Leakage detection method of underground pipe leakage characteristics

Characteristics of underground pipe leakage

Pipe leakage is a phenomenon of water injection under pressure, which is ejected from the perforation or fracture to form a cavity with the fill soil, producing a certain frequency of sound, the frequency band of this sound is generally from several tens of Hz to several thousand Hz, after the soil medium on the high frequency sound part is greatly attenuated. Nevertheless, the sound of water leakage to the ground still has a certain sound pressure, its frequency is roughly between 100Hz and 2000Hz, the sound intensity of water leakage to the ground and the size of water pressure, leakage hole size, pipe type, pipe diameter thickness, soil properties and other factors. This characteristic of sound generated by water leakage provides a prerequisite for the discovery of water leakage and the identification of the leakage site.

Underground pipe leakage detection method

At present, China's underground water pipeline leak detection mainly uses passive maintenance method and sound listening method. Passive overhaul method is a method of sending people to overhaul only after the discovery of bright leaks. The sound listening method of leak detection is a method of using the sound generated by underground pipe leaks to estimate the leaky part of the pipe at ground level:

(1) Sometimes the sound is large, the range of the sound heard is too large, it is difficult to determine the correct location of the leak;

(2) Sometimes the sound of the leak is not necessarily the leak point, relying mainly on human experience;

(3) in the busy traffic, strong noise areas, sound listening method is difficult to work properly;

(4) some sound is too small, but also difficult to detect with the sound method. Although the sound method has been improved by many improvements, instrument performance and operator skills continue to improve, but there are still many cases of leakage detection can not be carried out, especially when the noise is too large, the pipeline is buried too deep, the inference of the location of the leak is very difficult, or impossible. Leak detection by correlation method is one of the methods based on overcoming the above disadvantages.

Buried pipeline leak detector

The PQWT-CL900 type pressure pipe leak detector produced by Hunan Puqi Geological Exploration Equipment Research Institute is a fully automatic leak detector with superior performance, which overcomes the problem of misjudgment due to changes in liquid or gas flow rate or pressure inside the pipe by a single leak detector. The specific pipeline leak detection method includes: arranging a group of samplers in a line array or matrix in the leak detection area of the pipeline; setting the working mode of the host in wireless mode, then instructing the samplers in the group to carry out data acquisition at the same time, and storing the sampling data of each sampler in blocks according to the sampler number, and determining the location of the leak by comparing and analyzing the simultaneous sampling data of each sampler.

Pressure pipeline leak detector

The main features of the product are.

1、Adopted foreign * digital signal processing chip and digital filter chip, controller integrated 16M cache, more responsive.

2, using 7-inch high-definition digital touch color LCD screen, resolution up to 800 by 480, full touch design, easy to operate.

3、9 probes use wireless module to send signal, no wiring, transmission distance up to 1000 meters. And 9 probes can measure at the same time, so that the measurement range is greatly increased, saving the user the time to find the water leakage.

4、Users can adjust the frequency range at will within the range of 70HZ-9000HZ.

5、In the range of 70HZ-9000HZ, it can display the distribution of the noise signal at each frequency in real time.

6, the sensor built-in preamplification circuit, the use of rubber ring seal and buffer, as well as the application of professional acoustic methods, making the ability to capture the noise higher than similar products.

7, using a large-capacity battery, can work continuously for more than ten hours.

8, super anti-interference circuit design, effective isolation of digital signals and analog signals, eliminating the noise generated by the digital circuit.