Air aided exhausting pipeline with pressure stop valve

A centrifuge assembly (20) for processing a flow of oil so as to separate out particulate matter includes a centrifuge (20b), a housing base (10), and a flow-control piston (32) which is assembled into the housing base (10). The centrifuge (206) includes a housing which defines a hollow interior with a centrifugal separator positioned within the hollow interior for separation of particulate matter from the flow of oil. The housing base (10) defines an incoming oil conduit (23), a drain conduit (24), an air-in passageway (25), and air-out passageway (26). The flow-control piston (32) is movable between a normally-closed piston and an open position in respect to incoming oil pressure. When in the closed position, neither oil nor air are able to flow into the centrifuge assembly (20). In the open position, both oil and air are able to flow into the centrifuge assembly (20). The air which is introduced is under pressure and provides air-assisted drainage of the oil from the centrifuge (20b) housing back to sump.