Structure and principle of solenoid valve for water

For normally closed solenoid valve, after the coil is energized, the armature first drives the auxiliary valve plug to lift under the electromagnetic force, and the fluid on the main valve cup flows through the auxiliary valve, reducing the pressure on the main valve cup. When the pressure on the main valve cup decreases to a certain value, the armature drives the main valve cup, and uses the pressure difference to open the main valve cup and circulate the medium. After the coil is powered off, the electromagnetic force disappears and the armature is reset due to its own weight. At the same time, depending on the medium pressure, the main and auxiliary valves can be closed tightly.

For the normally open solenoid valve, due to the suction effect after the coil is powered on, the moving iron core moves down, the auxiliary valve plug is pressed down, the auxiliary valve is closed, and the pressure in the main valve cup rises. When the pressure rises to a certain value, the pressure difference between the upper and lower parts of the main valve cup is the same. Due to the action of the electromagnetic force, the moving iron core pushes the main valve cup down, compresses the main valve seat, and the valve is closed. When the coil is powered off, the electromagnetic suction is zero, the auxiliary valve plug and moving iron core are lifted upward due to the spring action, the auxiliary valve is opened, and the fluid on the main valve cup flows through the auxiliary valve, reducing the pressure on the main valve cup. When the pressure on the main valve cup is reduced to a certain value, the main valve cup is pushed up by the pressure difference, the main valve is opened, and the medium flows.