Regarding threaded connection pipes
Thread Content
How are threaded pipe fittings and valves connected to the pipes? For example, in the case of PN40 LPG pipes, are the pipe threads processed on-site on the pipes themselves, or are standard threaded adapters used to weld onto the pipes before connecting them to the valves?
The diameter of this pipe can be chosen arbitrarily, as long as the pressure allows it and there is no leakage. For reference.
For threaded connections, considering the need for disassembly and reassembly, it is recommended to use a union joint. If disassembly is not required, the exposed portion can be welded after threaded connection to ensure sealing
In the case of a threaded safety valve, where the outlet has internal threads, how should it be connected? I’ve seen that the standards for union fittings specify internal threads; does that mean a short coupling with external threads is needed as well? This is way too complicated; I think safety valves also require regular inspection
Both internal and external threaded union fittings are specified in the GB/T26120 standard.