Parker D04B2-0.2N ball type check valve 42 GPM

Parker ball type check valves are designed with a ball held against a seat by a spring. This prevents flow in one direction at all times, but permits flow in the opposite direction when the pressure is high enough to lift the ball off its seat. The pressure at which reverse flow is permitted is called the cracking pressure. By using a hardened ball and finished seat, leakage rates are less than 5 drops per minute in the blocking direction.