body along a direction perpendicular to the flow direction of the flow channel, and a liquid hole which can communicate with the flow channel is opened in the middle of the valve plate;

[0009] A valve plate sealing assembly, wherein the valve plate sealing assembly is provided with two groups and the two groups of valve plate sealing assemblies are symmetrically arranged on both sides of the valve plate; each group of the valve plate sealing assemblies comprises a first inner sealing sleeve, an elastic assembly, a second inner sealing sleeve and a gap sealing assembly; one end of the first inner sealing sleeve is tightly connected to the inner wall of the valve body and its inner cavity is connected to the flow channel, and one end of the elastic assembly is fixed to the end of the other end of the first inner sealing sleeve; one end of the second inner sealing sleeve abuts against the elastic assembly, and the end face of the other end abuts against the plate surface of the valve plate, a sealing sleeve at one end of the gap sealing assembly is arranged on the outer side wall of the first inner sealing sleeve, and the other end is slidably connected to the outer side wall of the second inner sealing sleeve to achieve sealing at the connection gap between the first inner sealing sleeve and the second inner sealing sleeve.

[0010] The beneficial effects that can be achieved by the present invention are as follows: after the sealing valve is installed, since the first inner sealing sleeve is fixed to the valve body, the elastic force of the elastic component is mainly used to push the second inner sealing sleeve to slide toward the side of the valve plate to achieve sealing. When fluid passes through, the fluid enters the gap between the first inner sealing sleeve and the second inner sealing sleeve, and the pressure of the fluid will also push the second inner sealing sleeve to slide toward the side of the valve plate, thereby enhancing the sealing effect and preventing particles from entering the sealing surface between the second inner sealing sleeve and the valve plate to cause sealing failure and significantly reduce the life of the valve, and even enter the drive mechanism or manifold equipment through the sealing surface, seriously affecting the operating efficiency and significantly increasing the operating risk.

[0011] Preferably, an annular positioning groove penetrating through the inner wall of the valve body is formed on the inner wall of the flow channel, and one end of the first inner sealing sleeve away from the valve plate is positioned and connected in the annular positioning groove and its inner cavity is communicated with the flow channel.

[0012] Preferably, the gap sealing assembly includes a connecting flange and an outer sealing sleeve, the connecting flange is connected to the middle part of the outer side wall of the first inner sealing sleeve; the outer sealing sleeve is fixed to the side of the connecting flange close to the valve plate, the end of the first inner sealing sleeve close to the valve plate is sleeved in the inner cavity of the outer sealing sleeve, and the end of the second inner sealing sleeve away from the valve plate is slidably connected in the inner cavity of the outer sealing sleeve.

[0013] Preferably, the gap sealing assembly further includes a first sealing ring, which is installed at a connection between the first inner sealing sleeve and the outer sealing sleeve and at a connection between the second inner sealing sleeve and the outer sealing sleeve.

[0014] Preferably, the second inner sealing sleeve is in a stepped cylindrical structure, which includes a first sleeve and a second sleeve with an outer diameter smaller than that of the first sleeve; a limiting convex ring is formed on the inner wall of the outer sealing sleeve near one end of the valve plate; the first sleeve sliding sleeve is arranged on the inner wall of the outer sealing sleeve and one end of the first sleeve can abut against the elastic component, and there is a gap between the other end and the limiting convex ring; one end of the second sleeve is integrally connected with the first sleeve, and the other end passes through the inner cavity of the limiting convex ring and is sealed with the sealing plate surface of the valve plate; the first sealing ring is provided at the connection between the first sleeve and the outer sealing sleeve and at the connection between the second sleeve and the limiting convex ring.

[0015] Preferably, the elastic component includes a first spring and a sealing pressure ring, an annular groove is provided on the end surface of the first inner sealing sleeve close to one end of the valve plate, and a plurality of first mounting grooves are evenly spaced circumferentially at the bottom of the annular groove, a plurality of first springs correspond to each other one by one and are fixed in the first mounting groove, the sealing pressure ring is slidably connected in the annular groove along the flow direction of the flow channel, and one end of the sealing pressure ring is fixed to the other end of the plurality of first springs, and the other end abuts against the end surface of the first sleeve away from the valve plate.

[0016] Preferably, a second sealing ring is installed at the connection between the inner ring wall of the sealing pressure ring and the inner ring groove wall of the annular groove, and at the connection between the outer ring wall of the sealing pressure ring and the outer ring groove wall of the annular groove.

[0017] Preferably, the second inner sealing sleeve is a stepped cylindrical structure, which includes a first sleeve and a second sleeve with an inner diameter larger than that of the first sleeve. A retaining ring is fixed to the end face of the first inner sealing sleeve close to one end of the valve plate and corresponding to the inner circumference of the elastic component. An annular cavity is formed between the retaining ring and the outer sealing sleeve. One end of the first sleeve is slidably inserted into the annular cavity along the flow direction of the flow channel and its end face abuts against the elastic component. One end of the second sleeve is integrally connected to the other end of the first sleeve, and the end face of the other end is sealed with the valve plate. The first sealing ring is provided at the connection between the first sleeve and the outer sealing sleeve and at the connection between the second sleeve and the outer sealing sleeve.

[0018] Preferably, the elastic component includes a plurality of second springs, and a plurality of second mounting grooves are evenly spaced circumferentially on the end surface of the first inner sealing sleeve close to the valve plate. The second spring corresponds one-to-one to the plurality of second mounting grooves and one end is fixed in the second mounting groove, and the other end abuts against the end surface of the first sleeve away from the valve plate.

[0019] Preferably, a third sealing ring is installed at the connection between the retaining ring and the first sleeve.

[0020] Through the above technical scheme, it can be known that compared with the prior art, the present invention discloses a sand-proof sealing valve for wellhead fracturing, which has the following beneficial effects: when no fluid passes through or the fluid pressure is small, the second inner sealing sleeve is pushed to slide toward the valve plate through the elastic component to achieve metal sealing with the valve plate; as the fluid pressure increases, when the elastic component can no longer continue to push the second inner sealing sleeve to slide, the fluid pressure acting on the second inner sealing sleeve can still drive the second inner sealing sleeve to slide toward the valve plate, thereby enhancing the sealing effect, and the greater the fluid pressure, the greater the fluid pressure applied to the second inner sealing sleeve, and the better the sealing effect, thereby effectively preventing particles carried in the fluid from entering the sealing surface between the valve plate and the second inner sealing sleeve, preventing the sealing surface of the valve plate and the second inner sealing sleeve from being worn and the sealing failing, thereby preventing particles from entering the drive mechanism or other manifold equipment and affecting the normal operation of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0022] Figure 1 This is a schematic structural diagram of a sand-proof sealing valve structure for wellhead fracturing provided in Example 1 of the present invention in a fully closed state.

[0023] Figure 2 for Figure 1 Schematic diagram of the enlarged structure of part C in the middle.

[0024] Figure 3 This is a schematic structural diagram of the valve plate sealing assembly provided in Example 1 of the present invention.

[0025] Figure 4 This is a schematic structural diagram of a sand-proof sealing valve structure for wellhead fracturing provided in Example 1 of the present invention in a fully open state.

[0026] Figure 5 for Figure 4 A schematic diagram of the enlarged structure of part A.

[0027] Figure 6 This is a schematic structural diagram of a sand-proof sealing valve structure for wellhead fracturing in a half-open and half-closed state provided in Example 1 of the present invention.

[0028] Figure 7 for Figure 6 The enlarged structural diagram of part B is shown in the figure.

[0029] Figure 8This is a schematic structural diagram of a sand-proof sealing valve structure for wellhead fracturing in a half-open and half-closed state provided in Example 2 of the present invention.

[0030] Fig. 9 This is a schematic structural diagram of the valve plate sealing assembly provided in Example 2 of the present invention.

[0031] In the figure: 1, valve body, 11, flow channel, 12, annular positioning groove, 2, valve plate, 21, liquid hole, 3, valve plate sealing assembly, 31, first inner sealing sleeve, 311, annular slide groove, 312, first mounting groove, 313, retaining ring, 314, second mounting groove, 32, gap sealing assembly, 321, connecting flange, 322, outer sealing sleeve, 3221, limiting convex ring, 323, first sealing ring, 33, second inner sealing sleeve, 331, first sliding sleeve, 332, second sliding sleeve, 333, first sleeve, 334, second sleeve, 335, third sealing ring, 34, elastic assembly, 341, first spring, 342, sealing pressure ring, 343, second sealing ring, 344, second spring, 4, fourth sealing ring, 5, bolt. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0034] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] See also Figure 1-Figure 9The embodiment of the present invention discloses a sand-proof sealing valve for wellhead fracturing, comprising:

[0036] A valve body 1, wherein a flow channel 11 penetrating through the two end walls is formed in the valve body 1;

[0037] A valve plate 2, one end of which is connected to the driving mechanism, and the other end of which is slidably connected to the inner cavity of the valve body 1 along the flow direction of the vertical flow channel 11. A liquid hole 21 which can communicate with the flow channel 11 is opened in the middle of the valve plate 2;

[0038] The valve plate sealing assembly 3 is provided with two groups of valve plate sealing assemblies 3 and the two groups of valve plate sealing assemblies 3 are symmetrically arranged on both sides of the valve plate 2; each group of valve plate sealing assemblies 3 includes a first inner sealing sleeve 31, an elastic assembly 34, a second inner sealing sleeve 33 and a gap sealing assembly 32; one end of the first inner sealing sleeve 31 is tightly connected to the inner wall of the valve body 1 and its inner cavity is connected to the flow channel 11, and one end of the elastic assembly 34 is fixed to the end of the other end of the first inner sealing sleeve 31; one end of the second inner sealing sleeve 33 abuts against the elastic assembly, and the end face of the other end abuts against the plate surface of the valve plate 2, one end of the gap sealing assembly 32 is sealed on the outer wall of the first inner sealing sleeve 31, and the other end is slidably connected to the outer wall of the second inner sealing sleeve 33, so as to realize the sealing at the connection gap between the first inner sealing sleeve 31 and the second inner sealing sleeve 33.

[0039] The second inner sealing sleeve 33 and the valve plate 2 are both made of metal, and can achieve metal sealing.

[0040] After the sealing valve of the embodiment of the present invention is installed, since the first inner sealing sleeve 31 is fixed to the valve body 1, the elastic force of the elastic component 34 is mainly used to push the second inner sealing sleeve 33 to slide toward the valve plate 2 to achieve a metal seal with the valve plate 2; when fluid passes through, the fluid enters the connection gap between the first inner sealing sleeve 31 and the second inner sealing sleeve 33, and the pressure of the fluid will also push the second inner sealing sleeve 33 to slide toward the valve plate 2, thereby enhancing the sealing effect and preventing particles from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2 to cause sealing failure, thereby significantly reducing the life of the valve, and even entering the drive mechanism or manifold equipment through the sealing surface, thereby seriously affecting the operating efficiency and significantly increasing the operating risk.

[0041] The inner wall of the flow channel 11 is provided with an annular positioning groove 12 which passes through the inner wall of the valve body 1. One end of the first inner sealing sleeve 31 away from the valve plate 2 is positioned and connected in the annular positioning groove 12, and its inner cavity is connected with the flow channel 11. It is used to install and limit the first inner sealing sleeve 31 to prevent the first inner sealing sleeve 31 from sliding in the direction perpendicular to the flow channel 11.

[0042] A fourth sealing ring 4 is installed at the connection between the first inner sealing sleeve 31 and the annular positioning groove 12 .

[0043] The gap sealing assembly 32 includes a connecting flange 321 and an outer sealing sleeve 322. The connecting flange 321 is connected to the middle of the outer wall of the first inner sealing sleeve 31. The outer sealing sleeve 322 is fixed to the side of the connecting flange 321 close to the valve plate 2 by bolts 5. The end of the first inner sealing sleeve 31 close to the valve plate 2 is sleeved in the inner cavity of the outer sealing sleeve 322, and the end of the second inner sealing sleeve 33 away from the valve plate 2 is slidably connected in the inner cavity of the outer sealing sleeve 322. The connecting flange 321 and the outer sealing sleeve 322 are detachable, which is convenient for the installation of the first inner sealing sleeve 31 and the second inner sealing sleeve 33. The connecting flange 321 and the first inner sealing sleeve 31 can be integrally connected or detachable. When detachable, the first inner sealing sleeve 31 is a stepped cylindrical structure, including a first connecting sleeve and a second connecting sleeve with an outer diameter larger than the first connecting sleeve. The first connecting sleeve is inserted into the annular positioning groove 12, and the shoulder of the second connecting sleeve is limitedly connected with the connecting flange 321.

[0044] The gap sealing assembly 32 further includes a first sealing ring 323 , which is installed at the connection between the first inner sealing sleeve 31 and the outer sealing sleeve 322 and at the connection between the second inner sealing sleeve 33 and the outer sealing sleeve 322 to prevent fluid leakage.

[0045] Embodiment 1:

[0046] See also Figure 1-Figure 7 In this embodiment, the second inner sealing sleeve 33 is a stepped cylindrical structure, which includes a first sliding sleeve 331 and a second sliding sleeve 332 with an outer diameter smaller than that of the first sliding sleeve 331. A limiting convex ring 3221 is formed on the inner side wall of the outer sealing sleeve 322 near one end of the valve plate 2. The first sliding sleeve 331 is slidingly sleeved on the inner side wall of the outer sealing sleeve 322 and one end of the first sliding sleeve 331 can abut against the elastic component 34, and there is a gap between the end face of the other end and the limiting convex ring 3221; one end of the second sliding sleeve 332 is integrally connected with the first sliding sleeve 331, and the other end passes through the inner cavity of the limiting convex ring 3221 and is sealed and connected with the sealing plate surface of the valve plate 2. An annular low-pressure cavity is formed in the gap between the first sliding sleeve 331, the second sliding sleeve 332, the outer sealing sleeve 322 and the limiting convex ring 3221, which reduces the air resistance when the second inner sealing sleeve 33 slides along the flow direction of the flow channel 11 under the elastic force of the elastic component 34 or the fluid pressure, thereby enhancing the sealing effect with the valve plate 2.

[0047] The first sealing ring 323 is provided at the connection between the first sliding sleeve 331 and the outer sealing sleeve 322 and at the connection between the second sliding sleeve 332 and the limiting convex ring 3221. The second inner sealing sleeve 33 and the connection parts of each part are sealed to prevent liquid from entering.

[0048] The elastic component 34 includes a first spring 341 and a sealing pressure ring 342. An annular groove 311 is provided on the end surface of the first inner sealing sleeve 31 close to one end of the valve plate 2, and a plurality of first installation grooves 312 are evenly spaced at the bottom of the annular groove 311 in the circumferential direction. The plurality of first springs 341 correspond to each other and are fixed in the first installation groove 312. The sealing pressure ring 342 is slidably connected in the annular groove 311 along the flow direction of the flow channel 11, and one end of the sealing pressure ring is fixed to the other end of the plurality of first springs 341, and the other end is in contact with the end surface of the first sliding sleeve 331 away from the valve plate 2. The sealing pressure ring 342 is provided to prevent the fluid from entering and affecting the expansion and contraction of the first spring 341. At the same time, the sealing pressure ring 342 can expand and contract synchronously with the first spring 41, driving the second inner sealing sleeve 33 to slide and realize the sealing connection with the valve plate 2.

[0049] The sealing pressure ring 342 is a rigid ring, and a second sealing ring 343 is installed at the connection between the inner ring wall and the inner ring groove wall of the annular groove 311, as well as at the connection between the outer ring wall of the sealing pressure ring 342 and the outer ring groove wall of the annular groove 311, to prevent liquid from entering through the gap at the connection to corrode the first spring 341 and affect the service life of the first spring 341.

[0050] The sealing principle of this embodiment is as follows:

[0051] Valve plate 2 is fully open:

[0052] like Figure 4 , 5 As shown, the inner cavity Q3 of the valve body on the outer peripheral side of the valve plate sealing component 3 is filled with sealing grease. When the valve plate 2 is fully opened, the initial fluid pressure is low. Since the elastic component 34 is in a compressed state, the first inner sealing sleeve 31 and the second inner sealing sleeve 33 are separated from each other, and the first inner sealing sleeve 31 is clamped in the annular positioning groove 12 and cannot move or can only move a small distance. Therefore, most of the elastic force of the elastic component 34 acts on the second inner sealing sleeve 33, pushing the second inner sealing sleeve 33 to move toward the valve plate 2 and seal with the valve plate 2. After the valve plate 2 is opened, the fluid enters the gap between the first inner sealing sleeve 31 and the second inner sealing sleeve 33. The end face of the second inner sealing sleeve 33 away from the valve plate 2 is subjected to the fluid pressure F1 and the thrust of the sealing pressure ring 342. At this time, the elastic force F3 of the first spring 341 on the sealing pressure ring 342 is much greater than the fluid pressure F4 on the end face close to the valve plate 2. The thrust of the sealing pressure ring 342 on the second inner sealing sleeve 33 is greater than zero. The second inner sealing sleeve 33 slides toward the valve plate 2 under the combined action of the fluid pressure and the thrust of the sealing pressure ring 342, so that the second inner sealing sleeve 33 is in close contact with the sealing surface of the valve plate 2 to achieve metal sealing.

[0053] As the fluid pressure increases, the fluid force F4 on the lower end face of the sealing pressure ring 342 gradually increases. When F4>F3, the sealing pressure ring 342 is pressed to the bottom of the annular slide groove 311, the first spring 341 is compressed, and cannot push the sealing pressure ring 342 to move downward. The sealing pressure ring 342 cannot contact the second inner sealing sleeve 33 to push the second inner sealing sleeve 33 to slide. However, at this time, the fluid pressure is relatively large, F1 is relatively large, and the second inner sealing sleeve 33 is only tightly fitted with the sealing surface of the valve plate 2 under the action of the fluid pressure F1. As the pressure increases, F1 increases, and the sealing effect is better, thereby effectively preventing tiny particles in the fluid from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2. During the whole process, the internal pressure of the annular low-pressure cavity Q4 is very low, and the air resistance F2 acting on the first sliding sleeve 331 is very small relative to F1 and can be ignored. The two sets of valve plate sealing assemblies 3 on both sides of the valve plate 2 have the same sealing principle, thereby realizing bidirectional sealing of the valve plate 2.

[0054] Valve plate 2 is fully closed:

[0055] like Figure 1 , 2 As shown, when the valve plate 2 is fully closed, the fluid is cut off, and the flow channel 11 is divided into two chambers, the upstream is the high-pressure chamber Q1, and the downstream is the low-pressure chamber Q2. The valve plate 2 is subjected to the pressure F5 of the high-pressure chamber Q1, which causes the valve plate 2 to elastically deform downward, and the plate surface on the low-pressure chamber side of the valve plate 2 is tightly sealed with the second inner sealing sleeve 33 of the downstream valve plate sealing assembly 3, preventing tiny particles in the fluid from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2. On the high-pressure chamber Q1 side, the second inner sealing sleeve 33 moves toward the valve plate 2 under the action of the fluid pressure F1 on its end face, compensating for the elastic deformation of the valve plate 2, thereby achieving effective sealing between the second inner sealing sleeve 33 and the plate surface on the high-pressure chamber side of the valve plate 2. The greater the pressure, the greater the force of F1, the tighter the fit between the second inner sealing sleeve 33 and the sealing surface of the valve plate 2, and the better the sealing effect.

[0056] Valve plate 2 half-open and half-closed state:

[0057] like Figure 6 , 7As shown, when the valve plate 2 is in the process of closing or opening, especially the working condition of the high-pressure switching process is the worst, the flow channel 11 is connected with the inner cavity Q3 of the valve body, and all become high-pressure areas, the second inner sealing sleeve 33 is in partial contact with the sealing surface of the valve plate 2, and the end surface fluid pressure F4 of the sealing pressure ring 342 close to the valve plate 2 gradually increases. When F4>F3, the first spring 341 is compressed and no longer pushes the second inner sealing sleeve 33 to move toward the valve plate; at this time, the fluid pressure F1 acting on the second inner sealing sleeve 33 pushes the second inner sealing sleeve 33 to move toward the valve plate 2, and the force F2 generated by the annular low-pressure cavity is very small relative to F1, and the impact is very small; the greater the pressure, the greater the force of F1, and the tighter the second inner sealing sleeve 33 fits with the valve plate 2, thereby effectively preventing tiny particles in the fluid from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2 during the switching process of the valve plate 2.

[0058] Through a detailed analysis of the valve plate 2 being fully opened, fully closed, and half-open and half-closed, as long as liquid passes through, the second inner sealing sleeve 33 and the valve plate 2 can be tightly attached in real time to achieve liquid pressure-assisted sealing, which can effectively prevent harmful particles from entering the sealing surface. As the fluid pressure increases, the greater the thrust applied to the second inner sealing sleeve 33, the better the sealing effect, thereby greatly improving the service life of the wellhead fracturing equipment.

[0059] Embodiment 2:

[0060] See also Figure 8-Figure 9 In this embodiment, the second inner sealing sleeve 33 is a stepped cylindrical structure, which includes a first sleeve 333 and a second sleeve 334 whose inner diameter is larger than that of the first sleeve 333. A retaining ring 313 is fixed to the end face of the first inner sealing sleeve 31 close to one end of the valve plate 2 and corresponding to the inner circumference of the elastic component 34. An annular cavity is formed between the retaining ring 313 and the outer sealing sleeve 322. One end of the first sleeve 333 is slidably inserted in the annular cavity along the flow direction of the flow channel 11 and its end face is in contact with the elastic component 34. One end of the second sleeve 334 is integrally connected to the other end of the first sleeve 333, and the end face of the other end is sealed with the valve plate 2. The first sleeve 333 is connected to the elastic component 34. Under the combined effect of the elastic force of the elastic component 34 acting on the first sleeve 333 and the fluid pressure of the fluid acting on the second sleeve 334, the second inner sealing sleeve 33 is pushed to slide toward the side of the valve plate 2. As the elastic component 34 gradually recovers, the elastic force decreases and cannot push the first sleeve 333 to slide. At this time, it only slides toward the valve plate 2 under the action of the fluid pressure to ensure the sealing effect. And as the fluid pressure increases, the fluid pressure acting on the second inner sealing sleeve 33 increases, and the sealing effect is better.

[0061] A first sealing ring 323 is disposed at a connection between the first sleeve 333 and the outer sealing sleeve 322 and at a connection between the second sleeve 334 and the outer sealing sleeve 322 .

[0062] The elastic component 34 includes a plurality of second springs 344. A plurality of second mounting grooves 314 are evenly spaced circumferentially on the end surface of the first inner sealing sleeve 31 close to the valve plate 2. The second spring 344 corresponds one-to-one to the plurality of second mounting grooves 314 and one end is fixed in the second mounting groove 314, and the other end abuts against the end surface of the first sleeve 333 away from the valve plate 2.

[0063] A third sealing ring 335 is installed at the connection between the retaining ring 313 and the first sleeve 333 to prevent fluid from entering and corroding the spring.

[0064] The sealing principle of this embodiment is as follows:

[0065] When valve plate 2 is fully opened:

[0066] The initial fluid pressure is low, and the first inner sealing sleeve 31 is stuck in the annular positioning groove and cannot move or can only move a small distance. At this time, the elastic force f2 of the second spring 344 is mainly used to push the second inner sealing sleeve 33 to move toward the valve plate 2. Finally, the second inner sealing sleeve 33 achieves metal sealing with the sealing surface of the valve plate 2 under the combined action of the fluid pressure f1 and the elastic force f2 of the second spring 344.

[0067] As the fluid pressure increases, the second spring 344 gradually returns to its original length and the elastic force gradually decreases, while the fluid pressure becomes greater and greater. The second inner sealing sleeve 33 moves toward the valve plate 2 mainly under the action of the fluid pressure f1, and as the fluid pressure increases, the sealing effect increases.

[0068] When valve plate 2 is fully closed:

[0069] Cut off the fluid flow, and divide the flow channel 11 into two chambers, the upstream is the high-pressure chamber Q1, and the downstream is the low-pressure chamber Q2. The valve plate 2 is subjected to the pressure F5 of the high-pressure chamber Q1, causing the valve plate 2 to elastically deform downward, and the plate surface on the low-pressure chamber side of the valve plate 2 is tightly sealed with the second inner sealing sleeve 33 of the corresponding sealing assembly valve plate sealing assembly 3, preventing tiny particles in the fluid from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2. On the high-pressure chamber Q1 side, the second inner sealing sleeve 33 moves toward the valve plate 2 under the action of its fluid pressure f1, compensating for the elastic deformation of the valve plate 2, thereby achieving effective sealing between the second inner sealing sleeve 33 and the plate surface on the high-pressure chamber side of the valve plate 2. The greater the pressure, the greater the f1, the tighter the fit between the second inner sealing sleeve 33 and the sealing surface of the valve plate 2, and the better the sealing effect.

[0070] Valve plate 2 half-open and half-closed state:

[0071] like Figure 6 , 8As shown in Figures 9, when the valve plate 2 is in the process of closing or opening, especially the working conditions of the high-pressure switching process are the worst, the flow channel 11 is connected with the inner cavity Q3 of the valve seat valve body 11, and all become high-pressure areas. The second inner sealing sleeve 33 is in partial contact with the sealing surface of the valve plate 2. As the distance between the first inner sealing sleeve 31 and the second inner sealing sleeve 33 increases, the deformation of the second spring 344 gradually recovers, and the elastic force gradually decreases. At this time, the end surface fluid pressure f1 of the second inner sealing sleeve 33 away from the side of the valve plate 2 pushes the second inner sealing sleeve 33 downward. The greater the pressure, the greater the force of f1, and the tighter the fit between the first inner sealing sleeve 31 and the valve seat valve body 1, and between the second inner sealing sleeve 33 and the valve plate 2, thereby effectively preventing tiny particles in the fluid from entering the sealing surface between the second inner sealing sleeve 33 and the valve plate 2 during the switching process of the valve plate 2.

[0072] Through a detailed analysis of the processes of the valve plate 2 being fully opened, fully closed, and half-open and half-closed, it can be seen that as long as liquid passes through, the second inner sealing sleeve 33 and the valve plate 2 can be tightly attached in real time to achieve liquid pressure-assisted sealing, which can effectively prevent harmful particles from entering the sealing surface. As the fluid pressure increases, the greater the thrust applied to the second inner sealing sleeve 33, the better the sealing effect, thereby greatly improving the service life of the wellhead fracturing equipment.

[0073] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0074] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A sand-proof sealing valve for wellhead fracturing, characterized in that: include: A valve body (1), wherein a flow channel (11) is provided in the valve body (1) and passes through two opposite end walls; a valve plate (2), one end of the valve plate (2) being connected to a driving mechanism, and the other end of the valve plate (2) being slidably connected in the inner cavity of the valve body (1) along a flow direction perpendicular to the flow channel (11), and a liquid passage hole (21) being provided in the middle of the valve plate (2) and being communicated with the flow channel (11); A valve plate sealing assembly (3), wherein the valve plate sealing assembly (3) is provided with two groups and the two groups of the valve plate sealing assemblies (3) are symmetrically arranged on both sides of the valve plate (2); each group of the valve plate sealing assemblies (3) comprises a first inner sealing sleeve (31), an elastic assembly (34), a second inner sealing sleeve (33) and a gap sealing assembly (32); one end of the first inner sealing sleeve (31) is tightly connected to the inner side wall of the valve body (1) and its inner cavity is connected to the flow channel (11); one end of the elastic assembly (34) is fixed to the end of the other end of the first inner sealing sleeve (31); one end of the second inner sealing sleeve (33) is in contact with the elastic assembly, and the end face of the other end is in contact with the plate surface of the valve plate (2); one end of the gap sealing assembly (32) is provided with a sealing sleeve on the outer side wall of the first inner sealing sleeve (31), and the other end is slidably connected to the outer side wall of the second inner sealing sleeve (33) to achieve sealing at the connection gap between the first inner sealing sleeve (31) and the second inner sealing sleeve (33).

2. A sand-proof sealing valve for wellhead fracturing according to claim 1, characterized in that: The inner wall of the flow channel (11) is provided with an annular positioning groove (12) which passes through the inner wall of the valve body (1); one end of the first inner sealing sleeve (31) away from the valve plate is positioned and connected in the annular positioning groove (12) and its inner cavity is in communication with the flow channel (11).

3. A sand-proof sealing valve for wellhead fracturing according to claim 2, characterized in that: The gap sealing assembly (32) comprises a connecting flange (321) and an outer sealing sleeve (322), wherein the connecting flange (321) is connected to the middle part of the outer side wall of the first inner sealing sleeve (31); the outer sealing sleeve (322) is fixed to the connecting flange (321) on the side close to the valve plate (2), the end of the first inner sealing sleeve (31) close to the valve plate (2) is sleeved in the inner cavity of the outer sealing sleeve (322), and the end of the second inner sealing sleeve (33) away from the valve plate (2) is slidably connected in the inner cavity of the outer sealing sleeve (322).

4. A sand-proof sealing valve for wellhead fracturing according to claim 3, characterized in that: The gap sealing assembly (32) further comprises a first sealing ring (323), wherein the first sealing ring (323) is installed at the connection between the first inner sealing sleeve (31) and the outer sealing sleeve (322) and at the connection between the second inner sealing sleeve (33) and the outer sealing sleeve (322).

5. A sand-proof sealing valve for wellhead fracturing according to claim 4, characterized in that: The second inner sealing sleeve (33) is in a stepped cylindrical structure, comprising a first sliding sleeve (331) and a second sliding sleeve (332) having an outer diameter smaller than that of the first sliding sleeve (331); a limiting convex ring (3221) is formed on the inner wall of the outer sealing sleeve (322) near one end of the valve plate (2); the first sliding sleeve (331) is slidingly sleeved on the inner wall of the outer sealing sleeve (322) and one end of the first sliding sleeve (331) can abut against the elastic component (34), and a gap is formed between the other end and the limiting convex ring (3221); one end of the second sliding sleeve (332) is integrally connected with the first sliding sleeve (331), and the other end passes through the inner cavity of the limiting convex ring (3221) and is sealed with the sealing plate surface of the valve plate (2); the first sealing ring (323) is provided at the connection between the first sliding sleeve (331) and the outer sealing sleeve (322) and at the connection between the second sliding sleeve (332) and the limiting convex ring (3221).

6. A sand-proof sealing valve for wellhead fracturing according to claim 5, characterized in that: The elastic component (34) includes a first spring (341) and a sealing pressure ring (342). An annular groove (311) is provided on the end surface of the first inner sealing sleeve (31) close to one end of the valve plate (2), and a plurality of first mounting grooves (312) are evenly spaced at the bottom of the annular groove (311). The plurality of first springs (341) correspond to each other one by one and are fixed in the first mounting grooves (312). The sealing pressure ring (342) is slidably connected in the annular groove (311) along the flow direction of the flow channel (11), and one end of the sealing pressure ring is fixed to the other end of the plurality of first springs (341), and the other end abuts against the end surface of the first sleeve (331) away from the valve plate (2).

7. A sand-proof sealing valve for wellhead fracturing according to claim 6, characterized in that: A second sealing ring (343) is installed at the connection between the inner ring wall of the sealing pressure ring (342) and the inner ring groove wall of the annular slide groove (311), and at the connection between the outer ring wall of the sealing pressure ring (342) and the outer ring groove wall of the annular slide groove (311).

8. A sand-proof sealing valve for wellhead fracturing according to claim 4, characterized in that: The second inner sealing sleeve (33) is a stepped cylindrical structure, comprising a first sleeve (333) and a second sleeve (334) having an inner diameter greater than that of the first sleeve (333). A retaining ring (313) is fixed to the end surface of the first inner sealing sleeve (31) close to one end of the valve plate (2) and corresponding to the inner circumference of the elastic component (34). An annular cavity is formed between the retaining ring (313) and the outer sealing sleeve (322). One end of the first sleeve (333) is disposed along the flow channel. The second sleeve (334) is slidably inserted in the annular cavity in the flow direction and its end face is in contact with the elastic component (34). One end of the second sleeve (334) is integrally connected to the other end of the first sleeve (333), and the end face of the other end is sealed with the valve plate (2). The first sealing ring (323) is provided at the connection between the first sleeve (333) and the outer sealing sleeve (322) and at the connection between the second sleeve (334) and the outer sealing sleeve (322).

9. A sand-proof sealing valve for wellhead fracturing according to claim 8, characterized in that: The elastic component (34) includes a plurality of second springs (344); a plurality of second mounting grooves (314) are evenly spaced circumferentially arranged on the end surface of the first inner sealing sleeve (31) close to the valve plate (2); the second spring (344) corresponds to the plurality of second mounting grooves (314) one by one and one end of the second spring is fixed in the second mounting groove (314), and the other end abuts against the end surface of the first sleeve (333) away from the valve plate (2).

10. A sand-proof sealing valve for wellhead fracturing according to claim 9, characterized in that: A third sealing ring (335) is installed at the connection between the retaining ring (313) and the first sleeve (333).

Images