When it comes to getting fluid to flow in one direction, designs like those found in engines have traditionally leaned on flaps. And while human intestines are more or less hollow tubes, shark ...

Inherent control valve flow characteristics are established assuming a constant Δp across the valve. If the valve Δp is reduced as the flow increases, meaning that there is a valve pressure drop decay ...

Check valves use a ball or poppet to prevent flow in one or more directions. In two-port valves, the ball or poppet is usually lightly spring loaded against one of the ports.