Process and arrangement for replacing intra-fiber liquid in fibers with a replacement liquid

Abstract

A process and apparatus for replacing intra-fiber liquid in fibers by a replacement liquid, includes compressing the fiber cake to express a substantial quantity of intra-fiber liquid to the space between the fibers; forcibly supplying replacement liquid to the fiber cake during the compression thereby replacing the intra-fiber liquid from the space between the fibers and letting the fibers expand while supplying additional replacement liquid. The invention gets rid of or significantly reduces the content of contaminating material in not only the areas between the fibers in a fiber cake but also in the fiber wall pores and the lumen and replaces this liquid by a replacement liquid.

1 - 18 . (canceled)  
   
   
       19 . Process for replacing liquid inside the fiber walls with a replacement liquid adapted to modify the properties of the fibers, comprising the following steps; compressing a fiber cake to such a degree that a substantial quantity of the liquid inside the fiber walls is expressed into the space between the fibers and partially out of the fiber cake, forcibly supplying the replacement liquid to the fiber cake during the compression into the space between the fibers and thus displacing the original liquid inside the fiber walls from the space between the fibers and letting the fibers expand while supplying additional replacement liquid which is thus further absorbed by the expanding fibers.  
   
   
       20 . Process according to  claim 19 , wherein the replacement liquid contains chemical treating agent.  
   
   
       21 . Process according to  claim 19 , wherein the replacement liquid is acid or basic for fast acid or base treatment of the pulp fibers.  
   
   
       22 . Process according to  claim 19 , wherein the replacement liquid contains bleaching chemical.  
   
   
       23 . Process according to  claim 19 , wherein the replacement liquid contains delignifying agent.  
   
   
       24 . Process according to  claim 19 , wherein the replacement liquid contains process catalyst.  
   
   
       25 . Process according to  claim 19 , wherein the replacement liquid contains chelating agent.  
   
   
       26 . Process according to  claim 19 , wherein the replacement liquid contains fluorescent tracer.  
   
   
       27 . Process according to  claim 19 , wherein the replacement liquid contains metal ions.  
   
   
       28 . Process according to  claim 19 , wherein the replacement liquid contains cationic or anionic polymer.  
   
   
       29 . Process according to  claim 19 , wherein the replacement liquid contains dyeing substance.  
   
   
       30 . Process according to  claim 19 , wherein the replacement liquid contains inorganic substance.  
   
   
       31 . Arrangement for replacing liquid inside fiber walls with a replacement liquid comprising a device ( 1 , 4 , 4   a , 5 , 5   a ) for compressing a fiber cake in such a degree that a substantial quantity of liquid inside the fiber walls is expressed to the space between the fibers and partially out of the fiber cake, a first device ( 6 , 8 , 9 ) for forcibly supplying the replacement liquid to the fiber cake during the compression and a second device ( 7 , 14 ) for supplying the additional replacement liquid immediately after the device for compression arranged in an expansion area where the fibers are allowed to expand after the compression while absorbing the replacement liquid.  
   
   
       32 . Arrangement according to  claim 31 , wherein the device for compressing the fiber cake ( 1 , 4 , 5 ) comprises a rotating compression roll ( 4 ) and a press ( 5 ) arranged opposite the compression roll ( 4 ) with a press nip in which the fibers are fed and the device ( 6 ) for forcibly supplying the replacement liquid to the fibers during the compression is a compressible fabric ( 6 ) with liquid permeability only in the thickness direction arranged as a moving closed loop in at least partly contact with the compression roll ( 4 ) where at least a part of the closed loop in the press nip is in contact with the compressed fibers and a device ( 7 , 14 ) for supplying replacement liquid to the compressible fabric ( 6 ).  
   
   
       33 . Arrangement according to  claim 31 , wherein the device for compressing the fiber cake ( 1 , 4 , 5 ) comprises a rotating compression roll ( 4   a ) and a press ( 5   a ) arranged opposite the compression roll ( 4   a ) with a press nip in which the fibers are fed and the device ( 8 , 9 ) for forcibly supplying the replacement liquid to the fibers during the compression comprises radial holes ( 8 ) in the compression roll ( 4   a ) and a pressurized replacement liquid container ( 9 ) arranged in the compression area to supply pressurized replacement liquid through the holes ( 8 ) from the inside of the compression roll ( 4   a ) into the fibers in the compression area.  
   
   
       34 . Arrangement according to  claim 32 , wherein the second device ( 7 ) supplying the replacement liquid is a trough with its bottom opening ( 13 ) just after the press nip.  
   
   
       35 . Arrangement according to  claim 32 , wherein the second device ( 14 ) supplying the replacement liquid is a replacement liquid reservoir defined by a part of the interior of the closed loop of the compressible fabric ( 6 ) and a part of the envelope surface of the compression roll ( 4 )  
   
   
       36 . Arrangement according to  claim 35 , wherein the replacement liquid reservoir ( 14 ) is arranged just before the closed loop goes into contact with the compression roll ( 4 ).  
   
   
       37 . Arrangement according to  claim 35 , wherein the replacement liquid reservoir is arranged after the closed loop leaves contact with the compression roll.  
   
   
       38 . System characterized in that it comprises more than one arrangement according to  claim 31 , in series.  
   
   
       39 . Arrangement according to  claim 31 , wherein the replacement liquid is cleaner liquid.  
   
   
       40 . Arrangement according to  claim 31 , wherein the replacement liquid contains chemical treating agent.  
   
   
       41 . Arrangement according to  claim 31 , wherein the replacement liquid is acid or basic for fast acid or base treatment of the pulp fibers.  
   
   
       42 . Arrangement according to  claim 31 , wherein the replacement liquid contains bleaching chemical.  
   
   
       43 . Arrangement according to  claim 31 , wherein the replacement liquid contains delignifying agent.  
   
   
       44 . Arrangement according to  claim 31 , wherein the replacement liquid contains process catalyst.  
   
   
       45 . Arrangement according to  claim 31 , wherein the replacement liquid contains chelating agent.  
   
   
       46 . Arrangement according to  claim 31 , wherein the replacement liquid contains fluorescent tracer.  
   
   
       47 . Arrangement according to  claim 31 , wherein the replacement liquid contains metal ions.  
   
   
       48 . Arrangement according to  claim 31 , wherein the replacement liquid contains cationic or anionic polymer.  
   
   
       49 . Arrangement according to  claim 31 , wherein the replacement liquid contains dyeing substance.  
   
   
       50 . Arrangement according to  claim 31 , wherein the replacement liquid contains inorganic substance.