Hydrodynamic Equilibrium Systems

In the hydrodynamic equilibrium systems such as the flow-through multilayer coil CPC (Fig. 5) or the horizontal flow-through multilayer CPC, the rotation of the coiled column around its own axis creates an Archimedean screw force which, in combination with a revolutionary centrifugal force towards the center of the centrifuge, allows a Continuous mixing of the two phases while retaining a high proportion of the stationary

Sample Loop

Sample Loop

Rotating Multilayer Coil

Gear Drive

Fraction Collector

Rotating Multilayer Coil

Gear Drive

Counterbalance Rotating

Figure 5. Schematic illustration of the Ito multilayer coil separator-extractor.

Fraction Collector phase. Using a stroboscope, Ito observed that under high centrifugal forces and flow rates the mixing zone, being located near the center of the centrifuge where the centrifugal force is the weakest, travels towards one end of the coil [23]. This indicates that the two phases are subjected to a partitioning process of repetitive mixing and settling at a rate of 13-16 times per second under a revolutional speed of 800-1000 r.p.m. when the mobile phase is steadily passing through the stationary phase. All these features assure a high partition efficiency and a high retention capability of the stationary phase under a high flow rate of the mobile phase in comparison with the hydrostatic equilibrium systems.

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