Issue of right-angle bends in pressure tapping pipes
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There is a project currently in progress where a large number of pressure transfer pipes with dimensions φ18X3 and φ22X3 are being used on site; the joints between these pipes are connected by socket welding. However, 90° elbows were not designed, and bends have to be created using pipe benders. Since the operating conditions are not high-pressure, it is now recommended that the design team switch to the more commonly used pipes with dimensions φ14X2 to facilitate construction. Could anyone with experience give some advice? 1. Is it possible to bend φ18X3 and φ22X3 pipes under normal circumstances? Some people say it will be very difficult to do so, as the wall thickness is high; the resulting shape won’t be as aesthetically pleasing as that of φ14X2 pipes. Is that true? 2. According to the relevant specifications, must 90° elbows be used for φ18X3 and φ22X3? Thank you.
All the pressure tapping pipes on site were bent by us, and they look fine as well. However, φ14X2 tubes are used. The pressure tap pipes have not used 18 or 22
No 90-degree elbows are needed; all bends have to be made using oxygen welding. If stainless steel is used for high-pressure pipelines, then cold bending is employed
We have previously bent 14*3 pipes, and the bends turned out very nice without affecting their appearance
This post was last edited by lotos1987 on 2017-5-22 00:58. Adding finished elbows means increasing the number of socket weld joints, which requires more welding tests and leads to unnecessary construction costs. At the same time, since the wall thickness of the instrumentation pipes is relatively small compared to that of the process pipelines, it is difficult to ensure welding quality, which can lead to welding defects and thus increases the risk associated with pressure-bearing pipelines. Therefore, the instrumentation piping should minimize the number of welds, using cold-formed pipes instead of elbows.
According to the relevant specifications, must 90° elbows be used for φ18X3 and φ22X3? There is no such mandatory requirement.
It’s too late; the use of socket-welded right-angle elbows has already been decided. Ugh, I’ve submitted the order twice already, and it’s really difficult to estimate the number of elbows needed.