A: direct-acting solenoid valve
There are normally closed and normally open type two kinds. Normally closed when the power was off, when the electromagnetic force generated when the coil is energized, the moving core to overcome the spring force with static core pull directly on the valve, the medium was access; when coil power electromagnetic force disappears, an iron core under the action of the spring force of the reset, close the valve directly to the mouth, medium barrier. Simple structure, reliable action, at zero pressure and micro-vacuum work. Normally open just the opposite.
B: step by step direct-acting solenoid valve
The valve is used to open the valve and a valve connected to the second one to open the main valve and pilot valve step by step so that the electromagnetic force and the pressure directly on the main valve port. When the coil is energized, the electromagnetic force to produce dynamic and static core core pull, the pilot valve and pilot valve port open port located on the main valve port, and the moving core together with the main valve, then the main valve the pressure chamber through the pilot valve port unloading, the pressure difference and the electromagnetic force, while under the effect of the upward movement of the main valve, open the main valve media circulation. When the coil power electromagnetic force disappears, this time moving core in the role of weight and spring force to close the valve guide hole, the hole in the balance in the media at this time into the main valve on the chamber, so that the chamber pressure increases, this time in the spring and pressure shut down the main valve, the media stop. Reasonable structure, reliable operation, when the zero-pressure work reliably.
C:indirect pilot solenoid valve
This series solenoid valve spool by the pilot valve and main contact with the formation of channel combinations; normally closed when without power, was closed. When the coil is energized, magnetic force generated by the moving core and static core pull, the pilot valve port open, the flow of exports to the media, this time the main valve to reduce pressure on the chamber, the pressure is lower than the import side, the formation of pressure to overcome the spring the resistance along the upward movement of the main valve to open the mouth of the purpose of media distribution. When the coil power, the magnetic force disappears, moving core is reset in the spring force pilot turned off the mouth, this time from the balance of holes into the media, the main valve on the chamber pressure, and under the action of the spring force of the downward movement, Close the main valve port. Open-type principle of just the opposite.
