The Principle Operation of a Dual Check Valve with Intermediate Atmospheric Vent – Backflow Prevention Device – Pressure Loss Across Check Valves Dynamic State
Since the check valves are force loaded, the supply pressure is reduced by the amount generated by for force necessary to close the intermediate atmospheric vent and open the check valves. The maximum allowable pressure loss through the DCVwIV is 25 psi. The pressure loss when the DCVwIV is in a static state will range from 2 psi to 4 psi depending on manufacture. The pressure loss when the DCVwIV is in a dynamic state at 10 gpm will range from 8 psi to 15 psi depending on side and manufacture.