Pressure Vessel Test

External inspection

Also known as inspection during operation, the main contents of the inspection include: whether there are any abnormal phenomena such as cracks, deformation, leakage, and local overheating on the outer surface of the pressure vessel; whether the safety accessories are complete, sensitive and reliable; whether the fastening bolts are intact and all tightened; Whether the foundation sinks, tilts, and the anti-corrosion layer is damaged. External inspection is not only the job of the inspector, but also the routine inspection item of the operator. Safety-endangering phenomena (such as cracks, deformation, serious leakage of pressure components, etc.) should be stopped and the relevant personnel should be reported in time.

Internal and external inspection Pressure vessel

The inspection of the inside and outside of the pressure vessel can only be carried out after parking and cleaning the inside of the vessel. The main content of the inspection includes all the contents of the external inspection, as well as the corrosion and abrasion of the inner and outer surfaces; use the naked eye and a magnifying glass to check all welds, head transition areas and other stress concentration parts for cracks, and use ultrasonic waves when necessary Or radiographic inspection to check the internal quality of the weld; measure the wall thickness. If the measured wall thickness is less than the minimum wall thickness of the vessel, the strength check should be carried out again, and pressure reduction or repair measures should be proposed; for vessels that may cause changes in the metallographic structure of metal materials, metallographic inspection should be carried out if necessary; The main bolts of ultra-high pressure vessels should be inspected for cracks using magnetic powder or coloring. Through internal and external inspections, analyze the causes of the defects detected and put forward treatment opinions. Re-inspection is required after repair. The inspection cycle for the inside and outside of the pressure vessel is once every three years, but the inspection cycle for the container for strongly corrosive and highly toxic media should be shortened. Vessels with serious defects found in operation and vessels with poor welding quality and unknown material’s corrosion resistance to the medium should also shorten the inspection period.

Comprehensive inspection

In addition to the above-mentioned inspection items, the pressure vessel comprehensive inspection must be subjected to a pressure test (generally a hydraulic test). Carry out non-destructive inspection spot inspection or all weld inspections on main welds. However, for vessels with very low pressure, non-flammable or non-toxic, non-corrosive media, if no defects are found, after obtaining certain experience, non-destructive inspection is not required. The overall inspection cycle of containers is generally carried out at least once every six years. For manufactured qualified containers containing air and inert gas, the overall inspection period can be appropriately extended after obtaining use experience and one or two internal and external inspections to confirm that there is no corrosion.