The Principle Operation of an Atmospheric Vacuum Breaker Backflow Prevention Device – Flow Capacity
When the AVB is fully pressurized and there is a demand downstream, (dynamic state) the float disc is open and the air inlet port is closed. The grater the rate of flow (gpm) through the AVB, the grater the check valve will open. As the rate of flow in gallons per minute through the AVB increases, the pressure loss in pounds per square inch increases. Consult manufacture literature or capacity rate for the specific AVB.