The water leak detector is a device used to detect whether there are water leakage problems in water source equipment such as pipes, water tanks, and pools. Its working principle is to judge whether there is a water leakage problem by detecting the environmental changes around the water source equipment. Next, the ATO will introduce you to the working principle of the water leak detector.
Structure of water leak detector
The water leak detector is mainly composed of three parts: sensor, controller, and alarm. The sensor is a part used to detect changes in the environment around the water source equipment, and it can sense changes in parameters such as temperature, humidity, and pressure around the water source equipment. The controller is used to process the data collected by the sensor and judge whether there is a water leakage problem according to the set threshold. The alarm is used to send an alarm signal to remind the user that there is a water leakage problem.
Working principle
The working principle of the water leak detector is based on the electrical conductivity of water. When the water source equipment leaks, the water will conduct electricity, thus changing the resistance value of the surrounding environment. A sensor senses this change in resistance value and transmits the data to the controller. The controller will judge whether there is a water leakage problem according to the set threshold and send out an alarm signal.
When the water supply pipeline leaks, the water sprayed out of the pipeline will rub against the leak, and collide with the surrounding medium, etc., and vibrations of different frequencies will occur. At the damaged part of the pipe, water leakage will form a sound wave and spread to both sides of the pipe in a sinusoidal manner, causing the pipe to vibrate. Spread to the ground through the surrounding media and pipelines. There are generally three types of leaks:
- Leakage friction sound: refers to the sound produced by the friction between the water sprayed out of the pipe and the leak, its frequency is usually 300 Hz ~ 2500Hz, and it propagates far along the pipe. The propagation interval is usually related to water pressure, pipe material, pipe diameter, interface, and the shape and size of the leak. Within the specified range, the sound of water leakage can be detected at exposed points such as gate fire hydrants.
- Water head impact sound: refers to the sound produced by the impact of the water sprayed out of the pipeline and the surrounding medium, and spreads to the ground through the soil in the form of a funnel. It can be detected on the ground by a leak detector or a listening rod, and its frequency is usually 100~1500 Hz.
- Medium friction sound: it refers to the sound produced by the water ejected from the pipeline driving the surrounding particles (such as soil particles, sand particles, etc.) to collide and rub against each other, and the frequency is low. When the listening rod is inserted near the underground leakage point, it can be heard. The friction sound of the medium was detected, which provided the basis for the final confirmation of the leak point.
In the beginning, the commonly used leak detection equipment was to capture these three sounds and accurately locate the leak point.
In addition to the principle based on the conductivity of water, smart water leak detectors can also use technologies such as sound waves and infrared rays to detect water leaks. For example, an acoustic water leak detector can tell if there is a water leak by detecting changes in the sound inside the water pipe. An infrared water leakage detector can judge whether there is a water leakage problem by detecting the change of infrared radiation around the water source equipment.
Sound detection
The principle of sound detection is that "leakage noise" of different frequencies occurs when water flows out of the pores of the pipeline. The frequency is determined by the water pressure, the size and shape of the leak point, the material of the pipeline and the terrain of the land. The use of ground microphones can be used to detect low-frequency leakage noise through the ground. But because this is also the frequency range for footsteps and traffic noise, it will take an experienced inspector to get satisfactory results. When there is noise in the detection leak, the leak may be located at the loudest point, but too much noise will increase the difficulty of direct and indirect sound detection, wind noise, traffic noise, etc. will cause problems in the detection work, so sound detection is suitable for at night.
Leak testing equipment
The leak detection equipment widely used at present is the underground pipeline leak detector. The leak stick is the original leak testing equipment, which consists of a stick body and an earpiece. Leak listening sticks are cheap and easy to use, and they can still play a big role in leak testing.
Water leak detector
The electronic water leak detector is a technical extension of the leak listening stick, which is composed of a probe, a host, and an earphone. The leak detection method of the leak detector is basically the same as that of the leak listening stick. The accessories and facilities of the pipelines in the tested area are checked one by one to see if there is any sound of water leakage. Listen to it step by step, and move slowly and carefully near the leaking point until the leaking point can be identified.
Correlator
When water leaks, it will emit noise and spread to the four directions. Because the acoustic properties of the transmission medium are different, it is often difficult to determine the location of the leak point. All kinds of strong disturbing noises in modern cities make this type of machine unable to work. The correlator judges the leak point according to the time difference when the sound of water leakage travels along the pipeline to the separate probe.
Conclusion
Underground pipelines are called underground "lifelines". These "lifelines" undertake the work of transporting energy and materials, and are the basis for the survival and development of enterprises. Therefore, it is of practical and far-reaching significance to carry out water supply pipeline leakage detection work to ensure the safe, stable, and healthy operation of water supply pipelines.
