Nozzle check valve or non slam nozzle check valve

A check valve typically used with compressor discharge, pump discharge, bypass, etc.​
It requires a very low flow to fully open, has a low pressure drop and closes very quickly.​
Where other check valves are ordered based on the line size these valves typically require a calculation to determine the correct size and design of the internals to ensure it matches the process so it will do what is expected.