https://mp.weixin.qq.com/s?__biz=Mzg3NzkxNTI1MA==&mid=2247484559&idx=1&sn=d1402e3f9fc75f7483a9dca3fc0174d4&chksm=cf1af992f86d7084c48ce7e4072fd6 be0555ec086c1065ef83398390c8bd19f2560daf594d7c&token=955052059&lang=zh_CN#rdIn the management of water supply construction, the most common problem is leakage. Prevention and control of water supply accidents, water loss, and water quality risks caused by leakage or damage of the pipeline network are important contents in the management of pipeline network construction and operation. Leakage problems involve a wide range and have many reasons. In-depth research is needed to propose appropriate optimization and adjustment countermeasures to improve leakage.
1. Analysis of existing problems in urban water supply network
The pipe network is aging, the pipe quality is not up to standard, the construction technology is outdated, and the leakage is serious
Due to various reasons, the pipe network in many cities has caused serious pipe bursts and various forms of open and hidden leaks. In the pipeline construction, the construction technology is outdated, or it is not carried out in accordance with the international construction norms, and the phenomenon of water leakage at the interface occurs from time to time. In addition, the quality of the pipes is low and seriously substandard. In some cities, the newly laid pipelines burst or severely ruptured within less than a year or even two or three months of normal use. Therefore, the frequency of pipe network leakage is high, resulting in serious loss of water resources, which not only brings huge costs and economic losses to enterprises, but also brings great pressure to water quality and pressure compliance.
Poor safety and reliability of water supply network
In order to cooperate with the construction of urban infrastructure, the construction of many pipeline networks ignores the scientific and rational progress of the preliminary design, construction, completion acceptance, etc., without demonstration, planning and layout based on experience, simple human decision-making, and connecting the pipeline networks in various periods , resulting in the overload operation of the local pipe network, resulting in an increase in pipe burst incidents.
Shortage of construction and maintenance funds
Due to the continuous expansion of the scale of infrastructure construction, the shortage of funds has become a common problem in various cities. Many water supply companies know that the pipe network is seriously aging and needs to be updated and upgraded, but they are short of funds, so they can only carry out simple repairs and maintenance, and pipe network ruptures will occur more frequently. In addition, the unreasonable allocation of funds for pipe network maintenance and renewal is often closely related to human decision-making, resulting in a shortage of funds in places where funds are needed, and one of the reasons is that funds are idle in areas that are relatively unnecessary.
2. Analysis of the causes of problems in the urban water supply network
Analysis of Internal Factors
Pipe quality is the most critical factor. The substandard quality of pipeline materials and supporting valves and other materials is the internal cause of leakage, and it is also a dilemma that urgently needs to be changed. According to relevant statistics, more than 80% of the leakage of my country's urban pipe network occurs in the poor quality of gray cast iron pipes and galvanized steel pipes.
Interface problem. In the maintenance and renovation of the pipe network in many cities, the old cement-asbestos interface is used to deal with interface problems, and new processes and technologies are not adopted. Furthermore, failure to strictly follow the requirements of construction specifications in actual construction is also the main reason for interface problems.
Fire hydrants, valves, and serious unqualified anti-corrosion inside and outside the pipeline are the direct causes of leakage. According to relevant statistics, in a city in the north, more than 30 new valves with a DN100 or more cannot be opened and closed within a year of use, and more than 10 valves have leaked and cannot be repaired. It has to be said that the quality problem of water-related products is the main reason for the leakage of the pipeline network.
Analysis of external factors
The foundation of the pipeline construction is not compacted and leveled, the earth backfill is not compacted in layers and does not conform to the backfill specification, the depth of the buried pipeline is not reached in accordance with the requirements of the construction specification, too many pipeline transfers exceed the allowable value, and the pier is piled Failure to follow the specifications or no pier at all, improper rubber ring at the interface or weak welding are the direct causes of leakage.
The phenomenon of freezing cracks caused by low temperature occurs from time to time. For southern cities, the temperature is relatively high, and there are not many phenomena of freezing and cracking pipes, water meters and valves, but it happens from time to time in northern cities. According to relevant data, in a city in the north, during the water supply pipe network renovation project, the temperature dropped sharply in 2010, and more than 100 water meters newly installed and put into use within a week were frozen and cracked and could not be used, and rework was carried out.
The impact of other constructions caused the pipe network to rupture. Due to the lack of supervision, the rupture of the water supply network caused by other engineering constructions is also a frequent phenomenon. According to relevant statistics, in 2013, a city carried out road renovations, resulting in as many as 300 ruptures of pipes of various calibers within three months.
Factors of pipe network operation
Due to the unstable water pressure, water hammer phenomenon occurred, which caused huge damage to the pipe network. For example, during the peak period of water consumption, the water consumption is large, and the water pressure is dynamic pressure, which is quickly released in a short period of time. However, the water pressure cannot be released during the time when the water is low, and the high pressure for a long time may easily cause the perforation of the pipeline or the fracture of the transverse surface, especially when the pressure changes sharply.
The leakage of valve wells and water meter wells is serious. In many cities in my country, the maintenance and repair of water supply facilities such as pipelines and well chambers are not in place, resulting in valves that cannot be opened and closed normally, exhaust valves that cannot be used normally, resulting in high pressure in pipelines, and users’ leakage information cannot be transmitted and resolved in time. cause of leakage.
3. Effective control measures for water supply network leakage
Optimizing the operation of the water supply network
Under the premise of the given user pressure requirements, choosing the appropriate pipe material, reducing the working pressure of the pipe network, and installing butterfly valves or water hammer eliminators to prevent water hammer is the best way to save energy, reduce leakage, and prolong the life of the pipe network. good way. In practice, it is necessary to analyze the user situation, carry out fine-grained management of users, and formulate a pipe network renovation plan suitable for users, in order to achieve this goal.
Implement partition metering management
Partition metering management is to artificially divide the overall water supply pipe network system into several smaller closed water supply blocks by installing flowmeters, water meters and other metering equipment on the pipe network nodes. Flow rate, pressure and other data are uploaded to the management platform. Based on these data, the water supply enterprise can intuitively understand the water supply volume of the water supply block, the operation status of the pipe network, and the water consumption habits of users through statistics and analysis, and take targeted measures for the pipe network. Management measures, so as to more effectively reduce the leakage rate of the pipeline network; and better manage the pressure of the entire system, and provide round-the-clock uninterrupted water supply services for the pipeline network system.
After the DMA is established, it is necessary to establish a long-term mechanism for statistical analysis of the feedback data of the pipeline network and to find problems, and implement measures depending on the specific situation, such as strengthening inspections and leak detection for DMA communities with high production-sales gap, and conducting geophysical verification for boundary pipeline networks The closeness of DMA, and even the establishment of a secondary DMA subsystem in the original DMA area, narrowing the detection range, etc.
Determine the pipeline network renewal and reconstruction plan
The leakage rate of the water supply pipe network is directly affected by the pipe material and pipe age. The old pipe network in the city should be continuously renovated, scientifically designed, strictly selected materials, carefully constructed, and priority should be given to the transformation of white iron, gray cast iron pipes, PVC pipes, Spheroidal cast iron pipes and other short-lived, easily corroded, and easily broken pipe networks control the leakage of water supply pipe networks from the source.
Machinery and intelligence, manual copying and remote transmission are always hot topics in the water industry at this stage. Despite the influence of NB-IoT and LoRa, the huge base of mechanical water meters in China makes this topic continue to have fresh vitality.