An oilfield water injection throttle regulating stop valve

Abstract

An oilfield water injection throttling and regulating shut-off valve has three independent valve seats and three corresponding sealing surfaces on the valve core. The flow inner diameter of valve seat I, valve seat II, and valve seat III increases progressively. When the valve is open, the flow velocity through the three valve seats gradually decreases, reducing scouring. The individual sealing performance of each valve seat is better with higher pressure, preventing gap scouring and particle wear phenomena that occur during minor leaks. The opening of the throttling orifice arranged on the upper circumference of the valve disc annular groove and the cylinder liner annular groove achieves the throttling function. The throttling function is only affected by the opening height of the upper convex shoulder of the valve disc and the cylinder liner throttling orifice. The lower metal sealing cone surface of the valve disc and the valve seat sealing surface are never involved. After the medium passes through the throttling and regulating part, it needs to pass through a labyrinth channel formed by the cylinder liner throttling orifice and the upper four open ring oblique holes installed in a staggered manner, and the upper and lower four open ring oblique holes installed in opposite directions. This reduces pressure and decelerates the medium, protecting the main throttling components of the valve from damage.

Description

Technical Field

[0001] This invention relates to the field of valve technology, specifically to an oilfield water injection throttling and regulating shut-off valve. Background Technology

[0002] Oilfield water injection operations are characterized by high pressure (16MPa, 25MPa, 42MPa), large pressure differential throttling, media containing silt, rust, corrosive ions, long-term small-opening regulation, and continuous 24-hour operation. Ordinary throttling valves can be damaged by the fluid, suffer sealing failure, uncontrolled regulation, and structural damage. The main reasons are: First, cavitation damage. The pressure difference across the water injection valve is generally 10~30MPa. When the medium flows through the narrow throttling gap of the valve core, the flow velocity increases sharply, and the local pressure is lower than the saturated vapor pressure of water, causing water vaporization and forming a large number of bubbles. These bubbles collapse instantly in the downstream high-pressure area, generating a 2000MPa shock wave that creates honeycomb-like pits on the valve core and valve seat sealing surfaces. This manifests as severe valve vibration and sharp whistling noise; pitting corrosion on the sealing surface quickly leads to internal leakage; long-term cavitation can penetrate the valve core and erode the valve body flow channel. Other contributing factors include long-term small-opening regulation, pressure difference across the valve >10MPa, and high dissolved gas content in the water. Secondly, there is erosion and wear from solid particles. Oilfield reinjection water carries silt, pipeline rust, and corrosive scale. High-pressure, high-speed water flow carries hard particles that continuously cut into the metal surface of the throttling zone, causing streamlined deep grooves to carve out of the throttling groove and valve seat sealing surface, resulting in loss of sealing pressure. Cavitation first creates pits, and then particles further intensify the cutting, resulting in double damage that significantly shortens the valve's service life. Therefore, under these conditions, most throttling control valves will exhibit significant internal leakage within two to three months, and their regulating function will be essentially destroyed. Summary of the Invention

[0003] In response to the harsh conditions described above, ordinary throttling valves have extremely short lifespans, which affect normal production operations and result in low production efficiency. This invention provides an oilfield water injection throttling regulating valve.

[0004] The technical solution adopted in this invention is: an oilfield water injection throttling and regulating shut-off valve, including a valve body, a valve stem provided in the valve body, a valve disc provided at the end of the valve stem, and three independent valve seats I, II, and III arranged sequentially from bottom to top in the valve seat hole of the valve body. Each of the valve seats I, II, and III is provided with a valve seat sealing surface, and the flow inner diameter of the valve seats I, II, and III increases progressively. Elastic elements are also provided between valve seats I and II, and between valve seats II and III, respectively, to provide pre-tightening force for initial sealing pre-tightening pressure and to compensate for machining errors of the three metal sealing surfaces of the valve disc. The end of the valve disc is also provided with three metal sealing surfaces that are adapted to valve seats I, II, and III respectively, and the three metal sealing surfaces on the valve disc are respectively sealed and fitted with valve seats I, II, and III.

[0005] A cylinder liner is also provided on the valve seat hole. The cylinder liner is matched with valve seat I, valve seat II, and valve seat III to ensure that valve seat I, valve seat II, and valve seat III do not come out of the valve seat hole.

[0006] The valve seats I, II, and III have axial movement between the cylinder liner limit and the valve seat hole platform; there are certain gaps between valve seats I (4) and II (5), between valve seats II (5) and III (6), and between valve seats III (6) and the lower end of the cylinder liner (8).

[0007] The outer circumferential surfaces of valve seats I, II, and III are sealed to the inner wall of the valve seat bore by O-rings.

[0008] The valve disc is designed with an increased height. The valve disc has an annular groove U in the middle and a shoulder (31) structure above the annular groove U. The cylinder liner has an extended part at the top and an annular groove V on the inner surface of the cylinder liner. When the valve is closed, the lower end of the annular groove V is flush with the upper end of the shoulder (34).

[0009] The cylinder liner is provided with a throttle hole on the extended part. When the valve is closed, the lower end face of the extended part is flush with the lower end face of the shoulder (31) structure. The distance from the throttle hole to the lower end face of the extended part is M. The distance M is greater than the length of the shoulder (34) below the annular groove U of the valve disc (3) is N (M is greater than N).

[0010] The outer circular surface of the shoulder structure slides and engages on the inner wall of the extended part of the cylinder liner to adjust the opening size of the throttling orifice. The setting of M being greater than N ensures that before the valve enters the flow regulation state, the lower shoulder (34) of the valve disc has separated from the lower inner hole of the cylinder liner (8), and the valve disc sealing surface and the valve seat sealing surface have separated by a large distance. This ensures that, except for the medium between the shoulder (31) and the throttling orifice (82) with a large pressure difference and high-speed fluid, there is no obvious pressure difference and high-speed fluid between other parts of the valve disc and the valve seat and cylinder liner.

[0011] Two layers of four-rings are provided between the cylinder liner and the valve body. The four-rings are provided with oblique holes at angle α. The oblique holes between the two layers of four-rings are installed in opposite directions and the oblique holes of the upper four-rings are installed in an offset manner with the cylinder liner throttle hole.

[0012] The valve disc is provided with a pressure hole for pressurizing the middle cavity. A cylinder ring is provided in the upper middle cavity of the cylinder liner. The inner diameter of the cylinder ring is the same as the inner diameter of the valve seat II. Together with the pressure hole, they form a self-balancing structure that can balance the upward pressure of the medium and reduce the switching torque.

[0013] The beneficial effects of this invention are as follows: This invention provides an oilfield water injection throttling and regulating shut-off valve, which has three independent valve seats and three corresponding sealing surfaces on the valve core. The flow inner diameters of valve seats I, II, and III increase progressively. When the valve is opened, the flow velocity through the three valve seats gradually decreases, and the scouring also weakens progressively. When leakage occurs after long-term use of the sealing surface between valve seat I and valve disc, the medium enters the sealing pair between valve seat II and valve disc. At this time, due to the pre-tightening of the disc spring, a specific pressure is generated to form an initial seal. The ring formed between the outer circle G of the valve seat and the inner hole B of valve seat II forms an upward force pushing valve seat II under the pressure of the medium, which increases the sealing specific pressure and is beneficial to sealing. It is also a pressure self-sealing effect. When valve seat II fails after prolonged use, the medium enters between valve seat III and the valve disc sealing pair. Under the preload of the disc spring, valve seat III achieves initial sealing of the sealing pair. The force acting on the valve seat III ring also achieves a self-sealing effect. The individual sealing performance of each valve seat improves with higher pressure, preventing erosion and particle wear caused by minor leaks, significantly extending the sealing life of each individual valve seat. The sealing performance of the three valve seats only fails after each seat gradually deteriorates. Therefore, the valve seat sealing performance of this valve is at least three times longer than that of ordinary structures. Furthermore, the pressure self-sealing performance of the valve seats makes it particularly suitable for high-pressure media, preventing erosion and wear caused by minor leaks between the sealing surfaces. The valve's throttling function does not occur in the area between the conical sealing surface below the valve disc and the conical sealing surface of the valve seat. High-speed fluid, high-pressure differential erosion, and cavitation during throttling do not occur near the sealing surface. The fluid state in this area is equivalent to a normal pipeline channel, with no abrupt changes in flow area, no significant pressure differential, no cavitation, and no high-speed fluid erosion of the sealing surface. Therefore, its sealing life is more than ten times that of ordinary structure valves. The valve's throttling function is located far from the valve's sealing area. The throttling component area is hardened to be wear-resistant and erosion-resistant. Even if it is partially eroded, it will not affect the valve's sealing function. The flow rate adjustment accuracy will be minimally affected, as the manual regulating valve can compensate well by appropriately adjusting the opening height according to the flow rate, without affecting the valve's regulating function and ensuring long-term use. After passing through the throttling adjustment part, the medium needs to pass through a labyrinth channel formed by the cylinder liner throttling hole and the upper four open ring oblique hole misaligned and installed, and the upper and lower four open ring oblique holes with opposite angles and misaligned installation, so that the pressure is reduced and the speed is reduced, so that the most serious damage occurs at the outlet of the labyrinth, protecting the main throttling component of the valve from serious damage. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of the present invention.

[0015] Figure 2 This is a schematic diagram of the initial state structure of the present invention.

[0016] Figure 3 This is a schematic diagram of the adjustable state structure of the present invention.

[0017] Figure 4 This is a schematic diagram of the fully open state structure of the present invention.

[0018] Figure 5 This is a schematic diagram of the closed state structure of the present invention.

[0019] Figure 6 This is a schematic diagram of the cylinder liner structure.

[0020] Figure 7 This is a schematic diagram of a four-open-ring structure.

[0021] Figure 8 This is a schematic diagram of the valve disc structure.

[0022] Wherein: 1-valve body; 2-valve stem; 3-valve disc; 4-valve seat I; 5-valve seat II; 6-valve seat III; 7-elastic element; 8-cylinder liner; 9-cylinder ring; 11-O-ring seal; 31-shoulder structure; 32-pressure hole; 33-ring groove U; 34-lower shoulder; 81-extended part; 82-throttle hole; 83-four-open ring; 84-oblique hole; 85-ring groove V. Detailed Implementation

[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0024] An oilfield water injection throttling and regulating shut-off valve includes a valve body 1, a valve stem 2 inside the valve body 1, and a valve disc 3 at the end of the valve stem 2. Three independent valve seats I4, II5, and III6 are sequentially arranged from bottom to top within the valve seat hole of the valve body 1. Each of the valve seats I4, II5, and III has a valve seat sealing cone surface, and the flow inner diameter of each valve seat increases progressively from C to B to A. When the valve is opened, the flow velocity through the three valve seats gradually decreases, and the scouring also gradually weakens. Elastic elements 7, which are butterfly springs, are also provided between valve seats I4 and II5, and between valve seats II5 and III6, respectively, to provide initial sealing pre-tightening pressure and compensate for machining errors of the three metal sealing surfaces of the valve disc 3. These elastic elements ensure complete contact between the sealing surfaces of the valve seats and the valve core in the initial position and provide the initial sealing pressure. The valve disc 3 also has three metal sealing cone surfaces at its end, which are respectively adapted to valve seats I4, II5, and III6. The three metal sealing cone surfaces on the valve disc 3 are respectively sealed to valve seats I4, II5, and III6. A cylinder liner 8 is also provided on the outer circular end face of the valve seat hole. The cylinder liner 8 is limited to valve seats I4, II5, and III6 to prevent them from coming out of the valve seat hole.

[0025] The valve seats I4, II5, and III6 have axial movement between the limiting position of the cylinder liner 8 and the valve seat bore platform. When the valve disc closes, it pushes valve seat I into contact with the valve body's bottom bore platform, generating an initial sealing pressure between valve seat I and the valve disc sealing pair, thus achieving a seal. At this time, the ring between the outer circle G of the valve seat and the inner hole A of the valve seat is pushed upwards by the medium pressure, generating an upward force. The greater the medium pressure, the greater the force acting on this ring, and the greater the sealing pressure generated on the valve disc and valve seat I sealing pair, resulting in a better sealing effect. Therefore, the sealing effect of valve seat I and the valve disc, compared to conventionally designed sealing structures, has a pressure self-sealing effect. When leakage occurs after long-term use of the valve seat I and valve disc sealing surface, the medium enters the sealing pair between valve seat II and the valve disc. At this time, due to the preload of the disc spring, a pressure is generated, forming an initial seal. The ring formed between the outer circle G of the valve seat and the inner hole B of the valve seat II, under the push of the medium pressure, generates an upward force pushing valve seat II, increasing the sealing pressure and promoting sealing, which is also a pressure self-sealing effect. When valve seat II fails after prolonged use, the medium enters between valve seat III and the valve disc sealing pair. Under the preload of the disc spring, valve seat III achieves initial sealing, and the force acting on the valve seat III ring also achieves a self-sealing effect. The individual sealing performance of each valve seat improves with higher pressure, preventing erosion and particle wear caused by minor leaks, significantly extending the sealing life of each individual valve seat. The sealing performance of the three valve seats only fails after each seat gradually deteriorates. Therefore, the valve seat sealing performance of this valve is at least three times longer than that of ordinary valves. Furthermore, the pressure self-sealing capability of the valve seats makes it particularly suitable for high-pressure media, preventing erosion and wear caused by minor leaks between the sealing surfaces. Therefore, its sealing life is more than ten times that of ordinary valves.

[0026] The outer circumferential surfaces of valve seats I4, II5, and III6 are sealed with the inner wall of the valve seat hole by O-rings 11.

[0027] The valve disc 3 is designed with an increased height. The valve disc 3 has an annular groove U33 in the middle and a shoulder structure 31 above the annular groove U. The cylinder liner 8 has an extended part 81 at the top and an annular groove V85 on the inner circular surface of the cylinder liner 8. The groove width, groove depth and groove position are designed to serve as the medium channel after opening.

[0028] The extended portion 81 of the cylinder liner 8 is provided with a throttling orifice 82. The lower end face of the extended portion 81 is flush with the lower end face of the shoulder structure 31 when the valve is closed. The distance from the throttling orifice 82 to the lower end face of the extended portion 81 is M. The stroke of the valve seats I 4, II 5, and III 6 completely separating from the metal sealing surfaces on the valve disc 3 is N. The distance M is greater than the stroke N. This ensures that the M dimension after installation is greater than the N dimension, guaranteeing that the valve disc sealing surface and the valve seat sealing surface are fully separated after the valve is effectively opened. This completely avoids gap erosion and throttling erosion, and prevents cavitation and impact of high-speed sand-containing fluid on the sealing surface. M being greater than N also effectively ensures that the three sealing surfaces of the valve disc are not eroded by gaps at the moment of effective opening. During the initial opening stage of the valve, there is a very small flow process that is not used for adjusting the flow range (zero-point empty stroke). This process is the M stroke. Only after the M stroke is it used for adjusting the flow range. These will be explained in the instruction manual and marked on the start indicator. When the opening height reaches M, the valve is in an effective opening state for regulating flow. The valve disc annular groove and the throttling orifice for flow regulation in the cylinder liner are at the same height, gradually increasing to achieve effective flow regulation. At this point, adverse effects such as maximum flow velocity, pressure drop, flashing, and cavitation all occur. Hardening treatment of the valve disc annular groove and corresponding parts of the cylinder liner can largely prevent damage. Even if pitting or small water flow grooves are created at this point, it will not affect the regulating function of this manually adjustable flow valve. It ensures that the sealing surfaces of the valve seat and valve disc remain undamaged for a long time, guaranteeing the reliability of the sealing performance when closed. If the valve is used at a large opening or fully open (H > F or D > E), it will not cause damage to any part. With the reliable guarantee of its three valve seats and triple metal seals, its service life will be more than ten times that of ordinary valves.

[0029] The outer circular surface of the shoulder structure 31 slides and engages with the inner wall of the extended portion 81 of the cylinder liner 8 to adjust the opening size of the guide hole 82. The throttling function is assisted by the shoulder structure 31 in the middle of the valve disc. The opening size between the outer circular surface of the shoulder 31 and the guide hole of the cylinder liner is adjusted. When in the adjustment state, erosion, cavitation, particle impact pits, etc., only occur in this area. The shoulder and groove areas in this area have been hardened, and the cylinder liner throttling hole and surrounding areas have also been hardened. Its wear resistance is very high. Even if there is some damage after a long time, it will not affect the adjustment accuracy of this manually adjustable valve, but its sealing performance when closed will never be affected, ensuring the long-term use of the valve.

[0030] Two layers of four-ring 83 are provided between the cylinder liner 8 and the valve body 1. The four-ring 83 has oblique holes 84 at angle α. The oblique holes 84 between the two layers of four-ring 83 are installed in opposite directions and are staggered. The valve body has small grooves for fixing the four-ring by stamping or rolling to ensure that the four-ring will not be rotated by the medium after installation, and to ensure that the position of its guide hole remains unchanged. During installation, the oblique holes of the first layer of four-ring valves are misaligned with the upper throttling orifice of the cylinder liner. The oblique holes of the upper four-ring valves are then installed at the opposite angle and misaligned with the oblique holes of the lower four-ring valves. This misalignment of the medium exiting through the throttling orifice with the upper and lower four-ring valves creates a labyrinth effect when the valve is fully open or at a large opening. This results in a significant drop in flow rate at the outlet of the lower four-ring valve's oblique hole, causing the highest flow velocity or potential cavitation damage to occur at this point. This effectively protects the seal between the valve disc and seat, as well as the contact area between the cylinder liner's throttling orifice and the valve disc / cylinder liner's throttling orifice. The double-layer four-ring valve structure with reverse oblique holes primarily ensures that the area of ​​sudden change in flow area at a large valve opening is located at the oblique hole of the lower four-ring valve. The abrupt change in flow area of ​​the throttling or regulating valve is where erosion, cavitation, and damage occur. This structure provides good protection for the throttling orifice area and the valve disc / seat sealing area. This also greatly ensures a long valve lifespan.

[0031] The valve disc 3 is provided with a pressure hole 32 for pressurizing the middle cavity. A cylinder ring 9 is located in the upper middle cavity of the cylinder sleeve 8. The inner diameter of the cylinder ring 9 is the same as the inner diameter of the valve seat II 5. Together with the pressure hole 32, they form a self-balancing structure that can balance the upward pressure of the medium and reduce the switching torque. High-pressure shut-off valves, especially those with low inlet and high outlet, have particularly large torque. They employ a self-balancing design, with a pressure hole on the valve disc for pressurizing the middle cavity. A cylinder ring is located at the upper end of the cylinder sleeve, and its inner diameter is approximately the same as the inner diameter of the valve seat II. This balances the upward pressure of the medium, reduces the switching torque, and facilitates easy operation.

[0032] This valve's flow regulation function does not rely on the gap size between the valve seat and valve disc sealing surfaces to adjust the flow rate. It is only used for sealing when closed. Furthermore, it features three valve seats and three pairs of sealing surfaces. If the sealing surface corresponding to valve seat I fails after prolonged use, the sealing surface of valve seat II will then participate in the sealing function. Similarly, if the sealing surface of valve seat II fails after prolonged use, the sealing surface of valve seat III will then participate in the sealing function. This provides three layers of protection for a complete seal, resulting in a lifespan more than three times that of a single valve seat. If there is a small leak in the first layer of valve seat sealing surfaces, the second layer of valve seat will seal very easily because the pressure entering the second layer is significantly reduced, making sealing much easier. Furthermore, if the second layer of valve seat leaks over time, the pressure entering the third layer of valve seat will be even lower, further ensuring a secure seal. Therefore, the three-seat configuration not only has a long lifespan, but the three layers of sealing also increase the sealing life tenfold. When closed, the absence of even small leaks between the valve seat and valve disc sealing surfaces completely avoids high-speed fluid cavitation and particle erosion damage to the sealing surface caused by gap leaks, thus greatly increasing the valve's service life.

[0033] The main advantage of this valve is that the regulating and throttling section is located far from the metal conical sealing area of ​​the switching function. The throttling section can be hardened independently, and minor erosion or damage during use is permissible without affecting the regulating function. The medium downstream of the regulating section needs to pass through a labyrinthine pressure reduction and deceleration process formed by the misalignment of the double four-ring oblique holes and the misalignment of the upper four-ring oblique holes with the throttling hole. This further reduces erosion and damage to the regulating and throttling section, extending its service life. The main functions of this type of valve are sealing and throttling. Its structural design provides complete and sufficient protection for the sealing function, and it also has a triple seal; the main seal only fails after all three fail. The throttling and sealing areas are far apart, ensuring better sealing reliability. Downstream of the throttling area, there is also a labyrinthine pressure reduction protection function, further protecting the throttling area and components. Therefore, the overall service life of this valve is very long, and its cost-effectiveness is also very high.

[0034] Please note to all technical personnel: Although the present invention has been described according to the specific embodiments above, the inventive concept of the present invention is not limited to this invention. Any modifications that utilize the inventive concept will be included within the scope of patent protection of this patent.

[0035] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. An oilfield water injection throttling and regulating shut-off valve, comprising a valve body (1), wherein a valve stem (2) is provided inside the valve body (1), and a valve disc (3) is provided at the end of the valve stem (2), characterized in that, The valve body (1) has three independent valve seats I (4), II (5), and III (6) arranged sequentially from bottom to top in the valve seat hole. Each of the valve seats I (4), II (5), and III has a valve seat sealing surface. The flow inner diameter of each of the valve seats I (4), II (5), and III (6) increases progressively. Elastic elements (7) are also provided between valve seats I (4) and II (5), and between valve seats II (5) and III (6) to provide pre-tightening force for initial sealing pre-tightening pressure and to compensate for machining errors of the three metal sealing surfaces of the valve disc (3). The end of the valve disc (3) is also provided with three metal seals that are adapted to valve seats I (4), II (5), and III (6) respectively. On the valve disc (3), the three metal sealing surfaces are respectively sealed and fitted with valve seat I (4), valve seat II (5), and valve seat III (6). A cylinder sleeve (8) is also provided on the outer circular end face of the valve seat hole. The cylinder sleeve (8) and valve seat I (4), valve seat II (5), and valve seat III (6) are limited and fitted to ensure that valve seat I (4), valve seat II (5), and valve seat III (6) do not come out in the valve seat hole. Valve seat I (4), valve seat II (5), and valve seat III (6) have axial movement between the cylinder sleeve (8) and the valve seat hole platform. There are certain gaps between valve seat I (4) and valve seat II (5), between valve seat II (5) and valve seat III (6), and between valve seat III (6) and the lower end of cylinder sleeve (8).

2. The oilfield water injection throttling regulating shut-off valve according to claim 1, characterized in that, The outer circumferential surfaces of valve seats I (4), II (5), and III (6) are sealed with the inner wall of the valve seat hole by O-rings (11).

3. The oilfield water injection throttling regulating shut-off valve according to claim 1, characterized in that, The valve disc (3) is designed to be heightened. The valve disc (3) has an annular groove U (33) in the middle. The annular groove U has a shoulder structure (31) above it. The cylinder liner (8) has an extended part (81) at the top. The cylinder liner (8) has an annular groove V (85) on its inner surface. The valve disc (3) has a shoulder (34) below the annular groove U. The length of the shoulder (34) is N.

4. The oilfield water injection throttling regulating shut-off valve according to claim 3, characterized in that, The cylinder liner (8) has an extension (81) with a throttle hole (82). The lower end face of the extension (81) is flush with the lower end face of the shoulder structure (31) when the valve is closed. The distance from the throttle hole (82) to the lower end face of the extension (81) is M, and the distance M is greater than the length of the shoulder (34) by N.

5. The oilfield water injection throttling regulating shut-off valve according to claim 3, characterized in that, The outer circular surface of the shoulder structure slides and engages with the inner wall of the extended portion (81) of the cylinder liner (8) to adjust the opening size of the throttle orifice (82).

6. The oilfield water injection throttling regulating shut-off valve according to claim 1, characterized in that, Two layers of four-ring (83) are provided between the cylinder liner (8) and the valve body (1). An inclined hole (84) at angle a is provided on the four-ring (83). The inclined holes (84) between the two layers of four-ring (83) are installed in opposite directions and the inclined hole (84) of the upper four-ring is installed in opposite directions with the cylinder liner throttle hole (82).

7. The oilfield water injection throttling regulating shut-off valve according to claim 1, characterized in that, The valve disc (3) is provided with a pressure hole (32) for pressurizing into the middle cavity. The cylinder ring (9) is provided in the upper middle cavity of the cylinder sleeve (8). The inner diameter of the cylinder ring (9) is consistent with the inner diameter of the valve seat II (5). Together with the pressure hole (32), they form a self-balancing structure that can balance the upward pressure of the medium and reduce the switching torque.

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