Automatic sprinkler system is one of the fixed fire extinguishing systems with the most extensive application and the highest fire extinguishing efficiency. The automatic sprinkler system is composed of sprinkler head, alarm valve group, water flow alarm device (water flow indicator or pressure switch), pipeline and water supply facilities, and can spray water in case of fire. It is composed of wet alarm valve group, closed sprinkler, water flow indicator, control valve, end water test device, pipeline and water supply facilities. The pipeline of the system is filled with pressurized water. In case of fire, spray water immediately after the sprinkler acts.