Anti-vacuum Valve

The Anti-Vacuum Valve is a very special type of air valve. It's primary function is to prevent the formation of vacuum in hydroelectric penstocks or large diameter water mains, which might cause line collapse under such conditions of flow as may result, for example, from too rapid a closure of an upstream head gate or shut down valve, a downstream burst, turbine "runaway" or ordinary emptying of a pipeline.

By virtue of its unique design, the anti-vacuum valve reacts automatically, sensitively and positively, even after long period of inactivity, to changes of pressure within a pipe, and whenever necessary, permits air to flow in at a sufficiently high velocity, and at a low enough induction pressure, to safeguard the line against collapse.