Fire special signal relisient seat seal GATE VALVE is used in automatic spraying water pipeline in fire protection system to monitor the water supply pipeline and indicate the valve's opening at a long distance. It is often used in fire protection system, and if the installation position is high to the ground, rising stem gate valve is used and can show the valve's opening clearly while if the installation position is low, opening indicator gate valve is used. The main technical paremeters: Nominal pressure: 1.0Mpa, 2.5Mpa; Nominal diameter: 50-400mm; test critaria: GB13927