flexible cascade

The two stages of the cleaner system are set up to provide maximum flexibility in the handling of stock, automatically responding to process changes.



Thick stock is fed to the primary cleaner pump in the routine course of paper manufacture. The fan pump flow to the headbox is determined by grade-specific process variables. With a constant pressure drop, the flow through the cleaners is constant.

The function of Flexible Cascade™ arrangement is shown in the adjacent diagram. Accept flows a1 and a2 are delivered to an accept collector, from which the headbox is fed. If the fan pump flow exceeds the primary accept flow (a1), some or all of the secondary accepts (a2) will also be transferred to the fan pump. If the fan pump flow exceeds that of the combined accepts, the system will then draw the necessary additional water (+r) from the POM Header. If the fan pump flow is smaller than the combined accept flows, the excess flow of accepts will be recirculated (-r) to the primary cleaner pump.

The operation of the system is highly flexible, and the flow to the headbox is composed hierarchically of primary accepts, secondary accepts and, if necessary, backwater as re-dilution.

Flexible Cascade™ provides a compact, self-balancing and self-cleaning system, free of dead zones in the accept and reject headers. The use of a common accept line for both stages of cleaning allows all of the cleaners to be run at constant pressure for all operating conditions. Thus, with the flow through the cleaners constant, the plant can be sized to occupy a minimal amount of space, while operating optimally at a low level of energy consumption.