Abstract: Apparatus for separating a liquid, such as whole blood, into fractions having different densities includes a separation chamber and a transfer device, such as a continuous piece of flexible tubing, for supplying the liquid to the separation chamber and discharging the liquid fractions therefrom. The separation chamber and the transfer device are conjointly rotated about a first axis which passes through a stationary end of the transfer device, while being simultaneously and conjointly rotated about a second axis which is coincident with a medial longitudinal axis of the rotating end of the transfer device so as to prevent the transfer device from twisting as a result of its rotation about the first axis.

Abstract: A supporting net is disclosed including an outer layer of first strands, said first strands being spaced apart and substantially parallel to each other; an intermediate supporting layer of second strands; and an inner layer of third strands, said third strands being spaced apart and substantially parallel to each other, said third strands being substantially parallel to said first strands and being in a spaced relationship to said first strands such that upon clamping a membrane between said supporting net and a second supporting net of the same construction the first strands of the outer layer of said second supporting net penetrate into the spaces between the third strands of the inner layer of the said supporting net so as to clamp the membrane against the intermediate supporting layers of both of the supporting nets.