introduction The safe operation of urban water supply network is the basic guarantee of urban construction and people's life. With the rapid socio-economic development of our country and the acceleration of urbanization, the construction scale of urban water supply network is increasing day by day. However, as a result of the loss of urban water supply network, the annual loss of water exceeding the actual water storage in Taihu Lake not only caused a lot of waste of high-quality water resources and disturbed normal production and living order, but also brought water quality risks and damage to underground public facilities Secondary hazards. Therefore, for water supply enterprises, prevention and control of water supply accidents due to leakage or damage of the pipe network, water loss and water quality risk are important contents in the operation and management of the network. During the "12th Five-Year Plan" period, the state attaches great importance to the construction of drainage pipelines and well controlled the leakage control of the pipelines, which is an important measure to realize urban water conservation and consumption reduction and improve the utilization efficiency of water resources. At present, the water supply network in our country has a serious leakage, with an average leakage rate of about 18% in pipe networks and a leakage rate of over 35% in some areas. In the urban water supply network leakage control, there is still a big gap compared with the international advanced level, resulting in unclear leakage and leakage monitoring and control of low efficiency issues, the urgent need to form a suitable network leakage in our country Comprehensive monitoring and control of common key technologies. Based on the water balance analysis and zoning management of network leakage evaluation, monitoring and control technology, starting from the status of our country's water supply network leakage and management technology level, the quantitative leakage of water balance analysis method, integrated leakage monitoring methods and the loss of comprehensive Control programs and many other technical content, formed based on the partition scheduling, regional control pressure, DMA pressure control leakage control and management of integrated technology, technology route shown in Figure 1. The technical application and demonstration provided technical support and solutions for the leakage control of water supply enterprises. The application of water supply network in Beijing achieved the effect of saving more than 30 million m3 of water annually. The future is expected to pass the promulgation and implementation of the industry standards and Beijing Demonstration role in the country to promote the application. 1 Pipeline Network Leakage Assessment and Monitoring Technology Based on Water Balance Analysis and Zoning Management As the pipe network is buried deep underground, it is very difficult to monitor the leakage point, which makes it difficult to repair the pipe damage point, renew the pipe network and control the pressure. Therefore, the monitoring and control of the pipe network leakage is the key to reduce the pipeline leakage A key and difficult point. Pipeline leakage assessment is the basis for effective monitoring and control of leakage, which can be conducted on different scales such as assessment of leakage water loss, assessment of pipeline leakage and assessment of pipeline leakage. Quantitative assessment of the amount of water leakage can reflect the overall health of the network as well as the management of enterprises and users of civilized level. The pipeline or pipe network leakage assessment, you can leak detection and pipe network maintenance programs to provide support for optimization. 1.1 water balance for our water supply network analysis At present, we use the leakage rate index to evaluate the leakage of water supply network. Although the calculation method of leakage rate and the evaluation standard are set, how to determine the influence degree of each component lacks the necessary analytical methods. The water balance sheet is a very good tool to identify the major components of a leak. The IWA standard water balance has been adopted by many countries' water supply departments and serves as the basic basis for leakage control of water distribution networks. However, due to the differences in the characteristics of pipe networks and measurement methods in China, it is impossible to copy IWC's water balance analysis methods and to put forward feasible methods that are suitable for our country. Therefore, on the basis of studying and absorbing IWC's water balance law, some contents of the standard water balance sheet are adjusted and refined (see Table 1). One is to abandon the unreadable "apparent leakage" Terms, and measurement errors alone as a major item, will steal the water, the user refused to check, the loss caused by the loss of water meter households and other households as "other losses"; second is the true loss is divided into clear leakage, Background leakage and water tank, pool leakage and overflow. The corrected water balance table is more in line with the actual situation of the operation and management of water supply enterprises in our country, and the concepts are clearer. It is not easy to bring misunderstandings and solve the problems that the water supply industry in our country didn \ 't understand the components of water leakage. When using the revised water balance table to quantify and analyze the amount of water in each component, the total amount of water supply and water consumption can be directly calculated according to the measurement data. The free water consumption can be obtained by collecting relevant data from the fire department. The other free water consumption Such as pipeline flushing, etc.) can also be obtained by measurement or estimation. The amount of water lost in the components of the water leakage loss, the amount of water loss measured, and the amount of other water losses need to be calculated and determined based on the results of the sample test. Such as measuring the amount of water loss is due to the differences between the measurement instruments at all levels as well as the measurement of water meter performance limitations caused by the water loss, the former is mainly household meter reading table after the total table error, the latter is mainly a large user meter Measuring loss. By carrying out the total score measurement loss test and the series test of different metering precision water meters, the measurement loss rate of these two factors can be obtained. Which can determine the entire network due to loss of measurement caused the loss of water. 1.2 based on the noise signal and DMA traffic data leakage monitoring network integrated monitoring technology One of the main reasons for the serious loss of pipe network in our country is the limited leakage monitoring and the low efficiency. Leakage detection based on the leak detector is an active leak detection method that can detect the leakage point, which has a direct effect on the location of the leakage point, but can not determine the size of the leakage. Many water supply units in our country are trying to pipe network management, which provides another measure for the monitoring and evaluation of pipe network leakage. DMA-based dropout monitoring can monitor traffic changes, directly reflect the loss, but can not locate the leakage point. Although theoretically by narrowing the detection area can eventually find the location of the missing point and the size of the amount of leakage, but this method is very large, often in the middle of the night, but also in a region frequently open and close some valves , Will lead to frequent changes in the water flow within the pipe, so that pipe scales off, bringing the risk of deterioration of water quality. DMA flow judgment and detection of leakage detector combined to form a comprehensive method of monitoring leakage, the technical route shown in Figure 2. That is, according to the DMA night minimum flow curve and the alarm signal of the leak detector, it can simultaneously obtain the size of the leak and the location information of the dropout, which can greatly improve the efficiency of the leak detection. 2 based on DMA leakage control and water pumping station regulation of pipe leakage and high efficiency control technology Leakage control can be from active leak detection, pipe network maintenance, pressure control, scientific management of four aspects. Proactively find the leakage point and promptly repair is the main loss control measures taken by most water supply units, but also a most basic loss control measures. Pressure control, relatively speaking, is the most effective loss control measures. Because the leak rate is directly related to the pressure leak, the pressure drop down immediately after the leak rate will be reduced. However, pressure control requires sub-regional management of the pipe network and installation of appropriate pressure control equipment at the regional water inlet. This investment is higher than the detection and repair of water leakage points but lower than the renovation of the pipe network. Therefore, the pressure control is one of the important technical means of pipeline leakage control. Under the premise of meeting the water demand of users, by reasonably reducing the pipeline pressure, the loss of water loss, the damage frequency and the natural growth rate of leakage can be effectively reduced, and the water saving , Saving energy, reducing consumption and extending the life of pipe network assets. At present, China has made some attempts in the area of ​​pipe network management and pressure control, but it still lacks sufficient scientific support. In the water supply network in Beijing 10 DMA pressure control test and found that the pressure control for leakage control has a certain effect, and different DMA response to pressure control effect is different. On average, every 1 km of pipe can save 0 water per 1 km of pressure drop Detailed Product
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Elevator Hall Call Panel / Car Operating Panel
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