Mandrel-wound flocculant-containing fiber filtration tubes

Abstract

Fiber filtration tubes containing flocculant are produced by winding a preformed mat of natural fibers about a mandrel. The tubes may be joined end to end to produce products of significant length, and are highly suitable in removing even very fine sediment during use in erosion control.

1 . A fiber filtration tube suitable for use in erosion control, having a cross-section and a length, said fiber filtration tube comprising 
 an inner portion comprising a mandrel or a void left by removal of a mandrel, said inner portion located at or proximate the center of the cross-section of said fiber filtration tube;    an outer portion spirally wrapped around said inner portion, said outer portion comprising, prior to wrapping, a mat of natural fibers; and a flocculant.    
   
   
       2 . The fiber filtration tube of  claim 1 , wherein said inner portion is a void.  
   
   
       3 . The fiber filtration tube of  claim 1 , wherein said inner portion is a mandrel comprising biodegradable material.  
   
   
       4 . The fiber filtration tube of  claim 1 , wherein said mat of natural fibers comprises natural fibers and a consolidating binder.  
   
   
       5 . The fiber filtration tube of  claim 1 , wherein said consolidating binder comprises thermoplastic fibers.  
   
   
       6 . The fiber filtration tube of  claim 1 , wherein said natural fibers comprise wood fibers.  
   
   
       7 . The fiber filtration tube of  claim 1 , wherein said flocculant comprises a soluble polyacrylamide homopolymer or copolymer.  
   
   
       8 . The fiber filtration tube of  claim 1 , further comprising a sheath of netting surrounding said outer portion.  
   
   
       9 . The fiber filtration tube of  claim 8 , wherein said netting is a polymer netting.  
   
   
       10 . The fiber filtration tube of  claim 9 , wherein said polymer netting comprises a biodegradable polymer.  
   
   
       11 . The fiber filtration tube of  claim 1 , wherein said mat of natural fibers further comprise bicomponent thermoplastic fibers, as a consolidating binder.  
   
   
       12 . The fiber filtration tube of  claim 1 , comprising 
 an inner portion comprising a non-removable mandrel or a void left by removal of a removable mandrel, wherein said non-removable mandrel, when present, comprises natural fibers;    an outer portion comprising a substantially planar mat of natural fibers consolidated by mechanical means or by incorporation of a binder to provide a handleable web;    a flocculant, said flocculant applied to the surface of the web prior to spirally winding the web around the mandrel, or incorporated within the web;    a structure for preventing the outer portion of the fiber filtration tube from unwinding.    
   
   
       13 . The fiber filtration tube of  claim 12 , wherein said planar mat comprises natural fibers and thermoplastic fibers as a binder.  
   
   
       14 . The fiber filtration tube of  claim 12 , wherein said inner portion comprises a void, and said outer portion comprises a mat of 80% by weight or more wood fibers, and thermoplastic fibers, said thermoplastic fibers present in an amount of less than 20 weight percent.  
   
   
       15 . The fiber filtration tube of  claim 14 , wherein said thermoplastic fibers are bicomponent fibers.  
   
   
       16 . The fiber filtration tube of  claim 12 , wherein said structure comprises a sheath of netting.  
   
   
       17 . A fiber filtration tube, comprising a plurality of fiber filtration tubes of  claim 1 , adhesively bonded end-to-end and encompassed in a sheath of netting.  
   
   
       18 . A fiber filtration tube, comprising a plurality of fiber filtration tubes of  claim 12 , adhesively bonded end-to-end and encompassed in a sheath of netting.  
   
   
       19 . A process for the preparation of a fiber filtration tube, comprising 
 a) providing a mandrel;    b) winding around said mandrel a plurality of layers of a mat comprising natural fibers to form a fiber filtration tube;    c) supplying a flocculant in or on the mat;    d) securing the fiber filtration tube from unwinding; and    e) optionally, removing the mandrel from the fiber filtration tube.    
   
   
       20 . The process of  claim 19 , wherein the mat comprises a blend of wood fibers and thermoplastic fibers.  
   
   
       21 . The process of  claim 19 , further comprising inserting the fiber filtration tube into a sheath of netting.  
   
   
       22 . The process of  claim 19 , further comprising 
 f) inserting a fiber filtration tube into a forming tube;    g) preparing a subsequent fiber filtration tube;    h) applying an adhesive to at least one of the fiber filtration tube inserted within the forming tool or to the subsequent fiber filtration tube;    i) inserting the subsequent fiber filtration tube into the forming tube such that the ends of the fiber filtration tube within the forming tube and the subsequent fiber filtration tube inserted into the forming tube become adhesively bonded end-to-end.    
   
   
       23 . A fiber filtration tube which is effective in decreasing soil runoff from earthen surfaces, comprising 
 an inner portion comprising a mandrel or a void left by removal of a mandrel, said inner portion located at or proximate the center of the cross-section of said fiber filtration tube;    an outer portion spirally wrapped around said inner portion, said outer portion comprising, prior to wrapping, a mat comprising natural fibers;    one or more securing devices for securing the filtration tube from unrolling, but not preventing ingress and egress of water.    
   
   
       24 . The fiber filtration tube of  claim 23 , wherein said mandrel is a triangular mandrel.  
   
   
       25 . The fiber filtration tube of  claim 23 , wherein at least one securing device comprises a polymer netting sheath substantially surrounding the filtration tube.  
   
   
       26 . A process for minimizing soil runoff due on a sloped surface, comprising installing a filtration tube of  claim 1  across at least a portion of the surface to impede the flow of water and sediment.  
   
   
       27 . A process for minimizing soil runoff on a sloped surface, comprising installing a filtration tube comprising a roll of a natural fiber mat product containing a major amount of natural fibers across at least a portion of the surface to impede the flow of water and sediment.