Method for converting an up-flow tower for cellulose pulp to a down-flow tower

1. A method for storing and treating cellulose pulp having a medium consistency in a range of 8-16% and for converting a vertically standing up-flow tower used for storage or treatment of the pulp, comprising: providing an up-flow tower having an inlet centrally defined therein at a bottom of the tower that is transitioned to a conical inlet part at the bottom of the tower, the tower having an outlet defined therein at a top of the tower, inserting a pipe into the inlet part of the tower, the pipe having an upper open end disposed a first distance (A) from a lower part of the conical inlet part, the first distance (A) being shorter than a total vertical extension (B) of the conical inlet part, feeding cellulose pulp in through the outlet and discharging the cellulose pulp through the inlet so that the up-flow tower is converted to a down-flow tower, and the cellulose pulp forming a stagnation zone around the pipe and in the whole of a lower part of the down-flow tower below the upper end of the pipe.

2. The method according to claim 1 wherein the pipe is inserted into the conical part of the tower so that the first distance (A) is about 50-85% of the second distance (B).

3. The method according to claim 2 wherein a number of first nozzles are arranged for adding a dilution liquid to a peripheral conduit of the tower at a first level and arranged to end in the tower above an upper open end of the pipe.

4. The method according to claim 3 wherein a number of second nozzles for adding dilution liquid are arranged in the peripheral conduit of the tower at a second level and arranged to end in the tower below an upper open end of the pipe.

5. The method according to claim 1 wherein the pipe is inserted into the conical part of the tower by pulling the pipe downwardly in small steps until plugging occurs and then pushing the pipe up a distance so that a margin against plugging can be established at the current consistency.