Views: 7 Author: pqwt Publish Time: 2022-09-30 Origin: PQWT
1. Preparation before leak detection
Factories, mines and enterprises, have their own water pipelines and water supply facilities, most of the units are equipped with a primary meter, secondary meter and tertiary meter, from the measurement point of view, it is easy to find the pipeline leakage, that is, the total amount of water is not right, which requires the use of leak detectors, underground pipeline detector for pipeline leak detection. Before the leak detector carries out the leak detection, the following preparatory work should be done.
(1) ask the relevant departments or relevant personnel, the introduction of pipeline leaks.
(2) Check the pipeline drawing information and ask the relevant personnel to understand the pipeline situation.
(3) Read the drawings and ask about the burial depth and water pressure of the pipeline.
(4) ask the relevant personnel about the place where the pipeline leakage is suspected.
(5) to unknown direction of the leaky pipeline to use the pipeline detector instrument to find out the plane location of the pipeline direction.
(6) prepare the instruments and tools for pipeline leak detection.
① Leak listening instrument; ② Steel fiber; ③ Tools for opening the manhole cover; ④ Pipeline meter; ⑤ Powerful flashlight, etc.
2. Determine the leakage area (the predetermined position for listening to leaks)
First from the end of the branch pipeline and the exposed part of the pipeline facilities for direct contact to listen to the leakage to find out the leakage clues of the leaking pipeline; contact with the pipeline to detect the leakage: contact the sensor to the exposed part of the pipeline: such as hydrant, valve, knuckle head, water meter, etc. If you hear an obvious nuisance sound or whistling sound, it is highly likely that a leak exists. In contact with the pipeline to listen to the leak, the sound of the water over the pipeline and the sound of the leakage of the pipeline should be strictly distinguished and printed in the brain, when you hear a shrill or whistling sound, pay attention to a careful comparison, the leak point in that direction.
3. Ground listening to the leak to determine the location of the leak
With direct listening to the leakage method, when the valve, section door, water meter at the pipeline to check and hear the sound of leakage, along the pipeline in the suspected leaky pipe section to listen to the ground to determine the location of the leaky plane.
1) Ground listening to the leak should have the following conditions.
(1) clear direction of the pipeline, pipe caliber and material.
(2) The burial depth of the pipeline.
(3) The water pressure in the pipeline should have a certain pressure.
(4) Obstacles and piles, etc.
2) Steps of listening to the leakage operation.
After the above situation is clearly understood, you can carry a good instrument to enter the site to work. According to the direction of the pipeline left, middle and right meandering curves forward, while listening to the sound of each point to identify and analyze whether it is the sound of water leakage, and whether the sound of the latter point and the former point have different and change.
The location of the black dot is the location where the leak detector pickups are placed. The sensor should be placed on the ground above the pipeline in a "Z" forward, in order to prevent the listening point from deviating too far from the pipeline and causing leakage, and the large pipeline should be listened to on both sides. Leak detection personnel need to understand the structure of the pipe network, in order to exclude the valve, tee and other pipe network accessories caused by the interference.
The pause time of the pickup is 5-10 seconds, which is not captured before the leak target, at this time, because no real leak sound is heard, each point of listening to the time is no longer useful.
(2) The key places along the pipeline where you hear the sound of water leakage, according to the volume, the difference in height to distinguish, and on the ground to mark out the leakage point.
(3) The second time the sound of abnormal locations and then carefully listen to the measurement, analysis, comparison, to find out the scope of the sound field of the leak, the location of the leak in the pipe (plane position) or deviation.
(4) on the ground above the pipe, hear "whirring" or "snorting" similar to the sound of waterfalls and only hear a little, you can be sure that this is the location of the leak.
If you hear two or more leaks at the same time, then after comparing, first repair the most certain leak, then listen to the pipe once with the direct contact method, and if there is still a leak sound, you need to review the location again.
4. Leak point correction and verification.
In the process of listening to the leak positioning, sometimes the location of the leak heard deviates from the pipeline, some of the leak sound blurred, to make the fixed point positioning can not make up their minds, I am afraid to cause misplanning or misfinding, laborious and time-consuming, reducing the accuracy of listening to the leak.
1, correction of deviation, verification methods.
(1) the plane position of the pipeline and the center of the leak sound to check, identify the size of the error, and then the leak will be delineated to the plane center of the pipeline in the location, detect the height of the water level.
(2) Playing ground brazing method: the diameter of 12m/mx1.5m steel brazing into the center of the leak sound, detecting the height of the water level.
(3) Place the pickup on the steel brazier and listen to the underground water leakage.
(4) With a three-pound Lang head, tap the ground and listen to its hollow sound.
5、Leakage point without obvious leakage sound
Most of the pipeline leaks with instruments can hear the sound of leaks and accurately find the location of the leak, but there are about 3-5% of the leak points, listening to check up the effort and effort to solve the problem is not too smooth. It is the case that
(1) the leak is submerged by water and the sound energy is absorbed by water.
(2) The pipe is buried too deep, the sound energy is absorbed by the soil and cannot be transmitted to the ground.
(3) The leak hole is too small
(4) Frozen layer is too thick
(5) The concrete floor is too thick, (more than 400MM)
(6) Water pressure is too low and the sound of the leak is weak
(7) there are extruded obstructions at the leak, to the point that the sound vibration is not good
(8) There is a downspout sound insulation above the pipe.
(9) There are buildings and piles on the ground and no space for listening to leakage activities.
(10) Leakage at the interface of large pipes (especially below the interface).
The above ten items are not the result of insufficient technical ability of the personnel listening to the leakage, nor the quality of the instrument, but the effort to solve them, purely because the situation is special, to be treated and viewed in a special way, as long as the specific treatment, the problem can always be solved. Hunan Puqi Geological Exploration Equipment Research Institute is a professional institution engaged in pipeline leak detection equipment and urban pipeline to reduce the loss of research. In the new generation of underground pressure pipeline leak detection equipment research and development field independent core leak detection technology has caused great concern in the industry, pipeline leak detection series of instruments have applied for a number of inventions, utility models, the formation of their own unique technical characteristics and advantages.