Method and system for agglomerating chopped fiber strand and product

Abstract

A new system and method for making agglomerates of chopped glass fiber strand segments is disclosed as are the agglomerates produced. The agglomerates, made by feeding wet chopped fiber strand segments into a wave chamber having a vibrating curved surface that produces a wave-like flow pattern in the segments and agglomerates, have a substantially higher bulk density and greatly improved flow characteristics than conventional chopped strand reinforcements. The wet agglomerates are usually dried in any conventional dryer.

1 . A system for making agglomerated fiber strand segment reinforcing products comprising one or more fiberizers for converting molten material to a plurality of fibers, one or more applicators for applying an aqueous chemical sizing to the fibers, one or more guides for gathering the plurality of fibers into one or more strands, a chopper for separating the wet strands into segments, and an agglomerator for combining two or more of said segments into agglomerates and a dryer for drying said agglomerates, the improvement comprising that the agglomerator comprises a generally horizontal, non-rotating wave chamber having an elongated, curved, vibrating working surface for contact with the wet chopped strand segments, a working surface that is concave in cross section on a plane perpendicular with the length of the wave chamber.  
     
     
         2 . The system described in  claim 1  wherein the curved working surface is an arc of a circle containing and contains at least about 60 degrees with at least a majority of the at least about 60 degrees being on one side of an imaginary vertical line running through the lowest point on the working surface.  
     
     
         3 . The system described in  claim 2  wherein all of the at least about 45 degrees is on one side of said vertical line.  
     
     
         4 . The system of  claim 1  wherein said wave chamber is supported entirely with springs.  
     
     
         5 . The system of  claim 2  wherein said wave chamber is supported entirely with springs.  
     
     
         6 . The system of  claim 1  wherein the vibration of the working surface is provided with one or more vibrators, the vibrators being separated from said wave chamber by springs whereby the vibration is transmitted through the springs.  
     
     
         7 . The system of  claim 2  wherein the vibration of the working surface is provided with one or more vibrators, the vibrators being separated from said wave chamber by springs whereby the vibration is transmitted through the springs.  
     
     
         8 . The system of  claim 5  wherein the vibration of the working surface is provided with one or more vibrators, the vibrators being separated from said wave chamber by springs whereby the vibration is transmitted through the springs.  
     
     
         9 . The system of  claim 6  wherein the vibrators are mounted on a member, which member supports said springs separating said wave chamber from said vibrators, said member also being supported on springs mounted on a base.  
     
     
         10 . The system of  claim 7  wherein the vibrators are mounted on a member, which member supports said springs separating said wave chamber from said vibrators, said member also being supported on springs mounted on a base.  
     
     
         11 . The system of  claim 8  wherein the vibrators are mounted on a member, which member supports said springs separating said wave chamber from said vibrators, said member also being supported on springs mounted on a base.  
     
     
         12 . A system for making agglomerated fiber strand segment reinforcing products comprising one or more fiberizers for converting molten material to a plurality of fibers, one or more applicators for applying an aqueous chemical sizing to the fibers, one or more guides for gathering the plurality of fibers into one or more strands, a chopper for separating the wet strands into segments, and an agglomerator for combining two or more of said segments into agglomerates and a dryer for drying said agglomerates, the improvement comprising that the agglomerator comprises a generally horizontal, non-rotating wave chamber having an elongated, curved, vibrating working surface for contact with the wet chopped strand segments, a working surface that is concave in cross section on a plane perpendicular with the length of the wave chamber and wherein said working surface is vibrated by one or more vibrators that are separated from said working surface by a plurality of springs, said vibrators being separated from a base by one or more springs, said working surface.  
     
     
         13 . The system of  claim 12  wherein said working surface is textured.  
     
     
         14 . The system of  claim 12  wherein said working surface has one or more radii and comprises at least 60 degrees on one side of an imaginary vertical line passing through the lowest part of the working surface.  
     
     
         15 . The system of  claim 14  wherein said working surface is textured.  
     
     
         16 . A method of agglomerating wet chopped fiber strand segments in an agglomerator, the improvement comprising using as the agglomerator a generally horizontal, non-rotating wave chamber comprising an elongated vibrating curved working surface having one or more radii, said working surface having at least about 45 degrees on one side of an imaginary vertical centerline passing through the lowest point of said working surface.  
     
     
         17 . The method of  claim 16  wherein said segments have a moisture content of at least about 10 wt. percent based on the dry weight of said segments and below about 15 wt. percent and wherein said wave chamber is supported by springs.  
     
     
         18 . The method of  claim 17  wherein the wet chopped strand has a moisture content of about 12.5 to about 13.5 wt. percent as chopped and as fed into the agglomerator and wherein said agglomerates are dried to produce agglomerated chopped fiber strand reinforcements for reinforcing plastics.  
     
     
         19 . The method of  claim 16  wherein the moisture content of said segments is in the range of about 10 to about 15 wt. percent on based on dry weight of said segments and wherein said wave chamber is supported by springs.  
     
     
         20 . The method of  claim 19  wherein said agglomerates are dried to produce agglomerated chopped fiber strand reinforcements for reinforcing plastics.  
     
     
         21 . The method of  claim 20  wherein said segments are about {fraction (1/8)} inch to about {fraction (1/4)} inch long, wherein said moisture content is in the range of about 12 wt. percent to about 13.5 wt. percent and wherein the diameters of the majority of said reinforcements are in the range of about {fraction (1/16)} inch to about {fraction (3/16)} inch.  
     
     
         22 . The method of  claim 18  wherein the vibration of said working surface is supplied by one or more vibrators separated from said wave chamber by a plurality of springs.  
     
     
         23 . The method of  claim 22  wherein said one or more vibrators are separated from a base by a plurality of springs.  
     
     
         24 . The method of  claim 16  wherein said working surface declines from a feed end to an exit end at an angle in the range of about 1 degree to about 5 degrees.  
     
     
         25 . The method of  claim 17  wherein said working surface is textured.  
     
     
         26 . The method of  claim 18  wherein said working surface is textured.  
     
     
         27 . The method of  claim 21  wherein said working surface is textured.  
     
     
         28 . The method of  claim 23  wherein said working surface is textured.  
     
     
         29 . The method of  claim 24  wherein said working surface is textured.  
     
     
         30 . A method of making dry agglomerates from wet chopped fiber strand segments comprising an aqueous sizing on the surfaces of the fibers by passing said segments through an agglomerator to form agglomerates followed by drying said agglomerates to form agglomerates for reinforcing various materials including plastics, the improvement comprising using as the agglomerator a generally horizontal, non-rotating wave chamber comprising a vibrating, elongated, curved working surface having one or more radii with said working surface having at least about 60 degrees on one side of an imaginary vertical line passing through the lowest part of said working surface, said wave chamber being supported by a plurality of springs, a working surface being concave in cross section in a plane passing perpendicular to the length of said working surface, the moisture content of the just chopped segments and the same segments entering the agglomerator is in the range of about 12 to about 15 wt. percent.  
     
     
         31 . The method of  claim 30  wherein said working surface has one radius and is either a circle or a portion of a circle in cross section perpendicular to the length of said working surface.  
     
     
         32 . The method of  claim 30  wherein said working surface is textured.  
     
     
         33 . The method of  claim 31  wherein said working surface is textured.  
     
     
         34 . Agglomerates of fiber strand segments produced by the method of  claim 16 .  
     
     
         35 . Agglomerates of fiber strand segments produced by the method of  claim 30 .  
     
     
         36 . Agglomerates of fiber strand segments produced by the method of  claim 33.