US 4,904,440 A · Apparatus for and methods of airlaying fibrous webs having discrete particles therein

Abstract

Apparatus for and methods of forming airlaid fibrous webs having a multiplicity of layers and/or discrete particles of absorbent gelling material dispersed through at least a portion of the web. The apparatus is of the type which includes a laydown drum having a foraminous forming element, a primary vacuum chamber, and a dusting layer vacuum chamber; a primary hood; and a dusting layer hood. The dusting layer of fibers formed on the laydown drum acts to block the passage of particles or fibers entrained in a first fiber stream which is airlaid over the dusting layer so as to minimize equipment plugging problems and the loss of particles or fibers through the foraminous forming element. The primary vacuum chamber of the laydown drum preferably spans the primary hood and a portion of the dusting layer hood so that the dusting layer is not sheared off, damaged, or destroyed as the laydown drum rotates to the position where the first fiber stream is deposited over the dusting layer.

Claims61

Dependent claims

An apparatus for forming airlaid fibrous webs having a multiplicity of layers or discrete particles dispersed through at least a portion of the web, said apparatus comprising:

airlaying means having a foraminous forming element for forming an airlaid fibrous web;
dusting layer deposition means positioned adjacent a first portion of the periphery of said airlaying means for directing a dusting layer stream of air-entrained fibers to said foraminous forming element of said airlaying means and for depositing the fibers on said foraminous forming element so as to form a dusting layer, said dusting layer deposition means having a first sector and a second sector;
primary deposition means positioned adjacent a second portion of the periphery of said airlaying means for directing a primary stream of air-entrained fibers to said foraminous forming element of said airlaying means and for depositing the fibers onto said foraminous forming element over the dusting layer so as to form a primary layer over a dusting layer;
dusting layer vacuum means for drawing fiber-depleted air through siad foraminous forming element, said dusting layer vacuum means being positioned subjacent said first sector of said dusting layer deposition means;
and
primary vacuum means for drawing fiber-depleted air through said foraminous forming element, said primary vacuum means being positioned subjacent both said primary deposition means and said second sector of said dusting layer deposition means so as to prevent the dusting layer formed on said foraminous forming element from being damaged or destroyed.

3 more elements

A method for forming airlaid fibrous webs having a multiplicity of layers or discret particles dispersed through at least a portion of the web, said method comprising the steps of:

a. forming a dusting layer on a foraminous forming element of an airlaying drum;
b. transferring said dusting layer to the influence of a pressure differential maintained by a primary vacuum chamber positioned subjacent the foraminous forming element while said dusting layer is still positioned under a dusting layer sector of the periphery of the airlaying drum;
c. passing said dusting layer from the dusting layer sector to a primary sector of the periphery of the airlaying drum while said dusting layer is under the inflence of the pressure differential maintained by said primary vacuum chamber;
and
d. forming a primary layer on said foraminous forming element over said dusting layer so as to form an airlaid fibrous web having a primary layer over a dusting layer.

2 more elements

A method for forming airlaid fibrous webs having a multiplicity of layers or discrete particles dispersed through at least a portion of the web, said method comprising the steps of:

a. providing a dusting layer stream of air-entrained fibers;
b. directing said dusting layer stream of air-entrained fibers toward a dusting layer sector of the periphery of an airlaying drum to a foraminous forming element positioned on the airlaying drum;
c. depositing said dusting layer stream of air-entrained fibers onto the foraminous forming element;
d. drawing the entrainment air through the foraminous forming element by a pressure differential maintained by a dusting layer vacuum chamber and a primary vacuum chamber positioned subjacent the foraminous forming element;
e. collecting the fibers on the foraminous forming element to form a dusting layer;
f. transferring said dusting layer to the influence of the pressure differential maintained by the primary vacuum chamber while said dusting layer is still positioned in the dusting layer sector of the airlaying drum;
g. passing said dusting layer under the dusting layer sector to a primary sector of the periphery of the airlaying drum while the dusting layer is under the influence of the pressure differential maintained by the primary vacuum chamber;
h. providing a primary stream of air-entrained fibers;
i. directing said primary stream of air-entrained fibers toward the primary sector of the periphery of the airlaying drum to the foraminous forming element;
j. depositing said primary stream of air-entrained fibers on the foraminous forming element over said dusting layer;
k. drawing the entrainment air through the foraminous forming element by the pressure differential maintained by the primary vacuum chamber positioned subjacent the foraminous forming element;
and
l. collecting the fibers on the foraminous forming element over said dusting layer to form a primary layer over said dusting layer so as to form an airlaid fibrous web having a primary layer over a dusting layer.

10 more elements

An apparatus for forming airlaid fibrous webs having a multiplicity of components each formed from a portion of a column of fibers, said apparatus comprising:

a splitting means for splitting a column of fibers into a multiplicity of fiber streams and for entraining each of the fiber streams in air so as to provide a multiplicity of streams of air-entrained fibers;
a laydown drum having a foraminous forming element disposed about the periphery of said laydown drum;
a dusting layer deposition chute connected to said splitting means for directing a dusting layer stream of air-entrained fibers from said splitting means to said foraminous forming element;
a dusting layer hood connected to said dusting layer deposition chute and positioned adjacent a dusting layer portion of the periphery of said laydown drum;
a primary deposition chute connected to said splitting means for directing a primary stream of air-entrained fibers from said splitting means to said foraminous forming element;
and
a primary hood connected to said primary deposition chute and positioned adjacent a primary portion of the periphery of said laydown drum.

4 more elements

An apparatus for forming airlaid fibrous webs having a multiplicity of components each formed from a portion of a column of fibers, said apparatus comprising:

a splitter chute comprising:
a base;
four side walls extending from said base defined by a first side wall, a second side wall opposed to said first side wall, and an opposed pair of lateral side walls;
a curvilinear top wall positioned on said side walls and having a plurality of ports disposed in and along the surface of said top wall and comprising
a first port, and
a dusting layer port,
wherein a column of fibers is directed along the surface of said top wall to said ports;
a first conduit duct for directing a column of air past said first port so as to cause a portion of the column of fibers to split off and be drawn into said first conduit duct to form a primary fiber stream, and for entraining the primary fiber stream in the air to direct the primary fiber stream downstream, said first conduit duct having an inlet and a discharge outlet, said first conduit duct being in communication with said first port;
and
a dusting layer conduit duct for directing a column of air past said dusting layer port so as to cause a portion of the column of fibers to split off and be drawn into said dusting layer conduit duct to form a dusting layer fiber stream, and for entraining the dusting layer fiber stream in the air to direct the dusting layer fiber stream downstream, said dusting layer conduit duct having an inlet and a discharge outlet, said dusting layer conduit duct being in communication with said dusting layer port;
a laydown drum having a foraminous forming element disposed about the periphery of said laydown drum;
a dusting layer deposition chute connected to said splitter chute for directing a dusting layer stream of air-entrained fibers from said splitter chute to said foraminous forming element;
a dusting layer hood connected to said dusting layer deposition chute and positioned adjacent a dusting layer portion of the periphery of said laydown drum;
a primary deposition chute connected to said splitter chute for directing a primary stream of air-entrained fibers from said splitter chute to said foraminous forming element;
and
a primary hood connected to said primary deposition chute and positioned adjacent a primary portion of the periphery of said laydown drum.

13 more elements

An apparatus for forming airlaid fibrous webs having a multiplicity of components each formed from a portion of a column of fibers, said apparatus comprising:

a curvilinear splitting member having a plurality of ports disposed in and along a surface of said splitting member and comprising a first port and a dusting layer port;
a first conduit duct that is in communication with said first port of said splitting member, said first conduit duct directing a column of air past said first port to cause a portion of the column of fibers to split off and be drawn into said first conduit duct to form a primary fiber stream and entraining the primary fiber stream in the air to direct the primary fiber stream downstream;
and a dusting layer conduit duct that is in communication with said dusting layer port of said splitting member, said dusting layer conduit duct directing a column of air past said dusting layer port to cause a portion of the column of fibers to split off and be drawn into said dusting layer conduit duct to form a dusting layer fiber stream and entraining the dusting layer fiber stream in the air to direct the dusting layer fiber stream downstream;
a laydown drum having a foraminous forming element disposed about the periphery of said laydown drum;
a dusting layer deposition chute connected to said dusting layer conduit duct for directing a dusting layer stream of air-entrained fibers from said dusting layer conduit duct to said foraminous forming element;
a dusting layer hood connected to said dusting layer deposition chute and positioned adjacent a dusting layer portion of the periphery of said laydown drum;
a primary deposition chute connected to said first conduit duct for directing a primary stream of air-entrained fibers from said first conduit duct to said foraminous forming element;
and
a primary hood connected to said primary deposition chute and positioned adjacent a primary portion of the periphery of said laydown drum.

6 more elements

An apparatus for forming fibrous webs having a multiplicity of components each formed from a portion of a column of fibers, said apparatus comprising:

a curvilinear splitting member having a plurality of ports disposed in and along a surface of said splitting member and comprising a first port, a second port, and a dusting layer port;
a first conduit duct that is in communication with said first port of said splitting member, said first conduit duct directing a column of air past said first port to cause a portion of the column of fibers to split off and be drawn into said first conduit duct to form a first fiber stream and for entraining the first fiber stream in the air to direct the first fiber stream downstream;
a second conduit duct that is in communication with said second port of said splitting member, said second conduit duct directing a column of air past said second port to cause a portion of the column of fibers to split off and be drawn into said second conduit duct to form a second fiber stream and for entraining the second fiber stream in the air to direct the second fiber stream downstream;
a dusting layer conduit duct that is in communication with said dusting layer port of said splitting member, said dusting layer conduit duct directing a column of air past said dusting layer port to cause a portion of the column of fibers to split off and be drawn into said dusting layer conduit duct to form a dusting layer fiber stream and for entraining the dusting layer fiber stream in the air to direct the dusting layer fiber stream downstream;
a laydown drum having a foraminous forming element disposed about the periphery of said laydown drum, a primary vacuum chamber, and a dusting layer vacuum chamber;
a dusting layer deposition chute connected to said dusting layer conduit duct for directing the dusting layer stream of air-entrained fibers from said dusting layer conduit duct to said foraminous forming element;
a dusting layer hood having a first sector and a second sector positioned downstream of said first sector, said dusting layer hood being connected to said dusting layer deposition chute and positioned adjacent a dusting layer portion of the periphery of said laydown drum;
a primary deposition chute connected to said first conduit duct and said second conduit duct for merging the first stream of air-entrained fibers and the second stream of air-entrained fibers and for directing the resultant primary stream of air-entrained fibers from said first conduit duct and said second conduit duct to said foraminous forming element;
absorbent gelling material injection means connected to said primary deposition chute for mixing discrete particles of absorbent gelling material with the primary stream of air-entrained fibers;
and
a primary hood connected to said primary deposition chute and positioned adjacent a primary portion of the periphery of said laydown drum, said primary hood being positioned downstream of said dusting layer hood and intersecting with said dusting layer hood at at least a point of intersection to allow for the equalization of pressures in the portions of said dusting layer hood and said primary hood adjacent said point of intersection;
wherein said primary vacuum chamber is positioned subjacent both said primary hood and said second sector of said dusting layer hood, and wherein said dusting layer vacuum chamber is positioned subjacent said first sector of said dusting layer hood.

9 more elements

Dependencies are inferred from the claim text.

Apparatus for and methods of airlaying fibrous webs having discrete particles therein

Life of this patent

Apparatus for and methods of airlaying fibrous webs having discrete particles therein

Life of this patent

Abstract

Claims61