Basket extractors

As the baskets traveled across the top, they were inverted momentarily to dump the extracted solids into a discharge hopper. The baskets then continued to the filling station to make another circuit through the extractor. These early vertical basket extractors (Figure 21) were taU and bulky, subject to chain breakage, and were difficult to service. 

An advantage of a multistage, countercurrent basket extractor, in contrast to the two-stage vertical unit, is that the rich miscella, after it has contacted the incoming flakes, can make one final pass thruogh a basket where the flakes have already settled down to form a bed. This effectively filters the miscella and eliminates... 

Anderson Co. (Cleveland, Ohio) came out with a horizontal basket extractor (201) in which the baskets were pushed through a rectangular chamber by means of four externally mounted hydraulic rams. Each ram pushed a row of baskets in sequence to cause the baskets to travel, one-by-one, under each successive spray head. 

FIGURE 10.3-5 French slalionaty basket extractor. (Reproduced by permission, French Gil Mill Machinery Co.)... 

FIGURE 10.3-10 Bollmen vertical basket extractor. (Reproduced by patraission. Chemical Engineering Progress. American Institute of Chemical Engineers.)... 

In continuous and fixed-bed extractors there is a critical through pot rate beyond which flooding will occur. The viscosity of extract usually iucreases as it moves toward the fresh solids end of extraction systems. Houce, in crossflow extractors nod slalioanry-basket extractors, progressive changes in recirculation rates may have to he used to compensate for such changes in viscosity. 

E-1 Raw Flake Elevator E-2 Extractor Feed Convenor -3 Stationary Basket Extractor E-4 Spent Flake Elevator E-S Desolventiter Toaster E-6 Vapor Scrubber... 

E-71st Stage Evaporator E-81st Stage Condenser E-3 Stationary Basket Extractor E-S 2nd Stage Evaporator E-4 Spent Flake Elevator E-10 2nd Stage Condenser... 

A second type of extractor widely used on soybeans is the deep-bed (34 m deep), rotary-basket extractor (Fig. 11.13), such as the Reflex extractor marketed by Desmet Ballestra. Countercurrent solvent-to-flake flow is accomplished by rotating the baskets of flaked material while the solvent and miscella sprays, the miscella collection cells, and the marc discharge remain stationary. The bed is divided into cells or baskets to prevent back mixing of oil-lean miscella with oil-rich miscella. The drained marc discharges when the basket rotates to the position above the discharge hopper. 

Fig. 11.13. Depiction of a deep-bed, rotary basket extractor ("Reflex" extractor, Desmet Ballestra North America, Marietta, GA).

In the French Oil Machinery Co. stationary basket extractor (Fig. 10.3-5), extract percolates through beds of solids contained in a circular array of sector-shaped compartments with perforated bottoms and drains into sumps positioned below the beds. Unlike crossflow extractors, the solids do not move." Instead, the solid feed spout and solids discharge zone rotate about the circle and the extract feed and discharge connections are switched periodically. These extractors are like automated diffusion batteries in which downflow is used but, because extract backmixes in each sump, the extract concentration leaving a stage is somewhat different from that entering the next stage. 

The French stationary-basket extractor is a variant of this. The flakes are contained in stationary, compartmented beds filled by a rotating spout to feed the solids and are leached with solvent and miscella countercurrently [15, 33]. 

Fig. 8.8. Cutaway drawing of French Stationary Basket Extractor. The deepbed baskets are stationary while the collet/flake loading, extraction, drainage, and unloading stations revolve. By permission of French OH Machinery Co., Piqua, OH.)...

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