Note: Descriptions are shown in the official language in which they were submitted.
a~90~
~E~HOD AND ~PPARA~US FOR T~E TREA~E~T
0~ A CE~LULOSE-CO~AI~ING MA~ERI~
~ he present inve~tion r~latas in ge~eral to the produc-
tion of *ibrous intermediate products for the manufaature of
paper a~d car~board, or produots of chemical pulp processing.
Mor0 sp0cifically, it relates to methods and appara-tus for
the treatment of a cellulo~e-containi~g material.
~ he present inve~tion can be utilized to the utmo~t
advantage i~ the pulp and paper industry~
~ he propo~ed method and apparatus can be utilized fox
accompli~hiDg a number of important productio~ operation~ i~
the manufacture of pulp a~d paper~ this being do~e by far
more e~ficiently than with the know~ methods and apparatu~O
Such operation~ invol~e th~ impr~gnation of commi~uted ~ege-
table raw material, such as wood chips, with a solution of
cooking reagents, tha cooking o~ impregnated stock in the
productio~ of pulp, the ~eparation of chemically o~ thermo-
.:. chemically treated vegetable raw material into ~iber bund-
les or individual ~ibers and th~ g~i~ding o~ ~iber in the
manufacture o~ paper and cardboard.
~ urthermore, the proposed method and apparatus ~re suit-
able fox application L~ other industrles proces ing Yegetab-
le raw materials, for example, i~ the hydrolysi~ industry
for achiavi~g the improved impregnatio~ o~ a mat~rial with a
solution o~ acid prior to its hydrolysis.
Known i~ the prior art are ~umero~s methods for the
treatment o~ cellulose-c~tai~ing mat~rials, i~volving a
3~
:
- ~ 158~
~ 2 --
mecha~ical impact on the material i~ the process o* treat-
ment. ~his mechanical impact o~ -the cellulose-containing
material treated is effected wi-th a view to i~t~n~ify the
impregnation o~` the oomminubed ve~etabl~ raw ma-terial wi~h
a solution o~ cooki~g rea6snts or for the gri~din~ o~ fibro-
us materials in th~ production o~ paper and ca~dboard there-
from.
For example, known is a m~thod of treatment (see ~RG
Patent ~o. 2,818~320, U.S. Pa-tent No~ 3575791, UOS~S~
ventor's Certificate ~o, 506671) rasidi~g in the si~gle-
-step compactio~ of wood chip~ with the subseque~t submer-
sio~ thereof i~to a s~lution of reage~ts. ~or the implemen-
tatlon o~ this method us~ is made o~ a conical screw extrud-
ar by means o~ which th~ chips are compacted and o~truded
into ~essels containi~g the solution of reage~ts. ~he above
method of treatment and the apparatus, emplo~ed pximarily
~or the impreg~ation of wood chips with th~ solutio~ o~
cooking reagents, ~xhibit-the ~ollow~g disadvantagesr
. The singl~ step compressio~o~ the chips i~ ths sore~
extruder ~orces to arrange seq~e~tially a ~ew ~crew e~brud-
ers Sfrom three to:$ive) so as to ob~ai~ ~he uni~ormi~y o~impregnation, which makes the meth~d u~necessari~y ~omplex
and cos~ly and call~ for co~siderabla operati~g area~.
~ e number o~ chips compression cycles lLmite~ by t~e
~umber of screw e~truders ¢ompel~ to inc-xease ex~essivel~
th-e force of compression, which results i~ tha sig~ificant
deformatio~ and destructio~ o~ the c~ip~ a~ well as in the
d.amage o~ the pulp fibers.
,, Xl~
~ 3 --
The cansiderable compression ~orces applied~ the rigid
coupling betw~en the housin~ a~d th~ screw, and -the repeated
effectuation of compaction laad to the substantial expendi-
ture of electric powar~
Unoriant~d position o* ths chips in the screw extruder
in relation -to the compressing sur~ces also results in the
damage of the pulp ~ibers and i~ the impaired quality of a
finished product.
So~.o~the ~or~going disadvantage~ o~ the ab~ve method
and apparatus ha~e be~n obviated in a method and apparatus
for the treatment of a cellulose-¢ontaining material disclos-
ea i~ ~ranch Pat~nt No. 2,276,420. ~his method en~isages tha
single-~tep passage of chips together with a solution of
reagents between two pre~ i~g rollers rota~ing in opposite
directions at egual speed~. As compaxed to the above-consid-
ered mathod~ this method a~d apparatus ensure an oriented
po~ition of the chips in the process o~ treatme~t~ due to
which the chips are subjected to the compression b~ the ~ol-
lers in the optimum direGtion acros~ the ~ibers.
However~ in conseç~uence o~` th2 single-step compactiQn
o~ the chips, the ~orce o~ compression betw~en ~he rollers
for the unifo~mity of impregnatio~ should be so great that
the chips are i~evitabl~ c~ushed, which res~lt~ i~ the se
vere damage of the pulp- ~iber~ a~d, th~refor~, the paper
a~d cardboard produGed therefrom exhibit a l~w degree o~
mechanical ~tre~th.
~ he disadva~tages i~here~t in ~he abo~e-considered me-
thods and apparatus for the treatmQ~t o~ cellulose contain-
~ ~58~
ing materials have been ellminated to a con~iderable exten~in a methcd a~d apparatus ~or the treatment of fibrous ma-
terials discloæed in U.S.S.R~ InYentor's Certificate
~o. ~12808, which is used mai~ly for the impregnation or
grindi~g of ~ibrous wood materials. This method, identified
as prototypal, features the repeated mechanical compaction
of the material, such as wood ¢hips, supplied into the ap-
paratu~ togeth~r with a solutio~ of reagents. ~he method is
carried out in the apparatus compri~i~g a housing, a rotor
arra~ged insid~ the housing, a means ~or chargi~ the mate-
rîal treate-d a~d the solubio~ o~ reags~ts into a worki~g
chamber9 a drive shaft ana its driving gear. ~he dri~e sha~t
is ri~idly coupled to the rotor, while the rotor supports
compressing rollers mou~ted in carriers in a ~`ew rows. ~he
l~teral sur~ace o~ compr~ssing rollers aLd the i~ner sur~a-
ce of the housi~g serve ~or the repeated mechanical co~pac-
tion o~ the material treated.
Although such a treatme~t method is v~ry clo~e to the
optimum o~e, yet the method it el~ and the app OE atus for the
imple~entation ~hexeof have been found to di~pla~ a number
o~ disadvanta~es impairi~g the efficie~cy o~ treatme~t as
well as the quality o~ ~the product obtained.
Go~sidering that the diameter o~ the rolleræ is smallor
by a~ order of magnitude than the i~er diameter of the hous-
ing, the compxession of the material~ ~uch as wood chips,
takes place ununiformly over ~heir e~tire area~ particularly
at ths starting mome~t of co~act between the chips and ~ha
roller. Moreovsr, i~ o~e admits that the roller rollæ o~er
5~5
-- 5 --
the housing and the chips without slipping~ then it should
rotate around its axis with an an~ular speed which is al~o
~reater by an order of magnitude than the rotational speed
of the rotor and it~ value ~hould reach about ten thou~and
revolution~ p~r minute, thi~ bein~ un~easible for the desc-
ribed apparatus. Hence~ the roller will be unavoidably ~iv-
e~ to slippi~ with respect to the s~r~ace o~ th~ housing
a~d o~ the ~hips, thus resulting i~ -their abrasion. A cer-
tain amount of the chips treated findi~g their way into the
free space betw~en the adjacen-t roller~ is forc~d i~to rota-
tion by the rotor and upon i~teractio~ with the chips rema-
ini~g motionl0~s with respect to the housing undergoes ab-
rasion and destxuction. Additional destruction of the chips
is caused by the action o~ the carriers coupling the roll-
ers to the rotor.
~ hus, the above m~thod a~d apparatus ~or the treatme~t
o~ cellulose-containing materials su~er ~rom the following
disadvantages:
- the u~uni~oxmity o~ distribution o~ the compressin~-
~orce over the antire area of the wood ~chips leadi~g to
the ob~6ctio~able eo~ce~tratio~ of force at the poi~ts o~
eo~tact bstwee~ the c~ip~ and the roll~r and to the destruc-
tion o~ tha pulp fibers;
- the slipping of th~ rollers o~ the sux~ace o~ the
chip~ leadi~g to ~heir abrasio~;
- the de~tructio~ and abrasion o~ the chips pe~etrat
ing into tho ~pace betwee~ the ad3acent rollers a~d forced
i~o rotatio~ by -the rotor upon th~ir i~taractio~ with ~ha
~otionless chip3:
~ 1~8~
-- 6 --
- the destruction o~ the chips by the ¢arriers coupling
~he rollers to the rotor.
~ 11 this, as veri~ied by ts~ting, lead~ to that ths
mechani¢al treatment o~ the cellulose-co~t~ining material
i~ accompanied by the destru¢tion o~ a~ average o~ 27% of
the material treated.
Furthermore, it ~hould be noted that the apparatus in-
tended for tha împlementatio~ of the method de~cribed ~erein-
above has a~ inade~uate output. ~his stems from the ~act
that the total sur~ace o~ the compre~sing rollers participat-
i~ in the mechani¢al compactio~ o~ the material treated i3
considerably smaller than the i~ner surface of the housing
of the apparatust which also cooperates in the m~chanical
compaction o~ the materialc
It i~ an obaect of the prese~t inventio~ to improve the
quality of tho cellulose-co~taining material obtai~ed after
the treatment.
A further obje~t o~ the present invention is to step
up tha output of the appa~atus for the treatm~nt e~ a cellu- -
lo~e-contai~i~g material.
With these a~d other objects in view there is provided
a ~ethod for the treatment o~ a cellule~e-centaining mater-
ial~ ¢omprisl~g the stepæ of oontinuou~ly char~ing the s~me
together wit~ a solutio~ o~ ~aage~tæ i~o ~ workL~g chamber
a~d repeatedly ~echanically compaGti~g it by mea~s o~ the
cooperation b~tween a~ in~er a~d a~ outer workin8 bodi~s
1~89
-- 7 --
caused. to move in relation to each o-ther~ the outer working
body enclo~ing the inner working body and defining in combi-
nation therewith the a~oresaid working chamber, wherein,
according to the invention, t~le repeated mechanical compac-
-tion o~ the material is e~`fected by imparting wobbling mo-
tion to one ol` the wo.rking bodies and by rolJ.ing it over the
o-ther working body through a layer o~ the material treated~
said wobbling mo-tion and rolling being caused by the rotation
o~ a ma>ss being unbalanced with respect -to -the axi~ o~ rotation
and rota~a~ly coupled to one of -the working bodies.
Due to such a design during the wobbling and rolling
of' one o~` the working bodies over the other the material
treated is subjected to the repeated coll~pac-tion across the
f'ibers in the solution o~ reagents wi-thout the occurrence o~
mechanical impacts causing its abrasion or cuttingO ~his
improves -the q~ality of the cellulose-containing material
obtained a~ter the treatmen-t.
With these and other objects in view,-there is al~o provi-
ded an apparatus ~or the implernenta-tion of -the above method
comprising a housing,a rotor arranged i~side the housing and
constl-tuting in combination therewith a working chamber, a
means for charging the material together with a solu-tion o~
reagents into the working chamber, a drive sha~t and. i-ts
driving gear, wherein, according to the invention, the ro-
tor is made in the f'orm o~' a body of' rotation~ a portion of'
the surf'ace o~ which is intended ~or the repeated mechanical
compaction o~ -the material treated, while -the drive sha~t
~ .,
1 ~890~ -
-- 8 --
has unbalanced masse~ mou~ted thereupon and the shaft itsel~
i8 rot~abl~cou~ to the rotor or to the housing.
Due to ~uch a desig~ the rotation of -the dri~e shaft
provided with the unbala~ced mas~es creates a centri~ugal
force which cause~ the housing or th~ rotor coupled to the
drive sha~t via bearings to execute wobbling, as ~ result
of which the working ~urfaces o~ the housing a~d o~ the ro-
tor are brought in contact and rolled without slipping over
the layer of the material -treated in the worki~g chamber.
Hence, the material is arra~ged i~ parallel with the worki~g
surfaces and subjacted to the repeated mecha~ical compac-tion
across t~e ~ibers in the solutio~ o~ reagents wi~hout the
occu~cy o~ mecha~ical impaots bri~gi~g about the abrasion
or cutti3g of the pulp fiber~, which improves the ~uality ~f
the treated cellulose-co~taining material.
~ urthermore, due bo such a desig~ all o~ the material
bein~ inside the working chamber of the apparatus is subje-
cted to the repeated meaha~ical compaction, which increases
i~s output~ `
It is expedie~t that tho dri~e sha~t bogether with the
u~bal~ced mas~es ba mounted~ o~ baari~ side the rot~r
which in turn ba ~oupled to ~e ~ousi~g ~ia a spherical
joi~t" the lateral surfac0 of tha rotor beî~g intended ~or
the repeated mecharlical impact on the ma~erial treatad,
D~e to sllch a desig~l the e~ire struGtu:ee of tha appa-
ratu~; is made ~ompact. ~oreo~er, the arra~g~ment OI th~
balanced ma~sss i~side the ro~or precludsæ the a~pearaIlce
OI bendir~ mome~ts which might have o¢c~red had the ImbalarL-
1 1~8905
9 _
ced mass~s been arranged outside ths rotor and the dri~e~haft coupled to the rotor.
It is also expedient that the drive shaft together with
the unbalanced masses be mounted on bearings in a ca~ing
rigidly ooupled to ~he hou~ing, while the rotor be made in
the ~orm of a hollow cylinder a~d arranged inside the hous-
ing so as to be freel~ rot~.abl~. ~ mova~la radially, the la-
teral outer surface of the rotor being intended for the re-
peated mechanical impac~ on the material treatad.
Such a de~ign sîmplifies the ~tructure o~ the apparatus
and i~proves its operational re~iability since the rotor i~
this case i9 quite simple in design and has not ~y mec~ani-
cal coupli~gs with t~e housing, the relia~llit~ of which
with the presence o~ alter~ati~g loads is reduc~d~ ~urther-
more, tha free arrangement o~ th~ rotor i~ide the housing
en~ure~ that the compres~in~ ~orce acti~ on the matexi~l
treated is consta~ along the len~th of ~he rotor.
It is expedient that the rotor be made in the ~orm o~ a
hollow semisphere having its edges be~t outwardly~ a~d b~
ri~idly coupled to the means ~or charging the tr~ated mater-
ial toget~er with the solutio~ of reage~t~ into the worki~
chamber, ~a housing be providsd w~th a bottom and a stop
member ~or the rotor, ~hile the dri~e sha~t be mad~ hollow
and mounted on bearings on the a~oresaid mea~s for c~argi~
the material trea~ed, the be~t edge3 o~ tha semisphere bei~g
inte~ded for the repeat~d mechanical compaction o~ t~e mate-
rial treated.
1 15890~
-- 10 --
Due to such a desig~, to ~he shapa of the ro~or and
th~ provision of th~ bottom in the housi~g, the treatment of
the cellulos~-containing material is e~fected with its comp-
lete submexsion in the ~olution of reagent~, which ha~ a fa-
vorable e~ect on the quality o~ the treated cellulose-con-
taining material.
~ he objects as well as the ad~antages of the present
invention will become more appare~t from a con~ideration of
speci~ic embodime~ts thereo~ gi~e~ hereinbelow by way o~
example~ with re~erence being made to the accompanying draw-
ings, i~ whi¢h~
~ ig 1 illustrates schema~ically in longitudinal ~ec-
tion the proposad apparatus ~or the impleme~tation of the
mathod for the trea-tment o~ a cellulose-containing material,
according to the inv~ntion;
~ ig. 2 illustrates another e~bodiment o~ the proposed
apparatus; a~d
Fig, 3 illustratas sti}l another embodLme~t of the pro-
posea apparatus.
~ he proposed method is oarried out as ~ollows~
A callulo~e-containi~g material, such as wood chips,
is ~uppliod together with the ~olu~ion o~ reage~t~ i~to a
-
worki~g chamber reprsse~ting a~ annular ~pace betwQen a~
inner working bod~ and a~ outer working body embracing the
material. One of the working bodi~s i5 caused to wobbl~ and
to roll over the other worki~g bod~ through the layer of
the material treated i~ide the working chQmber. ~he wobbl-
ing nd rolling of on~ o~ the working bodi~s over t~e other
i~ en~ured by the rotation of a mass being unbalanced with
respect to the axis of rota-tion a~d~a-ta~y coupled to one
of the working bodies. ~he rolling of one worki~g body over
the other ~s a¢complished at that without slipping, as a re-
sult of which duri~g tha repeated mechanical compaction of
the material treated are e~oluded the forces causing its
abra~ion a~d destruction o~ the pulp fiber~O Due to the co~-
tinuous wobbling and rolling of one working bodg over the
other~ the woo~ chip~ e~tering the working chamber are ar-
ran~ed in parall~l with the surfaces of ~he working bodies
and subjacted to the mechaniaal compaction acros~ the fibars,
which is the optimum condition ~or obtaining the treated pro-
duct of superior quality. I~ the treatment process during
the time spe~t by the material treated inside the working
chamber in the aYerage from 5-to 30 second~ it is subjected
to ths compactio~ a few hundrod times. In order to a~sure
this, tha unbalanced mas~ inducing -the wobbling a~d rolling
of one working body over the other i~ causad to rotate at a
speed o~ about 10 to 50 revolutions per seeo~d.
The force of compression i5 chosen depe~di~g on the
purpose o~ treatment withi~ th~ range from a minimum value
not causing the commi~-tio~ o~ the material to a value ~u~-
~icie~t fo~ grindi~g the material. In each speGi~ic casa ac-
couat i~ take~ o~ ths purpo~e o~ treatm~t a~d of the phyæi-
cal and mscha~ical propsrtie~ of t}le material u~der treat-
me~t7 ~or example, the type o~ waod or other ~e~etable raw
material a~d the nature 9~ a precedi~g treatm~t. The
adjustment of -the compre~sio~ ~orce i~ ~imple and can be
89~
- 12 -
made by varying the speed o~ rotation of the unbala~ced
mass and its sccs~tricity.
The residence time of the material undar treatment in-
side the working chamber depends essentially on the ratio
of the material supplied ~or treatment and the solution o~
reagent~, ~he ratio, commonly ¢hosen from 1 to 3 to 1 to 20,
is u~ed for controlling the re~idence tlme o~ the material
treated in~ide the working chamber.
~ he treated material being under the ac-tlon o~ gravity
~d carr~ed by the solutio~ of reage~t~ entari~g simultane-
ou3ly moves inside the working c~ambar a~ the treatment pro-
cee~s and becom~s discharged there~rom~
~ he method for the treatmen~ o~ a cellulose-containing
mat0rial practiced according to the present i~ve~tion and
compri~ing t~e repeated me¢ha~ical compactio~ o~ t~o mate-
rial i~ the solution o~ reagents allows to increase the e~-
~icie~ey o~ the following operation~ in the ma~ufacture o~
pulp ~nd paper~
- the impregnatio~ o~ wood chips with the solution o~
cooking reage~s;
- the separation o~ tha vegeta~le ra~ material ~ub~e-
cted to chemical or thermochemica} processing in~o fiber
bundles or individual ~ibers;
- the gri~di~g of the fibro~s material ~or the produc-
.
tio~ of paper.
~ he results of the treatme~t of cellulose-co~aining
materials ar~ determined b~ the object pur~ued and al30 de-
pend on the type o~ a star~i~g material (for exampley the
:
1 1~89~5
_ 13 --
~ype o$ wood), the na*ure o~ a preceding treatment gi~en to
the material proc~ssed, and on the ¢onditions o~ carrying
out the treatment accordi~g to thi~ method.
~ he rep~ated meahanical compaction o~ the wood chips in
the solution of reagents accomplished according to the pres-
e~t invent-ion leads to remo~al of the air and moisture from
wood capillaxies at the mome~t oY the compaction of the
chips, and to absorption of the solution of cooki~g reagents
by the capillaries released at the mome~t o~ a pressure re-
lief. D~e to such a treatment ~hexe is achieved the impreg-
~ation of the wood chlps with the solutio~ o~ cooki~æ reag-
ent~.
As compared to other known methods for the impregnation
of wood chips with -the use of mechanical treatment, the pro-
posed method owing to the repeated cycleæ of compactio~ and
pre~sure relief enables to increase the uniformity and ¢om-
plete~ess o~ the impreg~ation of th0 chips and to reduce
the compressio~ ~orce applied thereto.
It is preferable that the for~e o~ compressio~ during
th~ procedure of impregnation should not e~ce0d the lLmit
of elasticity of the material breatsd, but sometimes i~ the
impregDation o~ a particularly hard-te~turad material (~or
e~mple, birch chips) it is advisable to go somewhat beyo~d
the limit of elasticity o as to ensure ~ull impregnationO
The ar~angement o~ chips i~ parallel to th~ compressiDg
surfaces~ while treati~g them according to the proposed ma
-thod, results ~ot only in that the compressio~ o~ the chips
is alwa~s ef~ected across the ~ibsrs, rather ~han alo~g ~hem,
the latter being the mo3t hazardous direction from the Yi8W-
1 1589~5
- 14 -
point of pulp fibers safety, but also in that -t~is takes
place in the absence of forces causing the abrasion or cutt-
ing of the fibers. All thiæ permits to intensi~-g significan-
tly the impregnatio~ of the chips with the solution of cook-
i~g reagents as well as to improve its uniformity without
damaging the pulp fibers.
Durin~ the treatment process ac¢ompanied by -the numero-
us repati~io~ of compressio~ and pxessule relie~ ¢ycles, the
chips may become partially destroyed~.In this case, however,
the deætr~ction com~s about wnder the action of compression
forces dirscted across the fibe~s, these forces being o~ the
~lighta~ danger from tha ~ie~poi~t of fiber safety. Some
partial destruc~ion o~ the wood chips obser~ed ln experimen-
tal testing of the proposed method was attended b~ the for-
mation o~ longitudinal crack~ in the chips followed by their
di~isi~n into separate "matches" without shortening of the
material and ~ithout the ~ormatio~ of a considerable amount
o~ sawdust.
Owing to that t~e trsatment of pulp materials according
to the proposed method is ~ot accompanied by the destructio~
~ the material there iæ achisved an i~oreas~ in the q~ality
o~ the obtained pulp ai well as saving i~ the electric power
required ~or ~ulfilli~g the treatmsnt process.
~ he applicatio~ of the proposed method for the treat-
ment of a c~llulose-conkai~i~g m~terial makes it possible
not only to e~sure its e~peditious ~nd uniform i~pregnation
with the ~olution o~ chemical~, but al~o ke speed up ¢onsi-
de~ably the succeediD$ proces~ o~ extracti~g pulp from the
~ 15~9~
vegetable raw matsrial, i.e. the cooki~g o~ -~he pulp. ~he
i~tensi~ication of the cooking procedure is sacured due to
the mechanical a~d chemical activation of the starting mate-
tial with respsct to the cooking rea~e~ts. The repeated com-
paction o~ the cellulose~co~taini~ material to~ether with
ths s~lution of chemicals, a~ provided b~ ths propo~ed meth-
od, aGtivates the macromolecules o~ the components in the
vegetable raw ma~erial, resulting in a sub~tantial increase
in their chemical interactio~ with the cooking chemicals.
~he combined impact o~ rapeatedly applied compression ~orce~
coupled wibh the che~ical action o~ the cooking chemicals
leads to that li~nin con-tained in the Yegetable material
becomes oblitsrat~d and dissolved much ~aster than in the
cooking of the material ~ot subjected to th6 mechanical tre-
atment as de~cribed hereinabove. Such a combi~ed impact on
the ~egetable raw material not only accelerates the dissolu-
tio~ o$ ligni~, but also conduces to a reductio~ in the con-
~umptio~ o~ chemicals required for the cookingO O~ing to
this, the applicatio~ o~ the proposed method i~ the manufa-
~cture of pulp allow~ to decrease th~ dura-tion o~ the process
to cut down the con~umption of chemical~ a~d power ~or the
cooki~g and to e~hance the chemical purity of ths pulp obta-
i~edO
A~ wa~ already m~ntioned hareinabove~ the repeated me-
chanical compaction o~ the cellulose-containing material
eYfected according to the prop4sed method ma;y be accompanied
by the separation of the material tr~ated into ~iber bu~dles
or i~dividual fiber~ The desired degxee o~ disi~tegration
.
.
~ 05
- 16 -
o~ the material i8 a-ttained by choosing -the force and frequ-
enc~ o~ the compression applied to the ma-terial or ~y relax-
ing fiber-to-fiber bonds in the cellulose-containi~g mater i
al by means of pretreati~g it with reagents causing the in-
tercellular matter to be~ome partially dissolved or plastif-
ied and tha ~iber-~lber bonds to weaken. ~he separation o~
cel~ulose~con-taining materials into fibers is widely used in
the manufactura of semichemical pulp~ hi~h-yield pulp9 chemi-
-me¢hanical or thermo-chemi-mechanical pulp, as well as in
vari~us stag~-by-stage mathods, e~isti~g or being daveloped~
for producing pulp wit~ the i~tarmediate gri~ding o~ ~he pulp
between the stages of the process~
In bhe overwhelming majority of existing methods for
producing fibrous pulp, the separation of ~egetable materi-
als into ~ib~rs is accompanied b~ grindi~g in cyli~drical,
conical or disk mills of di~ferent designs~ The gr~ding of
the material on a disk mill ~akes placa upon its pa~sage
between two di~ks, one of which is rotati~g a~d the other is
motionless or rotati~g in the opposite directio~ the sur~a-
ce Qf these disks bei~g provided with k~ivss and ~rooves.
I~ the grindin~ process wi~ the use OI k~ife mills the
material sapa:rated is subjected ta the variegat~d actio~ o~
~he grinding tackle, i.e. to the percu~iorl o~ the knives,
~hearing, cuttix~, t~lvisti~g a~d abrasion~ As a result of
this action-o~ the gri~di~ di~ d urlder the ef~ect OI
deIormations occ~g at that" the fibers unde~go damage and
rupture. ~he un~a~orable action o~ the ~ibers is e~anced in
coDseque~ce o~ that the material (chips~grou~d pa~etrates
1 1 5~
_ 17 --
into the space between the grin~i~g disks i~ th~ form of
separate indep~ndent bodies arranged loosely i~ dif~arent
posi~ions and in an unoriented ~ashion with re~pect to the
kniv9s of the ~rinding disks. r~he sharp edges of the knives,
the rigidity of the ~tructure u~ed and the hi~h unit pressu-
re applied to the working surfaces conduca to cutting of the
fibers. ~he use of the fibrous pulp thus obtained in the ma-
nufacture o~' papex and cardboard leads to a considerabla re-
ductio~ o~ the mechanical strength of a finished product.
~esides, thH undesirabla damage of the ~ibers al~o causes
the increased consumption of power raquired for this opera-
tion~ ~he unproducti~e expe~ditures of power in t~e treat-
ment o~ the material o~ the disk mill al~o arise due to im-
mense energy losses for o~ercoming the hydraulic resistance
upon the rotation of the knifa disks and also for the trans-
portation o~ ths material treated.
The struct~re of the kni~e mills in use su~fers from
~nothex es~ential disadva~tage residi~g in the vulnerability
to the penetration o~ axtra~aouæ solid inclusions. The metal
or ceramics findi~g its way into the mill in~lict great da-
mags to the kni~es and may re~der tha mill inoperative. ~he
subseque~ sharpening of the kni~es takes considerable time
resulting i~ the downtim~ of the e~uipment.
~ he optimwm conditions of treating ~egetable material~
accordi~g to the proposed met~o~ can be establi~hed in each
~pecif ic case b~ choo~ing the shape of ths bod~ o~ rotatio~,
by decreasing or increasing the force of cru~hing tbrou~h
the exte~t of the unbalanced mass, the speed o~ its rotation
90.S
- 18 -
or the residence time of the material in the treating zone.
By varyi~g the above conditions or b~ repeating a simi-
lar treatment there can be achieved not only the separation
of the material trea~ed into individual ~ibers, but also en-
sur~d its further grinding to the desired degree o~ fineness.
r~he proposed treatment method can also be employed for
grinding pulp and other ~ibrous intermediate products in the
production of paper therefrom.
~ he treatment of the matsrial according to the proposed
method does not i~volve ths unproductive e~penditures o~ po-
wer associated with the rotation of th~ grinding disks ar-
ranged in pro~imit~to each other and provided with knivas.
~he tra~sportation of the material treated is accomplished
under the ~orce o~ graYity and does not require an~ power
consumption. ~hese adva~tages enable to cut down the con-
sumption of power ~or the treatment.
Ths proposed method for the produc-tion o~ ~ibrous in-
termediate products precludes the harm~ul con~e~ue~ces for
the equipme~t attended by the penetration of e~tranaous- so-
lid objects into the apparatus since in -t~i~ case there is
no rigid coupling between the elements acting o~ the mate-
rial bei~g ~ro~d.
~ he method under consideratio~ will be ~urthex illust- -
rated hereinbelow by its speci~ic embodiments.
xa~e 1
- 2 kg of aspen chip~ were conti~uousl~ charged into the
apparatus and a 14% solu~ion o~ sodium hydroxida in the
weight ratio of 1 to lO was supplied. ~he d~ration o~ the
- alss~o~
- 19 -
continuous charging o~ the chips and the solution amounted
to 2 min. ~he rotation frequency o:E the drive shaft was
1480 rev/min. ~he approximate residence time of the chips in
the working chamber was 15 ~ec and the requlsite average num-
ber of chips oompression cyclos was 370. Su~sequ~nt to the
treatm~nt according to the method, tha impregnated chips
were separated on a screen from ths ~reely dripping solution
~nd a portion thereof was placed i~ an autocla~e and heated
at a temperature of 160 to 165C for 1 hour and a half. ~he
cookad pulp was washed with water~ sorted and air-dried~
The yield and ~uality indexes were determined~
Yield from wood~ % . . . . . . ~ . 50.5
~ignin co~tent, % . . . . . . . . 1.3
Breaking length, m . ~ ~ . . . 0 9170
Folding resistance, nwmber ~
double folds . . ~ . ~ . . . . . 2320
E~ample 2
~ he treatment o~ 2 kg of birch chips was effe~ted as
described i~ Exampla 1 ~imulta~eousl~ ~uppl~ng into tha
apparatus a 16% solution of sodium hydroxide i~ the weight
ratio of 1 to 10. ~he duratio~ of the conti~uous char~ing
o~ the chips and the æol~tio~ was 1 mi~ 40 se~. ~he rotation
~rsq~ency o~ the drive sha~t was 2850 reY/min. ~he appro~lm-
ate residence time o~ the ehips i~ the apparatus wa~ }1 sec
and the requisite avexaga numbar o~ chips compressio~ cycles
was 5500 Subsequent to the treatment according to the method,
the impregnat~d chips wsre separated on a scree~ from ~he
e~ce~s of the solution and a portio~ thereof was subjected
`"` 1~5~
20 -
to cooking in the autocla~e at a temperature of 160 to
165C ~or 1 hnur and a half.
Pulp ~ield, % . . . . . . . . . . . . 48.3
~igni~ co~tent, ~0 . . . ~ . . . 0.8
Breaking length, m . O . . . . . O . 9430
Folding resistance~number of
double ~olds . . . . . . . . . . . 2840
Exam~le ~
Bi~ch chips were preheated with a 2% solution o~ qodium
hydroxide *Qr 1 hour and a hal~ at a temperature of 100C,
wherea~ter the pulp waæ subjected to the repeated mechanical
compactio~ according to the method, substa~tially as describ-
ed in ~xamples 1 and 2. The rotatio~ ~requency o~ the dri~e
shaft ~as ~100 rev/mi~. ~he treatment was repeated 6 times
with in-termediate washing after the ~irst passage, and ~ith
~he extraction of the pulp after tha second3 fourth a~d
sixth pasqage through the apparatus. ~he extracted samples
o~ the pulp were washed and the beating degree a~d mechanic-
al strength i~de~es were determined.
Wood residue yield a~tar ¢hemical
treatment 7 ~ o 9
Indexes ob~ai~ed a~ter the second pass-
ing of the pulp t~rough the apparatu~:
beatin~ degre0 . ~ . . . 23
breaking le~gth, m . . ~ 350
foldi~g~resista~ce, ~umber o~
double folds . . 0 9 . O . . . . 18
bursti~g strength, kg/cm2 ~ . . . 1.5
` ~5~5
~ 21 ~
Inde~as obtained after the fourth pass-
i~g of the pulp through the apparatus:
baating degree . . . . . . . ~ . . . 35
breaking length, m ~ 0 . . ~ . . 0 . 5860
foldin$ resistance, ~umber o~
double ~olds . . r ~ 104
bursting stre~gth, kg/cm2 . . . . . 2.2
Indexes obtained a~ter the sixth ~a~s-
i~g o~ ~he mass through the apparatus:
beating degree . . . . . . . . . . . 60
breaking l~gth~ m ~ . . O . . ~ . . 7020
foldi~g resistance~ number o~
double fold~ . . . . 0 . . . . . . 27~
bursting strangth, kg/cm2 . . . . 2.9
Example 4
Birch chips were pretreated with a 2~o solu~ion o~ sod-
ium oarbonate ~or 1 hour and a half at a tempe~ature o~
100C, wharea~ter tha pulp was subj~ctad to tha repsated
mechanical compaction accordin~ to the method, æubstantial
ly as describad 1~ Example ~.~ he ro~a~i~n ~reque~c~ o~ the
dri~e ~ha~t is 2100 rev/mi~. ~hs pulp was passed through
the apparatuB thr~a:times with i~t~rmediat3 washing~a~tsr
the ~ir~t pa~sLng.
Wood residue yield after chemical
tr~atment~ % ~ . O ~ . 92~1
Beating d~gree . . ~ 0 ~ 30
Braaking le~gth9 m . . . . . . . . . 5550
Foldi~g resistance, n~mber of
double ~old~ ~ ~ . . 0 . . . . . 0 . 73
- 22 -
~earing rssistance . . . . . O . . . . 60
Bursting stre~gth; kg/¢m2 . ~ . . . . 2.2
~3~a~
Aspen chip~ wexe prcaonditioned in a 5% solution of am-
mo~ia ~or 12 hours at room temperat~re, whereafter it was
subjected to the repeated mechanical compaction according to
the method, substantially as de~oribed in Exampl~ 3. ~he
rotatio~ freque~cy o~ the driva sha~-t was 2100 rev/mi~.
Wood residue yiald after chemical
t~eatmen~, % ~ . . . . . . . . , . 0 96.2
Degree of grin~ing~ . . . . . . . . ~ 60
Breaking length, m ~ O . . . . . ~ ~ 6400
~olding resistance~ number of
double folds . ~ . . . . . . . . . ~ 1~2
~aaring resistance~ . . . . . . . ~ 42
Bur3ting stre~gth, k~cm2 . . . ~ . . 2.6
~xa~le 6
~ aqueous suspension o~ unbleached sul~ate pulp was
prepared from pi~e i~ 10% co~centration and pa~s~d through
tbLe apparatus Ior the repeated mecha~ical co~pactio~ accQrd-
i~g to the pr~posed msthod. ~h~ rotatie~ ~requency of the
drire s~aft was 2100 rev/mi~. ~he i~de~ss o~ the mass obtai-
ned after the sixth passi~g through the apparatus ~ere as
~ollow~.
Beating degree . . . . . . . . . ~ . . 48
Breaki~g length, m . . . . . ~ . ~ . . . 9150
~olding resistance, ~umber of
double fold~ . . . . 2890
9~
- 2~ -
Example 7
Bleached pulp cooked in nit.rate was subjected to the
treatme~t according to the proposed me-thod, substantially
as described in Example 6. The indexes of ~he mass obtain~d
a~ter the sixth pas~i~g throu~h the app~ratus wer~ a~ fol-
lows.
Bea-ting dagree ........................ 58
Breaking length, m . . . ~ . . . . . . ~ . 6880
FoldiD~ resistancs, ~umber of
double folds . . . . . . . . . . . . . . 47~
~ he appara-tus for practising the proposed method compr-
ises a housing 1 /Fig. 1/ mounted on a foundation 2 by means
o~ flexible shock absorbers 3. Arranged insids the housing 1
is a rotor 4, which in combination with the housing 1 defin-
as a working chamber 5. ~he housing 1 is provided with a me-
~8 6 for charging the cellulo~e-containing material -togeth-
er with the solution of reagents into the working chamber 5.
~he apparatus also comprises a drive sha~t 7 with unbala~c-
ed masse~ 8 moL~tad thereon so that the eccentricity of
their mass i~ adjustable~ The drive shaft 7 is coupled via
a flexible coupling 9 to a drivin~ gear lO. ~he rotor 4 is
mada i~ the ~orm o~ a bod~ of rotatio~, the o~ter lateral
sur~ace 11 o~ which is i~tsnded for ropflatedly mecha~ic~lly
compacting ~he material u~der trea~e~t~ th~ ~aterial treat-
ment baing dispo~ed between tha ~utor lateral sur~ace 11 o~
the rotor 4 and the inner surfa~ 12~ o~ the housing 1.
According to on~ of the embodiments of tha apparatus,
the rotor 4 is coupled via a hoIlow rod 13 and a spherical
'~ :
~ 1~8~5
- 24 ~
bearing 14 to the housing 1. The drive shaft 7 with the un-
balanced mass~s 8 is mo~nted on bsarings 15 inside the rot-
or 4. ~hus, in this specific embodiment of the apparatus
the drive sha~t 7 with the unbalanced masses 8 is coupled
ta the rotor 4 and due to it~ mou~ting in -the bearings 15
is capable of ~ree rotation with respect thereto~
Accordi~g to a~oth~r embodiment of the apparatus, it
al~o comprise~ the housing 1 /~ig. 2/ mounted on the founda-
tio~ 2 by means of the flexible shock absorbers 3 and incor-
poratin~ therei~side the rotor 49 the aforesaid rotor 4 and
housing 1 de~ining in combi~ation -the working chamber 5,
~ho housing 1 is provided with the means 6 for charging -the
material treated together with the ~olutio~ o~ reagents i~-
to the working chamber 5. ~he apparatus al~o compri~es the
drive shaft 7 with the ~nbalanced masses 8 mou~ted th~raon,
the aforesaid drive shaft 7 being coupled ~ia a flsxible
couplin~ 9 to a driving ~ear 10.
~ partic~lar ~eatur~ of this embodime~t of the appara-
tus resides in that the drive shaft 7 with ths u~bala~ed
masseæ 8 is mounted o~ baarings 15 within a casing 16 rig- :
idly coupled via ribs 17 to the housing 1. Thus, in this
speci~ic embodimant o~ the apparatus the drive sha~t 7 with
the u~bal~nced masses 8 is coupled to the housing 1 and~due
to its mountinæ in the baaring~ 15 i8 capable of ~ree rota-
tion with r~pact th~reto. The r~tor 4 i~ mad~ i~ the form
o~ a hollow cylinder ~hich is freely mounted inside th~
housing 1 a~d supported by th~ ribs 17. Dua to this, the
rotor 4 is capa~le of free rotation and radial moveme~
1 ~5~9
-- 25 _
sid~ the housing 1~ the outer lateral surface 11 of ~he ro-
tor 4 and tha i~ner sur~ace 12 o~ tha housing 1, as in the
embodiment considered hereinabove, being intended for repe-
atedly mechanically compacting the material treated.
Aocording to still another embodiment of the apparatus
and similaxly to its other embodiment~, it also comprises
the housing 1 ~Fig. 3/ mounted on the foundation 2 b~ means
o~ the flexiblo shock absorbers 3. Arranged inside thq hous-
i~g 1 iæ the rotor 4~ the a~orasaid rotor 4 defining i~ com-
bi~ation with the housin~ 1 a workin~ chambor 5. The appara~
tus also compriseæ the drive sha~t 7 with the u~balanced maæ-
s~s 8 mou~ted thereon, the a~ore~aid drive shaft 7 being co-
upl9d to the driving gear 10.
A particular ~eature o~ this em~odiment o~ the appara-
tu~ xesides in that the rotor 4 is made i~ the ~arm of a
hollow semispher~ having its edges 18 be~t out~ardly. The
housing 1 is provided with a bottom 19. ~ou~ted on a cover
20 of the housi~g 1 is a stop member 21 for the rotor 4 hav-
i~g a concave spherical surface. The driv~ shaft 7 with the
unbalanced masse~ 8 is mada hollo~ a~d mounted i~ bearings
15 on the mea~3 6 ~or charging the material trea-ted which~
i~ turn9 is ri~idly coupled t~ the rotor 4. ~hus, in this
specific em~odiment of the apparatu~ the drive shaft 7 with
the unbala~ced masse~ 8 is coupled to the rotor 4 a~d due to
its mou~ti~g i~ the bearings 15 i~ capable of froe rotation
with respect thereto. ~he outwardly bent edges 18 of the se-
misphere serve for repeatedly mechanic~lly compacting the
material u~der treatment whichis dispos~d betwsen the outwar-
a 1589~5
_ 26 -
dly be~t edges 18 of the semisphere and the inner sur~ace 12
of the bottom 19 of the housing 1.
~ he apparatus operates as followsO ~he torsional moment
~rom -tha drivi~ gear 10 /Fig. 1/ via -the flexible coupling
9 and the drive sha~t 7 is -transmitted to the unbalanced
masses 8, who~e rotation produces centrifugal ~orce tra~s-
mitted via the beari~s 15 to the rotor 4, which starts to
deviate from the lo~gitudinal axis of the housing 1 a~d to
per~orm circular oscillating motio~s arou~d the center of
the spherical joint 1~ coupling the rotor 4 to the housin~ 1.
In other words, the rotor 4 is caused to perform wobbli~g
motions. I~ this process the oute~ lateral surface 11 of the
rotor 4 comes in contact w~th the i~ner sur~ace 12 o~ the
housing 1 and the rotor 4 is caused to roll over this surfa-
ce rotating according to the law of pla~tary rotation tow-
ard the side oppo~ite the direetion o~ rotatio~ of its axis
and of the drive sha~t 7 with th~ unbalanced masses 8.
The material to be treated is charged together wi-th the
solutio~ of reagents via the mean~ 6 into th~ working ~hamb-
er 5 of the apparatus, wherein it is arranged in a uniform
layer between the outer lateral surface 11 o~ the rotox 4
and the i~ner suxface 12 o~ ~he housing 1
Due to the annul~r shape o~ the worki~g chambex 5 a~
well as to the wobb-ling motion a~d rolling o~ the rotor 47
the material treated, for example~ wood chip~, is arra~ged
in parallel with the sur~ace 11 o~ the rotor 4 and with the
surface 12 o~ the housing 1~ a~ a re~ult o~ which the ~orc~s
of compres~ion are directed across the ~ibexs and the chips
ara subjected solely to the repeated mechanical compaction.
9~
- 27 -
~ he operation o~ the apparatus according to the embo-
diment illustrated in Fig. 2 proceeds similarlyO ~he dif~e-
rence being in that the centxifugal force arising upon the
rotation of the drive shaft 7 with the unbalanced masses 8
is transmitt~d via the bearin~ 15 and the ribs 17 to the
housing 1 cau~ing its wobbling motions, In othar words, the
hou~ing 1 starts to deviate from the origi~al positio~ and
to perform cir¢ular oscillating motio~. Upon contact of
the inner surface 12 of the housing 1 with the outer later-
al sur~ce 11 o~ the rotor 4, due -to its inertia, it is ca-
used to roll o~er the inner surface 12 of the housing 1~
The operatio~ of the apparatus according to the embo-
dimant illustrated in Fig. ~ pro~eeds similarly to that of
the embodiment illustrated i~ Fig. 1. ~he difference being
in that the ce~tri~ugal force arising upon the rotation of
t~e hollow dri~e sha~t 7 with the unbalanced masse~ 8 is
tra~mitt~d to the rotor 4 via-the means 6 ~ox chargi~g th~
material to be tr~ated to~ether with the solution of reag-
ents into the working chamber 5, the rotor 4 being caused
to roll by the outwardly bent edges 18 over the sur~ace 12
o~ the bottom 19 o~ the housin$ 1, aæ a result o~ which
upo~ c~ar~in~ of the material together wi~h the solutio~
of reagents into ths working chamber 5 the material is
subjacted to the repeat~d macha~ical compaction~
Owing to that in all of the above-co~sidered embodim-
en~s of the apparatus the drive ~haft 7 with the unbala~c~
ed ma~ses 8 ~reely rotate~ o~ tha bearings 15 with respect
to the rotor 4 (~ig~. 1 a~d 3) or with respect to the hous-
8~
- 28 ~
ing 1 ~Fig. 2), the material upon rollin~ of the rotor 4
wer the surface 12 of -t~e housing 19 .i~ subjected solely
to the repeated mechanical compaction without the occu~ence
of an~ ~orces causin~ abra~ion or cutting of the pulp fibersO
~his is attributable to that rolling of thq rotor 4 i~ cau-
sed not by direct tra~smissio~ o~ the torsion~l moment Yrom
the dr~e shaft 7, but results from contact of the housing
and the rotor upon the wobbling motions of one of them un~
der th~ action of the centrlfugal force of the rotati~g un-
balanced mass~s 8. ~his improves signi~icantl~ the quality
of the tr~ated material.
Due to ~hat all oP ths mat~rial disposed in the working
chamber is subjected to the repea-ted mecha~ical compaction,
the output of the apparatus is thereby l~creased.
The forco o~ compressio~ applied by th~ rotor 4 to tha
.. .
layer of the material under treatme~t is governed b~ the
mass of t~e unbalanced masses 8~ by the ang~ular spesd of
their rotation and the eccexLtricit~sr of the mass of ths u~-
balanced mass~s 8 with respect to the axis of thsi:L ro~a-
tio~ and is detexmined from the formula~
m w2 . R
where: m i~ the ma~ OI the ~balanced ma~ses,
w is ~he a~ular ~peed of rotatio~
R is the eccent:~i¢ity o~ the mas~ OI the unbalanced
massas with respact to the axis of rotatio~O
T~e eutput of the ~pparatus a~d the qualit~ of Ehe ma-
terial treatmant depends on tha choice of ths~s p~amoter~.
Dus consideration is also to be gi~en to tha type and pro-
~ 15~9~5
_ 29 _
perti~s of the material -to be treatad. Th~ for~e of compres-
sion i~ this apparatus is readily adju~ted by Yaryi~g the
ecc~ntricity of th~ mass o~ the unbalanced masses 8 and the
a~ular speed of -their rotatlon.
~ or reasons enwmerated hersi~above tho proposed appa-
ratus can be succ~8s~ully exploited ~or the treatme~t of
cellulo~e-co~taining materials ~ith -t~e view of impregnat-
ing them with the solutio~ of cooki~g reagen~s with a grea-
ter or smaller degre~ o~ fiber-to-fibsr bonds relaxatlon~
for ths separation of chemically or thermoch~mically pretre-
at~d materials into fib~r bundla~ or individual ~ibers, or
~or the beating c~ pulp in the pxoductio~ of paper stock.
~ rom the foregoing spacific embod~ments o~ ~he pressnt
i~ve~tion, ~n0 skill~d in the art can easily ascertai~ the
essential characteristics of this inve~tio~9 and with~ut
departing from thq spirit a~d scope ther~of, ca~ make vari- -
OU9 changes and modifications ~f the inventio~ to adap~ it
to various u~ages a~d condi-ti~n Conseque~tly, such chan~-
es a~d modifications are properly, equitably, and inben~d
to b~, within bhe ~ull range o~ ~qui~alence of the ~ollow-
irlg claims.
The advantages of th~ present Lnve~tion, as compared
to all of the prior art msthod~ and ap~aratu~ for the tre~
atment of a csllulose-containi~ material, reside in the
followings
- the propo~qd method and apparatus improve the quali-
ty o~ the tr~ated material, w~ich, i~ tur~, improve~ the
qualit~ o~ thq pulp, paper and cardboard obtained t~r~-
*rom;
i 15890
- 30 -
- the propo~d method a~d appara~u~ enable to dscrease
the co~umptio~ of vege-table ra~ material and chemical re-
agen~s;
- the proposed method a~d apparatus enable to speed !"
up ~he proces~ of pulp pro~uction;
- the propo~ed method and apparatu~ enable to cut down
the con~umption o~ power;
- the propo~ed method and apparatu~ ~eature an increas-
cd output a~d operational reliabllity~
In support of the hig~ afficie~cy inherent in the pro-
po~ed method ~d apparatus there is ~iven hereinbelow a
comparativ~ tablo pre~nti~g the i~dexes of tha pulp pro-
duct~ obtainsd with the u~e of the prasent method and appa-
ratu~ ~ersus those obtainad i~ accordance with the most wi-
dely spr~ad production practice exi~ti~g currently.
~able
Indexe~ Propo~d method ~ tlng methods
~ype o~ wood aspe~ birch birch a~p~n bir¢h birch
Yield ~rom wood a~-
ter chemical treat-
ment, % 96 90 90 90 86 86
:Bsating degrea 60 30 60 60 30 60
Indexes of mechanic-
al s~rength with pa-
per mass o~ 75 g/m ~
breaking l~gth,m 6400 5800 7020 6300 5600 6800
tear resistanc~ 42 60 - 40 45
bursting strength,
kg/cm 2.6 2~2 2.9 2.2 1.9 2.6
.~
9~5
~able (cont.~
IndexesProposed method ~xi~ting methods
~ype of woodaspen birch birch aspsn birch birch
. .
~olding resi~t-
ance, number of
double folds 132 10~ 273 9 12 80
. . . _ . _
Power consump~lon
~or beating to 16
kwhr/t 5 - 7 200 - 400
_ . . . . . . " , . ., _ , ,
