| 摘要 |
A paper web is passed between a pair of first and second corrugating rolls to form corrugations therein. The second corrugating roll is provided with a plurality of longitudinally spaced annular suction grooves in communication with a suction device from which subatmospheric pressure is applied through the annular suction grooves to the corrugated web, while it is travelling around the second corrugating roll, retaining the corrugations in the flutes of the roll.
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