Some types of marine explosion-proof solenoid valves are pipeline accessories of the oil delivery system. They are mainly used for the control of the system refueling switch. They are closed when the power is off, and can be sealed reliably to ensure that the system is leak-free. When the solenoid valve is instructed to open or close, it can be reliably opened and closed, and feedback to the control room through passive contact signal. The flash point temperature of fuel medium used in solenoid valves is 60 C, and the working environment temperature is up to 55 C. It is necessary to ensure that the solenoid suction ensures the reliable switching of valves, and reduce the power of electromagnets to ensure that the surface temperature of solenoid valves does not exceed 60 C.
The solenoid valve is chosen as the pilot normally closed type. When the power is switched off, the solenoid valve is closed and the flow of the medium is blocked. When electrified, the coil produces electromagnetic force, the moving iron core moves upward under the drive of electromagnetic force, the pilot valve opens, the medium of the piston upper chamber is discharged from the pilot seat instantaneously, and the pressure of the piston lower chamber flows into the piston upper chamber through the throttle tube. At this time, the pressure of the piston upper chamber is close to the pressure behind the valve. The pressure of the piston lower chamber acts on the lower end of the piston. The upward force overcomes the reset spring, the piston gravity and friction, and makes the piston move upward to open the valve. When the solenoid valve is powered off, the electromagnetic force disappears. The movable iron core closes the pilot valve under the action of spring force and the gravity of the iron core itself. The medium flows into the piston upper chamber through the throttle tube. When the pressure of the upper and lower chambers of the piston is equal, the piston moves downward to close the valve under the action of the reset spring force and its own gravity. Power and power fail each time to complete the working process of the solenoid valve once. The reed switch forms a signal feedback device. When energized, the normally open contact is absorbed by the magnetic field. When the power is cut off, the magnetic field will disappear and the contact will resume normally.
