Rotary SealFree FlowThrough Systems

The development of the hydrodynamic CCC systems was initiated by introduction of various flow-through centrifuge systems that can perform continuous elution without the use of conventional rotary seals. A series of such centrifuge systems is schematically illustrated in Figure 3. The diagrams show the

Figure 3 A series of flow-through centrifuge systems free of rotary seals.

orientation and motion of a cyclindrical coil holder with a bundle of flow tubes, the end of which is supported on the centrifuge axis at the point marked with a black dot.

These centrifuge systems are classified in three groups according to their modes of planetary motion. The synchronous schemes (left column) produce a synchronous planetary motion of the coil holder, i.e. one rotation about its own axis during one revolution around the central axis of the centrifuge. In the nonsynchronous schemes (right column) the rates of rotation and revolution of the holder are independently adjustable. The nonplanetary scheme (middle column) produces simple rotation as in the conventional centrifuge system. In the Type I synchronous planetary motion (left, top) the holder revolves around the central axis of the centrifuge and synchronously rotates about its own axis in the opposite direction. This synchronous counterrotation of the holder steadily unwinds the twist of the tube bundle caused by revolution, thus eliminating the need for the rotary seal. This same principle can be applied to other synchronous schemes with tilted (Types I-L and I-X), horizontal (Types L and X), dipping (Types J-L and J-X) or even inverted (Type J) orientation of the holder. The Type J synchronous scheme is a transitional form to the nonplanetary scheme. When the holder of the Type J synchronous scheme is shifted to the central axis of the centrifuge, the rates of rotation (ro) and revolution (ro) of the holder are added and the holder rotates at an angular velocity of 2ro. In this case the tube bundle rotates around the holder at ro in the same direction as that of the holder to unwind the twist caused by the rotation of the holder. This nonplanetary scheme is further transformed to the nonsynchronous schemes. On the base of the nonplanetary scheme, the holder is again shifted towards the periphery of the centrifuge to perform a synchronous planetary motion. By selecting the holder orientation as specified in the synchronous schemes, the respective types of nonsynchronous schemes are produced.

Each scheme produces a specific pattern of the centrifugal force field that can be utilized for performing CCC. Among these, the Type J synchronous planetary motion is found to be most useful since it can perform high speed CCC that yields efficient separations in a short elution time.

Solar Panel Basics

Solar Panel Basics

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