Automatic valves and drive according to the classification

1, an automatic valve 'to rely on media (liquid, air, steam, etc.) and their ability to move the valve. If the safety valve, check valve, relief valve, steam trap, trap air solenoid valve and emergency shut-off valve, etc.
2, '' drive with manual valves, electrical, hydraulic or pneumatic valve to control. If the valve, the cut-off valve, throttle valve, butterfly valve, ball valve, such as Xuan Sefa