| 摘要 |
2062957 9100768 PCTABS00003 The present invention relates to a method and apparatus for treating pulp, which method and apparatus are especially suitable for treating fiber suspensions in wood processing industry. The method and apparatus are particularly designed for thickening said suspensions, in other words filtering liquids from fiber suspensions in pulp and paper industry. The invention relates more closely to a so called drum cylinder, the basic construction of which comprises a vessel, into which suspension being thickened is supplied and a wire-surfaced cylinder rotating in the vessel. The drum filter in accordance with the present invention is characterized in that the closing member (40) of the drum filter has a channel (70) for leading gas from the filtrate tubes (24) through the compartments of the distribution chamber (26) to the outside of the closing member (40). The method in accordance with the present invention is characterized in that the operation phase of the filter cylinder is divided into five stages separated from each other, in the first stage, when the cylinder descends into the vessel, air and the initial filtrate are discharged from the filtrate compartments and the formation of the pulp web on the wire surface begins; in the second stage filtrate is discharged with vacuum and the formation of the pulp web continues; in the third stage pulp web is dried by means of vacuum when said part of the web has risen with the cylinder from the vessel; in the fourth stage, a so called removal stage, pulp web is removed from the wire surface and discharged from the apparatus; and in the fifth stage, a so called washing stage, the wire surface is washed.
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