Pipeline failure and maintenance-3

Release time:

2024-03-27

How to check and diagnose the pipeline?

(2) Coating defect detection although the above detection device can accurately detect the condition of the inner surface of the steel pipe, but the equipment is large, so the pipeline needs to stop running during the detection. Therefore, most people want to develop more simple testing equipment. Various methods of checking the external coating of pipeline on the ground surface without digging. The commonly used method is needle electrode method, that is, applying voltage on the electrode inserted into the ground at a certain interval, and measuring the potential difference between the two ends. The position of potential polarity reversal is the position of coating defect. This method has great reliability, and it can also detect small defects. However, it is easy to be affected by stray current and takes a long time to measure, which is the disadvantage of this method.

In addition, potential method and magnetic field method are commonly used in engineering. One terminal of the AC power supply is connected to one end of the tested steel pipe, and the other terminal is grounded. When the power is on, use the roller on the ground to detect the potential of the pipeline to the ground. The potential distortion will be produced in the pipeline defects. In this way, the defect position and corrosion degree of the pipeline can be determined.

The magnetic field intensity H is measured on the ground surface by magnetic field detector. The magnetic field is distorted at the defect, and the magnetic field intensity is reduced from H0 to h μ 0. In this way, the defect position and corrosion degree can be determined. In the vicinity of metal materials, the magnetic field distribution of this method is disordered, which will produce large errors. In general, potential method and magnetic field method can be used together.

What regulations should be observed when the fuel oil pipeline maintenance must be carried out in the open fire operation in the oil area?

Answer: for the maintenance of fuel oil pipeline, the following regulations shall be observed when open fire operation is carried out in the oil area:

1) Open fire operation is strictly prohibited within 50m from the oil tank farm. If open fire operation is necessary, hot work permit must be held.

2） The hot work maintenance section and the operation system shall be provided with reliable cutoff measures and plugged plates.

3) The pipeline and equipment for hot work maintenance shall be thoroughly flushed and ventilated, and the operation can only be carried out when there is no combustible gas.

4) There is no combustibles and combustibles around the hot work.

5) There should be a clear division of labor and strict organization during hot work. The person in charge of construction, hot work supervisor and fire fighting personnel must always be present, and relevant leaders should be present when necessary.

6) Although there is a hot work permit, the hot work shall be stopped immediately if any abnormality is found during the hot work.

7) When hot work is carried out in inflammable and explosive areas and pipelines and vessels of inflammable and explosive equipment, the gas inside shall be tested and analyzed.