Flange connection means that two pipes, fittings or equipment are first fixed on a flange, flange gaskets are added between the two flanges, and the two flanges are tightened by bolts. A detachable joint that is tightly integrated.
1. Flat welding: only welding the outer layer, no welding inner layer; generally used in medium and low pressure pipelines, the nominal pressure of the pipeline should be less than 0.25MPa. There are three kinds of sealing surfaces for flat welding flanges, namely, smooth, concave and convex, and tongue and groove. Among them, the most widely used is the smooth type, and the price is affordable and cost-effective.
2. Butt welding: The inner and outer layers of the flange are welded. They are generally used in medium and high pressure pipelines. The nominal pressure of the pipeline is between 0.25 and 2.5 MPa. The sealing surface of the butt welding flange connection is concave and convex, and the installation is complicated. Therefore, labor costs, installation methods, and auxiliary materials are all relatively high.
3 socket welding: generally used for nominal pressure less than or equal to 10.0MPa, nominal diameter less than or equal to 40mm in the pipeline.
4. loose sets: generally used for pressure is not high, but the medium is more corrosive in the pipeline, so this type of flange corrosion resistance, material mainly stainless steel.
This connection is mainly used for the connection of cast iron pipes, lining hoses, non-ferrous metal pipes and flange valves, and the connection of process equipment and flanges is also flanged.