The Zurn Industries shut off valve BVMS (Ball Valve Monitor Switch) is mounted on a backflow preventer’s ball valve shutoffs in a fire sprinkler system, providing electrical supervision of the ball valves. The BVMS signals if/when a ball valve handle is moved from an open position.
It has an internal switch, which is toggled when the ball valve is moved from the open position. However, the internal switch does not track the position of the handle or ball. When the ball valve lever handle is moved into the open position, an internal spring-loaded switch contacts the lever handle and is toggled into the secure position. When the handle is moved from the open position, the switch extends and is toggled into the tripped position. The switch has contacts for both normally open and normally closed operation.
Image credit: Zurn Industries LLC