Solenoid Valve Selection Guide

Overview of a solenoid valve
Traced the history of the development of the solenoid valve, so far, at home and abroad solenoid valve principle divided into three categories (ie: direct-acting, step-by-step direct-acting, pilot), and from the valve structure and materials The different principle difference is divided into six branches subclass (direct-acting diaphragm structure, step-by-step diaphragm structure, pilot operated diaphragm structure, direct-acting piston structure, step-by-step piston structure, the pilot piston structure).
1, direct acting solenoid valve
Principle: power, the electromagnetic coil to generate an electromagnetic force off pieces brought from the valve seat, the valve opens; power, the electromagnetic force disappears, the spring force the closure of parts on the pressure in the valve seat, the valve closes.
Features: vacuum, negative pressure, zero pressure when working properly, but the general diameter of not more than 25mm.
2, step-by-step direct-acting solenoid valve
Principle: it is a direct-acting and pilot-operated combination of theory, when the inlet and outlet pressure ≤ 0.05Mpa, energized, the electromagnetic force directly to the pilot valve and the main valve closure member in turn lift up, the valve opens.pneumatic auto drain
When the inlet and outlet differential pressure> 0.05Mpa, energized, the electromagnetic force to open the pilot valve, the main valve chamber under increased pressure on the chamber pressure drops, pressure to the main valve is pushed upwards; power, the pilot valve and the main valve spring force or medium pressure to promote off pieces, moving down to the valve closed.
Features: zero pressure or vacuum, high pressure can also work reliably, but power is larger, requiring vertical installation.
3, the pilot solenoid valve
Principle: power, the electromagnetic force the pilot hole open, the upper chamber pressure decreased rapidly formed around the closure of parts on the lower high differential pressure, promote off pieces to move up, the valve opens; energized, the spring force pilot hole closed inlet pressure through the bypass hole rapidly into the low to high differential pressure in the upper chamber is formed around the closing valve member, to promote off pieces to move down, close the valve.
Features: high maximum fluid pressure range, but must meet the conditions of fluid pressure.flange solenoid valve