20HP to 40HP Minimum Pressure Check Valve Minimum Pressure Valve as some traces of oil

as some traces of oil and vapors may pass through the air filter material and remain in your air supply

there isn't enough centrifugal force to continue

resulting in more efficiency at higher PSI  ranges up to 232 PSI if

it is essential that high performing filters are used

20HP to 40HP Minimum Pressure Check Valve Minimum Pressure Valve as some traces of oilUsually installed on the discharge port of the separator tank, minimum pressure valves are available in a threaded or flanged version. They include a poppet to maintain minimum pressure in the separator tank when the compressor is started and a check valve to prevent air backflow from the line.