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Patent 2220935 Summary

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Claims and Abstract availability

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(12) Patent Application: (11) CA 2220935
(54) English Title: INTERNAL MIXERS
(54) French Title: MALAXEURS FERMES
Status: Deemed Abandoned and Beyond the Period of Reinstatement - Pending Response to Notice of Disregarded Communication
Bibliographic Data
(51) International Patent Classification (IPC):
  • B29B 7/12 (2006.01)
  • B29B 7/18 (2006.01)
  • B29B 7/20 (2006.01)
(72) Inventors :
  • BROWN, CHRISTOPHER JOHN (United Kingdom)
(73) Owners :
  • FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED
  • FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED
(71) Applicants :
  • FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED (United Kingdom)
  • FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED (United Kingdom)
(74) Agent: MARKS & CLERK
(74) Associate agent:
(45) Issued:
(86) PCT Filing Date: 1996-05-13
(87) Open to Public Inspection: 1996-11-14
Availability of licence: N/A
Dedicated to the Public: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): Yes
(86) PCT Filing Number: PCT/GB1996/001128
(87) International Publication Number: WO 1996035507
(85) National Entry: 1997-11-12

(30) Application Priority Data:
Application No. Country/Territory Date
9509742.4 (United Kingdom) 1995-05-13

Abstracts

English Abstract


An internal mixer comprising at least one rotor supported to rotate about a
predetermined axis within a mixing chamber, at least one projection mounted on
the or each rotor and extending towards an internal wall of the chamber, and
means for rotating the or each rotor about its axis, the said at least one
rotor defining projection edges of different geometries and being rotated such
that each of the said edges is a leading edge in at least part of a mixing
cycle, whereby material within the chamber is subjected to different mixing
actions by the edges of different geometries.


French Abstract

L'invention porte sur un malaxeur fermé comprenant au moins un rotor tournant autour d'un axe donné à l'intérieur d'une chambre de mélange, au moins une protubérance formée sur chacun des rotors et s'étendant en direction d'une paroi interne de la chambre et un moyen d'entraînement du ou des rotors autour de leur axe. Le ou les rotors définissant des bords saillants de géométrie différente et tournant de sorte que chacun desdits bords constitue un bord d'attaque pendant au moins une partie du cycle de malaxage alors que le matériau présent dans la chambre est soumis à différentes actions de malaxage par les bords de différentes géométries.

Claims

Note: Claims are shown in the official language in which they were submitted.


21
CLAIMS
1. A method of operating an internal mixer comprising at least one
rotor supported to rotate about a predetermined axis within a mixing
chamber, at least one projection mounted on the or each rotor and
extending towards an internal wall of the chamber, and means for
rotating the or each rotor about its axis, the said at least one rotor
defining projection edges of different geometries, wherein the said at least
one rotor is rotated in a first direction during part of a mixing cycle and
in an opposite second direction during a further part of the mixing cycle,
whereby material within the chamber is subjected to different mixing
actions by the edges of different geometries as a consequence of the
change of direction of rotation of the at least one rotor.
2. A method according to claim 1, wherein the or a first edge of the or
each projection which is the leading edge when the rotor is rotated in one
direction is relatively steep so as to grip material to be ingested and
thereby force material into the chamber, and wherein a second edge of the
or each projection which is the leading edge when the rotor is rotated in

22
the other direction is relatively less steep so as to encourage material to
flow over the radially outer surface of the projection.
3. A method, according to claim 2, wherein the first leading edge is
inclined at an angle of less than 45° to a radius drawn from the axis of
rotation.
4. A method according to claim 2 or 3, wherein the first leading edge
is undercut.
5. A method according to claim 2, 3 or 4, wherein the first leading
edge defines at least one sharp corner.
6. A method according to any one of claims 2 to 5, comprising two
rotors located with the nip between the rotors beneath a material inlet
and above a material outlet, the rotor supporting interlocking projections
shaped such that the leading edges of the projections when the rotors are
rotated to move the projections downwards at the nip grip material

23
introduced through the inlet, and such that the leading edges of the
projections when the rotors are rotated to move the projections upwards
at the nip force material within the chamber between the internal wall of
the chamber and the radially outer surface of the projection and/or
between the rotors.
7. An apparatus for performing the method as described in any
previous claim, characterised in that the driving means of the internal
mixer are reversible.
8. An internal mixer substantially as hereinbefore described with
reference to Figures 6, 7, 8, 9 or 10 of the accompanying drawings.
9. A method for operating an internal mixer substantially as
hereinbefore described with reference to Figures 6, 7, 8, 9 or 10 of the
accompanying drawings.

Description

Note: Descriptions are shown in the official language in which they were submitted.


,~A 0222093~ 1997 ~ 12~ t~r ~ ,7,
WO 96/3S507 ~ 96101l2
I~T~NAT. ~v~,~c~
The present invention relate-c to i~ternal mixers which are used for
mixin~ h~ of compoond incorporating ~i~ferent componentr which
mu~.t be mixed tog ~th~r to provide a h~ 1 mixture,.
Various d~c~ s o~ internal mixers ~.re currently in u~e in for
ex~mple the rubber ~n~ plas¢ic~ industrie~ to produce compound~ for a
wide rallge of product~ ~or e~cample tyres, electrical lnsulation plastics
-~d the li~e~ In such mixerr., cor~ o~ ~lt~ such as r~b~er, ~Illerr.,
reinforcing agent~ ql additiver snd curatives are inl~ .ced into a
m~xing ~hu~nl through an inlet r~ ~ le~ding to an G~e,.i,.~ in a
wa}l of tlle ç~ I-er. At le~st one rotor turns ~itbin the chamber, tlle
rotor ~upporting projections which ~xtcnd toward~ the internal wall of
the t'h~mb~,
The rotor hag to E.L.ru~... a number of functions. Fir~tly bulk
matel;~ls, for ~mrle large pieces OI rubber, must be dr~n i~tn the
chamber and divided into ~maller piece~ or ~t lea~.t r~-r~ared Seçondly,
the t~er~lure of the m~terial within the rhzvnbcr m~st be inc~ ~ s e ~ by
the QpFli~stlrl. of ~ e~ and ~trnin~. The te~nl,er~lurG il.C-e~ f i~
primarily a result of the stre~s ~pplied to the material through contact
with the internsll surface~ of the mixer, that is the ~urfaces of the ~h~rnher
wall~ and of the or each rotor. The major crlteria in applyin~ ~tre~g are
UB~I~E SHEET ~RULE 2~

12 NOV '97 08:47 . ~ ---CA 02220935 1997-11-12 P 7 ~~'-~
'. ~:.'.
~o 96n55~7 P~ CIO1128
firstly that the lln~t...;dl is in contact ~Yith r"~h;ne surf~ces ~nd secondly
that there is relstive moYement b~ the material and the surf~ces. vT~irdly, the sep~rate components of the mixture mu~t be dfslriLht~J
throughout the ~ e o~ the ch~mber in order to achieve a fine
lr;Lul;~._ of ~e vsrious ingredients. ~or ex~mple, filler ~g~l ~erates
~ust be d;~ , ' and l~roken do~ into a desired fine t~ ' rle ~ize and
then dist~ibuted through the bulk of the compoul~d in t~e mixer.
Fo~ rth~y~ the mL,;ed compound mu~t be plasticized in order to achieye the
r~ ;.iLe final r~eolog~r~ u~ s. ~inally, ~11 of the fully~ mixed
compound must be discharged from fhe Inixer thro~gh ~n ~lltlet whicb
can be opeoed 1~ the c~n-b~r walL
Given the dilie.~ unctions which the mu~er must perform
during a sihgle batch mixin~ operation, snd given tlae ~.h~ s in the
properffes of the mixed materi~l during the course of a batch mixing
ope}-ation, the design of inter~al mixers must be such th~t adequate
perforD:lance i~ ~chieved in all the phases o~ a mixing operation. As a
result it is alwayi n¢ccssary to compromise on certain features of the
de~ign of an irlternai mixer to ensure that the o~çr~ e.ro~mance is
acceptsble. By way o~ example, inter~al mixers with interlocking rotors
are widel~ used in the rubber industr~ such mixers, t~o rotors are
arlan~ed side by s~de within a ~ingle chamber with their axes of rotation
parallel. The rotors comprîse proiections or nog~ supported on gonerally

'P~;'~'''~'!~A ,.0 2r2 2~,0~9, 3 ~i. ~,_.1 ~,~ .
wo 96/35S07 ~ ~1128
~ylindrical shaft~, the radially outer end of the nog~ on one rotor
ex~ to a short distance from the ad~acent inner wall of the cavlty
and a short distance ~rom the surf~ce of the shaft of the other roto~. The
rut,~Liû., of the two ~otors i8 synchrohiged to en~ure that the~no~s on one
rotor do not cor~t~ct the nogs on the other. Wlth an ihterl-~ckln~ rotor
mlser of this type, a single batch miXinX operation ~nvolves three separste
phases. Firstly~ the rotors serve to ingest the ~ate~ i~ls into the ca~ity, to
distr~bute tbem around the ch~mber, and initially to ~ AtP the
~attr;~ls by mean~ of the ~ n~ ~ction taking place bLI.. ~ tbe
rotor~. Secon~ly, a8 the materi~l i8 heated and so~tens, it begins to flow
o~er ~e radially outer ed~es of the nogs, that i~ through the ~p ~etween
the nogs and the chamber ~valls. Becaus~ o~ the lenge~ and width of this
gap, the material is subjected to substantial ~ r ~ir.r,nl ~nd ghear slr~ in;
and stralin~, thereby achieving good di~L~ ~;vll~ while the disposiffon of
the nogs on the roton prov;des a degree of circulatory flow ~vithin the
rh~ l~er, thereby ~s;~ g with the distributive ~ inE, Thirdly, the
rotors ser~e to propel the cou~uu~d do~nward~ 3nd outwards throu~
the outlet ~hen a discharge door is opened at the end or the mixing cycle.
The ~,unf~ r~tion of the nog~ on the ro~ors of an internal m~xer
with interlocking rotors has been e~olved o~er many year~. A desi~h
which i~ Chr. e~ in genoral use Is de~cribed in E~rope~n Patent
Specification 0170 397. In that desl~n the rotors are ~epar-tLd by a gap
.SU3STITUIE SHEET (RULE 2B~

lZ NOV '97 0g:48 ...--- CA 02220935 1997-11-12 P.9
W 096/35507 r~ 5/01128
which is l~rge enough to e~ure that snffir;~nt space ~ available to ingest
the msterlal r~l.,Li~rel~ easily, but which is smsll erc!-~ to ensure that ..
adequate ~ ;L--Q1 and ~hear ~ 5 a~d strain rate can ~e spplied to
t~e material in order to obtain di~ Di~ c mi~cin~ of it~ cG~yu"c~1s~ The
larger tlle rotor ~ap, th~ greater the in~e~tion but the less the di~ a;vl~
Accordi~gly the n I t- of the rotor gap must be a compromise given the
competing requireq~ t~ It i5 also necP~Q~y to ta.ilor the ~1 o~l of
o~ ti~ll of the r~sr~ e, to the particular 6tage oî the mixing cycle, for
~mplr to reflect the physical and c~ç~ J~ ion of the ,.,~l~rl~l.
This can inYolve the varia~le~ of speed of rotation, the pressure with
which msterlsl to be i"~- ~tcd jB forced into the ~ er opening, tbe
temperature of the ~.~iA1urc and the time forwhich the mixture is wu~l~cd.
Of th~se ~rariables, tem~r~r~ control is generall~ the most significant.
It is therefore hecA-~Qry to desi~ internsl mixers in ~uch a way as. to
ensure that the required levels of ~yt~rclon~l and shear stres~es, strsins,
and t~ er~ture are achieved at all st~S~eY of the cycle whilst ~je-~ing
minim---n cycle times. Given the ch~ngi~g rheological ~.u~e.li~s of the
mi~ture during the cycle, thesç factor~ camlot be readll~ optimised d~ring
all parts o~ the cycle Thus the design of the know lnternal ml~ers
represents a set uf care~ully e~tab1;shed compr.:
Known internal mi:~ers are conventionaUy drnren in ~ single
direction during the normal mixing proces~. ln mixers with two contra-
~. ~'L ~
. . _

222~93s 1997
wo 96/35~07 E ~ 610l1
rotating rotors, the lç~ edgos of.the two rotors are geometrically
"h~ y i~P~ l l'hu~ each rotor subjects the material to be miXedto the same mixin~ action. It is belie~ed Shat in some Li~ ' it has
~een posF~lr to r.i-c~,e the di,~i-t; .. of rotor movement to 'ra~ ts~te the
release of j5~mTne~ roton but it is not believed that iDternal mixers haYe
e~er been or,~ tL~l in a nûrmal mixing cycle ~vhich indudè~ phases
during the yr~Ce51 0~ miXiDg a ~ingle b~tch during ~vhioh the ~ ecli~. of
rotaffon of the rotor~ is r~ ed.
lt is an object of the ~nJF ~ t i..~c~.ti~n to pro~ide ~n improYed
interual miger.
ACLU~a~ to t~e ~ t in~ t;u.., there is pro~idcd arl internal
mixer cou~r ;-~g at least one rotor supported to rotate about a
predet~....~cd axis within a mixing chamber, at least one projection
mounted on the or each rotor snd RY1Pn~ tow~rd~ an internal wall of
the chamber, ~nd means ~or rotating ~he or each rotor about jts axis, th~
~aid at le~ one rotor defining projection edges of dir~1_~.t geometries
and bei~g rota~ed ~uch that each of the said edge~ us a leadin~ edge is at
lea~t part o~ a mi~hg q~cle, whereby ,..~t..;al within the chaml~er is
s~bjected to different mixing actions ~y the edges of di~rL~ .t ~eometrie~.
In one embodiment of the pre~ent ~DVention, thc rotatlng mesns rotates
-., the or es~ch rotor in either dir~ ~-- about it~ axi~, and the o'r each
proJection i~ formed ~ueh that the ~hapes of its le~din~ and ~r~iling edge~
SU8S~I~U~E SHEFI (RULE 26) .

12 NOV '97 08:49 .. CA 02220935 1997~ 12 P. ll
~o 96n5507 r~ "01128
are ~ .,t, where4y the mixiog action to which material within the
rl~a~hf~ ig l~ubJected is a function of the direction of ~.Jt2.1iu.. of the rotor.
The inventlon al~o proYides a method hr operatin~ an iDte~nal
.ml~er comprising at least one rotor ~ ~~ 1 to rotate about a
predet~ axi~ withln a chamber, and at lenst one projection
mounted on the rotor and e!x¢rnrl;n~ IU~ D an internal ~ ll of the
rl~hçr~ the or each projection, be~ng formsd such that the ~hapes of it~ -
in~ and trailing ed~es are differ~nt, wherein a ~atch of m~terial is
deli~ l to the cavity, the or ~ch rotor ls rotated in a first direction to
~ubject the material to a fir~t mixin~ progrnmme in which the mixing
action i~ to it~ initial con~ inn, and the di~ lio,. of rotation
of the or each rotor is revex~ed at le~st once h ~ubjec~ the material to st
least one furt~er mixing programme in which the mixi.n~ sction i5
appropriate to tbe condition of the material affer completion of the ilrst
mixing pro~r~mme.
In ~n alternative elnbor~ ert of the pre~ent invention, in which at
least one rotor is proYided ~efin;nE~ at lea~t two proje~;l;u.,s, the or es.ch
rotor i~ rotated in only one direction duri~g a mixing cycle, the l~ in
edge of s~t least one projection i~ relntivel,Y steep so as to grip material to
be ingested ~nd iorce it into the ch~mber, and the leading edge of at lea~t
one other projection i8 relatiYely le~ ~teep so as to encourage li~at~ l to
now o~el the radially outer surface of the projection.

"~A,~ ~Or ,2~2,~2~0 9 3 5 ~ 9 9 7
WO 96135507 ~ 6/01128
The ~ t invention i~ ~ased upon the realisation that in sn
internsl mixer it i5 the leading ed~e of the pro3ection which largely
determine~ the ~ixi~g action to which material within the rh~n her is
s~bjected. Thus by arrangin~ for the rotor to be re~ersible ~nd r~
the ~lir~-lion Or rotation of the rotor during the mixing of a single batch,
u~d perform~nce can be ~ e~ by d. i~ln~ the k~ g edge of
the projections when the rotor turn~ in one direction to be Dppropriatei. for
the condition of m~erials at one ~tage of' the mixing cycle, and d~
the leading edge of the projections when the rotor turns in the o~pG~ite
directloD to be ~ pri,-tt for the condition of the material to be mixed
at another stago of the mixing cyde. Altern3tively, in a double rotor
r~ e in which the rotors turn in only one dil cc~;u~ du~ng a ~
mi~ing ~cle, one rotor can have a leading edge which ensures rapid
in~ of material at the l~e~ g of :~ ~nixjng cycl~ and t~é othe
rotor a leading ~dge appro~ ute to a latel~ stage in the Dame mixing cycle.
1D a mar~ine with reYersible rotor di.~ io~., the rotor directi-,A
may be r~ DcJ two or rnore times during a single batch cycle~ for
eYs~nrlc to assist in ma~erial ~ jL~ or ~o ensure ~ood
disl,.;.~ion/distril: ution of in~çredient~ added to the c.~ .d durin~ the
course of the mixing cyde. Thus the designer can produce an i.~l~.. I
~nixer With chal~cteristic~ that in the prior art would ha~ve re~uired two
sep~rate mixers used ~equentially to proce~s a single batch.
' SUBS~llUI~ SHE~ (Rl)LE 2Bj .

-
12 NO~ '97 08:50
CA 02220935 l997-ll-l2 P.13
W096~5507 ~ 96~1128
A first edge of the o~ each projection which i~ ehe ~- ~jn~ e~ge
when the rotor is rotated in one direction may be relati~ely steep so as to
grip ~-~t~ .l to be i~ d ~nd thereby ~orce mat~rial into ~he ch~n~_ ~
whereas a second edge of t}le or e~ch pro3ection w~icS is the l~,q~in~ edge
when the rotor is rotaffllg in the other dlr~,.liu~ i~ rolati~ y les9 steep ~o
as to encourage material to flow over the radially outer :-ur~ ~ of the
pro3ection, thereby providing for optimal ~xt~r~ion nO~v into the ~ap and
s~ear flow w~thin the gap. The first edge is thô !~ ng edge during ill~tl~
lo~ ge~inr and plasti~ ~ti~ and t~e second edge is &e l~r';"~
edge during a ~ubsequent stage in the mixing cycle It would of cour~e be
po~ible in a further stage of the mi~ing cycle to again reverse the
direction of rotatio~ of the rotor.
Thô fir~t leading ~dge may be inclined at an angle o~ les~ than-45~
to a rsdiu5 dr~n ~rom the axis of rotation. The small~l this angl~, the
~itC~.EiLr the surface o~ the proiection advan~in~ towards ~he material to be
m~xed. That steep edge may be provid~ with an undcrcut so as to
~o:~;L;~ grip introduced material and in addition could have sharp
co~ner880 as to a~sist in bre:lking up initially introduced ns~terials.
The or each projection ~n~y be proYidOd with in~lerit~tions and
d~ ~,,,sions thst sre sloped in the helical, axial or c;~ ~rcntial
cliG~ so as to impro~e material distribution. It ~vlll be ~ e~;..l~d
that in contrast to p~ior art mixcrs which during a mi~ing cyclO rotated in

lZ NO~ '97 09:06 CA 02220935 1997-11-12~ P-47 .~ .
,,' ,.' ~
only onc ~lir.,_liol~ it would 4~ pos~ible in ~ccordance with the p~escnt
invention to pro~ide projections ~IP~ ;ng sp~ce~ which are "de~d", th~t i~
to ~ay which are not ~wept out by tl-e flo~ of l,la~ vithin the mixelt
when the roto- tUrn5 in one direction, providi~g thos~e area~ a~e swept out
. . .
when the di~ectiop df rot~tion i~ ed.
The ~ in~ention i~ npplicable to a variet~ of intern~l mixer
;grc b~t is particul~rly applic~ble to mix~rs hAving fwo rotors locslted
with the nip between them beneatll ~ m~l~e~ial inlet a~d ~ove q mnterial
outlot, the rotor 5upporting interlocking projections sha~ed such that t~
e~rli"a edges of the proJections when th¢ rotors are rotnte~ to move the
.. . . . .
proje~-~ion~ down~ ds at the nip grip thntenal h~ luced thro~gh the
inlet, and such that tl~o leadin~ e~ges of the projections ~hen the rotors
are rotate~l to move the proje~tions up~Yards at ~he ni~ force mnteri~l
wit~i~ the chambe~ against the i~fernal wnll of the char~ber.
~ mbo~imehf~ of the present in~ention will now be descrihed, by
way o~ ox~mple, with reference to the accompanying dra~rin~s, in which;
Figure 1 ~ a Yiew from abo~e of t~o rotor~ of a con~ertion~l
internal ~i~er in ~vhich such rotors are arranged side b~ ~ide within a
mi~ing chamber;
Figure ~ 8ec~ iew Oh the line ~-2 of Figure l;
Figur~ 3 is a ~e on~l Yie~Y corre~pollding to that of Figure 2
-~howing the ingestion of material to be mixedt,

~ 12NOV '97 0EI:51 - ~ CA 02220935 l99i- ;; i2 ~~
WO 961~SS07 ~ 610~128
Figure 4 illustrates a later stage in t~le mixing process shown In
Figure 3;
Figure 5 ill~L~te3 the ~tructure of a~ alter~lative inter~lal mixer of
çonYpnti~r~ql form;
Figure 6 is a v~ew simil~r to that o~ Figure 2 but sho~ving
--~if; ~ s made to the .. . se -nn Or a rotor. in accordance with the
pre~ellt i--~_..t,o.-; and
~ igure 7 illu:~t~ at~ 5~ n the rotors of ~ rever~ible mixer
in whiçh each rotor ~as been ~nrlif~Ptl in the same mqnnPr a5 the rotor of
~igure ~i;
Figures 8 ~nd 9 ~ P~ti~Q~ly re~ ent rno~ifir~tion~ which ma~
be made to a rotor in accordance w~th the present invention; and
Fi5~ure 10 illu~.1r2.1.s in ..0~3 ~tion the rotors of a mu~er h ~hich
each rotor rotates in only ohe direction b~t the ~otors have ~een motlifi~l
in dif~erent ~ays such that the rotors ~ubject material ~vithin tbe mixer to
.lir~iut mixi~ ~rtlon~,
R~s~r~ , to Figures 1 and 2, the illustrated con~entional inter~al
nlixer is ~ ct~red by the applicsnt~ ~nd is sold as the ~'Intermix1'
interllal mixer. The il~ led mixer eon~ s ~ Lasin~ drfi~ n
internal w811 1 ~vithin which rotors Z snd 3 are ~upported. The rotor 2 i~
supported on a shaft 4 and in use is rotate~l in the direction of arrow ~
The rotor 3 i~ ~upported on ~haf~ ~ and In use is rotated in the dlr~_Gon of
S~D.~ ;7~

12 NOY '97 08:51
_ 02220935 l997 ~
WO gC13S507 r~ 96/0~128
11
srro~r 6, The r~tor 2 ha~ a cylindrlcal outer surface from whicl
r projection~ 7, 8 and 9 extend toward~ the wall 1. The rotor 3 sqpl G~l~
projections 10, 11 and 12 which also extend towards the wall 1. The
proje ~rll 7 and 10 deime portioIIs of a hclix and t~e ~otor~ are ar.s~
such th3t the p,rojection 7 is r~e.,;.ed in the spsrin~ bLI.~e- proj~ ".s
11 and 12 a~ the ~wo rotor~ are tu~ned and the projection 10 is r~c.~
l,eh. ~L~ the two proje~t~ 8 and 9 ~ the rotors turn. Thus the
proje t.r 1- of the h~o rotors are in~erlocked and such mi~er~ ~re
~enerally t.er..fe~ to q~ h~in~ interlockhg rotors. ~t the nip ~P~Pd
Leh..;~.~ the t~o rotor~ there is a small clearaDce ~pt~ the radiall~
outer snrface of tbe ~ojc.t;~Ys on one rotor ar~d tbe adjslcent cylindr~cal
SL~r~w of the other rotor.
The projection 10 defines a leading edgç 13 ~hich subtend~ ~n
an~le 14 of about 53~ with a r~diu~ dr~wn from the axu of rut~tiul. of the
rotor. That sam¢ pro3ection defines ~ tr~ilin~ edge 15 ~hich defines a~
~ngle 16 rel&t;Yc to a radius. The angles 1~ and 1~ are ~ s~ tl~,lly the
same. Similarb, t~e projection 11 define~ a leading ed~e 17 ~èfi~in~ an
angle 18 of about 47D~ and a tr~iling edge 19 defining sh angle 20 ~vhich i~
~nh5tu~tisllly the same as the angle 18. Thus the shape of the 1 - ~ing edge
of each proJection ic substantially the same ~s the shape of the trailin~
ed~e of each pro3ection. ~he ~hape i~ not alway~ identical ~nd in some
form~ o~ the h.t~...dA internal mi~er manu~actur~d by the applicants
SUBSrITUl~ S~IEET IRULE 26) - . -
-

lZ NO~ '97 ~9:06 CA 02220935 1997-11-12 '~ - -~ 4
thç~-e are minor JifL,~ ce3 I~.,h. c~ tlle ~h3pe3 of the l~ n~ and tr~iling
edges a6 c~ be ~pp~e.i3ted from the tisclosure of.l~uropes~n Patent
S~ O 170 397. Thes¢ di~erencu between the shape of the
l;n~ and tl~ailing edge are rdath~ely minor ho. .,.el and ~re generally
co~ce~ed with.:~~ooth~g he nOw of mate~i31 over the project~ons in.
~egions ad~acent the ~s of the rotors. ' -~ ~
The casing ineor~or~t~s an inlet Zl in which a ~ Z2 is ~lidably
recyi~ eL The casing also COlTlpriseS an o~tlet beneath the nip between the
rotors. Thc.outlet is not shown in Figures 1 snd ~ but it will be
ap~ tcd that ff cu~~ 3 a doo1r which i~ llorm~lly fixed in position
~nd ~hich c~n be opened to dlsch~rge a batch of miYed material from the
chs n~l e~ ~ - ,
~ igure 3 i}lu~lr~tLs ~e oper~tio~ of the mi~ture of F~gur~s I and 2
when ~ batch of raw polymer is ingested. The polymer is ~enerally
~upplied in r~ el~ large pieces nnd must be broken down withi~ the
mixer. The ~troduced mate~i~l may be ~ s~e.l dow~ by the ra~n into the
nip of the rotor~ and the m~terial is gradu~ drawn into the m~ g
ch~mber through the narrow gap betwecn the rotors. The ~ap be~veen
the rotors ~nd the degree to which the m~teri~l to be l~ d is gripped
by the roton ~i~nil~ .tl~, affect the r~te ~t whic~ material can be
ingested~

CA 0 2 2 2 0 9 3 5 1 9 9 7 ~
W0 96/35507 ~ r _ '01 128
Re~erring ta Figure ~, thi~ lllùsl~ the disl,o.,i1iu,. of the mate~ial
being m~ed ~hortly beiore the end of the }~ ng of a bat~h of'
materiaL It will be se~n th~t ram has been l.,..~r.d considerably a~
compared with Fig. 3 and material no~Y~passes over the radially Outer
surface~ of the projectj~C The mate~ial is al80 worked bet~ A. the
rotors. The ~heolûgical c~nrlit;orlC ~Ithin the ~h~ber aré clearl~ ~very
dirf~ t at the l.~ of a ~atch l,.uces~i..g as illustrated in Figure 3
and at the end of the same batch as illu~t~LI in Figure 4. At the
be~;nr~ing of the proçess, it would be sdv~Dhg_ûLi. to widen the gap
L~ n the rotor~ so as to speed up ingestion and increase the us~ble
volume of the mlxer. The ~ap cannot be too lar~e however if the
compo~lents of the material to be m~ed ~re to be adeyullt~l~ sl~ ~; ~r 1 ~nd
distributed. At tbe end of the procesY, when the material to be m~bced is
warm and r~ 80~ it iS desirable for the m~terial to be forcèd
I.el..e~ the radia}ly ollter sur&ces of the projectlo~s snd the chamber
wal~ ~o as to en~ure adequ~te P~ ~n~jnnal shear 4tr~,~3~.~ snd strain r~tes to
obtah~ di;.~er.i~ ml~in~ of the componenb. T~e pres~ure u~Js1r~am o~
the proj~ n~ i5 p~rtly a filnctinn of the st~l,.,c,.;. of the I -rl;n~ edge ~f
the proiectjonc- As the material ~oftens, it i~ desirable that the proportion
of the material which i5 circulated between the helical projections rather
than forced o-ver the radi311~ outer surface o~ tho~e projection~ tend~ to
de~r~c, slld hence in later stages of the mixing process it would be

~ 12 NOV '97 08:5~ - ~CA 02220935 l997-ll-l2 .,, . P.l~
,
W O 96135507 r~ll~b96lotl28
desirable to mal~e the IPa~l;ng edges of the projc_ti~ less stBep so ~g to
encoura~e more materl~1 to pa66 o~er the radially outer ellges oF the -'
projections ~ r~ L. z~t;~g Cigr~ ht ç,y~n~ E5 and shear
Stl'~,3~ of thé mater~al. The 'r~ , rheolo~ic~ ~,rur_.1' o~ the
mahrial to l~e 'mi~ed hence ~orce~ the mixer de~l~ier to adopt a ~r~ole
series oi' c~ e~ when it comes to the cnr~ ;3Li~.- oi the rotors.
The l~n~j~ g edgeg of the projections are not ~s ~teep a~ would be ideal for
the ihitial pha~es of a Inixiug process for in~;....tiu~ and d~s~ JuLlon but
are ~teeper t,han ~ould be desirsble for the flnal sta~es of that process for
dis~ei D;G~.
The problems of ~ef~;lerl ro~or designs as~oc~tP~ ~ith ~rt-rlocl~
rotor mi~ers oT the type illustrated in Figure~ 1 to 4 ire encG~ d in
other mixer~, for e~ample the Banbu~y-type mixer sel~m~tica~ly
illustrated in Figure 5 ~n that ~ er a rotor 23 turIIs about axi5 24 within
A chamber 25. Material 2~ to l~e mLl~ed is tr~pped l..~,.e.n thè cha~ber
wall and tbe rotor and as a l~esult the material is smesred a~ainst the
chamber ~all. Give~l that the rheological pr~.~t. 1;.6 of the material to be
mixed ~ary o~er time due to hea~in5~ and pl~ tion the profile of the
rotor i~ once a~ain a compromise, the sln~lc b?tn~L~.. the rotnr surface
a~jaçent the ch~ er ~vall ~n~ the wall itself being :..~rr..,.~tl~ large to
en~ure that a fresh batch o~ material can be in ~Yte~ but 5nff~ tly~sma
to ensure that the softened material i~ a~eq~ately stressed. Once again, in
,................................................... . , :
. . ,, ~ .. .. .

~A 02,2,;2,~0.~935 199 "~
WO9~ .7 }~ .......................................................... ,,f~01128
internal mL~:ers of the ~ype s~h~ ffr~lly illu~trated in Figure 5 the rotor
. is turned in one dirL.hon only and there io no slgnific~nt dirr.... ~L~e
L_l. ._~ the ~o~ 6 r~liu-- o~ the rotor ~urface a~ l.h.e>,". the ~ m
~nd downstream s1des of tha~ ~urf~ce.
It ha~ .~een know~ to pro~lde an inter~lal mi~er Or the type
il~u;~lr~ted in Figure~ 1 to 4 with a r~ . 5iLle motor to enable the roton to
be dri:ven in reYer~e to assi~t in r~l~oci~ mmed mixer. No propo~al~
haYe been m~de hc.~..,.~Y ~o drire the rotor~ of an internal mixer in both
Ji~.i~t;o~s during ~ no-mal mu~in~ ~ru~ gcle.
The present Is~v~ntion relie~ upo~ a re~ Hon that a rQtor. can be
~ri~d to p~o~ide a first ~et of cor~lit;nn~ ~ithin a mixin~ c~a~nher
when rotated in one dir~. lic~ ~nd ~ Isecond set of c~ndjtio~ when dri~eD
In the o~Gg;l~: di. ~- tion. By sh~ping the ci~ fL. ~ ially spaced ~ides of
the pro~c_~iul~s in an approprS~te m~nnPr~ ~ rotor c~n be de~igned whlch
p~o~ide~ br~ance equivalent to t~at ~hich would be achieved by
using separate fir~t and second mi~erg sequentia~ly, the first mi~er in the
sequence bein~ rl to optimi~e ~c~fu~ al~ce in ~ first phase of a
b~tch miYlng pr.,c~s and the ~ecorld ~xer being dL.~ d to optimi~e
performan~ ~or the completion of that process. All th8t is ~ u;r~.l to
pUt the ;U~GUt;On into practice is a rededgn of the c;ren..lferentially
paced ~urfaces of the projections snd the ~ru~tls.on of 8 drive rnecl~
SllBSr~TlJTE S~lEFr ~RULE 261.. . .

....... ---12 NOV '97 08:5~1 CA 02220935 1997~ r.2l' .
~;5ro 96/3ss07 r~,~B~510
16
which i~ capable of driYing the rotors In both di.~,_hu~s over ~ -t
r~ u of a mLxing cycle. n
Figure 6 illustrates a rotor modlfied in acco~dance ~ith the ~ nt
inventio~, and Figure 7 illu~ lLs in c~c4s ~e~ion the ~o rotor~ of the
~ machine in whi'ch each rotor h~ the same co~ ;unq~ s that of Flgu~e
6. The general structure of the rotor of Fi~ure 6 l~ identical to ,that of the ',
rotor to the left hand ~ide of ~Igures 2 to 4 but It ~iU be 6een th~t the
upstream edge~ of the ~rojection~ ~Yhen the rotor turns in the dir~_lic.l of
3rro~ 17 h~ve been made morc steep ~here~s tbe u~lr~..m edg~s of the
~ro~e-t~r~ ~Yhen the rotor i~ rotating in the direction of arrow 28 hay~e
l;leen m~de les~ steep. The sh~pe of the surface~ be~ore mo~ ir-l; n in
accor~ance with the present invention i~ fed in Figure ~ by the
doffed ~Ines 29. ~iven the modifirQffoD of the rotor as shown in F~gure 6
and equivalent modifi~ations to the right hand rotor ~s ~ho~vn in Figure~
2 to 4, to produce the ~r.2~ e-..ent shown in E~igu~e 7, and a~uming
r~ of the dirc~lio~ of rotation of the rotor~ appropriate time~,
Yariou~ berefi~ arise. Firstly, by incre~sing the ~teepn~s~ of the le9~A;n~
edges of the projections ~lvhen turning in the direction of arrow 27 the
m~teri~l within the mixer can be more positively gripped by the rotors to
impro~e i~ i, transport of material within the ch~ber, and
~e of mate~ial from the r~her. In particular, the ~peed of , ,.-
in r~ , ls in.~ as- ' and the gap between the rotors ma~ be in-;t~ to

~ ~ 0222093~ l997-1~
WO scr~L / '
17 -
furthcr ih.l,r.,ve the speed of ~ ,il fi~ ~nd di~cbarge snd to increase the
us3ble vt/~ u a of tbe mi~or. .Sec~n~lly, by de.,..,a~:..F. the steepne~ of the
IrA~ ed~ses of the projections when turning in the Jir ,~ho-. of arrow 28
uan¢ltles of ~ t~;~;al are subjected to high stre~ ~nd strsin.
Figure ~ illu~lr~t~;. one simple modlfic~tion to a proiection whSch
c~n be made~in ac~ lance with the ~r~ t i~ .tlc~. To ~impli~ the
tio~, ~Igure 8 shows the pro~ection~ having ~traightened out the
curvature due to the grlindrical o~br surface of the ~nain rotor body.
The full line In ~igure 8 repre~ents th~ co~L~r .t; of the pro~ect~on of a
~on,~t~.LiG~al m~in~ machine of the type sho~n in Figures 2 to 4, whereas
the doffed line sho~s the c~ nf:g~rytion of a h~o~ifi~ projection in
accordsnce with the ~ l inYention. The arrow 30 represents the
direction of movement of the prnjection during the initial pha~e~ of the
mlxing ~ro in which the ~eIatively steep leading edge enables $he
l~tr~Jd~ced material to be po.,;ti..l~ gripped and forced into the ch~mher
interior. The arrow 31 re~r. ~nts the directIon of movement of thc
projectioh after reversal of the mixer dr~ve such t1tat the relatively gently
slop~ng l~e~ ed~e of the projection encourage~ tb~LI to tra-~el up
~h3t l~ in~ edge and over the upper portion of the projection during
which time it is subjected to high stre~s.
Fig~e 9 illu~tra~es yet another conceivable configuration ~or a
modified projection for I~Se ih ~n embodiment of the pre~ent in~ention.

lZ NOV '97 08:54~ ' CA 02220935 1997-11-12 r.2~
.
W 096/3550~ 96/OI12
Again the dotted line represent~ the ~O~ ;ur~tiOn of the mo~ified
projection, whereas the ~u11 line shows fhe ~t~ rd cGur~ r~tion~ It ~Yill
be seen that the leading edge (in the direcliu~ of arrow 30) i~ undercut so
~g to prû~r~de a vely secure ~'~,ripp;~g" of material durin~ the ing~ n~
phsse. A ~in &e IP~ g cdge t~n the di. ~,I;on of arrow 31) i~ ~ relati~ely
gerltle ~lope ~o as to plovide ~ l nO~ ~vithin the co~lv~ and
dl~erging gap~ and to ~ ul~r~g~ material to flow onto the radially outer
surfacc of thc pruJection. It m~ bc thae the undercut ~ul.r~;.Jr~tion as
~hown in Figure 9 would res~ lt in "dead" or ~t~gr ~nt sp~ce which ~ould
-not be adequately swept out if the rotor alway~ turned in the directlon of
arrow 31. ~his lleed not be a problcm ho.~ r providing during the final
~tage~ of a mL~ing cycle the rotor turn~ in a direction which ~voids any
dead ~paces o...~r.;r~ or eYample, during fhe initi~l in~e~tion pha~e
the projection could move in t~e direction of àrrow 3n, the rotor direetion
could then be reversed until imm~ tely before the completion of the
mixing cycle, ~nd tne di~ch~rge portion of the cycle could be L~f~ct~d after
a Ç~ er reversal of the direction of r~tz.tio~ of the rotors ~uch that
during the dischar~e phaYe the projection move~ ~n the dlrcctiu~ of arrow
3D.
It wil1 be appreciated ~hat in addihor to the control of the
dir~_llO~ of rotatiûn of the rotor~, a mixing cyc}e Cah 9180 be controlled by
adjusting the speed of rotatlon, the ~m pressu~e, coolant tem~_.alurb

wos6nsso7.. . ~ 1128
l9
and miYing ~cle dLr~liGL. The em~o~ Pnt of the pre~ent i~e~,l;on
described in Fi~ 6 to 9, in proposing the revers~l of the directiûn of
rotqtion of the rotor~ in as ~ :- t;on wlt}l a ~o~fi~tir~n to the shapc of the
rotor projectlons, add~ a furtber ~ari~ble which can be used to control tbe
mi~ing cycle, l The rotor~ c~n be dPal~rPd to optimlse inge~tion,
di~tribution 3nd di~charge o~,e~lion~ while the rotors o~c.~L~: in one
dir~ iu~ o.. ~.~. ..r.ls at t~e nip) ~nd to optimi~e dispersion and
pl~-~ir~tin~ while the rotors turn in the ~~k~ ~P ~lir.cti~ (upwards at the
hip).
The r.,l~ steep ed~e~ o~ the projections m3y be given su~face
fe..tur~s to i~,~u. e the gripping of ~aterial during the ingestion ph~se.
As il1..~.l~tt,.1 In Figllre 9 ~~nt~ ;ut~ may be fo~med hut al~ u~ti..a are
~r a~ihl~ or example the ~vviblon of relatively ~harp corners on the
projection edge~. Ih ad~ , the ~.~rr~cc3 of the projectiorls and of the
rotor L~ n the prù~ection~ may be provided with indenhtioD~ ~nd
depr. :- ~ that sre sloped in the helical, axial or circumferential
diree~in~ Experlmc.~l~t; will be nece~sary to define the op~i4~u
c~r ~ r~
In a double rotor mixer with contrs-rotating rotors, during the
i~ 1.û~ phase hi~gh pre~sure develops above the nip between fhe rotor~
and be~ the ram. When the rotor~ are r~ d, high pr~ ur~
develops benesth t~e nip in the re~ion of the chalnbe~ dischsrge door.
.
- 's~lJBSrl,TU~E S~E~ ~RUIE 2B~

..---. ---'lZ NOV '97 08:~5 CA 02220935 1997 il 1~.. . . P.25,~
~
WO 9G/355n7 P~ ;b~-loll28
The ~ char~e door i~ flxed in 1 o- if;~ nd t~us ser~ea ~ a high ~r~_lJr~
ram to ensure that the m~terlal to be mix~d is suhjccted to high stress. - '
The çol~cept of rotor direction reversal with rno~ of the
pr~3ectloh ~utr~ee~ provides an extra control variable wh~ch can be u~ed
for e~r~rnrle to achieYe shorto~- cycle time~ and/or greater mi~in~ capacity
a result of the clo~er match L_h.~l. the h~s~rhinc çonfigurat~on ~od
6~ .JC~ need~.
An alternative embo~imP~t o~ the invention ~s illwtrated in Figure
10. This embodiment compri~es contra-rOtating rotors 32 and 33 but the
rotor~ turn in only one dirci~liOI~ ~s in~l;rqte~l by arrow~ 34, The leadi~g
edges 35 and 36 of t~e projection on rotor 32 h~Yc been m3de r~l..ti~el;~
more ~teep by cl~n~in~ their shape from that intl~rptpd by dotted line~
The tra~lhg edge~ 37 ~nd 3E~ are of conventional shape, corre~por~;ng to
the shapes ~hown in Figures 3 and 4, in contrast, the leadin~ edges 39,-40
of the proiPeti~n~ on rotor 33 havc been made relatively le~s steep by
~h~ngjng their ~hape frorn that in~ir~tP~I by dott~d lines. The trsiling
edges ~1 and 42 are of conventjor~l ~hape.
In the embodiment o~Fig~re 10, the relaei~el~ steep lead~ng ed~s
3~i, 36 of the projectiono on rotor 3a en~ure rapid in~estion of material
into the mixer. The leadin~ edges 3g~ 40 oE the projections on totor 33
then ensure that the material is sobjected to high stregs and sbra~n.
~ ~ . ~ . .
, .

Representative Drawing
A single figure which represents the drawing illustrating the invention.
Administrative Status

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Event History

Description Date
Inactive: IPC expired 2022-01-01
Inactive: IPC expired 2022-01-01
Inactive: IPC from MCD 2006-03-12
Inactive: IPC from MCD 2006-03-12
Time Limit for Reversal Expired 2001-05-14
Application Not Reinstated by Deadline 2001-05-14
Letter Sent 2000-05-17
Deemed Abandoned - Failure to Respond to Maintenance Fee Notice 2000-05-15
Reinstatement Requirements Deemed Compliant for All Abandonment Reasons 2000-05-05
Deemed Abandoned - Failure to Respond to Maintenance Fee Notice 1999-05-13
Inactive: IPC assigned 1998-08-24
Inactive: Single transfer 1998-04-22
Classification Modified 1998-02-20
Inactive: IPC assigned 1998-02-20
Inactive: First IPC assigned 1998-02-20
Inactive: IPC assigned 1998-02-20
Inactive: Courtesy letter - Evidence 1998-02-10
Inactive: Notice - National entry - No RFE 1998-02-04
Application Received - PCT 1998-02-03
Application Published (Open to Public Inspection) 1996-11-14

Abandonment History

Abandonment Date Reason Reinstatement Date
2000-05-15
1999-05-13

Maintenance Fee

The last payment was received on 2000-05-05

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  • the late payment fee; or
  • additional fee to reverse deemed expiry.

Please refer to the CIPO Patent Fees web page to see all current fee amounts.

Fee History

Fee Type Anniversary Year Due Date Paid Date
Basic national fee - standard 1997-11-12
Registration of a document 1998-04-22
MF (application, 2nd anniv.) - standard 02 1998-05-13 1998-05-07
MF (application, 3rd anniv.) - standard 03 1999-05-13 2000-05-05
Reinstatement 2000-05-05
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED
FRANCIS SHAW & COMPANY (MANCHESTER) LIMITED
Past Owners on Record
CHRISTOPHER JOHN BROWN
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Description 1997-11-12 20 978
Claims 1997-11-12 3 143
Drawings 1997-11-12 6 288
Representative drawing 1998-02-24 1 11
Abstract 1997-11-12 1 17
Cover Page 1998-02-24 1 46
Reminder of maintenance fee due 1998-02-04 1 111
Notice of National Entry 1998-02-04 1 193
Courtesy - Certificate of registration (related document(s)) 1998-07-31 1 140
Courtesy - Abandonment Letter (Maintenance Fee) 1999-06-10 1 186
Notice of Reinstatement 2000-05-17 1 171
Courtesy - Abandonment Letter (Maintenance Fee) 2000-06-12 1 184
PCT 1997-11-12 55 1,621
Fees 2000-05-05 2 62