Balancing valve for a tunnel foam system

Abstract

The application belongs to the technical field of valves, and particularly relates to a balance valve for a tunnel foam system, which comprises a valve body and a valve cover, the valve body and the valve cover are connected through bolts, a cavity is formed between the valve body and the valve cover, a valve plate is slidably connected in the cavity, the valve plate divides the cavity into a water cavity and a foam cavity, a communication port for accommodating a water source is arranged on the valve body and communicates with the water cavity, water flow is increased, water flows into the water cavity to increase water pressure in the water cavity, the valve plate is pushed to move towards the foam cavity, the space of the foam cavity is reduced, the foam cavity is compressed by the valve plate, the valve plate is close to the valve cover, the extension part of the valve plate also moves, the distance between the extension part and the closing block is increased, foam liquid circulation is facilitated, foam liquid flow is increased, water flow is increased, foam liquid flow is simultaneously controlled to be increased, and water flow and foam liquid are uniformly ensured.

Description

Technical Field

[0001] This invention discloses a balancing valve, and more particularly relates to a balancing valve for use in a tunnel foam system. Background Technology

[0002] In foam fire extinguishing systems, fire water and foam concentrate need to be mixed in a specific ratio during firefighting. The pressure of the fire water varies within a certain range, and the pressure of the foam concentrate must also change synchronously with the pressure of the fire water. Currently, balancing valves are generally used to control the mixing of fire water and foam concentrate. Traditional balancing valves use diaphragm seals, which have poor reliability. Balancing valves that control the flow rate of foam concentrate via pistons have been developed on the market. This type of control method is relatively stable and accurate once the flow rate is adjusted when needed. However, adjustments are required when balance is needed or when different states are required, which is inconvenient. Therefore, a new solution is proposed that ensures stable control while also achieving automatic control. Summary of the Invention

[0003] The purpose of this invention is to provide a balancing valve for a tunnel foam system in order to solve the above-mentioned problems.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a balancing valve for a tunnel foam system, comprising a valve body and a valve cover, wherein the valve body and the valve cover are connected by bolts, forming a cavity between the valve body and the valve cover, and a valve plate is slidably connected within the cavity, the valve plate dividing the cavity into a water cavity and a foam cavity, the valve body having a connecting port communicating with the water cavity and accommodating the entry of water, the valve cover having an inlet accommodating the entry of foam liquid, the valve body having an outlet accommodating the outflow of foam liquid, the valve plate having a through hole communicating with the outlet and the inlet, the valve plate having an extension portion facing the outlet, the valve body having a sealing block at the outlet abutting against the extension portion of the valve plate, the through hole of the valve plate being located at the extension portion, and the through hole being sealed by abutting against the sealing block through the extension portion, a spring being provided between the valve plate and the valve cover, the edge of the valve plate having a protrusion abutting against and sliding against the valve body and the valve cover, and the protrusion having a semi-I-shaped cross-section, and the valve cover having a pressure-reducing component for reducing the pressure of the foam liquid.

[0005] Preferably, the pressure-reducing assembly includes an insert disposed at the bottom of the protrusion, the valve cover is provided with a groove communicating with the foam cavity and used to reduce the pressure of the foam cavity, a blocking block for closing the groove is slidably connected to the valve cover, the valve cover is provided with a slot for receiving the insert embedded in the slot at one end of the blocking block, and the blocking block is pushed and moved by the insert, and the blocking block is provided with an opening that is misaligned with the groove.

[0006] Preferably, the blocking block is provided with a one-way drain outlet 1 that communicates with the groove and the foam cavity. The drain outlet 1 is frustum-shaped and contains a rubber ball. The diameter of the two ends of the drain outlet 1 is smaller than that of the rubber ball at one end and larger than that of the rubber ball at the other end. A spring 2 is provided between the blocking block and the valve cover. The contact surface between the blocking block and the plug is an arc surface.

[0007] Preferably, the insert is provided with an abutment block that fits against the blocking block, and a movable part is slidably connected to the valve cover at the position where the insert is embedded. The movable part is provided with a limiting block that abuts against the abutment block and is used to limit the abutment block. A spring is provided between the limiting block and the movable part, and a cylinder is provided outside the valve cover to drive the movable part to move.

[0008] Preferably, the plug-in has a connecting block at the lower end of the abutment block, the connecting block is slidably connected to the plug-in, the abutment surface of the abutment block and the limiting block is an arc surface, and after the limiting block moves to the bottom of the abutment block, the abutment surface of the limiting block is perpendicular to the abutment block, the upper and lower surfaces of the connecting block are both arc surfaces, the abutment block is provided with a limiting groove for accommodating the insertion of the connecting block, the connecting block pushes the connecting block upward and inserts it into the limiting groove through the limiting block, and the elastic force of the spring three is greater than the weight of the connecting block.

[0009] Preferably, the valve cover is provided with a support block that is offset from the moving part, the support block is slidably connected to the valve cover, and a cylinder is provided outside the valve cover to push the support block into the foam cavity and abut against the protrusion and support the protrusion.

[0010] Preferably, the valve body has a drainage channel on the inner wall of the water cavity, and the drainage channel is located in the water cavity as a water inlet. The drainage channel is arc-shaped, and the end of the drainage channel away from the water inlet is a second drain outlet, which is located in the recessed part of the protrusion.

[0011] Preferably, the valve body is equipped with a switch 1 and a switch 2 at the front end of the communication port to control the opening of cylinder 1 and cylinder 2.

[0012] Compared with the prior art, the beneficial effects of the present invention are: Firstly, in a foam fire extinguishing system, it is necessary to ensure that the foam water discharged from the outlet reaches the required uniform state. This requires mixing the foam liquid and water at a uniform flow rate. When the water flow rate is changed, the foam liquid needs to be automatically adjusted. By using this device, the water flow rate is controlled by the connecting port at the front end of the valve body. As the water flow rate increases, the water pressure in the water chamber increases, pushing the valve plate towards the foam chamber. This reduces the space of the foam chamber, and the valve plate compresses the foam chamber, bringing the valve plate closer to the valve cover. At the same time, the extension of the valve plate also moves away from the sealing block, increasing the distance between the extension and the sealing block, facilitating the flow of foam liquid, and increasing the flow rate of foam liquid. Thus, the increased water flow rate can be synchronously controlled to increase the foam liquid flow rate, thereby ensuring the uniformity of the water flow rate and the foam liquid flow rate and achieving a balance between them. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of a balancing valve used in a tunnel foam system. Figure 2 A schematic diagram of the internal structure of a balancing valve used in a tunnel foam system. Figure 1 ; Figure 3 A schematic diagram of the internal structure of a balancing valve used in a tunnel foam system. Figure 2 ; Figure 4 for Figure 2 A magnified view of a portion at point A; Figure 5 This is a schematic diagram of the internal structure of the valve cover and valve plate. Figure 6 for Figure 5 A magnified view of the area at point C; Figure 7 for Figure 2 A magnified view of the area at point B; Figure 8 This is a schematic diagram of the structure where the plug-in and the moving part mate. Figure 9 This is a schematic diagram of the internal structure of the valve cover.

[0014] Reference numerals: 1. Valve body; 2. Valve cover; 3. Valve plate; 4. Water chamber; 5. Foam chamber; 6. Connecting port; 7. Inlet; 8. Outlet; 9. Perforation; 10. Extension; 11. Sealing block; 12. Spring 1; 13. Protrusion; 14. Insert; 15. Groove; 16. Blocking block; 17. Slot; 18. Opening; 19. Drain outlet 1; 20. Rubber ball; 21. Spring 2; 22. Abutment block; 23. Moving part; 24. Limiting block; 25. Spring 3; 26. Cylinder 1; 27. Connecting block; 28. Limiting groove; 29. ​​Support block; 30. Cylinder 2; 31. Drainage channel; 32. Water inlet; 33. Drain outlet 2. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. In this description, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the present invention and 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 the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. 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.

[0016] A balancing valve for a tunnel foam system, such as Figures 1-9As shown, the device includes a valve body 1 and a valve cover 2. The valve body 1 and the valve cover 2 are connected by bolts, forming a cavity between them. A valve plate 3 is slidably connected within the cavity, dividing the cavity into a water cavity 4 and a foam cavity 5. The valve body 1 has a connecting port 6 that communicates with the water cavity 4 and allows water to enter. The valve cover 2 has an inlet 7 that allows foam liquid to enter. The valve body 1 has an outlet 8 that allows foam liquid to flow out. The valve plate 3 has a through hole 9 that communicates with the outlet 8 and the inlet 7. The valve plate 3 has an extension 10 facing the outlet 8. The valve body 1 has a sealing block 11 at the outlet 8 that abuts against the extension 10 of the valve plate 3. The through hole 9 of the valve plate 3 is located at the extension 10, and the through hole 9 is sealed by abutting against the sealing block 11 through the extension 10. A spring 12 is provided between valve plate 3 and valve cover 2. A protrusion 13 is provided on the edge of valve plate 3, which abuts against and slides against valve body 1 and valve cover 2. The protrusion 13 has a semi-I-shaped cross-section. A pressure-reducing component is provided on valve cover 2 to reduce the pressure of the foam liquid. Normally, when using the balance valve, the fire-fighting foam extinguishing system needs to mix foam liquid with water before outputting it. The foam valve and water valve should be pre-adjusted according to the required flow rate to ensure that the water and foam liquid flow rates are appropriate and automatically mixed before spraying for fire extinguishing. However, existing methods can only guarantee a fixed flow rate through pre-adjustment. If the water flow increases, the mixing ratio will become uneven. Therefore, current methods can only use electronic control to connect two valves in series to ensure that one end controls the other, which automatically opens and adjusts to maintain the flow ratio. Stable and accurate, this device is used to control the flow of fire-fighting water by installing a valve at the front end of the connecting port 6 of the valve body 1. When more water is needed, the valve at the front end of the connecting port 6 is opened, allowing water to enter the valve body 1 through the connecting port 6. Because the valve plate 3 divides the cavity formed in the valve body 1 and the valve cover 2 into a water cavity 4 that communicates with the connecting port 6 and a foam cavity 5 located opposite the water cavity 4 of the valve plate 3, the water flows into the water cavity 4 but does not fill it completely, causing the pressure in the water cavity 4 to increase. At the same time, the water flow in the external water pipe increases, and the increased water pressure in the water cavity 4 pushes the valve plate 3 towards the foam cavity 5, compressing the foam cavity 5. This causes the valve plate 3 to move the extension 10 closer to the valve cover 2, making the extension 10 closer to the sealing block 11. The increased distance between the extension 10 and the sealing block 11 creates a gap between the sealing block 11 and the valve body 1 to allow the foam liquid to flow through. This increases the distance between the extension 10 and the sealing block 11, allowing the outflowing foam liquid to flow into the outlet 8 more quickly and easily. Simultaneously, the extension 10 removes the obstruction to the sealing block 11 and the gap, increasing the water flow rate as it is discharged from the outlet 8 and mixes with the fire-fighting water flow. Conversely, when the water flow at the connecting port 6 decreases and the internal water pressure decreases, the foam liquid flows normally and fills the foam chamber 5 normally. This reduces the pressure in the water chamber 4, causing the foam chamber 5 to push the valve plate 3 to reset or reduce the size of the water chamber 4, thus moving the valve plate 3 and bringing the extension 10 closer to the sealing block 11. This reduces the outflow of foam liquid. Through the above configuration, it is ensured that as long as the valve controlling the water flow in the pipeline adjusts and changes the water flow...The foam liquid flow rate is automatically adjusted to ensure that the fire-fighting water flow and foam liquid flow are regulated simultaneously, avoiding large differences in the ratio. This ensures a more uniform mixing ratio, making it convenient for fire extinguishing. Furthermore, the above-mentioned settings facilitate faster and more convenient adjustment compared to manual adjustment, and are more cost-effective and simpler than electronic control adjustment.

[0017] The pressure-reducing assembly includes an insert 14 located at the bottom of the protrusion 13. The valve cover 2 has a groove 15 that communicates with the foam chamber 5 and reduces the pressure in the foam chamber 5. A blocking block 16 is slidably connected to the valve cover 2 to close the groove 15. One end of the valve cover 2 located at the blocking block 16 has a slot 17 for receiving the insert 14, and the blocking block 16 is pushed and moved by the insert 14. The blocking block 16 has an opening 18 that is misaligned with the groove 15. Increased water flow through the pipe and into the connecting port 6 leads to increased water flow into the water chamber 4, increasing the pressure within the water chamber 4. This pressure is pushed and moved by the valve plate 3, compressing the spring 12 and causing the protrusion 13 and insert 14 to move synchronously. The movement is stable due to the action of the protrusion 13 and spring 12, preventing any... In the case of tilting and offset, when the plug-in 14 moves down, it first abuts against the blocking block 16 on the slot 17. Through the abutment of the arc surface, the continuous downward movement will push the blocking block 16 to move backward and drive the opening 18, which is misaligned with the groove 15, to move from the misaligned state to the connected state. At this time, the groove 15 is opened, allowing the foam liquid to enter the groove 15. When squeezed, the foam liquid in the foam cavity 5 moves backward and flows back to reduce the blocking pressure, thereby reducing the pressure and ensuring that the water flow changes more easily to push the valve plate 3 to move, so that the foam liquid can change the flow rate synchronously. Conversely, when the water flow rate decreases and the water pressure decreases, the spring 12 can quickly push the valve plate 3 to reset, avoiding the situation where the valve plate 3 is not pushed due to insufficient foam liquid pressure. The function of the spring 12 is to ensure accurate reset.

[0018] The blocking block 16 is provided with a one-way drain outlet 19 communicating with the groove 15 and the foam cavity 5. The drain outlet 19 is frustoconical, and a rubber ball 20 is provided inside the drain outlet 19. The diameter of the drain outlet 19 at one end is smaller than that of the rubber ball 20, and the diameter at the other end is larger than that of the rubber ball 20. A spring 21 is provided between the blocking block 16 and the valve cover 2. The contact surface between the blocking block 16 and the insert 14 is an arc surface. When the water pressure in the water cavity 4 decreases, the spring 12 pushes the valve plate 3 to reset, which in turn drives the insert 14 and the protrusion 13 to reset. At this time, the obstruction of the blocking block 16 is released, and the spring 21 will push the blocking block 16 to reset, thus opening the valve. When the opening 18 is repositioned to the groove 15, there is a possibility that the foam liquid inside may not be able to drain and may accumulate excessively. Therefore, after sealing, the foam liquid is drained through the one-way drain outlet 19. The foam liquid pushes the internal rubber ball 20 towards the larger diameter end of the drain outlet 19, thus allowing the internal foam liquid to drain out. However, if the foam cavity 5 is full of foam liquid, it will rush into the drain outlet 19 and push the rubber ball 20 upward. At the same time, it will move the rubber ball 20 along the larger diameter end of the drain outlet 19 to the smaller diameter end, thus sealing the drain outlet 19 and ensuring that the foam liquid does not rush into the groove 15.

[0019] The plug-in 14 is provided with an abutment block 22 that fits against the blocking block 16. A movable component 23 is slidably connected to the valve cover 2 at the position where the plug-in 14 is embedded. The movable component 23 is provided with a limiting block 24 that abuts against the abutment block 22 and restricts the abutment block 22. A spring 25 is provided between the limiting block 24 and the movable component 23. A cylinder 26 is provided outside the valve cover 2 to drive the movable component 23. A switch 1 and a switch 2 are provided at the front end of the valve body 1 near the connecting port 6 to control the opening of the cylinder 26 and the cylinder 30. Under normal use, the valve at the front end of the connecting port 6 controls the flow of fire-fighting water. Increasing the fire-fighting water flow increases the foam liquid flow, while decreasing the water flow decreases the foam liquid flow. However, in special cases where a thicker foam liquid is required, the valve at the front end of the connecting port 6 needs to be closed. When the valve's water flow adjustment is closed, the pressure disappears, and the valve plate 3 resets, reducing the foam liquid flow. Therefore, when a large amount of foam liquid is needed, the valve switch is opened first, and then the switch is controlled to open the controller cylinder 26, which moves the moving part 23. The moving part 23 moves the limit block 24 towards the plug-in 14. The limit block 24 and the plug-in 14 abut against the abutment block 22. The limit block 24 is pushed backward along the arc surface to compress the spring 3 25, and then moves to the vertical surface at the bottom of the abutment block 22. The vertical surfaces fit together to restrict the abutment block 22 and the plug-in 14 from moving downward, thereby restricting the protrusion 13 and the valve plate 3 from resetting. After this state, the valve is closed to reduce the water pressure. The valve plate 3 will not be pushed back to its original position. The foam liquid output can maintain the flow rate, while the fire water flow rate decreases. The foam liquid continues to increase. Thus, the mixed output can make the discharged foam more and more concentrated. Therefore, when a concentrated foam is needed, more foam can be produced by the above settings.

[0020] The plug-in 14 is located at the lower end of the abutment block 22 and has a connecting block 27. The connecting block 27 is slidably connected to the plug-in 14. The abutment surfaces of the abutment block 22 and the limiting block 24 are arc surfaces, and after the limiting block 24 moves to the bottom of the abutment block 22, it is perpendicular to the abutment surface of the abutment block 22. The upper and lower surfaces of the connecting block 27 are arc surfaces. The abutment block 22 has a limiting groove 28 for accommodating the insertion of the connecting block 27. The connecting block 27 is pushed upward by the limiting block 24 and inserted into the limiting groove 28. The elastic force of the spring 3 25 is greater than the weight of the connecting block 27. After the above settings are configured, the restriction on the plug-in 14 needs to be released before the switch is turned on. The drive is repeated, and the control cylinder 26 pushes again, causing the moving part 23 to move down again. At the same time, it drives the limiting block 24 to continue to move down and away from the abutment block 22, and moves again to abut against the connecting block 27 on the plug-in 14. After moving down to the bottom of the connecting block 27, the cylinder 26 closes, and the cylinder 26 automatically resets, driving the moving part 23 to reset. At this time, the moving part 23 pulls the limiting block 24 up. The limiting block 24 cannot move down because the connecting block 27 cannot move down. Therefore, under the blocking force and the pushing force of the moving part 23, the limiting block 24 is pushed along the arc surface of the connecting block 27 towards the spring 25. When the cylinder moves and compresses the spring 25, and moves to the bottom of the connecting block 27, the spring's thrust clamps the connecting block 27, causing the cylinder 26 to reset. As the moving part 23 moves upward, it lifts the connecting block 27 upward via the limiting block 24. Because the connecting block 27 can move upward and its weight is less than the spring force, the spring 25 does not compress when the limiting block 24 moves upward; instead, it moves the connecting block 27 upward synchronously. When the upper arc surface of the connecting block 27 is embedded in the limiting groove 28 at the bottom of the abutment block 22, the connecting block 27 is blocked from moving upward, but the moving part 23 continues to move upward. At this point, the blocking force... With the push force, the limiting block 24 can be pushed inward and disengaged from the connecting block 27. Since the connecting block 27 and the abutment block 22 are the same size, the limiting block 24 can move along the connecting block 27 and disengage from the abutment block 22 after being attached, thus canceling the restriction and achieving release. The switch will not close the first time it is turned on, but will remain in the holding state. After the second start, it will automatically close. The degree of push for the two openings can also be set in advance, thereby achieving restriction and automatic release. The switch is located at the valve at the front end of the connecting port 6, which is convenient for operation and can also be operated in the control room. This is the existing electronic control technology and will not be discussed in detail here.

[0021] The valve cover 2 is provided with a support block 29 that is offset from the moving part 23. The support block 29 is slidably connected to the valve cover 2. The valve cover 2 is provided with a cylinder 30 that pushes the support block 29 into the foam cavity 5 and abuts against the protrusion 13 and supports the protrusion 13. The valve body 1 is provided with a drainage channel 31 on the inner wall of the water cavity 4. The drainage channel 31 is located in the water cavity 4 and is the water inlet 32. The drainage channel 31 is arc-shaped, and the end of the drainage channel 31 away from the water inlet 32 ​​is the drain outlet 33. The drain outlet is located in the middle of the recess of the protrusion 13. When foam liquid is not needed, by turning on the control switch 2 on the controller, or by manually turning on the switch 2, the cylinder 2 30 drives the support block 29 to embed into the foam cavity 5 and abut against the protrusion 13, supporting and restricting the protrusion 13. At the same time, the support block 29 and the plug 14 are misaligned to ensure that the use of the plug 14 is not affected. After being supported by the support block 29, the valve at the front end of the connecting port 6 opens to output water flow into the water cavity 4, but it cannot push the valve plate 3 towards the foam cavity 5. This ensures that the extension 10 and the sealing block 11 fit together, ensuring that the foam liquid does not flow out excessively. Secondly, when the water flows in, it will also enter the drain channel 31 through the inlet 32, and then be discharged from the drain port 2 33 into the concave position of the protrusion 13. This supports and pushes the valve plate 3, preventing the valve plate 3 from moving and ensuring the stability of the valve plate 3. This ensures that the water flow rate increases while the foam liquid discharges less or stops. Under normal use, this automatically controls and balances the flow rates of the two liquids. When changes are needed temporarily, it is also easy to adjust automatically. Compared with manual adjustment in existing technologies, this is more convenient. Compared with electronically controlled balancing, the above setting is more convenient to adjust and automatically and stably adjusts synchronously. It is simpler and can be externally controlled to change and adjust the flow in different states.

[0022] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0023] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A balancing valve for a tunnel foam system, comprising a valve body (1) and a valve cover (2), wherein the valve body (1) and the valve cover (2) are connected by bolts, characterized in that: A cavity is formed between the valve body (1) and the valve cover (2). A valve plate (3) is slidably connected inside the cavity. The valve plate (3) divides the cavity into a water cavity (4) and a foam cavity (5). The valve body (1) is provided with a connecting port (6) that communicates with the water cavity (4) and allows water to enter. The valve cover (2) is provided with an inlet (7) that allows foam liquid to enter. The valve body (1) is provided with an outlet (8) that allows foam liquid to flow out. The valve plate (3) is provided with a perforation (9) that communicates with the outlet (8) and the inlet (7). The valve plate (3) is provided with an extension (1) facing the outlet (8). 0), the valve body (1) is provided with a sealing block (11) at the outlet (8) that abuts against the extension (10) of the valve plate (3), the through hole (9) of the valve plate (3) is located at the extension (10), and the through hole (9) is sealed by abutting against the sealing block (11) through the extension (10), a spring (12) is provided between the valve plate (3) and the valve cover (2), the edge of the valve plate (3) is provided with a protrusion (13) that abuts against and slides against the valve body (1) and the valve cover (2), and the cross section of the protrusion (13) is half I-shaped, and a pressure reducing component for reducing the pressure of the foam hydraulic pressure is provided on the valve cover (2); The pressure-reducing assembly includes a plug (14) disposed at the bottom of the protrusion (13), a groove (15) on the valve cover (2) that is connected to the foam cavity (5) and is used to reduce the pressure of the foam cavity (5), a blocking block (16) for closing the groove (15) is slidably connected on the valve cover (2), a slot (17) for receiving the plug (14) is provided at one end of the valve cover (2) located on the blocking block (16), and the blocking block (16) is pushed and moved by the plug (14), and an opening (18) is provided on the blocking block (16) that is misaligned with the groove (15).

2. The balancing valve for a tunnel foam system according to claim 1, characterized in that: The blocking block (16) is provided with a one-way drain outlet (19) that communicates with the groove (15) and the foam cavity (5). The drain outlet (19) is frustum-shaped. A rubber ball (20) is provided inside the drain outlet (19). The diameter of the two ends of the drain outlet (19) is smaller than that of the rubber ball (20) at one end and larger than that of the rubber ball (20) at the other end. A spring (21) is provided between the blocking block (16) and the valve cover (2). The contact surface between the blocking block (16) and the plug (14) is an arc surface.

3. A balancing valve for a tunnel foam system according to claim 1, characterized in that: The plug (14) is provided with an abutment block (22) that fits against the blocking block (16). The valve cover (2) is slidably connected to a moving part (23) at the position where the plug (14) is embedded. The moving part (23) is provided with a limiting block (24) that abuts against the abutment block (22) and is used to limit the abutment block (22). A spring three (25) is provided between the limiting block (24) and the moving part (23). A cylinder one (26) is provided outside the valve cover (2) to drive the moving part (23) to move.

4. A balancing valve for a tunnel foam system according to claim 3, characterized in that: The plug (14) is provided with a connecting block (27) at the lower end of the abutment block (22). The connecting block (27) is slidably connected to the plug (14). The abutment surface of the abutment block (22) and the limiting block (24) is an arc surface. After the limiting block (24) moves to the bottom of the abutment block (22), the abutment surface of the limiting block (22) is perpendicular to the abutment block (22). The upper and lower surfaces of the connecting block (27) are arc surfaces. The abutment block (22) is provided with a limiting groove (28) for accommodating the embedded connecting block (27). The connecting block (27) is pushed upward and embedded into the limiting groove (28) by the limiting block (24). The elastic force of the spring three (25) is greater than the self-weight of the connecting block (27).

5. A balancing valve for a tunnel foam system according to claim 3, characterized in that: The valve cover (2) is provided with a support block (29) that is offset from the moving part (23). The support block (29) is slidably connected to the valve cover (2). The valve cover (2) is provided with a cylinder two (30) that pushes the support block (29) into the foam cavity (5) and abuts against the protrusion (13) and supports the protrusion (13).

6. A balancing valve for a tunnel foam system according to claim 1, characterized in that: The valve body (1) has a drainage channel (31) on the inner wall of the water cavity (4), and the drainage channel (31) is located in the water cavity (4) as the inlet (32). The drainage channel (31) is arc-shaped, and the end of the drainage channel (31) away from the inlet (32) is the second drain outlet (33). The drain outlet is located in the middle recess of the protrusion (13).

7. A balancing valve for a tunnel foam system according to claim 5, characterized in that: The valve body (1) is equipped with a switch one and a switch two at the front end of the connecting port (6) to control the opening of cylinder one (26) and cylinder two (30).

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