Flanged valve

Flange connection valve, its installation and disassembly are more convenient, but flange connection than threaded connection valve bulkier, the corresponding price is high, so it is suitable for a variety of diameter and pressure pipe connection. When the temperature exceeds 350 degrees, because the bolts, gaskets and flanges become relaxed, but also significantly reduce the load of bolts, the stress of a large flange connection may leak.

Threaded valve

Threaded valves are mainly nominal conduits below 50mm. If the diameter size is too large, the installation and sealing of the connecting part is very difficult. Threaded connections are usually machined into conical or straight pipe threads at the inlet and outlet end of the valve so that it can be connected to the conical pipe threaded joint or pipe path. Because of the possibility of large leakage channels in this connection, sealant, sealing tape or packing can be used to plug these channels. If the body material is weldable, but the coefficient of expansion varies greatly, or the range of operating temperature variation is large, the threaded joint must be honey sealed. To facilitate installation and removal of threaded valves, fittings are available at appropriate locations in the piping system. Valves with nominal diameters up to 50mm may use a sleeve joint, threaded to join the two connecting parts together.

Welded valve

In the nominal diameter is larger, the use of conditions engraved, high temperature occasions, the valve body often adopts groove welding, at the same time, the welding joint has the original lattice requirements, must choose the technical excellent welder to complete the work. Welded valves with nominal diameters up to 50mm usually have welded sockets to hold the pipe at the flat end of the load. Because slot welding forms a gap between the socket and the pipe, the gap may be corroded by some media. At the same time, the vibration of the pipe will make the connection part fatigue, so the use of slot welding is limited to a certain extent. Welded connections are suitable for various pressures and temperatures, and are more reliable than flange connections when used under better conditions. However, the disassembly and reinstallation of welded valves are more difficult, so its use is usually limited to long-term reliable operation, or service conditions, high temperature occasions. Such as thermal power plants, nuclear power projects, ethylene projects on the pipeline.