Total immersion extractors

The Hildebrandt total-immersion extractor is shown schematically in Fig. 18-80. The hehx surface is perforated so that solvent can pass through countercurrently. The screws are so designed to compact... 

Total Immersion Extractors. In a total immersion extractor, the solid material is immersed in and travels through a pool of solvent. The Hildebrand extractor of 1931 (188-190) is an early example. Hildebrand s extractor consisted of two vertical mbes connected at the bottom with a horizontal mbe. All three tubes were filled with solvent. Three screw conveyors moved the solid material down one tube, across the bottom, and up the other tube. Solvent entered near the top of the solids discharge tube and overflowed the solids inlet tube. This flow pattern caused the extracted oil to move away from the solids in a countercurrent fashion. The screws, however, were rough on flakes and produced many fines. 

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