Is patching allowed for thinning or leakage in pressure pipelines?
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As the title suggests, the provisions of the \"Regulations on Safety Inspection of Pressure Pipelines\" do not seem to explicitly prohibit strengthening the pipe walls or sealing leaks by using patching methods; does this mean such practices are permissible? This kind of situation is quite common in chemical plants. I’d like to ask everyone for advice, thank you.
It falls into the following categories: 1. Local corrosion in pressure pipelines leads to a reduction in wall thickness; reinforcement or plugging can be used to address this issue. 2. When large-scale corrosion of pressure pipelines leads to a reduction in wall thickness, it is necessary to conduct a safety assessment of those pipelines; simply reinforcing specific areas or sealing leaks is not sufficient. If the assessment results show that the pipelines do not meet the requirements for continued use, they must be scrapped – there is no room for compromise, as no one can afford the consequences of an accident.
1. There’s no need for that. 2. Mobile welding requires corresponding qualifications.
The main stressed components are not allowed to be patched; they can only be repaired by cutting out the damaged part or replaced
First, under what circumstances would one consider subsidizing pipelines? First, is it external wall corrosion or internal wall corrosion? If the outer wall is corroded, it can be repaired by welding repairs; if the inner wall is corroded, what diameter must the pipe have in order to allow welders to enter and make repairs inside? Furthermore, if welders can access the inside of the pipeline, repair can also be carried out by patch welding. Second, before the pipe wall is corroded, it can be approximated as a rectangular rotating membrane shell, with the radial third principal stress and bending stress being ignored. After thinning, whether the thinning is local or uniform (in fact, uniform thinning occurs very rarely; there are many defects within the material itself, so how can there be uniform corrosion-induced thinning?) Unless wear occurs, the assumption of a stress-free state in the original film no longer holds; the stress conditions at the corroded areas are complex and difficult to determine using simple rules. Therefore, simple patching is theoretically unsound.