Patent ID: 7141139

Claim:
A process for directing a papermaking pulp, comprising a liquid and components of a more solid character, said process comprising directing said pulp towards a regulated outlet, whereby said pulp is led via a feeding pipe to a first cleaning stage from which an accept is primarily led towards said outlet, wherein reject from said first cleaning stage is led for further treatment to a respective inlet of at least one succeeding cleaning stage, whereby the accept from said first cleaning stage as well as accept from said at least one succeeding cleaning stage is induced, in turn, to be directed completely or partly towards said outlet while those portions of said accept which are not directed towards said outlet are induced to be directed in the opposite direction towards said feeding pipe to said first cleaning stage; wherein the accept from at least two successive cleaning stages is led to a base pipe, which is common for respective cleaning stages and which leads in one direction to said outlet and in the other direction towards an inlet for pulp to said first cleaning stage, whereby regulating devices, optionally a pump, are utilized for allowing the flow in the common base pipe to be distributed so that it primarily flows towards said outlet and secondarily flows in the opposite direction towards said inlet, while pump means are used as regulating devices at the respective inlets to the respective cleaning stages in order to maintain a substantially continuous flow through the respective cleaning stages; wherein diluting liquid is introduced for being mixed with the pulp at a point which is situated between that end of a base pipe which is connected to said inlet, in the flow direction ahead of pump means, and the pipe sections to which accept from said at least one succeeding cleaning stage is fed; and/or wherein diluting liquid is introduced, for being mixed with the pulp, to one end of the collecting reject pipes, which pipes at the other end, in the flow direction ahead of pump means, lead the pulp and any diluting liquid introduced therein to the inlet of the respective succeeding cleaning stage; and wherein said pulp is forwarded to a forming wire in a papermaking machine.