Dewatering fabric in a paper machine

Abstract

A dewatering fabric for use in a paper machine, the dewatering fabric including a woven permeable fabric and a polymeric layer having openings therethrough, the polymeric layer connected to the permeable fabric.

1 . A dewatering fabric for use in a paper machine, the dewatering fabric comprising: 
 a woven permeable fabric; and    a polymeric layer having openings therethrough, said polymeric layer connected to said permeable fabric.    
   
   
       2 . The dewatering fabric of  claim 1 , further comprising at least one batt layer needled to said permeable fabric and said polymeric layer, thereby connecting said permeable fabric and said polymeric layer.  
   
   
       3 . The dewatering fabric of  claim 1 , wherein said openings accommodate an airflow substantially straight therethrough without an other airflow perpendicular to said airflow.  
   
   
       4 . The dewatering fabric of  claim 1 , wherein said polymeric layer is a flexible polyurethane.  
   
   
       5 . The dewatering fabric of  claim 1 , wherein said polymeric layer is a grid of polymeric material, said grid having a plurality of machine direction runs and a plurality of cross direction runs.  
   
   
       6 . The dewatering fabric of  claim 5 , further comprising a plurality of yarns combined with said grid of polymeric material, thereby forming a composite layer, at least one of said yarns internal to each of a corresponding one of said plurality of machine direction runs.  
   
   
       7 . The dewatering fabric of  claim 6 , further comprising at least one batt layer needled to said permeable fabric and said composite layer, thereby connecting said permeable fabric and said composite layer.  
   
   
       8 . The dewatering fabric of  claim 1 , wherein said polymeric layer is connected to said permeable fabric by at least one of laminating, melting, re-melting and an adhesive.  
   
   
       9 . The dewatering fabric of  claim 1 , wherein said polymeric layer includes a plurality of yarns within said polymeric layer.  
   
   
       10 . The dewatering fabric of  claim 1 , wherein said permeable fabric and said polymeric layer together have a thickness, said thickness less than 1.50 mm.  
   
   
       11 . The dewatering fabric of  claim 10 , wherein said thickness is less than 1.25 mm.  
   
   
       12 . The dewatering fabric of  claim 11 , wherein said thickness is less than 1.00 mm.  
   
   
       13 . The dewatering fabric of  claim 1 , wherein said permeable fabric and said polymeric layer together have an air permeability, said air permeability being less than 130 cfm.  
   
   
       14 . The dewatering fabric of  claim 13 , wherein said air permeability is less than 65 cfm.  
   
   
       15 . The dewatering fabric of  claim 14 , wherein said air permeability is less than 35 cfm.  
   
   
       16 . The dewatering fabric of  claim 1 , wherein said woven permeable fabric includes a plurality of weft yarns and a plurality of warp yarns.  
   
   
       17 . The dewatering fabric of  claim 16 , wherein said weft yarns lie in a machine direction, said weft yarns having a diameter of between approximately 0.40 mm and 0.10 mm.  
   
   
       18 . The dewatering fabric of  claim 17 , wherein said diameter is approximately 0.20 mm.  
   
   
       19 . The dewatering fabric of  claim 16 , wherein said warp yarn has a diameter of between approximately 0.30 mm and 0.10 mm.  
   
   
       20 . The dewatering fabric of  claim 19 , wherein said diameter is approximately 0.20 mm.  
   
   
       21 . The dewatering fabric of  claim 1 , further comprising a hydrophobic layer having pores therethrough.  
   
   
       22 . The dewatering fabric of  claim 21 , wherein said pores have a mean pore diameter of less than 140 microns.  
   
   
       23 . The dewatering fabric of  claim 22 , wherein said pores have a mean pore diameter of less than 100 microns.  
   
   
       24 . The dewatering fabric of  claim 23 , wherein said pores have a mean pore diameter of less than 60 microns.  
   
   
       25 . A machine for the manufacture of a fibrous web, comprising: 
 at least one roll; and    a dewatering fabric in at least partial contact with said at least one roll, said dewatering fabric including:    a woven permeable fabric; and    a polymeric layer having openings therethrough, said polymeric layer connected to said permeable fabric.    
   
   
       26 . A permeable membrane for use in a paper machine, the permeable membrane comprising: 
 at least one batt fiber layer; and    a permeable fabric, said at least one batt fiber layer and said permeable fabric being needle punched with straight through drainage channels.    
   
   
       27 . The membrane of  claim 26 , further comprising at least one anti-rewet layer attached to at least one of said permeable fabric and said at least one batt fiber.  
   
   
       28 . The membrane of  claim 27 , wherein said anti-rewet layer is an elastomeric membrane.  
   
   
       29 . The membrane of  claim 28 , wherein said elastomeric membrane is less than approximately 1.05 mm thick.  
   
   
       30 . The membrane of  claim 25 , wherein said at least one anti-rewet layer is attached by melting said anfi-rewet layer.  
   
   
       31 . The membrane of  claim 26 , wherein said permeable fabric includes machine direction yarns and cross direction yarns, said machine direction yarns at least double in number per square meter than said cross direction yarns.  
   
   
       32 . The membrane of  claim 31 , wherein said machine direction yarns are larger in diameter than said cross direction yarns.  
   
   
       33 . The membrane of  claim 26 , further comprising an anti-rewet layer having a first side and a second side, said first side attached to said permeable fabric, said at least one batt fiber layer includes an other batt fiber layer connected to said second side.  
   
   
       34 . The membrane of  claim 33 , wherein said anti-rewet layer includes pores therethrough.  
   
   
       35 . The membrane of  claim 26 , wherein said pores have a mean pore diameter in the range of approximately 5 microns to approximately 75 microns.  
   
   
       36 . The membrane of  claim 26 , further comprising at least one hydrophobic layer applied to an outer surface of the membrane.  
   
   
       37 . The membrane of  claim 26 , wherein said at least one batt fiber layer includes a plurality of fibers ranging from 0.5 d-tex to 22 d-tex.  
   
   
       38 . The membrane of  claim 26 , wherein said permeable fabric and said at least one batt layer together have a thickness, said thickness less than 1.50 mm.  
   
   
       39 . The membrane of  claim 38 , wherein said thickness is less than 1.25 mm.  
   
   
       40 . The membrane of  claim 39 , wherein said thickness is less than 1.00 mm.  
   
   
       41 . The membrane of  claim 26 , wherein said permeable fabric and said at least one batt layer together have an air permeability, said air permeability being less than 130 cfm.  
   
   
       42 . The membrane of  claim 41 , wherein said air permeability is less than 100 cfm.  
   
   
       43 . The membrane of  claim 26 , wherein said permeable fabric includes a plurality of weft yarns and a plurality of warp yarns.  
   
   
       44 . The membrane of  claim 43 , wherein said weft yarn has a diameter of between approximately 0.40 mm and 0.10 mm.  
   
   
       45 . The membrane of  claim 44 , wherein said diameter is approximately 0.20 mm.  
   
   
       46 . The membrane of  claim 43 , wherein said warp yarn has a diameter of between approximately 0.30 mm and 0.10 mm.  
   
   
       47 . The membrane of  claim 46 , wherein said diameter is approximately 0.20 mm.  
   
   
       48 . A machine for the manufacture of a fibrous web, comprising: 
 at least one roll; and    a permeable membrane in at least partial contact with said at least one roll, said permeable membrane including: 
 at least one batt fiber layer; and  
 a permeable fabric, said at least one batt fiber layer and said permeable fabric being needle punched with straight through drainage channels.  
   
   
   
       49 . A method of making a paper machine dewatering fabric, comprising the steps of: 
 providing a permeable fabric; and    applying an elastomeric grid to a side of said permeable fabric.    
   
   
       50 . The method of  claim 49 , further comprising the step of needling at least one batt fiber layer to said permeable fabric and said elastomeric grid.  
   
   
       51 . The method of  claim 49 , wherein said applying step includes one of the steps of adhering and melting said elastomeric grid to said permeable fabric.  
   
   
       52 . The method of  claim 49 , wherein said permeable fabric includes a plurality of machine direction yarns, said grid not being aligned with said machine direction yarns.  
   
   
       53 . The method of  claim 49 , wherein said permeable fabric includes machine direction yarns, said grid being generally aligned with said machine direction yarns.  
   
   
       54 . The method of  claim 53 , wherein said grid includes a plurality of machine direction runs having at least one yarn in a corresponding one of said plurality of machine direction runs.  
   
   
       55 . A dewatering fabric for use in a papermaking machine, the dewatering fabric comprising: 
 a woven permeable fabric having a thickness of less than 1.50 mm, said woven permeable fabric having an air permeability of less than 130 cfm.    
   
   
       56 . The fabric of  claim 55 , wherein said air permeability is less than 100 cfm.  
   
   
       57 . The fabric of  claim 55 , wherein said thickness is less than 1.25 mm.  
   
   
       58 . The fabric of  claim 57 , wherein said thickness is less than 1.00 mm.  
   
   
       59 . The fabric of  claim 55 , wherein said woven permeable fabric has pores therethrough.  
   
   
       60 . The fabric of  claim 59 , wherein said pores have a mean diameter of from approximately 5 to approximately 75 microns.  
   
   
       61 . The fabric of  claim 60 , wherein said pores have a mean diameter of from approximately 25 to approximately 75 microns.  
   
   
       62 . The fabric of  claim 61 , wherein said pores have a mean diameter of from approximately 35 to approximately 75 microns.  
   
   
       63 . The fabric of  claim 59 , wherein said pores have a mean diameter of one of equal to and less than approximately 140 microns.  
   
   
       64 . The fabric of  claim 63 , wherein said pores have a mean diameter of one of equal to and less than approximately 100 microns.  
   
   
       65 . The fabric of  claim 64 , wherein said pores have a mean diameter of one of equal to and less than approximately 60 microns.  
   
   
       66 . The fabric of  claim 59 , wherein said pores have a mean diameter of approximately 15 microns.  
   
   
       67 . A method of using a dewatering fabric in a papermaking machine, comprising the steps of: 
 transporting the dewatering fabric through an advanced dewatering system, said advanced dewatering system including a vacuum roll in at least partial contact with the dewatering fabric over a portion of a surface of said vacuum roll defining a vacuum zone;    passing air through the dewatering fabric and a fibrous web; and    applying pressure to the dewatering fabric, the dewatering fabric including a woven permeable fabric having a thickness of less than approximately 1.50 mm, said woven permeable fabric having an air permeability of less than 130 cfm.    
   
   
       68 . A method of using a dewatering fabric in a low press/no press papermaking machine, comprising the steps of: 
 passing air through the dewatering fabric and a fibrous web; and    applying pressure to the dewatering fabric, the dewatering fabric including a woven permeable fabric having a thickness of less than approximately 1.50 mm, said woven permeable fabric having an air permeability of less than 130 cfm.