Boundaries to Normal Operation (cont’d)
High Flow: The upper flow boundary is limited by the maximum pressure the press
headbox is designed to withstand (29 psi). The size of the orifices may limit the flow
that can be pumped to the press without exceeding this pressure.
High Consistency: The upper boundary for consistency is limited by the feed system
design, not the press or its headbox.
Low Consistency: The lower consistency limit is the least critical of the four
boundaries. Typically going below this incurs more fiber into the filtrate system
(which will cause a separate set of problems elsewhere), and at high flows will have a
tendency to make fibers stick into the holes of the press rolls and be difficult to clean
(begins to blind, reducing drainage rates, high vat pressure, etc.).