| 摘要 |
The present invention relates to a dewatering device for dewatering material suspensions. The device comprises two cylindric rotary rolls (1), which between themselves form a nip (2), through which the material is intended to pass downward from above and thereby be dewatered. According to known art a doctor abuts the liquid permeable roll (1) after the nip. The doctor and als o the roll (1) get worn. Problems also often arise due to re-wetting of the dewatered material. According to the invention the doctor is replaced by a screen device (11) located below the nip and comprising at least one screen (12). The screen extends along the entire length of the roll, and its uppermost portion (13) is located closest to the roll (1). The distance between the uppermost portion (13) and the roll (1) is so great that a filtrate liquid film (10) formed after the nip can pass inbetween the roll ( 1) and uppermost portion (13) of the screen before the filtrate liquid film (10 ) leaves the roll (1). The screen (12) is located so that the filtrate after having left the roll (1) is prevented from re-wetting the dewatered material .
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