Electric valve is through the motor drive valve stem, drive the valve core action, electric valve is divided into (shut off valve) and regulating valve. Close the valve is a two-bit operation that is fully open and fully close, the regulating valve is installed on the electric valve positioning device, through the closed loop adjustment to make the valve dynamic stability in a position. Function features of solenoid valve: external leakage, easy to control internal leakage, safe use; the system is simple, connected to the computer, low price; action express, small power, light appearance, limited adjustment accuracy, limited applicable media; various models and wide use