The ZSFZ Wet System Alarm Valve is mainly based on the structural principle of the partition/seat wet system alarm valve. The valve body is made of grey cast iron. The disc and seat are made of copper alloy; the pin axis and internal screws use stainless steel; and the sealing spacer uses Buna-N rubber. The disc connecting part employs a special arc connection, making the disc open and close with flexibility, and well-positioned. An inlet, an outlet, an alarm opening and a testing entrance are set up according to their functional requirements. The ZSFZ Wet System Alarm Valve (DN150) is of the internally-balanced type; the DN100 and DN200 are externally-balanced.