Analysis of the use of buried pipeline anti-corrosion layer detection leak detector - Database & Sql Blog Articles

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Underground pipeline anti-corrosion layer leak detector

The detection principle involves sending a specific high-frequency modulated signal into the underground pipeline. This signal forms a loop with the earth at the point where the anti-corrosion layer is damaged, and it radiates to the surface. The strongest radiation occurs directly above the damage, allowing the location of the break in the anti-corrosion layer to be identified. The method used is the "body capacitance method," where the human body acts as the sensing element of the leak detector. When the detector approaches the leak point, it emits an audible alert. When directly over the leak, the reading is highest, enabling precise identification of the leak. However, what are the key precautions when using this type of buried pipeline anti-corrosion leak detector? Here’s a detailed guide from Beijing Jintai Keyi.

When using the underground pipeline anti-corrosion layer detection leak detector, the following points should be carefully observed:

1. While the probe receiver is working, it may sometimes detect false signals from the pipeline. These artifacts usually have the following characteristics, which can help distinguish them:

(1) The signal strength measured at the false location does not match the actual position of the pipeline.

(2) The positions determined by the peak method and zero-value method do not align.

(3) Changing the signal injection point of the transmitter or the grounding point of the ground wire will eliminate the artifact.

2. For depth measurement, the center of the pipeline is the reference. To find the top of the pipeline, subtract the radius of the pipe from the measured depth. For large-diameter pipelines, the dummy points may be wide, so corrections should be made by taking the center of the dummy point for accurate positioning and measurement.

3. There is a blind spot around the transmitter where the receiver might pick up signals from both the transmitter and the pipeline. If you need to detect within this area, move the transmitter slightly further away to avoid interference.

4. If the peak and zero calibration marks coincide, the positioning is considered accurate. If they don’t match, the positioning is inaccurate. The error mark appears on the same side of the pipeline, and the actual pipeline position is closer to the peak.

5. Whether the pipeline sounding is accurate largely depends on the accuracy of plane positioning. If there are other nearby pipelines, especially at branches or sides, their magnetic fields may overlap. The readings at these points reflect the combined effect of multiple pipelines, distorting the magnetic field compared to a single pipeline. Therefore, it's best to perform the sounding in the middle of a straight section of the pipeline, with the straight segment being longer than five times the depth of the pipeline.

6. The soil covering the pipeline must make good contact with it. Newly laid pipelines should be compacted after being covered with soil, ensuring full contact before conducting leak detection. Otherwise, the results may be unreliable.

7. When performing leak detection, the horizontal method should be used. The probe should walk directly above the pipeline, while the operator stays away from the pipeline to ensure the leak detector's detection line is perpendicular to the pipeline direction. When the maximum value and sound are detected, that location is the leak point.

8. Both test leads of the leak detector must maintain good contact with the user’s body. Avoid touching the shielding layer, and ensure the core wire and shielding layer do not come into contact, as this could cause the detector to malfunction.

9. The transmitter’s ground wire should preferably not cross other pipelines or be placed on top of another one. This could cause the transmitted signal to couple with other pipelines, leading to incorrect readings.

We welcome everyone to explore and learn more about this essential tool for pipeline maintenance and safety.