The Double Check Valve Device Assembly (DCVA) – Flow or Dynamic State
As water flows through the DCVA, the inlet or supply pressure opens the first spring loaded check valve. As water fills the area between the check valves, the water pressure opens the second spring loaded check valve. Since, the check valves are spring loaded a pressure loss is created across the first and second check valve. The force of the check valve springs is trying to keep the check valves in a closed position. As water continues to flow through the DCVA due to a downstream demand, a differential pressure across the DCVA is created by the tensile strength of the springs and friction. The greater the flow through the DCVA, the more the check valves will open. The greater the flow velocity, the greater the pressure loss across the DCVA. The springs are force loaded to a minimum of 1 PSI. If a backpressure backflow condition were to occur, both check valves would close tight if not fouled.
