Valve and pipe connection

There are three types of valves and pipes that are commonly used, namely threaded connections, flanged connections and welding. In addition, butterfly valves are also clip-on and lug-connected.
  (1) Threaded connection
  In small diameter valves, threaded connections are common and are much more economical than flanged connections. Threaded connections are commonly used with tapered pipe threads to ensure sealing performance at the valve and pipe connections. Pipe threaded connections are typically used for valves of DN50 and below, and are not suitable for high temperature valves.
  (2) Flange connection
  Flanged valves are easy to remove from the pipeline and are suitable for a wide range of temperatures from -273 to 815oC; since the flange connection is fixed by a number of bolts, the tightening torque required for a single bolt is smaller than the corresponding threaded connection. Therefore, it can be applied to valves of various pressures and sizes. When flanged, the flange faces are mostly smooth, as well as large flat and grooved flanges.
  (3) Welding
  The advantage of the welding intercepting valve is that the valve joint is not leaky, safe and reliable, and the installation cost is low. It is suitable for pipelines with various temperature and pressure; the disadvantage is that it is difficult to remove the anti-valve after welding, and it is not suitable for materials that are difficult to weld; Conditions with harsh conditions and high temperatures./p>