Pre-action automatic sprinkler systems are usually composed of pre-action devices (pre-action alarm valves, control devices, air pressure maintaining devices, air supply devices, etc.), transmission systems, pipe networks, closed sprinklers, water source control valves, and signal valves. When the pre-action system is in a servo state, the pipe network is filled with low-pressure air to monitor the sealing of the system pipe network. When a fire alarm occurs in the protected area, the detection system first acts to open the pre-actuation deluge valve and the electric exhaust valve used for exhaust in the system.
At this time, the system begins to fill water and exhaust, thereby turning into a wet system, if the fire continues development, closed sprinklers open, spray water to extinguishing the fire. This overcomes the defect that the deluge system may be mistakenly sprayed due to a malfunction of the detection system. If any sprinkler glass ball accidentally breaks in the system, the gas will be ejected from the sprinkler head, which will cause the air pressure in the system to drop rapidly. Then the low-voltage monitor switches, an alarm signal will be issued to alert the on-duty personnel of abnormal conditions, but the pre-acting deluge valve does not open, so the system will not spray water, thus overcoming the drawback that the wet system may cause water damage due to misuse of the sprinkler.

Pauline Lu 

Head of sales Department “SANJING FIRE ”

Phone/Skype/Whatsapp/Wechat: +86-13332933886

Manager@Sanjingfire.com