Problems with connecting PE pipes to steel valves
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Hello everyone. Currently, PE pipes are connected to steel flanged valves, with the valves having an RF face (raised face). It is planned to use steel flanges and flange adapters to connect the PE pipes to these valves. I would like to ask whether such a connection is possible? Or should both sides adopt an FF (full-plane) structural format?
1. Flange joint: it’s sufficient as long as the center circle of the bolt holes, the bolt holes themselves, and the number of bolts match. 2. Regarding the sealing surface issue, the difference between RF and FF is not significant; the main difference is that RF has a protrusion, and with the same pre-tightening force, the sealing pressure is higher. 3. Use non-metallic soft gaskets and bolts of medium to low strength when assembling. Pay attention to the bolt preload; it should not be too high.
Generally, an FF sealing surface is chosen to prevent the flange from deforming when the bolts are tightened, which could otherwise cause damage to the side of the flange made of a weaker material.
This problem isn’t really that serious. As long as the flange sizes match. Place a rubber gasket in the middle for sealing. Then it’s fine to use steel bolts for tightening