I would like to ask the experts: are there suitable standard fittings for connecting pipes of different diameters?
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This post was last edited by leonardcy on 2017-2-3 at 13:52. For pipes like DN15 and DN25 that are connected on-site, are there any coupling types similar to slip couplings that can be fitted first onto the DN25 pipe and then the DN15 pipe connected? Set the working pressure at 2.5 MPa
This post was last edited by lovepds on 2017-2-3 at 14:00. For connecting pipes of different diameters, for straight pipe welding, concentric or eccentric reducer sleeves are used; the relevant standards include SH/T3408, GB/T12459, GB/T13401, and ASME B16.9. For smaller pipes, socket welding or threaded fittings are employed, along with reducer collars; the corresponding standards are SH/T3410, GB/T14383, ASME B16.10, etc. For the type shown in the diagram you provided, an eccentric pipe clamp can be used. Refer to the standards mentioned earlier; these are common types of pipe fittings. For this level of pressure, threaded sealing is not sufficient – socket welding is a better option. Use an eccentric double-socket pipe clamp, and select the appropriate grade based on the wall thickness of the pipe. If the pipe’s wall thickness is ≤ SCH80, use CL3000; for SCH160, use CL6000; and for XXS, use CL9000.
2.5mpa can only be used for welding reducer splices
LS said that using an eccentric pipe clamp would work too, right?
The reducer serves the same purpose as a pipe; both have flat ends rather than threaded ends. If tubes are used with pipe clamps, that will work. But if reducer fittings are used, socket weld fittings must be added at both ends, such as pipe clamps of the same diameter or elbows and the like. Using an eccentric tube clamp to handle this pressure is definitely no problem; even higher pressures have been handled in this way
For a pressure of 25 kilograms, welding of the large and small ends is still the preferred option