Valve is an important part of large complete sets of equipment. It is mainly used for cutting, throttling, pressure regulating and changing direction of process piping medium (materials, water, steam, air and oil, etc.). The quality of the valves directly affects the normal production, safe operation and environmental pollution of these devices, and plays a vital role. There are many kinds of valves, such as gate valves, globe valves, check valves, ball valves, safety valves, pressure reducing valves, steam traps, butterfly valves and special purpose valves. According to incomplete statistics and rough estimation, the investment of valves in a set of large sets of equipment accounts for about 5% of the total investment of the equipment.
Through the implementation of national standards, the introduction of technology, strengthen the testing and detection methods, and improve the reform of the old product design and technological level, the level of our valve products have greatly improved in the past 20 years, a large increase in the number of varieties and specifications, especially in hard seal butterfly valve, ball valve and plate increase gate valves and other types of products and the rapid (14 categories of nearly 2000 existing valve series, more than 12000 specifications). Large sets of foreign devices continue to expand the scale, promote the valve supporting level and to adapt to the domestic, have such a trend, but the supporting capacity and a larger gap between the developed countries, mainly in the special valve high parameters valves, control system and driving device etc..