Note: Descriptions are shown in the official language in which they were submitted.
1~35~28
~ield o~ the Invention
q'he present invention relates to the proces~ g of ~ibres,
and more paIlticularl~ 9 to methods for productioll o~ ~ibrous
sheet matexials and apparatu~ for carxin~ out the same~
T'he present i~ve~tion can mo5t advarltageously be used in
..
pulp-a~d-paper9 textile a~d constructlon--material industries
for pxoducing various kinds o~ papar, board, non-woven fabric,
felt~ construction boardæ~
Back~rou~d of the Invention
To produce a ~ibrous sheet material it i5 esse~tial to ob
tai~ a uni~orm distribu-tio~ o~ ~ibrous material i~ a ~as
stream ~ith a predetermined dispersity value o~ the air-fibre
stream a~d to maintai~ the initial dispersit~ value of bhe
air-~ibr~ ~txeam along the e~tire path of the ~low.
q'he air-fibre stream mu~t possess a speci~ic ~luidity
e~abling t~le shape of the stream to be tra~s~ormed to a
flat one 9 as well as the i~ternal structure o~ the aix-fibre
stream to be trans~oxmed i~ order to obtain a homoge~eous
~ibre distribution throughout the stream~
The dispersity value of the air-~ibre stream is aæsumed
to be a ratio o.~ a volume of discr~te fibres or small ~ibrous
aggregabes to a volume of a~ indi~id~al fibre of mode-length9
i~eO the ~ength which predominates i~ the fibre le~gth dist-
tributio~
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~L~38531 28
The ho:~o~eneous f.ibre distributio~ i.n the ai.:~ stream
assumes the fibre concentration i~ each i.ndividua:L stream
volume to have little or no fluctuations.
The dispersity value of th~ air~fib.re stream a~d the
homo~eneous ~ibr~ dis-tribution throughout the stream decides
the degree o~ uniformity of the structuxal homoge~eity o~ the
obtained fibre sheet material, while the degree of tha ~ibre
co~ce~tratio~ in the air stream determines the amou~t o~ gas
to be remo~ed from the air-~ibre mixture to ~orm a la~er o~
fibrous material on a flat screen,
0~ one hand, the dispersity value of the air-fibre sus-
pension is reduced due to high autoadhesion of fibrcs 7 i.e.
grouping of ~eparate fibres takcs place. ~o decrease the
probability of fibre collision causing the adhesion and
grouping d~e to turbule~t forces induced in the moving air~
~ ibre stream9 the fibre concentration must be low. Generall~,
fib~e conce~tration is to be in the ra~ge ~rom 5 to 30 g/m3
depending ~po~ the properties of the material to be produced
and upo~ the kind o~ ~ib.re.
Moreover, a high fibre conce~tration of the air-fibre
stream decreases fluidity of bhe stream9 said ~luidit~ being
an obligatoxy prexequisite ~or trans~orming the outer shape
of the air-fibre stream~ e.g. a cylindrical shape into a flat
one 7 as well as for changi:~g the internal structure of the
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air-fibre stream to attain a uniform distribution o~ the ve-
locity field in the stream cros~~s~ction, this being nec~ssary
for forming a u~i~orm layex of f1brous ma~erial on a flat
screen.
'Thus 9 ~ low ~ibre concentration of the gas fibre stream
is a ~ecessa~y prerequisite for ~orming a fib~ous sheet
material~ Therefor0~ if a layer o~ fibrous material is being
formed with a high velocity, e~g. on the ~lat screen txave~
ling at a velocity ra~ging ~rom 180 -to 900 m/min9 a conside~
rable amount of gas is to be removad from the gas~ibre
mixtuxe.
The flat screen with fibres settled thereon to ~orm a
layer o~ fibrous material has a high xesistance coe~icien~
valued fxom 20 to 500, depending on the kind of fibr0 and on
the fibro~ layer thic~ness. ~herefore, the removal o~ great
amount of gas per unit of time, required in a high-speed
ma~u~acturing o~ the ~iborus layer 9 leads to an increasad
electric power cons~nptio~0
The power expended in defeating the resistance can be redu-
ced with adequate increase in an acti~e a~ea o~ the flat scree~.
~his leads, however, to objectio~able irlcIe~se in the size of
the equipme~t and9 as a result, to a~ increased metal input.
0~ the other hand, the power consumped in defeating th~
resistance developed o~ the screen duri~g a layer ~o~ming
process when gas is being removed through the screen and
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fibrous layer precipitated the~eon~ ca~ be reduced by increasin~
the co~ce~tration of fibres i.rl the gas-~i.bre stream. In this
case the gas-~ibre stream must be ex~a~ded before it is
supplied onto the scree~ in ordex to achieve a u~iform dis-
tribution of the velocity ~ield, a homogeneous distributio~
o~ fibres over a~ e~tire ~tream volume, and an increase i~
dispersity value of the gas~fibre stream, all this making
it.possible to obtai~ a layer of fibrous material of homoge-
neous structure, iOe. the material u~iform by it~ mechanical
-ancl physical charact~risticsO
Known in the art is a method ~or productio~ of ~ibrous
sheet material (cf. US Patent ~o 2~689.985). ~ccordi~g to
this method th~ fibrous material is fi~aly divided and is
delivered into the expanding ~as ~tream to be transformed
therein by mechanical intermixi~g, whereby the uni~orm distri- :
bution o~ the velocity ~ield i~ achieved and a æeparation
of large aggregates i~o small fibLous ~olids takes place.
~he~ the gas-fibre mixture is precipitated on the screen to
form a fibrous layer thereon.
A device for carrying out this method ~or productio~ of
fibrous sheet material comprises a disc mill to i~dividuali~
æe the fibres, said mill being co~nected through a dischar-
gillg pipe to a di~f~ser having divergirlg side and fror~tal
walls, a;~d a ro~ati~g roller axra;nged thereirl, the latter
comprising teeth0 '~he gas-fibre stream is trans~ormed ~vith
.
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mecha~ical agitation cau~ed by the rotatin~ roller9 thus
resulting in homogeneous fibre distribution throughout ~ho
entixe volume o~ the gas-fibra stream~ 'rhe gas-fibre stream
is supplied from the diffusex o~to a ~lat screen.
PDou~ted ~der the screen i5 a suction box for removing
gas from the gas-~ibre stream supplied onto the scree~ during
the layer ~orming process,
The disadvantage o~ the abovementioned method and appa-
ratus ~or carryi~g out the same consists in that~ because
of local fibre ~locculation caused by mechanical agitatiQn~
it enables the gas-~ibre stream having fibxe conce~tra~ion
as low as 5-10 g/m3 to be trans~ormad~ When a gas-fibre stream
o~ higher concentration is used9 homogeneous distribution
o~ fibres throughout the entire volume of the stream is
disturbed.
Furthermore, the gas-fibre stream supplied onto the ~lat
scxeen has a low ~ibre concentration. This leads to an inc-
reased electric po~er consumption e~pended i~ defeati g the
resistance developed on the flat screen during ~he fibrous
layer ~orming process when a great amount of gas is being
removed through the screen and fibxous layer settled thexeo~.
A gas-fibre stream o~ higher fibre concentratio~ ca~ be
supplied onto the screen i~ the tra~sforma-tio~ of the stream
befo~e it is supplied o~to the flat scree~, is attained with
mu~tiple dispersion o~ fibres in the gas streamO
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K~o~vn in t~e art i5 a method for producbion of fibrous
sheet ma~erial~ In thls l)rocess the fibrous material is grou~d
and is fed into the e~pallding gas stream. rThe obt~ined ~as-
-fibxe stream is subjected to multiple dispersio~ and the~
is supplied o~to the fla-t screexl to form a ~ibrous layer
thereon,
An apparatus ~or carrying out this proce~s comprises a
diffuser havi~g diverging side wallsS with iks inlet ope~i~g
communicati~g with a ~as-~ibre stream su~plyi~g pipe li~e,
while its outlet ope~ing is co~ected with a rectarlgular
upright chamber~ Several faixed airfoil-fo~m bodies are arra~-
~ed in the chamber with their pla~es parallel to the chamber
side walls, the upper portion of each body disposed inside
the di~user9
When the gas-fibre stream is impacted agaiLsk the ~aired- :
-~o~m bodi.ss~ a multiple dispersio~ effect occurs due to the
resilie~t repelling of the~ibres agai~ the co~vex surfaces
of the faired-form bodies, ulhereby the gas-fibre stream is
distributed u~iîo~m~;y edgewise over the recta~;ular chamber,
a~d the u~iIor~ distributiorl of the velociliy field is a-ktai:lledO
q'he abovementioned method for production o~ ;~ibrous
sheet material and the apparatus fox car~ying out the same,
however~ ~ail to transform a gas ~ibre stream having fibre - :
conce~trat;ion higher tha:~ 5 to 15 g/m~ the gas-Iibre
stream o~ highex fibre conce~ration is îe~l to îaired-:from
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35~2~3
bodies, the power o~ th~ ditstribution fields is .i~su~ficie~t
for transfo.rmin~ the gas-~ibre stream, i.e. forc~s developed
in the proces~ axe insufficie~t for inte]r,mixing the ~a~-
-fibre stream containing a great ~uantity of ~ibxes per
unit o~ its volum~. ~s a xesult, a unifo~ ~elocity ~isld
distribu~io~ is not achieved i~ the tra~f`ormed gas ~ibre
stream.
Moreover, the ~ibre co~c0ntratio~ of the stream supplied
onto the ~lat scxeen conti~ue to be lowg this leadi~g to an
increased exp~nditure of curre~t, consumed in de~eating the
resi~tance deve~oped on the f'lat screen duri~g the ~ibrous
layer forming process, since a gxeat amou~t o~ gas is to be
removed through the screen and f'ibrous layer precipitat~d
thereon.
q'he gas fibre stream can be transform0d, simultaneously
using ~he mulGiple fibre dispersio~ effect and transYersal
pulsations induced in the gas-fibre stream.
Kno~n in the art is a method for production o~ fi~rous
~heet material. I~ this process fibres are dispersed i~ a gas
stream to obtai~ a gas-fibre stream~ the gas-fibre stream
being then distributed i~ a ~latte~ ~orm. ~he obtained ~lat-
ten ou~ gas-Pibre stream is txansformed b~ supplying it to a
cylind~x elem~nt~
The intera~tio~ of the flatten-~orm ga~-fibre stream
with the cyli~der causes multiple ~ibre dispersio~ e~ect
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resul-ti~ from the resilie~t repelli~g o~ ~ibrous solids
a~ai~lst the cylinder sur~aceO Thu~ ~ibre sol.id sh~edding, i.e.
increasing o~ the dispersion value, take~ place.
~ 'he cylinder~ scheduled in th~ appa~atu~, prov~de~ f'or
tra~sversal pulsations in the ~as-fibxe stream flowing over
the cyli~der, thus resulting in the uniform distributio~ of
the stream velocity field~ The traIIsformed gas-~ibre stream
is the~ supplied onto the flat screen to form a ~ibrous layer
thereonO l`he fibrous layer is subjected to a subsequent
; treatment to obtai~ fi~ished sheet materialO ~:
A device ~or car~ing out the abo~emen-tioned process for
productio~ of ~ibrous sheet material co~prises a~ elongated
slot nozzle having mutually perpendicular diverging side walls
and convergi~g ~rontal walls~ the inlet opening o~ said nozzle
being i~ co~nunicatio~ wi-th a means ~or dispersing ~ibres in
a gas stxeam to obtai~ a gas ~ibre mi~ture, while its ou~let
opening is con~cted witk a chamberP ;~
Arxanged underneath the elo~gated nozzle7 along its enti~ -
rQ length, is a cylinder ~ixed with its ends to the side
walls o~ ~he chamber~ A special lattice f'or eli~inati~g stream
turbulence is placed downstream ~rom the cylinder a~d spa~s
the chamber cross-sectio~.
The layer ~ormi~g process takes place on a ~lat scree~
with the help o~ a suctio~ bo~ disposed u~der the chamber~
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~ hs disadva~tages of the described method for production
o~ fibrous sheet mat~rial and o~ the apparatus for carl~ing
out said method co~sist in9 that this apparatus pe~mit~ to
txansform ~hc gas-~ib.re stream having fibxe concentrutiorl onl~
of 10 to 30 g/m3. When the gas~f`ibre s~ream is delivered.
onto the cylinder, the transversal pulsations in the gas
fibre stream ~lowing past the c~ dex, are generated, power
of said pulsatio~s gradually decreasing as the stream mo~e~
away ~rom the cylinder. There~ore, in case the gas-~ibre
stream of higher fibre concentration is ~ed to the cylinder,
the power of distribution fields and that o~ transve.rsal
pulsations are i~su~icient for trans~orming the stream and
for obtaining the sheet ~aterial homogeneous in structure,
No one o~ the stream transformi~g apparatus can pro~icle
~or the desired degree o~ transforming o~ the stream having
high ~ibre concentratio~.
: Consequently, only a gas fibre stream having low ~ibre
concent~atio~ can be supplied on the flat scxeen i~ order
to pxoduce sheet material homoge~eous in structure. ~his re-
: sults in an increa~ed power cor~sumption9 since a great amoun~
o~ gas is to be removed per unit of time during the layer
~orming process O
Summar~ of the Inventio~
It is an object of the pxesent inventio~ to provide a me- ~ :
thod fo~ p~oduc~io~ o~ fibrous sheet material a~d a~ appara
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tus fo.r car~ying out the same, such as to trans~orm a gas-
~ibre stream in order to obtain o~ a ~lat screen a ~iblous
layer homogeneous .i~ stllucture, the gas-fibre s-tream bein~
of high fibre co~centrationO
Another object of the present invention is to provide a
process for production o~ f`ibrous sheet materlal homogeneous
i~ structure~ which process is characterized by an increased
production output,
Still another object of the present inve~tio~ is to redu~
ce ~xpe~diture of current by virtue o~ reductio~ o~ amou~t of
~as to be removed per u~it of time durin~ the fibrous layer
forming processO
Yet another object of the present invention is to
decrease size~ and metal consumption needed ~or the appara-
GUS made therefrom.
With these a~d other objects in view there is provided
a method for production o~ ~ibrous sheet material~ comprising
dispersing of fibres i~ a gas stream ~o obbain a gas-fibre
s~ream9 supplyi~g the gas-fib~e stream onto a ~lat scree~,
removing gas from the gas-fibre stream thIough said screen ~:
to form a ~ibrous layer thereon9 a~d its subseque~t treati~g : .
to obtain a ~ibrous sheet material~ wherei~9 accordi~g to ~ .
the i~ventio~, a part of gas is removed ~rom the gas-~ibre
s~xeam p~ior to 5uppl~i~g it onto the ~lat screen so as to
bri~g ~ibre co~ce~tratio~ in the gae-fibre stream up to
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20 to 500 g/m3 t said concentration bei~g chosen il~. accordance
with the kind a~d proper~ies of fibres9 a~d trans~ersal pul-
sation~ induced in the gas-fibre stream in -ths course of
moving, are dampedO
l`he gas-fibre stream i~ trans~ormed ~lccording to the pro-
posed methocl so that its ~ibre co~centrat:Lon increa~es ~rorn
5,o-50 g/m3 to 20-500 g~m3. ~`his occur~ due -to the existence
o~ motion of fibres with respect to gas, whereby the fibres
approach each othex in a regular manner9 this resulting in
increase in local fibre concentrationO Owin~ to that 9 a part
of gas which is purged of fibres ma~ be removed independently
of the part o~ gas saturated wi.th fibresO
Vu~ to the provision o~ dampi~g of transver~al pulsa-
tions induced in the gas-fibre stream in the course o~ moving~
sheet material of homogeneous structure is obt~ined, this
bei~g a~ieved by elimi~ation of local flocculation taki~g
place in the gas-~ibre stream as its fibre concentration
increases O
It is advisable to ~eep the amount o~ gas being removed
f'rom the gas-fibre stream prior to supply it onto the flat
screen wi.thin the limits ra~gri~g from 20 to 90 percentO
It is also desirable to damp the transversal pulsatio~s
by contracti~g the gas-fibre stream i~ the direction normal
to the path of the stream movement~
The contracting of the gas ~ibre ~tream in the directio~
~ormal to ths path of the stream provides ~or con~used ~low
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o~ the streai~ with uniform distribution o~ the velocity Pield
profile. ~his co~tributes to u~iform re~ular fibre thicke~ing
and to reductio~ o~ the cross-stream cornpone~t ol~ th~ stream
turbul~rlce .
With these a~d other obaects in view~ there is also
provided a~ apparatus for carryi~g out the method for produc-
tion of ~ibrous sheet material9 comprising a slot ~oæzle
having ~ide walls ~ormal to converging ~rontal walls, an inlet
ope~ing o~ said ~o~le bein~ con~ected with a means for dis- :
per~i~g o~ fibres in a gas stream~ while its outlet opening
is communicated with a chamber, a flat screen adapted to
foxm a ~ibrous layer thereo~S mou~ted under said chamber, a~d
a suction box arranged under the ~lat scree~, wherei~9 accox-
di~g to the invention, the side walls of the slot nozzle are
i~ parallel relationship wiGh respect to each other, a means
for removing a part of gas from the gas-fibxe stream is
arranged within the chamber under the outlet opening o~ :
the slot ~ozzle, and the chamber is provided with bra~ch
pipes for gas exhau~t, mou~ted substantiall~ in the upper
portio~ of the chamber. ~ .
The parallel arrangement o~ the side wall~ of ~he slot
~ozzle eliminate~ a~y considerable elongation o~ the velocity
~ield pro~ile, i.e. provides ~or uni~orm di~tributio~ o~ the
~eloci~y field pro~ileO
Owing to the provision o~ the means ~or removing a par~
of ga~ from the gas-~ibre streamJ disposed u~der the outlet
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ope~i~g of the slot nozzle 9 gas xemoving through the bra~ch
pipes arranged iIl the upper portion o~ the chambe:r is achie-
ved~ whereby fibre concentratio~ of th~ stream increases,
~vhile expe~diture o~ current consul~ed in dividing the media
during the ~ibxous layer fol~ing process i~ reduc~d~
~ According to one embodiment o:E the i~ntion~ the mea~
for xemoving a part o~ gas from the gas-~ibre ~tr~am i~ em-
bodied as a plurality o~ guidi~g bodies arxar~ed in parallel
one u~der the other and spaced 3 to 20 mm apart, so as to
form a vextical row disposed u~der one of the fxontal walls
of the siot nozæle a~d inclined at 3,5 to 11 rela-tive to
the axis o~ the slot nozzle, each of the guidi~g bodies being
inclined ~ith respect to the a~is o~ the slok ~ozz:Le at a.n
angle ranging between 10 and 35 ln the directio~ of gas
fibre stream movemerltO
l'he mea~s ~or removi~g a part of gas from the gas fibre
stream made as a plurality of guidi~g bodies arra~ged in
parallel o~e under the other to ~orm a vertical ro~ disposed
unde~ one of the fro~-tal walls of the slot nozzle, i~clined
at a particular arlgle with the respect to the axis of the slot
~ozzle~ developes resistar~ce to the gas-~ibre stream lea~ing
the outlet opening of the slot nozzle~ whereby a part o~ gas
charlges its initial direction arld is gradually removed whe~
passing through gaps between the guidi~g bodies as the gas-~i
bre stream îlows along the row o~ guidirlg bodi es .
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~ u~ to the provision of gradual removal of gas tbu~ough
the gaps between the gu:iding bodies, ~ibre conce~txation of
the strec~m increases, this contributi~g to u~iform di~tribu-
tion o~ the velocity field pro~ile of the gas-fibre streamO
O~ving to thc inclination o~ the row of the guidinO bo-
dies with respect to the axis o~ the slot ~o~le, the ga~-
-fibre stream is co~tracted as it flows along the guidi~g
bodies~ thus i~creasing homoge~eity of the gas-fibre stream6
According to another embodiment of the invention~ the
means for remo~ing a part of gas from the gas-fibre ~tream : :
is made as a plurality o~ guiding bodies arra~ged in para-
llel o~e under the other and spaced 3 to 20 mm apart so as
to form two vertical rows~ each disposed under o~e frontal
wall of the slot nozzle a~d incli~ed at ~,5 to 11 with
xespect to the a~is of the slot no~zle 9 each of said guiding
bodies bei~O inclined relative to the axis of the slot
~ozæle at an angle xangi~g between 10 and 35 in the di~
rection of the gas-fibre stream movement? while the guidi~g
bodies of one row are in a mirrorimage position with respect ~ :
to the guidi~g bodies o~ the other rOW4
Such a design of the means îor removing a part of gas
from the gas~f`ibr~ stream, incorporatiIlg guiding bodie~;
arra~ged i~ parallel o~e u~der the other so as to ~orm two
vertical rows 9 each o~ the rows being disposed u~der one
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frontal wall of the slot noz~l~, enables the len~;th o~ an
active zone throu~h which gas is removedp to be doubled, thus
pe~littillg to reduce sizes of the u~it, while maintai~i~g
the pxoduction outpu-t at the same level.
Due to the converged position of the guiding bodles~
contl;acting of the gas-fibre stream is effected in the direc
tio~ ~ormal to the direction of its movement~ whereby tra~s-
versal pulsations are partially damped.
It is advisable to make the guiding bodies in the form
of blades~
Owi~g to the blade form o~ the guidin6 bodies, the gas~
-~ibre stream is ~revented from ~ibre loss when a part of gas
is being removed.
It is advisable to arra~ge the guiding bodies o~ each
row ~o as to ~o~m at least two groupes of blades and -to
provide e~ual gaps between the guidi~g bodies in each group,
the gaps between the guiding bodie~ of the upstream group
being gxeatex tha~ the gaps betwee~ the guiding bodies o~
the doY~nstream group.
Due to the provision of ~wo groups of guiding bodies in
each row~ said guiding bodies in each group being equally -~
spaced to each other a~d -the gaps betwee~ the guidixlg bodies
of tho upstream group being greater than the gaps betwee~ ~,
the guiding bodies o~ the downstream group~ removal of a
par~ o~ gas without ~ibre loss i~ ensured as the g~s-~ibre
stream flo~s alo~g the row of guiding bodie~ ,
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'l'he gap between the guiding bodies of the upstrea~ ~rou~
should not exceed 20 mlrlp ~hile the ~;ap between the guiding
bodies o~ the downstream group should not be und~r 3 mm.
Other objects, advantages and fea~ures of the inve~tlon
will become appare~t ~rom the ~ollowi~g detailed description
of the inve~tion and the accompanying drawi~gs, i~ which:
~ IG. 1 is a flow dia~ram illustrati~g a method f3r
productio~ of ~ibrous sheet material, according to the prese~t
i~ve~tion;
FIG. 2 is a diagrammatic vie~ of an apparatus ~vhi.ch
u-tilizes the m~thod ~or production of fibrous sheet material;
accordi~g to the i~vention, general view;
~IG. ~ is the same as shown in ~IG.~, longitudi~al ~:
sectio~; .
FIG. L~ iS an enlaxged vi.ew of the assembly A sho~ in
FIG 9 2;
~ IG. 5 is an enlarged view of the assembly B shown
i~ FIG. 2;
FIG. ~ is a view of an alternative fo~m o~ an appaxatus
for carrying out the method for production of ~ibrous sheet :
material t according to the inventio~;
~ IG, 7 is the same as show~ in ~IG. 6, perspective ~iew;
FIG. 8 shows a~other embodiment of an apparatus for car-
x~ing out the method of the present inventio~ ~or pro~uction
o~ fibrous shee-t material;
_ ~8 - ;
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FIGo 9 i~ the same as shown in ~IG. 8 9 lo~gi.tudi~al
section;
FIG, 10 shorls still another embodime~t of arl apparatus
for carryi.ng out the method o~ the prese:nt inven~ion ~or
pr-oduction of fibrous sheet material~
A method ~or production of ~ibrous sheet material is
illustrated b~ a flo~v diagram show~ i~ F:LG. 10
~ ibrous material a~d gas are ~upplied to a mea~s 1 ~or
dispersi~g fibres i~ a gas stream~ whereby a gas-fibre stream
2 is obtai~edO The obtai~ed gas-fibre stream 2 is delivered
thr~ugh a slot ~ozzle 3 i~to a chamber 4. Within the
chamber 4 the ~as-fibre stream 2 is co~tracted9 and due to
inertia ~orces, relative motion of gas a~d fibres is deve-
loped. When the gas-fibre stream is contracted, the gas and
fibres move in different directions due to the ~act that
the density of fibrou~ material is 800 times more than that
o~ gas. ~he Xibres travel alo~g the path coincidi~g with the
initial path of the gas-~lbxe stream 2, while a par~ of gas,
free of fibres, start~ to move i~ a direction opposite to
the i~itial direc-tion of the gas-fibre stream 2. A part of
gas removed, fibre concentratio~ of the stream i~creases~
Flow path of that part of gas, which has changed its
directio~ of movement is show~ by the arrows "a".
~ he gas~fibre stream 2 is contracted i~ the direc~ion
normal to the direction of its mo~ement, whereby the trans~
- 19 -
.
.,,.. , ~ ~ ~
versal pulsations i~lduced i~ the gas-fibre stream are gradual-
ly damped. ~'hus a u~iformity of a velocit~ field profile of
fibrou.~ material in the g~s-ibre strea~, as well as a
small-scale tu~bulent structure~ are achi.eved. 'l'his, in turn~
ensure~ high ~ib.re co~ce~txatio~ and, at the same time,
homo~eneous structure of the gas~fibre ~tream having passed
through the chamber 4D
~ he gas-fibre stream 2 is ~urther d~livered from the
chamber 4 onto a ~lat screen 5, the remaini~g paxt of gas
being removed therefrom by a suctio~ box 6 mounted u~der the ~ ;
flat scr~h 5.
~ he direction of the paxt of ga~ removed from the gas-fi-
bre stream 2 when it is bei~ laid on the flat screen 5 is
indicated by the arrows "c". A flbrous layer ~ettled on the
flat screen 5 is then subiected to a special treatme~t to
obtain a ~inished fibrous sheet matexial~
The part of gas removed from the gas-~ibre stream 2 i~ -
the chamber 4, and that removed from the fl~t screen 5
may be reused by supplying them i~to the means 1 for dis-
persi~g fibres without any additional cleaning of fibres from
gas, ~ince the fibr~ co~te~t in gas is o~ 0.02 to 0~5 g/m3.
X'hese ~ibxes may be reused a~ well.
q'hus the problem of the environ~~ment protection is
ef~icie~tly solved~
~'~
- 20 -
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, .
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,,
.
~ s~
A part of gas being removed ~rom the gas-fibre stream 2
i~ the chamber 4 is valued ~ 20 to 90 percent.
~ 'he amount o~ gas to be removed from the gas~fibre strcam
2 is chosen in ac~orda~ce with a desired mass o~ 1 s~uare
meter of the finished material arld with the length o~ ~ibre~
fcd into the dispersi~g means ~.
The amount of gas valued as 20 to 40 perce~t i~ to be
removed in order to provide for mobility o~ ~ibres having
len~th from 0~5 to 38 mm when fibrous sheet material with
high degree of structural homoge~eity, having mass o~ 12
to 40 g/m , is to be obtai~ed~
~ rom 40 to 60 percent o~ gas is to be removed ~rom the
gas~fibre stream ~ i~ case a lower mobility of fibres having
length from 0.5 to 38 mm is allowable when homoge~eous fi-
brous sheet material havi~g mass of 40 to 100 g/m2 is to be
formed,
~ rom 60 to 90 percent oP ga~ is to be removed ~rom the
gas-fibre stream 2 is case of still lower mobility of ~ibres
in the gas-fibre stream 27 ~his being permissible i~ produci~g
homogeneous ~ibrous ~heet mate~ial whose mass per square~me-
ter is more tha~ 100 g.
I~ the amoun-t of gas being removed is u~der 20 percent~
the proces~ doe~ not ju~tify the e~pe~diture o~ cu~rent9
the latter dr~tically increa~i~g because of co~siderable vo~
ll~e o~ gas to be removed per unit of` timeO
',~
- 21
Z~
It is next to impossible to remove mor~ tha~ 90 percent
of gas ~rom the gas-fibre stream 2.
An apparatus for carrying out the method for production ~ ~
of flbrous sheet material comprises a pi,pe 8 (FIG. 2) inter- ,;
connectillg the mealls 1 for dispersing fi'bres in a gas stream
and an inlet openin~ o~ the slot noz~le 30 q'he ~lot ~ozæle 3
has parallel side walls 9, 10 (FIG. 3) w:hich are normal to
converging frontal walls 11, 12. An outlet opening of the
slot nozzle 3 co~municates with the chamber 4.
I~stalled within the chamber 4 under the fro~tal wall 11
of the slot nozzle 3 are guiding boides rspresen~ing 'blades 13 ;~
(~IG. '1). ~he blades are disposed in a ~paced parallel rela-
tio~ship o~e under the other, a gap 14 therebetween ,ranging
from 20 to 3 mm~
he gap 1~ between the blades 13 is chosen in acco~dance
wlth the length of fibres used in a layer forming process. I~
the ~ibre length is ~ mm a~d under, the gap 14 is chosen from
10 to 3 mm, ~or the ~ibre le~gth equal to 20~35 mm the gap
14 is i~ the range between 10 and 20 mmO ~he blades 13 are
i~clined at an acute angle c~ with respect to the axis of the
slot noz~le 3 in the directio~ of the stream movementO
qlhe a~gle CX~ is chose~ in accordance with the masæ of
fibrous material and with the elasticity o~ fibres~ In case
the fibres posses adequate elasticity a~d the ~ibrous material
mass is suf~icient, considerable inertia forces are generated ~'
in the gas fibre ætream 2 as it mo~es alo~g the blades 13~ ~
- 22 - ..
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., ~ . .
~ 5~2 ~
To prev~t the gas-~ibre stream 2 from ~ibre 108s occurri~g
thxough the gaps 14 between the blasde~ 13, the ar~gle ~ is
set close to 35 0 Owing to this~ the fibres are repelled
against the blade surfaces toward the axis of the chamber 4 J
Moreover, such an angle pro~ides a~ additio~al resistance
of~ered by the blades 13 to the gas~ibre strea~ ~9 this
r~sulti~g in i~te~if~i~g the process o~ removing a part of
gas from the gas-~ibre stream 2.
I~ case the fibres possess low elasticity and their
mass is small~ whereby reduced inertia ~orces are developed
in the gas-fibre stream 2 as it moves along the blades 1~,
the angle ~ is set close to 10 in order to provide a
smooth movement o~ fibres not possessing an adequate elastici~
t~ to be repelled ~rom the blade surfaces, along the blades
13, Moreover, such an a~gle ~ offers a negligible ad~itional
resistance of the blades to the gas-~ibre stream 2~ this
eliminati~ fibre loss whe~ the gas i~ being removedO
~ he blades 13 are fixed with their e~d faces to the side
wall~ 9, 10 (~IG. ~) o~ the chamber 4, the length o~ each
blade being equal to the distance between the side walls 9,
10 o~ -the chamber 49
~ he blades 13 form a vertical roYv inclined with respect
to the axis of the slot nozzle 3 at an angle ~ G~ 5)
chose~l within the limits ra~ging from 3.5 to 114
~ he most angle ~ is set i~ a steep build-up of blade
resisJGance to the gas-~ibre stream 2 is to be cxeate~ i~ order ~;
~ .
`, - 23 _
.
5~8
to intensi~y the removal of ~as. I~igh inkensit~ ~sas removal
from the gas~ribra stream 2 may be effected o~ly in case th~
mass o~ every elementa~ fibre is significa~tg e,g. when
fibres having co~siderable length ox density (as~es-tos
~ibres) are used. In this case inertia forces acti~g upon
the fibres in the gas-~ibre stream 2 are great, whereby the
fibre loss with the gas being removed is ne~ligible,
Setting the row o~ blades at an angle ~ greater than
11 con-tributes to an u~duly intensive removal of gas resulting
i~ appreciable fibre loss accompanying removal o~ gas,
I~ the ~lbres are shor~ or possess low density, e~g~ hol-
low fibres, inertia forces acti~g ~hereo~9 ~re insignificant.
In this case an intensive gas removal is impermissible, sin
ce a great amount of fibrous material will be lost~ ~here-
foxe, gas xemoving p~ocess is to be per~ormed with a lower
i~tensity9 i.e. a low resistal~ce to the gas-fibre strea~ 2
is to be ~chieved. The need for satisfying these reguirements
dictates the a~gle ~ be close to 3~5.
Con~ected to the upper portiou o~ tha chamber ~ (FIG. 2)
is a bra~ch pipe 15~ ~'he flat screen 5 is found under the
chamber 4. ~he suct*on box 6 is dispo~ed under~eath the ~lat
scree~ 5. A ~ibrous layer ~ormed on the ~lat ~creen 5 is
the~ .~ed to a mea~s 7 where it is subjected to a~ter treat-
ment to obtain a fi~ished sheet materialO
= ~IGS 69 7 sho~ ahother embodiment of a~ apparatus ~or
productio~ o~ ~ib~ous sheet material~ wherei~ a means ~or
'~
,
, .
... . ~
~ 2~ -
removin~ a part of gas from the ga~-fibre str~am 2 i~ made
as a plulalit~ of blad.es 13 disposed so as to fo:r~ two ver-
tical rows~ each row being located undex o~e of the fro~tal
walls 11, 12 o~ the slot nozzle 3 a~d inclined xelative to
the axis o~ the slot nozzle 3 at an a~gle xa~giLg from 3.5
to 11.
The blades 1~ ~orming a row disposed under the ~rontal
wall 11 are positioned in a mirror-image wc~y with respect
to the blades 13 ~orming a row disposed under the fxontal
wall 12 of the slot nozzle 3 . ~he blades 13 in each row are
mounted in parallel o~e under the other and are spaced 3 to
20 mm apart9 each blade 1~ being inclined relative to the
axis o~ the slot noz~le 3 at an angle 10-35 in the clirec-
tion of the stream movement.
~ IGS 8, 9 show still another embodiment of an apparatus
for production o~ fibrous sheet material, wherei~ each ro~
. o~ the blades 13 is divided into two sections I a~d II. ~he
section I is po~itioned above the section II. ~he gap 1~
between the blades 13 of the section I is set from 20 to 10 mm9
while the gap 14 betwee~ the blades 13 of the section II is
set ~rom 10 to 3 mm.
FIGo 10 illustrates a still further embodime~t o~ a~
apparatus ~or production o~ ~ibrous sheet material, wherein .
each row o~ the blades 13 is divided into ~our sections III, ~:~
IV9 V, Vl~ ~he gap 14 between th~ blades 13 over ~he sectio~
,:; ~ . ' , , `, :; : ' '
:`, ' " " ~ . " ' ~ ~ . , '. ' . ' ' . .
~ " " ' ' ' '' '" " ' .
'
~ ~ 5~ Z ~
III i~ set withi~ 20 to 17 mm, the ~ap 14 ~e-tweel~ the blades
13 over the section IV i~ set ~rom 16 to 12 mrn, the gap 1
betiweon ~he blados ~3 ovex the section V is set ~rom 11 to
6 mm~ and ti}le same gap over the sectio~ VI is set from
6 to 3 mmO
'l~he followiIlg considerations where taken i~to account
when settin~ the ~ap distance betwee~ the blad~s in each
section~ When the ~as~ibre stream 2 ent~rs the zo~e of sec
tion I (FIG. 3), fibre concentra-tiion in the gas-~ibre stream
is lo~ and the resistance e~erted ~y fibrous material o~to
the transverqal ~low of gas during its removal is also low~ ~ -
Moreover9 due to high mobility o~ fibrcs re~ulting ~rom low
fibra conce~tration over the section I, the inertia of each
fibre particle shows itsel~ up more clearly than over the
subse~uent secbions~ Owing to that, more intensive remo~al of
gas is ~sured in the zone o~ section I, a~d a large gap
dista~ce between the blades 13 may be provided practically
without any ~ibre loss. ~he fibre concentrati.on of the ~as-
-fibre stream 2 increases as it p~sses through the zone o~
the section I and enters tho zone o~ the section IIo .-
The resistance to the tra~sversal gas ~low raises over
the sec~ion II because o~ an increased ~ibre concentrationO
The same is responsible for the low mobility o~ fibres,
æaid mobility occurring under the action o~ inertia forces.
Thus, the probab.ilit;y oY .eibre loss ~sith ga~ being removed~
incxeases .,
- 26 -
~ ~ 5~ Z~
The gap distance be-twee~ the blades 13 over the secblon
II, however, i ~ ,small, whereby the 6as removal ~Hlocity
~ becomes lower and the fibre loss is reduced~
- Thus; varyin~ the gap c~ista~ce between the blade~ 13
over each ~ectio~, gas bleeding is controlled over the entire
leng~h of the row o~ blades 13~
The proposed apparatus for pxoduction o~ ~ibrous sheet
material operates a~ followsO The ~ibres are supplied to the
means 1 (FIGo 6) ~or dispersi~g fibres in a gas stream. f~he
obtained gas-fibre stream 2 is fed thxough the pipe 8 to the
inlet opening of the slot nozzle ~. Due to the provision o~
converging ~ro~tal walls 119 12 and parallel side walls 9~
10 (FIG. 7), the cros,s sectional area of the slot nozzle 3
i6 reduced9 whereby the velocity of the gas~fibre stream 2
increases as it leaves the slot ~ozzle 3. At the same time
the gas-~ibre stream 2 is contracted, this resulti~ in
u~i~'o~ distributio~ of its velocity field. ~ `-
Upon ~eavin~ the slot nozzle 3 (FIG. 6) the gas-~ibre
stream 2 e~counters the resistance exhibited by convergi~g
rows o~ blades 13. As a result, a considerable part of gas
changes the direction o~ its moveme~t a~d, being directed
into the gaps 14 betwee~ the blades ~3, enters the chamber 4
a~d then is removed ~rom the apparatus through the pipe
branches 150
The de~sity of ~ibres being much greater tha~ that o~
the air~ the ~ibres under the action o~ inertia ~orces con
~ 27 ~
: : . . . : . . . . ,:. . . .
~ . .. -
.. .. . .
. . . - . ~ , :
. , , ~ .
. .
~ 2~
tinue their rectilinear move~lent between the conv~rging rows
of the blades 13. Q pal~t of ~ibres which make~ co~tact with
the blade surfaces impacts against these surfaces and, bei~g
repelled theref'rom due to blade orientation at a curtain
angle xela~ive to the axis o~ the slot nozzle 3~ move~
towaxds the central part of th~ cavity ~ormed by t~Jo co~-
verging rows o~ the blades 13~
As the gas is bei~g gradually removed through the gaps ~4
betwee~ the blades 13, the ~ibre conce~tration o~ the gas~ibre
stxeam ~ increases.
~ he converged position of the rows o~ the blades 13,
providing for contracting the gas~Pibre stream 2, contribu-
tes to increase i~ degree o~ homoge~eity oX the stream.
A high ~ibre conce~tration of the gas fibxe stream
causes decrease in fibre mobilityD
Upo~ passing betwee~ the rows of the blades 137 the
gas-fibxe stxeam 2 is transformed to meet the requirements
imposed there upon to ob-tain fibrous sheet material of homo-
ge~eous structule, a~d is supplied onto the movi~g screen 50
As the gas-fibre stream 2 comes into co~tact with the
flat screen 5, -the remaining part of gas is removed by means
oX the suction box 6, whereby the ~i.bres are precipitated
on ~he flat screen 5 to ~orm a ~ibrous layer homoge~eous i~
struc~ure. '~he obtained layer is then ~ed to the mean~ 7
where it is subjected to a t~eatme~t to produce ~ ho~oge~eous
~ibrous sheet material~
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l~B5il28
Example 1
Sb.eet ma-terial having a mass of 1~5 g/m2 is to be produced
from ~sbestos fibres of 2.5 mm mode-lengt;h.
a) fib.re conce~tration in the gas~fi.bre
stream 0O.. ~,.. ~.... ~..... ,.... ~.. ~........................................ ..50 g/m3
b) Yelocity of the gas fibre stre~m ..... 0 10 m/s
c) cross-stream compo~ent of gas-~ibre
stream turbulence inte~sity ..,...~ 20%
d) air is ~sed as a gas medium
e) an amount of gas to be removed ranges ~rom
8~o ~0 9~o, since a ~ibrous material o~ 105 g/m2
is to obtained from sho.rt fibxes.
~ 'he means for removing a part of gas ~'rom the gas fibre
strea~ is embodied as a plurali~y of blades formiDg two
vertical rows, each row being disposed u~der one fro~tal
wall of the 510t nozzle. Each blade is inclined relati~e
to the axis of the slot ~ozzle at 10, and each row o~
blades is incli~ed relative to the axis of the slot nozzle
at 11o
'r`he abovementio~ed minimum angle of blade inclination
a~d maximum angle of row incli~ation with respect oto the
-slot nozzle axis are chose~ i~ order to provide an inte~sive
xemoval of gas ~rom the gas-fibre stream as the latter is
movi~g between the rows o~ bladesO
Each row of blades is divided in four sec~ions. The fi~st
three sectionsg as view~d from the nozzle~ are of the same
29 :
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. . ' .. . .. ` ... ;.. ,;~. ` ~ .
.. ~ . . . . ~ . -.... : .
....
2~ -
length~ ~he length o~ the f`ourth section is e~ual to 1.2 timesthe le~th oX the first sectio~. ~'he Lap between the blade~
over the first section is equal to 12 mm, kh0 gap between
the blades over the second section is equal to 8 mm, tha
gap between the blades over the third ~ect:ion is e~ual to
6 mm9 and the gap between the blades over t;he fourth section
is equal to 3 mm.
Due to the provisio~ o~ ~our sections, each havi~g a
differe~t gap distance between the blade~ ? a smooth removing
o~ gas ~rom the gas-fibre stream is ensured. ~he loss o:E as- .
bestos fibres including a considerable amou~t o~ small-siæed
fraction, is insigni~icantO 'l'hough the length o~ ~ibres is
~mall, ~he mass o~ the asbes tOS fibres i~ great, therefore,
the gap dista~ce between the blades over the first section
ma~ be set much greater than the fibre le~gthO In this case
considerable inertia forces are developed in the gas-fibres
stream as i-t moves alo~g the bla~es of the first section,
these forces preventing ~ibre loss~
~ 'he gas-fibre stream is supplied to the slot ~ozzle at a
velocity of 10 m/sO Upon leaving the slot nOYJZ1e ~ its velocity
increases up to 15 m/s due to the provisio~ o~ converging
frontal walls. As the gas-fibre stream travels between the
rows o~ bladesg the gas is being partially removed there~rom 9
50 percent of ga~ bei~g removed over the ~irst sectio~ 30 per-
cent9 over the seco~d section9 15 percent9 over the -third
-- ~0 --
, -:
, :
~ 2~
section, a~d 5 percent, over the fourth section~ '~he total
amount of gas partially removed from the gas-fibre stl~am is
taken as 100 pexcent~ The gas removed from the gas-,~ibre stream
is delivered from the chamber thlough bra~ch pipe~ to the
means ~or dispersi~g fibres i~ a gas stream. r~he total fi.bre
105s does not exceed 10 percent~
As a result o~ removing from 80 to 90 .percent of ~as,
~ibre co~ce~tra~ion in the gas fibr~ stream is brough~ up
tO 250-500 g/m3, ~Ihile the transv~rsal pul~ations charactexi~
æed by the c~o~s-st~eam component of gas-fibre stream turbu-
lence intensity, fall to 5-8 percent, this enabling a gas fibre
stream homoge~eous structure to be obtained.
~ he gas-fibre stream moving with a velocity o~ 15 m/s is
~urcher supplied onto the flat screen traveliing at the same
velocity. 'llhe remaining part of gas ra~ging betwee~ 10 a~d
20 perc~nt is removed by means o~ a suction box, thus foxmi~g
on the flat scree~ a ~ibrous la~ex having c~ ass of 70 g/m2.
The ~ibrous la~er is then subjected to impregnatio~,with
3% silico~ emulsion to ob~ai~ a material having a mass o~
105 g/m2, rolli~g and dr~i~g to achieve the humidity o~ 2 per-
cent. A finished sheet material possesses high -thermal a~a
electrical lnsulation proper-ties and ca~ be advarltageousl~ ~
used in electrical engineeri~gO
Example 2
~ heet material ha~i~g a mass of 110 g/m2 is to be produced
fxom sulfate bleached cellulose~ fibxe mode~length bein~
of 175 F~ o
, - 31 -
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2 ~
a) fibre concenGra-tion i~ the gas-fibr~ stream ~. 50 g/m3;
b) as a gas medium ai.r is used, contai~ing 10 perce~t
carbQne dioxide additio~ to prevent e~plosion o~
gas-~ibre mixture under the actio~ of static elect-
ric charges;
c) velocity o~ the gas-~ibre stream ~ 300~ 8 m/s;
d) crosswstream compone~t of gas-fibre stream
turbulence intensity .~ .-0. J ~ 0 25Yo
The amou~t of gas to be preremoved ra.~ges between 60 a~d
80 percent 9 since the material havi~g a ma~ o~ 110 g/m2
is to be obtai~ed.
The means ~or removi~g a part of gas from the gas-fibre
stream is embodied as a plurality o~ blades ~oxmin~ two verti- .
cal rows, each ro~ being ~isposed under one ~ro~tal wall of
the slot nozzle. Each blade is i~cli~ed with respect to the
axis of the slot nozzle at 10, and each row of blades is
i~clined with respect to the axis o~ the slot nozzle at 305. ~ .
The abovementioned mi~imum a~gles of incli~atio~ of each
blade a~d of the row of blades relative to the axis of the
slot ~ozzle are chosen in order to provide an inte~siv~
removal o~ gas from the gas-~ibre stream as the latter moves
between the rows of blades~
~ ach row o~ blades is divided i~ three sections of the
same le~gth~ ~he gap distance bet~een the blades over the
first section lS equal to 1~ mm9 the gap distance between
~ 32 -
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~8~
the blades ove.r -the second section is equal to 9 mm~ and the
gap dis~ance be-tween th~ blades of the third section is e~ual
to 4 m~.
Cellulosic fibres have a~ amoun-t of small-sized fractio~
less tha~ the asbestos fibres have~ hence i.t is su~ficient
to di~id~ tha ro~s o~ blades only into three sections and
to car.ry out the removal of gas with less smooth~ess.
Blade~to~blade gap distances over each sectio~ ensure a~ -
inte~sive removal of gas without co~siderable fibxe loss.
~ he gas-fibre stream i~ supplied to the slot nozzle at
a velocity of 8 m/s. Upon leaving the slot nozzle, its velo-
city increases up to 10 m/sO As the gas-fib.re stream travels
bet~leen the rows of blades, the gas is being partially remo- -
ved thexefrom, 55 percent of ~as bein~ removed over the first
sectio~ 30 perce~t of gas being remoYed over the seco~d
section, a~d 7 percent of gas beinO removed over the thixd
section. '~he total amount o~ gas bei~g partially removed ~rom
the gas-fibre stxeam is taken as 100 percent.
~ s a xesult of removing o~ 60 to 80 perce~t of gas,
fibre concentration i~ the gas-fibre stream is brought up to
125-250 g/m3, while the tra~sversal pulsatio~s o~ the gas-~ibre
stream ~all to 4-6 percent, this enabli.ng a gas-fibre stxeam
of homoge~eous structure to be obtained
The gas fibre stream moving with a speed o~ 10 m/s is
further swpplied o~to the ~lat ~cree~ trave~ling with the
. .
33 -
~ ~ 5~ 2 ~
same speed. The remaining part of gas rangirlg from 20 to 40 per-
cont is removed by means of a suctio~ bo~ thus ~ormin~ on
the flat screen ~ layer of cellulosic fibres, having a mass
of 90 g/m . The fibrous layer is impregnated with 3% solution
of modif`ied mai~e starch to increase the mass of the material
up to 110 g/m2 7 and then is subjected to rolling and drying,
~vhereby a wrappin~ paper is obtained.
Example 3
Sheet material having a mass o~ 40 g/m2 is to be produced
from ~iscose fibres, fibre mode length bei~g of 8 mm.
a) fibre concen~ration in the gas fibre
stream ~ -O---O~ --------O~ 25 gfm3
b) air is used as a gas medium
c) velocity o~ the gas-fibre stream 0.Ol....... 6 m/s
d) cross-stream compone~t of gas-fibre stream
turbulence intensity ...... 0....... O~.... O 3&~o
~`he amount of ga~ to bs prexemo~ed ranges between 50
and 60 percent, since viscose ~ibres are lo~g a~d since the
material of L~0 g/m is to be obtai~edO
The means for removing a part o~ ~as from the gas--~ibre
strea~ is embodied as a plurality of blades forming two
vertical rows, each row being disposed und~r one of the fron
tal walls of th~ slot nozzle. ~ach blade .i5 inclined relative
to the axis o~ the slot ~ozzle at 15~ each row o~ blades
being inclined relative to the ~xis of the slot ~ozzle at 7O
.,,
, ! , , . . ' ;
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~085~28
Si~ce the ~iscos0 fibres do ~ot posse9s adequate resilien-
ce7 an i~clinatio~ of t~le blades with respect to the axis of
th~ slot noæzle at 15 provides ~or smooth slip~i~g of fibres
~long~ the blades 9 while a~ incli~ation of the row o~ blades
relative to the axis o~ the slot ~ozzl~ at 7 ensures modera-
te i~tensity o~ gas removal f`rom the gas-~ibre strGam~
Each ro~J of blades is divided i~to two sectio~s of the
same length ~lade-to blade gap distance over the first sec-
tio~ is equal to 10 mm9 the gap dista~ce betwe~n the blades
o~er the seco~d section is equal to 5 mmO ~ -
The gas~ibre str0am is supplied to tha ~lot ~ozzle ata velocit~ increases up to 8 mJs As the gas-~ibre stream
passes between the rows of blades~ the gas is partially re-
moved therefrom? 60 percent o~ gas being removed over the
first sectio~, and 30 perce~t o~ gas being removed over
: . the.second section. The total amount of gas preremoved from
the gas-fibre stream is taken as 100 percent.
As a result o~ removing ~rom 50 to 60 percent of ga~
fibre conce~tratio~ i~ the gas-~ibre stream i~creases ~rom ~.
25 g/m3 to 50 - 64 g/m3, while the tra~sversal pulsatio~s
of the gas~ibre stream fall., due to contracting of the
stream, to 7 percent, thus providi~g for homogeneous structure
of the gas fibre stream.
~ he gas~fib~e stream moving with the speed of 8 m/s is
supplied onto the ~lat scree~ travelli~g with the same speedO
.,~ '; ~`~.
;; ' ~ '
. ~ . '
!, .
'' . ~,. , ., ' . . . ' ,', : ,
~ ~ 5~ ~ 8
The xemai.rlin~ part of ~as, xan~ing ~ro~ 40 to 50 percentg i~
removed by means of a suc~ion box, thus ~ormi~ o~ a ~lat
screen a layer of vi~cous fibres, having mass o~ 30 g/m2,
which i~ then i~pr0~rnated with 15% water~polyvinyl acetate disper~
sion to i~crease the mass of the ~i~ished ~aterial up to
40 gjm2. ~he ma~erial is subjected to rolling and drying to
produce a no~woven oil filtering material for large-scale
diesel engines. ~.
~J~a~pl e L~
Sheet material having a mass o~ 20 g/m2 is to be pro-
duced Prom polyester man-made ~.ibres of 28 mm mode-length.
a) fibre concentration in the gas-fibre stream ..0 8 g/m3;
b) ionized air stream is used as a ga~ medium;
c) velocity of the gas-fibre stream .. ,~.......... Ø.. ...7 m/s;
d) cross-stream component of gas-~ibre stream
turbulence i~tensity ...... 0.~.......... ~O... ~. 35%~ The amount of gas to be preremoved ranges ~rom 20 to
25 percent, ~i~ce a fibrous sheet mate~ial having a mass o~
20 ~/m is to be produced.
The means ~ox removi~g a part of gas ~rom the gas-~ibre
stream is made as a plurality of blades forming one ~ertical
row disposed under one of the ~xontal walls o~ the slot ~ozzl~0
Blade~toblade gap distance is equal to 20 mm. Each blade is
inGlined relative to the axis of -the slot nozzle at 35~ while
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the row of blades i5 inclined relative to the axis o~ the
slot nozzle at 3-5O
'rhe abovementio~ed angles o~ inclirlatio~ of each blade
and o~ the row of blades with respect to the axi.s o~ the slo~
nozzle are chosen to ensure a removal o~ small amount of gas
essentiall~ without fibre loss.
~ he gas-fibre stream is supplied to the slot ~ozzle at
a velocity of 7 m/s. ~pon leavi~g the slot nozzle, its veloci-
ty is as high as 10 m/s. ~s the gas-fibre stream travels along
the blades, 20 percent of gas is removed theref`rom. ~5 a result
o~ remo~,ing of 20 perce~t o~ gas, fibre conce~tratio~ i~ tho
gas-fibre stream raises from 16 g/m3 to 21 g/m30 ~he cxoss-
streRm component of the turbulence inte~sity falls, due to
gas-fibre streRm contracting, to 12 percentO
'rhe gas~fibre s~ream moving with a speed of 15 m/s is
supplied onto the flat screen moving with the same speed. ~he
remaining paxt o~ gas~ namely 80 pexcent o~ gas, i~ rjemoved
~rom the gas-~ibra stream by means of a suctio~ box, thus
forming a layex of man-made fibres, having a mass of 15 g/m2O
1'he layer is impregnated with 5% solution of poly~i~yl alcohol
to obtain a material havi~g ~ ~ass of 20 g/m2~ which is then
subjected to rolling and drying. ~`he finished material is
a long grai~ paper practicable in electxlcal e~gineering.
~ xample 5
Sheet ~aterial ha~ing-a ~ass of 50 g/m2 is to be prod~lced
~from defi~red wood ~ibrous particles.
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a) fibre co~centra-tion of th~ ga~fibre stream ~ 50 g/m~;
b) veloci-ty of the ~as-~ibre stream ..~0O.,O..,... 8 m/s;
c~ cross~stream compo~ent of the turbulence in-
tensity .~0.,..,...,O~O..OOO...OO..~...O.~..u 32%
d) air is used as a ~as medium;
e) an amount oP gas to be removed ranges from 85
to 90 percent, since a ~ibrous material h~ing
a mass o~er 100 g/m? is to be produced.
The means ~or removi~g a part o~ gas from the gas-~ibre
stream is embodied as a plurality of blad0s arranged so as
to form two vertical rows, earh disposed ~mder o~e of the
frontal walls of the slot ~ozzle, each blade being inclined
relative to the axis of the slot nozæle at 30, while each
row of blades is i~clined relative to the axis o~ the slot
~ozæle at ~1o
The aboveme~tioned maximu~ angles of i~clination of each
blade a~d o~ each row relative to the a~i.s o~ the slot nozzle
are chosen i~ order to provide an intensive ~emoval of gas
~xom the gas-~ibre stream as it flows betwee~ the rov~s of
blades.
Wood ~ibrous particles used in the proceæs posse~s great
mass and considexable resilience 9 there~ore inertia force~
acti~g upon ~ib~ous material are significa~t.
For the same reason blade~to bl~de gap distances have
the same dimensio~s e~ual to 6 mm. ~he gas-~ibre s~xeam iq
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is fed to ~he slot noæY~le at a velocity of 8 m/s. ~po~ lea~ing
the 510t nozzle the velocity o~ the gas-fibre ~ream increa-
ses up to 10 m/s~
As the stream o~ gas a~d wood fibrous particles flows
be tween the rows o~ blades, a part o~ gas accou~ting ~or
85-90 p~rcent is removed. As a result~ the concentration
of wood fibrous particles is brought up to 334-500 g/m30 Th0
cross~stream compone~t fof the turbulence inte~sit~ fall,s~
due to co~tracting of' the stream of gas a~d wood fibrous
particles, to 7-10 percent.
~he stream is ~urther supplied onto the flat screen i~ a
direction normal to its pla~e. s
~`he flat screen travels at a velocity o~ 0.8 m/s. The
remaining part o~ gas accounti~g ~or 10-15 percent~ is removed
~rom the gas-~ibre stream by means o~ a suction bo~, thus
~orming a la~er of~wood fibrous particles, havi~g mass o~
400 g/m3. The obtained layer is impregnated with a solutio~
o~ a phenolic resi~ so as to bri~g the mass o~ the fi~ished - -'
material up to 500 g/m3~ ~he material is the~ cut into sheets
havi~g dimensions 3~3 m and subjected to pressure o~ 60 kg/cm
during 20 min. at 180C.
'l'ho finish~d mat~rial is a fibrous cohstruction board
practic~ble in co~structio~ ma-terial industry.
Example 6
" ~ .
Woole~ ~elt having a ma~s o~` 400 O/m' is to be produced
~rom ~ibres o~ 10-35 m~ mode~le~th.
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a) fibre ooncentration in the gas-fibre
stxeam .~ ........ D ~ O ~ 40 ~/m3t
b) velocity o~ the gas-fibre stream ~,.,....0 6 m/s;
c) cross-stream component o~ the turbule~ce
intensity ~0%;
d) air is used as a gas medium;
e) the amount of gas to be removed ~,.,O~....~ 90V/o.
~ '~he means ~or removing a part o~ gas is embodied a~ two
rows o~ blades, each row bei~ disposed under one o~ ~he fron-
tal walls of the slot nozzle. q~he blades in each row are in-
clined at 18, each ro~ being inclined at 11~
The abovementioned angles of inclination of the elemen~s
are chosen with xegard to the mass of eleme~tary ~:ibres and
their resilience~ ~ince the fibres are long and posses~ a
considerable mass, an intensiYe removal of gas i~ allowable.
1'he resilience of the fibres is ve~y hi~h, there.~ore the
angle of inclination of the blade is set 18.
Gap distances betwee~ the blades are the same and equal
to 10 mm, since the mass of each ~ibre is su~ficient to
ensureS un,der the actio~ o~ inertia $orces, a high velocity
transversal flow of gas being ~emovedO
The stream of gas and woolen ~ibres is ~ed to the slo~
~ozzle with a speed o~ ? m/s. Upon leaving the slot ~ozzle
the stream moves at a speed o~ B.5 m/s and is channelled
between to rows o~ blades~ ~s the stream flows between two
~ ~
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row~ of blades, a~ amount o~ gas accou~tin~ for 88-90 pex-
cent is being removed. 'l'he co~ce~tration of fi.bres in the
gas-f`.ibre ~tream is brought up to 410-500 g/m3. A paxt of
gas removed, the ~as-fibre stream is supp:lied onto the flat
screen with a velocity of 8.5 m/s at 120 with re~pect to
its planeO q'he flat screen moves at a velocity of 1.35 m/s9
the remaini~g part of gas is removed by mea~ of a suction
boxO
As a result, a layer of fibrous material havi~ a mass
of ~0O g/m2 i~ formed o~ the screen.
The obtained layer is subJected to rolli~.
The finished material is a Pelt u~ed in te~tile and
construction material industries.
While particular embodiments o~ the inventio~ have been
shown a~d described in detail, various modificatio~s thereo~
will be appare~t to those skilled in the art and there- -
fore it is not i~te~ded that the inve~tio~ be limit~d to the
disclosed embodiments or ~o the details the~eof a~a the de
partures may be made therefrom withi~ the splrit and scope
o~ the i~ventio~ as defi~ed in the claims.
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