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.
