Some models of marine explosion-proof solenoid valves are pipeline accessories for oil transportation systems, mainly used for switch control of system refueling. When power is off, they are in a closed state and can be reliably sealed to ensure that the system is leak free. When the solenoid valve receives the command to open or close, it can reliably open and close, and feedback to the control room through passive contact signals. The flash point temperature of the fuel medium used in the solenoid valve is 60 ℃, and the maximum working environment temperature is 55 ℃. It is necessary to ensure the electromagnetic suction force to ensure the reliable opening and closing of the valve, and to reduce the power of the electromagnet to ensure that the surface temperature of the solenoid valve does not exceed 60 ℃.
The solenoid valve is selected as a pilot normally closed type, which is in a closed state when power is cut off, blocking the flow of the medium. When powered on, the coil generates electromagnetic force, and the moving iron core moves upward under the drive of the electromagnetic force. The pilot valve opens, and the medium in the upper chamber of the piston is instantly discharged from the pilot valve seat. The pressure in the lower chamber of the piston flows into the upper chamber of the piston through the throttling conduit. At this point, the pressure in the upper chamber of the piston is close to the pressure behind the valve, and the pressure in the lower chamber of the piston acts on the lower end of the piston. Its upward force overcomes the reset spring, piston gravity, and friction, causing the piston to move upward to open the valve. When the solenoid valve is powered off, the electromagnetic force disappears, and the moving iron core closes the pilot valve under the action of spring force and the weight of the iron core itself. The medium flows into the upper chamber of the piston through the throttling conduit. When the pressure in the upper and lower chambers of the piston is equal, the piston moves downward under the action of the reset spring force and its own gravity to close the valve. Power on and power off once each to complete the first working process of the solenoid valve. The reed switch constitutes a signal feedback device. When powered on, the normally open contacts are attracted by the magnetic field. When the power is cut off, the magnetic field disappears and its contacts return to a normally open state
