One Way Valve
Swing Check valves allow water to pass from one direction. Swing check valves are commonly used at the inlet of fill pipe manifolds and stop water rushing out when the camlock is disconnected. The swing disc allows water to pass freely.
Foot valves are installed at the inlet end of a suction hose. They allow water to flow into the hose but not out. Keeping the hose full of water makes priming pump much faster.