Check valves permit flow in one direction only, and close automatically if flow reverses. They are entirely automatic in action, depending upon pressure and velocity of flow within the line to perform their functions of opening and closing.
Lift Check Valves should only be used in horizontal pipe runs.
The Crane D104 check valve is of the lift variety.
This download include all size variations of the D104 Lift Check Valve by Crane Fluid Systems.