Working Principle：
DF model solenoid is a kind of indirect common closing diaphragm solenoid valve, which attracts the armature to open the accessory valve orifice when the winding is switched on, which causes the upper pressure decrease and produce a pressure difference, and it pushes the diaphragm of the main valve open to form a electrified circuit; when the winding is switched off, the armature close the accessory valve orifice by the spring force and meanwhile, the medium enters the upper part through the restriction orifice, and thus the pressure increases and the diaphragm tightly press the main valve's orifice to make the main valve closed.