VAG GA Vacuum Breaking Valve Figure 990-D for Clean Water

VAG GA Industries Figure 990-D Vacuum Breaking Valves are air inlet only valves. They are normally closed and automatically open to admit air whenever the pipeline or system pressure falls approximately 0.25 PSI below atmospheric. The valves open as far as necessary to admit air at the rate needed to limit the vacuum condition and re-close when the system pressure recovers above the opening pressure.

Figure 990-D Vacuum Breaking Valves are typically installed at system high points where negative pressure first develops during system draining and/or where column separations are predicted to occur. They can also be installed adjacent to air & vacuum valves or combination air valves to supplement those valves’ air inflow during uncontrolled pipeline draining.