Double-ring multifunctional inspection well for the end of intercepting combined sewer system and its application method

Abstract

The present invention provides a double-ring multifunctional inspection well for the end of an intercepting combined sewer system and an application method, belonging to the technical field of drainage inspection wells. The inspection well includes an inner ring well and an outer ring well arranged in two layers, respectively. The inner ring well is formed by the inner ring well wall, and the outer ring well is formed by the outer ring well wall and the inner ring well wall. The inner ring well wall is provided with a water hole connecting the outer ring well and the inner ring well. The inner ring well is provided with an inner ring well water inlet pipe and an inner ring well water outlet pipe. The outer ring well is provided with a combined water inlet pipe and an overflow water outlet pipe. The water hole is located away from the combined water inlet pipe, and a float valve is provided on the side of the water hole facing the outer ring well. The present invention divides the multifunctional inspection well into two parts: the outer ring well is the water inlet area, the overflow area, and the energy dissipation area, and the inner ring well is the connection area, the interception area, and the water outlet area. The inspection well integrating multiple functions can effectively prevent flooding, save space, and reduce investment.

Description

Technical Field

[0001] The present invention relates to the technical field of municipal drainage, and in particular to a double-ring multifunctional inspection well for the end of an intercepting combined sewer system and an application method thereof. Background Art

[0002] In the current traditional intercepting combined sewer system, when the intercepting pipe is connected to the drainage main, due to the deep burial depth of the main, the height difference between the intercepting pipe and the drainage main is large. Therefore, the system first sets up an intercepting well, then a drop well, and finally a three-way connection well to connect the drainage main and the branch pipe connected to the intercepting pipe. This method not only increases investment and floor space, but also creates difficulties in the project implementation stage and finally causes inconvenience to management personnel in the operation stage. Summary of the Invention

[0003] The present invention provides a double-ring multifunctional inspection well for the end of an intercepting combined sewer system and an application method. This solves the problem that it is difficult to add multiple inspection wells in a narrow area when the end of the intercepting combined sewer system intersects with the main pipe, and sequentially completes the three functions of interception, water drop, and connection. The inspection wells have large floor space, increase project investment, and affect subsequent operation and maintenance. By modifying the four-way well, a multifunctional inspection well is created that integrates water inlet, connection, interception, energy dissipation, overflow, water discharge, and mud settling. The technical solution is as follows:

[0004] A double-ring multifunctional inspection well for the end of a cut-off combined sewer system, comprising an inner ring well and an outer ring well arranged in inner and outer layers respectively, the inner ring well being formed by the inner ring well wall, the outer ring well being formed by the outer ring well wall and the inner ring well wall; the inner ring well wall being provided with a water passage connecting the outer ring well and the inner ring well, the inner ring well being provided with an inner ring well water inlet pipe and an inner ring well water outlet pipe, the outer ring well being provided with a relatively arranged combined water inlet pipe and an overflow water outlet pipe, the water passage being located away from the combined water inlet pipe, and a float valve being provided on the side of the water passage facing the outer ring well.

[0005] The water hole is located on the opposite side of the combined water inlet pipe and is lower than the overflow water outlet pipe.

[0006] The water hole is located below the overflow outlet pipe, and the bottom elevation is 70 mm to 120 mm higher than the bottom of the outer ring well.

[0007] The diameter of the inner ring well is determined according to the diameter of the inner ring well outlet pipe, and the bottom elevation of the inner ring well is determined according to the bottom elevation of the inner ring well outlet pipe minus 70mm to 120mm.

[0008] The water inlet direction of the outer ring well is symmetrical to the direction of the water hole and the overflow pipe.

[0009] The outer ring well is a circular inspection well, which is a closed circular well formed by the outer ring well wall and the inner ring well wall; the inner ring well is a cylindrical inspection well, which is a closed cylindrical well formed by the inner ring well wall; the bottom elevation of the outer ring well is consistent with the bottom elevation of the inner ring well, and the diameter of the outer ring well is the diameter of the inner ring well plus 800mm to 1400mm.

[0010] A cover plate and a manhole are set on the top of the outer ring well, and the cover plate is shared with the inner ring well.

[0011] The bottom elevation of the outer ring well is 500mm above the top of the inner ring well outlet pipe. The bottom of the combined water inlet pipe should be higher than the top of the water hole and less than 4000mm. The bottom elevation of the inner ring well is 100mm below the bottom of the inner ring well outlet pipe.

[0012] A method for applying a double-ring multifunctional inspection well at the end of an intercepting combined sewer system. During the dry season, the combined sewage enters the outer ring well, and the water flow impacts the wall of the inner ring well and falls to the bottom of the outer ring well. Part of the kinetic energy of the combined sewage water body is converted into potential energy, causing the liquid level to rise and forming a hydraulic jump; the water body then flows around the outer ring well, flows through the water holes on the wall of the inner ring well, and falls into the inner ring well; the water body and the upstream sewage flowing into the inner ring water inlet pipe merge in the inner ring well, and are discharged together through the inner ring well outlet pipe to the downstream sewage treatment plant.

[0013] During the rainy season, at the beginning of rainfall, the combined sewage enters the outer ring well, then flows around the outer ring well, flows through the water holes on the wall of the inner ring well and falls into the inner ring well. The combined sewage and the upstream combined sewage flowing into the inner ring inlet pipe merge in the inner ring well and are discharged to the downstream sewage treatment plant through the inner ring well outlet pipe.

[0014] In the late stage of rainfall or during heavy rain, the water level in the inner ring well rises, the float valve closes, the combined sewage enters the outer ring well, and then flows around the outer ring well. The water level in the outer ring well rises, and when it rises to the elevation of the overflow outlet pipe, the combined sewage is discharged to the receiving water body through the overflow outlet pipe.

[0015] The dual-ring multifunctional inspection well and its application method for the terminal of an intercepting combined sewer system transform a conventional four-way well into a multifunctional inspection well, achieving the goals of saving space and expediting construction. By providing an inner and outer ring, the integrated inspection well is divided into two parts and incorporates six functions, including water inlet, overflow, energy dissipation, connection, interception, and water outlet. This combines traditional intercepting wells, drop wells, and three-way connection wells into a single inspection well, thereby saving space and reducing investment, providing a preferred solution for construction units.

[0016] The inspection well provided by the present invention also has a sludge settling function. Because the water hole is 100 mm higher than the bottom of the outer ring well, after the combined or sewage inlet pipe enters the outer ring well, impurities can be deposited at the bottom of the outer ring well, playing a sludge settling role and preventing particulate impurities from entering the inner ring well. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 1 is a schematic structural diagram of embodiment 1 of the double-ring multifunctional inspection well for the terminal of the intercepting combined sewer system;

[0018] Figure 2 1 is a top view schematic diagram of embodiment 1 of the double-ring multifunctional inspection well for the end of the intercepting combined sewer system;

[0019] Figure 3 yes Figure 2 Schematic diagram of the right side;

[0020] Figure 4 yes Figure 2 A front view schematic diagram of

[0021] Figure 5 This is a schematic diagram of an application example of the present invention;

[0022] Figure 6 1 is a structural diagram of the float valve;

[0023] Description of the accompanying figures:

[0024] 1-Combined inlet pipe; 2-Overflow outlet pipe; 3-Inner ring well inlet pipe; 4-Inner ring well outlet pipe; 5-Outer ring well wall; 6-Inner ring well wall; 7-Water hole; 8-Outer ring well bottom elevation; 9-Outer ring well; 10-Inner ring well; 11-Float valve; 12-Valve plate; 13-Float; 14-Pendant; 15-Upper slide rail; 16-Lower slide rail; 17-Upper stopper; 18-Lower stopper; 19-First pulley; 20-Second pulley; 21-Third pulley; 22-Traction rope; 23-Pull rope. DETAILED DESCRIPTION

[0025] like Figure 1 and Figure 2 As shown, the double-ring multifunctional inspection well for the end of the intercepting combined sewer system includes an inner ring well 10 and an outer ring well 9 located on the inner and outer layers, respectively. The inner and outer ring wells are connected by a water hole 7. A float valve 11 is provided on the side of the water hole 7 close to the outer ring well 9. The float valve 11 is used to prevent water from the sewage main pipe of the inner ring well 10 from overflowing into the outer ring well 9. Furthermore, the bottom elevation of the outer ring well 9 is consistent with that of the inner ring well 10.

[0026] In one embodiment, the outer ring well 9 is a circular inspection well, a sealed circular well formed by the outer ring well wall 5 and the inner ring well wall 6; the inner ring well 10 is a cylindrical inspection well, a sealed cylindrical well formed by the inner ring well wall 6. In one embodiment, the diameter of the outer ring well 9 is the diameter of the inner ring well 10 plus 1000 mm.

[0027] The outer ring well 9 is provided with a combined water inlet pipe 1 and an overflow water outlet pipe 2. The combined water inlet pipe 1 is used to transport sewage or combined sewage to the outer ring well 9. The combined water inlet pipe 1 is provided on one side of the outer ring well wall 5. The water inlet direction of the combined water inlet pipe 1 can be in any direction according to the needs of the project. The elevation and diameter of the combined water inlet pipe 1 are calculated and valued based on the existing data of the project. An overflow water outlet pipe 2 is provided on the opposite side of the combined water inlet pipe 1. The overflow water outlet pipe 2 is also provided on the outer ring well wall 5. The diameter and elevation of the overflow water outlet pipe 2 are the same as those of the combined water inlet pipe 1.

[0028] The water from the outer ring well 9 enters the inner ring well 10 through the water hole 7 on the inner side of the outer ring well 9. The water hole 7 is set on the inner ring well wall 6 and is located away from the combined inlet pipe 1. The water inlet direction of the outer ring well is arranged symmetrically with the water hole and overflow pipe. In this embodiment 1, the water hole 7 is located on the opposite side of the combined inlet pipe 1 and below the overflow outlet pipe 2. The size of the water hole 7 is calculated based on the interception multiple and the interception flow rate. The bottom elevation of the water hole 7 is 100 mm higher than the bottom of the outer ring well 9.

[0029] During the use of the outer ring well 9, sewage or combined sewage passes through the outer ring well wall 5 and flows into the outer ring well 9 through the pipeline gravity flow. When it just enters, the water flow has a relatively large flow rate. After impacting the inner ring well wall 6, it falls to the bottom of the outer ring well. Part of the kinetic energy of the water body is converted into potential energy, causing the liquid level to rise significantly, forming a water jump, and then it flows around the outer ring well 9 for half a circle, adjusting the water flow state, and flows through the water hole 7 on the inner ring well wall 6 into the inner ring well 10, realizing the waterfall energy dissipation effect.

[0030] The inner ring well 10 is provided with an inner ring well inlet pipe 3 and an inner ring well outlet pipe 4 serving as sewage main pipes. The upstream sewage flowing into the inner ring well inlet pipe 3 is discharged to the downstream through the inner ring well outlet pipe 4. The diameter of the inner ring well 10 is determined according to the diameter of the inner ring well outlet pipe 4, and the bottom elevation of the inner ring well 10 is determined according to the bottom elevation of the inner ring well outlet pipe 4 minus 100 mm.

[0031] The diameter and elevation of the inner ring well water inlet pipe 3, and the diameter and elevation of the inner ring well water outlet pipe 4 are determined according to the actual needs of the project and the elevation of the upstream and downstream water. The inner ring well water inlet pipe 3 is not limited to the direction of the water inlet, and can be arranged symmetrically with the inner ring well water outlet pipe 4, or can be arranged at an obtuse angle. In one embodiment, the outer side of the water hole 7 receives the combined sewage from the outer ring well 9, and the combined sewage enters the inner ring well 10 through the water hole 7, and merges with the upstream sewage flowing into the inner ring well water inlet pipe 3 in the inner ring well, and then is discharged to the urban sewage treatment plant through the inner ring well water outlet pipe 4.

[0032] A float valve 11 is set on the outside of the water hole 7. The size of the float valve 11 is the same as that of the water hole 7. The main function of the float valve 11 is in the rainy season. In the dry season, the float valve 11 is fully open, and the domestic sewage generated by residents enters the inner ring well 10 from the outer ring well 9, and is then discharged to the downstream sewage treatment plant. At the beginning of rainfall, the runoff rainwater generated on the ground carries pollutants such as dust and soil. At this time, the pollution level of combined sewage is high and the rainfall is small. The water levels of the inner ring well 10, the inner ring well inlet pipe 3, and the inner ring well outlet pipe 4 are all low. At this time, the float valve is also in a fully open state. When the rainfall reaches the end, the ground is relatively clean after being washed by rainwater, and the pollution level of combined sewage is low. At this time, the rainfall increases, and the water level of the outer ring well 9 rises until it reaches the conditional water level for the float valve 11 to close. At this time, the water hole 7 is closed, and the relatively clean combined sewage stagnates in the outer ring well 9. The water level of the outer ring well 9 rises, and the overflow outlet pipe 2 comes into play, discharging the relatively clean combined sewage through the overflow outlet pipe 2 to a receiving water body with a certain water environment capacity, thereby avoiding causing the outer ring well to be full of water and then ground flooding.

[0033] Combine Figure 3 and Figure 4 As shown, the bottoms of the inner ring well water inlet pipe 3 and the inner ring well water outlet pipe 4 are higher than the bottom of the inner ring well 10, and the tops of the inner ring well water inlet pipe 3 and the inner ring well water outlet pipe 4 are lower than the bottom of the outer ring well 9. The bottom of the water hole 7 is higher than the bottom of the outer ring well 9, and the top of the water hole 7 is lower than the bottom of the combined water inlet pipe 1 and the overflow water outlet pipe 2. The combined water inlet pipe 1 and the overflow water outlet pipe 2 are at the same height. The outer ring well bottom elevation 8 is above the top of the inner ring well water outlet pipe, and the inner ring well bottom elevation is below the bottom of the inner ring well water outlet pipe.

[0034] The double-ring multifunctional inspection well for the end of the intercepting combined sewer system is divided into two parts by setting an inner ring well and an outer ring well, and has the following functions:

[0035] (1) The combined water inlet pipe first enters the outer ring well 9 according to the direction of the incoming water. After colliding and rubbing with the wall 6 of the inner ring well, it eliminates part of the kinetic energy, realizes the energy dissipation function, and falls into the bottom of the outer ring well 9, completing the water intake function. Then, it flows through the circular channel of the outer ring well 9 to the end water hole 7, thereby eliminating the energy carried by the water body when entering the outer ring well 9 from the combined pipe.

[0036] (2) An overflow outlet pipe 2 with the same diameter and elevation as the combined inlet pipe 1 is set in the outer ring well 9 to realize the overflow function of the multifunctional inspection well during rainfall.

[0037] (3) During the dry season, sewage flows through the water hole 7 and falls into the inner well ring 10. The inner ring well 10 is connected to the inlet and outlet pipes of the drainage main, completing the connection and water outlet functions of the inspection well.

[0038] (4) During the rainy season, the combined sewage is restricted from entering the inner ring well 10 by the action of the float valve 11, thereby achieving the interception function.

[0039] The following examples are provided merely to illustrate the present invention and are not intended to limit the scope of the present invention. It will be apparent to those skilled in the art that other variations or modifications may be made based on the following description. Such obvious variations or modifications arising from the spirit of the present invention are still within the scope of protection of the present invention.

[0040] refer to Figures 1 to 4 As shown, the present invention provides a double-ring multifunctional inspection well for the end of the intercepting combined sewer system. The overall structure is to divide the multifunctional inspection well into an inner ring well and an outer ring well by setting two outer walls. Through clever arrangement and the water retaining weir, water hole, float valve, etc. set in the area, the multifunctional inspection well has six functions including water intake, overflow, energy dissipation, connection, interception and mud sedimentation.

[0041] Two well walls are set up to create different functional areas: the outer ring well is a circular inspection well, and the inner ring well is a cylindrical inspection well. The outer ring well has three functions: water inlet, overflow and energy dissipation. The diameter of the outer ring well is 1000mm. The diameter of the water hole is calculated according to the interception rate. The bottom of the water hole is 100mm higher than the bottom of the outer ring well, acting as a dissipation sill. A cover plate and a manhole are set on the top of the outer ring well, and the cover plate is shared with the inner ring well.

[0042] The bottom elevation of the outer ring well is 500mm above the top of the outlet pipe. The bottom of the combined inlet pipe should be higher than the top of the water hole and less than 4000mm. The elevation of the combined inlet pipe is determined according to the elevation of the incoming water. An overflow outlet pipe of the same diameter and elevation is set on the opposite side of the combined inlet pipe. The inner ring well has three functions: connection, interception, and water discharge. The diameter of the inner ring well should match the corresponding well diameter according to the diameter of the inner ring well outlet pipe. After the combined water falls into the inner ring well through the water hole, it is transferred to the downstream sewage treatment plant through the outlet pipe. The bottom elevation of the inner ring well is 100mm below the bottom of the outlet pipe. A manhole is set at the top of the inner ring well. The inlet and outlet pipes of the inner ring well can be located in any direction and adjusted according to actual conditions. The inlet and outlet pipes of the inner ring well are flat-connected. A float valve of corresponding aperture is set on the outside of the water hole of the inner ring well to control the water level, thereby achieving the purpose of controlling the interception volume.

[0043] Operation of the outer ring well: Sewage or combined sewage flows into the outer ring inspection well through the gravity flow of the pipeline. When it first enters, the water flow has a large flow rate. After impacting the inner ring well wall, it falls to the bottom of the outer ring well. Part of the kinetic energy of the water body is converted into potential energy, causing the liquid level to rise significantly, forming a water jump. Then it flows around the well for half a circle, adjusts the water flow state, and flows through the water hole 50mm above the bottom of the outer ring well into the inner ring well, acting as a force dissipation sill.

[0044] Operation of the inner ring well: During the initial rainfall, highly polluted combined sewage falls through the water holes into the inner ring well. At this time, the float valve is open, and the combined sewage is discharged through the inner ring well outlet pipe to the downstream sewage treatment plant. However, as the rainfall duration increases, the water level in the pipe network continues to rise, and the water level in the outer ring well also increases. At this time, the float valve acts as a flow limiter, preventing the combined sewage from the outer ring well from entering the inner ring well. As a result, the overflow outlet pipe of the outer ring well is discharged to the outside, preventing ground flooding.

[0045] The application method of the double-ring multifunctional inspection well at the end of the intercepting combined sewer system includes the following specific working steps, including both dry season and rainy season:

[0046] During the dry season, sewage enters the outer ring well at a high velocity. It impacts the inner ring well wall and falls to the bottom of the outer ring well. Part of the water's kinetic energy is converted into potential energy, causing the liquid level to rise significantly, forming a hydraulic jump. The water then flows half a circle around the outer ring well, adjusting its flow pattern, and falls through the water holes on the inner ring well wall into the inner ring well. It then merges with the upstream sewage flowing into the inner ring inlet pipe in the inner ring well and is discharged through the inner ring well outlet pipe to the downstream sewage treatment plant.

[0047] During the rainy season: At the beginning of rainfall, the combined sewage enters the outer ring well, then flows half a circle around the outer ring well, adjusting the water flow pattern, flowing through the water holes on the wall of the inner ring well and falling into the inner ring well. It merges with the upstream combined sewage flowing into the inner ring inlet pipe in the inner ring well and is discharged to the downstream sewage treatment plant through the inner ring well outlet pipe. In the later stages of rainfall or during heavy rain, the water level in the outer ring well rises, the float valve closes, and the combined sewage enters the outer ring well, then flows once around the outer ring well. The water level in the outer ring well rises. When it rises to the elevation of the overflow outlet pipe, the combined sewage is discharged through the overflow outlet pipe to the receiving water body.

[0048] It can be seen that the multifunctional inspection well is equipped with two well walls, which divide the multifunctional inspection well into two parts. The outer ring well is the water inlet area, overflow area and energy dissipation area, and the inner ring well is the connection area, interception area and water outlet area. The combined inlet pipe first enters the outer ring inspection well according to the direction of the incoming water, collides and rubs with the inner wall of the inspection well, eliminates part of the kinetic energy, and falls into the bottom of the outer ring well. It then flows through the outer ring well channel for a circle to the end water hole, thereby eliminating the energy carried by the water entering the inspection well from the combined pipe. At the same time, an overflow outlet pipe with the same diameter and elevation as the combined inlet pipe is set in the outer ring well to realize the overflow function of the inspection well during rainfall. After passing through the water hole, the combined inlet flow falls into the inner ring of the inspection well. The inner ring is connected to the inlet and outlet pipes of the drainage main to complete the connection and water outlet functions of the inspection well. In summary, the inspection well integrating multiple functions can effectively prevent flooding, save space, and reduce investment.

[0049] refer to Figure 5As shown, the double-ring multifunctional inspection well for the end of the intercepting combined sewer system provided by the present invention can be set in a position in the intercepting combined sewer system, and can be used for the scenario where a single combined sewer pipe is connected to the drainage network, and can also be used for the scenario where the combined pipe of the entire intercepting combined sewer area is connected to the drainage main of the intercepting combined sewer system.

[0050] like Figure 6 As shown, the structure of the float valve 11 includes a slide rail, a valve plate 12, a float 13 and a pendant 14. Slide rails are provided on the upper and lower sides of the water hole 7. The valve plate 12 can move along the slide rails to block the water outlet 7. One end of the valve plate 12 is connected to the pendant 14 through a pull rope 23, and the other end is connected to the float 13 through a traction rope 22.

[0051] The slide rails include an upper slide rail 15 and a lower slide rail 16. The upper slide rail 15 is installed above the water hole 7, and the lower slide rail 16 is installed below. The upper side of the valve plate 12 is fixedly connected to the upper slider of the upper slide rail 15, and the lower side is fixedly connected to the lower slider of the lower rail 16. Through the two sliders, the valve plate 12 can move along the slide rails, and when it moves to the water hole 7, it can block the water hole 7.

[0052] The valve plate 12 is located on the left side away from the water hole 7 and is connected to the pendant 14 via a pull cord 23. The pendant 14 is a heavy object that can pull the valve plate 12 away from the water hole 7 so that it does not block the water hole 7. On the side near the pendant 14, that is, on the left side of the water hole 7, the upper slide rail 15 is provided with an upper stopper 17, and the lower slide rail 16 is provided with a lower stopper 18. The upper stopper 17 and the lower stopper 18 can limit the leftward movement range of the valve plate 12. Furthermore, the pull cord 23 passes around the first pulley 19, which is mounted on the lower slide rail 16 via a first support rod.

[0053] The valve plate 12 is located near the right side of the water hole 7 and is connected to the buoy 13 via a traction rope 22. A second pulley 20 and a third pulley 21 are provided on the right side of the water hole 7 to limit the traction rope 22. The second pulley 20 and the third pulley 21 are arranged one above the other, and the traction rope 22 passes between the second pulley 20 and the third pulley 21. The second pulley 20 is mounted on the upper slide rail 15 via a second support rod, and the third pulley 21 is mounted on the lower slide rail 16 via a third support rod. The second pulley 20 and the third pulley 21 limit the distance that the valve plate 12 can move to the right.

[0054] When the water level in outer well 9 is low, pendant 14 is heavier than buoy 13. Pendant 14 pulls valve plate 12 leftward, and buoy 13 also moves leftward until valve plate 12 is stopped by upper block 17 and lower block 18. As the water level in outer well 9 rises, buoy 13, affected by buoyancy, pulls valve plate 12 rightward, gradually blocking water hole 7. By adjusting the height of second pulley 20 and third pulley 21, as well as the length of towing rope 22, the initial rise height of the buoy can be adjusted to varying water levels.

[0055] This invention combines traditional intercepting wells, drop wells, and three-way connection wells into a single inspection well, saving space and reducing investment. The energy dissipation effect of the drop well prevents excessively high inflowing water from directly entering the existing well, which could scour downstream pipelines. It also prevents dry season sewage from directly falling into the existing well, which could cause aeration. The interception function also confines the relatively clean combined sewage of the rainy season to the outer ring well, preventing it from entering the inner ring well and causing significant pressure on the water supply and drainage network.

Claims

1. A double-ring multifunctional inspection well for the end of a combined sewer system, characterized by: The sump is a cylindrical manhole that is provided with a plurality of sump tubes, and a plurality of sump tubes that are connected to the sump. The sump tubes are connected to the manholes by a plurality of sump tubes, and a plurality of sump tubes are connected to the manholes by a plurality of sump tubes. The bottom of the inner ring well water inlet pipe and the inner ring well water outlet pipe are higher than the bottom of the inner ring well, the top of the inner ring well water inlet pipe and the inner ring well water outlet pipe are lower than the bottom of the outer ring well, and the bottom of the water hole is higher than the bottom of the outer ring well; the top of the water hole is lower than the bottom of the combined water inlet pipe and the overflow outlet pipe; the combined water inlet pipe and the overflow outlet pipe have the same height, the bottom elevation of the outer ring well is above the top of the inner ring well water outlet pipe, and the bottom elevation of the inner ring well is below the bottom of the inner ring well water outlet pipe. The water hole is located on the opposite side of the combined water inlet pipe and is lower than the overflow outlet pipe.

2. The double-ring multifunctional inspection well for the terminal of the intercepting combined sewer system according to claim 1 is characterized in that: The water hole is located below the overflow outlet pipe, and the bottom elevation is 70mm~120mm higher than the bottom of the outer ring well and meets the equipment installation requirements.

3. The double-ring multifunctional inspection well for the terminal of a intercepting combined sewer system according to claim 1, characterized in that: The diameter of the inner ring well is determined according to the diameter of the inner ring well outlet pipe, and the bottom elevation of the inner ring well is determined according to the bottom elevation of the inner ring well outlet pipe minus 70mm~120mm.

4. The double-ring multifunctional inspection well for the terminal of a intercepting combined sewer system according to claim 1 is characterized in that: The water inlet direction of the outer ring well is symmetrical to the direction of the water hole and the overflow pipe.

5. The double-ring multifunctional inspection well for the terminal of a intercepting combined sewer system according to claim 1 is characterized in that: The outer ring well is a circular inspection well, which is a closed circular well formed by the outer ring well wall and the inner ring well wall; the inner ring well is a cylindrical inspection well, which is a closed cylindrical well formed by the inner ring well wall; the bottom elevation of the outer ring well is consistent with the bottom elevation of the inner ring well, and the diameter of the outer ring well is the diameter of the inner ring well plus 800mm~1400mm.

6. The double-ring multifunctional inspection well for the terminal of a combined sewer system according to claim 1, characterized in that: A cover plate and a manhole are set on the top of the outer ring well, and the cover plate is shared with the inner ring well.

7. The double-ring multifunctional inspection well for the terminal of a intercepting combined sewer system according to claim 1, characterized in that: The bottom elevation of the outer ring well is 500mm above the top of the inner ring well outlet pipe. The bottom of the combined water inlet pipe should be higher than the top of the water hole and less than 4000mm. The bottom elevation of the inner ring well is 100mm below the bottom of the inner ring well outlet pipe.

8. An application method of the double-ring multifunctional inspection well at the end of a combined sewer system as claimed in claim 1, characterized in that: Operation of the outer ring well: Sewage or combined sewage flows into the outer ring inspection well through the pipeline gravity flow. When it first enters, the water has a high flow rate. After impacting the inner ring well wall, it falls to the bottom of the outer ring well. Part of the kinetic energy of the water body is converted into potential energy, causing the liquid level to rise significantly, forming a hydraulic jump. Then, it flows around the well for half a circle, adjusting the water flow pattern, and flows through the water hole 50mm above the bottom of the outer ring well into the inner ring well, acting as a stilling sill. Operation of the inner ring well: At the beginning of rainfall, the highly polluted combined sewage falls into the inner ring well through the water hole. At this time, the float valve is open, and the combined sewage is discharged to the downstream sewage treatment plant through the inner ring well outlet pipe of the inner ring well. As the rainfall duration increases, the water level in the pipe network continues to rise, and the water level in the outer ring well also increases. At this time, the float valve acts as a flow limiter, preventing the combined sewage from the outer ring well from entering the inner ring well, so that the overflow outlet pipe of the outer ring well is discharged to the outside, avoiding ground flooding; During the dry season, the combined sewage enters the outer ring well, and the water flow hits the wall of the inner ring well and falls to the bottom of the outer ring well. Part of the kinetic energy of the combined sewage water body is converted into potential energy, causing the liquid level to rise and forming a hydraulic jump; the water body then flows around the outer ring well, flows through the water holes on the wall of the inner ring well and falls into the inner ring well; the water body and the upstream sewage flowing into the inner ring inlet pipe merge in the inner ring well, and are discharged to the downstream sewage treatment plant through the inner ring well outlet pipe.

9. The application method of the double-ring multifunctional inspection well at the end of the intercepting combined sewer system according to claim 8, characterized in that: During the rainy season, at the beginning of rainfall, the combined sewage enters the outer ring well, then flows around the outer ring well, flows through the water holes on the wall of the inner ring well and falls into the inner ring well. The combined sewage and the upstream combined sewage flowing into the inner ring inlet pipe merge in the inner ring well and are discharged to the downstream sewage treatment plant through the inner ring well outlet pipe. In the late stage of rainfall or during heavy rain, the water level in the inner ring well rises, the float valve closes, the combined sewage enters the outer ring well, and then flows around the outer ring well. The water level in the outer ring well rises, and when it rises to the elevation of the overflow outlet pipe, the combined sewage is discharged to the receiving water body through the overflow outlet pipe.

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