Centrifugal force industrial centrifuges

The first differential centrifugal extractor to be used in industry was the PodbieHiiak extractor which was introduced in the 1950s (209,210) and can be regarded as a perforated-plate column wrapped around a rotor shaft. Rotation creates a centrifugal force which results in a great reduction in the equivalent height and contact time that would be needed in a conventional perforated-plate column. 

Thin-Film Evaporators. There are two types of thin-film evaporators commonly used in industrial appHcations. The first type introduces feed material into the center of a rotating heated conical receiver. Centrifugal force causes the feed to travel to the outer edge of the conical receiver where it is coUected and drawn off as residue. During the process, the heat causes the volatile components to be driven from the feed. These volatile components are condensed on a chilled surface of the evaporator and coUected as distUlate. 

When rotation occurs, static imbalance translates into a centrifugal force. As a result, this type of imbalance is sometimes referred to as force imbalance and some balancing machine manufacturers use the word force instead of static on their machines. However, when the term force imbalance was just starting to be accepted as the proper term, an American standardization committee on balancing terminology standardized the term static instead of force. The rationale was that the role of the standardization committee was not to determine and/or correct right or wrong practices, but to standardize those currently in use by industry. As a result, the term static imbalance is now widely accepted as the international standard and, therefore, is the term used in this chapter. 

Differences in mobilities of ions, molecules, or particles in an electric field can be exploited to perform useful separations. Primary emphasis is placed on electrophoresis and dielectrophoresis. Analogous separation processes involving magnetic and centrifugal force fields are widely applied in the process industry (see Secs. 18 and 19). 

The need to separate solid and liquid phases is probably the most common phase separation requirement in the process industries, and a variety of techniques is used (Figure 10.9). Separation is effected by either the difference in density between the liquid and solids, using either gravity or centrifugal force, or, for filtration, depends on the particle size and shape. The most suitable technique to use will depend on the solids concentration and feed rate, as well as the size and nature of the solid particles. The range of application of various techniques and equipment, as a function of slurry concentration and particle size, is shown in Figure 10.10. 

In most industrial applications, multistage countercurrent contacting is required. The hydrodynamic driving force necessary to induce countercurrent flow and subsequent phase separation may be derived from the differential effects of either gravity or centrifugal force on the two phases of different densities. Essentially there are two types of design by which effective multistage operation may be obtained ... 

The industrial application of solvent extraction is a mature technique, and it is now possible to move from laboratory experiments on a new extraction system to full industrial practice with little technological risk. There is a sufficient variety of large-scale equipment available to cope with most problems encountered in application, although much of the equipment remains rather massive. Attempts to miniaturize, for instance, by using centrifugal forces to mix and separate phases, still has to be developed further. 

Industrialization and need for increase in agricultural activity, 1-2 Inosine monophosphate, taste enhancer, 17,19 Interdroplet forces, effect on centrifugal stability for protein-stabilized oil-in-water emulsions,... 

Spin coating utilizes centrifugal forces created by a spinning substrate to spread a liquid evenly over its surface. Current applications are in photoresist technology for the microelectronic industry and in the manufacture of... 

One of the more advanced of the FFF techniques is sedimentation FFF (SdFFF), in which the applied field is a centrifugal force (see Fig. 2.1b). A typical separation achieved through SdFFF is also illustrated in Figure 2.1b. The SdFFF is suitable for species with molecular weights larger than about 106 and has proved useful for a large number of biocolloids (e.g., subcellular particles), polymers, emulsions, and natural and industrial colloids (Giddings 1991). 

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