Water supply pressure pipeline leakage point identification method

Abstract

The invention provides a water supply pressure pipeline leakage point identification method comprising the following steps: S1, installing a pressure sensor and a flowmeter on a pipeline, and monitoring pipeline pressure and pipeline flow velocity in real time; s2, calculating the pressure difference between the two pressure sensors according to the pressure values measured by the pressure sensors; s3, whether leakage points exist in the pipeline or not is judged; and S4, establishing a leakage point pressure equation: deltaP leakage = Pfront-Prear-L1 * i1-(L-L1) * i2-sigma P bureau, # imgabs0 is combined with the two leakage point pressure equations, L1 is solved, and the position of the pipeline where the leakage point is located is judged according to the position of the pipeline where any one of the two pressure sensors is located. The leakage point identification method is simple and easy to operate, the position of the leakage point can be found by measuring a small amount of data and a simple algorithm, the working efficiency is greatly improved, the engineering cost is greatly saved, and the application range is wide.

Description

Technical Field

[0001] The invention relates to the technical field of water supply pipe networks, and in particular to a method for identifying leakage points in a water supply pressure pipe. Background Art

[0002] With the acceleration of urbanization and the continuous growth of population, the problem of water shortage has become increasingly prominent. As an important part of urban infrastructure, the operation status of the water supply network directly affects the effective use of water resources and the normal operation of the city. However, due to the influence of various factors such as pipeline aging, construction quality, geological conditions, etc., water supply network leakage problems occur from time to time, which not only causes waste of water resources, but also increases water supply costs, and may even have adverse effects on the environment and residents' lives. Therefore, water supply network leak detection technology came into being and became an important means to ensure water supply safety and improve water resource utilization efficiency.

[0003] The development of water supply network leak detection technology has gone through a process from simple to complex, from manual to intelligent. The existing leak detection methods mainly include:

[0004] (1) Listening method: by listening carefully along the pipeline, paying attention to whether there is water flow, dripping or other abnormal sounds, the leak point can be located. This method is simple, direct and low-cost, but it is only applicable when the leak is loud and the pipeline is shallow. It is not effective for deeply buried pipelines or environments with large noise interference.

[0005] (2) Observation method: observe environmental factors such as soil and vegetation around the pipeline, as well as signs of rust and damage on the pipeline to determine the leak point. This method is intuitive and easy to use, and does not require special equipment. However, it is only applicable when the leak point is obvious and easy to observe. It is difficult to find a leak point that is hidden.

[0006] (3) Regional environmental investigation method: Based on the water supply network map and the information provided by relevant personnel, a detailed investigation of the water supply pipeline is conducted, including the pipeline connection, distribution, material and surrounding medium conditions, and the leakage point is determined by observing the road conditions and the phenomenon of snow melting first in winter. This method takes into account multiple factors and improves the accuracy of leakage point identification, but the workload is large and time-consuming.

[0007] (4) Regional leakage noise automatic monitoring method: Use the regional leakage survey system to conduct centralized inspection of the water supply network in a certain community or a certain area, and automatically record and analyze the noise conditions of the pipeline through the preset probe to determine the leakage point. This method is suitable for leakage detection in large areas and has a high degree of automation, but the equipment cost is high and requires professional maintenance.

[0008] (5) The zone metering leak detection method measures the flow and pressure in the pipeline to determine whether there is a leak, which is the so-called minimum flow method. The pipe network is divided into several areas, and the flow and pressure are monitored separately to determine the leaking area. This method is applicable to water supply systems with large urban scale and complex pipe network structures. It can quickly narrow the scope of leak detection, but it requires a long period of monitoring data and high data processing capabilities.

[0009] (6) High-tech detection methods use some high-tech technologies to detect leaks, such as satellite remote sensing technology, which uses satellite images and special algorithms to analyze groundwater leakage characteristics. This method can cover a large area, but the equipment cost and technical requirements are extremely high.

[0010] In summary, existing detection methods are either simple but have low accuracy, low efficiency and limited scope of application, or have high accuracy but high equipment cost, complex operation, require professional personnel to operate, and the data processing is also relatively complex. Summary of the invention

[0011] The technical problem to be solved by the present invention is to provide a simple, efficient, accurate and low-cost method for identifying leakage points in a water supply pressure pipeline.

[0012] In order to achieve the above object, the technical solution adopted by the present invention is:

[0013] A method for identifying a leak in a water supply pressure pipeline comprises the following steps:

[0014] S1. Install multiple pressure sensors and flow meters on the pipeline to monitor the pipeline pressure and pipeline flow rate in real time and obtain basic pipeline information, including pipeline length, pipeline location of the pressure sensors and flow meters on the pipeline, pipeline loss along the pipeline, and the number and model of elbows on the pipeline;

[0015] S2. Calculate the pressure difference between the two pressure sensors according to the pressure values ​​measured by the pressure sensors;

[0016] S3, judging whether there is a leak in the pipeline. If the pressure difference between the two pressure sensors is equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is no leak in the pipeline between the two pressure sensors, and the process goes to step S2; if the pressure difference between the two pressure sensors is not equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is a leak in the pipeline between the two pressure sensors, and the process goes to step S4. The calculation equation of the theoretical pressure difference of the pipeline between the two pressure sensors is as follows:

[0017] ΔP 理论 =L×i+ΣP 局

[0018] Where ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i is the loss per unit length of the pipeline between the two pressure sensors, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors;

[0019] S4. Establish an equation to calculate the pipeline location of the leak, including:

[0020] S4.1. Establish the following leak point pressure equation:

[0021] ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局

[0022] Where ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor at the rear end of the two pressure sensors, L is the length of the pipeline between the two pressure sensors, L1 is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, i1 is the pipeline unit length loss (hydraulic gradient) between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, i2 is the pipeline unit length loss between the water outlet end of the leak and the pressure sensor at the rear end of the two pressure sensors, ΣP 局 The sum of the local losses of the pipeline between the two pressure sensors; S4.2, the leak point is equivalent to a right-angle elbow, and the right-angle elbow pressure loss formula is used to establish the following leak point pressure equation:

[0023]

[0024] Where ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors, ε is the loss coefficient, V 前 is the fluid flow rate in the pipeline where the pressure sensor located at the front end of the two pressure sensors is located, and g is the gravitational acceleration;

[0025] S4.3, combining the leak point pressure equations of step S4.1 and step S4.2, solving L1, and determining the pipeline position of the leak point according to the pipeline position of any one of the two pressure sensors.

[0026] Preferably, the following equation is established to solve the loss coefficient:

[0027]

[0028] Where ε is the loss coefficient, V 前 is the fluid flow rate in the pipeline where the pressure sensor located at the front end of the two pressure sensors is located (which can be obtained according to the flow meter located there), d is the pipeline diameter, V 后 is the fluid flow rate in the pipe where the pressure sensor at the rear end of the two pressure sensors is located (can be obtained according to the flow meter located there). According to the Water Supply and Drainage Design Manual, the value range of ε is [0.2,1.5]. Considering the linear quantization of the ε value and reducing the influence of pressure reduction on ε, the loss coefficient equation as mentioned above is established to improve the accuracy of the result.

[0029] Preferably, the pressure loss of each elbow is calculated using the Young-Stebbins formula, and the sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows in the pipeline between the two pressure sensors.

[0030] In some implementations, the equation for the sum of the local losses of the pipeline is:

[0031] ΣP 局 =aP 30°弯 +bP 40°弯 +cP 45°弯 +dP 50°弯 +eP 60°弯 +fP 70°弯 +gP 80°弯 +hP 90°弯

[0032]

[0033] Among them, ΣP 局 is the sum of local losses in the pipeline; a is the number of 30° elbows; b is the number of 40° elbows; c is the number of 45° elbows; d is the number of 50° elbows; e is the number of 60° elbows; f is the number of 70° elbows; g is the number of 80° elbows; h is the number of 90° elbows; ΔP 弯 is the pressure loss of the elbow; k is the empirical coefficient; V 弯 is the fluid velocity; g is the gravitational acceleration; P 30°弯 , P 40°弯 , P 45°弯 , P 50°弯 , P 60°弯 , P 70°弯 , P 80°弯 , P 90°弯 Refer to the calculation formula of ΔP 弯 The calculation formula is:30°弯 The k value is 0.20, P 40°弯 The k value is 0.30, P 45°弯 The k value is 0.35, P 50°弯 The k value is 0.40, P 60°弯 The k value is 0.55, P 70°弯 The k value is 0.70, P 80°弯 The k value is 0.90, P 90°弯 The value of k is 1.1.

[0034] Furthermore, the sum of the local losses of the pipeline also includes the local losses of the valves on the pipeline, that is, the sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows and all valves in the pipeline between the two pressure sensors. The pressure loss calculation formula of the valve refers to the elbow, the difference is that the value of k is different, and the specific value refers to the "Water Supply and Drainage Design Manual". When the valve is fully open, the value of k is 0. If there are non-energy-saving valves from decades ago, their values ​​are calculated with reference to the values ​​of non-energy-saving valves in the "Water Supply and Drainage Design Manual".

[0035] Preferably, the pressure sensor is corrected by using potential energy difference. In actual engineering, the pipeline is laid with bridge pipes, buried pipes, etc., which will cause a large potential energy difference, resulting in errors in the pressure sensor readings, which can reach 10% to 15% of the overall pressure difference. Therefore, the elevation should be corrected. Due to the different geographical locations of various project projects, different elevation systems are adopted. In this application, a unified elevation is used for correction, Wusong = Huanghai + 1.924m. In addition, this application also tests the elevation of the pressure sensor position used. In order to make the calculation accurate, the pressure at each point is corrected by the potential energy difference, that is, when installing the pressure sensor, without considering the loss along the way and the local loss, the pressure difference between the two adjacent pressure sensors (hereinafter referred to as the first pressure sensor and the second pressure sensor) is equal to the potential energy difference between the two, that is, P1-P2 = ρgH, where P1 is the pressure value of the first pressure sensor, P2 is the pressure value of the second pressure sensor, ρ is the fluid density, g is the acceleration of gravity, and H is the height difference between the horizontal plane where the second pressure sensor is located and the horizontal plane where the first pressure sensor is located.

[0036] Preferably, when the pipeline has more than two pressure sensors, the two pressure sensors are two adjacent pressure sensors.

[0037] In some implementations, step S2 includes calculating the pressure difference between any two adjacent pressure sensors on the pipeline.

[0038] Preferably, the pipeline loss along the way refers to the "Water Supply and Drainage Design Manual".

[0039] Preferably, the pipeline loss per unit length is obtained according to fluid mechanics and the calculation formula for the head loss per unit length of the pipeline in the "Outdoor Water Supply Design Code".

[0040] Furthermore, the pipeline loss equation per unit length is as follows:

[0041] (1) For old steel pipes and old cast iron pipes

[0042] When v<1.2m / s,

[0043]

[0044] When v ≥ 1.2 m / s,

[0045]

[0046] Where i is the head loss per meter of pipe, d j is the calculated inner diameter of the pipeline, v is the average flow velocity in the pipeline;

[0047] (2) For concrete pipes, reinforced concrete pipes and other pipes

[0048]

[0049] Where v is the average flow velocity in the pipe, R is the hydraulic radius, C is the velocity coefficient, Where n is the roughness coefficient, which is generally taken as 0.013-0.014. In specific calculations, the roughness coefficient should be determined based on the smoothness of the inner wall of the pipe.

[0050] Preferably, the water supply pressure pipeline leak identification system further comprises calculating the pipeline flow rate at the front end or rear end of the two pressure sensors. When calculating the pipeline flow rate at the front end of the two pressure sensors, the following equations are solved simultaneously:

[0051] ΔP 漏 =P 前 '-P 后 -L1×i1-(L-L1)×i2-(L'-L)×i3-ΣP 局 '

[0052]

[0053] ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局

[0054] When calculating the pipeline flow rate at the rear end of the two pressure sensors, the following equations are solved simultaneously:

[0055]

[0056] ΔP 漏 =P 前 -P 后 '-L1×i1-(L-L1)×i2-(L'-L)×i3-ΣP 局 '

[0057] ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局

[0058] Where ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors;

[0059] P 前 ' is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor located at the rear end of the two pressure sensors, P 后 ' is the pressure value measured by the pressure sensor located at the rear end of the two pressure sensors;

[0060] L1 is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, L is the length of the pipeline between the two pressure sensors, and L' is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors or the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors;

[0061] i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, i2 is the loss per unit length of the pipeline between the water outlet end of the leak point and the pressure sensor at the rear end of the two pressure sensors, i3 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the front end of the two pressure sensors (in this case, i3 is generally equal to i1) or the loss per unit length of the pipeline between the pressure sensor at the rear end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors (in this case, i3 is generally equal to i2);

[0062] ΣP 局' is the sum of the local losses of the pipeline between the pressure sensor located at the front end of the two pressure sensors and the pressure sensor located at the rear end of the two pressure sensors, or the sum of the local losses of the pipeline between the pressure sensor located at the front end of the two pressure sensors and the pressure sensor located at the rear end of the two pressure sensors,

[0063] V 前 is the fluid flow rate in the pipeline where the pressure sensor at the front end of the two pressure sensors is located, d is the pipeline diameter, V 后 V is the fluid flow rate in the pipeline where the pressure sensor at the rear end of the two pressure sensors is located, 前 ' is the fluid flow rate in the pipeline where the pressure sensors located at the front ends of the two pressure sensors are located, V 后 ' is the fluid flow rate in the pipeline where the pressure sensor located at the rear end of the two pressure sensors is located, and g is the gravitational acceleration.

[0064] Due to the large differences in the actual situation of the geographic information platform of the pipeline network in various regions across the country, the investment and maintenance costs of the flow meter are relatively large, while the investment and maintenance costs of the pressure transmitter (i.e., the pressure sensor) are relatively small, and the back-end flow data may be incomplete. Therefore, as long as the three pressure transmitters are combined to obtain the above equations, the flow velocity at the front end or the back end of the two pressure sensors can be obtained, and the flow rate can be further converted according to the inner diameter of the pipeline. Therefore, the method of the present invention has a large space for expanding application on the big data platform of the geographic information of the pipeline network.

[0065] The present invention also provides a water supply pressure pipeline leak identification system, which includes a pipeline, a control system, and a plurality of pressure sensors and flow meters installed on the pipeline and connected to the control system. The control system calculates the pressure difference between two pressure sensors in real time according to the pressure values ​​measured by the pressure sensors and determines whether there is a leak in the pipeline. When the pressure difference between the two pressure sensors is equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is no leak in the pipeline between the two pressure sensors; when the pressure difference between the two pressure sensors is not equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is a leak in the pipeline between the two pressure sensors, and the control system gives an alarm and calculates the position of the leak according to the equation, which is:

[0066]

[0067] Wherein, L1 is the length of the pipe between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, ΔP 实际 is the pressure difference between the two pressure sensors, ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors, V前 is the fluid flow rate in the pipe where the pressure sensor at the front is located, g is the acceleration due to gravity, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor at the rear end of the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, and i2 is the loss per unit length of the pipeline between the water outlet end of the leak and the pressure sensor at the rear end of the two pressure sensors;

[0068] The calculation equation for the theoretical pressure difference of the pipeline between the two pressure sensors is as follows:

[0069] ΔP 理论 =L×i+ΣP 局

[0070] Where ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i is the loss per unit length of the pipeline between the two pressure sensors, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors.

[0071] Preferably, the pressure loss of each elbow is calculated using the Young-Stebbins formula, and the sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows in the pipeline between the two pressure sensors, as described above and will not be repeated here.

[0072] Preferably, the pressure sensor is corrected by using the potential energy difference, as described above in detail, which will not be described in detail here.

[0073] Preferably, the two pressure sensors are two adjacent pressure sensors, the details of which are as described above and will not be repeated here.

[0074] Preferably, the loss per unit length along the pipeline is specifically as described above, which will not be repeated here.

[0075] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0076] The leak point identification method of the present invention is simple and easy to operate, and the leak point position can be found by measuring a small amount of data and a simple algorithm, which greatly improves work efficiency and greatly saves engineering costs, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] Figure 1 A plan view of a pipeline provided in Example 1;

[0078] Figure 2 A cross-sectional view of a pipeline provided in Example 1;

[0079] Among them, 1. pipeline; 11. first part; 12. second part; 13. third part; 14. fourth part; 15. fifth part; 16. sixth part; 2. first pressure sensor; 3. second pressure sensor; 4. leakage point; 5. third pressure sensor; 6. fourth pressure sensor;

[0080] X1, the length of the first part; X2, the length of the second part; X3, the length of the third part; X4, the length of the fourth part; X5, the length of the fifth part; X6, the length of the sixth part; a, the angle of the elbow. DETAILED DESCRIPTION

[0081] The present invention is further described below in conjunction with the examples. However, the present invention is not limited to the following examples. The implementation conditions used in the examples can be further adjusted according to the different requirements of specific use, and the implementation conditions not specified are conventional conditions in the industry. The technical features involved in each embodiment of the present invention can be combined with each other as long as they do not conflict with each other.

[0082] Example 1

[0083] A method for identifying a leak in a water supply pressure pipeline comprises the following steps:

[0084] S1. Install multiple pressure sensors and flow meters on the pipeline to monitor the pipeline pressure and flow rate in real time and obtain basic pipeline information. The basic pipeline information includes the pipeline length, the pipeline position of the pressure sensor and flow meter on the pipeline, the loss along the pipeline, and the number and model of elbows on the pipeline.

[0085] Usually, when it is necessary to determine whether a certain section of pipeline has a leak, it is only necessary to install two pressure sensors and flow meters at the beginning and end of the pipeline. However, when the pipeline is long, in addition to installing pressure sensors and flow meters at the beginning and end of the pipeline, a group of pressure sensors and flow meters can be selectively installed on the pipeline at intervals to more accurately determine the location of the leak. Figure 1 and Figure 2The pipeline 1 shown is used as an example. Along the flow direction of the fluid, the pipeline 1 includes a first part 11, a second part 12, a third part 13, a fourth part 14, a fifth part 15 and a sixth part 16 arranged in sequence, wherein a first pressure sensor 2 and a first flow meter (not shown in the figure) are installed at the liquid inlet end of the first part 11, which is connected to the second part 12 through an elbow (the angle a of the elbow is 60°), and the second part 12 is connected to the third part 13 through an elbow (the angle a of the elbow is 30°). Assuming that the leakage point 4 is located between the third part 13 and the fourth part 14, the fourth part 14 is connected to the fifth part 15 through an elbow (the angle a of the elbow is 45°), and the fifth part 15 is connected to the sixth part 16 through an elbow (the angle a of the elbow is 45°). The second pressure sensor 3 and a second flow meter (not shown in the figure) are installed at the end of the sixth part 16.

[0086] S2. Calculate the pressure difference between the two pressure sensors based on the pressure values ​​measured by the pressure sensors. When there are more than two pressure sensors on the pipeline, the pressure difference between two adjacent pressure sensors is usually calculated in sequence.

[0087] In this embodiment, the pressure difference between the pressure values ​​measured by the first pressure sensor 2 and the second pressure sensor 3 is calculated.

[0088] S3, judging whether there is a leak in the pipeline. If the pressure difference between the two pressure sensors is equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is no leak in the pipeline between the two pressure sensors, and the process goes to step S2;

[0089] If the pressure difference between the two pressure sensors is not equal to the theoretical pressure difference of the pipeline between the two pressure sensors, then there is a leak in the pipeline between the two pressure sensors, and step S4 is performed.

[0090] The theoretical pressure difference in the pipeline between two pressure sensors is calculated as follows:

[0091] ΔP 理论 =L×i+ΣP 局

[0092] Among them, ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors. In this embodiment, ΔP 理论 is the difference between the pressure values ​​measured by the first pressure sensor 2 and the second pressure sensor 3;

[0093] L is the length of the pipeline between the two pressure sensors. In this embodiment, L is the length of the pipeline 1 between the first pressure sensor 2 and the second pressure sensor 3. Since the leak point 4 is smaller than the pipeline 1, the length of the leak point 4 can be ignored, that is, the length of the pipeline 1 between the first pressure sensor 2 and the second pressure sensor 3 is equal to the total length of the first part 11 to the sixth part 16, L = X1 + X2 + X3 + X4 + X5 + X6;

[0094] i is the loss per unit length of the pipeline between the two pressure sensors. In this embodiment, i is the loss per unit length of the pipeline 1 between the first pressure sensor 2 and the second pressure sensor 3. Its value can be obtained by referring to the "Water Supply and Drainage Design Manual" or according to the calculation formula of the head loss per unit length of the pipeline in fluid mechanics and the "Outdoor Water Supply Design Code". The details are as above and will not be repeated here.

[0095] ΣP 局 The sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows in the pipeline between the two pressure sensors. According to the Water Supply and Drainage Design Manual, The values ​​of k for each elbow are shown in Table 1 below:

[0096] Table 1

[0097] α(°) 30 40 45 50 60 70 80 90 k 0.20 0.30 0.35 0.40 0.55 0.70 0.90 1.10

[0098] In this embodiment, ΣP 局 =P 30°弯 +P 60°弯 +P 45°弯× 2.

[0099] In some other implementations, the sum of the local losses of the pipeline between the two pressure sensors needs to be added with the local losses of the valve, as described above, which will not be repeated here.

[0100] S4. Establish an equation to calculate the pipeline location of the leak, including:

[0101] S4.1. Establish the following leak point pressure equation:

[0102] ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局

[0103] Among them, ΔP 漏 is the pressure difference at the leak point;

[0104] P 前is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors. In this embodiment, P 前 is the pressure value of the first pressure sensor 2;

[0105] P 后 is the pressure value measured by the pressure sensor located at the rear end of the two pressure sensors. In this embodiment, P 后 is the pressure value of the second pressure sensor 3;

[0106] L is the length of the pipeline between the two pressure sensors. In this embodiment, as described above, L=X1+X2+X3+X4+X5+X6;

[0107] L1 is the length of the pipe between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point. In this embodiment, L1=X1+X2+X3;

[0108] i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point. In this embodiment, i1 is the loss along the first part 11, the second part 12 and the third part 13. Its value is determined by referring to the "Water Supply and Drainage Design Manual";

[0109] i2 is the loss per unit length of the pipeline between the water outlet of the leak point and the pressure sensor located at the rear end of the two pressure sensors. In this embodiment, i2 is the loss along the fourth part 14, the fifth part 15 and the sixth part 16. Its value is determined by referring to the "Water Supply and Drainage Design Manual";

[0110] ΣP 局 The sum of the local losses of the pipeline between the two pressure sensors, as mentioned above, in this embodiment, ΣP 局 =P 30°弯 +P 60°弯 +P 45°弯× 2.

[0111] S4.2. Equivalent the leak point to a right-angle elbow, and using the right-angle elbow pressure loss formula, establish the following leak point pressure equation:

[0112]

[0113] Among them, ΔP 漏 is the pressure difference at the leak point;

[0114] ε is the loss coefficient. According to the Water Supply and Drainage Design Manual, the value range of ε is [0.2,1.5]. Considering the linear quantification of the ε value and the influence of reducing pressure on ε, the following loss coefficient equation is established to improve the accuracy of the results.

[0115]

[0116] ΔP 实际 =P 前 -P 后

[0117] V 前 is the fluid flow rate in the pipeline where the pressure sensor at the front end is located. In this embodiment, V 前 is the flow rate measured by the first flow meter;

[0118] g is the acceleration due to gravity.

[0119] S4.3, combine the leak point pressure equations of step S4.1 and step S4.2 to obtain:

[0120]

[0121] L1 can be obtained from the above equation, and then the pipeline position of the leak point can be determined according to the pipeline position of any one of the two pressure sensors.

[0122] The above method can find the leak point by measuring a small amount of data (measuring pressure and flow), without the need for additional expensive equipment. It only needs to install a pressure sensor and a flow meter on the pipeline, which greatly improves work efficiency and greatly saves engineering costs.

[0123] In addition, the actual differences in the geographic information platforms of pipeline networks in various regions across the country are relatively large. Since the investment and maintenance costs of flow meters are relatively large, and the investment and maintenance costs of pressure transmitters are relatively small, incomplete back-end or back-end flow data may occur. Therefore, when the back-end flow data is incomplete, just combine the third pressure transmitter to obtain the equation group:

[0124] ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局

[0125]

[0126] ΔP 漏 =P 前 -P 后 '-L1×i1-(L-L1)×i2-(L'-L)×i3-ΣP 局 '

[0127] Among them, P 后' is the measured value of the pressure sensor at the rear end of the second pressure sensor 3 (hereinafter referred to as the third pressure sensor 5), L' is the length of the pipeline between the third pressure sensor 5 and the first pressure sensor 2, i3 is the loss per unit length of the pipeline between the third pressure sensor 5 and the second pressure sensor 3, (in this case, i3 is generally equal to i2) ΣP 局 ' is the sum of the local losses of the pipeline between the first pressure sensor 2 and the third pressure sensor 5, V 后 ' is the flow rate of the pipeline at the rear end of the second sensor (ie the flow rate of the pipeline where the third pressure sensor 5 is located).

[0128] The above equations except for the leakage point L1, V 后 'Two unknowns, others such as i2, i3, ΣP 局 ,ΣP 局 'All V 后 The remaining numbers are also known numbers in the geographic information system. Therefore, the computer system can be used to solve the two-variable multi-time equation system to obtain L1 and V 后 '.

[0129] Of course, if the front-end flow is missing, it can also be calculated, as long as the first pressure sensor 2, the second pressure sensor 3 and the fourth pressure sensor 6 located at the front end of the first pressure sensor 2 are combined to obtain the equation group, the method is similar. Therefore, the present invention has a great space for expanding application on the pipe network geographic information big data platform.

[0130] In summary, the location of pipeline leakage in the present invention can be accurately calculated by pressure and flow values ​​and the original fixed parameters of the pipeline; in the pipeline network geographic information system, if a key data is missing (such as flow rate value), it can be accurately calculated by big data (such as pressure value); at the same time, the location of the leakage point can be calculated.

[0131] In addition, it should be noted that the water supply network system is usually monitored 24 hours a day, and the interval time for each data transmission is less than 50 seconds. Therefore, once the pipeline pressure changes, the location of the leak can be determined. The probability of a second leak or multiple leaks occurring within one minute is usually very small. Even if multiple leaks occur, multiple leaks can be identified by partitioning the pipeline, that is, installing pressure sensors and flow meters at certain intervals.

[0132] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for identifying leaks in a water supply pressure pipeline, characterized in that: It includes the following steps: S1. Install multiple pressure sensors and flow meters on the pipeline to monitor the pipeline pressure and pipeline flow rate in real time and obtain basic pipeline information, including pipeline length, pipeline location of the pressure sensors and flow meters on the pipeline, pipeline loss along the pipeline, and the number and model of elbows on the pipeline; S2. Calculate the pressure difference between the two pressure sensors according to the pressure values ​​measured by the pressure sensors; S3, judging whether there is a leak in the pipeline. If the pressure difference between the two pressure sensors is equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is no leak in the pipeline between the two pressure sensors, and the process goes to step S2; if the pressure difference between the two pressure sensors is not equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is a leak in the pipeline between the two pressure sensors, and the process goes to step S4. The calculation equation of the theoretical pressure difference of the pipeline between the two pressure sensors is as follows: ΔP 理论 =L×i+ΣP 局 Among them, ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i is the loss per unit length of the pipeline between the two pressure sensors, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors; S4. Establish an equation to calculate the pipeline location of the leak, including: S4.

1. Establish the following leak point pressure equation: ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局 Among them, ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor at the rear end of the two pressure sensors, L is the length of the pipeline between the two pressure sensors, L1 is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, i2 is the loss per unit length of the pipeline between the water outlet end of the leak and the pressure sensor at the rear end of the two pressure sensors, ΣP 局 The sum of the local losses of the pipeline between the two pressure sensors; S4.

2. Equivalent the leak point to a right-angle elbow, and using the right-angle elbow pressure loss formula, establish the following leak point pressure equation: Among them, ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors, ε is the loss coefficient, V 前 is the fluid flow rate in the pipeline where the pressure sensor located at the front end of the two pressure sensors is located, and g is the gravitational acceleration; S4.3, combining the leak point pressure equations of step S4.1 and step S4.2, solving L1, and determining the pipeline position of the leak point according to the pipeline position of any one of the two pressure sensors.

2. The method for identifying leakage points in a water supply pressure pipeline according to claim 1, characterized in that: The following equation is established to solve for the loss coefficient: Where ε is the loss coefficient, V 前 is the fluid flow rate in the pipeline where the pressure sensor at the front end of the two pressure sensors is located, d is the pipeline diameter, V 后 is the fluid flow rate in the pipeline where the pressure sensor located at the rear end of the two pressure sensors is located.

3. The method for identifying leakage points in a water supply pressure pipeline according to claim 1, characterized in that: The pressure loss of each elbow is calculated using the Young-Stebbins formula, and the sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows in the pipeline between the two pressure sensors.

4. The method for identifying leakage points in a water supply pressure pipeline according to claim 3, characterized in that: The equation for the sum of the local losses of the pipeline is: ΣP 局 =aP 30°弯 +bP 40°弯 +cP 45°弯 +dP 50°弯 +eP 60°弯 +fP 70°弯 +gP 80°弯 +hP 90°弯 Among them, ΣP 局 is the sum of local losses in the pipeline; a is the number of 30° elbows; b is the number of 40° elbows; c is the number of 45° elbows; d is the number of 50° elbows; e is the number of 60° elbows; f is the number of 70° elbows; g is the number of 80° elbows; h is the number of 90° elbows; ΔP 弯 is the pressure loss of the elbow; k is the empirical coefficient; V 弯 is the fluid velocity; g is the gravitational acceleration; P 30°弯 , P 40°弯 , P 45°弯 , P 50°弯 , P 60°弯 , P 70°弯 , P 80°弯 , P 90°弯 Refer to the calculation formula of ΔP 弯 The calculation formula is: 30°弯 The k value is 0.20, P 40°弯 The k value is 0.30, P 45°弯 The k value is 0.35, P 50°弯 The k value is 0.40, P 60°弯 The k value is 0.55, P 70°弯 The k value is 0.70, P 80°弯 The k value is 0.90, P 90°弯 The value of k is 1.

1.

5. The method for identifying leakage points in a water supply pressure pipeline according to claim 1, characterized in that: The pressure sensor is corrected using the potential energy difference.

6. The method for identifying leakage points in a water supply pressure pipeline according to claim 1, characterized in that: When the pipeline has more than two pressure sensors, the two pressure sensors are two adjacent pressure sensors.

7. The method for identifying leaks in a water supply pressure pipeline according to claim 1, characterized in that: The pipeline losses along the way refer to the "Water Supply and Drainage Design Manual".

8. The method for identifying leaks in a water supply pressure pipeline according to claim 1, characterized in that: The pipeline unit length loss is obtained according to the calculation formula of the pipeline unit length head loss in fluid mechanics and the "Outdoor Water Supply Design Code", which is as follows: (1) For old steel pipes and old cast iron pipes When v<1.2m / s, When v ≥ 1.2 m / s, Where i is the head loss per meter of pipe, d j is the calculated inner diameter of the pipeline, v is the average flow velocity in the pipeline; (2) For concrete pipes, reinforced concrete pipes and other pipes Where v is the average flow velocity in the pipe, R is the hydraulic radius, C is the velocity coefficient, Where n is the roughness coefficient, which is generally taken as 0.013-0.

014. In specific calculations, the roughness coefficient should be determined based on the smoothness of the inner wall of the pipe.

9. The method for identifying leaks in a water supply pressure pipeline according to any one of claims 1 to 8, characterized in that: The water supply pressure pipeline leak identification system further includes calculating the pipeline flow rate at the front end or rear end of the two pressure sensors. When calculating the pipeline flow rate at the front end of the two pressure sensors, the following equations are solved by combining: ΔP 漏 =P 前 '-P 后 -L1×i1-(L-L1)×i2-(L'-L)×i3-ΣP 局 ' ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局 When calculating the pipeline flow rate at the rear end of the two pressure sensors, the following equations are solved simultaneously: ΔP 漏 =P 前 -P 后 '-L1×i1-(L-L1)×i2-(L'-L)×i3-ΣP 局 ' ΔP 漏 =P 前 -P 后 -L1×i1-(L-L1)×i2-ΣP 局 Among them, ΔP 漏 is the leakage point pressure difference of the pipeline between the two pressure sensors; P 前 ' is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor located at the rear end of the two pressure sensors, P 后 ' is the pressure value measured by the pressure sensor located at the rear end of the two pressure sensors; L1 is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, L is the length of the pipeline between the two pressure sensors, and L' is the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors or the length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors; i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, i2 is the loss per unit length of the pipeline between the water outlet end of the leak point and the pressure sensor at the rear end of the two pressure sensors, and i3 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the pressure sensor at the front end of the two pressure sensors or the loss per unit length of the pipeline between the pressure sensor at the rear end of the two pressure sensors and the pressure sensor at the rear end of the two pressure sensors; ΣP 局 ' is the sum of the local losses of the pipeline between the pressure sensor located at the front end of the two pressure sensors and the pressure sensor located at the rear end of the two pressure sensors, or the sum of the local losses of the pipeline between the pressure sensor located at the front end of the two pressure sensors and the pressure sensor located at the rear end of the two pressure sensors, V 前 is the fluid flow rate in the pipeline where the pressure sensor at the front end of the two pressure sensors is located, d is the pipeline diameter, V 后 V is the fluid flow rate in the pipeline where the pressure sensor at the rear end of the two pressure sensors is located, 前 ' is the fluid flow rate in the pipeline where the pressure sensors located at the front ends of the two pressure sensors are located, V 后 ' is the fluid flow rate in the pipeline where the pressure sensor located at the rear end of the two pressure sensors is located, and g is the gravitational acceleration.

10. A water supply pressure pipeline leak identification system, characterized in that: It includes a pipeline, a control system, and a plurality of pressure sensors and flow meters installed on the pipeline and connected to the control system. The control system calculates the pressure difference between two pressure sensors in real time according to the pressure values ​​measured by the pressure sensors and determines whether there is a leak in the pipeline. When the pressure difference between the two pressure sensors is equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is no leak in the pipeline between the two pressure sensors; when the pressure difference between the two pressure sensors is not equal to the theoretical pressure difference of the pipeline between the two pressure sensors, there is a leak in the pipeline between the two pressure sensors, and the control system gives an alarm and calculates the position of the leak according to an equation, which is: Wherein, L1 is the length of the pipe between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak point, V 前 is the fluid flow rate in the pipeline where the pressure sensor at the front end of the two pressure sensors is located, d is the pipeline diameter, V 后 is the fluid flow rate in the pipeline where the pressure sensor at the rear end of the two pressure sensors is located, g is the gravitational acceleration, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors, P 前 is the pressure value measured by the pressure sensor located at the front end of the two pressure sensors, P 后 is the pressure value measured by the pressure sensor at the rear end of the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i1 is the loss per unit length of the pipeline between the pressure sensor at the front end of the two pressure sensors and the water inlet end of the leak, and i2 is the loss per unit length of the pipeline between the water outlet end of the leak and the pressure sensor at the rear end of the two pressure sensors; The calculation equation for the theoretical pressure difference of the pipeline between the two pressure sensors is as follows: ΔP 理论 =L×i+ΣP 局 Among them, ΔP 理论 is the theoretical pressure difference of the pipeline between the two pressure sensors, L is the length of the pipeline between the two pressure sensors, i is the loss along the pipeline between the two pressure sensors, ΣP 局 is the sum of the local losses of the pipeline between the two pressure sensors.

11. The water supply pressure pipeline leak identification system according to claim 10, characterized in that: The pressure loss of each elbow is calculated using the Young-Stebbins formula, and the sum of the local losses of the pipeline between the two pressure sensors is equal to the sum of the pressure losses of all elbows in the pipeline between the two pressure sensors; and / or, Correcting the pressure sensor using a potential energy difference; and / or, The pipeline loss per unit length is obtained based on fluid mechanics and the calculation formula for the head loss per unit length of the pipeline in the "Outdoor Water Supply Design Code" or refers to the "Water Supply and Drainage Design Manual".

12. The water supply pressure pipeline leak identification system according to claim 10, characterized in that: When the pipeline has more than two pressure sensors, the two pressure sensors are two adjacent pressure sensors.

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