NC State


An apparatus for studying the dynamic compression of saturated paper sheets is described. The apparatus can generate various combinations of haversine and square wave press pulses. The dewatering during a full loading cycle is studied, that is in both the compression and expansion phases. The total applied load, the hydraulic pressure and the thickness of the sheet are simultaneously recorded during the pressing operation. A total pressure of 10 MPa can be applied in pulses of durations as low as 5 ms. The techniques for hydraulic pressure and thickness measurement are examined. The performance of the apparatus is demonstrated and results from press tests with sheets of different grammages and different degrees of beating are given.

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