CA1315942C

CA1315942C - Apparatus for and methods of providing a multiplicity of streams of air-entrained fibers

Info

Publication number: CA1315942C
Application number: CA000537855A
Authority: CA
Inventors: John Joseph Angstadt
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 1986-05-28
Filing date: 1987-05-25
Publication date: 1993-04-13
Anticipated expiration: 2010-04-13
Also published as: PT84955B; AU582525B2; DK269187D0; JPS6354162A; EG18464A; GB2191793A; PH23713A; MA20985A1; AU7343587A; IL82510A0; FI872383A; FI95053B; US4765780A; IE60036B1; DE3777645D1; FI872383A0; NZ220459A; DK269187A; EP0297180A1; FI95053C

Abstract

APPARATUS FOR AND METHODS OF PROVIDING
A MULTIPLICITY OF STREAMS OF AIR-ENTRAINED FIBERS

ABSTRACT

Apparatus for and methods of providing a multiplicity of streams of air-entrained fibers. The apparatus is of the type which includes a splitting member having multiple ports disposed along the splitting member; a first conduit means such as a conduit duct for directing a column of air past a first port, the first conduit means being in communication with the first port;
and a second conduit means such as a conduit duct for directing a column of air past a second port, the second conduit means being in communication with the second port.

The method preferably comprises the steps of:

a. directing a column of fibers along a splitting member having a first port and a second port;
b. directing a column of air through a first conduit means and past the first port so as to draw a portion of the fiber column into the first conduit means to form a first fiber stream;
c. entraining the first fiber stream in the air;
d. directing the first fiber stream downstream;
e. directing a column of air through a second conduit means and past a second port so as to draw a portion of the column of fibers into the second conduit means to form a second fiber stream;
f. entraining the second fiber stream in the air; and g. directing the second fiber stream downstream.

Description

~31~2 APPAF~ATUS FOR AND METHODS OF PROVIDING
A MULTIPLICITY OF STREAMS OF AIR-E~ITRAINED FIBERS

FIELD OF THE INVENTION

This invention reiates to ,oroviding a multiplicity of streams of air-entrained fibers. More particuiarly, the inventlon relates to splltting a column of fibers into a multiplicity of fiber streams and entraining each fiber stream in air, ciumping of the fibers in :~ : the apparatus being minimized.

BACI'~GROUND OF THE INVENTION
: ;
Absorbent articles such as disposable diapers, incontinent pads and catamenial napkins generally include an absorbent core that has a multiplicity of components so as to improve the absorption and retention characteristics of the absorbent core.
lS Recent advances in the field of a~sorbent cores have deveioped a : . re!atlvely new class of: materials :known as superabsorbent polymers or absorbent gelling ~rnaterials (AGM's! which can be : incorporated alon~ with ~ absorbent fibrous materials to form improved absorbent cores. Multi-component absorbent cores 20 : wherein ~at teast one component consists solel:y of hydrophillic fibers and at least one : component consists of a substantially uniform combination of hydrophillic fibers ans~ particular amounts of discrete particles of absorbent gelling materiais, have been :.~

2 ~31~9~

found to be especially efficient and effective in absorbing and containing bodily fluids.

Several difficulties are encountered in manufacturing absorbent cores; having a multiplicity of components especially wherein at least one of the components contains discrete particles of an absorbent gellin~3 materiai. YVhile such absorbent cores can be manufactured by two or more separate and complete core~making apparatus, the costs of providing such a system is prohibitive. Accordingly, it would be advantageous to provide a single apparatus for forming fibrous webs having a multiplicity of components .

In addition, because absorbent gelling materials are generally significantly more expensive than readily available hydrophillic fibe~ materials ~e.g. cellulose fibers), it would be advantageous to reduce the quantity of absorbent gelling materials in the core by not spreading absorbent gelling materials throughout the entire core but by targeting them in specific areas or components of the absorbent core. However, wi~h conventional airlaying apparatus, it is difficult to limit absorbent gelling materials to only one component. Thus, it would be advantageous to provide an apparatus and method for forming an absorbent core having a multiplicity of components wherein only one of the components contains a small amount of AGM in the critical areas ra~her than thr~oughout the entire absorbent core.

One solution to providing an apparatus and method for forming such an absorbent core is to split a column of fibers formed by a disintegrator into individual streams of fibers which can be individually directed to different airlaying apparatus or different portions of the same airlaying apparatus. However, a ma)or disadvantage of attempting to split a column of fibers is that ~the fibers tend to clump and accumulate around ~he splitting mechanism. In particular, when a fiber column is split by mechanical means such as a doctor's edge or dividing plane or diverting vane, the clum ping phenomenon is especially acute.

~, ~31~9~2 Thus, it would be advantageous to provide an apparatus for and method of splitting a column of fibers into a multiplicity of fiber streams while reducing the amount of fiber clumping.
Accordingly, it is an object of an aspect of the present invention to provide an apparatus for and method of splitting a fiber column into a multiplicity of fiber streams.
It i9 also an object of an aspect of the presPnt invention to minimize fiber clumping during the splitting of the fiber column.
It is an object of an aspect of the present invention to provide an apparatus for providing multiple, independent streams of air-entrained fibers.

SUMMARY OF THE INVENTION

Various aspects of this invention are as follows:

An apparatus for providing a multiplicity of streams of air-entrained fibers by splitting a column of fibers into multiple fiber streams and by independently entraining each of the fi~ers streams in air, 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 second port circumferentially spaced downstream and completely axially offset from said first port, wherein a column of fibers is directed along said surface of said splitting member to said ports;

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 o~ the column of B

,.. . . ... . ..

~ 3a 1315942 fibers to split off and be drawn into said first conduit duct to form a first fiber stream and entraining the first fiber stream in the air to direct the first fiber stream downstream; and a second conduit duct that is in communication ~"ith 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 entraining the second fiber stream in the air to direct the second fiber stream downstream.

A splitter chute apparatus for providing a multiplicity of streams of air-entrained fibers by splitting a column of fibers into multiple fiber streams and by independently entraining each of the fiber streams in air, said splitter chute apparatus comprising:

a base;

four side walls extending from said base defined by a first side wall, a second side wall opposed to : said ~irst side wall, and an opposed pair of lateral side walls;

. a curvilinear top wall positioned on said side w~lls and having a plurality of ports disposed in : : ~and along the surface of said top wall and : comprising a first port, and ~a second port at least partially axially offset from said first port, :~

; .
., ", . . . .. .

'~
~ 3b ~L31~942 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 ko 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 f.irst 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 second conduit duct for directing a column of air past said second port so as 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, said second conduit duct having an inlet and a discharge outlet, said second conduit duct being in communication with said second port.

A method for splitting a column of fibers into a multiplicity of streams of air-entrained fibers, the method comprising the steps of:

providing a column of fibers;

directing said column o~ fibers along the surface of a curvilinear splitting mPmber having a plurality of ports comprising a first port and a ~second port;

imparting angular velocity and momentum to said column of fibers;

.~, ,. ~

~ 3c ~3~59~2 directing a first column of air through a first conduit duct past the first port so as to create a pressure differential adjacent the first port;

releasing a first portion of said column of fibers away from its angular path of travel;

drawing said first portion of said column of fibers through the first port into the ~irst conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent the irst port so as to form a first fiber stream;

entraining said first fiber stream in the first column of air;

: directing the first stream of air-entrained fibers downstream;

directing a second column of air through a second conduit duct past the second port so as to create a pressure dlfferential adjacent the second port;

releasing a second portion of said column of fibers away from its angular path of travel;

drawing said second portion of said column of fibers through the second port into the second conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent the second port so as to form a second 25 . ~ fiber s~ream;

entraining said second fiber straam in the second - column of air; and :
~';
~, ,.,,, .- ~ .

3d directing the second stream of air-entrained f ibers downstream.

In a particularly preferred embodiment, the present invention comprises apparatus for and method of providing a multiplicity of streams of air-entrained fibers. The apparatus is of the type which includes a splitting member having multiple ports disposed along the splitting member; a first conduit means such as a conduit duct for directin~ a high velocity column o~ air past a first port, the first conduit means being in communication with the first port; and a second conduit means such as a conduit duct for directing a high velocity column of air past a second port, the second conduit means being in communication with the second port.
By maintaining a relatively high velocity column of air moving past the ports of the splitting member, a pressure differential is created between the pressure in the fiber column and the air column, such that fibers that are directed along the port tend to split-off and be drawn into the conduit duct. This splitting process is enhanced by the fact that the fibers are preferably directed along a curvilinear path such that the angular velocity and momentum of the fibers tends to pull the fibers away .
~., ~''' .

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4 ~31~2 from their path of travel ~oward the conduit duct. Besause the fibers streams are split-off via air an~l fiber momentum, there is less clumping because the fibers do not impinge on any surfaces.
Thus, the apparatus minimizes fiber clumping as well as providing an efficient and effective means for providing a multiplicity of independent streams of air-entrained fibers.

The method preferably comprises the steps of:

a. directing a column of fibers along a splitting member having a first port and a second port:

b. directing a column of air through a first conduit means and past the first port so as to draw a portion of the fiber column into the first conduit means to form a first fiber stream;

c. entraining the first fiber stream in the air;

~15 d. directing the first fiber stream downstream;

e. directing a column of air through a second conduit means and past a second port so as to draw a portion of the column of fibers into the second conduit means to form a second fiber stream;
.
f. entraining the second fiber stream in the air; and 9. directing the second fiber stream downstream.

BRIEF DESCRIPTION OF THE DRAWINGS
:: :
While the specification conciudes with claims particutarly pointing out and distinctly claiming the present invention, it is believed the present invention will be better understood from the following description in conjunction with the ascompanying drawings in which:

--~\ s ~3~9~
Figure 1 is a partially out-away side views of a preferred apparatus of the present invention Figure 2 is a perspective view of the splitter ehlJte apparatus of the present invention;

S Figure 3 is 3 bottom view of the splitter chute apparatus of the present invention;

Figure 4 is a cross-sectional view taken along section line 4-4 of Figure 2;

Figure 5 is a cross-sectional view taken along section line 5-5 of Figure 2;

Figure 6 is a cross-sectional view taken along section line 6-6 of Figure 2;

Figure 7 is an enlarged cross-sectional illustration of a transition zone of a splitter chute apparatus;

Figure 8 is a schematic illustration of the first deposition chute of the present invention;

Figure 9 is an enlarged cross-sectional view of the first airlaying means of the present invention.

Figure 10 is a cut-away view of a preferred disposable absorbent article such as a diaper having a dual-layer absorbent core formed by the apparatus and methods of the present invention .

Figure 11 is an enlarged cross-sectional view of the insert core component of the absorbent core of the diaper shown in Figure 10. .

DETAILED DESCPdPTlON OF THE INVENTI{)N
.

131~2 While the present invention will be described in detail in the context of providing airlaid fibrous webs for use as absorbent cores in absorbent articles such as disposable diapers, the present invention is in no way limited to such an application. The presPnt invention may be employed with equal facility to provide airlaid fibrous webs for later incorporation into a number of articles, including incontinent briefs, sanitary napkins, bandages and the like.
Figure 10 shows a particularly preferred embodiment of a disposable diaper having an abssrbent core formed by the apparatus and methods of the present invention.
The disposable diaper lO00 comprises a topsheet 1002, a liquid impervious backsheet 1004, and an absorbent core 1006 disposed between the topsheet 1002 and the backsheet 1004. A preferred construction of such a disposable diaper is described in U~S. Patent 3,860,003, issued January 14, 1975 to Renneth B. Buell, which patent is herein incorporated by reference.
The absorbent core 1006 preferably comprises two or more distinct core components. The absorbent core comprises an insert core component 1008 (first web component) and a shaped core component 1010 (second web component). This preferred absorbent core is described in more detail in Canadian Patent ~pplication Serial Number 509,085 Dale T. Weisman, Dawn I. Houghton, and Paul E. Gellert.
The shaped core component 1010 serves to quickly collect and temporarily hold and distribute discharged body fluid. Thus, the wicking properties of the materials vr fibers in the shaped core component 1010 are of primary importance. Therefore, the shaped core component 1010 consists essentially o~ an hourglass shaped web of hydrophyllic fiber material. While many type~ of ibers are suitable ~or use in the shaped core component 1010, preferred types o~ fibers ara cellulose fibers, in particular, wood pulp fibars. While the shaped core component ,";

~ 7 131~94~
1010 i5 preferably free of particles of an absorbent gelling material, the shaped core component 1010 may alternath~eiy contain small amounts of particles of an absorbent gelling material so as to enhance its fluid acquisition properties. Other materials 5 in combination with the fibers may also be incorporated into the core component such as synthetiç fibers.

The insert core component 1008 absorbs discharged bsdy fluids from the shaped core component 1010 and retains such fluids. As shown in Figures 10 and 11, the insert core component 1008 consists essentialiy of a thin dustirlg layer 1012 of hydrophyllic fiber material overlayed by a primary layer 1014 of a uniform combination of hydrophy!lic fiber material and particular amounts of discrete particles 1016 of substantiaily water-insoluble, fluid absorbing, absorbent gelling materiais. The hydrophyllic lS fibers in the insert core componen~ 1008 are preferably of the same type as those herein described for use in the shaped core component 1010. There are several suitable absorbent gelling materials which can be used in the insert core component, such as silica gels or organic compounds such as crosslinked polymers.
Particularly preferred absorbent gelling materials are hydrolyzed acrylonitrile grafted starch, acrylic acid grafted starch, polyacrylates and isobutylene maleic anhydride copolymers, or mixtures thereof.

While the dusting layer 1012 of the absorbent core 1006 is preferably a relative!y thin layer of hydrophillic fiber materials, it should be understood that the term "dusting layer", used herein to denote a certain layer of the fibrous web or as a prefix to identi* certain elements which form or are used to form the dusting l~yer, should no~ be limited to such a thin layer, but inc~ludes embodiments wherein such a laysr may be any thickness.
For ~example, the dusting layer is preferably about 1.0 inch to about 1.5 inch (about 25 mm to about 38 mm) thick with about 1. 25 inches (about 31 . 75 mm) being especially preferred, although thicker or thinner layers are contemplated.

::

8 ~ 942 Figure 1 discloses a particularly preferred embodiment of the apparatus for forming airlaid fibrous webs having multiplicity of components such as the absorbent core 1006 of the disposable diaper 1000 that is shown in Figures 10 and 11, In the 5 embodiment illustrated in Figure 1, the apparatus 20 is shown to comprise a pair of counter-rotating metering infeed rolls 22 for directing a roll 24 of drylap material into engagernent with a disintegrator 26, the disintegrator 26 having a rotary disintegrating element 28 partially enclosed by a housing 30; a 10 splitting means or apparatus such as a splitter chute 32 ~or providing multiplicity of streams of air-entrained fibers; a first airlaying means such as a drum-type airlaying apparatus 34 for forming a first web component a first deposition means suçh as a first deposition chute 36 and hood 38 ~or directing a first stream 15 of air-entrained fibers to the first airla~ing means and for depositing the fibers on th~ first airlaying means; an absorbent gelling material injection apparatus 40 or means for mixing discrete particles of an absorbent gelling material with the stream of air-entrained fibers that is directed through the first 20 deposition chute 36: a dusting layer deposition means such as a dusting layer deposition chute 42 and hood 44 for directing a dusting layer stream of air-entrained fibers to the first airlaying means and depositing the fibers on the first airlaying means a second airlaying means such as a second drum-type airlaying 25 apparatus 46 for forming a ~econd web component; a second deposition means such as a second deposition chute 48 and hood 50 for directing a second stream of air-entrained fibers to the : second airlaying means and for depositing the fibers onto the second airlaying means: and a uniting means such as a uniting 30 rol I apparatus 52 for uniting the first and second web - components, In order to simplify the disclosure, several elements or means which can readily be supplied by those skilled in the art have b~en omitted from the dra~vings, Such elements include structural members, bearings, power transmission units, 35 controlling units and the like. Additionally, a first stream 54 of air-entrained fibers is shown in Figure 1 to be moving through the first deposition chute 36; a dusting iayer stream 56 of ~ g air-entrained fibers is shown to be moving 32 through the dusting layer deposition chute 42; a second stream 58 of air-entrained fibers is shown to be moving through the second deposition chute 48; an endless stream of insert core components 1008 (first web components) is shown moving on the belt 60 of a first take-away conveyor 62; and an endless stream of shaped core components 1010 (second web components) is shown moving on the belt 64 o~ a second take-away conveyor 66.

A preferred embodiment of a disintegrator 26 is shown in Figure 1 to comprise a rotary disintegrating element 28 paxtially enclosed in a housing 30. ~
similar-type disintegrator is shown in U.S. Patent 3,863,296, issued on February 4, 1~75 to Kenneth B.
Buell. However, as used herein, the term "disintegrator" i5 not intended to limit the present invention to apparatus of the type illustrated in the above patent, but includes apparatus such as hammermills, fiberizers, picker rolls, lickerin rolls or any other apparatus which separates a roll or mat of fibrous material into its individual fibers.

As used herein, a fibrous or drylap material or sheet describes any type of fibrous sheet material capable of disintegration into individual fibers. For example, the fibrous material can include fibers of rayon, polyester, cotton or the like, with cellulosic fibers being especially preferred.

The disintegrator 25 preferably comprises a rotary disin~egrating element 28~comprising a plurality of rotors 68 and a housing 30 having a generally cylindrical bore 70. A shaft 72 is journaled in the closed ends of the housing 30 such that one end of the shaft 72 extends outside the housing 30 to pe~mit , .
~' 9a 131~9~2 coupling the shaft in a conventional manner to a motive power source such as an electric motor (not shown). The motor continuously drives the shaft 72 in the direction as shown. The rotors 68 are keyed to the sha~t 72 in juxtaposed r~lation, each being provided with a plurality of teeth 74 extending outwardly such that their tips are , ~,, , 131 ~942 adapted to serve as impacting elements. As used herein, "rotor"
refers to thin rotored discs. With the above arrangement, successive teeth 74 impact the end of the infeeding sheet 24 as the rotors are turned. The rotors 68, when keyed into place and molded together, form an axial rotary cylindrical disintegrating element 28 rotatable about its cylindrical axis. This configuration is preferred since it permits the favorable internal distribution of stresses set up during operation of the disintegrator 26.

The housing 30 partially encloses the disintegrating element 1n 28 and defines a flow channel 78 for a column of fibers between the disintegrating element and the housing. The flow channel 78 i5 sized to give from about one thirty second to about one-fourth inch (about 0.79 mm to about 6.3~ mm) clearance between the blade tips of the disintegrating element 28 and the housing 30 so as to direct the column of fibers from the inn~r end of the housing toward the splitter ehute 32. The housing 30 has a cylindrical bore 70 to partially enclose the disintegrating element 28 and an inlet portion 80 which is slotted to provide an inlet opening having an inner end. ~YYhile the housing 30 may alternatively be comprised of additional elements, such are not preferred in the present invention). The inlet opening 80 is disposed so as to receive the fibrous sheet 24 and guide it to the inner end, which defines a sheet support element, whereat an edge of the fibrous sheet 24 is disintegrated.

With the above arrangement, successive teeth 74 impact the end of the infeeding drylap sheet 24 as the rotors 68 are turned to separate the fibers of the fibrou~ sheet 21~ into individual fibers. After separation of the fibers of the fibrous sheet into the individual fibers, a column of fibers i5 formed across the axial width of the housing 30. As used herein, "a column of fibers" denotes a pattern or system of fibers disposed across the axial width of the housing. The rotation of the disintegrating eiement 28 imparts an inherent velocity to the fibers across the axial width of the housing 30, whereupon a continuous column of fibers is directed around the fiow channel 78 toward the splitter chute 32.

As shown in Figure 1, the splitter chute 32 is preferably joined to the housing 30 of the disintegrator 26. The term 5 "joined" includes embodiments wherein the splitter chute 32 is a separate element directly or indirectly connected to or within the housing 30 ti.e. integral~ or embodiments wherein the splitter chute 32 is the same element as the housing 30 so that the splitter chute 32 is a continuous and undivided element of the 10 housing 30 (i.e., unitary~. While the splitter chute 32 may be an independent apparatus from the disintegrator 26, or the splitter chute 32 may be unitary with the housing 30 of the disintegrator 26, such embodiments are not preferred. The splitter chute 32 is preferabiy an integral member that is joined into the housing 30 15 of the disintegrator 26.

Figure 2 shows a particularly preferred embodiment of an apparatus (splitting means or splitter chute 32) for forming a multiplicity of streams of air-entrained fibers by splitting a column of fibers into a multiplicity of fiber streams and independently entraining each of the fiber streams in air. As shown in Figure 2, the apparatus comprises a splitting member 200 having a number of ports disposed in and along its surface.
As shown, the ports are designated a first port 202, a second port 204, a third port 206, and a dusting layer port 208. The apparatus also comprises multipie independent conduit means, ~such as conduit ducts, for directing high velocity columns of air past the ports disposed along the stripping member 200. The conduit ducts are designated in Figure 2 according to which port with which the conduit duct is in communicatîon, so as to define a first conduit duct 210, a second conduit duct 212, a third conduit duct 214 and a dusting layer conduit duct 216.
: :
The splitter chute 32 shown in Figure 2 is a preferred embodiment of the apparatus of the present invention. The splitter chute is shown in Figure 2 to additionally comprise a base 12 1 3 ~ %

218, four side walls 220,222, 224 and 226, respectively, and a top wall 228 which defines the splitting member 200, The base 218 preferably extends beyond the lateral side walls 222 and 226 to define flanges 230 having bores 232 so that the splitter chute 32 may be bolted or otherwise secur ed in any conventional manner to the housing 30 vf the disintegrator 26. Figure 3 shows a preferred embodiment of the base 218, the base 218 being shown to accommodate the discharge outlets of each of the conduit ducts. As shown in Figure 3, the discharge outlets are designated a first discharge outiet 234, a second discharge outlet 236, a third discharge outlet 238 and a dusting layer discharge outiet 2400 The splitting member 200 provides a means for splitting the colurnn of fibers into mul~iple fiber streams. The splitting member 200 directs the column of fibers to the ports where portions of the column of fibers are split-off into individual fiber streams. The term "splitting member" is used herein to describe a number of different structures having varying configurations and shapes such as ducts, pipes, sheets or combinations of 2b sheets of material, a number of plates in combination, or a number of different elements in combination. The splitting member 200 is shown in Figure 2 as a curvilinear surface defined by the top wall 228 of the splitter chute 32. However, alternative preferred split~ing members include a duct having ports disposed therein or, for example, if the splitter chute 32 is unitary with the housing 30 of the disintegrator 26, the splittin~
memDer ~00 may comprise a combination of a portion of the disintegrating element 28, the housing 30, and the surface of the top wall 228 of the splitter chu~e 32, together defining a flow channel 78 through which the column of fibers may be directed.

While the splitting member 200 may have a number of configurations, the surface in which the ports are located or disposed pretferably has a curvilinear profile. A curvilinear profile provides angular displacement and velocity components to the fibers to assist in separating and in drawing off the fibers :

13 1~15~4~

into the individual conduit ducts without the presence of fiber catching mechanical edges or walls such that fiber clumping is minimized. While flat or rectilinear splitting members are contemplated by the present invention, they do not provide this S angular displacement advantage as will be described later. In addition, when the splitter chute 32 is joined to the housing 30, a curvilinear splitting member accommodates the shape of the disintegrating element ~8. While the curvilinear profile of the splitting member is preferably circular in nature, a number of different cur~ilinear profiles would be equally preferred such as hyperbolic, parabolic or ellipsoid profiles.

The splitting member 200 may be positioned anywhere relative t~ where the column of fibers are disçharged by the disintegrating element 28. For example, the splitting member 200 of the splitter chute 32 may be positioned relatively for downstream from the disintegrator 26. However, this configuration is not preferred because the column of fibers tends to lose its momentum and are subject to width biasing into fiber wads the farther from the disintegrating element 28 the splitting member 200 is positioned. Thus it has been found that in order to have as clean and accurate a split as possible (a split which provides consistent basis weight fiber streams and minimizes fiber clumping~, the splitting rnember 200 shoulci be positioned as closely as possible to the di~integrating element ~8, preferably adjacent to it so that the column of fibers is drawn away from and off of the disintegrating element as it is split into the fiber streams .

As shown in Figure 2, the splitting member 200 is provided with a number of ports. The ports put the columns of air that are directed through the conduit ducts in communication with the portior) of the column of fibers that is directed along the splitting member 200 so that portions of the fiber column may be split-off and drawn into the conduit duct to form a distinct fiber stream.
Thus the ports provide an opening for the intake of a stream of fibers into the conduit ducts. While the ports may take a number 14 1 31~9~2 of shapes and configurations, a preferred configuration of each of the ports is a rectangular-shaped opening having an upstream edge and a downstream or doctor's edge. (These edges are shown and described more particularly in Figure 4, 5 and 6).

In order to effectively and efficiently split-off the fibers, at least two ports must be at least partiaily laterally spaced from each other. As used herein, the term "laterally spaced" is used to denote that a portion of a port is offset to one sTde of and out of alignment with at least a portion of another port such that a line that is perpendicular to the lateral dimension would not intersect both of the ports. ( Lateral being dcfined as the dimension across the width of the splitting member. 1 Thus, a partially laterally spaced port denotes that a portion of the first port is disposed to one side of and out of alTgnment with a portion of the second port. The ports may alternatively and - preferably bç completely axially offset. In addition, each of the ports may be either longitudinally aligned or spaced downstream or upstream from each other. The term "longitudinally spaced"
being used herein to denote that a port is disposed upstream or downstream from another. t Longitudinal being defined as the dimension along the length of the splitting member. ~ A preferred configuration provides that each successive port be laterally spaced and longitudinally spaced from each successive port. This configuration providing the most efficient split of the fiber 2 5 col umn .

As shown in Figure 2, the first port 2û2 preferably is disposed acljacent a lateral side wall 232 of the splitter chute 32, an outermost portion of the column o~ fibers thereby being split-off by the first port 2Q2. The second port 204 is preferably longitudinally spaced downstream and laterally spaced from the first port 202 so as to split-off a second or central width of the column of fibers. The third port 206 is preferably longitudinally aligned with the first port 202 but is laterally spaced from both the first and second ports so as to strip off a third width of fibers from the column of fibers. The dusting layer port 208 1 5 ~. 3 ~ 2 which is provided to create a stream of fibers that is used to form the dusting layer, is longitudinally aligned with but laterally spaced from both the first and third ports 202 and 20~, but i5 laterally aligned with but longitudinally space from a portion of 5 the second port 204. While the ports may be longitudinally and laterally arranged in a number of different configurations, the configuration shown in Figure 2 is especially preferred to provide a fibrous web having two core components, one of the components having discrete particles of absorbent gelling material dispersed 10 through one of its layers.

The first and third ports 202 and 206 are preferably centered relative to the second port 204 on the outer edges of the splitting member 200 so as to accommodat~ variations in the width of the drylap sheet that is fed into the disintegrator 26. Because 15 the fiber streams that are formed from the first and thi~d ports 202 and 206 are merged in the first deposition chute 36 downstream of the splitter chute 32, if there are any major variations in the width o~ the drylap sheet 24, this variation will not cause a significant change in the basis weight of the web 20 component ~ insert layer) formed by the first and third fiber streams because they are merged into a combined or primary fiber stream. Thus, the first and third ports 202 and 206 should haYe equal widths and be positioned symmetrically about the centerline of the splitter chute 32 or splitting member 200.

While the dusting layer port 208 is preferably laterally spaced and longitudinally spaced from all of the ports so ttlat the column of fibers is more efficiently split into four fiber streams, space and size constraints require that the preferred embodiment of the splitter chute 32 have the dusting layer port 208 laterally aligned with a portion of the second port 204 and longitudinal7y aligned with the first and third ports 202 and 206. The dusting layer port 208 is laterally aligned with a portion of the second port 204 because the second port 204 is preferably much wider than the first and third ports 202 and 206 such that the loss of such a small stream of fibers will have a minimal effect on the 1 ~ 1 3 ~ 2 ultimate basis weight of the core component formed by the second fiber stream. As shown in Figure 2, the dusting layer port 2Q8 is preferably laterally spaced from the centerline of the splitter chute 32 toward an edge of the second port 204 so that any effect that the removal of the dusting layer fiber stream has on the basis weight of the hourglass shaped core component is centered along the ears of the shaped core component rather than in the primary absorbent area of the shaped core component.

The conduit ducts provide a means through which a cslumn of high velocity air well as streams of air-entrained fibers are directed or conveyed. The conduit ducts may be separate elements such as pipes, channels or clucts which are secured to the splitting member 200 adjacent the ports, or an integral element formed by the positioning of plates as is shown in Figure 4, 5 and 6. The conduit ducts shou1d be configured for flow rates of preferably greater than or equal to about 75 ACFM per inch of disintegrating element 28 width and for velocities of preferably greater than or equai to about 6,000 feet per minute, more preferably about 10, 000 fpm . Thus it is preferable to make the conduit ducts about 1 inch thick and as wide as required to be in complete communication with the full width of the particular port with which the duct is in communication. While the conduit ducts may have any particular cross-sectional shape, rectilinear ducts or curvilinear ducts having a radius of curvature greater than about 6 inches are especially preferred. While rectilinear conduit chutes minimize air and fiber turbulence within the ducts, especially when such ducts are disposed tangentially to the curvilinear surface of the splitting member 200 adjacent tha2 particuiar port, curvilinear ducts are especially preferred due to 30 ~ size and shape cons~raints and equipment arrangement.

~he inlets of the conduit ducts provide a means to inject or draw ambient air into the conduit ducts at relatively high velocities. While the inlet ports may take on a number of different configurations, a configuration having an aerodynamic 131~2 shape is believed to function to minimize air turbulence as the air is drawn into the conduit duct.

A preferred configura.ion of the discharge outlets along the base 218 of the splitter chute 32 is shown in Figure 3. The first and third discharge outlets 234 and 238 are preferably aligned across the width of the base so that the first deposition chute 210 which merges the fiber streams downstream may conveniently be secured to both discharge outlets. The dusting layer discharge outlet 240 is slightly offset from the first and third discharge outlets 234 and 238 to more easily accommodate the dusting layer deposition chute. The second disoharge outlet 236 is set apart from all of the other discharge outlets due to the configuration of the second conduit duct and to facilitate equipment arrangements of two laydown drums.

The percentage of the total airfelt weight per absorbent core that will form each of the specific core components will vary according to the size of the absorbent article that is being manufactured. Thus a large diaper may require a greater percentage of the total airfelt weight in the shaped core component than a medium diaper. E3ecause the axial width of the ports determine the percentage of airfelt dedicated to each core component, it is preferable that the axial width of each port across the total axial width of the splitting member 200 be able to be changed according to the core component airfelt weights.
Accordingly, the splitter chute 32 is preferably manufactured from a series of plates that are bolted or otherwise secured together in any conventional manner to ~orm varying si~e chambers so that the width of each port, and correspondingly the width of each conduit duct, may be varied to accommodate the particular basis weight required in the final core component.

Figure 4 shows a cross-sectional view of a preferred embodiment of the splitter chute 32 taken along sectional line 4-4 of Figure 2. The cross-sectional view iilustrates the configuration of the splitting member 20û, the third port 206, and 18 ~.3~42 the third conduit duct 214 having an inlet 237 and a discharse outlet 238 in the third chamber or splitting region of the splitter chute 32. (While the present invention will be described with reference to the third chamber or splitting region, it should be understood that the description is equally applicable to the first chamber or splittiny region. ) The above elements are preferably formed and defined by three plates comprising a top plate 400, a downstream plate 402, and a base plate 404.

The top plate 400 defines a portion of the top wall 228 or splitting member 200 of the present invention as well as a top wall of the third conduit duct 214, a portion of the inlet 237, and the upstream edge 406 of the third port 206. The portion of the top plate 400 that defines the upstream edge 406 of the third port 206 is shown to be tapered away from the circular profile of the splitting member 200. This configuration is preferred so that the portlon of the column of fibers directed in ~he third chamb~r will begin to depar$ from the disintegrating element 28 due to the lack of constraint provided by the tapered upstream edge 406 as well as the fact that each fiber has an angular velocity component directed tangentiaily to its an~ular path which tends to direct or release the fibers away from the disintegrating element 28.

The downstream plate 402 defines the portion of the splitting member 200 that is downstream-of the third port 206, a portion of a wall of the third conduit duct 214, and a portion of the base ~18 of the splitter chute 32. Additionally, the downstream pl~te 1~02 defines the downstream edge or doctor's edge 408 of the third port 206. In conventional disintegrating apparatus, this doctor's edge is a point where a signlfiant amount of the fibers are removed from the teeth ;of the disintegrating element and directed into a conduit duct. The result of this removal at the doctor's edge causes a significant amount of fiber clumping along the doctor's edge. However, the term "doctor's edge" is used herein for descript~ve purposes. Very little, if any, fibers are removed from the teeth 74 of the disintegrating element 2~ by this edge.
Mos~ of the fibers are removed by the effects of the pressure 19 ~3~942 differential established adjacent the port and the angular velocity and momentum of the fibers as the fibers are drawn or pulled away from the disintegrating element. Thus, there is reduced fiber clumping along this doctor's edge 408.

The base plate 402 defines a wall of the third conduit duct 214, as well as a portion of the base 218 and side wall 224 of the splitter chute 32.

Figure 5 shows a cross-sectional view of a preferred embodiment of the splitter chute taken along sectional line 5-5 of Figure 2. The cross-sectional view illustra~es the configuration of the splitting member 200, the second port 204, an<:l the second conduit duct 212 having an inlet 235 and a dis harge outlet 236 in the second chamber or splitting region of the spli~ter chute 32.
(This portion of the second chamber i5 where no dusting layer 1~ flber stream is formed. ) The above elements are preFerably ~ormed and defined by three plates comprising a top plate 5ûO, a downstream plate 502 and a base plate 501~. These plates are arranged in a similar manner and define similar portions of the splitter chute as the plates shown in Figure 4 except that the second port 204 and the second conduit ducts 212 are arranged downstream along the splitting member 200 from where the first and third ports 202 and 206 are disposed. The upstream edge 506 and the doctor's edge 508 of the second port are also shown in Figure 5.

Figure 6 shows a cross-sectional viaw of a preferred embodiment of ~he splitter chute 32 taken along sectional line 6-6 of Figure 2. The cross-s,ectionai view illustrates the configuration of the ~ splitting member 200, the dusting layer port 208, the second port 204, the dusting layer conduit duct 216 having an inlet 239 and a discharge outlet 24û and the sec~nd conduit duct 212 having an inlet 235 and a discharge outlet 236, : in the dusting layer chamber or splitting ragion of the splitter chute. While the dusting layer chamber may be configured in a number of different ways, including the configuration shown in ::

20 ~ 2 Figure 4 wherein the second port and duct would not be formed in the dusting layer chamber, such embodiments are not preferred. The above elements are preferably formed and defined by six plates comprising a top plate 600, an intermediate plate 602, a downstream plate 604, a side plate 606, a base plate 608, and a wedge plate 610.

The splitting member 200 is formed from the top surfaces of the top plate B00, the intermediate plate 602 and the downstream plate 604. The intermediate plate 602 acts as a separator to define the ports. The dusting layer port 208 is defined by the top plate 600 and the intermediate plate 602; the top plate 600 defining the upstream edge 612 of the dusting layer port 208 and the intermediate plate 602 defining the doctor's edge 614 of the dusting layer port 208. The second port 204 is defined Sy the intermedia~e plate ~02 and the downstream plate 604 the intermediate plate 604 defining the upstream edge 508, and the downstrearn plate 604 defining the doctor's edge 510 of the second port ~04. The dusting layer conduit duct 216 is formed by the top plate 600, the side piate 606, the intermedi~te plate 602, and 2~ the base plate 608. The second conduit duct 212 is defined by the intermediate plate 602, the downstream plate 604 and ehe base plate 608. It should be noted that the second conduit duct 212 is blocked by the wedg,e plate 610. The wedge plate 610 is a plate having tapered ends and a square hole cut vertically through the plate so ac to block the flow of air through the portion of the second conduit duct 212 which is in comrnunication with the dusting layer conduit duct 216 while permitting the flow of air through the dusting layer conduit duct 216.

A particularly exemplary splitter chute 32 is configured of twenty-seven sets of plates across its width, each of the plates having a width of about five-eighths inch (about 15 . 8 mm) .
Thus, the cumulative width of the splitter chute 32 is about seventeen inches (about 432 mm). The first and third chambers are configured of from about four to about eight plates each such that the first and thircl ports 202 and 206 each have a width of ~31~942 about 2.5 to about 5.0 inches ~about 63.5 to about 127 mm~. The second chamber is configured of from about thirteen to about twenty plates such that the width of the second port 204 is about 8 .12 to about 1~ . 5 inches (about 206 to about 317 . 5 mm) . Of 5 these thirteen to twenty plates about two to about four plates are configured to provide the dusting layer cham~er such that the dusting layer port 208 has a width of about 1 . 25 to about 2 . 5 inches (about 31 . 75 to about 63. 5 mm . ) . The dusting layer chamber being laterally spaced from the first chamber by at least two plates or about 1.25 inches ~about 31.75 mm).

The splitter chute 32 is preferably operated such that each column of air that is drawn through the conduit ducts has a velosity of about six-thousand to abou~ fifteen-thousand feet per minute (about 1.83 to about 4.57 km per minute) preferably 15 about ten-thousand feet per minute (3 . 05 km per minute) and a flow rate of from about 40 to about 100 ACFM per inch preferably about 75 ACFM per inch.

Figure 7 shows an expanded cross-sectional view of a preferred embodiment of the spl itter chute 32 adjacent any of the ports of the present invention. The disintegrating element 28 is shown to be rotating in a counter-clockwise direction. The splitting member 200 having a port 700 is shown to be a curvilinear surface formed by a top plate 702 and a downstream plate 704. The conduit duct 706 is formed from the surfaces of the top plate 702 the downstream plate 704 and the base plate 708 the inlet of the conduit duct 7~6 being designated 710 and the discharge outlet being designated 712. Also as shown in Figure 7 the disintegrating element 28 the splitting member 20a and the housing (not shown) define a narrow flow channel 714 through which the column of fibers 716 is directed. The upstream edge 718 of the port 700 (the edge of the top plate 702 adjacent the port 700~ is shown in Figure 7 to be tapered away from the disintegrating element 28. (As previously discussed this configuration is preferred so that the fibers may begin to release from the disintegrating element.) The doctor s edge 720 22 ~3~ ~94~

or downstream edge of the port 700 (the edge of the downstream plate 704 adjacent the port 700) is shown to have an included angle "A" as defined by the tangents to the surfaces of the ~?late. A tangent release point, designated by the "X" in Figure 5 7, is the point defined wherein the tangential component of angular velocity of the fiber is such that the fiber tends to release from its angular path away from the disintegrating element 28. Whi7e the tangent release point may be positioned either upstream or adjacent the port 700, it is preferable that the 10 tangent release point be configured slightly upstream of the port 700 to provide the maximum stripping effect while minimizing clumping .

It has been found that the geometry of the members may have an important determination upon whether fiber clumping can be minimized. The angle "8" formed between the upstream edge 718 and the doctor's edge 720 defines the actual opening of the port 700. The actual opening is preferably not gre~ter than about 60, more preferably about 15 to about 45 and most preferably about 30. The angle "C" defined by the angle between the tangent release point, X, and the doctor's edge 720 defines an effective opening of the port 700. The effective opening is preferably not greater than about 75, more preferably about 30 to about 60, and most preferably about 4Q to about 45.
Thus the tangent release point should not be disposed upstream of the port 700 by more than about fifteen degrees (15). It has also been found that the included angle, angle "A", is preferably about 15 to about 60, most preferably about 45. It should also be noted that the angle between the ports from center-to-center should preferably be not greater than about 90, more preferably about 30 to about 60, and most preferably about 45 to achieve a sufficient separation between the ports to minimize interaction between the ports.

Referring to Figure 7, the operation of the apparatus of this invention will be described. The column of fibers 716 is directed around the flow channel 714 along the splitting member 200 of the 23 1 3 ~ 2 splitter chute 32 by the pumping action of the disintegrating element 28~ The column of fibers 716 is directed along the curvilinear surfaca of the splitting member such that angul~r motion and thus angular velocity and momentum is imparted to each of the fibers in the column. A high velocity column of air is simultaneously directed through the conduit duct 706 and past the port 700. This column of air may be provided by any conventional means ( not shown ) su~h as a blower positioned to inject air through the inlet 710 of the conduit duct 706 or a vacuum means positioned downstream of the discharge outlet 712, preferably below the foraminous forming element of the drum-type airlaying apparatus so as to draw ambient air through the inlet 71û oF the conduit duct 706.

While not wishing to be bound by theory, by maintaining a column of high velocity air lat least about 6000 ~eet per minute, and more preferably about 10,00û feet per minute) flowing through the conduit ducts, it is believed that a pressure differential or low pressure zone is created between the pressure in the flow shannel and the pressure in the conduit duct adjacent to or below the ports. Because of the pressure differential created by the movement of the column of air and t5~e angular velocity and mass-derived momentum of the fibers, the fibers tend to pull away from the disintegrating element and be directed along the pathway created by the tapered edge of the upstream edge of the port while they are being drawn into the first conduit duct as result of the pressure differential. Thus the fibers need not be split-off by the mechanical action of a doctor's ed~3e, but are :split-off as a result of air and fiber momentum, thereby minimizing ciumping due to the absence of mechanical edges or : wa!ls.

The stream of fibers which is drawn into the conduit duct subsequently becomes entrained in the column of air, the resultant stream of air-entrained fibers being directed downstream and out of the discharge outlet into the corresponding deposition ~4 ~315~2 chute. This process is repeated along each of the ports so as to create multiple, independent streams of air-entrained fibers.

The deposition chutes provide a means for directing streams of air-entrained fibers from the splitter chute 32 to one of the 5 airlaying means and for depositing the fibers onto the airlaying means. The deposition chutes aiso preferably decelerate the air-entrained fiber streams and orient the fiber streams from the discharge outlets to be compatibie with the width and location of the airlaying means.

The deposition chutes may comprise any members that are known in the art that are capable of performing the above functions. Preferably, the deposition chutes comprise ducts that are designed so as to decelerate the fiber streams while minimize clumping of the fibers during their reorientation from the splitter 15 chute to the airlaying means. The deposi~ion chute should be designed to provide a reduction in air speed with a minimum of chute contraction and expansion angles. Preferably the chutes provide about a two-thirds reduction in air speed and mora preferably re~uce the air speeds by a factor of 3 so that the fibers do not impact the laydown drum at a high velocity. Thus, the walls of the deposition chutes should have various curves and tapers to provide a gradually increasing cross-sectional area to reduce the velocity of the fiber streams. The deposition chutes preferably have a rectangular cross sectional area.

As shown in Figure 7, the first deposition chute 36 preferably comprises a "Y-shaped" configuration so as to merge the first and third fiber streams into a primary or combined fiber stream. Preferably, the first deposition chute 36 is designed to minimize the turbulence encountered with the merging of the two fiber streams. Thus, this chute preferably uses a fifth order polynomial curve profile or other profiles having their first and second derivative equal to zero so as to blend the fiber streams into a single stream.

~ 3 ~
As shown in Figure 1, th~ apparatus 20 and more particularly the first deposition chute 36, is preferably provided with a means for providing discrete particles of absorbent gelling material. The absorbent gelling material injection apparatus 40 or maans mixes discrete particles of absorbent gelling material with the combined or primary stream of air-entrained fibers prior to ~he deposition of the stream onto the first airlaying means. An exemplary type of injection means is shown in U.S. Patent 4,551,191 issued to Ronald W.
Kock and John A. Esposito on November 5, 1985. The inj~ction means preferably comprises a hopper (not shown) ~or storing a quantity of a~sorbent gelling material, a feed device (not shown) for metering the release of absorbent gelling material through an inlet duct 172 into an eductor 174 which entrains the absorbent gelling material in air, and a spreading duct 176 which provides air-entrained absorbent gelling material particles to the fiber streams. The absorbent gelling material is then entrained in and mixed with the fiber streams be~ore the admixture is deposited on the laydown drum. Any other suitable injection means as are known in the art may also be used ~or the invention. In addition, any of the other deposition chutes may be provided with absorbent gelling material injection means as are required.
The uniting means or apparatus provide a means for uniting the web components. "Uniting" is used herein to denote that the webs are brought together in a direct or indirect relationships to form an airlaid fibrous web.
While many uniting apparatus are known in the art, a preferred uniting apparatus comprises a pair of uniting rolls upon which a continuous stream enwrapped insert core components are dirPcted to be positioned adjacent the shaped core components.

131~34~
~ 26 Any other uniting means, including embodiments wherein the insert csmponents are blown-off o~ the first airlaying means directly onto the shaped core components, are also contemplated by the presant invention.
The first and second airlaying means or apparatus, for forming fibrous webs are shown in Figure 1 to preferably comprise drum-type airlaying apparatus.
While the airlaying apparatus of the present invention may alternativ~ly comprise a number of different configurations such as a moving Poraminous scre~n, a drum-type airlaying apparatus is especially preferred.
Typical drum-type airlaying apparatus useful in the present invention are shown in U.S. Patent 4,388,056, issued to F.B. ~ee and 0. Jobes, Jr., on June 14, 1983, and Canadian Patent 1,243,817, issued November 1, 1988, B.R. Feist, J.E. Carstens and D.A. Peterson. While the present invention can be practiced using a drum-type airlaying apparatus either which forms an endless or continuous web or which forms discrete webs or articles, the following description will ba related to a drum-type airlaying apparatus for making discrete fibrous webs.
The first drum-type airlaying apparatus 34 is shown in Figure 1 to comprise a first deposition or laydown drum 100 having a foraminous forming elem~nt (not shown) disposed abou~ the drum's periphery; a ~irst scarfing roll 102; a first blow-off means for nozzle 104; a first take-away conveyor 62 disposed about mounting rolls 106;
and a first transfer vacuum box 108 positioned beneath the upper run o~ the take-away conveyor 62. The second drum-type airlaying apparatus 46 pre~erably comprises a second deposition or laydown drum 110 having a ~oraminous Porming element (not shown); a second scarfing roll 112; a second blow-o~ means or nozzle 114; a second taXe-away conveyor 66 disposed about mounting rolls 116; and a sacond transfer vacuum box 118 : ' 26a 1315942 positioned beneath the upper run of the second take-away conveyor 66. Means not shown in Figure 1 include means for driving the drums, differential pressure means including a vacuum plenum duct, fan and a fan drive to draw fiber-depleted air through either the foraminous forming elements and to exhaust the air out of the drum through a duct.

27 13159~2 Thus, the apparatus 20 provides a means for converting an endless length or roll of drylap material into a succession of fibrous webs for use as absorbent cores in disposable diapers, catamenial napkins and the like. As shown in Figure 1, a roll of 5drylap material 24 is unrolled into a sheet which is advanced to the disintegrator 26. The sheet is fed radially into the disintegrator 26 by the pair of counter-rotating metering infeed rolls 22. An inlet opening 80 in the housing 30 of the disintegrator 26 receives the fibrous sheet and guides it to the 10inner end of the housing 30 wher e the edge of the fibrous sheet is disintegrated into a column of fibers disposed across the axial width of the housing 30. The column of fibers is directed around the flow channel 78 by the pumping action of the disintegrating element 2~ to the splitter chute 32. The column of fibers is split 15into multiple fiber streams that are entrained in air by the splitter chute 32~ the air-entrained fiber streams being directed out of the splitter chute 32 into the deposition chutes.

A dusting layer fiber strearn 56 is directed through the dusting layer deposition chute 42 to the first iaydown drum 100 20where the fibers are deposited on the foraminous forming element of the first laydown drum 100. Preferably, a first fiber stream 54 and a third fiber stream (not shown) are merged in and directed through the first deposition chute 36 where the combined or primary fiber stream is mixed with discrete particles of 25absorbent gelling material that are injected into the first deposition chute 36 by the absorbent gelling material injection apparatus 4û. The resultant admixture is directed to the first laydown drum 100, whereupon the fiber/absorbent gelling material admixture is deposited an,d collected on the foraminous ~orming 30element over the dusting layer, downstream of the position where the dusting layer was forrned. The fiber-depleted entrainment air is drawn through the foraminous forming element by the vacuum maintained behind the foraminous forming element. The resultant first web component is then transferred to the flrst take-away 35conveyor 62 by the blow-off nozzle 104 and the transfer vacuum box 108 located under the conveyor belt. The second web 28 131~942 component is preferably formed in a similar manner as the first web component by directing a second fiber stream 58 through the second deposition chute 48, by depositing and coilecting the second fiber stream 58 on the foraminous forming element of the second laydown drum 100: and by transferring the resultant second web component onto a second take-away conveyor 66.

Before uniting the web components, the w~b components may be finished by different operations such as calendaring, enwrapping or reinforcing the webs as are known in the art. As shown in Figure 1, the first web component is enwrapped in tissue by means of a folding board, whereupon the continous stream of enwrapped first core components is directed to the uniting rolls. The web components are then unit~d by directing the continuous stream of enwrapped first web components over the uniting means or rolls 52 whereupon they are brought into contact with the second web component. Other converting operations as desired may then be effected upon the resultant fibrous web downstream from the uniting means or rolls 52 to produce a finished disposable absorbent article such as a disposable diaper.

Figure 9 shows an enlarged sectional view of a preferred embodiment of the first drum-type airlaying apparatus 34 of the present invention. As shown- in Figure 9, the apparatus for formTng fibrous webs having discrete particles dispersed therein or having a multiplicity of layers preferably comprises 2 laydown drum 100 having a ~oraminous forming element consisting of a plurality of formation cavities 1 2û circumferentially spaced about the~ periphery of the drum 100. The number of cavities 120 can ~ be Y~ried depending upon the size of the drum 100 or the size of the webs to be formed. In the embodiment shown, the drum 100 contains six cavities. A plurality of ribs 122 are mounted within ths interior of the drum 100 to define a dustincJ layer vacuum chamber 124,~ a first or primary vacuum chamber 126, a hold-down vacuum charnber 128, and a blow-off chamber 130 having a blow-off means or nozzle 104. Each of the vacuum chambers is 29 1 3159~2 connected to a suitable source of vacuum (not shown) by vacuum ducts (not shown). The apparatus also preferably comprises a dusting layer deposition means such as a dusting layer deposition chute 42 and hood 44 for directing a dusting layer stream of air-entrained fibers to a dusting layer sector 132 of the laydown drum 100. The dusting layer hood 38 has a first sector 134 that circumferentially spans the entire dusting layer vacuum chamber 1 2q and a second sector 135 that circumferentially spans a portion of the first vacuum chamber 126. A first or primary deposition means such as a first deposition chute 36 and hood 38 for directing a first stream of air-entrained fibers to a first sector 136 of the laydown drum 100 is also shown in Figure 9, the first hood 38 having sufficient circumferential span to enclose the remaining portion of the first vacuum chamber 126. The apparatus further comprises a scarfing roll 102 a sealing roli 137; and a take-away conveyor 62 having an endless stream of discrete fibrous webs 138 or insert core components moving on the conveyor 6~.

A critical feature of this învention is that the first vacuum chamber 126 is disposed not only subjacent the entire first hood 38 but also under the downstream or second sector 136 of the dusting layer hood 44 so that approximately equal pressures are established adjacent the intersection point 140 of the hoods.
Since each of the hoods preferably has a circumferential span of one complete cavity 120 ~measured from the edge of a first cavity to the same edge of a second cavity) or approximately 60 degrees for a six cavity drum, the first vacuum chamber 126 must have a circum~rential span of greater than one chamber or about 75 degrees for the embodiment shown in Figure 9. Although the circumferential span of that portion of the first vacuum chamber 126 under the dusting layer hood 44 (i.e. the circumfer~ntial span of the second sector t 36 of the dusting layer hood 44) has not been found to be particularly critical, there should be sufficient circumferential span as to allow a minimal transition zone between the dusting layer hood 44 and the first hood 38.
This miminal circumferential span decreases as the number of 131~9~2 cavities 120 increases and increases as the number of cavities 100 decreases .

Another critical feature is that a small gap 142 must exist between the outer surface of the laydown drum 100 and the point 5 of intersection 140 of the hoods to allow for equalization of pressure in the portions of each hood adjacent the intersection point. If no gap existed, then there could be differential pressures in each hood so that as the drum brought the edgs of the dusting layer into the first hood 38, this pressure differential 10 could cause the dusting layer to lift off of the screen or shear.
I f the gas is too large, the two deposition chutes essentially merge into one and the independent dusting layer concept is not achieved. Thus a gap 142 of not more than about one-half inch is desirable with a one-eighth inch gap being preferable so that 15 the pressure may equalize in each portion of each hood that is adjacent to the intersection point 140.

Another important design criteria is that each of th~ hoods should have a relatively wide circular taper near the intersection point 140 so that the fibers that are directed toward the laydown drum in this area do not impinge on the dusting layer at an acute angle. When fibers impinge upon the dusting layer at an acute angle, the fibers have a component of velocity which is parallel to the surface of the drum, thus the fibers tend to cause the fibers constituting the dusting layer to lift or shear. The critical shear velocity has been determined to be about 4000 feet per minute;
the chute geometry being designed with this as a limiting factor.
Thus it is desirable that the fibers impinge upon the fibers of the dusting layer at an angle as close to perpendicular as possible because the shear component would not exist. Thus, each of the :: hQods should have a rçlatively wide circular taper so that the ;fibers do not impinge upon the dusting layes^ at an acute angle or exceed the critical shear velocity. As shown in Figure 9, each of the hoods has about 3 three inch radius of curviture adjacent the intersection point.

131 ~2 The operation of the apparatus is as follows. The dusting iayer stream of fibers is directed toward a circumferenti21 span or dusting layer sector 132 of the periphery of the laydown drum ! through the dusting layer deposition chute 42 and the dusting 5 layer hood 44. The circumferential span preferably being equal to the span of one cavity 120 or about 60degrees if six cavities l 20 are used. The fibers are deposited onto the foraminous forming elemant of one of the cavities 120 on the drum 100 while the entrainment air is being drawn through the foraminous 10 forming element by the vacuum maintained in the dusting layer vacuum chamber 124 as well as by the vacuum maintained in the primary or first vacuum chamber 126. Thus the dusting layer is formed by the collected fibers on the foraminous ~orming element.

As the drum rotates, the dusting layer passes from the 15 influenee of the dusting hood 44 to the influence of th2 first nood 38 where a first stream of air-entrained fibers are being directed generally radially toward the p2riphery of the drum. However, it should be noted that the dusting layer has already been transferred to the influence of the first vacuum chamber 126 prior 20 to passing ~etween the hoods such that the pressure differential and veloci~y of the first stream do not have a tendency to shear the dusting layer apart. The fibers of the first fiber stream are thus deposited over the dusting layer while the entrainment air is drawn through the foraminous forming element by the vacuum maintained in the primary or first vacuum chamber 126. The first or primary layer is formed by the collected fiber/AGM admixture over the dusting layer. Since the dusting layer is substantially left intact, discrete particles of absorbent gelling material do not tend to be drawn through the foraminous forming element nor p!ug it due to the blocking effect of having a layer of fibers already covering the void spaces in the foraminous forming element .

The resultant fibrous web then passes under the scarfing rol 1 102 where the web is leveled . The fibrous web 138 or insert 3~ core component is then transferred to the take-away conveyor 62 . 32 by the joint action of the blow-off nozzle t 04 and the vacuum maintained underneath the conveyor belt. The fibrous web 138 is then conveyed downstream to subsequent converting operations to produce a finished disposable absorbent article such as a 5 disposable diaper.

While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various changes and modifications can be made without departing from the splrit and scope of the invention. It is intended to cover, in the appended claims, all such modifications and intended uses.

Claims

1. An apparatus for providing a multiplicity of streams of air-entrained fibers by splitting a column of fibers into multiple fiber streams and by independently entraining each of the fibers streams in air, 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 second port circumferentially spaced downstream and completely axially offset from said first port, wherein a column of fibers is directed along said surface of said splitting member to said ports;

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 entraining the first fiber stream in the air to direct the first fiber stream downstream, and 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 entraining the second fiber stream in the air to direct the second fiber stream downstream.

2. The apparatus of Claim 1 wherein said second port is longitudinally spaced downstream of said first port.

3. The apparatus of Claim 2 wherein said second port is completely laterally spaced from said first port.

4. The apparatus of Claim 1 wherein said splitting member additionally comprises a third port laterally spaced from said first port and said second port, and further comprising a third conduit duct for directing a column of air past said third port so as to cause a portion of the column of fibers to split off and be drawn into said third conduit duct to form a third fiber stream, and for entraining the third fiber stream in the air to direct the third fiber stream downstream, said third conduit duct being in communication with said third port.

5. The apparatus of Claim 4 wherein said third port is longitudinally alighed with said first port.

6. The apparatus of Claim 5 wherein said second port is disposed between said first port and said third port,

7. The apparatus of Claim 6 wherein said first port and said third port are symmetrically disposed about the centerline of the apparatus.

8. The apparatus of Claim 7 wherein said splitting member additionally comprises a dusting layer port longitudinally aligned with and laterally spaced from said first port and laterally aligned with and longitudinally spaced from a portion of said second port, and additionally comprising 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 being in communication with said dusting layer port.

9. The apparatus of Claim 1 wherein said splitting member comprises a duct.

10. The apparatus of Claim 1 wherein said splitting member is circular.

11. The apparatus of Claim 1 wherein each of said conduit ducts is disposed tangentially to said curvilinear surface of said splitting member adjacent its respective port.

12. The apparatus of Claim 1 wherein each of said conduit ducts is curvilinear and has a radius of curvature of not less than about six inches.

13. The apparatus of Claim 1 wherein each of said conduit ducts has an inlet port and said inlet port has an aerodynamic shape.

14. The apparatus of Claim 1 wherein said conduit ducts are rectilinear.

15. The apparatus of Claim 1 wherein each of said conduit ducts is a separate element secured to said splitting member adjacent its respective port.

16. The apparatus of Claim 1 wherein said ports each has an upstream edge and a doctor's edge disposed on the downstream side of each of said ports.

17. The apparatus of Claim 16 wherein said upstream edge of each of said ports is tapered away from the path of the column of fibers so that the fibers tend to pull away from their path of travel and be directed along the pathway created by the taper of said upstream edge.

18. The apparatus of Claim 16 wherein said ports each has an actual opening of between about 15° to about 45°.

19. The apparatus of Claim 18 wherein said ports each has an effective opening of between about 30° and about 60°.

20. The apparatus of Claim 19 wherein said second port is circumferentially disposed downstream between about 30° and about 60° from said first port.

21. The apparatus of Claim 20 wherein said doctor's edges each has an included angle of between about 30° and about 60°.

22. The apparatus of Claim 21 wherein said upstream edge of each of said ports is tappered away from the path of the column of fibers so that the fibers tend to pull away from their path of travel and be directed along the pathway created by the taper of said upstream edge.

23. The apparatus of Claim 16 wherein each of said ports has a tangent release point positioned adjacent said port.

24. The apparatus of Claim 23 wherein said tangent release point is positioned upstream of said upstream edge of each of said ports by not more than about 15°.

25. The apparatus of Claim 16 wherein said ports each has an actual opening of not greater than about 60°.

26. The apparatus of Claim 16 wherein said second port is circumferentially disposed downstream not greater than about 90° from said first port.

27. The apparatus of Claim 26 wherein said second port is circumferentially disposed downstream between about 30° to about 60° from said first port.

28. The apparatus of Claim 25 wherein said ports each has an effective opening of not greater than about 75°.

29. The apparatus of Claim 28 wherein said second port is circumferentially disposed downstream not greater than about 90° from said first port.

30. The apparatus of Claim 29 wherein said doctor's edges each has an included angle of between about 15° and about 60°.

31. The apparatus of Claim 30 wherein said upstream edge of each of said ports is tapered away from the path of the column of fibers so that the fibers tend to pull away from their path of travel and be directed along the pathway created by the taper of said upstream edge.

32. The apparatus of Claim 31 wherein each of said conduit ducts is curvilinear and has a radius of curvature of not less than about six inches.

33. The apparatus of Claim 32 wherein each of said conduit ducts is disposed tangentially to said curvilinear surface of said splitting member adjacent its respective port.

34. The apparatus of Claim 33 wherein each of said conduit ducts is a separate member secured to said splitting member adjacent its respective port.

35. The apparatus of Claim 33 wherein said splitting member additionally comprises a third port circumferentially aligned with said first port and completely axially offset from said first port and said second port, said second port being disposed between said first port and said third port, and further comprising a third conduit duct for directing a column of air past said third port so as to cause a portion of the column of fibers to split off and be drawn into said third conduit duct to form a third fiber stream, and for entraining the third fiber stream in the air to direct the third fiber stream downstream, said third conduit duct being in communication with said third port.

36. The apparatus of Claim 35 wherein said splitting member additionally comprises a dusting layer port circumferentially aligned with and completely laterally spaced from said first port and laterally aligned with and circumferentially spaced from a portion of said second port, and additionally comprising 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 being in communication with said dusting layer port.

37. The apparatus of Claim 36 wherein said dusting layer port is laterally spaced from the centerline of and toward a lateral edge of said second port.

38. The apparatus of Claim 37 wherein said curvilinear surface of said splitting member is circular.

39. A splitter chute apparatus for providing a multiplicity of streams of air-entrained fibers by splitting a column of fibers into multiple fiber streams and by independently entraining each of the fiber streams in air, said splitter chute apparatus 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 second port at least partially axially offset from said first 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 first fiber stream, and for entraining the first fiber stream in the air to direct the first 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 second conduit duct for directing a column of air past said second port so as 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, said second conduit duct having an inlet and a discharge outlet, said second conduit duct being in communication with said second port.

40. The splitter chute apparatus of Claim 39 wherein said second port is circumferentially spaced downstream and completely axially offset from said first port.

41. The splitter chute apparatus of Claim 40 wherein said ports each has an upstream edge and a doctor's edge disposed on the downstream side of each of said ports.

42. The splitter chute apparatus of Claim 41 wherein said ports each has an actual opening of not greater than about 60°.

43. The splitter chute apparatus of Claim 42 wherein said second port is circumferentially disposed downstream not greater than about 90° from said first port.

44. The splitter chute apparatus of Claim 43 wherein said ports each has an effective opening of not greater than about 75°.

45. The splitter chute apparatus of Claim 44 wherein said doctor's edges each has an included angle of between about 15° and about 60°.

46. The splitter chute apparatus of Claim 45 wherein said upstream edge of each of said ports is tapered away from the path of the column of fibers so that the fibers tend to pull away from their path of travel and be directed along the pathway created by the taper of said upstream edge.

47. The splitter chute apparatus of Claim 46 wherein said inlet of each of said conduit ducts is positioned in said first side wall.

48. The apparatus according to Claims 8, 26, 33, 41 or 47 further comprising:

a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said housing.

49. The splitter chute apparatus of Claim 47 wherein said discharge outlet of each of said conduit ducts is positioned in said second side wall.

50. The splitter chute apparatus of Claim 47 wherein said discharge outlet of each of said conduits ducts is positioned in said base.

51. The splitter chute apparatus of Claim 50 wherein each of said conduit ducts is curvilinear and has a radius of curvature of not less than about six inches.

52. The splitter chute apparatus of Claim 51 wherein each of said conduit ducts are integral with the splitter chute apparatus.

53. The apparatus of Claim 52 wherein said inlet of each of said conduit ducts has an aerodynamic shape.

54. The splitter chute apparatus of Claim 52 wherein said top wall additionally comprises a third port circumferentially aligned with said first port and completely axially offset from said first port and said second port, said second port being disposed between said first port and said third port, and wherein said first port and said third port are symmetrically disposed about the axial centerline of the splitter chute apparatus; and further comprising a third conduit duct for directing a column of air past said third port so as to cause a portion of the column of fiber to split off and be drawn into said third conduit duct to form a third fiber stream, and for entraining the third fiber stream in the air to direct the third fiber stream downstream, said third conduit duct being in communication with said third port.

55. The splitter chute apparatus of Claim 54 wherein said top wall additionally comprises a dusting layer port circumferentially aligned with and completely laterally spaced from said first port and said third port, and laterally aligned with and circumferentially spaced from a portion of said second port; and additionally comprising 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 being in communication with said dusting layer port.

56. The splitter chute apparatus of Claim 55 wherein said apparatus comprises a plurality of plates secured together.

57. The splitter chute apparatus according to Claim 39 further comprising:

a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said splitter chute apparatus.

58. The apparatus of Claim 57 wherein said splitter chute apparatus is integral with said housing.

59. The apparatus of Claim 58 wherein said base of said splitter chute extends beyond said lateral side walls to define flanges having bores so that said splitter chute may be secured to said housing.

60. The apparatus of Claim 58 additionally comprising a flow channel formed between said disintegrating element and said housing and between said disintegrating element and said top wall of said splitter chute apparatus, said flow channel having a clearance between about 0.79 mm and about 6.35 mm.

61. The apparatus of Claim 60 wherein said flow channel, said housing, said disintegrating element, and said top wall of said splitter chute define a splitting member.

62. A method for splitting a column of fibers into a multiplicity of streams of air-entrained fibers, the method comprising the steps of:

providing a column of fibers;

directing said column of fibers along the surface of a curvilinear splitting member having a plurality of ports comprising a first port and a second port;

imparting angular velocity and momentum to said column of fibers;

directing a first column of air through a first conduit duct past the first port so as to create a pressure differential adjacent the first port:

releasing a first portion of said column of fibers away from its angular path of travel;

drawing said first portion of said column of fibers through the first port into the first conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent the first port so as to form a first fiber stream;

entraining said first fiber stream in the first column of air;
directing the first stream of air-entrained fibers downstream;

directing a second column of air through a second conduit duct past the second port so as to create a pressure differential adjacent the second port;

releasing a second portion of said column of fibers away from its angular path of travel;

drawing said second portion of said column of fibers through the second port into the second conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent the second port so as to form a second fiber stream;

entraining said second fiber stream in the second column of air; and directing the second stream of air-entrained fibers downstream.

63. The method of Claim 62 additionally comprising the steps of:

directing said column of fibers along the splitting member additionally having a third port:

directing a third column of air through a third conduit duct past the third port so as to create a pressure differential adjacent the third port;

releasing a third portion of said column of fibers away from its angular path of travel;

drawing said third portion of said column of fibers through the third port into the third conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent the third port so as to form a third fiber stream;

entraining said third fiber stream in the third column of air;
and directing the third stream of air-entrained fibers downstream.

64. The method of Claim 63 wherein said third portion of said column of fibers is simultaneously drawn into the third conduit duct as said first portion of said column of fibers is drawn into the first conduit duct.

65. The method of Claim 64 wherein said second portion of said column of fibers is drawn into the second conduit duct after said first portion of said column of fibers is drawn into the first conduit duct.

66. The method of Claim 65 wherein said first portion and said third portion of said column of fibers comprise the edge portions of said column of fibers.

67. The method of Claim 65 additionally comprising the steps of:
directing said column of fibers along the splitting member additionally having a dusting layer port:

directing a dusting layer column of air through a dusting layer conduit duct past the dusting port so as to create a pressure differential adjacent the dusting layer port;

releasing a dusting layer portion of said column of fibers away from its angular path of travel;

drawing said dusting layer portion of said column of fibers through the dusting layer port into the dusting layer conduit duct as a result of the angular momentum of the fibers and the pressure differential formed adjacent to the dusting layer port so as to form a dusting layer fiber stream;

entraining said dusting layer fiber stream in the dusting layer column of air; and directing said dusting layer stream of air-entrained fibers downstream.

68. The method of Claim 67 wherein said dusting layer portion of said column of fibers is simultaneously drawn into the dusting layer conduit duct as said first portion of said column of fibers is drawn into the first conduit duct.

69. The method of Claim 63 wherein said column of fibers is released from its angular path of travel not more than about 15° upstream of the upstream edge of the ports.

70. The method of Claim 69 wherein said columns of air each is directed tangentially past its respective port.

71. The method of Claim 62 wherein said second portion of said column of fibers is drawn into the second conduit duct after said first portion of said column of fibers is drawn into the first conduit duct.

72. The method of Claim 62 wherein said column of fibers is released from its angular path of travel not more than about 15° upstream of the upstream edge of the ports.

73. The method of Claim 62 wherein said columns of air each is directed tangentially past its respective port.

74. The method of Claims 62, 66, 68 or 70 wherein the step (a) of providing a column of fibers comprises the steps of:

providing a fibrous sheet;

feeding the fibrous sheet into a disintegrator having a disintegrating element and a housing;

separating the fibers of the fibrous sheet by impacting the teeth of the disintegrating element on the end of the fibrous sheet:

forming a column of fibers across the axial width of the housing.

75. The apparatus of Claim 18 wherein said second port is circumferentially disposed downstream not greater than about 90° from said first port.

76. The apparatus of Claim 75 wherein said second port is circumferentially disposed downstream between about 30° to about 60° from said first port.

77. The apparatus of Claim 25 wherein said second port is circumferentially disposed downstream not greater than about 93° from said first port.

78. The apparatus of Claim 77 wherein said second port is circumferentially disposed downstream between about 300 to about 60° from said first port.

79. The splitter chute apparatus according to Claim 40 further comprising:

a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said splitter chute apparatus.

80. The splitter chute apparatus according to Claim 54 further comprising:

a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said splitter chute apparatus.

81. The splitter chute apparatus according to Claim 55 further comprising:
a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said splitter chute apparatus.

82. The splitter chute apparatus according to Claim 56 further comprising:
a disintegrator for fibrous material comprising a rotary cylindrical disintegrating element, and a housing for said disintegrating element joined to said splitter chute apparatus.

83. The apparatus of any of Claims 40, 54, 55 or 56 wherein said splitter chute apparatus is integral with said housing.

84. The apparatus of any of Claims 40, 54, 55 or 56 wherein said splitter chute apparatus is integral with said housing and said base of said splitter chute extends beyond said lateral side walls to define flanges having bores so that said splitter chute may be secured to said housing.

85. The apparatus of and of Claims 40, 54, 55 or 56 wherein said splitter chute apparatus is integral with said housing and said base of said splitter chute extends beyond said lateral side walls to define flanges having bores so that said splitter chute may be secured to said housing, additionally comprising a flow channel formed between said disintegrating element and said housing and between said disintegrating element and said top wall of said splitter chute apparatus, said flow channel having a clearance between about 0.79mm and about 6.35mm.

86. The apparatus of any of Claims 40, 54, 55 or 56 wherein said splitter chute apparatus is integral with said housing and said base of said splitter chute extends beyond said lateral side walls to define flanges having bores so that said splitter chute may be secured to said housing, additionally comprising a flow channel formed between said disintegrating element and said housing and between said disintegrating element and said top wall of said splitter chute apparatus, said flow channel having a clearance between about 0.79mm and about 6.35mm, and wherein said flow channel, said housing, said disintegrating element, and said top wall of said splitter chute define a splitting member.