HOW IT WORKS
Depending on the applications, the presses can be fed from 2% up to 10% feed consistency. What is unique about the COMPACT PRESS in the ANDRITZ washer range is the high discharge consistency – around 30% from the machine, which is beneficial when separating mill waters from the acidic stage to the alkaline stage.
Uniformity of pulp is very important when creating an efficient process, and it is essential to have distribution of pulp evenly spread across the perforated drum. This even distribution is ensured by unique, specially designed screws that are speed controlled so the transport capacity is adjusted to meet the needs of the pulp fed into the machine.
The COMPACT PRESS enables high consistency starting at the dewatering phase where consistency of the pulp is increased by a converging gap between a perforated drum and the static sliding surface of the press. When the consistency has been increased, the wash liquor is then added in two zones. The benefit of the increased consistency means there is less free liquid in the pulp to displace and the wash liquor is used more efficiently, thus saving on chemical costs.
The second phase of the of washing takes place when the pulp is distributed across the full width of the perforated drum and the wash liquor is distributed via a large number of nozzles in two zones to ensure maximum displacement.
The final pressing is done between the two drums where the pulp is pulled by the perforated drum through the press nip where the free liquid is squeezed out. Another unique feature of COMPACT PRESS is the integration of the dilution screw into the press itself, which eliminates the need for a separate dilution screw or device and makes the layout more compact and efficient.