Note: Descriptions are shown in the official language in which they were submitted.
l)HVlt~ uLLl~uN l~ltL~I. Sl.~ 4 4Ylab ~ 14
~_~d~ 8~361
A PROCESS AND APPARATUS ~OR APPLYING ~ONDING ~E~T
AND A PROC~SS FOR FORMING RECONSOLI~A~ED
WOOD PRO~UCT
~hi~ invention rela~es to 8 proCess and
apparatus for appl~ng bonding agent and to a pro~ess
for ~orming a reconsolidated wood product as well as
to a recon~olidate~ wood produc~ ~ormed ~y ~he latter
5 ~rocess.
Australian Patent ~p~ ication 510,845
describes a reconsolidated wood product eorm~d from
at l~ast one ~lexible open lattice work web of
naturally interconnected wood strands generall~
10 ali~ned along a ~ommon grain direc~io~, a su~stantial
proportion of the strands ~eing ~bst~ntially c
di~cret~ t incompletely separatQd from each
other,and the web having been conso~idat~d by
co~pres~ion wh~lst ~ubstantially main~a~ning the wood
15 strand~ aI~gned along the ~ommon ~r~ln direction and
. . . ~
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~1 2~78~
the strand~ being bonded together to hold them in
juxtapo~itionæ a~umea p~r~uant to the consolidation.
That p~ten~ sp~cific~t on al~o de~cribes a
pro~e~ ~or form~ng a recon~olidatea woOa proauct
from a fl~lbl~ opsn latt~ce work web of natur~lly
~n~e~conn~cted woo~ ~trands, ~h~ we~ being forme~ by
p~rtiall~ rending n~tur~l wood ~o that the s~rana~
are qeneral~ aliqned along a common grain ~irection,
a substantia~ proportion of the strana~ being
~ubstantially ~i~crete but incompletely sep~ra~ed
f~om ~ach other, ~nd the proceYs ~ompri~ing
comp~ssinq the w~b to consolidate the st~an~ whilst
m3int~ining them 5uch a~ to ~ubstanti~ly e~tend in
the ori~in~l grain direction and bond~nq the strands
to~ether to ho~d them in ju~tapositions as~umed
pursuant ~o the consolidation.
One~f the dif~iculties associated with the
proces~ of Austr~lian P~tent ~pecifica~ion 510,84$ i5
sati~factorily introducin~ the bondinq agent to the
web of naturally in~erconnected wood strands. That
p~tent speciÇication proposed introducing 3 oamed
~onding aqent to the compre~ion mould or spraying or
otherw~e applying the bondinq agent during or aft~r
the ~ormation of the web, but a p~rticularly
pre~rred proposal was to dip the web into a ba~h of
l~qu~d re~in.
It has ~een ~ound to ~e p~rticularly
i~portant in the formation of a reconsolidated wooa
produc~ o~ th~ type disclo~d in Au~tralian Pat~nt
30 ~pe~ific~tion 51~,845 to en~ure that the bonding
~gent is thoroughly disper~ed through the web.
Accordinq to the present inYention there i8
proYide~ a pro~e~ f~r spplyln~ ~onding agent to a
fle~ible open lattice work whb of naturallY
C ' ' ~ W~ I JIJI 1 1 I~I_D . ~11~ O~ JO r . ~
7~3g61
interconn~cte~ wooa ~trand~ prior to compressing and
con~olidating ~aid web ~o form a recon~ollds~e~ wood
product, said wub bein~ forme4 hy partially ren~ing
n~tura~ wood ~o ~h~t ~aid str~nds a~e genera~ly
align~d along ~ common g~8in ~irection with a
subst~nti~l proport~on of ~a~d ætrands b~in~
sub~tanti~lly ~i~crete but inaompl~t~ly 8~parated
from ~ach other, said pro~e5s compri~ing pa8Bing the
we~ through a p~r o spplying rollcr~ of wh~ch at
lea~t one roller is aorru~ate~ whereby a por~ion o~
the web pas~in~ through the applying ro~le~ at any
on~ tim~ pr~d ls~erally without substantial
further ~p~at~on of the ~rands, app}yin~ bonding
agent to ~3i~ portion of the web immadiately prior to
its pa8sage through the pair o applying roller~ or
while the portion i~ spread by the pair o~ appl~ing
roller~ and re~oving e~ces~ bonding agent from the
web ~ownstre~m o~ ~aia appl~ing roller pair, for
e~ample by means of a pair o~ squeeze roller~.
Further accordin~ to the present invention
there i8 ~rnvided apparatus ~or applying bon~ing
: aqent to a fl~ible open lattic~ wo~k web o
na~ur~lly interconn~cted wood ~trands formed by
partially rend~ng natural wood ~o that said strand~ ~
are gener~lly ali~ned 810ng a common grain direction
with a ~u~st~ntial proport~on o~ ~aid strand~ being
~ub~t~ntially d~rete but Incomplet~ly separatea
rom each other, ~aid apparatus compri~ing a pair o~
applyin~ rolle~ adapted to recei~ the web
therethrough, at least one of the roller~ of said
pair having a corrugat~d outer ~urfaae whereby to
de~ine an e~ten~ed path ~or ~he web acro~s the width
thereo~ and to thereby open th~ web, mean~ fo~
~pplying bonding ~gent to ~ por~ion of the we~
6~L
imme~ist~ly upstre~m o~ ~he 3pplying roller p~ir or
to the open0d po~tion of the web, and a pai~ o
sque~ze ro~ler~ for removinq ~c~s~ bon~in~ agent
f~m the web.
By the ~re~ent invention, we have found that
the lattice o the we~ ~s res~liently opensd up a~
the w~ pa~es ~hrough the applying roller pair ~ue
to the ~ncr~dssd lat~r~1 p3~h A~f~ned ~y the or ea~h
eorruqa'ce~ roll~r, th~t i~ th~ tncrea~ed sur^face
len~th of the roller in the axial d~rection thQreof.
The bond~n~ agen~ may accorBingl~ more readily enter
the body sf the ~b on~ coBt the etrsn~. It 1~ not
nece~sary Por the ~e~ to be ~ubstantially compressed
between th~ nip ~ the applying rollars, ~erely that
its efective ~urace area be increa~e~ by ~ollowing
the con~ou~ of th~ or each corrugat~d roller.
It ~ preferred that hoth roller~ of the
applying roller pa~r are aorrugated in wh~ch c~e the
peaks of th~ respecti~e rolle~s ~houl~ be of~et, and
may int~rme~h, to de~ine a sinuou~ path between the
applyin~ roller~ which i~ of greater len~th than the
- a~ial length of the rolle~. As noted previously the
nip between the rollers nee~ not be ~ubstantially
smaller than the dep~h of the we~ sin~e it is
impo~tant not to furthsr b~eak up the web by
additional ~eparation of the strands. The
corrugations may take any de~ir~d ~hape ~d ara
conveniently sub~tsntially si~u30id~1 or sinusoidal
but with lanas between ~he peak~ (i.e. ~he valleys
are extended)~
Ths applying rollers may take any suitable
~orm ~nd be ma~e of, for e~ampl~, me~al, rubb~r or
plastics, Ca~t iron, ~tainle~s teel and alumi~ium
are p~eferred metal roller m~terial~. Alte~na~ively,
CC ~ I~ ' 1C LJnV 1~ ~ UL~ I ~Ul`I I ICLD . C~ ) O~C~
~LZ7~3~6~1L
the or ea~h applying roller ma~ be pn~umstic, and it
i preferr~d tha~, where only one of the roll~r~ in
the roller p~ir i~ corru~ated, at lea~t ~he other ~5
pneumatic .
A ~e~ond pair o applying roller~
inaorporatiA~ ally one or more of the aforem~nt~oned
features m~y be provl~d up~tream or down~tr6~am of
th~ first m~ntioned pair to ~acilitate in~iltration
o~ the bon~ing a~e~t to the l~tti~e work. Th~
~pa~ing b~'cween 'chf3 ~wo pa~rs of spplyin~ roll~r~ may
be min~mal, for esample in the r~nge o 25~100 nun or
le83, pr~erably towar~s ~he lo~er end o~ the r~ e.
A sUPport rolle~ or other ~upport me~n~ may b~
provided b~twe~n th~ two pairs of applyin~ rollers,
The n~p between the roller~ o~ the two pair~ of
~pplyin~ rolle~s may be ~ub~tantial~y the sam~, bu~
mo~t ~dvantageou~ly the nip betwe~n th~ downstr~am
pal~ o~ ~pplyi~g roller~ is slightly ~malle~ than
that bet~een tho up~r~am pair. In a pre~rred
embodim~t whe~ our applyinq roller~ ar~
corrug~te~ the ~piceg o the peaks of the up~tream
pair o applylng rollers l~e in a common plane in the
nip, wh~le ~he apices of the pea~æ of ~he down~tr~
paix of ~pply~ng roller~ intermesh in the nip.
~he or each pa~r of applying rollers may ~e
d~iven or non~driven, or one of the two pairs may be
drivQn. If nona of the appl~ing roller~ iB ~riYen it
will be ne~essary to provide other mean~ for
displacing the web therethrough. ~dvanta~eou~ly,
p~ir of cyl~ndri~l driv~ roller~ i8 provided
upstre~m of the one pair or both pairs o~ applyin~
roll~r~ whether or not th~ appl~ing rollers ar~
driv~n, and ~upport ~an~ or example in the form o~
a single roller m~y b~ provided to guide the w~b from
JtlVIG~ 0~ ~_U--LI~JIY l'l~LC. Dl.~ b~ 4~WC 1~
~Z~7~
the ~ri~e roller~ into the nip o~ the on~ pair or
upstre~m p~ir o~ applyin~ roller~.
The m~an~ ~or remo~ing e~cQ~ bon~in~ age~t
from the web may take any suitable form, but ~æ
S indi~ated here$nbefore p~e~ly compr~e~ a p~ir of
~quee~e rol1er~ whch are conveniently fo~med o~
rubber or ar~ pneumatic. Such squee~e roller~ are
pr~ferabl~ plain ro~le~ and may be mounted in
floating msnner. ~he combination of at least on~
corrugated applying roller an~ the s~ue~e roll~r3 is
a~apted to 3uccessi~ely compres~ and relas the web
prima~ily o~ sub~tantially in the direction o ~he
depth t~er~of and to permanently ~na~ea~e the width
of the w~b without bre~kin~ th2 lattice-continuity.
I~ ha~ be~n found that deorming the web by me~ns o~
the ~ le~t one corruqatsd applying roller such ~
to increase the width o the wsb in the rang~ 1~ to
35~, preferab~ about 25~ i~ æsti~factory ~or webs
! f~rme4 rom young pinu~ radiata trHe~.
A ~upport roll~r or other carrier mean~ may
be pro~i~ed ~etween the one applying roller pair or
~he downstrea~ applying rolle~ pair and the mean~ ~or
- r~moving exce~ bo~ding aqent. Such carrier means
and the aforementione~ other optional ~UpPort mean~
a~e all intend~d to prev~n~ ~mall ~eparated strands
or splint~rs ~rom ~eparating from the w~b, but where
they ar~ in the form of roll~rs, and particul~rl~ ~f
the bon~ing 3qent is 3pplied as a ~oam, they may al~o
~erve the ~unction o~ a~sisting to return e~ce s
bonding a~ent to a position up~ream of the one pair
or ~h~ up~tream pair of applyi~g rolle~s for re-u~e.
A shroud ~t lea~t ben~ath the one pair o~ e~ch pair
of applying roller~ may be provided to a~ t ~h~
retu~n c~ the e~ces~ ~onding age~t to a po~tion
__
VI~V l e ~ ULL I ~UI`I IYI~L~ 4 4Yla~
~7~396~
upstre~m of ~h~ applying ~ollers, a}thou~h e~cc~s~
bon~ing age}lt ma~ also be carried back o~rer the top
o the ~pplying rollers ~y the rotating a~tion
thereo~ .
~he bondinq agent ma~ be of any ~uit~le
Sype, that c~n be readily infiltrate~ in~o the w~b.
For e~:ample a resin agent ~uch as ta~nin may be
disso~ved in w~t~r and applied as ~ liquid either by
imm~rsion, or br f lo~ through ~ cur~in, or sprayed
wi'ch ~ir un~er pre~ure, or the liquid may be PoAmed
with ~ir or ~ther ~as and the oam ~n~iltrat~d into
the ~arim ~eb. The bond~ng agent ma~ be metered o~to
the we4 on either or both ma~or sura~ up~traam o
the or each corxu~ated roller pair where it is
lS carried orw~rd into the nip of the rollerg ~nd
worked into the ~erim web. Alternat~vel5~ th~ ~onding
agent may b~ applied to t:he applying roller¢ ana be
carried by them into contact with the scrim w~b.
~ Alt~rnati~ely again, the bonding agent may be applie~
~o to u bsth between ~he one pair or tbe dow~tream pair
of appl~in~ roll~r~ and the mean~ for remo~in~ e~c~
~ bonding ~ent, and he carried up~tre~m ~r th~
~tating ~ctio~ of the applying roll~r~.
hhen the bonding agent solution ~or
emul8~0n) i~ a~plie~ as a foam, the ~oam ma~ h~vs a
density o the or~er o~ lO0 g~litre, However, ~he
proces~ ha~ ~e~n operat~d ~ati~fac~orily with a foam
dansity in ~he range 30 ~1 to l~0 g/l and h~avier
den~tie~ may b~ con~idered ~or ~pecific
applioations, Foam den~ity controls the pick up of
resi~ and moi~ture if it is a solution. It i8 al~o
anticipate~ tha~ oam~d liquid ~sin~ ma~ be u~sd
neat.
Compression 2n~ consolidation of th~ web,
39~;1
for ~xample by curing the bond~ng agent while the w~b
is compres~e~ on a non-, ~emi- or fully- continuous
basi~, occurs ~ownstream o the ~pplication of
40nding ~ent, Two or more ~f th~ we4~ may ~e
~uperpo~ed prior to compre~sion and consolidatio~.
~ urther acc~rding to the pr~sen~ inv~n~ion
therQ i8 provided a proces6 ~or ~orming ~
recon~olidated woo~ produ~t from a plurality of
sup~rpo~ed ~le~ible open latt~ce work webs of
naturall~ inter~onne~te~ wood strands, each o~ said
webs being ~o~mod by ptrti~lly ronding natural wood
~o that ~id ~trands ~he~eo are generally ali~ned
along a common grain di~ection, a sub~tantial
proportion oF said ~trands of ea~h we~ bein~
sub~tantially ~iscrete but ineompletely separste~
~rom ~ach other, said proCess ~ompri~in~ applying
bonding agent to ~ai~ webx, ~uPërPosing th~ webs,
compre~sinq the ~uperpos~d webs to con~olidate th~
stran~s and curlng the bonding agent to bond the
20 8tr~nds and ~ebs together, ~aid applic~tion of
bon~ing a~ent compriEing pa~sing each wob ~hrough a
pair of ~pplying rollers of which at least one roller
is aorrugated whereb~ a portion o the web pa~sing
throu~h the roll~r~ at any on~ time i~ 8p~ead
25 later~l~y without ~ub~tantial furthe~ sepa~ation of
'che strandg, applying bonding apent to ~aid portion
o~ the we~ ~mlnedia~el5~ prior to its paæsage through
the pair o~ applying roller~ or while the portion
spread ~ th~ pa~r of ~pplyinq roller~ and removin~
30 e~ccess bonding agent from the web down~t~e~m of ~aid
ro 1 ler pai r .
Still furth~r ac~ording to the present
~nv~ntion there i8 proviae~ a reconsolidated wood
product orn~e~ by the proce~ ~escribed in the
1Y:5 ~ 14 IJHVlt~ ULLl~iUN MtL~. 61~ 654 4906 P. 12
96~
i~me~iate1y preceding paragr~ph.
rwO embo~m~nts o~ apparatus ~nd a proces~
in a~cord~nce with the invention will now be
deRcrib~d by way of e~ampl~ only w~h reference to
the accompanying ~rsw~ngs in which:
FIGV~E 1 ig a disqram æhow~ng the steps in
procsssing re~on~oliaate~ wood products ~n ao~ordance
with the invantion de~Gri~ed in ~he aforementioned
Au~rali~n pat~nt sp~c~~cation 510,845;
FI~URE 2 ~ ~ s~hema~ic diayram o~ one
embo~im&~t o~ app~ratus u~ed in practl~ln~ the
pro~es~ of the pre~ent invention;
FIaURE 3 i8 a ~ectional sids Yiew of a
second em~o~ime~t o apparatus u~ed in practi~ing th~
proce~ of the present invention; and
FIGU~E 4 ~ a ~ragmentary side Yi~W of an
~pplying rollèr of the ~pp~ratus in ~igure 2 or
Figure 3.
Refer~ng fir~tly to Figure 1, in the
proceg8 of Au~t~alian Patent Sp~cification 510,8~5
natural wood logs 10 ar~ first par~ially broken down,
being pa~sed sucae~sively ~etwe~n ~ollers 12 o~ one
or more roller p~irs to induce ~racking ~nd ~hence to
progres~ively open up the lo~ ~tructurs to form it
25 int~ a we4 o~ lo~sel~ interconneated splintar-lik~
strand~ (calle~ "splinters" in Patent Sp~cification
510,~45), The resultan~ web, shown at 14 in ~igure 1
is o fl~ble open lattice work ~orm, with
individua~ str~n~ ~eing connected ~o each other and
3n m~in~aining th~ original ~ra~n directlon of th~
wood. A~he~ve i~ ~hen applied to th~ web3 14 such
a~ by imm~r~ion in a suitable liquid adheslve in a
bath 1~ as ~hown. A~ter removal of OExce~s adhqsivs,
~or example ~y allowing the webs to drip, a plural~ty
17ti (~ L~ l)~ C~ ~ ~,JLL I :~UI`~ l~ltLI:~ . bl~ b~4 4~1~1b i' . 1~
3961
of we4~ 14 ar~ asgemble~ to~ether, such a~ by la~in~
th~m one ov~r the other in ~ suit~bl~ mould 18. ~he
aseemblage of o~erl~i~ we~æ 14 ~ th~n compres~e~ in
mould 18 ~uch B~ ~y compr~ssion betwee~ th~ bas~ of
the moul~l ~n~ an upper pres~ elemsnt 20 ~ ~hown,
and the adh~s~ve is cur~d, to form the ~inal produçt
2Z.
Produc~ 22 i~ ch~racterised in that ~t
comprises a plurality o~ woo~ ~trands whlch remaln
na~urally inter~o~nect~d and wh~c~ e~ten~ ge~erally
in the origin~l qrain d~rection o~ ~he wood. The
st~ands are boun~ to~ether by the adhssi~e bu~ are
po~itioned in ~omewhat displa~ed relative locatio~s
as compared w~th the position~ occup~ed ln th~
ori~inal ~og 10. ~he p~oduct 22 ha~ been found to ~e
particul~rly satifi~actory as it posse~se~ good
mechanical properties, due to the reratively 3mall
degradation o~ the oriqinal wood ~tructure which i8
caus~d b~ the p~ocess, as well as good n~ilability
and a ~enerally pleasing appearance.
The proce~ immediately before ~e~cribed is
: a batch type proce~s and Figures 2 to 4 i~lustrate
schematic~lly two ~mbodimen~s appara~us for applying
bonding aq~nt t~ one o~ n o~e webR 14 ~y ~
~5 ~emi-~ontinuou~ or continuouR proc~ss in accordance
with the pre~ent in~entio~.
Refsrring now te Figure 2 apparat~s 24
comprises a fir~t pair of app~ying roll~rs ~6 and ~
second pair o rollers 2~ each mounted for ro~a~ion
3Q about an a~is transve~e to the direction of
di~plsc~me~t o~ the web 14 through ~h~ apply~ng
rollers, ~hown by the arrow 30. The roll~ 2~ and
~ m~y ~ach b~ dtiven or non driven ~nd in t~e
prefe~r~d app~ratu~, ~11 of th~ applying rolle~ are
Jlt~ ULLI~UN MELB. 613 654 4906 P. 14
~ 1
driven to feed the web through the ~ppa~atu~ 2~. Tha
roller~ n~ay b2 mounted in a ~l~itable frame or hath
whieh ~or con-~enience ha~ not been ~hown.
E~ch of the rollers 26 and 28 ha~ the ~orm
5 ~hown ~n ~gure 4, th~t i~ witl~ a ~eml~inusoidal
outer periphery wi~h peak~ 32 interspace~ by lands
34, an~ the peaks of e~ch o the pa~r~ o roller~ 26
and 2~ are oset so as to def ine a sinuous path
between the roll~r~ of ~ch pair, ~hst i8 with the
10 pe~ks 32 ~f o~ r~ r Or each pair overlyins~ the
l~nds 3~ of the oth~r roll~r in that pa~r. Each o
th~ rollers ha~ a key~d ~pind:le 36 e~tending ~rom
e~ch end of th~ ~olle~ bod~ and ls preferabl~ ~orme~
in steel or cast ~ ron . In a prefer~ed en~odiment,
15 the ro~lær body 38 has a length of ~out 440 mm an~
th~ peak~ 3~ ~n~ land~ 34 hav~ outsid~ diamet~r~ o~
about 150 and 110 mm re~pectively. ~he typical
length a of e~ch land is ~0 n~n while the radiu~ b o~
the ~pex 40 o~ ~ach peak 3~ i~ typically 3 n~n and ~he
20 an~le a of each pea)~ i~ typically 23. The
preferrsd range of thickne~es or ~Hpths o th~ w~b
14 a~e in tha rang~ 25 to 100 run and the preferred
minim~lm nip (i.e.~ between the planes of th~ pe~ks~
between the rollerg of each p~ir 26 and 28 i~ in the
range 0 to ~0 mm with the nip ~stween the ~ir~t pa~r
o~ ro~lsr~ 26 b~ing advantageou~ly slightly ~reater
than the nip b~tween the second pair of rollers ~8.
The ~epth of the peaks 32 may be in th* rang~ 15 to
25 mm and it will be appreciated that the rolle~s of
30 e~ch pair Z~ 3nd 28 may intsrmesh to a small degree.
Pre~era~ly only ~he roller~ 28 ~o intermesh.
Accor~insly, th~re may be only a ~mall ~e~re~ of
compression c~ the web 14 between eith~r of th~ pair~
o~ rollers 26 ~n~ 2~ ~ut ~he weh 14 i8 ~t~etche~
lY~ VflJI~ ULLI~;UN MELB. 613 654 4906 P.15
~2~39~
12
late~lly, ~long tha len~th o~ the rollars, by
~ollowing th~ llOUS path de~ine~ b~r th~ nip~ S4 ilS
to op~n up the lattice wor~ of the di~ete but not
compl~tely sep~r~ed ~trand~ o tha web 14.
Imme~a~te~y up~tr~am o~ the ~olle~ palr ~6
in Figure 2 i~ provided means 4~ for metar~ng bonding
~genlt onto the ~b 1~ . The means 42 i~ i llu~trate~
sch~mati(:a~ly an~l compri~e~ re~pectiv~ foraminous
tube~ 44 d~f;pose~ above and below the web an~
suppli~d with liqu~d bonding ~ent such ~ a tannin
soïution rom ~ re~ervoir ~not ~hown) 'chrou~h a
me~erinq aevice ~not ~hown) and pipe~ 46. The tube~
44 are ~lo~;e~ ~ each end and hav~ a ~erle~ o hol~s
48, s~ch as ~hown in the lower tube 44 ~ n Fi~ure ~,
ope~ling 'cow~r~3 the web 14. ~he application ~evice
42 m~y h~ modified to disch~rqe foam or vapori~ed
~ bonding asent onto the web 14, The bonding ag~nt
~hu~ ~ppli~d ~o the web 14 a3 o~ immedi~tely be~ore
~he latti~e work of the web ~s opene~ up by the
roller pair 2~, such opening up permittin~ the
bon4in~ agenS to lnfiltrate the lattice work.
~ufflcient ;nfi~tration may oc~ur with jURt th~
roller pair 2~, but the roller p~ir 28 may b~
proY~d~d, ~Qr e~ample 25 mm down~tream o~ ~he roller
pair ~6 to enhance the ~nfiltration in much t~e same
m~nner as the roller pair 2~.
The su~esgive pair~ o~ rol~ers 25 and ~8
may hav~ their pe~ in line ~ut preferably to ensure
optimum di~pla~ement of the ~rsndg o~ th~ web they
30 ar~ r~ vç~1~ displaced ~o that the pesk~ of ~he
~econd roller pai~ are oppo~te ~he valley~ of ~h~
ir~t roll~r pa~r.
A pair o~ xquReze rollers 48 i~ ~ount~ for
par~llel rotat~on to the roll~rs 26 and 28 to r~ceive
~ 1 C ~ 1 1 ' 1 C' U~V ~ U~ I ~UI~ l ICLD . 01.~ D~ IWt r . ll~
78961
13
the web 1~ dis¢harged ~rom ~he secon~ p~ir
o~ roll~r~ ~8 . The ro~ leræ 4~ arc ~hos~m
~ahematic~11y but prefe~ably have a rubber or
pn~umat~a ~Oay 50 whach mAy be plain or ~ently
S cor~uga~d. The ~oller~ 4~ sho~lla compress ~he w~b
~4 withol~t sub~nti~lly ~re~kirA~ the
i~t6~rconn~ct;on~ twe~n the st~nds o~ the we~ ~o as
to s~uee~e ~2CeS~ bond~ng agent ~rom the we~.
It wi ~1 b~ appre~iated that the 40nf~inq
10 ag~nt may be ~Espl~d between th~ Lirst and ge~ond
paia~s o ro11~r~ ~6 ~nd 2~ so ~hat the bondin~ agent
ig appli~d to th~ ope~ ttice work. Particularly,
where the bond~ n~ agent ig in the form o~ a foam, ~or
e:cample a tannin ~olution which iB ~oamed with a
~S ~uita~le activator, i~ has been ~ound th~t bondlng
agen~ applied downstream o~ the ~oller pair ~, or
e~en downstream of both roller pairs ~6 an~ 28, iæ
ca~ried up~tr~am by the ~otatlng gurf~ce~ o~ ~he
roller~ ~o a~ to also be ~pplied to the web upstream
of ~he ~ir~t roller pair 26. Thus, the bon~lng aq~nt
may b~ applied ~irec~ly to the web 14 between the
second pair of roller~ 28 ~n~ the squeeze rollers
here the foamed bondlng agent i~ applie~ in
thl~ manner, it i6 preer~ble that ~he roller 26, ~A
25 an~ 4~ are aiapoæe~ in a bath to contain the ~onding
agent.
~ efOErrlng now to Figure 3, the appa~atus 100
for ~pplying bon~ing agent in much the same ~ay aæ
the apparatus a4 of Figure 2 includes two 6pac~d
pair~ 102 a~d 104 of applylng roller~ whi~h are e~ch
driven ~nd are ~denSical to the roller~ de~crib~d
with re~eren~ ~o ~igure 4 ~D includlng pe~k~ 32 and
lands 34. The ~oller~ are ~upported for ro~ion
~bout respective a~e~ 36 and ~he axe~ o e~ch pair
1gl37-12-Z2 11:17 DRJIES & COLLISON 11ELB. 613 654 4906 P. 17
39~L
1~
102 and 104 iB vertically ~pa~ed. The peak~ ~ of
the roll~r psir 102 proje~t into a common plane at
the nip 106 80 do no~ in~erme~h while the pa~kæ of
roller pair 104 do intermesh ~lightly a~ shown at the
nip 108. ThQ ~eakR 3~ of the applying roller~ in
each pair are of~et one relative to ~he othe~ and
the peak~ o the rollers ~02 are off~at relati~e to
the pe~ks o~ th~ rollers 104. The bottom roller~ in
each pair 102 ~nd 104 rotate in a clockw~se ~ csion
wh~e the top ro~lers in each pair 102 and 104 rota~e
in ~n ~nti-cloc~w~e ~irec~ion æo as ts disp~ace a
web through th~ nips 106 ~n~ 108 from left ~o right
in ~he dr~wing
Up~tream of the rolle~ pair 10~ i~ a pair o~
lS drive roll~r~ 110 which are ~lain and supported for
rotation d~out a~iæ 11~ to define a nip 114 which
lies in a Common plane with the nip~ 106 and 108~
~he ~ri~e rollers 110 a~e driven to rotate in the
same re~pective directions a~ the roller pair~ 10~
2~ and 104 ana ~re intende~ to force the web into the
nip 1~6.
~ tween the pair of dr~ve rollors 110 a~d
the p~ir of a~plyinq roller~ 102 thare i~ æuppo~ted a
~upp~rt rollar 116 for ro~ation about an a~i~
pa~ l to the a~ec 36 a~d ~12 but below the plane
of ~he nips 114, 106 and 108. ~h~ suppor~ roller 116
is spacea fsom the lower drive roll~r 110 and the
lower applying roller 102 by approximately 5 mm and
may have a diame~er in the range of for example 50 ~o
70 mm. The primary purpofie of ~he support rolle~
i~ to prevent ~mall ~epara~ed ~r~n~B from drop~ng
out of ~he we~ ween tha roller pair~ but i~ ha~ a
~econ~ary function which will be de~c~ibed in due
course.
JHVIt~ ULLI~UN l~ltL15. bl:5 b~4 4YIC11~ 1'. 1~
~ ~'7~9fi'1
Downstr~am oF the applying roller pair 104
is a pair o ~queez~ rollers ll~ which are ~180
dri~en to rotste about r~spective a~es ~20 p~r~
to the ase~ 36 and 112 ~o that th~ nip 122 l~s ~ n
5 the com~on plvn~ of the nipg 106, 10~ an~ 114. ~he
squeeze rollers 118 are al~o ~riven to rotat~ in the
~ame re~p~ct~v@ dire~tion~ ~ the apply~ng roller8
an~ th~ drive roller~ nnd may otherwi~e be ide~tical
to tha ~qu~e~e roll~r~ ~8 ~o w~ll not ~e ~escrlb~d
0 further.
A second support xoller 124 i~ mounte~ ~or
rotation about an axi~ p~rallel to the other
de~cribed ~es and below the plane Of th~ nips. ~he
~upport roll0r 124 ~a~ hav~ a ~iameter in the range
50 to 70 mm and i~ 5hown ~paced from ths 40ttom
squeeze roll~r llB ~y ~oUt 5 mm while ~lmo~t
touching the lower ~pp~ying roller 104. ~gain, the
pr~mary function of the support roller 1~4 is to
prevent ~mall ~eparated ~trand~ ~rom droppin~ out of
the web a~ it passe~ through the apparatus 100 bu~ it
has e ~econd~ry purpo~e wh1ch will b8 descri4ed
herein~fter.
~ 11 o~ the pairs of ~sller~ 102, 104, 110
and 118 and the support rollers 116 ~nd 124 are
supported fo~ rotation in an open en~ed baSh 1~6
ha~ng a bottom 128, sides 130 ~only one shown) and
at l~a~t a pa~tial down~ream end 132, The bath ~6
is inten~ed to contain the bonding agent, pre~erably
in a foam form, as will ~e describ~d in mo~e detail
hereina~ter~
A~ the down~ream ~nd, a Con~eyor b~lt 134
shown onl~ in part is supported or ~i~placement on
~paced rollers 13~ ~one only ~hown) to reeive the
co~te~ and ~pread web ~rom the bath 126 for onward
LH~ BULL I ~UN r'ltL8. 613 65~ 4906 P . l~l
8g61
16
pro~esslng for e~ample ~ ~escribed with re~erenS~e to
Fiquxe 1. Tha conv~yor 13~ is dispase~ within a
hougin~ 13~ bu~ ~his snd the conYs~or 134 Inay ~ak~
any s~it~ble form ~nd w~ll not ~e des~ribad Çur~h@r,
5 A third ~upport roller 1~0 i8 ~upport~d for rotat~or
about ~n a~l~ p~r~llel ~o the other descriibed ~o~
betw~en th~ lower ~gueeze rol ler dnd ~he ad~ 2c~nt
con~eyor rollex 1~5. The purpoge o~ the third
~upport roll~r 140 i al~o to prevent small sep~rated
10 str~nds from ~ropp~nq out o~ the coated and spread
web .
Ag noted already, the ba~h 1~6 is ~r~marily
int~nde~ to t~ke oam bonding agent ~ ich may be aB
previou~l3r desar~bed and this may b6s introduced to
15 the bath in ~ b~tch manner or ~ire~tly onto th~ ~e~
within the batl~ immediately ups~e~m o the apply~ing
roller~ 102 or el~ewhere up8tream of the sSluee~e .
roll~rs 118. The ~qu~e~e roller~ 118 ~queeæe ~sce~s
bon~ng agent out of ~he impre~neted web and it is
20 ound that the excess is ~rawn by the anti-clockwi~e
rotation o the upper rolle~s 102 and 1~4 over~ th~
top ther~f back to u~stream o the roller pair 102
where~ its re~urn passage is blocked ~y a parti~l wall
142 e~ten~lin~ acro~ the bath abovs the plane of the
25 nip~. A ~im~lar mo~ement of t~e e2~cess bol~ding agent
is caused between ~h~ bottom roller3 102 and lo~ and
the ba~e 1~8 of the bath 1~6 and the ~eturn pa~sa~e
of ~h~ portion of the e~cess bonding agent is
prevent~d l:-y a p~rtial wall :l44 e;4tending across the
30 width of th~ bath between ~he ba~e 12~ and the iræt
support roll~r 116. ~ well 146 in the ba~e 12~ o
the bath allow~ a ~reater volum~ of bonding ag~nt to
be ~ccommodated ben~ath the rolleræ 1~2 and 104.
It h~s ~een found that even be~ter
lY~ lY ~ vlt~ ~ ~,ULLI~iUN MtL~. 613 654 4g06 P.20
impr~3gnation o~ ~be web i~ c~u~d by th~ provi~ion of
a æhroud l~ hich extends across th~ width of the
bath f rom imme~ c~l3r adj acen~ the ir~t support
roller 11~, b~n~ath ~n~ p~rtly around t~e bo~ton~
5 ~pplyin~ roll~r 102 to l~etween the bo'ctom rollers 102
and 104, ben~atll an~ partly around the bottom ~oller
104 to ~djacent the second ~upport roller 124 and the
bottom s~uee~e roller 118~ The shroud 148 e~ en~ in
clo~e prosisnit~ to the lower arc~ o~ th~ bottom
rol~er~ 10~ an~ 104 but exc~ss bonding agent is
carried ~dtacent ~he ~hroud between the peak~ 32 o~
the bottom applying ~oll0rs. A 1~red lip 150
def ine~ a ~unn~l to rec~i~e ~xcèss ~ondin~ agent f rom
between the second support ~oller 12~ and the bo~tom
squceze roller 118.
rhe roller pAir~ 102 and 104 are ~hown
relati~fely clo~ely spac~d and ~n pr~ctice this
spacing msy be of the or~er o~ 25 mm. In a
mo~i~ic~'cion, th~ roller pairs 102 ~nd 104 may ~e
~o spac~d b~ a ~other greater di~tance such as the
spacing betwe~n ths drive ~ollers 110 and the
- applying roller~ 10~ snd a similar support roller m~y
be di&po~ed betw~en the bottom roller~ 102 an~ 104.
The ~escribed meth~d and apparatus have been
ad~anced merely by way of e~planation snd many
modi~icatio~s ~n~ vari~tions may be made thereto
withou~ departing rom the spirit and ~co~e of the
~nvention a~ defined ~y the ~PPended c~aims~
~0
.
