Problems with flange connections for pipes and valves
Thread Content
The wall thickness of the flange on the pipeline side is DN400 SCH80s (12.7 mm) with a pressure class of 300, while the flange on the valve side is DN400 SCH80 (21.44 mm) also with a pressure class of 300. The combination of these two flange pressure classes results in an inner diameter difference of almost 9 mm. How should this situation be handled?
There are differences between the inner diameter of the pipe and that of the valve
It is most ideal to use a transition tube for connection.
It’s normal for the valve housing to be thicker than the pipe; valves are designed to provide throttling function anyway. Since the pressure ratings are the same in your case, there’s no other issue.
This post was last edited by longziyun on 2020-5-8 21:42. May I ask the original poster, what problems might arise with flange connections in this situation? It is quite normal for there to be differences in the inner diameter sizes of pipe flanges and valve flanges. With a nominal diameter as large as DN400, a slight difference in the inner diameter has no real impact at all. Please do not question the standards arbitrarily; it’s possible you’re just unaccustomed to them. :L
This is a normal error; just connect it and install it directly, and there will be no problem.