An apparatus for separating at least two discrete volumes of a composite liquid into at least a first component and a second component, comprising a valve design that facilitates loading and unloading of blood bags and associated tubing and bag sets. The valves comprise a rotating head, mounted on a shaft, which assumes a load position. The head pivots to an open position, which secures the tube in its designated location, but which maintains an open lumen through the tube. When the head is in a closed position, blood components cannot flow through the tube. The valve apparatus comprises means for maintaining a constant pressure on the tube and contact with the tube as the tube is melted and sealed.
