Up to now, the valve industry has been able to produce gate valves, globe valves, throttle valves, plug valves, ball valves, electric valves, diaphragm valves, check valves, valves, pressure reducing valves, traps, emergency shut-off valves, etc. 12 categories, 3000 Valve products of various models and more than 4000 specifications; high working pressure 600 MPa, large nominal diameter 5350 mm, high working temperature 1200 ℃, low working temperature -196 ℃. Applicable media are water, steam, oil, and highly corrosive media (such as concentrated nitric acid, medium concentration sulfuric acid, etc.). ), flammable media (such as benzene, ethylene, etc.), toxic media (such as hydrogen sulfide), explosive media, radioactive media face so many valve varieties, such complex working conditions, it is necessary to choose suitable installation in the pipeline system For the valve products, I think that we must first understand the characteristics of the valve; secondly, we must master the steps and basis for selecting the valve; in addition, the principle of valve selection should be followed. Valves generally have two characteristics: use characteristics and structural characteristics.
Use characteristics: It determines the main service performance and service scope of the valve. The use characteristics of the valve include: valve type (closed circuit valve, regulating valve, valve, etc.); product type (gate valve, globe valve, butterfly valve, ball valve, solenoid valve, etc.); valve main components (valve body, bonnet, valve stem, etc.) , Valve disc and sealing surface) material; valve transmission mode, etc.
Structural characteristics: determine some structural characteristics of valve installation, repair and maintenance methods, belonging to structural characteristics: the structural length and overall height of the valve , and the connection form with the pipeline (flange connection, threaded connection, clamp connection, external threaded connection, Welding end connection, etc.). ); the form of the sealing surface (inlay ring, threaded ring, surfacing, spray welding, valve body); valve stem structure (rotating rod, lifting rod), etc.