Thursday, 13 June 2013

Bollman Extractor OR Basket Extractor

Bollman Extractor OR Basket Extractor

·        One of the very oldest continuous extractor and still listed among the best is the Bollman Extractor.
·        The Bollman Extractor was invented by H. Bollman in Germany in 1920.
·        Bollman Extractor is mainly used for the recovery of additional oil from the residues obtained after mechanical pressing of solids.
·        The Bollman Extractor essentially consists of a vapour tight vertical chamber in which a series of perforated baskets are attached to a chain conveyor.
·        The baskets are provided with perforations at the bottom.
·        At the top right hand corner of the extractor solids are conveyed in to the perforated baskets.
·        The baskets are loaded with flaky solids.
·        These fully loaded baskets are then sprayed with Half Miscella as they travel downward through the right hand side.
·        Half Miscella is the intermediate solvent containing some extracted oil and some small solid particles.
·        As the solids and solvent flow co-currently down the right hand side of the machine, the solvent extracts more oil.
·        Simultaneously the fine solids are filtered out of the solvent, so that the clean full miscella can be pumped from the outlet provided at the right hand bottom.
·        Then as these partially extracted solids rise through the left hand side of the machine a stream of pure solvent is sprayed on them to obtain a dilute solution of the oil (half miscella) at the bottom of the chamber.
·        This pure solvent percolates counter-currently through them and collects in the left hand sump which is then passed to the Half Miscella storage tank.
·        The fully extracted solids are then dumped from the baskets at the top of the elevator to the hoppers from which they are removed by Screw Conveyors.
·        Usually the conveyor speed is one revolution per hour.

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