The core component of the circulating automatic sprinkler system is the water flow control valve. Its working principle is that when a fire breaks out at the scene, the temperature sensor installed at the fire scene acts because of the rising temperature at the scene. After receiving the signal from the temperature sensor, the control panel immediately starts the solenoid valve to drain and exhaust. Due to the limited water supply of the orifice plate installed on the pressure balance pipe, the pressure balance on both sides can no longer be maintained, and part of the water pressure on the water flow control valve is out of balance. Therefore, the disc of the water flow control valve is in the state of being opened by pressure water, and the water supply enters the water spraying pipe network. Once the nozzle is opened, it can quickly come out to put out the fire. Automatic sprinkler system is a kind of pre-action automatic sprinkler system that can be turned on and off repeatedly, that is, it can be turned off automatically and turned on again after the fire is extinguished. The system can be used in places where water spraying must be stopped in time after fire extinguishing.