| 摘要 |
Apparatus for thickening papermaking pulp in water has a pair of spaced-apart rolls (20, 22) and a woven wire belt (30) trained around these rolls. The pulp is supplied at the first roll (20) for centrifugal extraction and is carried by the belt to the second roll (22) for further water extraction and thickening, and is then discharged from the apparatus. In one embodiment, the first roll (20) is formed with an open surface, and the suspension is delivered to the web at least partially by flowing through the first roll from a headbox (40) in the on-running wedge zone or a headbox (82) internal to the roll to deliver stock outwardly through the roll. A second roll (22) is porous and has auxiliary water-removing appliances associated therewith, including blow boxes (110, 120, 132) for forcing air either inwardly or outwardly of the second roll, and an auxiliary nip roll 1155) for creating a zone of higher compression for mechanical extraction of water from the mat of pulp between the belt and the second roll. Rewetting of the mat caused by water entrained in the wire mesh cavities is reduced by the impingement of air jets (150) to remove such water. One or both rolls may include a pair of disks (205) spaced apart on a support shaft with the wire belt trained over the outer surfaces of the disks so that a substantial open extent of the belt is defined between the disks. The rolls may be mounted with the plane defined by their axes in any desired spatial orientation, from horizontal to vertical.
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