Note: Descriptions are shown in the official language in which they were submitted.
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METHOD FOR COLLECTlNG FIBERS FROM A ROTARY FIBERIZER
TECHNICAL FIELD
This invention relates to the forming of fibrous products from generally
5 long fibers. More particularly, the invention relates to a method for collecting fibers
centrifilged from a rotary fiberizer.
BACKGROUND OF ~VENTION
Fibrous m~teri~l which is used typically for acoustical or thermal insulation
is commonly formed by a rotary process. Molten material, such as glass, polymer material,
10 slag, rock or basalt, is placed into a rotating spinner having a peripheral wall with orifices.
The molten material is centrifuged through the orifices and formed into fibers. The fibers
are ~tteml~ted and directed d~wllw~ldly by the action of a fiow or blast of gases
discharged from an annular blower positioned circulllrerell~ially about the spinner. The
dowllw~dly moving swirling fiow of fibers and gases is referred to as the veil. The fibers
15 can be sprayed with a binder which adhesively binds the fibers together at their contact
points, or the fibers can be m~mlf~ctllred without binder. The fibers are then collected to
form a fibrous product or blanket.
A typical method of collecting the fibers incllldes a large hood with suction
devices, such as fans, sit~1~te~ underneath. The fibers are collected on a rOl~l~illOUS
20 conveyor positioned above the suction fans so that the suction force draws the fibers onto
the conveyor. For the production of long fibers the fibers should be collected within a
relatively short distance lln~1~rne~ttl the spinner, preferably within the range of from about
0.1 m to about 1.5 m. Lf the fibers are not collected close to the spinner the long fibers
tend to bunch together and form generally parallel groupings of fibers, referred to as
25 "ropes". This roping effect is undesirable because of the formation of a non-uniform
fibrous product having areas of high density and areas of low density. For the purposes of
this specification and claims, the term "long fibers" means fibers that are generally longer
than about 10 inches (25 cm) as measured by the drape length method.
Ideally, the long fibers should be collected without suction or with very low
30 amounts of suction to ",~il"~i n high loft in the fibers. High amounts of suction colllplt;ss
the fibers and reduce the overall recovery thickness of the insulation product. However, if
the fibers are collected close to the spinner on a fiat rol~llinous collveyor with low
suction, a large amount of fiber m~teri~l is blown away from the conveyor and is not
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collected. Also, the use of suction devices is undesirable because of the high levels of
noise produced, and because of the expense involved.
Another method of collecting long fibers is to use a direct formed process.
The fibers are captured by two opposed collv~yor sllrf~ces The collv~yor sllrf~ces are
5 angled dowllw~ldly inwardly to collect and consolidate the dowllw~ldly moving veil of
fibers and convert it into a flattened cross-sectional shape. The gases from the annular
blower are suctioned through the conveyor surfaces, which are rol~n~ ous. The conveyor
surfaces are operated in a d~wllw~ld direction to convey the fibers onto a second
collv~yor to form the fibrous insulation product. High amounts of suction are used to
10 capture the long fibers and substantially prevent the fibers from being blown away from the
conveyor and not collected.
It would be desirable to have a method of forrning and collecting long fibers
without the use of high suction so as to prevent the undesirable compression of the long
fibers, and to produce a fibrous product that is of uniform density.
DISCLOSURE OF INVENTION
There has now been invented an improved method of forming and
collecting long fibers to produce a generally uniform fibrous product. The method of the
present invention for collecting the long fibers inçllldes intercepting the fibers on a narrow
collector so that the fibers are draped over both sides of the collector, and then raising the
20 two sides of the draped fibers to form a generally planar blanket after the collector and
draped fibers have been removed from the dowllw~-dly moving gaseous blast. A narrow
collector is one which has a width that is substantially smaller than the diameter of the
spinner and the rli~met~r of the corresponding veil. The invention does not require the use
of suction devices which can damage the fibers and lower the recovery height of the
25 fibrous product.
Molten m~tP.ri~l is introduced into a rotating spinner which has a peripheral
wall having a plurality of orifices. The molten material is centrifuged through the orifices
to create generally long fibers where the fibers are directed generally dowllw~dly away
from the spinner. The fibers are intercepted on a collector so that the fibers are draped
30 over the collector. Preferably, the fibers are intercepted at a distance beneath the spinner
within the range of from about 0.1 m to about 1.5 m. The intercepted fibers form first and
second portions which are suspended over the collector and are oriented generally
vertically. The collector and intercepted fibers are then moved away from the spinner.
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The first and second portions of the suspended fibers are raised to a generally horizontal
ori~nt~tion~ thereby producing a generally planar fibrous product. The long fibers are
preferably intercepted without the use of suction devices for collecting the fibers, which
can damage the recovery height of the fibrous product. Preferably, the long fibers have an
5 average length which exceeds 10 inches (25 cm). The fibers can be m~nllf~ctured with or
without a binder applied to the fibers. The fibers can also be formed from various
m~teri~l~, such as glass or polymer m~t~ri~ . The spinner can also be adapted to form bi-
component fibers which are formed from two di~t;relll molten m~t~ri~ having di~elenl
coefficients of thermal expansion which cause the fiber to curl when cooled. Bi-
10 component fibers have high loft and greater entangl~m~nt charact~ri~tics when comparedto conventional straight fibers.
In a specific embodiment of the invention, the fibers are intercepted on a
foldable conveyor. The collv~yor is directed und~rneat~ the spinner in a folded position
with the first and second surfaces of the conveyor both oriented generally vertically so that
15 the intercepted fibers are draped over the conveyor. The conveyor and intercepted fibers
are then moved away from the spinner. The conveyor is then unfolded so that the first and
second surfaces are oriented generally parallel to each other and form a generally
horizontal surface, thereby producing a generally planar fibrous product. Preferably, the
fibers are intercepted on the conveyor without the use of suction devices. The width of
20 the conveyor in the unfolded orientation is greater than the width of the conveyor in the
folded orientation, preferably at least 5 times greater, and more preferably at least 10 times
greater. In another specific embodiment of the invention the fibers are collected on a
single beam.
BRIEF DESCRIPTION OF DRAWINGS
Fig. 1 is a schematic, partially sectioned, elevational view of a fiberizer
showing a prior art centrifuging process.
Fig. 2 is a schematic, partially sectioned, elevational view showing the
collection of fibers on a foldable conveyor of the present invention.
Fig. 3 is a schematic sectional view taken along lines 3-3 of Fig. 2 showing
30 the conveyor in the folded orientation with the suspended fibers draped over the collvt;yor.
Fig. 4 is a schematic sectional view taken along lines 4-4 of Fig. 2 showing
the conveyor in the unfolded orientation.
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Fig. 5 is cross-sectional view of the conveyor similar to that shown in Fig.
2, but having hollowed out portions for suction.
Fig. 6 is a st~hem~tiç~ partially sectioned, elevational view showing an
alternate embodiment of intercepting the fibers with a single beam collector and a ramping
5 member.
Fig. 7 is a schem~tic sectional view taken along lines 7-7 of Fig. 6 showing
the fibers collected on the single beam collector.
Fig. 8 is a schem~tic sectional view taken along lines 8-8 of Fig. 6 showing
the ramping member raising the fibers.
Fig. 9 is schematic representation of suspended fibers collected on a rod
using the drape length method for me~.cllring fiber lengths.
BEST MODE FOR CARRYING OUT THE INVENTION
Fig. 1 illustrates a conventional method of forming fibers by the use of a
fiberizer, generally indicated at 10. The fiberizer includes a rotating spinner 12 having a
15 peripheral wall 14 with a plurality of orifices 16. Molten material 18 is introduced into the
rotating spinner as a stream 19 and is centrifuged through the orifices forming fibers 20.
The molten m~t~ l can be of any material suitable for the formation of fibrous products.
The material can be inorganic, such as glass, rock, slag or basalt, or can be organic, such
as polymer material. The fibers e~ from the spinner are ~tt~nll~te~l and directed
20 d~wllw~d by the action of a d~wllw~d fiow or blast of gases 22 discharged from an
annular blower 24. The blower is positioned circull~t;lellLially about the spinner and the
gases are discharged from the blower at high velocity to turn the direction of the fibers
dowllw~.l, and in some cases to further ~tteml~te the fibers. The gaseous blast forms a
veil 25 which is a generally dowllw~dly moving column of swirling gases and fibers.
In a conventional process, the fibers are collected or intercepted on a flat
rOl ~lmllous conveyor surface 26 to form a continuous fibrous product, or blanket 28. It
should be understood that the rotary fiberizer method of forming fibers can be used to
form products other than a fibrous blanket, such as leil~olced products. Of course,
multiple fiberizers can be used in cooperation with each other to form a single fibrous
30 blanket. The veil is typically drawn towards the rol~l~inous conveyor by a strong suction
force which can be created by various suction devices (not shown), such as a fan. Without
suction, a substantial portion of the fibers would defiect or bounce off the conveyor
surface and not be collected.
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By controlling the speed of the rotating spinner, the velocity of the gaseous
blast from the blower, and the distance from the blower to the spinner, and other factors
controlling the fiber forming ellv.,.,nment, the length ofthe fibers can be altered to form
relatively short or long fibers. Preferably, the long fibers are bi-component fibers. Bi-
5 component fibers are formed from two di~el~;llL types of molten m~t~ri~l, each havingdi~Terelll coeffficients of thermal expansion so that the fiber curls when cooled. Long
fibers, however, tend to bunch together in the veil before being collected. The long fibers
sporadically form generally parallel groupings of fibers, referred to as ropes 30. This
roping effect is undesirable because of the formation of a non-unirollll fibrous blanket
10 which has areas of high density and low ins~ ting qualities, as well as unpleasant
aesthetics. The farther the fibers are collected away from the from the spinner, the more
likely roping will occur. The distance from the spinner 12 to the collection surface 26 is
indicated in Fig. 1 as distance "d". For shorter distances d, the suction force is increased
to draw the fibers onto the collv~yor surface before they are deflected off. However, high
l S amounts of suction compress the fibers and reduce the overall recovery thickness of the
fibrous blanket.
For the purposes of this specification and claims, the term "long fibers"
means fibers that are generally longer than about 10 inches (25 cm) as measured by the
drape length method. The drape length method measures fiber length by me~llring
20 the length of fibers collected on a narrow collecting rod, typically 0.25 inch (0.64 cm) in
diameter. The rod is moved horizontally with a smooth and swift motion through the
entire veil, thereby ca~Luling or collecting fibers on the rod. The rod should be moved
through the veil near the spinner to avoid "roped" collections of fibers. The distance from
the spinner depends upon various factors, such as, the molten material being fiberized and
25 the spinner diameter. For a 15 inch (38 cm) spinner for fiberglass, the rod is preferably at
a distance of about 9 inches (23 cm) from the spinner bottom. The suspended fibers will
span across the length of the rod at a (li.st~nce approxilllately equal to the veil diameter.
Fig. 9 illustrates a typical collection of fibers suspended from a collection
rod 70 used in the drape length method, where 71 is the approximate width of the veil.
30 With the rod held level, the average fiber drape length is measured by placing a tape
measure 73, or other measuring device, next to the rod and the general appearance of the
average length of the suspended fibers by sight is recorded. The general appearance of
the average length is represented by line 74 in Fig. 9. Regions 72 on the rod that are
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clearly inconsistent with the rest of the fiber lengths collected on the rod are neglected.
These incon~iit~nt regions are typically at the ends of the span of collected fibers where
the rod travels through a larger mllltitll~e of fibers in the veil. The procedure can be
repeated with a cleaned rod, especially if the fiber drape lengths are difficult to read. If
5 multiple readings are taken, the readings are then averaged to ~let~rmine the fiber drape
length.
Figs. 2 and 3 illustrate a prt;~l-ed embodiment of the present invention
using the same type of fiberizer 10, but with the long fibers being collected near the
spinner 12 on a narrow collector, such as a foldable conveyor 32. The conveyor 32 has
10 first and second surfaces, such as flaps 34 and 36 which are pivotally attached to the
conv~yor. The flaps are attached at a central portion 38 ofthe conveyor.
The section of the co~veyor which is lm(lerne~tl~ the spinner has the flaps
34 and 36 oriented generally vertically, and the section ofthe conveyor is said to be in a
folded position. The long fibers 20 move dowllw~d from the spinner and are collected by
15 the conveyor by being draped over the central portion 38 ofthe conveyor. The collection
of draped or suspended long fibers has an inverted U-shaped cross-section, as seen in Fig.
3. The fibers are not deflected or blown offthe collveyur because most of the high
velocity discharged gases from the blower 24 are directed around the conveyor flaps while
the long fibers are caught or collected on the central portion 38. Although a portion of the
20 fibers will not be collected, the majority of the fibers will form into a collection or mass by
their own entanglement and will drape over the conveyor.
Because the gases ofthe dowllw~dly moving gaseous blast are directed
around the conveyor, the central portion 38 ofthe collv~yor can be positioned subst~nti~lly
closer to the spinner than a flat collector could be. The conveyor of the present invention
25 can be used without suction devices, or used with low amounts of suction to help reduce
the amount of deflected fibers. Since high suction compresses and breaks the long fibers,
the recovery height of the fibers collected by the present invention is not greatly affected
due to the absence of high suction. Because of the ability to collect the long fibers near
the spinner, the formation of bunched groupings of long fibers or ropes is greatly reduced.
30 Preferably, the distance d is within the range of from about 0.1 m to about 1.5 m.
As the collv~yor moves in a direction 40 away from the veil and the
dowllw~ldly moving gaseous blast, the conveyor unfolds so that the flaps 34 and 36 are
oriented generally parallel to each other so that they form a generally hori~ont~l plane or
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sllrf~ce, as can be seen from Fig. 4. The flaps lift the draped or suspended long fibers and
orient them to form a generally planar fibrous blanket. If desired, the continuous fibrous
blanket can then be cut on the edges for a consistent and uniform width. The collveyor
flaps can be lifted up in any suitable manner such as by traveling on a ramp (not shown) or
5 lif :ed by ~rm~tllres (not shown). The collv~;yor can be any sllfficient surface which can be
folded and unfolded, such as a plurality of hinged sections, wire mesh, nylon webl)ing or a
covering of fiexible material.
As seen in Figs. 3 and 4, the horizontal width W of the conveyor in its
folded position is sufficiently shorter than the horizontal width W' ofthe conveyor in its
10 unfolded position. The unfolded width W' ofthe conveyor is preferably greater than about
5 times the width W of the conveyor in the folded orientation so that the gaseous blast can
be directed around the flaps. The closer the widths W and W' are to each other, the more
the foldable conveyor performs like a conventional flat conveyor having the problems of
fiber deflection.
Fig. 5 illustrates an embodiment of the conveyor 32 which is adapted to
provide for low suction to draw the fibers onto the conveyor. The flaps 34 and 36 are
hollowed out with a plurality of orifices 42 in outside sllrf~ces 34a and 36a ofthe flaps,
respectively. Tubing 44 communicates with the hollowed out portion of the flaps and a
suction device (not shown) to provide for suction to draw stray fibers onto the outside
20 surfaces of the fiaps. A low amount of suction force is preferable to m~int~in the high loft
in the fibers. High suction will damage the fibers and reduce the overall recovery
thickness.
Although the narrow collector has been described as a foldable conveyor,
the collector can be any sufficient collecting surface which is narrow enough to allow
25 passage of most of the discharged gases. Fig. 6 illustrates another embodiment of the
invention in which the narrow collector is a single beam, s~l~em~tically shown as 50. The
beam can be of any suitable material or shape which is narrow enough to intercept the long
fibers and allow the blast of gases 22 to flow around it. The beam moves in the direction
40 away from the gaseous blast and collects the long fibers 20 in the same manner as
30 collector 32 by intercepting the long fibers so that the long fibers drape over the beam. As
shown in Fig. 7, the suspended fibers form first and second portions 52 and 54 which are
oriented generally vertically. The beam carrying the fibers then travels in the direction 40
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away from the gaseous blast and veil, and between two opposed ramped members,
illustrated as ramp conveyors 56.
The ramp COllv~yOl~ have an end 58 which is positioned generally
vertically, and an opposing end 60 which is positioned generally holi~ollL~lly. The ramp
5 conveyor has a surface 62 which extends from the vertical end 58 to the hori~ont~l end 60
in a twisted configuration. The resulting shape of the surface 62 is much like a fiat sheet
which has one end twisted or turned 90 degrees with respect to the other end. The surface
62 of the ramp conveyor is moving in the direction 40 at apploxilllalely the same speed as
the beam. As the beam moves between the ramp conveyors, the first and second fiber
10 portions 52 and 54 contact their respective ramp surfaces 62 at the vertical end 58 ofthe
ramp conveyors 56. The fiber portions are then propelled in the direction 40 by the ramp
conveyor and the beam, and ~imlllt~neously raised upward by the rising surface ofthe
ramp conveyor, as can be seen in Fig. 8. Eventually, the beam is directed away from the
fibers and the first and second portions are lying solely on the sl~ ces of their respective
15 ramp CO11V~;YO1~. When the first and second portions 52 and 54 of the fibers are lying on
the hol;~o"l~l end ofthe conveyor, the portions are oriented in a generally holiGonLal
position, thereby forming a generally planar fibrous blanket 28. The continuously forming
blanket is transported away by a take away collv~yor 64.
It can be advantageous to have the collector be separate from the ramping
20 member because the collector intercepts the fibers in the harsh ellvholllllent of the veil.
The embodiment with conveyor 32, as shown in Fig. 2, combines the functions of the
collector and the ramp into one structure. The collector is preferably constructed from
durable m~t~ because the gases and fibers can be at very high temperatures. However,
the ramp member, such as the ramp CO11V~;Y(J1~ 56 which are separated from the single
25 beam collector 50, is not subjected to the harsh veil environment and can be constructed
from conventional, less durable materials. Also, cleaning of the collector 32 may be
required after each pass through the veil, whereas the ramp conveyors 56 may not require
cleaning as frequently.
Although the ramp member is illustrated as ramp COllv~yOl~ 56, the ramp
30 member can be any apparatus which is suitable for raising the first and second fiber
portions 52 and 54 to a horizontal orientation. For example, stationary ramps (not shown)
could be used. The stationary ramps would be shaped similar to ramp conveyors 56 in a
twisted-like configuration. The surface of the stationary ramps could be made out of low
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frictional material or adapted with air ~ ting features to ~ "i~e the frictional dragging
force. Vents on the surface of the stationary conveyor could provide for a cushion of air
for the rolw~ldly moving fibers to travel upon. The vents could even be shaped so as to
direct the air in the r,,l w~d direction 40 to assist in moving the fibers.
It is to be understood that the first and second portions of the blanket can
remain folded, and can be removed from the collector, and packaged in a folded manner,
whereby the end user unfolds the blanket for init~ tion
It will be evident from the foregoing that various modifications can be made
to this invention. Such, however, are considered as being within the scope of the
10 invention.
INDUSTRIAL APPLICABILITY
The invention can be useful in the m~mlf~cturing of fibrous insulation and
filtration products.
