Understand the technical points of the sound listening method of the pipe leak detector

Listening to the sound method refers to the sound of water pipe leak detection instrument and equipment to identify water pipe leaks, according to the size of the leak and sound quality characteristics to determine the location of the leak method, in essence, should be called the sound vibration method. Listening to sound instruments include simple mechanical listening to sound rods and a variety of listening to sound leak detectors. Listen to the sound method is currently developing rapidly, is the most common and effective method used at home and abroad.

Pipeline leak detector listening to the sound method includes valve bolt listening method, ground listening method and drilling listening method. Valve bolt listening method can be used for water pipeline network leak census, detection of leakage area and range, as well as the predetermined location of the leak point; ground listening method can be used for water pipeline network leak census and precise location of the leak point; drilling listening method can be used for the precise location of water pipe leak abnormalities. When using the audible method for pipeline leak detection, the valve bolt audible method, ground audible method or drilling audible method should be selected according to the site conditions, and should have the following conditions: the pipeline water supply pressure should not be less than 0.15MPa, the environmental noise should not be greater than 30dB, the instrument used should be within the validity period specified in the national metrology verification.

1 valve bolt listening method

(1) valve bolt listening method can be used for water supply network leakage census, detecting the area and extent of leakage, and pre-location of leakage points, listening to the sound rod or sensor should be in direct contact with underground pipes or pipeline accessories.

(2) when using the valve bolt listening method, should first observe whether there is leakage in the exposed underground pipes or appurtenances, such as valves, hydrants, table rods, etc.. If there is a leak phenomenon should be repaired in a timely manner to remove interference, and then confirm the sound of listening for leaks to determine the leak pipe section, and then infer the leak point based on the strength and duration of the leak.

2 ground listening method

(1) the use of ground listening method, underground water supply pipeline burial depth should not be greater than 2m.

(2) ground listening method can be used to listen to the sound pole or pipe leak detector to detect when the sound pole or pickup should be close to the ground.

(3) in the pipeline leakage census, should be along the direction of the water supply pipeline, listen to the test points above the pipeline point by point, metal pipeline measurement points should not be greater than 2m, near the abnormal leakage should strengthen the density of measurement points, measurement point spacing should not be greater than 0.2m.

(4) When using the ground listening method to pinpoint leaks or leaks in non-metallic pipes with a diameter greater than 300mm, the pipe should be "S" shaped to facilitate listening, but the maximum distance from the centerline of the pipe should not exceed 1/2 of the pipe diameter.

3 drilling listening method

(1) The drilling and listening method can be used to accurately locate water pipe leaks, which should be found after the census of water pipe leaks.

(2) Before drilling, we should know information about other pipelines near the leak site, including the distribution and depth of electricity, telecommunications, natural gas, fiber optic cables and other underground facilities, so that we do not drill blindly and can use a pipe locator to detect and make sure there are no other obstacles before proceeding to avoid safety accidents.

(3) When using the borehole listening method of detection, the number of holes in each leak anomaly should not be less than two, and the spacing should not be greater than 0.5m.

(4) should use the borehole listening method to listen to the sound of the sound pole, listen to the sound of the sound pole should be in direct contact with the main body of the pipe to listen to the sound.

According to the detection conditions to choose the valve bolt listening method, ground listening method or borehole listening method, the detection method should be in line with the "urban water supply network leakage detection technical regulations" of the relevant provisions. The instruments and equipment used in the listening method should be maintained and calibrated in accordance with the regulations