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POLYMER
In rare applications, the addition of polymer is indispensable in achieving adequate
screw press performance. Polymers are added to dilute waste streams, especially
to those containing very small size suspended solids. The long chain molecules of
the polymer will flocculate the solids, agglomerating them to the point where they
can be pressed. Under the right conditions, dramatic improvement can be
achieved in press throughput, press cake moisture, and press liquor clarity.
Nalco and GE are the leading polymer suppliers. Their sales engineers are
anxious to recommend the product best suited for your application.
Low speed operation of the press is usually required in order to achieve good
performance.
NOTCHES
Sometimes it is necessary, during press operation, to have the screw wipe the
screens clear of blinding material. This is best achieved by having notches in the
outer edge of the screw. Fibrous material accumulates in the notches and brushes
away slimy material which may be blinding the screens. Shallow notches (1/8"
wide by 1/8" deep, 1-1/2" apart) in the outer edge of the screw flights work well.
Typically, notching is done from the B plate to the second resistor tooth. Most
Vincent presses are supplied with notches.
GRINDING NOTCHES IN THE FLIGHTS
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