Agitator Effectiveness

Not all of these options are practical because of shear, foaming and control devices. 

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The interfacial area in the region with agitation effect N > and Hquid height, F/, is given by... 

Notes tranq. tranquilization effect agit, agitation effect self-agit, self-agitation effect. 

In subcooled flow boiling, a large roughness increases flow agitation and hence improves CHF. If the roughness is smaller than the thickness of the bubble layer, the agitation effect on CHF is insignificant. 

Some examples in which this agitation effect is more likely to occur are reactions during which the viscosity changes significantly, such as in polymerizations, and reactions with suspensions. Equipment dimensions, type of agitators, and type of solvents and coolants used affect the heat transfer as well [174],... 

It Is occasionally seen In a crystallization process that a certain gas Is blown to react with some components of the solution and to yield a crystalline product. The admittance of the gas Into the crystallizer was also expected to promote an agitation effect. 

Dunbar GC, Fuell DL The anti-anxiety and anti-agitation effects of paroxetine in depressed patients. Int Chn Psychopharmacol 6 [suppl 4) 81-90, 1992 Dunleavy DLF, Oswald 1 Phenelzine, mood response and sleep. Arch Gen Psychiatry 28 353-356, 1973... 

Let us deal with regions with and without agitation effect (refer to Challenge 5.3). 

A region without agitation effect and that with agitation effect are defined as follows ... 

Region without agitation effect. At a very low impeller rotational speed, up to a certain minimum impeller rotational speed, the transfer rate does not improve with stirring. In this region, the mass transfer rate depends on the gas load and type of sparger but is independent of the impeller rotation speed. 

Region with agitation effect As the impeller rotational speed exceeds the minimum speed, the mass transfer rate increases quickly and linearly with the increasing impeller rotational speed. 

Glycidyl Adducts of Aliphatic Amines. An aliphatic amine such as diethylenetriamine can be partially reacted with an epoxy, such as a DGEBA resin, to produce a low-volatility adduct. In a typical reaction, the epoxy is added slowly to a large excess of DETA. The reaction is maintained at 75°C by cooling. The reaction products are continuously agitated effectively to provide for good contact and uniform concentration effects. At the end of the reaction, excess DETA is vacuum-distilled away from the adduct. 

Vibrating electrode — Vibrational movements of electrodes create agitation effects and therefore result in conditions of hydrodynamic flow (- hydrodynamic voltam-... 

Convective heat transfer is often used as an adjunct to other modes, particularly to the conductive mode. It is often more convenient to consider the agitative effect a performance-improvement influence on the thermal diffusivity factor a, modifying it to a, the effective value. 

The theoretical agitation effect of aeration alone can be easily calculated. There are two separate forces, the first caused by the free rise of bubbles. The bubbles rise from the sparger at a pressure equal to the hydrostatic pressure of the liquid and as they rise to the surface, the gas bubble pressure remains in constant equilibrium with the hydrostatic pressure above it until it escapes fi om the liquid surface. The temperature of the air in the bubble is equal to the fermentation temperature and remains constant due to heat transfer from the fermentation broth. These conditions describe an isothermal expansion of gas gas pressure and gas volume change at constant temperature. Using the formula from Perry and Chilton,the theoretical horsepower for the isothermal expansion of air can be calculated. 

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