Structural principle of pilot operated solenoid valve

Pilot operated solenoid valve, when powered on, relies on electromagnetic force to lift the valve stem and open the pilot valve port. At this time, the upper chamber of the solenoid valve releases pressure through the pilot hole, forming a high and low pressure difference around the main valve core. Under the action of the pressure difference, the fluid pressure drives the main valve core to move upwards and open the main valve port; When power is cut off, under the action of spring force and main valve core gravity, the valve stem resets, the pilot hole closes, the main valve core moves downward, and the main valve port closes; The pressure in the upper chamber of the solenoid valve increases, and the fluid pressure is pressurized towards the main valve core, resulting in better sealing.