The Pipeline's Maintenance Method
一, The method of cleaning and removing the scale of the pipeline
The inner surface of the pipeline is in contact with various process media, which is prone to adhesion, siltation, deposition of various materials, and even blockage of the pipeline. At present, the commonly used descaling methods include mechanical cleaning, chemical cleaning and high-pressure water washing.
(1) Mechanical cleaning method
Mechanical cleaning (including manual cleaning with simple tools) can remove all dirt, especially chemical insoluble scales, such as sand, char and some silicates. It is not corrosive to the metal materials of the pipeline, but its efficiency It is much lower than the chemical cleaning method.
(2) Chemical cleaning method
The chemical cleaning method is a method of removing scale by the action of chemical solution with the dirt on the inner wall of the pipeline.
Chemical cleaning methods are usually divided into two types: circulation and immersion, and the circulation method is more commonly used. In order to increase the cleaning effect, it can be carried out in two directions in turn. When rinsing with clean water, operate in turn from two directions as well. In addition, in order to prevent corrosion during the cleaning process, when cleaning with a chemical cleaning agent that is corrosive to the pipeline, clean water should be used repeatedly after cleaning until the discharged water is neutral. This method has high efficiency and is especially suitable for cleaning piping systems. Because it can be operated in a closed system, it is widely used. However, chemical cleaning is highly professional and technical, and a little carelessness will not only fail to obtain the expected effect, but also may damage the pipeline or even cause an accident.
(3) High pressure water jet cleaning
The method of descaling with the impact of high-pressure water flow can be used to clean up the scale of the inner wall of the pipe and the outer space of the pipe bundle. Adding a sand-incorporated jet of fine quartz sand to the water stream can further improve the scouring force of the water stream. If the pipeline has dirt that becomes soft when exposed to oil, it can also be soaked in oil first, and then rinsed with high-pressure water. The high-pressure water jet flushing method has high efficiency and does not pollute the environment, so it is also widely used as the chemical cleaning method.
二, The repair method of pipe wall thickness reduction
After the pipeline has been in operation for a period of time, a common defect is the thinning of the local pipe wall. The local wall thickness reduction caused by corrosion depression and medium erosion can be treated with repair welding or partial pipe replacement depending on the severity of the plot. For pipes with reduced wall thickness, if the reduction exceeds the designed corrosion allowance, there will be problems due to insufficient strength. When the measured actual wall thickness is generally less than the allowable small wall thickness of the pipeline, the pipeline should be used for pressure reduction or scrapped.
三，The repair method of pipeline cracks
The cracks formed on the pipe wall of the pipeline are roughly divided into two types: surface cracks and penetrating cracks, and their repair methods are also different. Industrial video pipeline endoscopes play a very good auxiliary role in pipeline internal inspection.