Whether the choice of the connection mode between the valve and the pipeline or equipment is correct and appropriate will directly affect the probability that the pipeline valve will run, run, drip and leak.
Common valve connections include: flange connection, clip connection, butt weld connection, threaded connection, ferrule connection, clamp connection, self-sealing connection, etc.
First, the flange connection:
The valve body has flanges at both ends, corresponding to the flange on the pipe, and is installed in the pipe through the bolt fixing flange. Flange connections are the most used form of connection in valves. The flange has a face (RF), a plane (FF), a convex and concave surface (MF), and the like. According to the shape of the joint surface, it can be divided into the following types:
1. Smooth type: It is used for valves with low pressure and is convenient to process.
2. Concave and convex type: high working pressure, can use medium and hard washers.
3. Gutter type: It can be used with gaskets with large plastic deformation. It is widely used in corrosive media and has good sealing effect.
4. Trapezoidal trough type: use oval metal ring as a gasket, used for valves with working pressure ≥ 64 kg / cm 2 , or high temperature valves.
5. Lens type: the gasket is a lens shape, made of metal. For high pressure valves with working pressure ≥100 kg/cm 2 or high temperature valves.
6. O-ring type: This is a newer form of flange connection, it developed with the appearance of various rubber O-rings, it is more reliable than the general flat washer in the sealing effect.
Second, the clip connection
The valve is installed in the middle of the two flanges. The valve body usually has a positioning hole to facilitate the installation and positioning, and the bolt and the two pipes are directly clamped together by bolts.
Welded connection
1. Butt welding connection: Both ends of the valve body are processed into butt welding groove according to the requirements of butt welding, corresponding to the welding groove of the pipe, and fixed on the pipe by welding.
2. Socket welding connection: Both ends of the valve body are processed according to the requirements of socket welding, and the pipe is connected by socket welding.
