Valves class
There are self-driven valves and operated valves. self-driven valves( like safety valve, relief valve, steam trap, check valve ) are functioning by utilizing its mechanical design or the pressure, direction of its flow medium.operated valve( like gate valve, globe valve, ball valve, butterfly valve ) is fuctioning by actuator( manual, electric, hydraulic, pneumatic etc. ) or the pressure , flow direction of its medium. due to the differences of pressure, temperature, flow, and physical-chemical character of its medium , there are different requirements in designing and applying the pipeline system.therefore there are numerous types of valve.according to an unofficial statistics, there are more than four thousand types of valve with approximately forty thousand specifications in China. Obviously, valve is an important element in the social economy.
