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The inherent causes of water meter rotation
From a theoretical analysis, the internal factor that causes the phenomenon of water table rotation is potential energy difference. Potential energy difference refers to the difference in the potential energy of objects at different time and place. There is a difference. Tap water is based on the principle that modern people can release desired clean water as soon as they open a tap at home. Its principle of action is that a water body with potential energy difference is unstable and in an unbalanced state. In order to achieve a natural equilibrium state, the potential energy of this difference will be automatically converted into kinetic energy, and the water will have a low potential energy from the direction of high potential energy. Flow, because the tap water exists in the pipeline, its flow direction is controlled by the pipeline, and it flows to the various outlet points along with the laying direction of the pipeline.
The mechanical water meter drives the impeller of its internal structure to rotate through the water flow, and drives the dial pointer to rotate through the transmission device to form the metering. This is the measurement principle of the mechanical water meter. From the above analysis, it can be seen that if the water meter is normal and there is no potential energy difference before and after the water meter, then the water meter will not rotate, and no measurement will be produced. The pressure fluctuations on the general municipal pipe network are very small and basically balanced. The potential energy difference between adjacent water bodies is very small and no water flow will occur. However, if there is an outflow point on the pipeline, there is a large potential energy difference in the pipeline, forming a flow of water and driving the meter to measure. Therefore, in the case of normal water use, metering will produce metering.
Three major factors causing poor potential energy
The major potential energy differences between adjacent water bodies in the pipeline are leakage, water hammer and airbag.
Leakage of water caused by the phenomenon of water meter rotation, from the working principle of the water meter can understand, it is the same as normal water. The solution is also very simple, it is to find the leak, repair can be.
Water Hammer Water Hammer refers to the fact that in a pressure pipeline, due to some external reasons (such as the sudden closure of the valve, sudden shutdown of the pump unit, etc.), the water flow rate changes abruptly, resulting in alternating changes in the sharp rise and fall in pressure. . From the description of the water hammer, it can be seen that the water hammer can cause the water pressure in the pipeline to rise and fall sharply. In this state, the water that is normally considered to be incompressible will become compressible. At this time, if there is a water meter near the pipeline, then the water in the pipeline behind the water meter will decrease in volume as the pressure of the pipeline increases, the pressure will drop and the volume will increase, forming a water flow before and after the water meter to push the water meter to measure, resulting in water meter Rotation phenomenon. This phenomenon is ubiquitous in the pipeline network. For example, in the two tables in the same corridor, when one household opens or closes the water, another water meter will generate a rotation; this phenomenon causes the rotation of the water meter to generally manifest itself as a positive water meter. Turning for a while, reversing for a while, the measurement positive and negative can basically be offset, and its frequency of occurrence and the impact of water hammer produced is also small. If the water hammer effect is large, a high frequency will affect the measurement, and it will also cause hidden dangers to the safety of the pipe network.
Airbag tap water production process is basically set up in the open, in the water will inevitably dissolve gas, while the maintenance of the pipe network will be mixed with gas, when the air into the pipe network can not be discharged in time, it will be in some pipe network The bulge or the end of the pipe gathers together to form the airbag, and the compressibility of the gas is large, which will exponentially increase the impact of the water hammer. If gas is stored in the water meter at this time, the water meter will spin, or if the gas volume is large and the pipe network pressure is extremely unstable, even if the gas does not exist behind the water meter, it will cause the water meter to rotate. In fact, this is also a kind of water hammer phenomenon. The solution is to discharge the gas that exists in each pipe section of the pipe network, which is mainly the highest point of the pipe section, the middle raised part and the dead water pipe end.
Solve the problem of water meter rotation
As can be seen from the above description, the main reasons for the rotation of the water meter are basically clear, and there are also targeted solutions. It is reasonable to say that the problem of the rotation of the water meter should be easily solved. However, from the point of view of the current problem of water meter rotation, the problem of water meter rotation is not only simple to handle, but also quite troublesome. There are mainly the following problems:
No one lived in a new home, and the gas in the home was easy to collect. This phenomenon is large in quantity and it takes time and effort to deal with it. After the problem is solved, the same problem will occur again after some time.
The new household pipeline is complex and there are many phenomena of water leakage and gas gathering. Nowadays, the user housing area is large, there are many sanitary wares, some sanitary wares are of poor quality, and they are prone to leaking water. In addition, the user population at home is generally not large. Some sanitary wares are not used for a long time, and airbags are easily collected to generate airbags. This phenomenon is also larger. .
The internal surface of the user's watch has been transformed to deteriorate the user's internal pipeline and the pipeline has not been completely reformed, resulting in more water leakage and gas gathering. When the household table is reformed, due to the aging of the pipeline in the user's home, it is easy to damage, and some of the redundant pipes cannot be dismantled in time during the reconstruction of the household table, resulting in pipeline gas collection. The water wares used in households to remodel users' homes are mostly old-fashioned, and they have been used for a long time, causing serious water leakage.
Secondary water supply. The current phenomenon of secondary water supply, which is caused by the secondary water supply, is relatively small. However, due to the large area of ​​rotation of the water meter due to this reason, the frequency of rotation is high and the amount of water produced is also relatively large. From the phenomenon of water table rotation caused by the current secondary water supply, the main reason for this phenomenon is that the size of the receiving municipal pipeline is small. The user uses the float valve to control the water level of the tank, and the water hammer is formed during the float valve control of the water level. In order to deal with this problem, users need to cooperate to adapt the tank water level control mode or increase the pipe diameter.
Municipal pipe network control point pressure is low. When the pipeline pressure is low, the water in the pipeline is in an extremely unstable state. When one of the users uses water, other users are affected. To solve the economic investment, the company needs to adjust the pipe network or increase the pressure pump station to increase the pressure of the pipe network.
Solution
Before and after the water meter close to the water meter installed check valve, since the water meter rotation is due to pressure fluctuations, caused by the compression of water, consider installing a check valve, check valve can play a role in preventing water backflow. In this way, when the pressure rises, the water is compressed and the water meter rotates positively; when the pressure decreases, the check valve closes automatically and the water meter does not rotate. When the pressure rises again, as long as the pressure is not higher than the pressure in the non-return valve, the water meter will not turn; the rotation of the water meter is mainly the water meter reciprocating many times before accumulating a large amount of water, install the check valve can reduce the rotation of the water meter The frequency can also solve the problem of water meter rotation caused by pressure fluctuations. However, due to the high frequency of domestic water use by residents and the small fluctuations in pipeline pressure, the check valves are required to have high sensitivity and high quality requirements.
Suggest
From the above analysis, it can be seen that except for the last point that the pressure on the municipal pipe network is low, the main factors that cause the water meter to rotate are not controlled by the water company. Therefore, the responsibility cannot be entirely borne by the water company. Therefore it is recommended that:
Clear boundaries and reasonably charge service fees. Proposing to draw a clear line on the phenomenon of self-rotation of water meters is a problem for the water company. The water company is duty-bound; if it is a user's problem, it needs a water company to assist in processing and it should reasonably charge a certain fee.
Strengthen the management of secondary water supply. For places where municipal pipelines are heavily loaded, such as adding secondary water users, the flow and installation methods should be controlled to reduce the impact of secondary water supply on the pipe network. At present, there have been four cases of all rotations of the water meter (including the buried surface along the line) caused by the secondary water supply float valve.
Where pressure on the municipal pipe network is low, pressure facilities should be provided.
In the district pipeline design, a certain number of exhaust valves shall be provided, and the arrangement of the exhaust valve shall meet the requirements of the national municipal pipeline exhaust valve design specifications.
When designing the user's table, a single-flow valve should be installed in front of the watch.
(Original title: Is your family's meter sneaking?)
After a large-scale form change action, there are always citizens who reflect that they feel that their water meters are turning faster. Are these meters really measurement inaccurate? Today, Xiao Bian took everyone to see what kind of phenomenon is the autobiographical phenomenon of the water meter.