Abstract: A plastic ring has a circumferential groove formed in its outer peripheral surface. The ring is fitted in a bowl-type centrifuge rotor such that the ring's outer surface contacts the inner wall of the rotor. The channel is defined by the groove and rotor wall. The rotor is filled with a compensating liquid to reduce centrifugal stress on the plastic and to reduce leakage from the channel.

Abstract: A free floating plastic channel for sedimentation field flow fractionation is suspended in a centrifuge rotor filled with a compensating liquid. The channel is constructed of a plastic central hub assembly fitted with a plastic outer ring preferably of a lower density than the hub. The hub contains a shallow channel on its outer surface and is interference-fitted to the outer ring to insure a liquid tight seal at zero force field. With the liquid totally surrounding the hub-outer ring assembly, stresses on the plastic parts are essentially equalized even under high force fields and leakage from the channel at the hub-ring interface is greatly reduced.

Abstract: A long, thin annular belt-like channel can be used in sedimentation field flow fractionation. A rotating seal is required to couple fluids to the channel inlet and from the channel outlet. A flexible shaft is used to drive the rotating seal and thereby decouple rotor vibrations, which cause can leakage, from the rotating seal.

Abstract: A long, thin annular belt-like channel is designed for use in sedimentation field flow fractionation. The channel has a generally rectangular cross section and a width to thickness aspect ratio lying in the range of 3-50 to 1. The channel may be formed of a flattened capillary tube. The ratio of the thickness of the channel to the characteristic height of the particles to be separated is greater than 5 to 1.