Adjustable chemical injection valve

Abstract

The adjustable chemical injection valve comprises a lower valve body assembly, a middle valve body assembly, an upper valve body assembly, an adjusting connector and a conversion connector which are sequentially arranged along the same axis, the pre-tightening force of a third elastic element can be flexibly adjusted by controlling the thread meshing length L, and therefore the opening pressure of the chemical injection valve can be adjusted. Therefore, the opening pressure value can be flexibly set according to specific well conditions; secondly, the sealing reliability is improved by arranging a three-stage redundant sealing structure; the dependence on a control pipeline is avoided, the medicament is conveyed to a required underground position by adopting the annulus injection channel matched with the complex well condition, the flowing path of the medicament in the annulus is smoother and is hardly influenced by the well condition, the medicament conveying efficiency can be greatly improved, and the medicament conveying cost is reduced. The injection valve has the advantages of adaptive opening pressure adjustment, repeated use, good sealing effect, no dependence on a disposable rupture disk and the like.

Description

Technical Field

[0001] This utility model relates to the technical field of industrial oil and gas well chemical injection devices, specifically an adjustable chemical injection valve. Background Technology

[0002] In oil and gas extraction, corrosive gases such as hydrogen sulfide and carbon dioxide can corrode tubing and downhole tools. Asphaltenes and gums in crude oil can easily precipitate and clog tubing, and formation water ions can easily form scale under high temperature and pressure. These problems all require the injection of chemicals to solve. Chemical injection valves are key tools for injecting anti-corrosion, anti-scaling, and unclogging agents downhole. However, chemical injection valves have the following drawbacks: First, existing chemical injection valves require setting the opening pressure based on a disposable rupture disc. This disposable rupture disc is a critical safety device used in chemical injection valves, functioning similarly to a one-time "pressure fuse." When the downhole annular pressure reaches a preset critical value, the disposable rupture disc ruptures instantly, opening the injection channel. This disposable nature means that existing chemical injection valves cannot precisely adjust the opening pressure according to changes in well depth, temperature, and pressure, resulting in either insufficient injection of the agent, rendering it ineffective, or excessive injection, causing waste and environmental pollution. Second, after the disposable rupture disc ruptures, the entire valve must be replaced, and fragments from the ruptured disc can easily clog the injection channel. Furthermore, existing chemical injection valves rely on control lines to inject chemicals. In complex well conditions such as well deviations and obstacles, it is difficult to accurately deliver chemicals to the target location using control lines, resulting in low delivery efficiency. Therefore, the industry urgently needs a new type of chemical injection valve that can adaptively adjust the opening pressure, is reusable, has good sealing performance, and does not rely on disposable rupture discs. Utility Model Content

[0003] To solve the above problems, this utility model provides an adjustable chemical injection valve, including a lower valve body assembly, a middle valve body assembly, an upper valve body assembly, an adjustment joint, and a conversion joint arranged sequentially along the same axis;

[0004] The lower valve body assembly includes a first sleeve and a first check valve component. The lower end of the first sleeve is provided with an external thread that can be connected to the lower connector. The first check valve component is composed of a first valve core and a first elastic element. The first valve core can reciprocate along the axis in the inner cavity of the first sleeve.

[0005] The valve body assembly includes a second sleeve and a second one-way valve component. The lower end of the second sleeve is threadedly connected to the upper end of the first sleeve. The second one-way valve component consists of a second valve core and a second elastic element. The second valve core can reciprocate along the axis in the inner cavity of the second sleeve. The first valve core contacts the first gasket on the second sleeve under the action of the first elastic element to form a first sealing surface.

[0006] The upper valve body assembly includes a third sleeve and a third check valve component. The lower end of the third sleeve is threadedly connected to the upper end of the second sleeve. The third check valve component is composed of a third valve core and a third elastic element. The third valve core can reciprocate along the axis in the inner cavity of the third sleeve. Under the action of the second elastic element, the second valve core contacts the second gasket on the third sleeve to form a second sealing surface.

[0007] The lower end of the adjusting joint is threaded to the upper end of the third sleeve. The pre-compression of the third elastic element is adjusted by changing the thread engagement length L between the adjusting joint and the third sleeve, thereby setting the opening pressure of the chemical injection valve. The third valve core forms a third sealing surface with the adjusting joint under the action of the third elastic element. The lower end of the conversion joint is threaded to the upper end of the adjusting joint. The upper end of the conversion joint is provided with an internal thread that connects to the chemical injection pipeline.

[0008] The first, second, and third check valve components open in the same direction to allow the chemical fluid to flow unidirectionally from the third check valve component to the first check valve component.

[0009] Preferably, the third elastic element is a helical compression spring, and the stiffness and pre-compression of the helical compression spring correspond to the opening pressure gradient of the third one-way valve component.

[0010] Preferably, the first valve core includes a first sealing surface and a first guide tail post, the first guide tail post being in clearance fit with the guide hole of the inner cavity of the first sleeve; the second valve core includes a second sealing surface and a second guide tail post, the second guide tail post being in clearance fit with the guide hole of the inner cavity of the second sleeve; and the third valve core includes a third sealing surface and a third guide tail post, the third guide tail post being in clearance fit with the guide hole of the inner cavity of the third sleeve.

[0011] Preferably, the lower end of the second sleeve and the upper end of the first sleeve are further locked together by a first anti-loosening fastener.

[0012] Preferably, the lower end of the third sleeve and the upper end of the second sleeve are further locked together by a second anti-loosening fastener.

[0013] Preferably, the threaded connection between the adjusting joint and the third sleeve is further locked by a third anti-loosening fastener.

[0014] Preferably, the minimum flow cross-sectional area of ​​the flow channel inside the regulating joint is less than the effective flow cross-sectional area when the third valve core is fully open.

[0015] Preferably, the mating surfaces of the second sleeve and the first sleeve, the third sleeve and the second sleeve, and the adjusting joint and the third sleeve are all provided with sealing components. The sealing components include sealing rings and limiting rings. The limiting rings are located on both sides of the sealing rings. The adjusting joint, the third sleeve, and the second sleeve are all provided with sealing grooves. The sealing components are placed in the corresponding sealing grooves and coated with lubricating medium to achieve sealing.

[0016] Preferably, the thread engagement length L is adjustable in the range of 5-50mm, corresponding to an opening pressure range of 5-50MPa.

[0017] Preferably, it is installed on an eccentric support cylinder, and the injection of the agent is achieved by annular pressure.

[0018] The beneficial effects are as follows: The adjustable chemical injection valve designed in this application adjusts the preload of the third elastic element by controlling the thread engagement length L, thereby adjusting the opening pressure of the chemical injection valve. This allows for flexible setting of the opening pressure value according to specific well conditions. Secondly, this application also features a three-stage redundant sealing structure: the first valve core contacts the gasket on the second sleeve to form a first sealing surface, the second valve core contacts the gasket on the third sleeve to form a second sealing surface, and the third valve core contacts the adjusting joint to form a third sealing surface, thereby improving sealing reliability. In addition, this application eliminates the dependence on control pipelines and uses an annular injection channel adapted to complex well conditions to deliver the agent to the required location downhole. The flow path of the agent within the annulus is smoother and almost unaffected by well conditions, which can greatly improve the agent delivery efficiency. Attached Figure Description

[0019] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0020] Figure 1 A schematic diagram of the overall structure of an adjustable chemical injection valve assembled on an eccentric support.

[0021] Figure 2 A cross-sectional structural diagram of an adjustable chemical injection valve assembled on an eccentric support.

[0022] Figure 3 Cross-sectional view of an adjustable chemical injection valve;

[0023] Figure 4 This is a schematic diagram of the explosion structure of an adjustable chemical injection valve.

[0024] Figure 5 This is a schematic diagram of the first valve core structure;

[0025] Figure 6 This is a schematic diagram of the third valve core structure;

[0026] In the picture:

[0027] 1. Eccentric support sleeve;

[0028] 2. Chemical injection pipeline;

[0029] 3. Adjustable chemical injection valve;

[0030] 31. Lower valve body assembly; 311. First sleeve; 3111. First anti-loosening fastener; 312. First one-way valve component; 3121. First valve core; 31211. First sealing surface; 31212. First guide tail post; 3122. First elastic element; 31221. First spring washer;

[0031] 32. Middle valve body assembly; 321. Second sleeve; 3211. First gasket; 3212. Second anti-loosening fastener; 322. Second check valve component; 3221. Second valve core; 3222. Second elastic element; 32221. Second spring washer;

[0032] 33. Upper valve body assembly; 331. Third sleeve; 3311. Second gasket; 3312. Third anti-loosening fastener; 332. Third check valve component; 3321. Third valve core; 33211. Third sealing surface; 33212. Third guide tail post; 3322. Third elastic element;

[0033] 34. Adjust the connector;

[0034] 35. Adapter connector;

[0035] 36. Sealing assembly; 361. Sealing ring; 362. Limiting ring;

[0036] 4. Lower connector. Detailed Implementation

[0037] The following drawings will disclose several embodiments of this utility model. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details should not be used to limit this utility model. That is, in some embodiments of this utility model, these practical details are not essential. In addition, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0038] It should be noted that all directional indicators in this utility model embodiment, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indicator will also change accordingly.

[0039] Furthermore, in this utility model, the use of terms such as "first" and "second" is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the utility model. They are merely used to distinguish components or operations described with the same technical terms and should not be construed as indicating or implying their relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0040] Example

[0041] Please see Figure 1 and Figure 2 , Figure 1 A schematic diagram of the overall structure of an adjustable chemical injection valve assembled on an eccentric support. Figure 2 This is a cross-sectional structural diagram of an adjustable chemical injection valve assembled on an eccentric support. This embodiment provides an adjustable chemical injection valve 3, which has an overall cylindrical structure and is installed on an eccentric support 1. The eccentric support 1 is connected to the tubing string. Chemical injection is achieved through annular pressure testing. Specifically, annular pressure testing refers to a working method where the operator starts a pump on the surface and applies pressure to the annular space between the tubing and casing to drive the chemical injection valve to open and inject the chemical into the target formation. Compared to control line injection, annular pressure testing reduces chemical flow restrictions and improves chemical delivery efficiency under complex well conditions.

[0042] See also Figure 2 Combined again Figure 3 , Figure 3 This is a cross-sectional view of an adjustable chemical injection valve. The adjustable chemical injection valve 3 includes a lower valve body assembly 31, a middle valve body assembly 32, an upper valve body assembly 33, an adjusting connector 34, and a conversion connector 35 arranged sequentially along the same axis.

[0043] See also Figure 3 Combined again Figure 4 , Figure 4 This is a schematic diagram of the exploded structure of an adjustable chemical injection valve. The lower valve body assembly 31 includes a first sleeve 311 and a first one-way valve component 312, both made of corrosion-resistant alloy steel to resist corrosion from the external environment. The lower end of the first sleeve 311 has an external thread that can connect to the lower connector 4. The first one-way valve component 312 consists of a first valve core 3121 and a first elastic element 3122. Under the action of the first elastic element 3122, the first valve core 3121 reciprocates along the axis within the inner cavity of the first sleeve 311. Please refer to [link / reference]. Figure 5 , Figure 5 This is a schematic diagram of the first valve core structure. The first valve core 3121 includes a first sealing surface 31211 and a first guide post 31212. The first guide post 31212 has a grid-like hollow columnar structure. The first sealing surface 31211 is a hard alloy spherical surface with a cone angle of 10~25° to improve sealing accuracy and significantly enhance wear resistance and impact resistance. The first sealing surface 31211 is also provided with a spiral guide groove with a groove depth of 30~50μm and a pitch of 0.5~1.5mm to use fluid kinetic energy to flush away deposits on the surface of the first valve core 3121 and reduce the risk of jamming. The clearance fit between the first guide post 31212 and the guide hole in the inner cavity of the first sleeve 311 can ensure the coaxiality of the first valve core 3121 when it reciprocates along the axis, avoiding sealing failure due to uneven wear. The first elastic element 3122 is a helical compression spring. One end of the first elastic element 3122 is placed inside the first guide tail post 31212. The end of the first elastic element 3122 away from the first valve core 3121 is also fitted with a first spring washer 31221. The first spring washer 31221 can prevent the first elastic element 3122 from radially shifting during reciprocating motion, ensuring the stability of the elastic force output.

[0044] See also Figure 4The valve body assembly 32 includes a second sleeve 321 and a second one-way valve component 322, both made of corrosion-resistant alloy steel to resist corrosion from the external environment. The lower end of the second sleeve 321 extends into the first sleeve 311 and is threadedly connected to the upper end of the first sleeve 311. The lower end of the second sleeve 321 and the upper end of the first sleeve 311 are further locked by a first anti-loosening fastener 3111. In this embodiment, the first anti-loosening fastener 3111 is specifically a set screw. The first anti-loosening fastener 3111 passes radially through the second sleeve 321 and presses against the outer periphery of the third sleeve 331 to prevent the threads from loosening. A sealing assembly 36 is provided on the mating surface between the second sleeve 321 and the first sleeve 311. The sealing assembly 36 includes a sealing ring 361 and a limiting ring 362. The limiting ring 362 is located on both sides of the sealing ring 361. A sealing groove is provided on the second sleeve 321. The sealing assembly 36 is placed in the corresponding sealing groove and coated with a lubricating medium to achieve a seal. The lower end of the second sleeve 321 is also provided with a first gasket 3211. The first valve core 3121 contacts the first gasket 3211 on the second sleeve 321 under the action of the first elastic element 3122 to form a first sealing surface 31211. The second one-way valve component 322 consists of a second valve core 3221 and a second elastic element 3222. Under the action of the second elastic element 3222, the second valve core 3221 reciprocates along the axis in the inner cavity of the second sleeve 321. The second valve core 3221 has the same structure as the first valve core 3121, including a second sealing surface and a second guide tail post, and is therefore not shown in the figure. The second sealing surface is a hard alloy spherical surface with a cone angle of 10~25° to improve sealing accuracy and significantly enhance wear resistance and impact resistance. The second sealing surface is also provided with a spiral guide groove with a groove depth of 30~50μm and a pitch of 0.5~1.5mm to use fluid kinetic energy to flush the deposits on the surface of the second valve core 3221 and reduce the risk of jamming. The clearance fit between the second guide tail post and the guide hole in the inner cavity of the second sleeve 321 can ensure the coaxiality of the second valve core 3221 when it reciprocates along the axis, and avoid sealing failure due to uneven wear. The second elastic element 3222 is a helical compression spring. One end of the second elastic element 3222 is placed inside the second guide tail post. The end of the second elastic element 3222 away from the second valve core 3221 is also fitted with a second spring washer 32221. The second spring washer 32221 can prevent the second elastic element 3222 from radially shifting during reciprocating motion, ensuring the stability of the elastic force output.

[0045] The upper valve body assembly 33 includes a third sleeve 331 and a third one-way valve component 332, both made of corrosion-resistant alloy steel to resist corrosion from the external environment. The lower end of the third sleeve 331 extends into the second sleeve 321 and is threadedly connected to the upper end of the second sleeve 321. The lower end of the third sleeve 331 and the second sleeve 321 are further locked by a second anti-loosening fastener 3212. In this embodiment, the second anti-loosening fastener 3212 is specifically a set screw. The second anti-loosening fastener 3212 passes radially through the first sleeve 311 and presses against the outer circumference of the second sleeve 321 to prevent the threads from loosening. A sealing assembly 36 is provided on the mating surface between the third sleeve 331 and the second sleeve 321. The sealing assembly 36 includes a sealing ring 361 and a limiting ring 362. The limiting ring 362 is located on both sides of the sealing ring 361. A sealing groove is provided on the third sleeve 331. The sealing assembly 36 is placed in the corresponding sealing groove and coated with a lubricating medium to achieve a seal. The lower end of the third sleeve 331 is also provided with a second gasket 3311. Under the action of the second elastic element 3222, the second valve core 3221 contacts the second gasket 3311 on the third sleeve 331 to form a second sealing surface. The third one-way valve component 332 is composed of the third valve core 3321 and the third elastic element 3322. Under the action of the third elastic element 3322, the third valve core 3321 reciprocates along the axis within the inner cavity of the third sleeve 331. Please refer to [link / reference]. Figure 6 , Figure 6 This is a schematic diagram of the third valve core structure. The third valve core 3321 includes a third sealing surface 33211 and a third guide post 33212. The third guide post 33212 is a hollow cylindrical structure. The third sealing surface 33211 has multiple guide holes communicating with the third guide post 33212. The clearance fit between the third guide post 33212 and the guide hole in the inner cavity of the third sleeve 331 ensures the coaxiality of the third valve core 3321 when it reciprocates along the axis, avoiding sealing failure due to uneven wear. The third elastic element 3322 is a helical compression spring. One end of the third elastic element 3322 is sleeved on the third guide post 33212. The stiffness parameters and pre-compression amount of the third elastic element 3322 are precisely calculated to accurately match the opening pressure gradient of the third one-way valve component 332, thus achieving adaptive pressure control under different working conditions and ensuring precise control of the drug injection volume. It is worth noting that the opening directions of the first one-way valve component 312, the second one-way valve component 322, and the third one-way valve component 332 are consistent, so as to allow the chemical fluid to flow unidirectionally from the third one-way valve component to the first one-way valve component.

[0046] The lower end of the adjusting joint 34 is threadedly connected to the upper end of the third sleeve 331. The adjusting joint 34 and the third sleeve 331 are further locked by a third anti-loosening fastener 3312. In this embodiment, the third anti-loosening fastener 3312 is specifically a set screw. The third anti-loosening fastener 3312 passes radially through the third sleeve 331 and presses against the outer periphery of the adjusting joint 34 to prevent the threads from loosening. A sealing component 36 is provided on the mating surface of the adjusting joint 34 and the third sleeve 331. The sealing component 36 includes a sealing ring 361 and a limiting ring 362. The limiting ring 362 is located on both sides of the sealing ring 361. The adjusting joint 34 is provided with a sealing groove. The sealing component 36 is placed in the corresponding sealing groove and coated with a lubricating medium to achieve a seal. The pre-compression of the third elastic element 3322 is adjusted by changing the thread engagement length L between the adjusting connector 34 and the third sleeve 331, thereby setting the opening pressure of the chemical injection valve. The thread engagement length L is adjustable in the range of 5-50 mm, corresponding to an opening pressure range of 5-50 MPa. Under the action of the third elastic element 3322, the third valve core 3321 forms a third sealing surface 33211 with the adjusting connector 34 to provide a third-level sealing guarantee under reverse pressure. The lower end of the conversion connector 35 is threadedly connected to the upper end of the adjusting connector 34, and the upper end of the conversion connector 35 is provided with an internal thread that mates with the chemical injection pipeline 2. The minimum flow cross-sectional area of ​​the flow channel inside the adjusting connector 34 is smaller than the effective flow cross-sectional area when the third valve core 3321 is fully open, so as to avoid the flow interception phenomenon under the opening pressure and reduce the fluid erosion effect.

[0047] In use, the opening pressure value is set according to the well conditions, the thread engagement length L is adjusted, the chemical injection valve is installed in the eccentric support 1, and pressure is applied from the annulus. The pressure pushes open the third valve core 3321 and compresses the third elastic element 3322. The chemical agent enters from the chemical injection line 2, and then enters the third guide tail column 33212 through the flow channel inside the adjusting joint 34 and the guide hole of the third valve core 3321 in sequence. After that, it continues to flow along the guide hole inside the third sleeve 331 and pushes open the second valve core 3221 and compresses the second elastic element 3222. The chemical agent continues to flow along the guide hole inside the second sleeve 321 and pushes open the first valve core 3121 and compresses the first elastic element 3122. Finally, it flows from the guide hole inside the first sleeve 311 into the tubing to remove the fouling in the tubing. When the pressure to the annulus is stopped, the first valve core 3121, the second valve core 3221 and the third valve core 3321 form a three-stage redundant sealing structure with the gasket on the second sleeve 321, the gasket on the third sleeve 331 and the adjusting joint 34 under the action of the elastic element, respectively, so that the annulus is isolated from the oil pipe.

[0048] In summary, the adjustable chemical injection valve 3 designed in this application can precisely adjust the preload of the third elastic element 3322 by controlling the thread engagement length L, thus allowing for flexible setting of the chemical injection valve opening pressure value according to specific well conditions. It only opens when the wellhead pressure reaches the set value, facilitating monitoring and observation. Different opening pressure values ​​can be set for different well formation requirements, enabling layered control and adjustment of the opening pressure without needing to pull out the tubing. Furthermore, this application also features a three-stage redundant sealing structure, where the first valve core 3121 contacts the gasket on the second sleeve 321 to form the first sealing surface. 31211, the second valve core 3221 and the gasket on the third sleeve 331 contact to form a second sealing surface, and the third valve core 3321 and the adjusting joint 34 form a third sealing surface 33211 to improve sealing reliability; compared with chemical injection valves with rupture discs, this injection valve can be reused multiple times and has a lower cost; in addition, this application eliminates the dependence on control pipelines and uses an annular injection channel adapted to complex well conditions to deliver the agent to the required location downhole. The path of the agent flow in the annulus is smoother and almost unaffected by well conditions, which can greatly improve the agent delivery efficiency.

[0049] The above are merely embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. An adjustable chemical injection valve characterized by, It includes a lower valve body assembly, a middle valve body assembly, an upper valve body assembly, an adjusting joint, and a conversion joint arranged sequentially along the same axis; The lower valve body assembly includes a first sleeve and a first one-way valve component. The lower end of the first sleeve is provided with an external thread that can be connected to the lower connector. The first one-way valve component is composed of a first valve core and a first elastic element. The first valve core can reciprocate along the axis in the inner cavity of the first sleeve. The valve body assembly includes a second sleeve and a second one-way valve component. The lower end of the second sleeve is threadedly connected to the upper end of the first sleeve. The second one-way valve component is composed of a second valve core and a second elastic element. The second valve core can reciprocate along the axis in the inner cavity of the second sleeve. Under the action of the first elastic element, the first valve core contacts the first gasket on the second sleeve to form a first sealing surface. The upper valve body assembly includes a third sleeve and a third one-way valve component. The lower end of the third sleeve is threadedly connected to the upper end of the second sleeve. The third one-way valve component is composed of a third valve core and a third elastic element. The third valve core can reciprocate along the axis in the inner cavity of the third sleeve. Under the action of the second elastic element, the second valve core contacts the second gasket on the third sleeve to form a second sealing surface. The lower end of the adjusting connector is threadedly connected to the upper end of the third sleeve. By changing the thread engagement length L between the adjusting connector and the third sleeve, the pre-compression of the third elastic element is adjusted, thereby setting the opening pressure of the chemical injection valve. The third valve core forms a third sealing surface with the adjusting connector under the action of the third elastic element. The lower end of the conversion connector is threadedly connected to the upper end of the adjusting connector, and the upper end of the conversion connector is provided with an internal thread portion that mates with the chemical injection pipeline. The first, second, and third check valve components open in the same direction to allow the chemical fluid to flow unidirectionally from the third check valve component to the first check valve component.

2. The adjustable chemical injection valve of claim 1, wherein, The third elastic element is a helical compression spring, and the stiffness and pre-compression of the helical compression spring correspond to the opening pressure gradient of the third one-way valve component.

3. The adjustable chemical injection valve of claim 1, wherein, The first valve core includes a first sealing surface and a first guide tail post, the first guide tail post being in clearance fit with the guide hole of the inner cavity of the first sleeve; the second valve core includes a second sealing surface and a second guide tail post, the second guide tail post being in clearance fit with the guide hole of the inner cavity of the second sleeve; the third valve core includes a third sealing surface and a third guide tail post, the third guide tail post being in clearance fit with the guide hole of the inner cavity of the third sleeve.

4. The adjustable chemical injection valve of claim 1, wherein, The lower end of the second sleeve is further locked to the upper end of the first sleeve by a first anti-loosening fastener.

5. The adjustable chemical injection valve of claim 1, wherein, The lower end of the third sleeve and the upper end of the second sleeve are further locked together by a second anti-loosening fastener.

6. The adjustable chemical injection valve of claim 1, wherein, The adjusting joint and the third sleeve are further locked together by a third anti-loosening fastener.

7. The adjustable chemical injection valve of claim 1, wherein, The minimum flow cross-sectional area of ​​the flow channel inside the regulating joint is less than the effective flow cross-sectional area when the third valve core is fully open.

8. The adjustable chemical injection valve of claim 1, wherein, The mating surfaces of the second sleeve and the first sleeve, the third sleeve and the second sleeve, and the adjusting joint and the third sleeve are all provided with sealing components. Each sealing component includes a sealing ring and a limiting ring. The limiting ring is located on both sides of the sealing ring. Each adjusting joint, the third sleeve, and the second sleeve are provided with sealing grooves. The sealing components are placed in the corresponding sealing grooves and coated with a lubricating medium to achieve sealing.

9. The adjustable chemical injection valve of claim 1, wherein, The thread engagement length L is adjustable in the range of 5-50mm, corresponding to an opening pressure range of 5-50MPa.

10. The adjustable chemical injection valve of claim 1, wherein, It is installed on an eccentric support and the injection of the agent is achieved through annular pressure.

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