Note: Descriptions are shown in the official language in which they were submitted.
1058819
l'his invention relates to stripping Or pulp bales, i.a. in manu-
facture of rlufr for dlapers and similar sanitary products. Such
products are at present made startin~ from Q band-shaped chemical
pulp in rolls, which pulp is fed into a mill, usually Or hammer
type, breaking the band so that the fibers are made rree. However,
for economical reasons attempts have'instead been made to start
from a chemical sheet pulp or mechanical pulp, ~hich is cheaper.
However, the means known so f~r for defibration of pulp result
in a considerable shortening Or the fibers reducing the quality
o of the final product.
For stripping whole pulp bales two difrerent strlpping means have
so far i.a. been used. In one Or these (Swedish patent specirica-
tion 355 613) the bale is cut transversely to the direction Or the
sheets about 3 cm from the front edge Or the bale, after ~!hlch
the strips obtained in this way are defibered by means of two mills.
In the other stripping means (Swedish patent 334 811) the sheets
the bale are stripped by means of a plurality Or toothed stripp-
~ ing rods arranged below the surface of the lowermost sheet.
,~ ~ In the first-mentioned stripping means known a certain shortening
, ~o Or the fibers is obtained by the cutting- In the other stripping
, means a shortening of the fibers is obtained when the tools saw
into the sheets from their surface.
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,l~ It is the object of the present invention to achieve,a coarse
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10588~9
deribration of` whole bales, especially such Or slab type, an
optimization of the ri ber quality bein~ obtained because working
is effected the whole time with tools without edges, operating
contrary or obliquely to the feed direction of the riber layers.
The invention relates to a stripped product with no or little
destroying Or the f;bers as a consequence of the workin~. The
machine of the invention is intended to be combined with one
additional defibration step to obtain a comple~e defibration.
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~Here a so-called flake-dried pulp in bales is intended by bales
~o of slab type. Such pulp is substantially produced in the follow-
ing ~ray. The diluted pulp suspension having a concentration Or
3-5 % is pumped to a wet machine. In this the pulp is dewatered on
a roll screen or rlat wire with ~ollowing presses or else directly
in a press nip to 45-50 % dry content. Then the pulp bale is de-
fibered in a fluffer and the flu~fed pulp is conveyed pneumatical-
ly to a drying apparatus. The dryin~ can be divided into two or
~ore steps. The flufred wet pulp (the flakes, the riber agglomerate~
are then separated in a wet pulp cyclon and rall down into the
, ~ injector o~ the first step. The pulp is mixed here with hot ~ryin~
gases and is transported under drying via a fan and a drying line
to a drying cyclon, ~here pulp is separated and falls down into
the second drying gtep. In the following drying step the process
is repeated, arter which the finally dried pulp ralls down into a
cooling step. From this the pulp is conveyed pneumatically to a
slab press.
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The sla~ pr~ss comprises a form, into ~hich the fiber agglomerates
rall down. When a certain amount of fiber agglomerate has been
supplied to the form, the supply is stopped, and a press plate
with the internal dimensions of the rorm is pressed down into
the form and presses the fiber agglomerates together. The press
plate is lifted and a new amount of fiber agglomerate is filled
into the form to be compressed anew by the press plate. This
process is repeated until the contents of the rcrm have reached
a height of 8-12 cm, when the contents of the form aré removed
o in the ~orm Or a disc.
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Thus, at each pressing operation a new fiber layer has been formed.
These fiber layers are well visible in the outer edges o~ the
finished disc ~plate). E~ch layer consists of hard compressed and
flattened fiber agglomerates. Usually 4-6 Or s~ch discs are placed
upon each other, after which tùey are additionally compressed in
a conventional bale press to a bale having a weight Or 200-250 kg,
which will then have a volume weight Or about ôO0 kg/m3.
If one intends to disintegrate such a b~le it will be found that
the slabscan easily be separated from each other. It is much more
)
~o dirficult to disintegrate a certain slab. This is done most easily
~ if a knife-blade or the like is inserted bet~reen two superficially
;~ lying fiber layers and the disc is stripped from above layer by
layer. Therefore the working according to the invention is i.a.
. . .
carried out in accordance with this method. When a bale with
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1058819
horizontally lying discs is fed towards the working tools of
the invention, the uPPermost iber layer of the uppermost
disc will first be hit by the stops of the tools, If the upper-
most fiber layer is at the same height over the conveyor
- belt as the tool tip, when the latter is ln a position
vertically to the shaft center, the tool tip w~ll strike against
the horizontally placed fiber layer against the feed direction
of the layer. However, if the uppermost fiber layer is at
the same height over the conveyor belt as the tool tip, when
the latter is at the same height as the shaft centre, the tool
tip will expose the fiber layer to a stop almost straight fr-om
below and lift it upwards. All the other stopping angles are
included between these two extremes.
The invention will be described below more in detail
in connection with the enclosed drawings showing an embodiment
of a machine for carrying out the method. Fig. 1 and 6 show a
~ide vlew of a machine according to the invention, Fig. 2 and 3
the working tools, Fig. 4 the profile of the pulp bale against
the tools in working and Fig. S a detailed drawing of two
shafts with tools (6, 7) and stops (23).
~ n one aspect of this invention there is provided
a method of stripping a pulp bale, comprising the steps of:
relatively moving a first tool and a surface of the bale
against each other to strip pulp from the bale by forming a
plurality of parallel grooves in said surface, eacn groove
being defined by opposing sidewalls; and relatively moving
a second tool, having a different profile from that of the
first tool, and said surface of the bale against each other
to strip pulp from the bale by contacting the opposing side-
walls of the parallel grooves.a method of stripping pulp b~les, comprising the steps of:
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1058819
convey~ng a bale along a path toward a stripping means which
comprises at least one shaft having at least one first tool
pair extenaing therefrom, one member of æa~d first pair having
a narrow angle tip and the other member of said first pair having
a wide angle tip; said shaft having at least one second tool
pair extending therefrom, one member of said second pair having
a narrow angle tip and being positioned to follow the other
member of said first pair as said shaft rotates and the other
member of said second pair having a wide angle tip and being
positioned to follow the one member of said first pair as said
shaft rotates:
rotating said shaft so that said tool pairs contact said bale
in a direction opposite to the direction of bale movement:
stripping pulp from said bale with said at least one first tool
pair and said at least one second tool pair by forming grooves
in said pulp bale with said at least one first and second tool
pairs, said grooves having ridges therebetween;
displacing said ridges alternately back and forth as said wide
and narrow angle tips are moved alternately past opposite sides
of said ridges, whereby ~aid ridges are broken away from said
bale.
In a further aspect of this invention there is pro-
vided an apparatus for stripping a pulp bale comprising means
for conveying the bale against stripping tools acting on
essentially the whole surface of the bale facing said tools
characterized in that the stripping tools comprise a first group
for forming a plurality of parallel grooves in said fiurface and
a second group for contacting side walls of said grooves.
In a still further aspect of this invention there is
provided means of stripping pulp bales, comprising:
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1058819
means for conveying pulp bales along a path,
at least one shaft mounted for rotation above said conveying
means and oriented transversely to the dtrection of movement
of said conveying means,
at least one first tool pair extending from said at least
one shaft, one member of said first pair having a narrow angle
tip and the other member of said first pair having a wide angle
tip, and
at least one second tool pair extending from said at least
;~ 10 one shaft, one member of said second pair having a narrow
angle tip and being positioned to follow the other members of
said first pair as said shaft rotates, and the other member of
said second pair having a wide angle tip and being positioned
to follow the one member of said first pair as said shaft
rotates:
whereby said tool pairs form parallel grooves in said bale,
said grooves having ridges therebetween, said ridges being
displaced alternately past opposite sides of said ridges, thereby
; :breaking said ridges away.
In Fig. 1 a machine according to the invention i8
shown for stripping bales 1 consisting of slabs 2. These
bales 1 are fed by means of a conveyor belt 3 towards a stripping
means, which as a whole is designated by 4. ~his stripping
~:~ means consists of parallel horizontal shafts arranged in a
common plane inclined relative to
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10588~9
the lon,gitudina] dlrection Or the bales, tlhich shafts are hrou,~,hf,
to rotate in a way not shown in detail. The shafts rotate counter-
clockwise. Tools 6, 7 are attached to the shafts, which stri,p the
bale when the ~ale is fed rorwards by striking against fiber
layers and lirting them a~Jay from the bale. The stripping means
is provided wi~h a guide plate 8 on its side turned from the bale,
which plate leads the material broken away from the ba~e down in~o
a store 9 arranged below. A strainer plate 22 ~rith holes Or about
15 mm is arranged between the store 9 and the stripping means 4
` ~ 80 that possible too big bale pieces cannot fall down into the
store but are again pulled along and worked by the tools 6, 7.
The ribers are removed from the store g by a conveyor belt provided
with dogs, the lower edge Or the store serving on one side as a
stripper 11 of the conveyor 10 so that an even discharge Or f;bers
is obtained rrom the store. This conveyor leads to a machine for
l rine defibration of the pulp not shown. The side 1~ opposite to
l~ ~ the,stripper is upwardly directly connected to'the conveyor 3
reeding bales. Moreover the guide plate 8land the store 9 are con-
nected with side plates not shown ror the sake of clearness. In
do the store 9 a level switch 21 is arranged to disconnect the bale
conveyor when the store is rilled in order that damage to the plant
should not occur and to obtain a work-saving, automatic operation
the~machine.
On top Or the bales 1 two guide plates 13 and 14 are arranged,
partly as a protection for the spreading Or the fibers~ partly for
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lOS8819
the tools. These protective plates~ Or which one 14 is plane and
the other 13 is angular, are connccted with a wire 15 via a
pulley 16, so that the angular plate 13, which is pi~oted at its
corner, senses the bale height and adjusts the hei~ht of the
guide plate 14 arranged between guide rolls 17 and 18 so that
this ~qill e~rectively shield the strippin~ means. Posæib'y the
position Or these protective shields can guîde the feed speed of
the conveyor 3 so that~the amount of stripped pulp from the str;pp-
ing means is constant apart from the thicknesses of the bales.
This guiding can e:g. in a way known per se take place by means
thyristors. Along the conveyor 3 the bales can be laterally
guided by means of guide rolls not shown.
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~ The sha~ts rotating counterclockwise are shown more closely in
i, Fig. 2 and 3. The tools 6 and 7 are mounted in pairs on the sharts
5 by means Or rivet joints 19 in an opposite direction rrom the
~ shafts so that the tools 6 and 7 in a tool pai.r at rotation work
f!~ the same groove after each other. The tools are pointed so that
.
V-shaped grooves are obtained in the bale. However, the tool 6 is
more pointed and somewhat longer than the tool 7, which results
20. in the groove profile shown in Fig. 4. Moreover the tools 6 and 7
are arranged alternately along the shafts 5 so that the broader
tools 7 will achieve the aforesaid a].ternate strokes on the backs
~ between the grooves with accompanying loose breaking Or ribers,
; ~ as is:shown to the lert in Fig. 4.
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iO58B19
In Fig. 5 it is rinall~ sho~n ho~r stops are arranged bet~le~n the
sharts provided with tools in the form Or angu]ar irons 23 so
that too ~-ig pieces cannot b~ broken away. ~his stopping effect
can also be achieved by a synchronization in accordance with Fig. 1
of the different shafts 5 so that the tools on the closest shart
serves as a stop. This can a]so result in a more even load on the
drive motor of the stripping means. If it is desired to reduce
the dry content, a pipe 24 for supply of vapour or water to the
pulp and provided with holes for spreading is arranged in at
o least the lowermost of these angular irons or elsewhere.
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In order to obtain such an even feed;ng as possible from the store
to the finishing means for fine defibration and consequéntly to
the final product the stripping means 4 and the conveyor 3 are
dimensioned for a greater capacity than what is other~ise re-
quired so that there is always enough material in the store, in
which the level switch 21 is arranged to disconnect the conveyor 3
when the store is filled.
According to the inventive idea it is essential that the tools
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have no cutting edges which might bring cutting of the fibers. As
~o is apparent from Fig. 2 they need not be radially directed out of
~ the center point Or the shaft, either, but can be displaced so
that they form a positive or negative angle with the radius of
rotation.
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il058819
Working in accordance with the invention i.a. also takes place
with tools of two different types, 6 and 7. It is the object of
the former tool 6 to make grooves in the surf~ce of the bale
with a suitable width at a suitable distance from each other.
This tool has deep action and is longer than the latter. After
the tool 6 has made a groove, this is widene~ to~Jards the sides
Or the tool 7, which therefore has effect substantially lateral~y.
The tools are arranged systematically on their shafts in a way
, , as is apparent from Fig. 2 and 3. It is apparent from these that
~o the tools are arranged in t~o rows (a and b) ~hich may of course
be more. The tools can also be arranged on e.g. circle sectors.
In each row of tools every other tool is o~ type 6 and the others
of type 7. Arter the working of the surrace of the bale has reach-
ed continuity the sur~ace has obtained the appearance evident frorr,
!
Fig. 4. If the grooves are designated rrom left to right by A, B,
C, D etc. the tools in line a will be in the following grooves at
the same time: the tool a6 in the groove A, the tool a7 in the
groove B, the tool ag in the groove C, the tool a7 in the groove
- ~ D and so on. After the shaft has rotated hal~ a revolution the
o tools are in the folIowing grooves: the tool b7 in the groove A,
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the tool b6 in the ~roove B, the tool b7 in the groove C, the tool
b6 in the groove D and so on. The backs shown in Fig. 4 are ex-
posed to strokes by turns by the tool 7 on both sides o~ the back
sides. The backs are broken due to these alternatin~ strokes on
! the back sides in a way as is evident from Fig. Il. As the tool 6
is narrower than the tool 7 there is expansion space for the move-
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~058819
ments of the backs laterally berore they are completely broken.
~orking in accordance with the invention is in this respect a
brèaking more than a stripping. When breaking the backs the bonds
between the fiber ag~lomerates will break where they are wealest.
In this way a defibration is achieved auite without or with a
minimum Or destroyinG of thè separate flbers.
A considerable part of~the defibration work is also carried out
by the loose material being in rapid motion and exerting a con~
siderable friction agai,nst the surface of the bale and the fibers
~o still adhering thereto. This fiber-to-fiber-rr1ction is maintained
by the tools on the rotating shafts. ~en the riber material has
been made free ~^!ithin the working range Or the lower shaft, the
matel'ial i9 moved by the material Or the tools in their rotation
direction along the surface Or the bale and is thrown straight
up~rards, in the direction Or the tangent, into the tool periphery
Or the overhead shaft, where it is caught and moved again along
the surface Or the bale under friction ~rith still adhering fibers.
' This is repeated until the material is moved do~mwards again by
the upper portion of the guide plate on the opposite side Or the
stripping means (4) and is thro~n downwards towards the strainer
plate, (22) at a great speed. The riber agglomerates, which are still
t~o big to pass through the holes of the strainer plate, are moved
on by the tool tips of the lowermost shaft, passing over the,
surface of the strainer plate at a distance Or about 3 mm and are
exposed to a new treatment at a renewed consecutive ~orking in the
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lOS8819
stripping means (1J).
The process described above for stripping of pulp bales of flake-
dried pulp and the means for this are also very suitable for
stripping of pulp taken up in conventional manner in a belt drier,
i.e. pulp in sheet form. Such a pulp bale is fed into the machine
with horizontal sheets. The horizontal sheets are then exposed
to the same attacks by the tools as described above in respect
of the fiber layers in flake-dried pulp. What differs the t~1o
pulp types from each other in respect of ~orking is that the
o fibers in the sheet pulp (belt-dried pulp) are more or less
oriented as to their direction as distinguished from the fibers
in flake-dried pulp. Therefore the sheet pulp will be much tougher
and rnore difficult to strip. A consequence thereof is that the
breaking erfect described above will be less, and the bac'~s are
not broken until they have been higher and exposed to a stronger
influence by the tools.
In the embodiment shown on the drawing the tools have been arranged
on a rotating shaft, but the tools can also be arranged consecu-
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tively on one or more chains or belts running around wheels or
20 pulleys. Another modification is to arrange the tools on e.g.eccentrically driven, possibly guide-controlled tool rods "lhich
.
~ give the tools an upward motion when they touch the sur~ace of the
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pulp bale.
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