a valve body having an inlet end through which air enters said check valve and an outlet end through which air exits said check valve, and a valve cavity within said valve body extending between about said inlet end and about said outlet end;

a valve assembly located at a position with respect to said valve cavity which enables said valve assembly to control the flow of air through said valve cavity, said valve assembly including a plug having at least a tapered section, said tapered section having a cross section that increases in diameter in a direction that is downstream from said inlet end;

said valve assembly having an elastomeric seal that is mounted around said tapered section to reciprocate on said tapered section, said tapered section biasing said elastomeric seal to a normal position in sealing contact with said valve body and said tapered section to prevent air from flowing downstream from said inlet end and out said outlet end;

said valve assembly allowing air to flow downstream from said inlet and out said outlet end of said valve body when the air compressor produces an amount of air pressure necessary to create a force against said elastomeric seal that is sufficient to cause said seal to be located at a position away from said valve body along said tapered section and to create a preselected clearance between said valve body and said seal; and

the portion of said valve cavity, between about said inlet end and about the location where said elastomeric seal contacts said valve body, having a minimum cross sectional area that allows the pressure of the air flowing through said preselected clearance to be sufficient to continuously remove air from said valve cavity to prevent substantial accumulation of back pressure produced by the air compressor upstream of said valve when repeated cycles of the compression cylinder of said air compressor repeatedly cause said seal to be located at a position away from said valve body and create the preselected clearance between said valve body and said seal.