Fluid injection valve

Abstract

The utility model provides a kind of fluid injection valve, including valve body, valve stem, pressure regulating assembly and injection head, the injection head bottom is equipped with liquid outlet passage, the valve body, injection head and pressure regulating assembly and the side wall of valve stem form inner cavity, the valve stem is passed through the valve body and its lower end and the bottom of injection head condition abuts, the valve stem's isolation boss will be divided into upper and lower chambers, upper chamber pressure is maintained by pressure regulating assembly, lower chamber is connected with dosing liquid inlet pipeline, the dosing liquid inlet pipeline is connected with bypass return pipeline with stop valve;By opening and closing stop valve changes lower chamber pressure, so that upper and lower chambers form pressure difference, drive valve stem movement, to control lower chamber and liquid outlet passage break and make.Between the utility model is driven by controlling the pressure inside valve body to lift valve stem, complete dosing fluid injection mixing, and dosing fluid is with high pressure mode into raw material fluid passage, the impact force caused by turbulence, promote dosing and raw material mixing, improve mixing quality and efficiency.

Description

Technical Field

[0001] This utility model relates to the field of injection valve technology, specifically a fluid injection valve. Background Technology

[0002] Valves are widely used for flow regulation, on / off control, pressure control, backflow prevention, and safety protection. They can be classified into regulating valves, gate valves, back pressure valves, check valves, and safety valves according to their different functions. Valves are important control components for the transportation of fluid media.

[0003] In food, beverage, and pharmaceutical production, ingredients and additives are often mixed into the product materials. However, due to differences in density, viscosity, and molecular particle size between the ingredients / additives and the product materials, uneven mixing can occur, resulting in some product materials having insufficient levels of certain ingredients. This leads to waste of that portion of the product material, even though it is not contaminated and can be reused by adding the missing ingredients. The current conventional method is to collect this material in a container, add the missing ingredients, and mix it again. However, this method is time-consuming, reducing production efficiency, and the material may also affect its taste and quality if left for an extended period. Utility Model Content

[0004] To address the aforementioned technical problems, this utility model provides a fluid injection valve that controls the pressure inside the pipeline and valve body to drive the valve stem to rise and fall, thereby completing the online injection and mixing of the batching fluid. Furthermore, the batching fluid enters the raw material fluid channel under high pressure, and the resulting impact force creates turbulence, promoting the mixing of the batching and raw materials, improving the mixing quality and efficiency, as well as the utilization rate of unqualified materials.

[0005] To achieve its technical objectives, this utility model adopts the following technical solution:

[0006] A fluid injection valve includes a valve body, a valve stem, a pressure regulating component, and an injection head. The pressure regulating component is located at the upper end of the valve body, and the injection head is fixedly installed at the lower end. The bottom of the injection head has an outlet channel for connecting an external raw material fluid pipe. An inner cavity is formed between the pressure regulating component, the valve body, and the injection head. The valve stem passes through the valve body, and its lower end abuts against the bottom of the injection head. An isolation boss is provided on the outer periphery of the valve stem, abutting against the inner wall of the valve body. The isolation boss and the outer wall of the valve stem divide the inner cavity into an upper cavity and a lower cavity. The pressure regulating component is used to maintain a preset pressure in the upper cavity. A feed inlet pipe communicating with the lower cavity is provided on the side wall of the valve body. The feed inlet pipe is connected to a bypass return pipe with a shut-off valve. The pressure change of the feed fluid in the lower cavity is controlled by opening and closing the shut-off valve, so that a pressure difference is formed between the upper and lower cavities, driving the valve stem to move axially, thereby controlling the opening and closing of the lower cavity and the outlet channel.

[0007] Preferably, the pressure regulating assembly includes a spring and a pressure regulating nut. The outer wall of the pressure regulating nut and the inner wall of the upper end of the valve body are provided with mutually compatible threads. The pressure regulating nut is threadedly connected to the upper end of the valve body. The spring is sleeved on the upper section of the valve stem, and the lower end of the spring abuts against the isolation boss, and the upper end of the spring abuts against the pressure regulating nut.

[0008] More preferably, the pressure regulating assembly further includes a locking nut, the locking nut being annular and having threads on its inner wall, the locking nut being threaded onto the outer periphery of the pressure regulating nut and abutting against the upper end of the valve body.

[0009] Preferably, it further includes a welding seat, the valve body and the welding seat are fixedly connected by an annular round nut; the inner wall of the round nut is threadedly connected to the outer wall of the lower end of the valve body; a second protrusion extends outward from the upper edge of the welding seat, and a first protrusion is formed inward from the bottom of the round nut, the first protrusion abuts against the lower part of the second protrusion, and the round nut abuts against the welding seat through the first protrusion and the second protrusion.

[0010] More preferably, the injection head is fixedly mounted on the lower end of the valve body via the welding seat, the lower end of the injection head penetrates the bottom of the welding seat and the two are coaxially arranged, the side wall of the injection head is formed with a stepped block, the bottom of the welding seat is provided with an annular gasket for ensuring a seal between the welding seat and the injection head, the upper edge of the injection head is sandwiched between the second boss and the valve body, and the stepped block is pressed on top of the annular gasket.

[0011] Preferably, the side wall of the isolation boss is provided with two grooves at intervals, and a first O-ring is provided in each of the two grooves. The first O-ring abuts against the inner wall of the valve body and is used to achieve sealing and isolation between the upper cavity and the lower cavity.

[0012] Preferably, the lower end of the valve stem is a truncated cone, the injection head has an injection cavity with an upper opening, the bottom of the injection cavity is a mating surface adapted to the truncated cone, and the side wall of the lower end of the valve stem is fitted with a second O-ring through a groove, the second O-ring abutting against the mating surface.

[0013] More preferably, a third O-ring is provided on the upper end face of the injection head through a groove around the edge of the injection cavity, and the third O-ring abuts against the lower end of the valve body.

[0014] Preferably, when the shut-off valve is open, the feed fluid input into the feed inlet pipe and the lower chamber of the valve body circulates through the bypass return pipe, the lower chamber maintains a low pressure state, the pressure difference between the upper and lower chambers is small, and the outlet channel remains closed; when the shut-off valve is closed, the pressure in the lower chamber increases as the feed fluid continues to be input, and a sufficient pressure difference is formed between the upper and lower chambers to push the valve stem up, and the outlet channel opens.

[0015] More preferably, when the shut-off valve is open, the pressure in the lower chamber, the feed fluid pipeline, and the bypass return pipeline is between 0 and 1 bar, and the pressure in the raw material fluid pipeline is between 3 and 7 bar.

[0016] The beneficial effects of this utility model are as follows:

[0017] This utility model provides a fluid injection valve. Within a sealed cavity formed by the valve body, injection head, and valve stem, the valve stem is raised and lowered by controlling the pressure inside the pipeline and valve body. This controls the online injection and mixing of the feed fluid in the pipeline. During injection, the feed fluid enters the raw material fluid channel at high pressure, generating a certain impact force and creating turbulence, which promotes mixing with the raw material fluid. This reduces the time wasted in conventional mixing in containers and makes better use of substandard materials lacking feed ingredients. Attached Figure Description

[0018] Figure 1 This is an exploded view of the structure of this utility model;

[0019] Figure 2 yes Figure 1 Enlarged view of section A;

[0020] Figure 3 yes Figure 1 Enlarged view of section B;

[0021] Figure 4 This is a cross-sectional structural diagram of the present invention;

[0022] Figure 5 yes Figure 4 Enlarged view of section C;

[0023] Figure 6 This is a flow diagram of the raw materials in this utility model.

[0024] Figure label:

[0025] 1. Valve body; 2. Welding seat; 3. Round nut; 4. Annular gasket; 5. Injection head; 6. Valve stem; 7. Spring; 8. Pressure adjusting nut; 9. Scale bar; 10. Locking nut; 11. Isolation boss; 12. First O-ring seal; 13. Second O-ring seal; 14. Third O-ring seal; 15. Feeding inlet pipe; 16. Raw material fluid pipe; 17. First boss; 18. Second boss; 19. Step block; 20. Liquid outlet channel; 21. Vent. Detailed Implementation

[0026] In the description of this utility model, it should be noted that the terms "upper / lower," "front / rear," "inner / outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this utility model and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are only used to more clearly correspond to different connection positions in the description, and should not be construed as indicating or implying relative importance.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," and "connected," etc., should be interpreted broadly. For example, "connected" 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 a connection within the components of a compatible model. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances. Furthermore, unless otherwise specified, all components used in this application are commercially available components, and the connection between different components can be achieved through conventional technical means.

[0028] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0029] A fluid injection valve, such as Figures 1-6As shown, the device includes a valve body 1, a valve stem 6, a pressure regulating component, and an injection head 5. The upper end of the valve body 1 is equipped with a pressure regulating component, and the lower end is fixedly installed with an injection head 5. The bottom of the injection head 5 has an outlet channel 20 for connecting an external raw material fluid pipe 16. An inner cavity is formed between the pressure regulating component, the valve body 1, and the injection head 5. The valve stem 6 penetrates the valve body 1, and its lower end abuts against the bottom of the injection head 5, thereby closing the outlet channel 20. An isolation boss 11 is provided on the outer periphery of the valve stem 6, which abuts against the inner wall of the valve body 1. The isolation boss 11 divides the inner cavity into an upper cavity and a lower cavity. The pressure regulating component is used to maintain a preset pressure in the upper cavity. The side wall of the valve body 1 is provided with a feed inlet pipe 15 that communicates with the lower cavity. The feed inlet pipe 15 is connected to a bypass return pipe with a shut-off valve. The pressure change of the feed fluid in the lower cavity is controlled by opening and closing the shut-off valve, so that a pressure difference is formed between the upper and lower cavities, driving the valve stem 6 to move axially, thereby controlling the opening and closing of the lower cavity and the outlet channel 20.

[0030] Preferably, the pressure regulating assembly includes a spring 7 and a pressure regulating nut 8. The outer wall of the pressure regulating nut 8 and the inner wall of the upper end of the valve body 1 are provided with mutually compatible threads. The pressure regulating nut 8 is threadedly connected to the upper end of the valve body 1. The spring 7 is sleeved on the upper section of the valve stem 6, and the lower end of the spring 7 abuts against the isolation boss 11 and the upper end abuts against the pressure regulating nut 8.

[0031] As a preferred embodiment, the pressure regulating assembly further includes a locking nut 10, which is annular and has threads on its inner wall. The locking nut 10 is threaded onto the outer periphery of the pressure regulating nut 8 and abuts against the upper end of the valve body 1.

[0032] It is understandable that rotating the pressure adjusting nut 8 can change the compression of the spring 7, thereby setting the preset pressure of the upper chamber to meet the pressure requirements of different injection scenarios. After the pressure adjusting nut 8 is adjusted to the target position, tightening the locking nut 10 can fix the position of the pressure adjusting nut 8, prevent the pressure adjusting nut 8 from loosening due to vibration and other factors during the operation of the injection valve, and ensure the stability of the preset pressure of the upper chamber.

[0033] The upper part of the valve body 1 is provided with an annular groove, and one of the annular grooves is provided with an air hole 21. The air hole 21 is adapted to an external air pressure regulating device. When it is necessary to further optimize the stability of the upper chamber pressure, gas can be input or discharged into the air hole 21 through the external air pressure regulating device to assist in regulating the pressure of the upper chamber and avoid the pressure difference between the upper and lower chambers due to the pressure fluctuation of the upper chamber, thereby ensuring the stability of the movement of the valve stem 6. At the same time, the air hole 21 can monitor whether the seal in the middle of the valve stem 6 is damaged. If the seal is damaged, the liquid inside the valve body 1 will overflow through the air hole 21, which is convenient for the staff to repair and deal with it in time.

[0034] Preferably, the valve body 1 and the welding seat 2 are also included. The valve body 1 and the welding seat 2 are fixedly connected by an annular round nut 3. The inner wall of the round nut 3 is threadedly connected to the outer wall of the lower end of the valve body 1. The upper end of the welding seat 2 extends outward to the periphery with a second boss 18. The bottom of the round nut 3 forms a first boss 17 inward. The first boss 17 abuts against the lower part of the second boss 18. The round nut 3 abuts against the welding seat 2 through the first boss 17 and the second boss 18.

[0035] More preferably, the injection head 5 is fixedly installed at the lower end of the valve body 1 via the welding seat 2. The lower end of the injection head 5 penetrates the bottom of the welding seat 2 and the two are coaxially arranged. A stepped block 19 is formed on the side wall of the injection head 5. Specifically, the outer diameter of the upper section of the injection head 5 is larger than the outer diameter of the lower section. The upper edge of the injection head 5 is sandwiched between the second boss 18 and the valve body 1. An annular gasket 4 is provided around the bottom of the welding seat 2 around the injection head 5. The stepped block 19 is pressed on the top of the annular gasket 4. The annular gasket 4 is used to ensure the seal between the welding seat 2 and the injection head 5. By rotating the round nut 3, the first boss 17 drives the second boss 18 and the welding seat 2 to move upward and close to the side wall of the valve body 1. The edge of the injection head 5 is clamped between the valve body 1 and the second boss 18 of the welding seat 2. The stepped block 19 presses the annular gasket 4.

[0036] As a preferred option, such as Figure 2 As shown, the side wall of the isolation boss 11 is provided with two grooves at intervals, and a first O-ring 12 is provided in each of the two grooves. The first O-ring 12 abuts against the inner wall of the valve body 1. The first O-ring 12 is used to achieve sealing and isolation between the upper cavity and the lower cavity.

[0037] As a preferred option, such as Figures 3-5 As shown, the lower end of the valve stem 6 is a truncated cone (the remaining part after the cone horizontally cuts the tip). The injection head 5 has an injection chamber with an upper opening. The bottom of the injection chamber is a mating surface adapted to the truncated cone. The side wall of the lower end of the valve stem 6 is fitted with a second O-ring 13 through a groove. The second O-ring 13 abuts against the mating surface. The side wall of the upper end of the valve stem 6 is provided with a scale bar 9. The scale bar 9 is evenly distributed along the axial direction of the valve stem 6. The pressure adjustment component can be adjusted with the help of the scale bar 9 to accurately set the preset pressure of the upper chamber.

[0038] As a better option, such as Figure 5 As shown, a third O-ring 14 is provided on the upper end face of the injection head 5 through a groove around the edge of the injection cavity. The third O-ring 14 abuts against the lower end of the valve body 1.

[0039] To better control the injection timing, a liquid level sensor is installed on the inner wall of the raw material fluid channel 16 near the injection head 5. Other electronic components (control board, circuit, etc.) used in conjunction with the liquid level sensor are existing technologies, and those skilled in the art can purchase and install them according to actual needs, which will not be described in detail here.

[0040] When the shut-off valve is open, the feed fluid input into the feed inlet pipe 15 and the lower chamber of the valve body 1 circulates through the bypass return pipe, the lower chamber maintains a low pressure state, the pressure difference between the upper and lower chambers is small, and the outlet channel 20 remains closed; when the shut-off valve is closed, the pressure in the lower chamber increases as the feed fluid continues to be input, and a sufficient pressure difference is formed between the upper and lower chambers, which in turn pushes the valve stem 6 to rise, the lower end of the valve stem 6 and the contact surface of the injection head 5 are no longer in contact, and the outlet channel 20 opens.

[0041] More preferably, when the shut-off valve is open, the pressure in the lower chamber, the feed fluid pipeline 15, and the bypass return pipeline is between 0 and 1 bar, and the pressure in the raw material fluid pipeline 16 is between 3 and 7 bar.

[0042] The operation method of this utility model is as follows:

[0043] (a) Installation phase (preparation before use)

[0044] Before using this fluid injection valve, the following steps must be followed to complete the correct installation:

[0045] First, weld the welding seat 2 onto the raw material fluid pipeline 16. Before welding, the welding seat 2 should be placed in the center of the round nut 3, and the first boss 17 of the round nut 3 should be overlapped below the second boss 18 of the welding seat 2, in preparation for the subsequent assembly of the valve body 1.

[0046] Assemble the following sequence: annular gasket 4 - injection head 5 - third O-ring seal 14 - valve body 1. Place the annular gasket 4 at the bottom of the welding seat 2, insert the lower end of the injection head 5 through the lower end of the welding seat 2, install the third O-ring seal 14 in the groove above the injection head 5, press the lower end of the valve body 1 onto the injection head 5 and the welding seat 2, rotate the round nut 3 so that the first boss 17 abuts against the lower part of the second boss 18 to fix the welding seat 2 and the valve body 1, so that the edge of the injection head 5 is clamped between the valve body 1 and the second boss 18 of the welding seat 2, so that the third O-ring seal 14 is clamped between the valve body 1 and the injection head 5, and the step block 19 presses the annular gasket 4.

[0047] Assemble the valve stem 6: First, install the first O-ring 12 in the two annular grooves spaced apart on the side of the isolation boss 11 of the valve stem 6, and install the second O-ring 13 in the annular groove at the lower end of the valve stem 6. Then, insert the valve stem 6 from the top of the valve body 1 and pass through the center of the valve body 1 and the injection head 5 in sequence, ensuring that the first O-ring 12 fits against the inner wall of the valve body 1 and the second O-ring 13 fits against the contact surface of the injection head 5.

[0048] Assemble the pressure regulating assembly: Sleeve a spring 7 on the upper section of the valve stem 6, then thread the pressure regulating nut 8 to the upper end of the valve body 1 so that the bottom of the pressure regulating nut 8 fits against the upper end of the spring 7. Finally, thread a locking nut 10 onto the pressure regulating nut 8 so that the locking nut 10 and the upper end face of the valve body 1 fit and abut against each other.

[0049] Complete the installation of auxiliary components: Install a bypass return pipe on the feed inlet pipe 15 on the side of the valve body 1, and install a shut-off valve on the bypass return pipe; install a liquid level sensor on the raw material fluid pipe 16 (ensure that the liquid level sensor is close to the injection head 5).

[0050] Pressure preset: By rotating the pressure adjusting nut 8, and in conjunction with the scale bar 9 on the top of the valve stem 6, adjust the pressure to the required preset pressure value. After adjustment, tighten the locking nut 10 to fix the position of the pressure adjusting nut 8. The installation stage is now complete.

[0051] (ii) Standby mode

[0052] When the fluid injection valve is in the non-injection state, its working process is as follows:

[0053] Circulation of the mixing fluid: The mixing fluid is pumped from the container containing the mixing fluid to the mixing inlet pipe 15 on the side of the valve body 1. At this time, the shut-off valve on the bypass return pipe is open, and the mixing fluid entering the mixing inlet pipe 15 will flow back to the container containing the mixing fluid through the bypass return pipe, forming a circulation. At the same time, some of the mixing fluid will enter the lower cavity formed by the valve body 1, the valve stem 6, and the injection head 5, so that the lower cavity, the mixing inlet pipe 15, and the bypass return pipe maintain a certain pressure (the measured pressure is usually 0-1 bar).

[0054] The state of the raw material fluid: Raw material fluid continuously flows through the raw material fluid pipeline 16, and the pressure inside the raw material fluid pipeline 16 is 3-7 bar, which is higher than the pressure in the lower chamber;

[0055] Stability of valve stem 6: The spring 7 in the pressure regulating assembly provides downward pressure to valve stem 6. This downward pressure is balanced with the pressure in the lower chamber and the pressure in the raw material fluid pipeline 16, preventing valve stem 6 from lifting upward. At the same time, all O-rings work together to maintain the seal at each joint, preventing the raw material fluid in the raw material fluid pipeline 16 from entering the valve body 1, and ensuring that the injection valve is in a standby sealed state.

[0056] (III) Injection Status (Injection of Feeding Fluid)

[0057] When the level sensor detects that the raw material fluid has passed through the raw material fluid pipeline 16 and the preset injection requirements have been met, the injection valve enters the injection state. The specific process is as follows:

[0058] Pressure preset confirmation: If the injection pressure needs to be adjusted, the specific pressure value can be reset by rotating the pressure adjusting nut 8 according to the scale bar 9 on the top of the valve stem 6 to ensure that the preset pressure of the upper chamber meets the injection requirements.

[0059] Ingredient fluid path switching: After starting the injection process, close the shut-off valve on the bypass return pipeline to block the return path of the ingredient fluid; at this time, the pump body continuously delivers the ingredient fluid to the ingredient inlet pipeline 15, and the pressure inside the ingredient inlet pipeline 15 and the lower chamber will rise instantly.

[0060] Valve stem 6 movement and fluid injection: When the pressure in the lower chamber is higher than the preset pressure in the upper chamber, it will push the valve stem 6 to move upward. During the upward movement of the valve stem 6, the spring 7 will be compressed. At the same time, the feed fluid in the lower chamber is injected into the raw material fluid pipeline 16 through the liquid outlet channel 20 of the injection head 5. The feed fluid is mixed online with the raw material fluid in the raw material fluid pipeline 16, eliminating the need for additional stirring in the container and reducing mixing time and raw material loss. During this process, all O-rings remain sealed to prevent fluid leakage.

[0061] (iv) Reset after injection (restore standby state)

[0062] After the injection valve completes the injection according to the preset injection requirements, it enters the reset stage: at this time, the shut-off valve on the bypass return pipe reopens, the pressure inside the feed inlet pipe 15 and the lower chamber is instantly released, and the feed fluid flows back to the container containing the feed fluid through the bypass return pipe to form a new cycle; at the same time, the rebound force of the spring 7 pushes the valve stem 6 downward to reset, returning to the sealed position when not injecting, and all O-rings are tightly fitted again to maintain the sealing state. The entire injection process is now complete, and the injection valve waits for the next injection command.

[0063] Although the embodiments of this utility model have been described in the specification, these embodiments are merely illustrative and should not limit the scope of protection of this utility model. Various omissions, substitutions, and modifications made without departing from the spirit of this utility model should be included within the scope of protection of this utility model.

Claims

1. A fluid injection valve, characterized in that, The device includes a valve body, a valve stem, a pressure regulating component, and an injection head. The pressure regulating component is located at the upper end of the valve body, and the injection head is fixedly installed at the lower end. The bottom of the injection head has an outlet channel for connecting to an external raw material fluid pipe. An inner cavity is formed between the pressure regulating component, the valve body, and the injection head. The valve stem passes through the valve body, and its lower end abuts against the bottom of the injection head. An isolation boss is provided on the outer periphery of the valve stem, abutting against the inner wall of the valve body. The isolation boss and the outer wall of the valve stem divide the inner cavity into an upper cavity and a lower cavity. The pressure regulating component is used to maintain a preset pressure in the upper cavity. A dispensing inlet pipe communicating with the lower cavity is provided on the side wall of the valve body. The dispensing inlet pipe is connected to a bypass return pipe with a shut-off valve. The pressure change of the dispensing fluid in the lower cavity is controlled by opening and closing the shut-off valve, so that a pressure difference is formed between the upper and lower cavities, driving the valve stem to move axially, thereby controlling the opening and closing of the lower cavity and the outlet channel.

2. A fluid injection valve as described in claim 1, characterized in that, The pressure regulating assembly includes a spring and a pressure regulating nut. The outer wall of the pressure regulating nut and the inner wall of the upper end of the valve body are provided with mutually compatible threads. The pressure regulating nut is threadedly connected to the upper end of the valve body. The spring is sleeved on the upper section of the valve stem, and the lower end of the spring abuts against the isolation boss and the upper end abuts against the pressure regulating nut.

3. A fluid injection valve as described in claim 2, characterized in that, The pressure regulating assembly also includes a locking nut, which is annular and has threads on its inner wall. The locking nut is threaded onto the outer periphery of the pressure regulating nut and abuts against the upper end of the valve body.

4. A fluid injection valve as described in claim 1, characterized in that, It also includes a welding seat, the valve body and the welding seat are fixedly connected by an annular round nut; the inner wall of the round nut is threadedly connected to the outer wall of the lower end of the valve body; the upper edge of the welding seat has a second protrusion extending outward, the bottom of the round nut has a first protrusion forming inward, the first protrusion abuts against the lower part of the second protrusion, and the round nut abuts against the welding seat through the first protrusion and the second protrusion.

5. A fluid injection valve as described in claim 4, characterized in that, The injection head is fixedly mounted on the lower end of the valve body via the welding seat. The lower end of the injection head passes through the bottom of the welding seat and the two are coaxially arranged. A stepped block is formed on the side wall of the injection head. An annular gasket is provided around the bottom of the welding seat to ensure a seal between the welding seat and the injection head. The upper edge of the injection head is sandwiched between the second boss and the valve body. The stepped block is pressed on top of the annular gasket.

6. A fluid injection valve as described in claim 1, characterized in that, The isolation boss has two grooves spaced apart on its side wall. Each groove contains a first O-ring seal. The first O-ring seal abuts against the inner wall of the valve body and is used to achieve sealing and isolation between the upper and lower cavities.

7. A fluid injection valve as described in claim 1, characterized in that, The lower end of the valve stem is a truncated cone, and the injection head has an injection cavity with an upper opening. The bottom of the injection cavity is a mating surface adapted to the truncated cone. The side wall of the lower end of the valve stem is fitted with a second O-ring through a groove, and the second O-ring abuts against the mating surface.

8. A fluid injection valve as described in claim 7, characterized in that, The upper end face of the injection head is provided with a third O-ring through a groove around the edge of the injection cavity, and the third O-ring abuts against the lower end of the valve body.

9. A fluid injection valve as described in claim 1, characterized in that, When the shut-off valve is open, the feed fluid input into the feed inlet pipe and the lower chamber of the valve body circulates through the bypass return pipe, the lower chamber maintains a low pressure state, the pressure difference between the upper and lower chambers is small, and the outlet channel remains closed; when the shut-off valve is closed, the pressure in the lower chamber increases as the feed fluid continues to be input, and a sufficient pressure difference is formed between the upper and lower chambers to push the valve stem up, and the outlet channel opens.

10. A fluid injection valve as described in claim 9, characterized in that, When the shut-off valve is open, the pressure in the lower chamber, the feed fluid pipeline, and the bypass return pipeline is between 0 and 1 bar, and the pressure in the raw material fluid pipeline is between 3 and 7 bar.

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