Normally closed solenoid valves, after electrify coil, armature under the effect of electromagnetic force to drive the valve plug, fluid by the deputy valve on the main valve cup run, reduce the pressure effect on the main valve cup, when the main valve cup pressure was reduced to a certain value, the armature drives the main valve cup, and by using pressure difference and make the main valve cup opening, medium circulation.After the coil is cut off, the electromagnetic force disappears, and the armature is reset due to gravity.At the same time, depending on the medium pressure, the main and auxiliary valves can close tightly.
When the pressure rises to a certain value, the pressure difference between the upper and lower pressure of the main valve cup is the same. As a result of the electromagnetic force, the moving iron core pushes the main valve cup under and presses the main valve seat and closes the valve.Coil power off, electromagnetic suction is zero, the deputy valve plug and due to the spring action of moving iron core lift, vice valve is opened, the fluid by the deputy valve on the main valve cup run, reduce the pressure effect on the main valve cup, when the main valve cup pressure was reduced to a certain value, the use of differential pressure push the main valve cup, the main valve opens, medium circulation.