Note: Descriptions are shown in the official language in which they were submitted.
; ~
The present application i5 a di.v.tsion of our
copending application Serial No. 290,246, filed November
4, 1977.
Fiber formation from.attenuable material by esta-
blishing a pair of counter rotating whirls or tornadoes,
known as toration, is disclosed in our Canadian Application
No. 196,097. In that known technique, a gaseous blast
is generated and a gaseous jet, known as secondary or
carrier jet, is also generated, the jet being of smaller
cross section than the blast, being directed in a path
transverse to the axis of the blast, and having higher
kinetic ener~y per unit of volume than the blast so that
the jet penetrates the blast. Such a jet penetrating a
blast develops a zone of interaction of the jet and blast~
which zone is characterized by the development of a pair
of opposit~ly rotating tornadoes between which a zone of :
relatively low pressure occurs at the blast boundary adja~
cent to and downstream of the zone of penetration of the ~-
jet into the blast. In this known toration technique t
a stream of the attenuable material is delivered to the
zone of low pressure, from which the attenuable material
en~ers the zone of interaction between the jet and blast
and is subjected to the high velocity currents of the
whirls or tornadoes, thereby effecting attenuation of the
stream and forming the flber.
`, `,,~ ~ ~ . , :
~. .
.
~L~519 ~
As disclosed in the prior application above re-
ferred tc~ the stream of attenuable material is delivered
or introduced into the zone of interaction by the placement
of a discharge orifice for the attenuable material at or
substantially at the boundary of the blast. It is a major
objective of the present invention to provide for the sep-
aration of the discharge orifice for the attenuable material
from the boundary of the blast and at the same time to
provide for such separation while maintaining stable deliv-
ery of the attenuable material into the system. The manner
in which this is accomplished will be developed more fully
herebelow.
In accordance with one important aspect of the
present invention, provision is made for the generation
of a pair of counter-rotating whirls or tornadoes, by estab-
lishing a gaseous flow or jet and by utilizing certain
jet guiding structure or deflector arranged (in the manner
more fully described hereinafter) to generate a pair of
counter-rotating whirls or tornadoes having therebetween
an area of substantially laminar flow also characteriz~d
by low pressure with consequent pronounced induction of
air. It will be noted that, in accordance with this aspect
of the present invention, the pair of counter-rotating
tornadoes is generated by guide structure influencing a
gaseous flow or jet, rather than by the penetration of ~--
a jet into a blast, as in the toration technique disclosed ~;
in the application above identified. The action of the
--2
. ~1~1~
deflector not only develops the pair of tornadoes but also
provides the substantially ldminar flow low pressure area
between the pair of tornadoes, and the present invention
contemplates the introduckion or del~very of a stream of
attenuable material, for instance~ molten glass, into the
influence of the induced air entering the zone or area
of laminar flow formed between the pair of counter-rotating
tornadoes. This results in introduction of the stream
of attenuable material into the laminar flow between the
tornadoes and thence into the inEluence of the high velocity
currents of the pair of tornadoes, with consequent atten-
uation of the stream to form a fiber.
In accordance with another important aspect of
the present invention~ the a-ttenuation technique above
described, including the generation of the oppositely rotat-
ing tornadoes acting on a gaseous jet is used as a first ~-
stage of a two-staye attenuation technique, the second
stage being effected by delivery oE the jet a~d the atten-
uating fiber carried thereby transversely into a blast
of larger cross section, the jet still retaining sufficient
kinetic energy to penetrate the blast and develop a zone
of interaction in accordance with the toration technique ~-
describe~ in the above identified applications. This re-
sults in in~roduction of the pre]iminarily attenuated fiber
into the zone o-f interaction of the jet and the blast,
with consequent further attenuation of the fiber.
By the above described operation, a single fiber
is formed from a single-stream of the attenuable material,
notwithstanding the fact that the stream is subjected to
two sequential stages of attenuation/ each of which in-
volves the subjection of a stream or fiber to the action
of the high velocity currents set up by the two sequential
pairs of tornadoes generated in the jet and in the blast.
Employment of the technique according to the
invention, has numerous distinctive advantages. In the
ln first place, from the foregoing it will be seen that the
use of the pair of tornadoes developed by jet guiding means
as a first stage of the attenuating operation, serves also
as a means for introduction of the attenuating fiber into
the zone of interaction between the jet and the blast,
i.e. into the torating zone. Thus, this first stage is
in effect utilized as a feed or delivery means in relation
to the toration operation subsequently carried on in the
toration zone between the jet and blast. This use of the ~;
first stage has numerous important advantages. In the
first place such use makes it possible for substantial
separation of the several components of the system, namely
th~ means for generating the blast, the means for generat- ;
ing the jet and the means for introducing or delivering
the attenuable material into the system.
'
Separation of the components is in turn advan-
eageous for a number of reasons including particularly
the fact that such separation reduces heat transfer between
. .
:
~,1
the three components of the sys~em, in view of which greater
flexibility is possible in the maintenance of different
temperatures as between the means for generating the blast,
the rneans for generating the jet and thé means for sup-
plying and admitting the attenuable material. In turn,such reduction in heat transfer between these components
makes possible the use of the system for the production
of fibers from materials, such as hard glasses, which
require relatively high temperatures to bring them to the
molten state or consistency appropriate for a~tenuation.
The separation of the components which is made
possible according to the present invention, also elimi-
nates or reduces the production of unfiberized or improp-
erly fiberized particles resulting from sticking of the
attenuable material on hot surfaces. In consequence, more
uniformly fiberized products are obtainable.
Still further, the employment of the two-stage
system of the present invention, in which the first stage
serves as a means for feeding the attenuable material into
the zone of interaction of the jet and blastJ i.e~ the
toration zone, is desirable because it provides a means
for stabilizing feed of the attenuable material into the
zone of interaction, notwithstanding the substantial separa-
tion of the supply means for the attenuable material from
th~ boundary of the blast. Indeed, even with quite sub-
stantial separation, the feed of the attenuable material
~ ~: , . . . . .
~ 1~;~5~9
i3 stabilized and accurately controlled, which is an impor-
tant factor in providing for uniform fiberizing in t~e
zone of interaction, i.e. for uniform tora~ion. Because
the first stage or Eeeding means utilizes a pair of counter-
rotating tornadoes generated in spaced relation by theguiding action of elements positioned to influence the
jet, the laminar flow low pressure area between the tor~
nadoes into which the attenuable material is delivered,
results in accurate feed of the stream of attenuable mate~
rial from that area into the region between the counter-
rotating tornadoes, and this accuracy is maintained even
in the event of some misalignment of the supply orifice
for the attenuable material with relation to the jet.
' :;,
In consequence of this "automatic" compensation ~ ;
for inaccuracies in the point of supply of the attenuable
material, hiyh precision machining of certain parts is
no longer necessary, for instance parts associated with
the feed of a stream of molten glass~ Such high precision
of machining is not readily compatible with the very high
temperatures encountered in the handling of molten glass,
and this is particularly so where very hard glasses or
certain other materials such as slags or certain rocks
are being fiberized.
,,: ~...
It is also noted that as an alternative, a slot
may be employed for admission of the attenuable material
in the general manner disclosed in Figures 12 and 12~,
--6
L3~5i~
of the prior ~anadian application above re~erred to in
which event, supplem2ntary secondary jet9 would be located
one beyond each end of the slot.
The technique of the present invention is also
of advantage because it may be employed in connection with
a wide variety of attenuable materials, includin~ not onl~
various mineral materials as mentioned above, but even
certain organic materials which may be attenuable, sùch
as polystyrene, polypropylene, polycarbonate and polyamides.
In the two-stage attenuation tech~ique above
referred to, the invention also contemplates employment
of certain novel interrelated conditions oE operation of -~
the gaseous jet and gaseous blast, providing improved
efficiency with respect to power or energy consumption~ ~
Thus, the invention contemplates establishment or a tor-- ;
ating zone of interaction between the jet and blast by
employment of lower jet velocities and temperatures than
heretofore used in establishing the ~one of interaction
between a jet and blast. By employing lower jet tempera-
tures (for instance a temperature approximating ambient ;
or room temperature), consumption of energ~ to heat the
jet is eliminated and, in addition, the gas of the jet
is increased in density. In consequence, the kinetic
ener~y level of the jet required for penetration of the
jet into the blast is provided at lower jet velociti~s,
-7-
51~
thereby effecting further power economies. When employing
such lower jet temperatu~es r ~`,t lS, even pos~ible to employ
jet velocities well below the vel~city of the blast and
still maintain the kinetic energy level of the jet suf-
ficiently high to provide the des:ired penetration of thejet into the blast.
The lower jet velocities are still fur~her of
advantage in the two-stage attenuation technique herein
disclosed because in the first stage of attenuation, in
which the st~eam o~ attenuable material is delivered to
the jet, the lower jet velocities and temperatures assist
in avoiding fragmentation of the stream of attenuable
material.
Although, for most purposes, it is conte~.plated
according to the technique of the present invention, that
the fiberization of the attenuable material be effected
in two stayes in the manner generally descxib.d above,
it is to be noted that for some purposes the attenuable ;~
material may be subjected to only the firs-t stage of the
fiberiæation described, i.e. may be subjected to only that
stage of the fiber.ization occurring as a result of the
feed of the attenuable material into the zone between the
counter-rotating tornadoes developed by the action of guide
elements employed with the jet. In this event, the blastr .-
i.e., the toratiny blast, and the penetration of the jet
into the blast may be dispensed with, thereby simpli~ying
the e~uipment set: up~
.~
-8- ~
19
Although the technique o~ the present invention
is applicable to any attenuable material, it i5 particularly
adapted to the attenu~ation~o~ thermoplastic materials and
especially thermoplastic mineral materials such as glass
~nd similar compositions which are heated to the molten
state or the mol~en consistency appropriate for attenuation.
The embodiment illustrated and described hereinafter is
particularly appropriate for use in the attenuation of
~lass or similar compositions, and where references are
made to glass, unless otherwise indicated by the ~ontext,
i~ is to be understood that any appropriate attenuable
material may be used.
The invention claimed in the parent application
above identi~ied, provides a method for forming fibers
from attenuable material, comprising generating a gaseous
jet having a substantially laminar Çlow central portion
and having at opposite lateral sides a pair of counter-
rotating tornadoes of diameter progressively increasing
and ultimately merging downstream of the portion of laminaL
flow, and delivering a stream of attenuahle material to
the portion of laminar 10w between the tornadoes upstream
of the region of merging.
The invention claimed in the parent application
may be carried out by an apparatus for forming fibers from
attenuable material comprising means for genexating a gaseous
flow, means for establishing a pair o spaced counter~rotating
:; . . ~ ... ~: , .
3l1;~5~
tornadoes and an interilled1ate la~inar flow area irl the
gaseous 10w with the laimillaL fl~w area exposed at one
side of the gaseous flow and with the tornadoes increasing
in diameter and ultimately merging downstream of the laminar
area, and means for delivering a stream of attenuable material
into the influence of the gaseous flow in a region along
the path thereof in the exposed laminar flow area between
the tornadoes.
In accordance with one aspect as claimed in the
present application, the invention provides a method for
converting molten glass into glass fibers comprising deliv-
ering a stream of the molten glass downwardly from ~ supply
orifice, establishing a gaseous blast spaced below the
glass supply orifice, developing a gaseous jet of smaller
cross section than that of the blast directed in a path
toward the glass stream between the glass supply orifice
and the blast, and deflecting the jet from said path into
a patb extended downwardly toward the blast by interposiny
a deflector element between the jet and the glass stream,
the glass stream being delivered to the deflected jetO
,; : '
In accordance with another aspect o~ the invention ~ :
as claimed herein, there is provided equipment for making
fibers from attenuable material comprising supply means
for the attenuable material having a delivery orifice posi~
tioned for downward delivery of a stream of the material,
'
--10--
:., ;,
,
5~9
,
means for establishing a gaseous blast ~elow the supply
means, means for establishins a gaseous jet including an
orifice discharging a Jet of smaller cross section than
tbat of the blast, and means for deflecting the path of
the jet into a path intersecting the path of the blast,
the delivery orifice for the attenuable material being
positioned to deliver said stre~n to the jet in said de-
flected path, the de~lected jet being oE sufficient velo-
city to penetrate the blast and develop a zone of interac-
tion of the jet and blast in the vicinity of the penetration
of the jet.
Equipment is also provided comprising supply
means for the attenuable material having a delivery orifice
positioned for downward delivery of a stream of the mate-
rial, means for establishing a gaseous blast in a position
spaced below the supply means, means for establishing a
gaseous jet including an orifice discharging a jet of smaller
cross section than that of the blast, and jet guiding means
comprising a guide element positioned to guide the jet
in a path from which the jet approaches and penetrates
the blast through the boundary thereof presented toward :
the stream delivery oxifice and thereby develop a zone
of interaction of the jet with the blast~ said delivery
orifice being positioned with relation to the jet and blast
~o deliver the stream of attenuable material to the influ- ;
ence of the guided jet and thence into said zone of interaction~ ~ -
:'
; . -
519
S~ill further, in ar.other aspect, there is provided
., , ', r ~. .
equipment for making ~l~ss f bers from molten glass compris-
ing glass supply means having a delivery orifice positioned
for downward del.ivery of a stream of molten glass, means
for establishing a gaseous blast spaced below the glass
delivery orifice, means for establishing a gaseous jet
including an orifice discharging a jet of smaller cross
section than that of the blast, and jet guiding means com-
prising a guide element positioned to guide the jet in
at least a portion of a path between the jet orifice and
the boundary of the blast pres~nted toward the glass deliv-
ery orifice, the jet having kinetic eneryy per unit of
volume higher than the blast and penetrating the blast
to develop a zone of interaction of the jet with the blast,
and the glass delivery orifice being positioned with rela-
tion to the jet and the blast so that the stream of molten
glass is introduced into the influence of the guided jet
and thence into said zone of interaction~ ~ :
The invention as claimed herein also provides
equipment for making glass fibers from molten glass com- ~:
prising glass supply means having delivery orifices posi-
tioned for downward delivery of streams of molten glass,
means for establishing a gaseous blast spaced below the ~:
glass delivery orifices, means for establishing a plural-
ity of gaseous jets including orifices discharging jets
of smaller cross section than that of the blast, and jet
-12- .
~3V5~g
~y
guiiding meians comprising a guidi~i element interposed ini
part in the path of the ~ett~ind positioned to guide the
jets in at least a portion of the path thereof between
the jet orifices and the bou~dary of the blast presented
toward the glass deIivery orifices, the jets being o~ higher
velocity than t~ej blast and penetrating the blast to develo~
zones of interaction of the jets with the blast, the jets
being p~sitioned close to each other to provide for inter-
action t ~ eof in their guided paths, and the glass delivery
orifices being positioned with relation to the jets and
the blast so that the streams of molten glass are introdllced
into the influence of the guided jets and thence into said
zones of interaction.
The apparatus as claimed herein also comprises
lS means for establishing a gaseous blast, a series of spaced
orifices for directing gaseous jet.s in side-by-sid~ gener~illy
parallel paths and peinetrating the blast to de~elop æones
of interaction between tihe jets and the blast, means for
delivering stre~ms of molten attenuable material ir=ito the
influence of said zones of interaction including a supply
bushing having a series of delivery orifices for the molten
material, gas supply means fo~ the jet orifices comprising
separate manifold boxes for different groups of the jet
orifices r and means for mounting the manifold boxes for
separate adjustrrient movement with respect to the streams ~ -
of the molten attenuable material.
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,,. ~ `
, . .
s
How the roregoin~.features and advantages are
attained will appear more fully from the following descrip-
tion referring to the accompanying drawi.ngs which illus~
trate one preferred embodiment of equipment according to
S the invention and also which diagrammatically represent
significant portions of the acti.on of the jet, blast and
of the attenuating operation itself. In the drawings ~
FigurP 1 is an outline overall elevatio~al view
with a few parts shown in vertical section showing the
general arrangement of the major components of an e~uipment
according to the technique of the present invent.ion;
Figure 2 is an enlarged vertical sectional view
of the components provided at one of the fiberizin~ centers,
this view being taken as indicated by the section line
2-2 on Figure 4;
Figure 3 is a further enlarged ~ragmentary in-
verted plan view of some of the jet and glass orifices,
this view being taken as indicated by the line 3-3 on
Figure 25
Figure 4 is an elevational view of portions of
the equipment shown in Figures 1 and 2 and taken from the
right of Figure 2;
-14-
i9
Figure S is a plan view taken ~enerally ~s in-
dicated by the line 5-5 applie~ to ~igu~e 4;
Figure 6 is an enlarged perspective view of a
jet manifold box employed in the equipment shown in Figures
1 to 5;
Figure 7 is a perspective diagrammatic view il-
lustrating the operation of the method and equipment according
to the present invention;
Figure 8 is a cross sectional fragmentary and
enlarged view oE the equipment viewed as in Figure 2, and
illustrating certain phases of the activity of the blast
and jet in ef~ecting attenuation of the glass being delivered
from the orifice at the top of the figure;
Figure 9 is a plan view of several jets and of
portions of the blast shown in Figure 8, but omitting the
glass feed and glass fibers being formed;
Figure 10 is a transverse diagram through por-
tions of several adjacent jets, and illustrating directions
of rotation o~ certain pairs of the counter-rotating tor- ::
20 : nadoes;
:~;
Figure 11 is a fragmentary sectional view of
the major components, particula~ly illustrating certain
dimensions to be taken into account in establishing operating
conditions in accordance wi-th the preferred practice of
the present invention;
-15-
. .
.
Figure lla is a fragmentary sectional view show-
ing the spacing between a pair of adjacent ~et orifices;
and
Figure llb is a transverse sectional view through
a portion of the delivery means for the attenuable material.
In connection with the drawings, reference is
first made to Figure 1 which shows somewhat schematicall~
a typical overall arrangement ~f equiprnent adapted to carry
out the techni~ue of the present invention~ Toward the
left in Figure 1 there is shown in outline at 15 a portion
of a burner or blast producing structure having an associat-
ed noz21e 16 with a discharge aperture 17 of substantial
width so as to deliver a blast 1~ with which a plurality
of fiberizing centers may be associated. A supply line
for a saseous fluid under pressure is indicated in Figure
1 at 19 and this supply line is connected to jet manifold
boxes 20 which cooperate in supplying the jet fluid to
and through jet orifices, one of which appears at 21. ~ ~-
A bushing 22 associated with a forehearth or
other appropriate glass supply means indicated at 23 is .
provided with glass orifice means indicated at 24, and
the stream of glass is delivered into the flow of the jet ~:
to be described hereinafter and is carried downwardly to
the zone of interaction in the blast 18. As will be ex-
plained, fiberization occurs in the jet and also in the
' '
.,
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'
-16- :
.. ~
blas~, ~r~d as t~,e ~last de~.ivers the fibers toward the
right as viewed in ~igure l~;~a fiber blanke~ indicated
at 25 is laid down upon ~per~orated traveling conveyor
or belt 26, having a suctijon box 2.7 below the upper run
of the conv~yor, the box 27 connecting with a suction fan
diagrammatically i~ndicated at 28 to assi.st in laying down
the desired fiber blanket on the perforated conveyor 26~
Various of the fiberization parts are sho~n in
greater detail in Figures 2 to 6 inclusive, to which ref-
erence is now made.
The blast and jet structures are advantageouslyadjustably mounted with respect to supporting structure
such as diagrammatically indicated at ~9, so that the rela-
tive vextical positioning of the blast and the jet ma~
. 15 be altered, and preferably also so thàt the relative posi- ~
tioning of these parts may be adjusted in a direction up- ~;
stream and downstream of the blast 18.
As seen particularly in Figures 4 and 5f the
blast nozzle 16 is of substantial width r thereby providing ~;
2~ for a wide blast delivery orifice 17. The bushing 22 for
the supply of glass preferably also has substantial dimen~
sion in the direction perpendicular to the plane of Figure
2 in order to provide for the supply of glass to a multi- :
plicity of the glass delivery devices 24 as clearly appears
-17-
.. .~.~
~L3~5~L9
in Figure ~. Each of the delivery devices 24 has a m.eter-
ing orifice 24a and preferably also an elongated reservoir
or cup downstream of the metering orifice as indicated
at 24b (see particularly Figures 2 and 3). The reservoirs
or cups 24b are desirably elongated in the plane of the
fiberizing center, i.e. the plane containing the ylass.
supply device 24 and its associated jet orifice 21.
.The jet orifices 21 are provided in the front
edge wall of each of a series oE manifold boxes 20, four
such boxes being pro~ided in the equipment illustrated,
and these boxes are mounted by means of mounting rods,
including guide rods 30,30 mounted on the supporting struc-
ture 29 and which extend throughout the length of the bush-
ing 22 and which pass through apertures 31 (see Figure
2 and Figure 6) on the mounting lugs 32 provided at each ~;
end of each of the jet manifold boxes 20. Thus, the sev- '
eral jet manifold boxes are mounted with freedom for shift-
ing movement either to the right or left as viewed in Fig-
ures 4 and 5.
Z0 The positions of the jet boxes on the mounting
guide rods 30 are determined by means of additional rods -
33, 34, 35 and 36, each of which is threaded at its inner
end, to cooperate with a threaded aperture in one of the
lugs 32 of the guide boxes, one such threaded aperture
appearing at 37 in Figure 6. Each of the rods 33 to 36
-18-
,, . , : :
.. ~
r: ~
is provided with CL notchçc3 end 3~ by mean,s of which it
may be ~tated, and thesè!adjustable rods are axially
fixed, so that rotation thereof :imp~rt~ a lateral adjust-
.~ ',r ~ ~
ment or shiftin9 ~o ~ ~ to the associated jet manifold
5 box 20.
~y this arrangement, the relative positions of:
the ~et orifices 21 with respec~ to ~he glass orifice
devices 24 may be acljusted~ and this may be used to com
pensate for thermal ~xpansion and contractiorl of parts.
Havin~ the jet orifices distribu~ed ~etween cl number of
jet manifol~ b~x~s tfour in the embodiment illustrated)
provides fo~ substantial alignment of the jet orifice3
with the glass orifices on lirles paral~el.in~ the flow of
the blast. Al~hough tha alignment may not be absolute,
this is not necess-ary with equipment of the kincl herein
illustrated in which the glass stl-eams are delivered into
the substantially laminar flow zones ~etween the tornadoes,
such as 44b shown in Figure 7, since as above bcought out r
delivery of the glass streams into these ~orles re~ults
in automatic compensation for sl.ight inaccuracies in the .
~elative positions of the jet and glass orifices.
Each of the boxes 20 is conllected with the jet
~luld supply line 19 by means of a pair of flexible con- ~
nections 39 which permit adjustment of the pos.ition of ~ --
the boxes 20 ind~pen~ently of the supply line 19. ~ ~
19-- :
~ ;
As hereinabovelindicated, it is eontemplatec1
according to the present invention that the jets delivered
from the jet orifices 21 be su~je~ted to the ~uiding action
of certain ele~ents or devices which cooperate with the
jets in generating the desired pairs of counter-rotating
whirls or tornadoes which are utilized or at leas~ the
preliminary attenuation of the streams of attenuable mate-
rial and also for purposes of feed of the partially atten-
uated filaments into the zone of interaction provided by
lD penetration of the jets into the blast~ i.e. into the
toration zones. For the purpose of developing the counter~
rotating pairs of tornadoes, the present invention con-
templates the utilization of a guiding means, advantageously
a common deflector plate 40 associated ~ith a group of
the jet orifices. Where the jets are subdivided into
groups, and each group associated with a manifold box such
as indicated at 20, each such box des~irably carries a
deflector plate 40. As seen particuIarly in Figures 7
and 8, the guide or deflector plate is desirably formed
as a bent plate, one portion of which overlies and is
secured to the jet manifold box and the other portion of ~-
which has a free edge 41 lying in a position in the path
of flow or core of the jets delivered from the jet orifices
21, advantageously along a line intersecting the axes of
the jet orifices.
As is graphically illustrated, particularly in
Figure 7, this position of the deflector plate 40 and its
edge 41 results in impingement of each of the jets upon
-20-
9~3(~
the underside o~ the ~late 4~ ~ith conseguent spreading
of the jets. Thus, in Figure 7, the flow of four of the
jets originating from orifices a, b, c and d is shown,
and it will be seen that as the edge 41 of the plate is
- S approached, each of the jets spreads laterally.
It is contemplated according to the invention
that the jet orifices 21 be placed sufficiently close to
each other and also that the deflector or guiding means
be arranged so that upon lateral spreadiny~ the adjacent
or adjoining jets will impinge upon each other in the
region of the edge 41 of the deflector plate. Preferakly,
the adjacent jets impinge upon each other at or clo~e to
the ~ree edge 41 of the guide plate 40 as is shown in
Figure 7. This results in the generation of pairs of
counter-rotating whirls or tornadoes which are indicated
in Figure 7 in association with each of the three jets
delivered from the oriices a, b and c.
In analyzing he formation of these tornadoes,
particular reference is made to those associated with the
jet originating from orifice b in Figure ?~ Thus, it will
be seen that tornadoes 42b and 43b, are generated and that
these two tornadoes have their apices originating substan-
tially at the edge 41 of the deflector 40 at opposite sides
of the jet at the zone in which the spreading jet impinges
upon the adjacent spreadin~ jets delivered from orifices
-21-
a and o. The tornadoes 42b and 43b are ~ppositely rotating
as i5 indicated particularly in Figure 10, and the tor-
nadoes enlarge as they progress, until they meet at a poin~
spaced downstream frorn the edge 41 of the deflector. These
-5 tornadoes 42b and 43b also have currents in the downstream
direction, as will be seen.
Because of the spacing of the apices or points
of generation of the tornadoes 42k and 43b and because
o~ the progressive enlargement of those tornadoes t a gen-
erally tri~ngular zone 44b intervenes between the tornadoes
and the edge 41 of the deflector plate, and this triangular
zone is of relatively low pressure and is subjected to
extensive inflow of induced air, but the flow in this zone
is substantially laminar. This is the zone into which
the stream of molten glass or other attenuable material
is introduced into the system, and because of the character
of this triangular laminar ~one the stream of glass is
not fragmented but is advanced as a single attenuating
stream into the region between the pair of tornadoe~. ;
Attention is now called to the fact that the
directions of rotation of the currents in the tornadoes
42b and 43b are opposite, being clockwise for tornado 42b
and counter clockwise for tornado 43b as viewed in Figure
7. Thus, the currents in these two tornadoes approach
each other at the upper side thereof an~ then flow down~
wardly toward the central or laminar zone 44b.
-2~-
... ~
, . . . . . - . .. , " j,
The directions of rotation just referred to are
further indicated by arrows for the tornadoes 45a and 46a
in connection with the corresponding pair of tornadoes
associated with the jet delivered from the orifice a.
It will be understood that in the illustration of the jet
flow originating from orifice a~ t:he flow has been shown
as cut off or sectioned adjacent to the downstream end
of the zone of laminar flow 44a, i.e. adjacent to the zone
in which the pair of tornadoes have been enlarged and com~
mence the mutual merging which occurs as the jet flow pro-
ceeds. With the illustration just referred to, it further
clearly appears that the jet flow originating from orifice
a not only includes the pair of tornadoes 45a and 46a but
also includes another pair of tornadoes 47a and ~8a, the
directions of rotation of which are also opposite to each
- other, as shown ln Figures 7 and 10, but in this case,
the tornado ~7a at the left, as viewed in Figure 7, rotate~
in a counter clockwise direction, whereas the tornado ~8a
at the right rotates in the clockwise direction. It will
be understood that similar duplicate pairs of tornadoes
are generated by and associated with each of the jets.
The origin of generation of the lower pair is somewhat
different than the origin of generation of the upper pair ~;~
as will be explained hereinafter with more particular
reference to Figure 8.
Still referring to Figure 7, as the flow proceeds
from the plane in which the tornadoes are illustrated for
the jet delivered from orifice a, all four of the tornadoes ~ ;
''..
~,
-23-
tend to merge and; reform a more generalized jet flow and
this is indicated in Figure 7 by a section 49c, represent-
ing a downstream section of the jet Elow originating from
orifice c. As will be seen, the whirling motions of the
tornadoes are diminishing in intensity and the entire flow,
including the laminar flow of the central zone of the jet,
intermix with each other in the region indicated at 49c,
and thereafter the jet prog~esses downwardly toward the
blast which is indicated at 18 in Figure 7 and referred
to more fully hereinafter.
In the illustration of Figure 7 it will be under-
stood that for the sake of clarity, the showing of the
various portions of the jet flow is so~ewhat s~hematic.
For instance, in a zone spaced somewhat downstream of the ;
points of origin, the pairs of tornadoes originating in
one jet appear in the figure as being somewhat separated
from the pair of tornadoes originating in adjoining jets,
whereas, in fact, the tornadoes of adjoining jets would
be substantially contiguous.
Turning now to the illustration in Figure 8,
it is assum~d that the fiberi~ing center there shown is
the center originating at the jet orifice b of Figure 7.
The tornado 43b is also there sho~n/ as is the intervening
laminar zone 44b. The lower pair of tornadoes ori~inate
in the reg.ion within or under the deflector plate 40, Fig-
ure 8 being a sectional view showing only the lower tornado
-24-
:
. .
48b~ whi~h oriy~nates behin~ Lhe zone ~4b. The direction
of rotation o. these lower tornad~es originated as a result
of the combined action oE the jet orl the underside of the
plate 4U, together with induced air currents joining th~
jet stream, and it is here noted that the currents in the
lower pair of tornadoes are of lesser intensîty or velocity
than the currents in the upper pair. Moreover~ the direc~
tion of the currents flowing in the tornadoe5 of the upper
pair has a dominate influence upon the action of the system
when the stream of attenuable material is introduced first
into the laminar zone and then into the jet flow downstream
of the point where the tornadoes merge.
Because o the jet flow in the laminar zone and
in the pairs of tornadoes, particularly the upper pair
of each g~oup~ the introduction of the stream of attenuable
material, which is indicated in Figure 7 at S for the iber-
izing center including the jet o.ifice b, results in the
progression oE the stream into the laminar flow of the
central zone. This carries the stream into the zone ot
high velocity lying between the pairs of tornadoes and,
in consequence, the stream is attenuated as is shown in
Figure 7. It is found that this attenuation occurs sub-
stantially within a planar zone indicated in Figure 7 at
P. The action o~ the pairs of tornadoes causes a whipping
of the attenuated fiber substantially within the planar
zone P, so that this attenuation does not result in pro-
jection of the fibers being formed laterally toward the
adjoining jets.
-25-
.
- . .
Further jet flow causes the jetJ together with
the attenuating fiber carried therebyv to penetrate the
upper boundary of the blast 18, the je~ flow still retain-
ing sufficient kinetic energy t~ effect such penetration
of the blast, and thereby initiate a second phase of fi~ber-
ization which proceeds or is effected, in accordance wi~h
the principles fully explained in the prior Canadian appli-
cations referred to above. Indeed, in the region of pene-
tration oE the jets into the blast, the flow and velocity
of each jet is still sufficiently concentrated near the
c~nter of each jet so that each jet acts individually to
develop a zone of interaction in the blast. ThuS, from
Figure 7 it will be noted that in the zone of interaction~
i.e. in the toration zone, a pair of oppositely rotating
whirl5 or tornadoes indicated at TT, are generated, thereby
developin~ the curren~s which cause further attenuation
of the fiber being formed. The fiber is thereafter carried
by the combined flow of the jet and blast to a suitable
collection means, for instance a travelling perforated
conveyor such as indicated diagrammatically at 26 in Figure
1.
As will be understood, both in the laminar zone
adjacent to the edge of the deflector and also as the jet
flow progresses downstream, air is inducedJ and this in-
duction of air is clearly indicated by arrows applied tothe jet flow in Figure 7. Such induction of air currents
is also clearly indicated in Fiyure 8.
-26-
~ . - . , .
Ha~.~ing in mind the fo~egoi.ng c3escription of the .
general nature of the e~uipment and operation contemplated
according to the present invention/ a~ention is now called
to certain permissible variations and ranges of operating
conditions which may be employed.
First with regard to the relative positioning
of the jet orifices and the guiding or deflecting means,
such as the guiding plate 40, it is contemplate~ that the
arrangement of the jets and the guiding plate should pro-
vide Eor spreading oE the jets so that adjacent jets im-
pinge upon each other substantially at the edge of the
guide platesO This is the condition illustrated i~ Figure
7 and it will be noted that with this arrangement, the
- points of origin or the apices of the upper pairs o~ tor-
nadoes are at the edge 41 o~ the guide plate 40.
The jets and the guide plate may be ~rranged
so that the jets impinge upon each other at points somewhat
ups~ream or downstream of the edge of the guide plate;
but it is preferred that the impingement of adjacent jets
upon each other be maintained quite close to, but not
necessarily precisely on, the edge of the plate, because
in this condition, maximum stability of the tornadoes is
attained, with consequent maximum stability oE the inter-
vening laminar zone of the jet. In turn, the stability
of the laminar zone is important in the stabilization of
the glass feed into the system.
-27-
~ )5~1~
If the ~oint ~f impingement of adjacent jets
is spaced appreciably downstream of the edge of the g~ide
plate, the tornadoes become unstable because their apices
ori~inate in free space rather than at the edge of the
plate. When the apices of the tornadoes originate in ~ree
~pace, they are subject to fluctuations by stray ~as cur~
rents and in consequence tend to shift in position; but
if the apices originate at or substantially at the edge
of the deflector plate they are l~ss sensitive to stray
currents and, indeed appear to "attach" themselves to the
edge of the plate in a stable position~
On the other hand, if the adjacent jets impinge
upon each othe~ at a point spaced appreciably upstream
of the edge of the guide plate, the formation of the tor-
nadoes is impaired because the guide plate itself preventsproper formation of the tornadoes.
..
It is also of importance in providing for genera-
tion of the upper pair of tornadoes at the edge 41 of the
guide plate, that the edge 41 be located at or approximately
at the central axis of the jet. If the edge of the guide
plate is raised substantially, the de~lection is correspond- -
ingly diminished or even eliminated, in which event no
tornadoes will be generated~ On the other hand, if the
edge of the deflector is located excessively low, for in
stance below the lower boundary of the jet, there is a
-2~-
:~ .
~ 9it,
tendency for the tornadoes to diminish ir. th2ir or~aniza-
tion and provide only for uniform or parallel flow through-
out the entire section of the jetv rather than for the
desired higher velocity helical or vortical flow of the
tornadoes.
The generation of the tornadoes under the most
favorable conditions, i.e. under the conditions in which
the apices are "attached'l to the edge of the deflector,
produces the most stable tornadoes and thus also the most
stable operating conditions with respect to the feed of
the glass stream a~d its attenuation in the planar zone
P above described.
In connection with the advantages of the tech-
nique of the present invention, it is to be noted that
15 - the technique is capable of producing fibers of a wide
range of fiber diameter, even fipers of smaller diameter
than those produced by the toration technique ~f the Cana-
dian applications above identified. However, of special
importance and significance is the fact that the technique
of the present invention is capable of producing fibers
of a given diameter at a substantially hicJher "pull rate"
:
than is possible with the toration technique of tbe Cana-
dian application~ ~ully identified above~ The pull rate
here referred to is the rate at which the fiber may be
formed from a given orifice or supply means for the atten-
uab~e material. In accordance with the technigue of the
.~
-29-
present invention, the pull Lat~ may ~ven be as high as
150 kg/hole per 24 hours. This and other operational fac-
- ~ors will be referred to again hereinafter with particular
reference to Figures 11, lla and llb and the related tab-
ulated information given in the specification herebelow.
As above indicated, the first phase or stage
of the attenuation techni~ue of the present invention may
if desired be employed independenkly of the second or tora-
-tion stage, and this first stage, although not capable
of producing fibers as fine as those produced when both
stages are used, does produce fibers that are fine enough
for certain uses and are capable of being produced at a
relatively high pull rate~
- Turning now to Pigures 11, lla and llb and also
to the information tabulated herebelow, it is first pointed
out that the representation of the various components of
the system, particularly in Figure 11, is given in a manne~
- to facilitate ex~lanation of the ranges of dimensions and
angles, and ~oes not necessarily illustrate the preferred
values in all of the ranges.
:,
Figure 11 illustrates the three major components,
i.e. the means for developing the blast, the means for
developing the jet, and the means for introducing the atten-
uable material, each of these three means being shown in
-30-
.
.
, , . . ~,.. -,
~, . ~ . .. .
sec~ion in the same generat manner as in Figures 2 and
8, bUt in Figure 11 symbols or le~ends have been applied
- to identify certain dimensi-ons and angLes, all of which
are referred to in one or another of the tabulations here-
below. Some of these symbols or :Legends appear in Figureslla and llb.
First, with reference to the bushing 22 for the
supply of the attenuable material, see the following table:
TABLE I
tmm~
Symbol Preferred Range
Value
dT 2 1~3 5
lT 1 1~ 5
15 lR 5
R 2 1~ 5
DR 5 1--~ 10
With reference to the ~et supply and the deflec~
tor, sce the fo1lowing table:
' ''` '
-31~ ~
T~
(mm, degree)
. Symbol Preferred Range
Yalue
dJ 2 0.5~ 4
lJ 7 1 ---~
Y Close to lower about 3-~ about 4
J end of range
D 4 2 -~ 10
.1JD -. - O _O . O~
JD 45 3S ---~ 55
~CJB 10 0 ~ 45
JD 3 - 2 ~ 5
LJD 3 2 ~ 5
In connection with the values indicated for
it is pointed out that zero value represents the position
::
of the deflector in which the lowermost portion of the ~:
free ed~e of the deflector lies on the axes of the jets,
a negative value for 1~D representing a position o~ the
deflector above the jet axes~
:: ',;
In connection with the angle identified above ::
as ~ JD~ it is to be noted that downstream of the edge of
the deflector, the jet spreads or enlarges, as will be
evident from Figures.l, 2 and 8. However, the angle of
~5 this spreading is not the same as the angle represented
by the symbol ~ JD~ because the deflector causes the jet
to alter its path and also influence the extent to which
the jet spreads.
With regard to the blast, note the following
table:
TABLE I.~I
(~n)
Symbol Preferred Range
Value
B 10 5 ~ 20
In addition to the foregoing dimensions and angles
involved in the three major components of the syst~m, cer-
tain interrelationships of those components are also to ~;
be noted, being given in the table just below~
TABLE IV
(mm, degree~
Symbol Preferred Range
Value
ZJF . 8 3 S 15
: ZJB 17 6~ 30
~XBJ . _5 -12A - ' ' > +13 ~ ;
XJF 5 3 ~ 8
~, - .
~ DB 45 35 -- ~ 55
In connection with the symbol X~J~ it will be noted that
in the illustration of Figure 11, XBJ is indicated at a
negative value, i.e. with the blast nozzle in a position ; :
(in relation to the direction of ~low of the ~last) which :: -
is upstream of the position of the jet.
~,;
,;~ ,
'~:
.. . .:
"' `'I
....... , ., . .. ~ .. . ,...... . , , ,, , " " ,, ,
~05~
As in~icated hereinabove, it is contPmplated
according to the present invention that the carrier or
secondary jets be placed sufficiently closç to each other
so tbat they impinge upon each other in order to develop
the pairs of tornadoes in each carrier jet. Any convenient
number of fiberizing centers may be established/ each cen-
ter comprising a delivery device for the attenuable material
and an associated jet, and since each carrier jet must
impinye upon another jet at each side thereof, it will
be seen that the number of jets must include two more than
the total number of delivery means for the attenuable
m~terial, the two "extra" jets being positioned at the
opposite ends of the series of jets.
The number of fiberizing centers may run up to
as many as 150, but in a typical installation where glass
or some similar thermoplastic material is being fiberi~ed,
a bushing having 70 delivery devices or orifices is appro-
priate~ In such a case, there would necessarily be 72
jets. -~ ~
::
In connection with the operating conditions,
it is first pointed out that the conditions of operating
the system according to the present invention will vary
in accordance with a number of factors, for example in
accordance with the characteristics of the material being - ;~
attenuated.
-34-
~g 30~9
As above indicated, the 5yS ~eTn cf the present
invention is capable of use in the attenuation of a wide
range of attenuable materials. In the attenuation of glass
or other inorganic thermoplastic rnaterials, the temperature
of the bushing or supply means wi;Ll of course vary accord-
ing to the particular material being fiberi%ed. The tempera-
ture range for materials of this general type may fall
between about 1400 and 1800C. Wiith a typical glass com-
position the bushing temperature may approximate 1~80~C.
The pull rate may run from about 20 to 150 kg/hole
per 24 hours, typical values being from about 5Q ta about
80 kg/hole per 24 hours.
Certain values with respect to the jet and blast
are also of significance~ as indicated in tables just below
in which the following symbols are used.
T = Temperature
p = Pressure
V - Velocity
~ = Density
TABLE V -_JET SUPPLY
Symbol Preferred Range
Value
pJ (bar) 2.5 1 - -~ ~
TJ (~C) 20 ~ 1500
V~ ~m/s) 330 200---~900
~ 2) (bar) 2.] 0.8~3.5
TABI.E ~ BLAST
Symbol Preferred Range
Yalue
pB (mbar) 95 30 ~ ~25~
S TB (C) 1450 1350~ 1800
VB ~m/s) 320 200 ~ 550
~V2~ (bar) 0.2 0.06~0.5
Wi~h regard to the jet and blast, it should be
kept in mind that it is contemplated according to the
present invention that the deflected jet may be utili~ed
alone for attenuation of certain materials, without the
employment of the blast in combination with the jet. It
is also to be kept in mind that where both the jet and
blast are employed, it is contemplated that the jet shall
have a cross section smaller than that of the blast and
shall penetrate the blast.in order to develop a zone of
i~teraction in which the secondary or toration phase of ~:
the attenuation will be effected. For this purpose, the
jet must have greater kinetic energy than the blast, per
unit o~ volume of the iet and blast in the operational
area thereof. The jet may have kinetic energy of from ;~:
1.60 to 60 times that of the blast, a typical ratio being
10 to 1. Thus, in terms of the kinetic enersy values given :~
in Tables V and VI above: ~ 2~J = 10
S~ ) B . ~ ~
;';;
......
--36--
-
~;
EX~PLE
In equipment of the kind illustrated in Figures
l to 6 and having 70 fiberizing centers, a ylass of -the
following composition was attenuat:ed.
Si2 ~3.00%
Fe~03 0.30
Al23 2.95
CaO 7~35
MgO 3.lO
Na~O 14.10
K20 0.80
23 5~90
BaO 2.50
(Parts by weight)
The bushing temperature was about 1500C and
the jet and blast temperature were respectively about 20C
and 1500C. The ratio of the kinetic energy of the jet
to the ~last was about lO to 1. The pull rate was 55 kg/hole
per 24 hours.
:
The fiber diameter after both stages of atten- ;~
uation averaged about 5 microns.
" . . ..
