U.S. patent number 3,760,458 [Application Number 05/201,002] was granted by the patent office on 1973-09-25 for method and means for strand filament dispersal.
This patent grant is currently assigned to Owens-Corning Fiberglas Corporation. Invention is credited to Richard E. Pitt.
United States Patent |
3,760,458 |
Pitt |
September 25, 1973 |
METHOD AND MEANS FOR STRAND FILAMENT DISPERSAL
Abstract
A method and means for the production of fibrous strand mats by
collecting multi-filament strands in mat-like form, flooding the
mat with a liquid to overcome forces holding filaments together in
a strand, retaining the mat in the flooded condition for a
predetermined interval, and removing excess liquid from the
collection after the filaments are dispersed.
Inventors: |
Pitt; Richard E. (Newark,
OH) |
Assignee: |
Owens-Corning Fiberglas
Corporation (Toledo, OH)
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Family
ID: |
27544173 |
Appl.
No.: |
05/201,002 |
Filed: |
November 22, 1971 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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869951 |
Oct 27, 1969 |
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531992 |
Mar 4, 1966 |
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Current U.S.
Class: |
28/283; 19/299;
19/302 |
Current CPC
Class: |
D04H
3/02 (20130101); D04H 3/03 (20130101) |
Current International
Class: |
D04H
3/02 (20060101); D04H 3/03 (20060101); D01d
011/02 () |
Field of
Search: |
;65/3,4,9,11
;156/62,62.6,62.8,4 ;8/151,151.2,156,159 ;68/52,55,62 ;18/8
;19/65T,66T,155 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Newton; Dorsey
Parent Case Text
This is a continuation of my co-pending application Ser. No.
869,951, filed Oct. 27, 1969 now abandoned, which was a
continuation of my then co-pending application Ser. No. 531,992,
filed Mar. 4, 1966, and now abandoned.
Claims
I claim:
1. A method for the production of a mat-like collection of
filaments wherein the orientation of the filaments is controlled
comprising the steps of
a. providing multi-filament strands in an unwoven mat-like form on
a moving surface,
b. flooding said mat-like collection on said moving surface with a
liquid to overcome forces holding filaments together in a
strand,
c. creating stream flow of said liquid through said flooded area in
the same direction with and at substantially the same rate as said
mat-like collection is moving through said flooded area to avoid
disorientation of said strands from their positions in said
mat-like collection on said surface,
d. retaining said mat-like collection in said flooded condition for
an interval until filaments of the strands are dispersed within the
general orientation of said strands on said surface, and
e. removing excess liquid from the mat-like collection after said
filaments are dispersed to provide a mat-like collection of
oriented filaments on said surface.
2. A method as defined in claim 1 in which said excess liquid
removal step includes draining said excess liquid through said
mat-like collection to cause said dispersed filaments to be carried
in a hole-seeking flow of said draining liquid through said
mat-like collection to remove voids in said mat-like
collection.
3. A method as defined in claim 1 in which said stream flow
creating step includes adding liquid across an initial portion of
said flooded area to replace the liquid carried out of said flooded
area by said mat-like collection.
4. A method for the production of a mat-like collection of
individual glass fibers wherein the orientation of the fibers
within the collection is controlled, comprising the steps of
a. depositing multi-filament strands of glass fibers on a
collection surface in a mat-like form,
b. flooding said mat-like form on said collection surface with a
liquid without disturbing the general orientation of the glass
fiber strands in the mat-like form.
c. retaining said mat-like form in said flooded condition for an
interval until fibers of the strands are dispersed from each other
within the general orientation of the strands in the mat-like form,
and
d. removing excess liquid from the mat-like form after said fibers
are dispersed by draining said liquid through said mat-like form
and said collection surface to cause individual fibers to be
carried in a hole-seeking flow of said draining liquid through said
mat-like form to remove voids in said mat-like form.
5. Apparatus for the production of a mat-like collection of
individual glass fibers wherein the orientation of the fibers
within the collection is controlled, comprising
a. an element having a foraminous collection surface,
b. means providing multi-filament strands of glass fibers in an
unwoven mat-like form on said collection surface,
c. means for flooding said mat-like form on said collection surface
with a liquid without disturbing the orientation of the glass fiber
strands in the mat-like form and for retaining said mat-like form
in said flooded condition until fibers of the strands are dispersed
from each other within the general orientation of the strands in
the mat-like form including means for moving said element having a
foraminous collection surface into and out of a flooding area,
and
d. means for removing excess liquid from the mat-like form after
said fibers are dispersed by draining said liquid through said
mat-like form and said foraminous collection surface causing
individual fibers to be carried in a hole-seeking flow of said
draining liquid to remove voids in said mat-like form.
6. A method for the production of fibrous strand mats comprising
the steps of
a. collecting multifilament strands in an unwoven mat-like form on
a surface,
b. flooding said mat-like collection on said surface with a liquid
to overcome forces holding filaments together in a strand, said
flooding including conveying said mat-like collection on said
surface through an area flooded with said liquid,
c. flowing said liquid through said flooded area in the same
direction with and at substantially the same rate as said mat-like
collection is conveyed through said flooded area to avoid
disorientation of said strands from the positions in said mat-like
collection,
d. retaining said mat-like collection in said flooded condition for
an interval until filaments of the strands are dispersed within the
general orientation of said strands on said surface,
e. adding an impingement of liquid to said flowing liquid and
flooded mat-like collection after said collection has traveled a
distance through said flooded area, said liquid impingement being
distributed evenly across said advancing mat-like collection and
having a relatively different velocity than said mat-like
collection and the accompanying flowing liquid to further disperse
said filaments, and
f. removing excess liquid from the mat-like collection after said
filaments are dispersed to hold said filaments in their dispersed
positions in the mat-like collection on said surface.
7. A method as defined in claim 6 in which said impingement liquid
adding step includes providing said impingement of liquid with a
relatively higher velocity than said flooding liquid, the velocity
having a greater vector substantially parallel to the direction of
flow of said flooding liquid.
8. Apparatus for the production of glass fiber strand mats having
filaments of said strands dispersed comprising
a. an element having a strand receiving surface,
b. means providing multi-filament glass fiber strands in an unwoven
mat-like form on said surface,
c. means for flooding said mat-like form on said surface with a
liquid to overcome forces holding filaments together in strand
form,
d. means for maintaining said mat-like form in said flooded
condition for an interval,
e. means for adding additional liquid to impinge upon said flooded
strands to further disperse said filaments, and
f. means for draining excess liquid through said mat-like form and
said surface after dispersal of said filaments to cause dispersed
filaments to be carried in a hole-seeking flow of said liquid
draining through said mat-like form to remove voids in said
mat-like form.
9. Apparatus for the production of glass fiber strands mats having
filaments on said strands dispersed comprising
a. an element having a strand receiving surface,
b. means providing multi-filament glass fiber strands in an unwoven
mat-like form on said surface,
c. means for flooding said mat-like form on said surface with a
liquid to overcome forces holding filaments together in strand form
including means for moving said mat-like form and said element
through said liquid,
d. means for maintaining said mat-like form in said flooded
condition for an interval,
e. means for adding liquid to said flooded mat-like form to create
a stream flow of said liquid in the same direction and at
substantially the same rate of movement as said conveyed mat-like
form, and
f. means for draining excess liquid through said mat-like form and
said surface after dispersal of said filaments to cause dispersed
filaments to be carried in a hole-seeking flow of said liquid
draining through said mat-like form to remove voids in said
mat-like form.
10. Apparatus as defined in claim 9 in which said liquid adding
means includes weir means located above said mat-like form to
distribute said liquid evenly across said mat-like form as it is
conveyed beneath said weir means.
11. Apparatus as defined in claim 9 which further includes means
for adding additional liquid to said flooded mat-like form at a
spaced distance from said first-mentioned liquid adding means to
impinge upon said flooded strands to cause further filament
dispersal.
12. Apparatus as defined in claim 11 in which said second-mentioned
liquid adding means comprises a weir means positioned to add liquid
evenly across said flooded strands as the strands are conveyed past
said second-mentioned liquid adding means.
13. Apparatus as defined in claim 12 which further includes means
for controlling the velocity and direction of said second-mentioned
liquid.
Description
Because of the increased general use of fibrous glass mat products,
need has arisen for more exacting characteristics and properties
for specific applications. Fibrous glass mats have been put to use
for such purposes as acoustical, electrical, and thermal insulation
as well as for reinforcing and filtering purposes, each such
application requiring certain characteristics of strenghth,
porosity and integrity.
One method by which glas fibers for mats can be produced is to
mechanically attenuate a plurality of glass streams flowing from a
feeder or bushing. Attenuation of the streams may be effected by
pulling rolls or wheels which draw the streams into fine fibers or
filaments as they solidify by reason of exposure to the atmosphere.
The solidified filaments are drawn over a size applicator and are
then gathered into strand form whereupon the pulling wheels supply
the strand for the purpose desired.
Another method of manufacturing glass fibers involves flowing the
glass from feeders as described above and directing a jet of gas
thereagainst at high speed to attenuate the streams into fine
fibers by disrupting them into varied lengths which collect as a
pulpy mass.
Sheet and mat products have been manufactured in the past of both
types of glass fibers but strand mats have presented a greater
difficulty in manufacture because of their limited ability to form
an integral mass. More specifically, the strand has little tendency
to intermingle with itself so as to promote formation of an
integral mass such as in a mat product. Heretofore, it has been
necessary to add agents such as extra quantities of binder material
or additional glass fibers of shorter length in order to promote
mat integrity. These additions, however, involved additional
process steps and correspondingly added quipment complexity and
cost.
In an effort to form a more integral mass, glass fiber strands have
been impinged or bounced off a deflecting surface to provide a
fluffy or fuzzy property. That is, an integral glass strand is
moved at a relatively high speed and directed against a hard
surface so that it impinges such surface with a driving force, the
product produced being a strand of fuzzy or fluffed character which
tends to take on a curl resulting in a generally helical form or
swirl. The greater the speed of impingement, the greater the
fuzziness created. The fuzziness results from filaments within the
strand being dispersed or separated from the main core along at
least a portion of their lengths while the remainder are retained
in integrated form. While this method did give a better degree of
fine porosity desired for use in acoustical, electrical and thermal
insulation, the abrading or mechanical handling of the glass strand
when deflecting the strand from a surface at a high speed is
undesirable since it tends to reduce the mechanical strength of the
strand or the filaments. Further, this method makes it difficult to
uniformly deposit the strand and filaments with great accuracy over
a predetermined area. Uniformity of deposition of strands upon a
collecting surface is a problem which also effects integrity of the
mat.
In addition to the problem of integrity, other difficulties are
experienced with strands in that of themselves they lack the
ability to give the degree of fine porosity desired for uses such
as acoustical, electrical and thermal insulation. That is,
continuous strands by themselves usually fail to provide the
multitude of small interstices desired in such insulation
materials. Further, in fine mat or thin mat applications where the
mat i used as a reinforcing material for such products as roofing
materials made from mats impregnated with asphalt, etc., the small
interstices are necessary to hold the molten or plastic filler or
impregnator and keep it from running on through the mat when the
mat is being combined with the filler to make the final product.
Also, in this regard, mats made in the past wholly of strand,
because of their unusually large interstices, are somewhat rough
and fail to provide the fine finish and appearance desired when the
glass mats are put to use as reinforcement material in resin
laminate structures, particularly when the laminate includes
semi-transparent portions.
It is particularly desirable to incorporate continuous glass
strands in mat products, however, because the mechanically
attenuated fibers of which such strands are composed have much
greater strength than the blown fibers. Such additional strength
incorporated into fibrous mats lends greatly to permitting their
use in many installations in which they could not otherwise be
used. Both burst and tear strengths of such mats can be made
extremely high by reason of the high strength of the fibers or
filaments embodied in the strands.
In view of the foregoing, it is an object of the present invention
to provide a novel and economical method and means for manufacture
of glass strand mats having a high degree of integrity and
strength.
Another object of this invention is to provide a new type of glass
strand mat having a high degree of integrity and strength and a
controllable degree of porosity.
A further object of the invention is to provide an efficient method
and means for dispensing filaments from a strand bundle to promote
integrity in accumulations of the strand bundles.
Still another object of this invention is to produce a novel strand
product capable of providing a large number of interstices and a
fine finish in accumulations thereof.
A still further object of the invention is to provide a more
efficient method and means than existed heretofore for
manufacturing mat products of materials in strand or yarn form.
An additional object of this invention is to provide method and
means for the dispersal of filaments after they are gathered in
strand form for the use in end products as desired.
It has been found that strands formed from a number of filaments in
a bundle may be reopened or have the filaments dispersed by the
impingement of a fluid stream upon the strand. While the fluid
stream may be a gaseous fluid, it most advantageously is shown in
most of the preferred embodiments herein as a liquid fluid to
accomplish the dispersal of the filaments as desired. There is
shown, however, a method and means for dispersing filaments of a
strand by the use of gaseous stream impingement. There is also
shown the method and means for the dispersal of strands by the use
of liquid streams thereon. To obtain an even greater dispersal, a
liquid stream may be impinged upon strands and the liquid retained
around the strands in a flooded condition to provide a "soaking" or
a weakening of bonding forces for a predetermined interval, after
which interval a second impingement of a liquid stream upon the
strands while still in a flooded condition will effect an even
further dispersal of the filaments from the strand.
The strength properties of the strand which have been dispersed or
reopened in this manner are not affected, as compared to mechanical
impingement of the strand on a hard deflecting surface. Better
dispersal can be obtained than by any other known method. The
dispersed or fuzzed characteristic of the filaments provides an
attribute which promotes mass integrity when the strand is in mat
form. The dispersion of filaments promotes an intermingling and
clinging of the strand portions which overlap and cross, or
otherwise contact each other, so as to produce a gathering of
filaments and strand into a cohesive mass. In addition, the
intermingling and clinging causes the formation of a multitude of
very small interstices desired in many products and also provides a
fine outer finish which is often desired when such a product is
used as reinforcement in resin laminate and other structures.
An important feature of this method of filament dispersion is that
it does not disturb the distribution or uniformity of distribution
or the original orientation of the strand in its particular
position in the mat. The strand can be distributed quite accurately
by newer methods and dispersion or reopening effected without
disturbing the uniformity of distribution thus achieving the finest
finish, the smallest interstices and the best integrity of any mat
product known to date. This particularly important factor is
necessary for the production of the very thin or "fine" mats which
are difficult to regulate in uniformity in a unit area and in
weight per unit area.
The invention thus features a method for dispersing filaments of a
strand comprising the steps of impinging the strand with a liquid
to overcome forces holding the filaments together in the strand and
removing the excess liquid after the filaments are dispersed. In a
preferred embodiment of the invention, the method includes the
steps of flooding the strand or the mat with the dispersing liquid.
This flooding step is advantageously accomplished by conveying the
strand or mat through a flooded area, which flooded area is
provided by impinging the mat from above with a liquid stream while
retaining the liquid around the mat as it moves forward.
Advantageously, the flooded liquid area around the mat moves with
the mat at substantially the same rate so that the orientation and
uniformity of distribution of the strands is not disrupted. Further
dispersion may be obtained by adding an impulse of liquid having a
relatively different velocity than the mat and the accompanying
flooding stream to further disperse the filaments. This additional
impulse of liquid is advantageously provided after the strands and
mat have a predetermined interval of soaking or dispersal in the
flooded area.
The excess liquid may be removed by vertically draining the liquid
through a foraminous conveyor, for example, so that the filaments
are further dispersed by being carried in the hole-seeking flow of
the liquid through the mat. This further removes voids in the mat
and places or leaves the filaments in the desired position due to
the vertical flow at the holes and through the small interstices.
The method may be further expanded to include impinging a filament
dispersing fluid stream against the strands as they are being
deposited upon a collecting surface or the conveying surface in mat
form. This pre-impingement may be either a gaseous or liquid fluid.
The method may also advantageously include a step of applying a
lubricant to the filaments when being formed into strands to
provide interfiber mobility to aid subsequent filament dispersion
steps. In brief, the method of dispersing the filaments of a strand
comprises the steps of applying a non-abrading force to the strand
to weaken the bonding forces holding the filaments in a strand
configuration and removing the force after predetermined dispersal
is obtained.
Novel apparatus for accomplishing the above inventive methods is
disclosed and described in detail for preferred embodiments
herein.
Although the principles of the present invention are described as
applied in the use of glass strands, the invention is not limited
thereto in view of the fact that it has aspects readily applicable
to use with strands, yarns and other forms of different materials.
For example, the described method of effecting filament dispersion
or strand reopening can be used for filament dispersion of yarns or
slivers as well, or may be used for strand reopening or filament
dispersion of strands, yarns or slivers of materials such as
cellulose acetate, artificial silk, cotton, wool and nylon.
Other objects, advantages and features of the invention will become
readily apparent when the following description is taken in
conjunction with the accompanying drawings, in which:
FIG. 1 is a front elevation of apparatus embodying a portion of the
teachings of this invention;
FIG. 2 is an enlarged plan view of the apparatus of FIG. 1;
FIG. 3 is a side elevation in section illustrating apparatus for
further dispersing filaments of strands;
FIG. 4 is an enlarged sectional side view of liquid distribution
apparatus suitable for use in this invention; and
FIG. 5 is a front elevational view of the liquid distribution
apparatus illustrated in FIG. 4.
Referring to the drawings in more detail, the apparatus of FIGS. 1
and 2 includes molten glasss feeding bushings 21 and 22 depending
from conventional glass melting tanks which are not illustrated.
The conveyor 61 includes the foraminous collecting surface elements
constituting the web of the conveyor, a conveyor drive rod or means
for moving the elements 61a, a drive motor 61c, and a
sprocket-chain arrangement generally indicated at 61b connecting
the motor 61c to drive roll 61a. Continuous filaments 23 are drawn
from the minute streams of molten glass issuing from orifices of
the bushing. It will be considered that a bushing with 400 orifices
is here utilized and the filaments are drawn to an average diameter
of fifty-five hundred thousandths of an inch.
Size or a lubricant may be applied to the filaments as the latter
pass over the traveling belts or aprons of the conventional size
applicators 25. The size may be merely water to reduce friction
between the filaments as they are subsequently joined in strand
form. A more complex size may be desired to promote inter-fiber
mobility of the filaments when combined as strands in order to aid
subsequent filament dispersion steps.
The filaments from each bushing after receiving a sizing if
desired, are grouped together to form a set or group of, in this
instance, 14 strands individually segregated as they travel within
14 grooves over the respective gathering shoe 27 to the second
gathering or aligning shoes 31.
From the shoes 31 the two set of spaced strands 29 and 30 are led
around the two idler wheels 33 and, respectively, travel around the
pull wheels 35 and 36. The wheels are similarly constructed but are
relatively reversed in position and are on opposite sides of the
center line of the receiving conveyor 61. The wheels and the
forming stations above them are meant to be representative of a
number of forming stations as required to build the thickness or to
provide the properties desired for the mat being formed.
Motors 37 and 38, respectively, drive pull wheels 35 and 36. The
strands carried by pull wheel 35 are released therefrom by the
successive projection of fingers of an oscillating spoke wheel
through slots in the peripheral surface of the pull wheel 35.
Similarly, fingers of another spoked wheel serve this purpose in
connection with the pull wheel 36. The strands are kinetically
projected in tangential paths from the pull wheel. That is, the
rotation of the pull wheels 35, 36 at high speeds imparts a kinetic
energy to each segment of the strand as it is pushed off the wheel.
Since the strand segments are all pushed off tangentially in the
same direction in this apparatus, the strand segments and thus the
entire strand acquires a linear velocity which is utilized in some
methods of uniformly distributing the strands.
The rear side of each pull wheel is covered by an independently
mounted, oscillatable back plate on which the associated spoked
wheel is carried. Back plate 42 of the assembly including pull
wheel 36 may be arcuately oscillated through arm 43. The entire
assembly may be positioned on the platform 50 to support the pull
wheels 35 and 36 and the equipment associated therewith. Platform
50 may be suspended by angle iron hangers 51. The arm 43 may be
arcuately turned to a position to determine the tangential push-off
of the strand from the pull wheel 36. If, as in this instance, it
is desired that the tangential push-off causes the strands to be
carried perpendicularly downwardly with their linear velocity, then
the arm 43 may be secured to hanger 51 by a link 52 to retain the
strand push-off at the position desired. The pull wheels just
described are particularly suited for use in this invention since
they allow the uniform distribution of a plurality of "finer"
strands, rather than a larger coarse strand. A finer strand lends
itself more readily to reopening techniques described herein.
The group of strands 58 thrown down by the pull wheel 35, which has
its push-off point also anchored by a link 52 connected to hanger
51, and the group of strands 59 thrown down by the pull wheel 36
are accumulated, after distribution, in mat form 60 upon the
collecting surface, in this case traveling conveyor 61, which may
be of a foraminous, perforated or mesh construction.
After the sets of strands 58 and 59 have had imparted thereto
kinetic energy and thus provided with a predetermined linear
velocity, aerodynamic diversion means, in this instance fluid
nozzle means 100, 101 and 102, 102 for the sets or groups 58 and
59, respectively, distribute the strands across the width of the
collecting surface.
In addition to aerodynamic diversion with sufficient linear
velocity to accurately deposit and distribute one or a plurality of
strands it has been discovered that another important function may
be provided by the fluid nozzles by the proper control, placement
and use thereof. That is, the aerodynamic diverting means can be
used to also disperse the filaments. A jet or fluid stream may be
used to flatten the strand from a generally cylindrical
cross-section to a substantially flat or ribbon cross-section
configuration. This flattening, while not effecting the linear
velocity of the strand required for accurate deposition, is
effective to weaken the bond holding the filaments in the
cylindrical strand form. Thus, fluid stream impingement at the time
of distribution aids subsequent dispersal treatments and the
filaments are more easily dispersable under the influence of the
liquid dispersing agent or binder because the bonding forces
holding the filaments in the normally cylindrical strand
configuration have been weakened. If the proper size or lubricant
is applied to the filaments as they are being attenuated and
combined into a strand, which size does not have strong bonding
ability, then sufficient filament dispersal may possibly be
effected by the jet or fluid stream or streams from the aerodynamic
diverting means impinging upon the strand for use in certain
products without further operations. However, since most
applications require a greater dispersal than that effected by the
aerodynamic diverting means, subsequent filament dispersal steps
may be employed as described hereinafter.
Referring to FIG. 2, a fluid supply line 16 is shown connected to
opposing nozzle means 100, 101 via control valves 17 and 18. The
control valves 17 and 18 may be regulated manually or, as shown, an
automatic control means 19 may be used to effect electrical
regulation of the valves to deliver a fluid stream from the nozzles
100, 101 to most effectively impinge the strands and disperse the
filaments to the degree desired. In addition, the control valves 17
and 18 and the control means 19 may be utilized to modulate the
flow of fluid from the nozzles 100, 101 to effect a sweeping
distribution of the strands across the collecting surface below.
Nozzles 102, 103 may be similarly controlled.
Referring to FIG. 3, there is illustrated apparatus for performing
subsequent filament dispersal steps in the novel method disclosed
herein. At a first liquid impingement station 70 a liquid 74 is
distributed evenly across the strand mat 60 by weir means 71. A
supply line 72 supplies liquid to the weir means 71. Valve means 73
may be utilized to control the flow of the liquid to the weir 71
and thus the amount of liquid impinging the strands in the mat 60.
The liquid 74 collects on a liquid retaining means 76 in a flooded
condition as noted at 75 to inundate the mat 60 either at the
impingement point, or at earlier or later points as desired. An end
plate 77 may be utilized to prevent the flood area 75 from flowing
to the left and off of the back of the liquid retaining plate 76.
If the liquid retaining plate 75 is slightly tilted and if the
conveyor 61 and mat 60 speed is sufficiently fast, the end plate 77
may not be required. Side plates 78, however, are required to
prevent a flow transverse to the direction of travel of the mat and
the stream formed by the flooded area 75. This insures that the
natural stream formed by the flooded area 75 will proceed to the
right side of the retaining plate 76 and pour over into catch basin
90. A sufficient flow is advantageously provided by regulating
valve 73 so that the flooded area 75 will become a stream moving at
substantially the same rate and in the same direction as the mat
60. This prevents any forward or reverse disruption of uniformly
distributed or oriented strands in the mat 60.
The most effective dispersal of the filaments of the strands within
the mat 60 may be effected by using a second liquid impingement
station 80. The second liquid impingement station 80 is spaced from
the first station 70 at a distance, depending upon the speed of the
conveyor 61, adapted to provide a predetermined soaking or bond
weakening interval. The second impingement station comprises a weir
81 supplied via supply line 82, which supply is controlled by valve
83. The control valve 83 in combination with the construction of
the forward lip 85 of the weir 81 combine to provide a
predetermined forward velocity of the impinging stream 84 with
respect to the mat 60 and the flood stream 75. It is desirable to
provide the impinging stream 84 with a slightly higher velocity
than that of the flood stream 75 and the mat 60, for most effective
dispersal.
Referring to FIG. 4, it will be noted that the lip of the weir 85
may be inclined, for example, 15.degree. from the horizontal, so
that in combination with the fluid control by the supply valve 83
the impinging stream 84 may be provided with a velocity in the
direction indicated by the arrow 84a. The weir means 81 is situated
sufficiently close to the surface of the flood stream 75 and the
mat 60 so that gravity will have little effect upon the direction
of travel of stream 84. As will be noted, the direction of travel
and speed of the stream 84 may be illustrated in vectorial form by
vectors 84b and 84c. It will be noted that the horizontal vector
84b is substantially greater than the downward vertical vector 84c,
thus insuring that the stream 84 will properly impinge the mat 60
and flooded area 75 to most effectively disperse the filaments from
the strands within mat 60.
After dispersement, the excess liquid may be removed from the mat
by two means. First, the liquid is allowed to drain through the
foraminous conveyor 61 into the catch basin 90 and is noted by
streams 91, which include both flow-through from the mat 60 and a
portion of the flood stream 75. By allowing the excess liquid to
drain vertically, the liquid will proceed toward holes or
interstices still left in the mat 60 thus carrying dispersed
filaments in such hole-seeking flow. This further disperses the
filaments and insures even smaller interstices and more uniformity
in the mat 60. The liquid material 91 from the catch basin 90 may
be removed via conduit 92 and pump 93. The conduit 92 and pump 93
may, if desired, be connected to recirculate the liquid into supply
conduits 72, 82. In a second liquid removal step, a suction chamber
110 having a suction opening 111 connected to a suitable air
exhaust system (not shown) may be situated beneath the foraminous
conveyor 61. As will be noted by the direction of the arrows
showing the vertically downward air flow, the filaments are held in
their dispersed position while further excess liquid is removed
from the mat.
Referring to FIG. 5, there is illustrated a front view of the weir
apparatus shown in FIG. 4, which apparatus may also be used for the
weir at station 70. The wier means 81 of FIG. 5 is connected with a
supply conduit 82 which supplies the liquid along the bottom 87 of
the weir means 81. A plurality of parallel vanes or baffles 86 have
been placed within the weir means 81 to insure that very little
side to side flow with respect to the travel of the mat issues from
the lip 85 of the weir 81 to disrupt the uniform distribution of
the strands. Baffle or vane means 86 are spaced from the bottom so
that liquid may be supplied to the entire weir means by a single
supply pipe 82. Thus a curtain or sheet of impinging liquid may be
supplied at either station 80 or at station 70 to the mat 60 and
the strand therein for filament dispersal.
It should be noted that the liquid for dispersement of filaments at
stations 70 and 80 may be simply water. It has been noted
hereinbefore, of course, that the impinging fluid stream from the
nozzles 100, 101, 102 and 103 may be gaseous or liquid. At the
stations 70 and 80, however, water may be used. It has been noted
that with some lubricants which are used to provide inter-fiber
mobility that the water may be made alkaline to aid dispersal. The
addition of a small amount of, for example, ammonium case-inate
will change the pH value of the water surrounding the strands from
acid to alkaline.
In addition to the use of plain water, or the alkaline water, it is
desirable to reopen the strands or to disperse the filaments by
using a liquid which is a solution containing the binder that will
eventually be used to integrate the mat. That is, a number of
aqueous solutions may be utilized which carry a binder which will
be deposited upon the filaments and strands and, after heat or
other treatment, will bind the filaments and strands together and
integrate the mat. Other forms of binders not in aqueous solutions
may, of course, also be used if there is sufficient liquidity to
provide a flooded area around the mat and the strands therein to
produce the dispersing effect from the soaking and/or impinging as
described hereinbefore.
There has thus been described and disclosed herein novel method and
means for dispersal of filaments from strands and the making of mat
products therefrom. Possible modifications and substitutions of
elements of the apparatus and method of this invention will occur
to those skilled in the art, and such obvious changes are
considered within the spirit and scope of this invention.
* * * * *