We have also talked a lot about the relevant knowledge of pressure vessel, so next we will explain the content of pressure vessel inspection, please see the following specific elaboration. Pressure Vessel External Inspection Also known as inspection in operation, the main contents of inspection are: whether there are abnormal phenomena such as cracks, deformation, leakage and local overheating on the outer surface of pressure vessel; whether safety accessories are complete, sensitive and reliable; whether fastening bolts are intact and tightened completely; whether there are abnormal phenomena such as subsidence, inclination of foundation and non-destructive damage of anti-corrosion layer. External inspection is not only the work of inspectors, but also the routine inspection items of operators. Discovering dangerous safety phenomena (such as cracks, deformations and serious leakage of compressed components) should be stopped and reported to the relevant personnel in time. Inspection of Pressure Vessel Internal and External Inspection of pressure vessels inside and outside must be done after parking and cleaning inside the vessels. The main contents of the inspection include not only the whole contents of the external inspection, but also the corrosion and wear phenomena of the internal and external surfaces. All welds, the transition zone of the head and other stress concentration areas are inspected with naked eyes and magnifying glasses for cracks. If necessary, the internal quality of the welds is inspected by ultrasonic or radiographic inspection; and the wall thickness is measured. If the measured wall thickness is less than the minimum wall thickness of the container, the strength check should be carried out again, and the pressure-lowering operation or repair measures should be put forward; if necessary, metallographic examination should be carried out for the vessels that may cause changes in metallographic structure of metal materials; and the main bolts of high-pressure and ultra-high-pressure vessels should be checked for cracks by magnetic powder or coloring, etc. Through internal and external inspection, we should analyze the causes of the defects detected and put forward some suggestions on how to deal with them. The repairs should be re-examined. The inspection cycle of pressure vessel inside and outside is every three years, but the inspection cycle of vessel with strong corrosive medium and highly toxic medium should be shortened. The inspection period should also be shortened for containers with serious defects found in operation, containers with poor welding quality and unknown corrosion resistance of materials to media. Cmprehensive Inspection of Pressure Vessels In addition to the above inspection items, pressure withstanding tests (generally water pressure tests) should also be carried out in the overall inspection of pressure vessels. Non-destructive spot check or all weld inspection shall be carried out on the main welds. However, for vessels with low pressure, non-flammable, non-toxic and non-corrosive media, if no defects are found, no non-destructive testing can be performed after certain experience has been obtained. The overall inspection cycle of containers is usually at least once every six years. For qualified containers filled with air and inert gases, the overall inspection cycle can be appropriately prolonged after obtaining experience and one or two internal and external inspections confirming that there is no corrosion. |
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