METHOD AND PROCESS ARRANGEMENT IN THE SHORT CIRCULATION OF A PAPER MACHINE
A process arrangement in the short circulation of a paper machine comprises devices (10-13) for dilution of thick stock, centrifugal cleaners (14), and a headbox fan pump (16), as well as a pipe system connecting these. There is a direct flow connection from the centrifugal cleaners (14) along a pipeline (30) to the headbox fan pump (16), through which pipeline (30) a centrifugally cleaned stock flow (F6) is passed direct to the headbox fan pump (16) without any deaeration or dilution stages in between. A secondary line (32) is connected to the pipeline (30) for passing through it part of the centrifugally cleaned stock flow as a return flow (F7) back to the thick stock dilution devices (10-13). By this arrangement it can be ensured that the pressure on the suction side of the fan pump (16) remains substantially constant.