Seeking advice on issues with connecting reducers
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Can eccentric (concentric) reducing nozzles be directly inserted into a flat flange for welding? Mainly, we need to know how long the straight sections on each side of the reducing nozzle are. If there isn’t enough straight section, a piece of straight pipe needs to be welded onto the reducer before the flange is welded on; this is quite troublesome. The standards for reducers are GB12459, and the specification I’m using is DN25. Thank you all! The standard only specifies the total length of the large and small ends, without indicating the length of the straight sections.
Eccentric (concentric) large and small ends generally should not be directly connected using butt-welded flanges. For reducers of size DN40 and below, eccentric short pipes are generally used as a substitute for reducers. The DN25 reducer has a length of 85 mm; it should be possible to weld it to an SW flange/SO flange, but not to two flanges.