Abstract: A fluid flow apparatus includes a peristaltic pump rotor mounted to a deck module assembly. A disposable software set is provided which includes a cassette which has a primary flexible tube and a pump platen adjacent to which the primary flexible tube resides. Tubing with blood processing bags are coupled to the manifold along with the input port of the rotor of a disposable blood processing centrifuge bowl. The cassette is removably secured to the hardware apparatus such that the flexible tube contacts both the platen of the cassette and the rollers of the pump rotor. The pump rotor is rotated to induce a fluid flow through the primary flexible tube. The software set also includes a three-to-one manifold which connects the primary tube to a plurality of secondary flexible tubes. Fluid flow through the secondary flexible tubes is controlled by a plurality of pinch valves which pinch the secondary tubes closed against closing surfaces on the cassette.