Graesser extractors

Figure 14.15. A horizontal rotating extractor and two kinds of centrifugal extractors, (a) The RTL (formerly Graesser raining bucket) horizontal rotating extractor both phases are dispersed at some portion of the rotation RTL S. A., London). (b) Operating principle of the Podbielniak centrifugal extractor it is made up of several concentric perforated cylinders (Baker-Perkins Co.), (c) The Luwesta centrifugal extractor (schematic diagram) Luwa Corp.).

Countercurrent columns with additional kinetic energy input have found a broad range of industrial applications [42-48]. Examples of extraction towers with energy input are pulsed towers, pulsed packed columns and pulsed perforated-plate towers. A number of units with some form of mechanical agitation are also used (Karr column, Scheibel column, Oldshue-Rushton column, Ktihni column, RZE extractor, RDC and ARD extractor, Graesser contactor). 

The Graesser contactor takes an extreme position in the diagram. It has the highest separation efficiency (10 stages per meter) but the lowest capacity (1-2 m/h). The other extremum takes the static sieve tray extractor with only one equilibrium stage per meter and up to 50 m/h capacity. The capacity of a pulsed sieve tray column is as high as 30 m/h with a separation efficiency of 5 to 6 stages per meter. 

Extraction apparatus with continuous phase contact Spray column Packed column Pulsed packed column Rotating disc contactor, Oldshue-Rushton column, Graesser-Contactor, Kuhni column Podbiehiiak- Extractor, Luigi-Westfalia- Extractor, De Laval-Extractor... 

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