Dual Zone Wireless Pulp Washer

Abstract

A wireless dual zone pulp washer with rotating concentric filters for creating centrifugal force against feedstock in order to expel liquid contained in the feedstock before further processing of the stock. A secondary filter surrounds the primary filter to capture viable pulp fibers expelled from the feedstock by the dewatering process.

1 . A pulp thickening apparatus for removing fluid from pulp stock in a dewatering system comprising: 
 a feed manifold for supplying the apparatus with pulp stock;    a primary cylindrical filter for accepting said pulp stock from said feed manifold and for creating centrifugal force against said pulp stock to expel liquid therethrough, said primary cylinder filter being devoid of any associated wire member in contact therewith; and    first removal means for removing said pulp stock from a surface of said primary cylindrical filter.    
   
   
       2 . The pulp thickening apparatus according to  claim 1  further comprising a secondary cylindrical filter surrounding said primary cylindrical filter for collecting pulp fibers that flow through said primary filter, said secondary cylindrical filter being devoid of any associated wire member in contact therewith.  
   
   
       3 . The pulp thickening apparatus according to  claim 2  further comprising a second removal means for removing said pulp stock from a surface of said secondary cylindrical filter.  
   
   
       4 . The pulp thickening apparatus according to  claim 2  wherein said secondary cylindrical filter has smaller openings than said primary cylindrical filter.  
   
   
       5 . The pulp thickening apparatus according to  claim 2  wherein said primary and secondary cylindrical filters are both rotatable around a common axis and create centrifugal force which expels fluid from said pulp stock.  
   
   
       6 . The pulp thickening apparatus according to  claim 5  further comprising an outlet for discharging fluid from said apparatus.  
   
   
       7 . The pulp thickening apparatus as recited in  claim 1  further comprising a compression roller adjacent said primary cylinder filter and between said feed manifold and said first removal means.  
   
   
       8 . The pulp thickening apparatus as recited in  claim 1  further comprising a water wash nozzle adjacent said primary cylinder filter and between said feed manifold and said first removal means.  
   
   
       9 . The pulp thickening apparatus as recited in  claim 1  wherein said feed manifold and first removal means define a first pair of feed manifold and removal means, said dewatering system further comprising another pair of feed manifold and removal means in operative association with said primary cylindrical filter.  
   
   
       10 . A method of dewatering pulp stock comprising the steps of: 
 a. delivering pulp stock to a wireless rotating primary filter;    b. applying centrifugal force to said pulp stock;    c. expelling fluid, small pulp fibers, and contaminants from said pulp stock through said rotating primary filter;    d. collecting primary accepts including fibers and other material on said rotating primary filter; and    e. removing said primary accepts from said primary filter.    
   
   
       11 . The method according to  claim 10  further comprising the step of receiving said small pulp fibers and contaminants on a rotating wireless secondary filter.  
   
   
       12 . A wireless pulp thickening system comprising: 
 two cylindrical filters for expelling water and contaminates from pulp stock by centrifugal force with a feed-line for supplying said filters with pulp stock.    
   
   
       13 . Method for thickening pulp stock comprising: 
 a. providing a first rotatable cylinder carrying a first filter medium;    b. providing a second rotatable cylinder carrying a second filter medium;    c. feeding a pulp stock suspension into said first rotatable cylinder;    d. subjecting said pulp stock suspension to centrifugal force in said first rotatable cylinder to expel liquid, small fibers, and contaminants through said first filter medium and collect primary accepts from said first filter medium;    e. forwarding said expelled liquid, small fibers, and contaminants into said second rotatable cylinder; and    f. subjecting said expelled liquid, small fibers, and contaminants to centrifugal force in said second rotatable cylinder to expel liquid through said second filter medium and collect secondary accepts from said secondary filter medium.    
   
   
       14 . Method as recited in  claim 13 , further comprising providing first vane means around the circumference of said first rotatable cylinder to regulate flow of said pulp suspension through said first filter medium.  
   
   
       15 . Method as recited in  claim 13 , further comprising providing second vane means around the circumference of said second rotatable cylinder to regulate flow of said pulp suspension through said second filter medium.  
   
   
       16 . Method as recited in  claim 13 , wherein said second filter medium has a finer mesh than said first filter medium.  
   
   
       17 . Method as recited in  claim 13 , wherein said step (c) comprises feeding a stratified feed of said pulp suspension on an inside surface of said first rotatable cylinder.  
   
   
       18 . Method as recited in  claim 17  wherein said stratified feed comprises a plural layer arrangement of said pulp suspension having a first layer of short fibers and heavy fines laid contiguous to said inside surface.  
   
   
       19 . Method as recited in  claim 18  wherein said plural layer arrangement comprises a top layer of long fibers and light fines superposed on said first layer and remote from said inside surface.  
   
   
       20 . Method as recited in  claim 13 , wherein said second rotatable cylinder is concentrically disposed with and surrounds said first rotatable cylinder.  
   
   
       21 . Apparatus for thickening a pulp stock suspension comprising: 
 a. first rotatable cylinder carrying a first filter medium;    b. a second rotatable cylinder carrying a second filter medium;    c. means for feeding a pulp stock suspension into said first rotatable cylinder;    d. means for rotating said first and second rotatable cylinder for creating centrifugal force therein whereby pulp stock suspension in said first rotatable cylinder will impinge upon said first filter medium with primary accepts forming on one said of said first filter medium and with liquid and other material from said pulp stock suspension being expelled through said first filter medium and into contact with said second filter medium, whereby secondary accepts will gather on said second filter medium;    e. means for collecting accepts material gathered on said first filter medium;    f. means for collecting accepts material formed on said second filter medium; and    g. means for transporting materials passing through said first and second filter media away from said apparatus.    
   
   
       22 . Apparatus as recited in  claim 21 , wherein said second filter medium is of a finer mesh than said first filter medium.  
   
   
       23 . Apparatus as recited in  claim 21 , wherein said second rotatable cylinder is concentric with and surrounds said first rotatable cylinder.  
   
   
       24 . Apparatus as recited in  claim 21 , wherein said first rotatable cylinder comprises a first set of adjustable vane means around the circumference of said first rotatable cylinder for selectively adjusting gaps between individual ones of said vanes to regulate flow of said pulp stock suspension through said first rotatable cylinder.  
   
   
       25 . Apparatus as recited in  claim 24 , wherein said second rotatable cylinder comprises a second set of adjustable vane means around the circumference of said second rotatable cylinder for selectively adjusting gaps between individual ones of said second set of vanes to regulate flow of said pulp suspension through said second filter medium.  
   
   
       26 . Headbox feeder adapted for feeding pulp suspension to a filter medium surface, said feeder apparatus comprising a cyclonic separator in the form of an enclosed truncated cone having a central axis, a base end, and a closed apex end, an inlet opening at said base end and laterally offset from said axis to impart a rotational vector to said pulp suspension upon entry into said cone, a feed slot manifold connected to said cone between said base end and said closed apex end providing an exit for said pulp suspension.  
   
   
       27 . Headbox feeder apparatus as recited in  claim 26  wherein said feed slot manifold comprises a housing portion extending away from truncated cone.  
   
   
       28 . Headbox feed apparatus as recited in  claim 27  wherein said feed slot manifold is laterally offset from said axis.  
   
   
       29 . Headbox feed apparatus as recited in  claim 27  wherein said housing has a first leg extending away from said truncated cone and a radiused section terminating in a slot.  
   
   
       30 . Method of feeding a pulp suspension to a filter surface comprising: 
 a. providing a separator;    b. admitting said pulp suspension to said separator;    c. forming a stratified arrangement of said suspension in said separator, including a first layer of heavier fines, short fibers, and contaminants and a second layer of longer fibers and lighter fines; and    d. feeding said stratified arrangement to said filter surface.    
   
   
       31 . Method as described in  claim 30  wherein said step (d) comprises placing said first layer contiguous with said filter surface with said second layer superposed over said first layer.  
   
   
       32 . Method as described in  claim 30  wherein said step (d) comprises placing said second layer of longer fibers and lighter fines contiguous with said filter surface and said first layer superposed over said second layer.  
   
   
       33 . Method of feeding a pulp suspension to a filter surface as recited in  claim 30  further comprising forming an intermediate layer of fines and fibers, said intermediate layer located intermediate said first and second layers.  
   
   
       34 . Method of feeding a pulp suspension to a filter surface as recited in  claim 28  wherein said separator is a headbox feeder apparatus.