Abstract: Fluid cleaning apparatus for precision parts, comprising in combination, a chamber, having a fluid inlet and a fluid outlet, for holding parts to be cleaned and a fluid tight recirculating flow system including the chamber. The fluid tight system directs supercritical carbon dioxide fluid flow across the parts being cleaned. A fluid recirculating cylinder has a first fluid port and a second fluid port connected in the flow system. A fluid piston is in the cylinder between said ports. A pneumatic cylinder has a further piston between a first pneumatic port and a second pneumatic port. A driving member is connected between the pistons for reciprocal movement caused by air from a source alternately introduced to the pneumatic ports to cause the fluid piston to pump fluid through the chamber and back to the recirculating cylinder. A shuttle valve is connected between the air source and the pneumatic ports.