The valve model shall generally indicate the valve type, driving mode, connection form, structural characteristics, sealing surface material, valve body material, nominal pressure and other elements. The standardization of valve models provides convenience for the design, selection and sale of valves. Nowadays, there are more and more types and materials of valves, and the type designation of valves is more and more complicated. Although China has a unified standard for valve model, it is increasingly unable to meet the needs of valve industry development. For new valves that can't use standard number, each manufacturer can make models according to their own needs.