Shearing action

The rotating-disk contactor (RDC), developed in the Netherlands (158) in 1951, uses the shearing action of a rapidly rotating disk to interdisperse the phases (Eig. 15b). These contactors have been used widely throughout the world, particularly in the petrochemical industry for furfural [98-01-1] and SO2 extraction, propane deasphalting, sulfolane [126-33-0] extraction for separation of aromatics, and caprolactam (qv) [105-60-2] purification. Columns up to 4.27 m in diameter are in service. An extensive study (159) has provided an excellent theoretical framework for scale-up. A design manual has also been compiled (160). Detailed descriptions and design criteria for the RDC may also be found (161). 

Controlled Stress Viscometer. Most rotational viscometers operate by controlling the rotational speed and, therefore, the shear rate. The shear stress varies uncontrollably as the viscosity changes. Often, before the stmcture is determined by viscosity measurement, it is destroyed by the shearing action. Yield behavior is difficult to measure. In addition, many flow processes, such as flow under gravity, settling, and film leveling, are stress-driven rather than rate-driven. 

In dipping generally, but particularly with the anode process, it is desirable to use tanks that circulate the coagulant and latex compound, particularly the latter. Use of circulation keeps the Hquid surface clean and free from lumps, scum, or bubbles. Mechanical circulation can cause mbber particle instabihty, however, and eventually coagulate the compound. Therefore, tanks should be designed to minimize friction or shear action, and the compound stabilized to maintain mechanical stabiUty. 

Viscosity is the shear resistance between adjacent fluid layers. Consider in Fig. 4.1 the shearing action between two parallel planes, each of area A, separated by a distance Y. The tangential force F for a given area required to slide one plate over the other at a velocity (v) parallel to each other is... 

Shearing action very good at high speed, but not generally used for this purpose. 

Removoble Arm Rodiol Propeller Agitator,Giving Excellent Shearing Action and Rapid Overturning of the Liquor,Selfcleaning in Operation... 

Accentuate the direct mechanical shearing action of the mixing impeller upon the fluid. 

The male fitting has a cone-shaped surface with the same angle as the inside of the flare. The sleeve supports the tube so vibration does not concentrate at the edge of the flare and distributes the shearing action over a wider area for added strength. 

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