A centrifuge includes a housing that defines a fluid inlet port to supply fluid to the centrifuge and an axle cavity fluidly coupled to the fluid inlet port. A bearing is received in the axle cavity. A check valve is disposed in the axle cavity to minimize tampering, and the check valve is configured to control flow of the fluid from the inlet port. A rotor is configured to separate particulate matter from the fluid. The rotor includes an axle rotatably received in the bearing, and the axle defines a fluid passage to supply the fluid to the rotor. The check valve is normally biased towards a closed position where the flow of the fluid is shutoff. The axle is configured to open the check valve when the axle is received in the bearing.