Drainage pipeline flow monitoring device and method

Abstract

The invention provides a drainage pipeline flow monitoring device and method, the device comprises a plugging system, a water pumping system and a monitoring system, the plugging system is used for plugging upstream incoming water, the water pumping system is used for lifting the incoming water to the monitoring system, and the monitoring system is used for monitoring real-time flow; the plugging system comprises an annular water inlet and a water inlet pipe, one end of the water inlet pipe is connected with the water inlet, the other end of the water inlet pipe is connected with the water inlet end of a hollow air bag through a connecting flange, and an air bag hollow pipe penetrates through the hollow air bag. The air pressure of the hollow air bag is controlled. By means of the system device, non-full flow in a drainage pipeline can be converted into pressure flow, then the electromagnetic flow meter is used for flow monitoring, and compared with an ultrasonic Doppler flow meter, a more accurate monitoring result can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of municipal drainage pipe networks and relates to a drainage pipe flow monitoring device and method. Background Art

[0002] Ultrasonic Doppler flowmeter is a flow monitoring device widely used in drainage pipe flow measurement. Its principle is to analyze the average flow velocity of the hydraulic section of the drainage pipe based on the ultrasonic frequency shift effect. At the same time, it is equipped with a liquid level sensor to calculate the hydraulic section area through liquid level monitoring. Finally, the pipe flow is measured online through the area-velocity method. It is usually suitable for non-full flow and large-diameter drainage pipe flow monitoring. However, in actual projects, the Doppler ultrasonic flowmeter probe is easy to be polluted and easily affected by water flow impact in the drainage pipe, resulting in a large deviation between its actual monitoring data and the actual data. In addition, the ultrasonic flowmeter probe needs regular operation and maintenance, and the purchase and operation costs are high. The electromagnetic flowmeter mainly detects the pressure pipe flow based on the electromagnetic induction method. Its flow monitoring accuracy is usually high, especially for rainwater and sewage water bodies containing particulate pollutants. The equipment structure is simple and the purchase and operation costs are significantly lower. Summary of the invention

[0003] The purpose of the present invention is to provide a drainage pipe flow monitoring device and method to address the defects of the prior art. The present invention is mainly based on a blocking system, a pumping system and a monitoring system, which can realize temporary and accurate detection of drainage pipe flow data. At the same time, based on the drainage pipe liquid level-flow analysis, the drainage pipe flow can be deduced based on the liquid level monitoring data.

[0004] In a first aspect of the present invention, a drainage pipe flow monitoring device is provided, comprising a blocking system, a pumping system and a monitoring system, wherein the blocking system is used to block the upstream water in the drainage pipe, the pumping system is used to lift the water in the drainage pipe to the monitoring system so that all the upstream water enters the monitoring system through the pumping system, and the monitoring system is used to monitor the real-time flow; wherein,

[0005] The sealing system includes an annular water inlet and a water inlet pipe. One end of the water inlet pipe is connected to the water inlet, and the other end is connected to the water inlet end of the hollow balloon through a connecting flange. An airbag hollow tube runs through the middle of the hollow balloon. An air pipe interface is provided on one side of the water outlet end of the hollow balloon. The air pipe interface is connected to the air pipe, and the upper end of the air pipe is connected to the air pump for controlling the air pressure of the hollow balloon.

[0006] Preferably, the pumping system includes a water inlet connecting pipe, a water pump, a cable and a water outlet connecting pipe. The two ends of the water inlet connecting pipe are respectively connected to the water outlet end of the airbag hollow tube and the water inlet end of the water pump through connecting flanges. The water pump is used to lift the water in the drainage pipe to the ground monitoring system. The cable connects the distribution box and the generator to power the water pump. The water outlet connecting pipe is used to transport the water output from the water pump to the ground monitoring system.

[0007] Preferably, the monitoring system includes a valve, a flowmeter inlet pipe, an electromagnetic flowmeter, a flowmeter outlet pipe, a drain pipe and a liquid level meter. The drain pipe is used to discharge the water after detection. The liquid level meter is installed at the center of the bottom of the straight section of the drainage pipe downstream of the drain pipe outlet inspection well to detect the liquid level in the pipeline. The valve is connected between the outlet connecting pipe and the flowmeter inlet pipe, the electromagnetic flowmeter is connected between the flowmeter inlet pipe and the flowmeter outlet pipe, and the drain pipe is connected to the flowmeter outlet pipe.

[0008] Preferably, the plugging system, pumping system and monitoring system parts are installed in a mobile engineering vehicle, and the air pump, power distribution cabinet, generator, valve, electromagnetic flowmeter, flowmeter water inlet pipe and flowmeter water outlet pipe are all fixedly installed in the engineering vehicle.

[0009] A second aspect of the present invention provides a drainage pipe flow monitoring method, using a drainage pipe flow monitoring device as described in any one of the above, including a temporary monitoring stage and a long-term monitoring stage, wherein the temporary monitoring stage specifically includes the following steps:

[0010] S1 point selection: Combined with the flow monitoring needs, the municipal drainage pipes to be monitored are preliminarily explored, and the monitoring positions are selected according to the following requirements: the maximum fullness of the pipeline liquid level on a sunny day at the monitoring location does not exceed 75%; the pipeline at the monitoring location is straight, and there are no branch pipes connected to the inspection well where the water pump is to be placed and the two consecutive inspection wells downstream; there is no external water infiltration caused by hidden branch pipe connections or pipeline damage in the pipeline between the two consecutive inspection wells downstream, and the hydraulic elements of the entire pipeline section of the two consecutive inspection wells downstream are consistent;

[0011] S2 system equipment selection and assembly: Obtain the pipe diameter D, slope i, burial depth h and basic pipe information of the monitoring pipe section according to the drainage drawings, calculate the flow rate when the pipe is 75% full as the maximum flow rate of the water pump, use the depth of the inspection well M1 as the required head of the water pump, and select the water pump so that the flow monitoring upper limit of the electromagnetic flowmeter is higher than the flow value when the pipe is 75% full;

[0012] S3 On-site installation: The required equipment should be collected by a special engineering vehicle and transported to the monitoring point. Before monitoring, the pipe sections of inspection wells M1 and M2 should be fenced off corresponding to the municipal roads and the parking range of engineering vehicles. During on-site installation, first place all the connected plugging system, pumping system and monitoring system accessories on the ground, and adjust the valves, power supply and air pump to the closed state. Then install a triangular crane above the wellhead of inspection well M1, hoist the hollow bag and water pump to the bottom of inspection well M1, and then use the hook to adjust the placement of the hollow bag so that it is completely placed at the bottom of the upstream pipeline of inspection well M1. Finally, place the outlet end of the drain pipe in the downstream inspection well M2.

[0013] S4 system start-up: First, turn on the mobile power supply in the engineering vehicle, start the air pump through the distribution box to inflate the hollow bag, stop inflating when the upstream pipeline of the inspection well M1 is completely blocked, open the valve to the maximum opening, start the water pump, and the drain pipe starts to drain water;

[0014] S5 Data Observation: During the monitoring process, observe the water inlet pipe of the flow meter. The valve opening degree should be adjusted to keep the water inlet pipe just full at all times to ensure accurate monitoring by the electromagnetic flow meter. During the monitoring process, set the flow and liquid level data reading interval according to the monitoring requirements, and read the electromagnetic flow meter readings regularly to complete temporary monitoring of the instantaneous flow in the drainage pipe.

[0015] S6 Temporary monitoring system removal: After obtaining sufficient data, the plugging system, pumping system and monitoring system can be removed and kept, and the liquid level monitoring device can be retained for liquid level monitoring

[0016] Preferably, the long-term monitoring phase includes:

[0017] Step 1 Liquid level-flow relationship analysis: Input the measured drainage pipe liquid level y and flow Q data into the data analysis software Origin, take the liquid level y as the independent variable and the flow Q as the dependent variable, use the nonlinear curve fitting tool, and input the following two fitting formulas:

[0018]

[0019]

[0020] Where: Q is the flow rate in the pipe, i is the pipe slope, D is the pipe diameter, n is the pipe roughness coefficient, is the angle from the center of the pipe to the two ends of the liquid surface line, and y is the liquid level in the pipe;

[0021] The pipe diameter D and slope i value of the monitoring point are iteratively calculated to obtain the fitted yQ curve and n value, and the liquid level-flow relationship of the monitoring point can be obtained, which is expressed as follows:

[0022]

[0023] θ=2cos -1 (1-6.73y) (4);

[0024] Step 2 Analysis of long-term monitoring data: During long-term monitoring, by substituting the acquired actual liquid level y monitoring data into the liquid level-flow relationship, the flow value represented by the liquid level can be analyzed to analyze and judge the pipeline operation status.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a drainage pipe flow monitoring device and method. Through this system device, the non-full flow in the drainage pipe can be converted into a pressurized flow, and then an electromagnetic flowmeter is used to monitor the flow. Compared with the ultrasonic Doppler flowmeter, the electromagnetic flowmeter can obtain more accurate monitoring results in principle.

[0027] The present invention forms a low-cost long-term flow monitoring method. The use cost of the electromagnetic flowmeter is significantly lower than that of the ultrasonic Doppler flowmeter. Based on the liquid level-flow relationship analysis method of the present invention, it is possible to use liquid level meter monitoring instead of flow meter monitoring during long-term monitoring, and the flow analysis of the monitoring point can also be achieved, which can greatly reduce the investment cost and subsequent operation and maintenance cost of the flow monitoring equipment.

[0028] The present invention forms a vehicle-mounted flow monitoring system device with high flexibility, simple operation and convenient operation and maintenance. The main accessories of this system are commonly seen on the market. Each professional operation and maintenance unit of the pipeline network can simply purchase them or use existing drainage equipment and engineering vehicles for modification. In addition, each accessory is easy to operate and does not require complex professional operation and maintenance. It has the advantages of high work efficiency and convenient operation and maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the system arrangement in the temporary monitoring stage of the present invention.

[0030] Figure 2 It is a schematic diagram of the system layout in the medium and long-term monitoring stage of the present invention.

[0031] Figure 3 The liquid level and flow rate data monitored and obtained in one embodiment of the present invention.

[0032] Figure 4 This is a screenshot of parameter settings for an embodiment of the present invention.

[0033] Figure 5 The figure is a schematic diagram of a calculation process of an embodiment of the present invention.

[0034] Figure 6This is a liquid level curve diagram obtained by fitting in an embodiment of the present invention.

[0035] In the figure: 1. Sealing system; 2. Pumping system; 3. Monitoring system; 101. Water inlet; 102. Water inlet pipe; 103. Connecting flange; 104. Hollow bag; 105. Air bag hollow tube; 106. Air pipe interface; 107. Air pipe; 108. Air pump; 201. Water inlet connecting pipe; 202. Water pump; 203. Cable; 204. Distribution box; 205. Generator; 206. Water outlet connecting pipe; 301. Valve; 302. Flow meter water inlet pipe; 303. Electromagnetic flow meter; 304. Flow meter water outlet pipe; 305. Drain pipe; 306. Liquid level meter. DETAILED DESCRIPTION

[0036] In order to enable those skilled in the art to better understand the technical solution of the present invention, the preferred implementation scheme of the present invention is described below in conjunction with specific embodiments. However, it should be understood that the drawings are only used for exemplary descriptions and cannot be understood as limitations on this patent; in order to better illustrate this embodiment, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted; the positional relationship described in the drawings is only used for exemplary descriptions and cannot be understood as limitations on this patent.

[0037] As an embodiment of the present invention, see the attached Figure 1-Figure 3 This embodiment provides a drainage pipe flow monitoring device, including a blocking system 1, a pumping system 2 and a monitoring system 3. The blocking system 1 is used to block the upstream water in the drainage pipe, and the pumping system 2 is used to lift the water in the drainage pipe to the monitoring system 3 to monitor the flow, so that all the upstream water enters the monitoring system 3 through the pumping system 2. The monitoring system 3 is used to monitor the real-time flow; wherein,

[0038] The plugging system 1 includes an annular water inlet 101 and a water inlet pipe 102. The water inlet 101 is made of metal and has a certain counterweight to ensure that the water inlet will not float in the water during use. A filter screen is installed in the middle to prevent debris with larger particle sizes from entering the system. One end of the water inlet pipe 102 is connected to the water inlet 101, and the other end is connected to the water inlet end of the hollow balloon 104 through a connecting flange 103. The hollow balloon 104 is a conical rubber balloon with a balloon hollow tube 105 running through the middle of the balloon, which can play a role in The drainage pipe is blocked, and the upstream water is prevented from flowing to the downstream through the drainage pipe, and the water can only be drawn into the water pump 202 through the airbag hollow tube 105. The airbag hollow tube 105 should be made of PE material and is tightly sealed with the outer surface of the airbag hollow tube 105 to avoid water leakage or air leakage during use. An air pipe interface 106 is provided on one side of the water outlet end of the hollow bag 104, and the air pipe interface 106 is connected to the air pipe 107. The upper end of the air pipe 107 is connected to the air pump 108, which is used to control the air pressure of the hollow bag 104.

[0039] Specifically, in the above embodiment, the pumping system 2 includes an inlet connecting pipe 201, a water pump 202, a cable 203 and an outlet connecting pipe. The inlet connecting pipe 201 is made of a hose to prevent the blocking system 1 and the pumping system 2 from being unable to dock due to the fluctuation of the bottom elevation of the well when the well bottom elevation fluctuates. The two ends of the inlet connecting pipe 201 are respectively connected to the outlet end of the airbag hollow tube 105 and the inlet end of the water pump 202 through connecting flanges. The water pump 202 is used to lift the water in the drainage pipe to the monitoring system 3 on the ground. The water pump 202 should have a head and maximum flow rate that are suitable for the use scenario of the detected drainage pipe, so that all instantaneous water upstream of the drainage pipe can be lifted to the monitoring system 3 to ensure that the flow monitoring result is accurate. The cable 203 is connected to the distribution box 204 and the generator 205 for powering the water pump 202. The outlet connecting pipe 206 is used to transport the water output from the water pump 202 to the monitoring system 3 on the ground.

[0040] Specifically, the monitoring system 3 includes a valve 301, a flow meter water inlet pipe 302, a flow meter water outlet pipe 304, a drain pipe 305 and a liquid level meter 306. The valve 301 is connected to the water outlet connecting pipe 206 and is used to adjust the flow capacity of the monitoring system or stop the water outlet of the system in an emergency. A butterfly valve or a ball valve can be used. The flow meter water inlet pipe 302 and the flow meter water outlet pipe 304 should be made of hard materials that can be used as pressure pipes, and the length should meet the length requirements of the two straight pipe sections before and after the electromagnetic flow meter 303 used to ensure the stability of the water inlet flow of the electromagnetic flow meter 303. To ensure the accuracy of flow monitoring and facilitate the water volume entering the pipe, the flow meter inlet pipe 302 should be a transparent PVC pipe, the outlet pipe can be a PE pipe or a steel pipe, the drain pipe 305 is used to discharge the water after detection, and the liquid level meter 306 is installed at the center of the bottom of the straight section of the drainage pipe downstream of the outlet inspection well of the drain pipe 305 to detect the pipeline liquid level; the valve 301 is connected between the outlet connecting pipe 206 and the flow meter inlet pipe 302, the electromagnetic flowmeter is connected between the flow meter inlet pipe 302 and the flow meter outlet pipe 304, and the drain pipe 305 is connected to the flow meter outlet pipe 304.

[0041] In some preferred embodiments, please refer to the attached Figure 1 The plugging system 1, the pumping system 2 and the monitoring system 3 are installed in a mobile engineering vehicle. The air pump 108, the power distribution cabinet 204, the generator 205, the valve 301, the electromagnetic flowmeter 303, the flowmeter inlet pipe 302 and the flowmeter outlet pipe 304 are all fixedly installed in the engineering vehicle.

[0042] In some preferred embodiments, see the attached Figure 1 This embodiment provides a drainage pipe flow monitoring method, using a drainage pipe flow monitoring device according to any one of claims 1 to 4, including a temporary monitoring stage and a long-term monitoring stage, wherein the temporary monitoring stage specifically includes the following steps:

[0043] S1 point selection: Combined with the flow monitoring needs, the municipal drainage pipeline to be monitored is preliminarily explored, and the monitoring location is selected according to the following requirements: (1) The maximum fullness of the pipeline liquid level on a sunny day at the monitoring location does not exceed 75%; (2) The pipeline at the monitoring location is straight, and there are no branch pipes connected to the inspection well M1 where the water pump is to be placed and the two consecutive inspection wells M2 and M3 downstream; (3) There is no external water infiltration caused by hidden branch pipes or pipeline damage in the pipeline between the two consecutive inspection wells M2 and M3 downstream, and the hydraulic elements of the entire pipeline of the two consecutive inspection wells M2 and M3 downstream are consistent; (4) There must be no siltation in the pipeline and inspection wells within the range of M1 to M3. If there is siltation, it should be flushed in advance;

[0044] S2 System Equipment Selection and Assembly: Obtain the pipe diameter D, slope i, buried depth h and basic pipe information of the monitoring pipe section according to the drainage drawings, calculate the flow rate when the pipe is 75% full as the maximum flow rate of the water pump 202, use the depth of the inspection well M1 as the required lift of the water pump, select the water pump 202, and make the flow monitoring upper limit of the electromagnetic flowmeter 303 higher than the flow value when the pipe is 75% full;

[0045] S3 On-site installation: The required equipment should be collected by a special engineering vehicle and transported to the monitoring point. Before monitoring, the municipal roads and the parking range of engineering vehicles should be fenced off for the pipe sections of the inspection well M1 and inspection well M2. During on-site installation, first place all the connected accessories of the plugging system 1, pumping system 2 and monitoring system 3 on the ground, among which the valve 301, power supply 204 and air pump 108 are all adjusted to the closed state. Then install a triangular crane above the wellhead of the inspection well M1, hoist the hollow bag 104 and water pump 202 to the bottom of the inspection well M1, and then use the hook to adjust the placement of the hollow bag 104 so that it is completely placed at the bottom of the upstream pipeline of the inspection well M1. Finally, place the outlet end of the drain pipe 305 in the downstream inspection well M2.

[0046] S4 system start: first turn on the mobile power supply in the engineering vehicle, start the air pump 108 through the distribution box 204 to inflate the hollow bag 104, stop inflating when the upstream pipeline of the inspection well M1 is completely blocked, open the valve 301 to the maximum opening, start the water pump 202, and the drain pipe 305 starts to drain water;

[0047] S5 Data observation: During the monitoring process, observe the flow meter water inlet pipe 302. The opening degree of the valve 301 should be adjusted to keep the water inlet pipe 302 in a state of just full flow, so as to ensure the accurate monitoring of the electromagnetic flow meter 303. During the monitoring process, set the flow and liquid level data reading interval according to the monitoring requirements, and read the reading of the electromagnetic flow meter 303 at regular intervals to complete the temporary monitoring of the instantaneous flow of the drainage pipe.

[0048] S6 Dismantling of temporary monitoring system: After obtaining sufficient data, the plugging system 1, the pumping system 2 and the monitoring system 3 can be dismantled and kept, and the liquid level monitoring device 306 is retained for liquid level monitoring.

[0049] In some preferred embodiments, the long-term monitoring phase includes:

[0050] Step 1 Liquid level-flow relationship analysis: Input the measured drainage pipe liquid level y and flow Q data into the data analysis software Origin, take the liquid level y as the independent variable and the flow Q as the dependent variable, use the nonlinear curve fitting tool, and input the following two fitting formulas:

[0051]

[0052]

[0053] Where: Q is the flow rate in the pipe, i is the pipe slope, D is the pipe diameter, n is the pipe roughness coefficient, is the angle from the center of the pipe to the two ends of the liquid surface line, and y is the liquid level in the pipe;

[0054] The monitoring status during the long-term monitoring phase is as follows: Figure 2 As shown, the pipe diameter D and slope i value of the monitoring point are calculated after iteration, and the fitting yQ curve and n value are obtained, and the liquid level-flow relationship of the monitoring point can be obtained;

[0055] Step 2 Analysis of long-term monitoring data: During long-term monitoring, by substituting the acquired actual liquid level y monitoring data into the liquid level-flow relationship, the flow value represented by the liquid level can be analyzed to analyze and judge the pipeline operation status.

[0056] The determination coefficient R in the fitting result report can be generated according to the Origin software 2 , determine the deviation between the fitted level-flow relationship and the measured value: generally 0≤R 2 ≤1, R 2 The closer it is to 1, the higher the goodness of fit, and the more consistent the fitted level-flow relationship is with the actual measurement.

[0057] The monitoring method of the present invention is analyzed and explained below with reference to specific cases.

[0058] In a certain implementation case, the drainage pipe is a HDPE double-wall corrugated pipe with a pipe diameter D of DN300 (actual inner diameter is 297mm) and a slope i of 5‰. Through temporary monitoring, the pipe flow rate Q corresponding to different measured liquid levels y when the liquid level y in the pipe is within the range of 30 to 110mm is obtained, with a total of 20 sets of data. Open the Origin software, create a new worksheet, and enter the liquid level and flow data into the X and Y columns respectively, such as Figure 3 As shown, open the nonlinear curve fitting tool, select New in the function type, open the fitting function generator, define the independent and dependent variables as y and Q, the parameter as n, the constants as D and i, and enter the formula 2 represented by θ in the function body and substitute it into the formula 1 (i.e.

[0059] Q=D^2*i^0.5*(2*acos(1-2*y / D)-sin(2*acos(1-2*y / D)))*(D*(1-sin(2*acos(1-2*y / D)) / 2 / acos(1-2*y / D)) / 4)^(2 / 3) / 8 / n*3600)(Q unit is m 3 / h, y and D are in m), set the initial value of n to 0.095, and the range is 0≤n≤0.02, such as Figure 3 As shown, select the newly created function for fitting and generate the fitting results and images as shown in Figure 5 and Figure 6 As shown, the fitting status is successful, R 2 The fitting effect is good, and the fitting value n is 0.01177. Substituting the actual pipe diameter D, slope i and the fitted n value of the monitoring point into formula 1, the liquid level-flow relationship of the monitoring point can be obtained as follows:

[0060]

[0061] θ=2cos -1 (1-6.73y) (4);

[0062] In the subsequent long-term monitoring process, the measured liquid level y at the monitoring point is substituted into equations 3 and 4 to obtain the corresponding flow data. For example, in this implementation case, according to the monitoring data of the liquid level meter at the monitoring point, the liquid level y = 0.105m at a certain moment, and after substituting it into the equation, the corresponding flow rate Q in the pipe should be 71.44m 3 / h.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A drainage pipe flow monitoring device, characterized in that: The invention comprises a blocking system (1), a pumping system (2) and a monitoring system (3), wherein the blocking system (1) is used to block the upstream water in the drainage pipe, the pumping system (2) is used to lift the water in the drainage pipe to the monitoring system (3), so that all the upstream water enters the monitoring system (3) through the pumping system (2), and the monitoring system (3) is used to monitor the real-time flow rate; wherein: The blocking system (1) comprises an annular water inlet (101) and a water inlet pipe (102), one end of the water inlet pipe (102) is connected to the water inlet (101), and the other end is connected to the water inlet end of the hollow bag (104) through a connecting flange (103), an air bag hollow pipe (105) runs through the middle of the hollow bag (104), an air pipe interface (106) is provided on one side of the water outlet end of the hollow bag (104), the air pipe interface (106) is connected to an air pipe (107), and the upper end of the air pipe (107) is connected to an air pump (108) for controlling the air pressure of the hollow bag (104).

2. A drainage pipe flow monitoring device according to claim 1, characterized in that: The water pumping system (2) comprises a water inlet connecting pipe (201), a water pump (202), a cable (203) and a water outlet connecting pipe. The two ends of the water inlet connecting pipe (201) are respectively connected to the water outlet end of the airbag hollow pipe (105) and the water inlet end of the water pump (202) through connecting flanges. The water pump (202) is used to lift the water in the drainage pipe to the monitoring system (3) on the ground. The cable (203) is connected to the distribution box (204) and the generator (205) to supply power to the water pump (202). The water outlet connecting pipe (206) is used to transport the water discharged by the water pump (202) to the monitoring system (3) on the ground.

3. A drainage pipe flow monitoring device according to claim 2, characterized in that: The monitoring system (3) comprises a valve (301), a flow meter water inlet pipe (302), an electromagnetic flow meter (303), a flow meter water outlet pipe (304), a drain pipe (305) and a liquid level meter (306). The drain pipe (305) is used to discharge the water after detection. The liquid level meter (306) is installed at the center of the bottom of the straight section of the drainage pipeline downstream of the water outlet inspection well of the drain pipe (305) and is used to detect the pipeline liquid level. The valve (301) is connected between the water outlet connecting pipe (206) and the flow meter water inlet pipe (302), the electromagnetic flow meter is connected between the flow meter water inlet pipe (302) and the flow meter water outlet pipe (304), and the drain pipe (305) is connected to the flow meter water outlet pipe (304).

4. A drainage pipe flow monitoring device according to claim 3, characterized in that: The plugging system (1), the pumping system (2) and the monitoring system (3) are partially installed in a mobile engineering vehicle, and the air pump (108), the power distribution cabinet (204), the generator (205), the valve (301), the electromagnetic flow meter (303), the flow meter water inlet pipe (302) and the flow meter water outlet pipe (304) are all fixedly installed in the engineering vehicle.

5. A drainage pipe flow monitoring method, characterized in that: The drainage pipe flow monitoring device according to any one of claims 1 to 4 includes a temporary monitoring stage and a long-term monitoring stage, wherein the temporary monitoring stage specifically includes the following steps: S1 point selection: Combined with the flow monitoring needs, the municipal drainage pipeline to be monitored is preliminarily explored, and the monitoring location is selected according to the following requirements: (1) The maximum fullness of the pipeline liquid level at the monitoring location on a sunny day does not exceed 75%; (2) The pipeline at the monitoring location is straight, and there are no branch pipes connected to the inspection well (M1) where the water pump is to be placed and the two consecutive inspection wells (M2 and M3) downstream; (3) There is no external water infiltration caused by hidden branch pipes or pipeline damage in the pipeline between the two consecutive inspection wells (M2 and M3) downstream, and the hydraulic elements of the entire pipeline of the two consecutive inspection wells (M2 and M3) downstream are consistent; S2 system equipment selection and assembly: Obtain the pipe diameter D, slope i, buried depth h and basic pipe material information of the monitoring pipe section according to the drainage drawing, calculate the flow rate when the pipe is full of 75% as the maximum flow rate of the water pump (202), use the depth of the inspection well M1 as the required head of the water pump, select the water pump (202), and make the flow monitoring upper limit value of the electromagnetic flowmeter (303) higher than the flow value when the pipe is full of 75%; S3 On-site installation: The required equipment shall be collected by a special engineering vehicle and transported to the monitoring point. Before monitoring, the pipe sections of the inspection well M1 and inspection well M2 shall be fenced off in accordance with the municipal roads and the parking range of the engineering vehicle. During on-site installation, firstly, all the connected accessories of the plugging system (1), the pumping system (2) and the monitoring system (3) shall be placed on the ground, wherein the valve (301), the power supply (204) and the air pump (108) shall be adjusted to the closed state. Then, a triangular crane shall be installed above the wellhead of the inspection well M1, and the hollow air bag (104) and the water pump (202) shall be hoisted to the bottom of the inspection well M1. Then, the position of the hollow air bag (104) shall be adjusted by using a hook so that it is completely placed at the bottom of the upstream pipeline of the inspection well M1. Finally, the outlet end of the drain pipe (305) shall be placed in the downstream inspection well M2. S4 system start-up: first, turn on the mobile power supply in the engineering vehicle, start the air pump (108) through the distribution box (204) to inflate the hollow bag (104), stop inflating when the upstream pipeline of the inspection well M1 is completely blocked, open the valve (301) to the maximum opening, start the water pump (202), and the drain pipe (305) starts to drain water; S5 Data observation: During the monitoring process, the flow meter water inlet pipe (302) is observed. The opening degree of the valve (301) should be adjusted so that the water inlet pipe (302) is always kept in a state of just full flow, so as to ensure that the electromagnetic flow meter (303) monitors accurately. During the monitoring process, the flow rate and liquid level data reading intervals are set according to the monitoring requirements, and the readings of the electromagnetic flow meter (303) are read regularly, so as to complete the temporary monitoring of the instantaneous flow of the drainage pipe; S6 Dismantling of temporary monitoring system: After obtaining sufficient data, the plugging system (1), the pumping system (2) and the monitoring system (3) can be dismantled and stored, and the liquid level monitoring device (306) is retained for liquid level monitoring.

6. A drainage pipe flow monitoring method according to claim 5, characterized in that: The long-term monitoring phase includes: Step 1 Liquid level-flow relationship analysis: Input the measured drainage pipe liquid level y and flow Q data into the data analysis software Origin, take the liquid level y as the independent variable and the flow Q as the dependent variable, use the nonlinear curve fitting tool, and input the following two fitting formulas: Where: Q is the flow rate in the pipe, i is the slope of the pipe, D is the pipe diameter, n is the roughness coefficient of the pipe, is the angle between the center of the pipe and the two ends of the liquid surface line, and y is the liquid level in the pipe; The pipe diameter D and slope i value of the monitoring point are iteratively calculated to obtain the fitted yQ curve and n value, and the liquid level-flow relationship of the monitoring point can be obtained, which is expressed as follows: θ=2cos -1 (1-6.73y) (4); Step 2 Analysis of long-term monitoring data: During long-term monitoring, by substituting the acquired actual liquid level y monitoring data into the liquid level-flow relationship, the flow value represented by the liquid level can be analyzed to analyze and judge the pipeline operation status.

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