| 摘要 |
The draw-roller unit has only one suction roller as a draw roller, in which a constantly acting suction effect is effective along that circumferential portion round which the paper web is looped, whilst the remaining circumferential portion experiences no suction effect. The suction roller has a fixed hollow roller core and a roller casing rotatable about this and consisting of plastic-impregnated carbon fibres, with suction ports distributed over its circumference. The roller core is equipped, on its one side, with an axial connection piece for fastening to the machine stand and for connection to a vacuum source, on its other side with a bearing journal and, on its circumference having passage orifices with two radial partition walls which are arranged at a specific angular distance from one another and which enclose a suction chamber between them. The roller casing is mounted on the bearing journal by means of a conical connecting flange fastened directly to the rotor shaft of the drive motor and is mounted with its other end on the connection piece, the gaps between roller casing and partition walls being approximately airtight. Instead of a suction roller, a draw roller subjected to compressed air on the outside along the said circumferential portion can also be provided, or else the suction-air and compressed-air effects are combined.
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