An apparatus for processing pulp comprising a device for preventing the rewetting of pulp in the apparatus, the apparatus further comprising at least one drum rotatable about an axis of rotation and provided with an outer surface permeable to liquid and a plurality of filtrate channels , which extend along the axial extension of the drum and are provided inwardly of the outer surface , the apparatus receives the pulp on the outer surface of the drum and processes the pulp situated on the outer surface while rotating the drum , and the apparatus processes the pulp by at least removing liquid from the pulp and transporting the liquid from the pulp to the filtrate channels through the outer surface , each filtrate channel being adapted to discharge liquid therefrom and being defined by at least a radially outer wall , said device being installed in one of the plurality of filtrate channels , and the device comprising: an axially extending filtrate barrier , which is positioned towards the radially outer wall of the filtrate channel to prevent the flow of liquid from the trailing part of the filtrate channel to the outer surface of the drum , and at least one axially extending support element connected to the filtrate barrier , characterized in that the device comprises at least one biasing member , which connects the filtrate barrier to the at least one support element , the biasing member being adapted to bias the filtrate barrier away from the support element to a first unbiased position, in relation to the support element , at which an extended transverse extension of the device is provided, wherein an extended distance between the filtrate barrier and the support element is provided, and when the device is installed the biasing member being configured to bias the filtrate barrier towards the radially outer wall of the filtrate channel , and in that the biasing member is adapted to bias the filtrate barrier away from the support element when the device is installed in the filtrate channel to a biased position, wherein the biasing members are compressed and in a biased state, and in that the biasing member is adapted to bias the filtrate barrier away from the support element to at least one second unbiased position, in relation to the support element , at which a reduced transverse extension of the device is provided, whereby the device is axially insertable into and removable from the filtrate channel . an axially extending filtrate barrier , which is positioned towards the radially outer wall of the filtrate channel to prevent the flow of liquid from the trailing part of the filtrate channel to the outer surface of the drum , and at least one axially extending support element connected to the filtrate barrier , characterized in that the device comprises at least one biasing member , which connects the filtrate barrier to the at least one support element , the biasing member being adapted to bias the filtrate barrier away from the support element to a first unbiased position, in relation to the support element , at which an extended transverse extension of the device is provided, wherein an extended distance between the filtrate barrier and the support element is provided, and when the device is installed the biasing member being configured to bias the filtrate barrier towards the radially outer wall of the filtrate channel , and in that the biasing member is adapted to bias the filtrate barrier away from the support element when the device is installed in the filtrate channel to a biased position, wherein the biasing members are compressed and in a biased state, <EOS>