A negative pressure well based on pneumatic control
By using a pneumatic control system that links the float to the gas path, the problem of not being able to track liquid level changes in traditional negative pressure wells in real time has been solved, thus achieving stable operation of negative pressure wells and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANDONG WENYUAN BUILDING MATERIALS TECH
- Filing Date
- 2025-06-20
- Publication Date
- 2026-06-26
Smart Images
Figure CN224412749U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of well technology, and in particular to a negative pressure well based on pneumatic control. Background Technology
[0002] Negative pressure wells are used in rural domestic sewage collection projects, primarily to collect sewage discharged from residents' courtyards. The sewage discharged from these courtyards does not flow directly through pipes but is temporarily stored in the collection well. The purpose of this storage is to facilitate more efficient discharge.
[0003] Traditional negative pressure wells may rely on fixed liquid level thresholds (such as high and low liquid level switches), making it impossible to track continuous changes in liquid level in real time, leading to delayed drainage or frequent start-stop cycles. Since sewage in negative pressure wells is pumped away by negative pressure, if pumping is initiated as soon as sewage enters, frequent starts will occur, increasing not only the wear and tear on mechanical equipment but also energy consumption. Utility Model Content
[0004] To reduce the likelihood of frequent start-ups and shutdowns of negative pressure wells, this application provides a negative pressure well based on pneumatic control.
[0005] The negative pressure well based on pneumatic control provided in this application adopts the following technical solution:
[0006] A pneumatically controlled negative pressure well includes a collection well with an inlet and outlet pipe connected to the outside. It also includes a float, a pneumatic switching device, and a pneumatic opening and closing device. The pneumatic opening and closing device is located on the outlet pipe and is connected to the pneumatic switching device via the negative pressure pipe. The float is movably connected within the collection well and controls the switching state of the pneumatic switching device. When the float rises to its upper limit, the pneumatic switching device switches from being connected to the atmosphere to a negative pressure state, and the pneumatic opening and closing device changes from a closed state to an open state. When the float descends to its lower limit, the pneumatic switching device switches from a negative pressure state to being connected to the atmosphere, and the pneumatic opening and closing device changes from an open state to a closed state.
[0007] By adopting the above technical solution, through the linkage between the float and the gas circuit, the valve state is switched only when the liquid level reaches the upper or lower limit, which greatly reduces the frequency of valve opening and closing and reduces the possibility of frequent start-up and shutdown of negative pressure wells.
[0008] Preferably, a lifting rod is slidably connected inside the collection well. Abutment blocks are provided at both ends of the lifting rod along its length. A float is slidably connected to the lifting rod and positioned between the two abutment blocks. A limiting block is provided on the lifting rod. A first limiting groove and a second limiting groove, which can cooperate with the limiting blocks, are respectively opened inside the collection well. The first limiting groove and the second limiting groove are connected. When the float moves upward, it moves to abut against the upper abutment block and moves the abutment block upward together until the limiting block cooperates with the first limiting groove. When the float moves downward, it abuts against the lower abutment block and moves the abutment block downward together until the limiting block cooperates with the second limiting groove.
[0009] By adopting the above technical solution, the lifting rod provides vertical sliding guidance for the float; the abutment block cooperates with the limiting groove to ensure accurate positioning of the float when triggering air path switching; the upper and lower abutment blocks limit the range of float movement to prevent excessive movement and damage to components, while the cooperation of the limiting block and the limiting groove stably transmits the float's movement to the air path switching device. The float drives the lifting rod to move through the abutment block, converting buoyancy changes into mechanical displacement to ensure the stability of air path switching; the float moves upward, abutting the upper abutment block, pushing the lifting rod upward until the limiting block engages with the first limiting groove, fixing the lifting rod's position and triggering air path switching; the float moves downward, abutting the lower abutment block, pulling the lifting rod downward until the limiting block engages with the second limiting groove, fixing the lifting rod's position, and the air path switching returns to the initial state.
[0010] Preferably, the float is provided with a counterweight.
[0011] By adopting the above technical solution, the counterweight increases the overall weight of the float, allowing for adjustment of the balance between buoyancy and gravity according to actual needs. This enables the float to accurately trigger its action at specific water levels, adapting to different drainage volumes or water quality environments. Appropriate counterweighting can prevent the float from malfunctioning due to water flow fluctuations or slight water level changes, improving system stability. The counterweight adjusts the float's suspension state in the water by changing its weight; when the counterweight is increased, the float requires greater buoyancy to rise to its upper limit; when the counterweight is decreased, the float becomes more sensitive to water level changes, triggering its action even at lower water levels.
[0012] Preferably, the limiting block is slidably connected to the lifting rod, and the lifting rod is provided with a spring. The two ends of the spring abut against the limiting block and the lifting rod respectively, and the spring always drives the limiting block to slide away from the lifting rod.
[0013] By adopting the above technical solution, the spring-driven limiting block always presses firmly against the limiting groove, ensuring that the lifting rod remains in a fixed position after the air circuit switching is triggered, reducing the possibility of loosening due to vibration and other factors. Simultaneously, the spring can buffer the impact force when the float moves, reducing mechanical wear. The sliding connection design of the limiting block facilitates installation and adjustment, while the spring provides elastic support, simplifying the mechanical structure. When the lifting rod moves upward, the limiting block engages with the first limiting groove under the spring's thrust, locking its position. When the lifting rod moves downward, the limiting block compresses the spring, disengaging from the first limiting groove and moving with the lifting rod to the second limiting groove, where the spring again pushes the limiting block into the groove for locking.
[0014] Preferably, the air path switching device includes a housing with an inner cavity, the negative pressure pipeline and the air supply pipeline are respectively connected to the inner cavity, a valve core is slidably connected in the inner cavity, the valve core is provided with a working pipeline, one end of the lifting device is fixedly connected to the valve core, and when the valve core moves to the point where the working pipeline is connected to the negative pressure pipeline, the pneumatic opening and closing device is in the open state.
[0015] By adopting the above technical solution, the valve core slides within the housing cavity, connecting or disconnecting with the negative pressure pipeline via the working pipeline, achieving rapid switching of the air circuit with sensitive response. The valve core is directly connected to the lifting rod, resulting in a short mechanical transmission path and low energy loss, ensuring the timeliness and accuracy of air circuit control. When the float triggers the lifting rod to move upward, it moves the valve core upward, connecting the working pipeline with the negative pressure pipeline, opening the negative pressure in the inner cavity, and opening the pneumatic opening and closing device. When the float triggers the lifting rod to move downward, the valve core resets, disconnecting the working pipeline from the negative pressure pipeline, opening the inner cavity to the atmosphere, and closing the pneumatic opening and closing device.
[0016] Preferably, the pneumatic opening and closing device includes a valve body and an air bladder. The valve body is fixedly connected to the water outlet pipe. The outer rings at both ends of the air bladder along its axial direction are fixedly connected to the valve body, and the middle section of the air bladder is movably connected to the valve body. The water outlet pipe is connected to the air bladder. The middle section of the air bladder and the inner wall of the valve body together form a cavity. The negative pressure pipe and the vent pipe are respectively connected to the cavity. When the valve body is in the closed state, the circumferential sidewall of the air bladder moves to abut against each other. When the valve body is in the open state, the negative pressure pipe evacuates the cavity, causing the circumferential sidewall of the air bladder to move and separate.
[0017] By adopting the above technical solution, when the air circuit switching device is in a negative pressure state, the negative pressure pipeline evacuates the cavity, and the circumferential sidewalls of the airbag separate under the action of the internal and external air pressure difference, opening the water outlet pipeline; when the air circuit switching device is connected to the atmosphere, the air pressure inside the cavity recovers, the circumferential sidewalls of the airbag abut against each other, and the water outlet pipeline closes. The airbag can deform under the action of negative pressure and air pressure, thereby realizing the automatic opening and closing of the water outlet pipeline. When the valve body is in the closed state, the circumferential sidewalls of the airbag abut against each other, which can effectively prevent water from flowing through, thus ensuring the sealing of the water outlet pipeline.
[0018] Preferably, the airbag has two sets of reinforcing ribs on its circumferential sidewall, and the two sets of reinforcing ribs are arranged opposite to each other. When the valve body is closed, the two sets of reinforcing ribs move to opposite sides, and when the valve body is opened, the two sets of reinforcing ribs move to opposite sides.
[0019] By adopting the above technical solution, two sets of opposing reinforcing ribs are set on the circumferential sidewall of the airbag, which can improve the structural strength and rigidity of the airbag, making it less prone to damage during frequent deformation and extending the service life of the pneumatic opening and closing device. The setting of the reinforcing ribs can guide the deformation direction of the airbag during opening and closing, so that the two sets of reinforcing ribs move to the opposite side when the valve body is closed and to the opposite side when it is open, ensuring that the deformation of the airbag is more stable and reliable, thereby improving the accuracy and consistency of the opening and closing of the water outlet pipeline.
[0020] The main technical effects of this utility model are reflected in the following aspects:
[0021] 1. This utility model, through the linkage between the float and the gas circuit, switches the valve state only when the liquid level reaches the upper or lower limit, greatly reducing the frequency of valve opening and closing and reducing the possibility of frequent start-up and shutdown of negative pressure wells;
[0022] 2. This utility model incorporates a lifting rod that provides vertical sliding guidance for the float; the abutment block cooperates with the limiting groove to ensure accurate positioning of the float when triggering air path switching; the upper and lower abutment blocks limit the float's movement range to prevent excessive movement and damage to components, while the limiting block and limiting groove work together to stably transmit the float's movement to the air path switching device. The float drives the lifting rod through the abutment block, converting buoyancy changes into mechanical displacement, ensuring the stability of air path switching;
[0023] 3. By setting a counterweight, this utility model increases the overall weight of the float, which can adjust the balance between buoyancy and gravity according to actual needs, so that the float can be accurately triggered at a specific water level, adapting to different drainage volumes or water quality environments. Appropriate counterweight can prevent the float from malfunctioning due to water flow fluctuations or slight water level changes, thus improving system stability. Attached Figure Description
[0024] Figure 1 This is a schematic diagram of the overall structure of an embodiment of this application.
[0025] Figure 2 This is a schematic diagram of the collection well structure in an embodiment of this application.
[0026] Figure 3 It is along Figure 2 Enlarged view of point A in the middle.
[0027] Figure 4 It is along Figure 2 Enlarged view of point B in the middle.
[0028] Figure 5 It is along Figure 2 Enlarged view of point C in the middle.
[0029] Figure 6 This is a schematic diagram of the airbag structure in an embodiment of this application.
[0030] Explanation of reference numerals in the attached drawings: 1. Collection well; 2. Inlet pipe; 3. Outlet pipe; 4. Float; 5. Air circuit switching device; 6. Pneumatic opening and closing device; 7. Negative pressure pipe; 8. Lifting rod; 9. Abutment block; 10. Limiting block; 11. First limiting groove; 12. Second limiting groove; 13. Counterweight; 15. Shell; 16. Inner cavity; 17. Vent pipe; 18. Valve core; 19. Working pipe; 20. Valve body; 21. Cavity; 22. Airbag; 23. Reinforcing rib. Detailed Implementation
[0031] The following is in conjunction with the appendix Figure 1-6 This application will be described in further detail to make the technical solution of this application easier to understand and master.
[0032] This application discloses a negative pressure well based on pneumatic control.
[0033] Reference Figure 1 and Figure 2 This embodiment of a pneumatically controlled negative pressure well includes a collection well 1, with an inlet pipe 2 and an outlet pipe 3 connected to the outside. It also includes a float 4, a gas path switching device 5, and a pneumatic opening and closing device 6. The pneumatic opening and closing device 6 is fixedly connected to the outlet pipe 3 and connected to the gas path switching device 5 via a negative pressure pipe 7. The float 4 is movably connected inside the collection well 1 and controls the switching state of the gas path switching device 5. When the float 4 rises to its upper limit, the gas path switching device 5 changes from being connected to the atmosphere to a negative pressure state, and the pneumatic opening and closing device 6 changes from a closed state to an open state. When the float 4 falls to its lower limit, the gas path switching device 5 changes from a negative pressure state to being connected to the atmosphere, and the pneumatic opening and closing device 6 changes from an open state to a closed state. Through the linkage between the float 4 and the gas path, the valve state is switched only when the liquid level reaches the upper or lower limit, significantly reducing the valve opening and closing frequency and minimizing the possibility of frequent start-up and shutdown of the negative pressure well.
[0034] Reference Figure 2 and Figure 5A counterweight 13 is fixedly connected to the float 4. The counterweight 13 increases the overall weight of the float 4, allowing adjustment of the balance between buoyancy and gravity according to actual needs, enabling the float 4 to accurately trigger its action at a specific water level and adapt to different drainage volumes or water quality environments. Appropriate counterweight can prevent the float 4 from malfunctioning due to water flow fluctuations or slight water level changes, improving system stability. The counterweight 13 adjusts the suspension state of the float 4 in the water by changing its weight; when the counterweight is increased, the float 4 requires greater buoyancy to rise to the upper limit; when the counterweight is decreased, the float 4 is more sensitive to water level changes and can trigger its action at lower water levels.
[0035] Reference Figure 2 and Figure 3 The limiting block 10 is slidably connected to the lifting rod 8. A spring is installed on the lifting rod 8, with its two ends abutting against the limiting block 10 and the lifting rod 8 respectively. The spring always drives the limiting block 10 to slide away from the lifting rod 8. The spring drives the limiting block 10 to always press against the limiting groove, ensuring that the lifting rod 8 remains in a fixed position after the air circuit switching is triggered, reducing the possibility of loosening due to vibration or other factors. At the same time, the spring can buffer the impact force when the float 4 moves, reducing mechanical wear. The sliding connection design of the limiting block 10 facilitates installation and adjustment, and the spring provides elastic support, simplifying the mechanical structure. When the lifting rod 8 moves upward, the limiting block 10 is pushed into the first limiting groove 11 by the spring, locking the position. When the lifting rod 8 moves downward, the limiting block 10 compresses the spring and exits the first limiting groove 11, moving with the lifting rod 8 to the second limiting groove 12, where the spring pushes the limiting block 10 back into the groove to lock it in place.
[0036] Reference Figure 2 and Figure 3 The pneumatic switching device 5 includes a housing 15 with an inner cavity 16. A negative pressure pipeline 7 and a ventilation pipeline 17 are respectively connected to the inner cavity 16. A valve core 18 is slidably connected within the inner cavity 16. A working pipeline 19 is provided on the valve core 18. One end of the valve core 18 is fixedly connected to the valve core 18. When the valve core 18 moves to the point where the working pipeline 19 aligns with the negative pressure pipeline 7, the pneumatic opening and closing device 6 is in the open state. The valve core 18 slides within the inner cavity 16 of the housing 15, connecting or disconnecting with the negative pressure pipeline 7 via the working pipeline 19, achieving rapid pneumatic switching with sensitive response. The valve core 18 is directly connected to the lifting rod 8, resulting in a short mechanical transmission path, low energy loss, and ensuring timely and accurate pneumatic control. When the float 4 triggers the lifting rod 8 to move upward, the valve core 18 moves upward, the working pipeline 19 connects with the negative pressure pipeline 7, the inner cavity 16 is connected to negative pressure, and the pneumatic opening and closing device 6 is opened; when the float 4 triggers the lifting rod 8 to move downward, the valve core 18 is reset, the working pipeline 19 is disconnected from the negative pressure pipeline 7, the inner cavity 16 is connected to the atmosphere, and the pneumatic opening and closing device 6 is closed.
[0037] Reference Figure 2 and Figure 3A lifting rod 8 is slidably connected inside the collection well 1. Abutment blocks 9 are fixedly connected to both ends of the lifting rod 8 along its length. A float 4 is slidably connected to the lifting rod 8 and positioned between the two abutment blocks 9. A limiting block 10 is provided on the lifting rod 8. A first limiting groove 11 and a second limiting groove 12, which can cooperate with the limiting block 10, are respectively opened inside the housing 15. The first limiting groove 11 and the second limiting groove 12 are connected. When the float 4 moves upward, it moves to abut against the upper abutment block 9 and moves the abutment block 9 upward together until the limiting block 10 cooperates with the first limiting groove 11. When the float 4 moves downward, it abuts against the lower abutment block 9 and moves the abutment block 9 downward together until the limiting block 10 cooperates with the second limiting groove 12.
[0038] Reference Figure 2 and Figure 3 The lifting rod 8 provides a vertical sliding guide for the float 4; the abutment block 9 cooperates with the limiting groove to ensure the accurate positioning of the float 4 when triggering the air path switching; the upper and lower abutment blocks 9 limit the movement range of the float 4 to prevent excessive movement of the float 4 from damaging the components, while the limiting block 10 cooperates with the limiting groove to stably transmit the movement of the float 4 to the air path switching device 5. The float 4 drives the lifting rod 8 to move through the abutment block 9, converting the change in buoyancy into mechanical displacement, ensuring the stability of the air path switching; the float 4 moves upward, abuts the upper abutment block 9, pushes the lifting rod 8 upward until the limiting block 10 is engaged in the first limiting groove 11, fixing the position of the lifting rod 8 and triggering the air path switching; the float 4 moves downward, abuts the lower abutment block 9, pulls the lifting rod 8 downward until the limiting block 10 is engaged in the second limiting groove 12, fixing the position of the lifting rod 8, and the air path switching returns to the initial state.
[0039] Reference Figure 4 and Figure 6The pneumatic opening and closing device 6 includes a valve body 20 and an air bladder 22. The valve body 20 is fixedly connected to the water outlet pipe 3. The outer rings at both ends of the air bladder 22 along the axial direction are fixedly connected to the valve body 20, and the middle section of the air bladder 22 is movably connected to the valve body 20. The water outlet pipe 3 is connected to the air bladder 22. The middle section of the air bladder 22 and the inner wall of the valve body 20 together form a cavity 21. The negative pressure pipe 7 and the vent pipe 17 are respectively connected to the cavity 21. When the valve body 20 is in the closed state, the circumferential sidewall of the air bladder 22 moves to abut against each other. When the valve body 20 is in the open state, the negative pressure pipe 7 evacuates the cavity 21, causing the circumferential sidewall of the air bladder 22 to move and separate. When the air circuit switching device 5 is in a negative pressure state, the negative pressure pipeline 7 evacuates the cavity 21. Under the action of the internal and external air pressure difference, the circumferential sidewalls of the airbag 22 separate, and the water outlet pipeline 3 opens. When the air circuit switching device 5 is connected to the atmosphere, the air pressure in the cavity 21 recovers, the circumferential sidewalls of the airbag 22 abut against each other, and the water outlet pipeline 3 closes. The airbag 22 can deform under the action of negative pressure and air pressure, thereby realizing the automatic opening and closing of the water outlet pipeline 3. When the valve body 20 is in the closed state, the circumferential sidewalls of the airbag 22 abut against each other, which can effectively prevent water from flowing through, so as to ensure the sealing of the water outlet pipeline 3.
[0040] Reference Figure 4 and Figure 6 Two sets of reinforcing ribs 23 are provided on the circumferential sidewall of the airbag 22, and the two sets of reinforcing ribs 23 are arranged opposite to each other. When the valve body 20 is closed, the two sets of reinforcing ribs 23 move to the opposite side; when the valve body 20 is opened, the two sets of reinforcing ribs 23 move to the opposite side. The arrangement of two sets of opposite reinforcing ribs 23 on the circumferential sidewall of the airbag 22 can improve the structural strength and rigidity of the airbag 22, making it less prone to damage during frequent deformation and extending the service life of the pneumatic opening and closing device 6. The arrangement of the reinforcing ribs 23 can guide the deformation direction of the airbag 22 during opening and closing, so that the two sets of reinforcing ribs 23 move to the opposite side when the valve body 20 is closed and to the opposite side when it is open, ensuring that the deformation of the airbag 22 is more stable and reliable, thereby improving the accuracy and consistency of the opening and closing of the water outlet pipe 3.
[0041] Reference Figure 1 and Figure 2 Therefore, the workflow of this pneumatically controlled negative pressure well is as follows:
[0042] S1. Wastewater enters the negative pressure collection well 1 through the inlet pipe 2, and the liquid level in the well rises;
[0043] S2. The rise in the well fluid level causes float 4 to rise;
[0044] S3. After the float 4 rises to the upper limit, the air path switching device 5 switches from the state of being connected to the atmosphere to the state of negative pressure.
[0045] S4. The negative pressure pipeline 7 removes the air from the chamber of the pneumatic opening and closing device 6, and the pneumatic opening and closing device 6 changes from the closed state to the open state. Under the negative pressure of the pipeline, the sewage is discharged from the outlet pipeline 3 to the main network.
[0046] S5. Sewage is discharged from the outlet pipe 3, and the liquid level in the well drops;
[0047] S6. Float 4 descends with the well fluid level;
[0048] S7. After the float 4 descends to the lower limit, the air path switching device 5 switches from negative pressure state to atmospheric connection state;
[0049] S8. After the atmosphere is connected, air enters the inner cavity 16 of the pneumatic opening and closing device 6, and the pneumatic opening and closing device 6 changes from the open state to the closed state;
[0050] Water outlet pipe 3 stops drainage pneumatic opening and closing device 6 vent pipe 17 Working process 1-8 is one working cycle.
[0051] Of course, the above are just typical examples of this application. In addition, this application may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed in this application.
Claims
1. A negative pressure well based on pneumatic control, comprising a collecting well (1) provided with a water inlet pipeline (2) and a water outlet pipeline (3) communicating with the outside, characterized in that: It also includes a float (4), an air path switching device (5), and a pneumatic opening and closing device (6). The pneumatic opening and closing device (6) is installed on the water outlet pipe (3). The pneumatic opening and closing device (6) and the air path switching device (5) are connected through a negative pressure pipe (7) and a ventilation pipe (17). The float (4) is movably connected in the collection well (1). The float (4) is used to control the switching state of the air path switching device (5). When the float (4) rises to the upper limit, the air path switching device (5) changes from the state of being connected to the atmosphere to the state of negative pressure, and the pneumatic opening and closing device (6) changes from the closed state to the open state. When the float (4) falls to the lower limit, the air path switching device (5) changes from the state of being connected to the atmosphere to the state of negative pressure, and the pneumatic opening and closing device (6) changes from the open state to the closed state.
2. A negative pressure well based on pneumatic control according to claim 1, characterized in that: A lifting rod (8) is slidably connected inside the collection well (1). Abutment blocks (9) are respectively provided at both ends of the lifting rod (8) along its length. A float (4) is slidably connected to the lifting rod (8) and is located between the two abutment blocks (9). A limiting block (10) is provided on the lifting rod (8). A first limiting groove (11) and a second limiting groove (12) that can cooperate with the limiting block (10) are respectively opened inside the collection well (1). The first limiting groove... (11) Connected to the second limiting groove (12), when the float (4) moves upward, the float (4) moves to abut against the upper abutment block (9) and drives the abutment block (9) to move upward together to the limiting block (10) to cooperate with the first limiting groove (11). When the float (4) moves downward, the float (4) abuts against the lower abutment block (9) and drives the abutment block (9) to move downward together to the limiting block (10) to cooperate with the second limiting groove (12).
3. A negative pressure well based on pneumatic control according to claim 2, characterized in that: The float (4) is equipped with a counterweight (13).
4. A negative pressure well based on pneumatic control according to claim 2, characterized in that: The limiting block (10) is slidably connected to the lifting rod (8). The lifting rod (8) is provided with a spring. The two ends of the spring abut against the limiting block (10) and the lifting rod (8) respectively. The spring always drives the limiting block (10) to slide away from the lifting rod (8).
5. A negative pressure well based on pneumatic control according to claim 2, characterized in that: The air path switching device (5) includes a housing (15) with an inner cavity (16). The negative pressure pipeline (7) and the air passage (17) are respectively connected to the inner cavity (16). A valve core (18) is slidably connected in the inner cavity (16). A working pipeline (19) is provided on the valve core (18). One end of the lifting device is fixedly connected to the valve core (18). When the valve core (18) moves to the working pipeline (19) and connects with the negative pressure pipeline (7), the pneumatic opening and closing device (6) is in the open state.
6. A negative pressure well based on pneumatic control according to claim 1, characterized in that: The pneumatic opening and closing device (6) includes a valve body (20) and an air bladder (22). The valve body (20) is fixedly connected to the water outlet pipe (3). The outer rings of both ends of the air bladder (22) in the axial direction are fixedly connected to the valve body (20), and the middle section of the air bladder (22) is movably connected to the valve body (20). The water outlet pipe (3) is connected to the air bladder (22). The middle section of the air bladder (22) and the inner wall of the valve body (20) together form a cavity (21). The negative pressure pipe (7) and the ventilation pipe (17) are respectively connected to the cavity (21). When the valve body (20) is in the closed state, the circumferential sidewall of the air bladder (22) moves to abut against each other. When the valve body (20) is in the open state, the negative pressure pipe (7) evacuates the cavity (21), causing the circumferential sidewall of the air bladder (22) to move and separate.
7. A negative pressure well based on pneumatic control according to claim 6, characterized in that: The airbag (22) has two sets of reinforcing ribs (23) on its circumferential sidewall, and the two sets of reinforcing ribs (23) are arranged opposite to each other. When the valve body (20) is closed, the two sets of reinforcing ribs (23) move toward the opposite side. When the valve body (20) is opened, the two sets of reinforcing ribs (23) move toward the opposite side.