Flange connection is an important connection method in pipeline construction. Flange connection is to fix two pipes, pipe fittings or equipment on a flange plate, add flange pads between the two flanges, and fasten them together with bolts. Some pipe fittings and equipment come with flanges, which are also flange connections. Flanges are divided into threaded connection flanges and welding flanges.
Flange connection methods are generally divided into: flat welding, butt welding, socket welding, loose sleeve, thread.
1.Flat welding: only the outer layer is welded, and the inner layer does not need to be welded; it is generally used in medium and low-pressure pipelines, and the nominal pressure of the pipeline is less than 2.5MPa. There are three types of sealing surfaces for flat welding flanges, namely smooth, concave and convex, and tongue and groove. Among them, the smooth type is the most widely used, affordable and cost-effective.
2. Butt welding: The inner and outer layers of the flange must be welded. It is generally used in medium and high-pressure pipelines. The nominal pressure of the pipeline is between 0.25 and 2.5MPa. The sealing surface of the butt welding flange connection is concave and convex, and the installation is relatively complicated, so the labor cost, installation method and auxiliary material cost are relatively high.
3. Socket welding: generally used in pipes with nominal pressure less than or equal to 10.0MPa and nominal diameter less than or equal to 40mm.
4. Loose sleeves: Generally used in pipelines where the pressure is not high but the medium in them is relatively corrosive, so this type of flange has strong corrosion resistance and is mostly made of stainless steel. This kind of connection is mainly used for the connection of cast iron pipes, rubber-lined pipes, non-ferrous metal pipes and flange valves, etc. The connection between process equipment and flanges also uses flange connection.
The flange type has a flange on each end of the ball of the rubber joint. The fixed flange type is that the flange and the reinforced cord fabric in the rubber ball are vulcanized and bonded through the large flange sealing surface, and both ends cannot be rotated. When matching with pipelines, sometimes the direction of the bolt holes is misaligned and cannot be used. The loose flange type uses the reinforced cord fabric in the rubber ball to wrap the end steel wire ring and clamp it in the flange slot, which simultaneously plays the role of sealing and connection. The flanges on both sides can rotate.
To learn more, please visit the website:
www.baowi-steel.com