Waste paper recycling apparatus

Abstract

The control unit operates the stirring device sequentially in a defiberization operating mode, a transition operating mode, and a dilution operating mode. In the defiberization operating mode, the stirring blade is rotated at the revolution speed for defiberization of waste paper in the disaggregating water stored in the stirring chamber to generate a waste paper pulp slurry. In the transition operating mode, the dilution water from the water supply unit is supplied to the waste paper pulp slurry while rotating the stirring blade at the revolution speed for defiberization to stir the waste paper pulp slurry. In the dilution operating mode, the dilution water from the water supply unit is supplied to the waste paper pulp slurry while rotating the stirring blade at the revolution speed for stirring, lower than the revolution speed for defiberization, to stir the waste paper pulp slurry.

What is claimed is: 
     
         1 . A waste paper recycling apparatus comprising:
 a plurality of processing units configuring a waste paper processing system; and   a control unit configured to control operation of each processing unit, wherein   one of the processing units is a pulper,   the pulper has a stirring chamber, a stirring device to rotationally drive a stirring blade in the stirring chamber, and a water supply unit to supply dilution water to the stirring chamber,   the control unit operates the stirring device sequentially in a defiberization operating mode, a transition operating mode, and a dilution operating mode, and   disaggregates, in the defiberization operating mode, the waste paper in a predetermined amount of disaggregating water stored in the stirring chamber to generate a waste paper pulp slurry by rotating the stirring blade at the number of revolutions for defiberization,   stirs, in the transition operating mode, the waste paper pulp slurry by rotating the stirring blade at the number of revolutions for defiberization while supplying the dilution water from the water supply unit to the waste paper pulp slurry in the stirring chamber, and   stirs, in the dilution operating mode, the waste paper pulp slurry by rotating the stirring blade at the number of revolutions for stirring, in which the number of revolutions for stirring is lower than the number of revolutions for defiberization, while supplying the dilution water from the water supply unit to the waste paper pulp slurry in the stirring chamber.   
     
     
         2 . The waste paper recycling apparatus according to  claim 1 , further comprising a concentration detection unit configured to detect a concentration of the waste paper pulp slurry in the stirring chamber, wherein
 the control unit switches the operation mode with reference to the concentration of the waste paper pulp slurry detected by the concentration detection unit to switch the transition operating mode to the dilution operating mode at a transition termination concentration in transition operation, and   the transition termination concentration is set lower than a defiberization termination concentration in the defiberization operating mode and set higher than a dilution termination concentration in dilution operation in the dilution operating mode.   
     
     
         3 . The waste paper recycling apparatus according to  claim 2 , wherein
 one of the processing units is a waste paper inlet to charge the stirring chamber with the waste paper,   the waste paper inlet has a weight sensor to measure a waste paper charge amount to be put into the stirring chamber,   the water supply unit has a flow sensor to measure an amount of water supplied to the stirring chamber, and   the concentration detection unit calculates the concentration of the waste paper pulp slurry from a weight sensor measurement and a flow sensor measurement.   
     
     
         4 . The waste paper recycling apparatus according to  claim 1 , wherein
 one of the processing units is a waste paper inlet to charge the stirring chamber with the waste paper,   the waste paper inlet charges the stirring chamber with the waste paper a plurality of times,   the control unit operates the stirring device in a defiberization preparation operation mode during waste paper charging operation of the waste paper inlet, and   the control unit roughly tears, in the defiberization preparation operation mode, the charged waste paper by rotating the stirring blade at the number of revolutions for rough tearing and spreading, lower than the number of revolutions for stirring.   
     
     
         5 . The waste paper recycling apparatus according to  claim 2 , wherein
 one of the processing units is a waste paper inlet to charge the stirring chamber with the waste paper,   the waste paper inlet charges the stirring chamber with the waste paper a plurality of times,   the control unit operates the stirring device in a defiberization preparation operation mode during waste paper charging operation of the waste paper inlet, and   the control unit roughly tears, in the defiberization preparation operation mode, the charged waste paper by rotating the stirring blade at the number of revolutions for rough tearing and spreading, lower than the number of revolutions for stirring.   
     
     
         6 . The waste paper recycling apparatus according to  claim 3 , wherein
 one of the processing units is a waste paper inlet to charge the stirring chamber with the waste paper,   the waste paper inlet charges the stirring chamber with the waste paper a plurality of times,   the control unit operates the stirring device in a defiberization preparation operation mode during waste paper charging operation of the waste paper inlet, and   the control unit roughly tears, in the defiberization preparation operation mode, the charged waste paper by rotating the stirring blade at the number of revolutions for rough tearing and spreading, lower than the number of revolutions for stirring.