Note: Descriptions are shown in the official language in which they were submitted.
S58
The present invention relates to an apparatus for moistening pour-
able materials of from pulverous to granular and/or fibrous character with
liquid, for instance wood chips with glue and the like.
With heretofore known mixers of the above mentioned type as disclos-
ed for instance in German Offenlegungsschrift 21 13 960, the mixing tools
have a vane or blade shape, while the radially outer portion of the vane or
blade-shaped mixing tools are inclined forwardly when considering the
direction of rotation of the mixing tools. With these heretofore known mix-
ing tools, the shank is offset relative to the head portion of the mixing
tool whereby in cooperation with the head portion inclined forwardly when
considering the direction of rotation, the radially outer head end runs ahead
of the radially inner portion of the mixing tool. Ln view of the blade or
vane shape of the radially outer head portion, however, the material to be
mixed is subjected to considerable mechanical stresses, especially when chips
are involved which are used for the manufacture of pressed chip boards so that
the chips are subjected to considerable squeezing and friction with the result
that the chip structure is frequently destroyed. The destruction of the
material to be mixed, especially of cut chips, results in qualitatively
second rate chip boards because the flat connection of the individual chips
' 20 with a corresponding crumbling of the pieces no longer exists so that the
bending and transverse strength is considerably affected.
The high frictlon between chips and mixing tools which is encounter-
ed with heretofore known devices, results in a too high and undesired heating
up of the chips and of the mixing tools which in turn causes the deposit of
glue on the mixing tools and the inner wall of the mixing chamber whereby
the structure of the chips is affected in an undesired manner. This is true
particularly within the region of the so-called moistening zone of the appara-
tus in which in addition to the mixing tools also liquid supply lines are
arranged. Such liquid supply lines may in the form of liquid feeding tubes
be located on the hollow mixing shaft and may rotate together therewith, or
they may be designed as stationary tubes which from the outside lead through
the cylindrical mixing wall and have their exit openings extend into the ring
- 1 - ~ '
~7~558
of material to be mixed. ~hile with these known mixing devices it is provided
that the mixing tools are adjustable toward the inner wall of the mixing
chamber and/or about their radial longitudinal axis 3 in other words as to theirangle of attack, they are also adjustable in axial direction of the mixer.
However, these known devices are not designed so that in view of their shape
a definite control of the through-put of the material to be mixed for a
uniform and vast build-up of the ring of material and its thickness and/or a
desired through-put speed of the ring of material to be mixed can be obtained
within certain zones of the mixing chamber nor a desired degree of filling and
of the thickness of the ring within individual zones.
The present invention accordingly provides an apparatus for moisten-
ing fluid material of the type ranging from pulverulent to granular or fibrous
consistency with a liquid, comprising a cylindrical chamber, a shaft rotatable
in the chamber, conduit means for charging the chamber with fluid material,
outlet means for discharging material from the chamber, means for supplying
`' the moistening fluid to the chamber, mixing tools secured to the shaft for
effecting a mixing action on fluid material in the chamber, at least one of
the mixing tools comprising a hollow shank portion and head portion, the por-
tions being at an obtuse angle relative to each other of more than 100, the
head portion being longer than the shank portion, the head portion being taper-
ed evenly inwardly from the shank portion to the tip, the tool being adapted
to rotate with the obtuse angle facing the direction of rotation, the area of
the head portion facing the direction of rotation having two mutually converg-
ing surfaces disposed symmetrically to the centre line of the head portion, the
transition between all surfaces of the head being smoothly rounded, and means
for supplying cooling liquid to within the head portion.
Desirably the converging surfaces are planar.
The cross section of the head portion may be part circular, with the
converging surfaces extending tangent to the circular part and towards each
other.
The shank and head portions may desirably have a wall thickness of 3
to 5 mm. The shank portion may be cylindrical and may have a radius of
~;
- 2 -
558
approximately 90 mm. The head portion may be welded onto the shank portion,
the shank portion being threaded along approximately 50 to 70 mm. of its
length for securing it to the shaft.
The mixing tools may be rotatably secured to the shaft to provide
for adjustment of the angles of the head portions relative to a reference
plane normal to the axis of the shaft, and adjacent mixing tools may be angled
obliquely towards one another.
; The shaft is preferably hollow and includes conduit means Eor feed-
ing cooling liquid to the mixing tools.
; 10 A plurality of mixing tools may be provided, at least some of the
mixing tools being arranged at angles relative to a reference plane normal to
the axis of the shaft such that the material is in operation moved by the tools
axially along the chamber from the conduit means for charging the chamber.
The tool or tools may be adjustable radially of ~he shaft towards
and away from the wall of the chamber.
A plurality of mixing tools may be arranged on the shaft at radially
offset positions with respect to each other, the mixing tools then being so
arranged that the tips of the head portions are in the same radial plane nor-
mal to the axis of the shaft.
Fluid inlet means may be provided for supplying moistening fluid,
such as glue, to an area within the chamber.
The mixing tool may have a shank having parallel front and rear sur-
faces when viewed in cross section, the head having convergently tapering '
front and rear surfaces, and the tip has a surface at an angle of ~ 90 from
the rear surface of the shank, the front surface of the head being at an angle
of < 100 to the front surface of the shank, the transitions between all
adjacent surfaces being rounded.
Embodiments of the invention are described in the following specifi-
cation in connection with the accompanying drawings, in which:
Figure 1 is a partial axial section through an apparatus according
to the invention with the supply of liquid from the outside through the cylin-
der mantle and with mixing tools according to the invention.
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7~5~
Figure la represents a section taken along the line Ia-Ia of Figure 1.
Figures 2-4 respectively illustrate different embodiments of a mix-
ing tool.
Figure 5 represents a sec~ion taken along ~he line V-V of Figure 2.
Figure 6 is a section similar to that of Figure 5 but slightly mod-
ified thereover.
Figure 7 is a section taken along the line ~II-VII of Figure 3.
Figure 8 is a section similar to that of Figure 7 but slightly
modified thereover.
Figure 9 is a section taken along the line I~-IX of Figure 4.
Figure 10 is a section similar to that of Figure 9 but slightly modi-
fied thereover.
Figures 11-15 illustrate different possible arrangements and instal-
lation possibilities of the mixing tools in top view, Figures 12-15 showing
the mouth of the liquid feeding pipes.
Figure 16 is a radial section through a mixing chamber and mixing
shaft while three mixing tools designed according to the invention are arrang-
ed in one radial plane.
Figure 17 illustrates a radial section through a mixer with an outer
glue layer while there are provided two mixing tools according to the inven-
~ion which are located opposite to each other and are arranged axially offset
with regard to each other, the mixing shaft and one mixing tool being shown in
section.
Figure 18 represents a preferred dimensioning of a mixing tool accor-
ding to the invention shown in radial section.
Figure 1~ is a top view of the mixing tool of Figure 18.
Referring now to the drawings in detail, the apparatus diagrammatical-
ly illustrated in Figure 1 in a longitudinal section has a cylindrical chamber
1 in which coaxially therewith a hollow shaft 5 rotates. The liquid to be
added to the material to be mixed, for instance glue and/or a coolant for the
tools connected to the hollow shaft is passed through the hollow chamber of
shaft 5. According to the specific embodiment of Figure 1, cooling fluid is
.. - 4 -
1~765~
through the conduit 17 in shaft 5 conveyed to the mixing tools 2 which are
adjustably arranged on said hollow shaft.
The material to be mixed passes through the material inlet 8 in the
direction of the arrow Z, in other words approximately radially with regard
to shaft 5 into the so-called hauling-in or injection zone 11. In this
region at least one hauling-in or injection tool 10 is provided on the shaft.
In the specific embodiment shown, two of such tools 10 are provided. Instead
, of the tool 10, also the tool 2' according to the invention may be provided.
The tools catch the material to be mixed which arrives in a continuous flow in
the direction of the arrow Z, and impart upon said material a component of
movement in the direction of the axis of shaft 5. The material to be mixed -
will thus pass into the region of tools 2' which rotate together with shaft 5;
of said tools 2', three only are illustrated in Figure 1. These ring-forming
tools 2" are intended to further equalize the deviated flow of material so that
said flow or stream will move in a possibly uniformly thick ring of material
along a helical path and along the cylindrical wall 1' of chamber 1 which
flows in the direction toward the moistening zone 12. That zone which is
adjacent the hauling-in zone 11 and in which this ring formation is designated
as merging or ring forming zone 11' is followed by the moistening zone proper.
When with this apparatus, gluing or chips for the chip plate industry is in-
volved, the moistening or liquid adding zone 12 is also briefly designated as
gluing zone 12. The gluing zone 12 is followed by a post mixing zone 13 which
merges with the discharging zone 14 in which the outlet 9 for the material
proper is located.
In the merging zone (ring-forming zone) 11', in the liquid adding
zone 12, and in the post mixing zone 13, as well as if desired in the discharge
zone 14, mixing tools designed in conformity with the invention are arranged in
the manner according to the present invention. With the embodiment of Figure
1, the liquid to be added is introduced from the outside through liquid feed-
ing line 6, 6', 6". These lines or conduits 6, 6', 6", extend through the
cylinder wall 1' of the cylindrical chamber 1 and have their exit openings 6a
directly immersed in the mixing ring 4 of material. The ring 4 of mixing
-- 5 --
765~
ma~erial moves helically along the inside of the wall l'. In Figure l,
there is illustrated a particularly preferred arrangement of the liquid feed-
ing lines 6, 6', 6". With this arrangement, the mentioned conduits 6, 6',6"
are passed from below through the cylinder wall l' so that the liquid passes
at a slight pressure into ring ~ of mixing ma~erial counter to the effect of
~he gravitational forces. Instead of the supply of liquid from the outside
through the cylinder wall in conformity with Figure 1, the invention may also
be realized when feeding the liquid from the inside. According to this
arrangement, liquid adding pipes are fixedly arranged on the rotating mixer
shaft, and the liquid is passed through said liquid adding pipes by centri-
fugal force into the ring of mixing material. Figures 2-~ and 18 and l9 illus-
trate preferred embodiments of the mixing tools 2 according to the invention.
These mixing tools 2 have a shank 2a which is provided with outer thread 7 and
which merges with a head or head portion 2b. The head portion 2b comprises
a continuous decrease of its cross section starting at the shank 2a and ending
in a tip 2c. The head portion 2b forms with the shank 2a an angle of about
from 100 to 180, preferably an angle of from 130 to 180. The mixing tool
according to the invention has a head portion shaped similar to the closed
beak of a bird or has the shape of an inclined extending cone. Preferably,
the tip 2c is rounded off or is blunt. When the tip 2c of the cone-shaped
head portion 2b is blunt, the tip may have the shape of a chisel known in
connection with the processing of wood. It is furthermore advantageous
especially when the tip is truncated, to produce the tip of hard metal while
the tip is directed toward the wall of khe drum.
The mixing tool 2 comprising shank 2a and head 2b is at least within
the region of the tool head, preferably over its entire length, designed hollow
and has a cross sectional shape which reduces the friction on the material.
Accordingly, the head portion is annular, flattened in an oval manner, or tri-
angular in cross section, preferably in the form of an isosceles triangle as
illustrated in the embodiments of Figures 5 - 10,
The mixing tool rotates with the hollow shaft 5 in the immediate
vicinity of the cylindrical wall 1' in the direction of the arrow R while the
- 6 -
tip 2c with the head portion 2b angled off relative to shank 2a runs ahead of
the mixing tool 2 in the mixing ring 4. If the head portion 2b is in con-
formity with Figures 2, 3, 18 and 19 arranged relative to the shaft 2a, and
inclined forwardly in the direction of rotation R, in other words leading, the
transition 3 from shank 2a into head portion 2b ~Figures 3, 3, 18) is unsteady
on the front portion of the mixing tool 2, in other words is angularly design-
ed, whereas the transition 3a on the backside of the mixing tool is steady,
which means rounded.
According to F~gure 5 representing a section along the line V-V of
Figure 2, the head portion, when maintaining a possibly streamlined formation,
haswhenviewing in the direction of rotation R its front side, the so-called
face side V, provided with two working surfaces V' and V" located symmetrical-
ly with regard to the radial central plane M-M.
With the cross sectional shape of the head portion 2 which may be of
triangular configuration CFigure 5), oval configuration ~Figures 6,7), closed
horseshoe configuration ~Figure 8), streamlined or dropline configuration
(Figure 9) or isosceles or equilateral triangular shaped configuration (Figure
10), the face 5 will thus be divided into two inclined face sections V', V"
i` which are located at an angle with regard to each other. These surfaces V',
V" which are located symmetrically with regard to the radial central plane M-M
and at an incline to each other ~with the embodiment of Figures 9, 10 inclined
to each other in the manner of the sides of a saddle), form working surfaces
which when plowing through the chip material impart upon the chlp material a
component of movement corresponding to the inclined position and configuration
of said working surfaces. In view of the fast rotation, the chip material
striking the front surface V of the beak-shaped head portion 2b is by the par-
tial working surfaces V', V" divided in two partial streams with inclined
opposite directions (see embodiments of Figures 5, 6, 7, 8, 9 and 10).
In Figure 19, this division of the flow of chips S is diagrammatical-
ly illustrated by the working surfaces V', V" inclined relative to each other.
- The stream S of chips which strikes the working surface V' is deviated in the
direction of the arrow Sl, whereas the stream S of the chips which hits the
-- 7 --
,
,;
. . ::
.
~655~
working surface V" located on the other side of the plane of symmetry M-M is
deviated in the direction of the arrow S2. With the embodiment of Figure 8,
the oncoming stream of chips is moved by the two partial surfaces V', V'l in
the same direction. This is effected by the front surface V which is located
perpendicular to the central plane M-M.
With the mixing tool 2 according to the invention it is thus poss-
ible by a selected definite configuration of the front surface V and/or the
partial working surfaces V', V" to obtain an aimed flow of the chip material
which aimed flow depends on the type, especially the structure, of the chip
material (cutting chips; fibrous, granular~ pulverous, or the like material).
In particular when gluing chips in the pressed chip board industry
the design according to the invention of the mixing tool can be used for in-
fluencing in a certain definite manner the movement of the chip particles in
the ring of material to be mixed and also for influencing the thickness of the
ring, -the staying time of the chip particles in the ring and also for influenc-
ing the direction of movement of the particles in the ring of material to be
mixed.
Due to the fact that the shank 2a is provided with a sufficiently
long thread ~Figure 18), it is possible to adjust the mixing tool first in its
radial direction depending on the desired distance from the inner wall 1'. In
this connection the mixing tool with its angled off head portion according to
Figures 2, 3, 18 and 19 may be arranged on the mixer shaft 5 precisely sym-
metrically with regard to the radial central plane M-M ~Figures 5 - 10) which
central plane extends precisely symmetrically with regard to the axis of the
mixing tool with the axis pointing in radial direction. In this adjusted
position the mixing tool does not favor a preferred feeding direction so that
the partial flows formed by the working surfaces V', V" do not prefer one cer-
tain feeding direction, either toward the inlet 8 or toward the material outlet
9.
The mixing tool 2 may, however, also be arranged with its head
portion 2b at an angle, in other words at an incline, to the radial central
- plane M-M. When the head portion 2b is inclined in the direction toward the
,. .~ .
~ - 8 -
, ' ' : , ' ' ' '
- ~7~
outlet 9, the material coming from the material inlet and conveyed helically
along the cylinder wall 1' in the form of a ring of material is braked or
slowed down so that the thickness o-f the ring of material can be increased at
such an adjusted position of a plurality of mixing tools. Inversely the feed-
ing in the direction toward the outlet 9 can be accelerated when the conical
head portion 2b of at least one mixing tool is inclined in the direction to-
ward the material inlet 9 since then the working surfaces V' and V" impart upon
the impacting material a component of movement which is greater in this
direction. ,
This adjustment is effected by a simple turning of the mixing tool 2
relative to the shank and by turning the shank portion 2a on the tool holder
means 5a so as to prevent an accidental loosening of the mixing tool 2. In
- this way any desired position of the head portion 2 can be set in a simple
manner.
This easy adjustability is particularly advantageous in connection
with so-called outer glue application as illustrated in Figure l because in
this instance the mixing tools which are in the gluing zone 12 can be so adjust-
ed that they deviate the flow of material directly toward the projecting feed-
ing tubes 6, especially toward the outlet 6a of the feeding tubes 6, 6', 6"
located in the gluing zone and into the space which in the direction of
rotation R is located behind the feeding tubes. As a result thereof a sticking
of glue to the outer walls of the feeding tubes 6 or to the inside of the wall
1' can be avoided. If it is noted that adherence of glue occurs in the region
of the feeding tubes 6 or of the inner wall 1' within the gluing zone 12, the
ring of chip material can be enlarged as to its thickness by inclining the head
portion 2b in the direction toward the outlet 9 so that more chips will flow
around the free ends of the feeding tubes 6, 6', 6" and around the inner wall
in this zone thereby taking along or carrying away any excessive glue which
may get deposited.
; 30 The mixing tools 2 are advantageous, particularly in the region of
the transition zone 11' and in the gluing zone 12, in groups of at least two,
preferably two or four tools uniformly distributed over the circumference of
_ 9
, . . . .
.. . . . . . .
~Ç137G~i8
the shaft in a radial plane. In this instance the mixing tools 2 are in the
gluing zone respectively provided on both sides of the feeding tubes 6, 6',
6" so that the working surfaces V', V" of the mixing tool heads 2b will
deviate a partial flow of material into the direct range of the adjacent
liquid feeding tube. The feeding tubes 6, 6', 6" are thus intensively
acted upon from both sides nearly all around by the flow o-f chips so that
the liquid being discharged will be fully taken up by the material and due
to the high kinetic energy of movement and the intensive intermixing in
this zone inherent thereto will be spread to the individual chips by rubbing
;~ 10 of the chips against each other and will thus be uniformly distributed.
Inasmuch as with the mixing tool according to the invention the
~ shank 2a has a relatively large diameter relative to the conical head
i portion 2b, the chip material will be displaced radially upwardly by the
shank 2a which projects radially from the shaft, this displacement occurs
in particular in the transition zone 11' (ring forming zone) between the
inlet zone 11 and the gluing zone 12 in which the flow of chips has not yet
formed a nearly uniform ring of material of even thickness. As a result of
this displacement, the formation of a ring of chip material in the region
of the dTum mantle is aided because during the fast rotation the chips are
~` 20 displaced from the inner space of the mixing container by the relatively
strong shank portions 2a toward the inner wall 1' of the drum. The head
;~ portion 2b which ends conically in the direction of the rounded or truncat-
ed tip 2c extends in a gentle manner and thereby without destroying the
structure of the chips into the material to be mixed, which is under the
influence of the centrifugal force, plows through the material and exerts
upon the same, depending on its respective adjusted position, an action
which is neutral in its direction of feeding, or a braking action or an
accelerating action in the direction toward the outlet. The magnitude of
the inclination of the head portion 2b has a direct influence upon the
degree of compacting of the chip material. The more the heads 2b are in-
clined forwardly in the direction of rotation R, the more they will lift
the chip material off the mantle 1' of the drum and the less the chips
;
, - 10 -
~7655~3
or another material will be compacted in the ring 4 o material moving
toward the outlet 9. If the angle of inclination of the heads 2b relative
to the shank is only slight or zero, as is the case with the embodiment of
Figure 4, the chip material will be compacted to a greater degree within
the ring 4. The greatest compacting of the chip material will thus be
effected when the angle between shank and head portion amounts to about 180
as shown in Pigure 4.
Particularly advantageous are tool heads 2b with an inclination
in the direction of rotation R, for instance, with an inclination of from
135 to 165 because with such an inclination the easily breakable chips
are the least compacted and thus will be mechanically stressed the least
and consequently their structure will su-ffer the least damage, while there
exist the desired good feeding and the desired sufficient friction of chip
particles against each other. Such tools will furthermore not cause any
squeezing when the tools with their head portion 2b rotate at high speed
between adjacent glue feeding tubes 6, 6', and 6', 6". The increase in the
cross section of the head portlon in the direction toward the shank 2a
further brings about that with each rotation of the tool 2 greater quantities
of chips are pushed through between each two adjacent glue feeding tubes 6,
6' and 6`, 6". These chips pushed through between two tubes 6, 6' are in
the space between the container wall and the outlet 6a of the tubes by the
rotating tips 2c of the heads 2b displaced in the direction of rotation
approximately parallel to the glue feeding tubes 6, 6', 6'1 when the heads
2b are strongly inclined in the direction of rotation. This displacement of
the chips in radial direction prevents the freshly picked up glue drops
from being deposited to any major extent on the inner wall 1' and from settl-
ing thereon together with dust. The tools according to the invention thus
permit, in particular in the gluing zone, so to control the movement of the
flow of chips that the axial movement of the chips is reduced to a minim~
which axial movement favors the giving off of glue from the freshly moistened
chip particles on the inner cylinder wall 1'. The tools according to the
invention also assure that a proper relationship exists between the dis-
~ ., . ,~
- 11 -
~'7~5~3
charged quantity of glue and the quantity of chips in this zone so that if
too much glue is discharged, a depositing of the glue on the feeding tubes
and/or the wall l' will not occur.
In the so~called transition zone 11' (ring forming zone) between
the inlet 8 and the first liquid feeding tube 6" of the gluing zone the
utilization of the mixing tools 2 according to the invention is particularly
advantageous.
With the heretofore known devices the vane-like or blade-like
hauling-in tools 10 throw the material to be mixed primarily in axial
cdirection which means in the direction toward the outlet 9 of the machine
and at the same time radially outwardly, and this is a result of the
asymmetrical design of the tools 10. Such tools are simultaneously in a
worm-like manner distributed over the circumference of the shaft 5 to
generate a correspondingly high axial thrust of the chips which is necessary
for a desired throughput in the device. Ring forming tools which follow the
hauling-in tools 10 are in principal designed similar to the hauling-in
tools, which means, are likewise vane or blade-shaped. These ring forming
tools are intended to accelerate the ring formation. The afore mentioned
~ools bring about that the material to be mixed passes from the inlet zone
11 through the ring forming zone 11' helically and under great axial pres-
sure into the gluing zone 12. This helical action of the material to be
mixed has the drawback that the~material in the gluing zone is not yet
formed into a stable, uniformly moved and uniformly thick ring. In view of
the non-uniform piling up of the chip material, the glue given off in the ~-
gluing zone can always again reach the inner wall 1' and can deposit thereon.
Due to the symmetrical design and the uniform displacement of
the material ~o be mixed toward both sides in view of a corresponding
symmetrical adjustment of the tools 2 according to the invention, and when
arranging a plurality of such tools in a radial plane, especially directly
past the houling-in or throwing-in tools 10 in the so-called ring forming
zone 11', it is possible in this ring forming zone 11' to dissolve the on-
coming non-uniformly piled up and non-uniformly distributed material to be
~ ............................................................... ..
- 12 -
'. : , ' ::
- ~765~3
mixed in a short axial path in circumferential direction and to evenly
distribute the same. This is effected by a plurality of tools 2 according
to the invention preferably distributed in a radial plane over the shaft 5.
In this connection, in conformity with the illustration of Figure 12, the
heads 2b are adjusted symmetrically to the central plane M-M which means
without favoring one certain direction. Since with this arrangement no
preferred conveying effect occurs, the material is by means of the heads
2b and the relatively strongly working shanks 2a conveyed merely radially
outwardly and dissolved in circumferential direction and distributed uniform-
10 ly.
As a result thereof the degree of filling and thus the ring ofmaterial to be mixed 4 can while still ahead of the gluing zone and directly
, at the beginning of the cylindrical mixing chamber 1 proper be built up
uniformly and can be stabilized. With such an arrangement of the tools 2
in groups and in a position not favoring any specific feeding direction
directly ahead of the gluing tools and following the vane-like hauling-in
tools 10, the sticking of the glue, which with all heretofore known devices
has been put up with, will be avoided in conformity with the present invent-
ion in the region of the inner wall o the gluing zone. By a corresponding
inclination of the heads 2b, depending on the respective structural condit-
ions o the material to be mixed (coarser or finer flat chips, through-
put, specific weight of the material to be mixed, etc), a correction can be
effected without difficulties. To this end, it is merely necessary, to
create a stable ring of material to be mixed, to effect the inclination of
the heads 2b of the mixing tools 2 either in the direction toward the inlet
8 or in opposite direction in conformity with the desired formation of a
stable ring of material. In this way it is possible to assure that no mix-
ing material will collect in the region o-f the hauling-in zone 11 and that
over the entire length of the machine up to the outlet 14 a uniformly high
degree of filling will prevail.
It is also possible without difficulties, instead of providing
a group of mixing tools according to the invention in a radial plane, to
- 13 -
` ~7~SSi~
provide two of such groups in series which will together be effective ln the
so-called transition zone 11' (ring forming zone~.
In view of the design according to the invention, also the destruc-
tion of the chips is greatly reduced. Such destruction occurs in particular
ahead of the gluing zone proper because at that time the chips have not yet
acquired the moisture inherent to the gluing operation and thus have not yet
acquired a better elasticity. Since due to the conical design of the tool
heads in conformity with the invention these tool heads grasp the chips par-
ticularly gently, the destruction of the chip structure, especially in the
transition zone, is extremely low when the tool heads are plowing through the
chips. As mentioned above, the forwardly directed conical head portions 2b
act counter to the centrifugal force which acts upon the chips so that the
chips, in contrast to the action of heretofore known devices, are not strongly
compressed on the drum wall and are not thrown against the latter. This is
of particular importance in the gluing zone 12 hecause the glue is up to
fifteen times heavier than the chip material. The chip particles covered
with glue are thus immediately centrifuged outwardly if no uniform dense
stable ring of mixing material exists in the gluing zone 12, and the centri-
fuged out chips give off the glue to the inner wall 1' so that the danger of
deposit of glue is particularly great when the rings- of material to be mixed
are not sufficiently uniform or not sufficiently stab~le.
Figures 11-15 and 16 and 17 represent different adjusting possi-
bilities for the tools. In Figure 11, four tools are arranged uniformly in a
radial plane on shaft 5. The tools rotate in the direction of the arrow R. ~
The head portion 2b of the tools 2 arranged diametrically opposite to each -
other is inclined in the direction toward the left. It thus exerts an
impeding or braking effect upon the chip passage U. If necessary, directly
adjacent the group of tools 2 arranged in a radial plane, one or more tools
may be provided the head portion 2 of which occupies a position which does
not favor any feeding direction over the other. -
Figure 12 shows an arrangement of two tools with shank section
,~ .. ~ ':
- 14 -
. .
`` ~87~55~ii
2a and head section 2b, according to which the tools are offset relative to
each other by 180. The head section 2b with its conical ~ip does not favor
one feeding direction over the other, in other words, is arranged precisely
along the radial central plane M-M.
With the tool position shown in Figure 13, the head 2b of the
upper tool is adjusted against the direction U of the passage of material,
whereas the head 2b of the diametrically oppositely located lower tool is
directed in the direction U. By a simple turning of the foot section 2a in
its fittinglon shaft 5, the head portion can be moved into the opposite
direction as indicated by dot-dash lines so that a desired individual adjust-
ment will be possible without difficulties and at any time in conformity with
the prevailing conditions.
Figure 1~ shows the various adjusting possibilities, namely the
position in which the tool does not favor one direction over the other~ the
position toward the direction U of the passage of material, in the direction
in which the tool exerts a retarding effect upon the feeding flow of the
material, and in the direction M in which the tool accelerates the feeding
flow.
In one radial plane, the tools may occupy either the same
position or over the circumference may alternately when providing two tools
be adjusted so as to have the head portion 2b pointing in opposite directions
so that two diametrically located tools with this adjustment will together
as a group not favor one feeding direction over another feeding direction.
When providing three tools in a group, an adjustment of the three tools is
possible according to which the head portions 2b or two offset tools are
directed in opposite directions while the head portion of the third tool
is located symmetrically in the radial central plane so that as a total the
three-tool group will by itself not favor one feeding direction over another
feeding direction. Such an arrangement is diagrammatically indicated in
Figure 15. According to Figure 15, a special arrangement of a three-tool
group is provided with the tools being mounted in axially spaced arrangement
to each other on shaft 5. That tool of said three-tool group which is
:h, r:, / -
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1~7~5~ii8
connected to the shat and located on the right hand side thereof (with
regard to the drawing) has the head portion 2b adjusted toward the direction
U, in otheT words toward the left so ~hat this head portion acts upon the
material to be mixed so as to impede the flow of the material, in other
words the head portion 2b is directed in a direction opposite to the direct-
ion U. In the central portion of said last mentioned group, there is
provided a second tool according to the invention. With this tool, the head
portion 2b is so adjusted as not to favor one feeding direction over ano~her
feeding direction. The tool of said last mentioned three-tool group which
is shown in the drawing on the left hand side of said group has its head
portion 2b adjusted in the direction U which means toward the right so that
this head portion 2b accelerates the material to be mixed in the direction U.
The embodiment of Figures 11-15 thus shows that each association
precisely adaptable to the corresponding individual condition and that each
adjustment of the individual tools and thus the realization of a certain
effect upon the conveyed material to be mixed and to be moistened is possible.
The embodiment illustrated in Figure 16 comprises three tools
with shanks 2a which are adjustably connected to shaft 5. The tool heads 2b ~ -
have their rounded tips 2c so arranged as not to favor any feeding direction
over the other and move in the direction of the arrow R. A second axially
offset group of mixing tools according to the invention is indicated in
Figure 16 by dot-dash lines.
Figure 17 illustrates two mixing tools with shanks 2a which are
located diametrically opposite to each other and are adjustably arranged on
shaft 5. The liquid feeding pipe 6 passes through the cylinder wall 1'
while the outlet 6a of said pipe 6 is located within the sphere of operation
of one of the two working surfaces of the head portion 2b so that the -~
material to be mixed continuously flows ~ound the outlet opening 6a or
the liquid pipe 6.
Figure 18 shows a tool according to the invention on a scale 1~
It has been found that for mixing devices with a drum diameter of 400mm, a
mixing tool of a total length of about 150mm has proved particularly
.. . . .
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~lt76~8
adyantageous. The shank 2a is provided with an outer thread 7. This shank
is to be screwed into a sleeve (not shown) provided at the lower end of the
hollow shaft 5. The working surface, in other words the front side V of
head 2b, is inc].ined relative to the tubular tool shank 2a by from 100 to
180 , preferably between 135 and 165 in the direction of rotation R.
The end 2c of this head portion 2b is either truncated or
roun~ed off. In the specific embodiment shown in Figure 1~, the head portion
2b resembles a fingertip. The cross sectional surface is within the region
of the backside H of the head portion approximately semicircular, and in the
region of the front section V of the head portion is provided with two work-
ing surfaces Vl and V2 arranged to each other in the manner of the sides of
a saddle. These two working surfaces deflect the flow or current of chips
in the above mentioned manner toward two different sides. The overall tool
is tubular while the beak-shaped head portion 2b is welded to the tubular
shank portion 2a and both parts have about the same wall thickness. The
fingertip shaped tip preferably has one single radius.
Inasmuch as the tool 2 is hollow throughout, it is possible in a
particularly simple manner to obtain a complete and un1form cooling of the
tool. To this end, it is advantageous to introduce into the tool (Figures
2-4) a for instance flexible hose 27 along the central axis of the tool and
parallel thereto. By means of a pipe section 16, the hose may communicate
with the inner pipe 17 conveying the cooling water. According to the em- ~ :
bodiment of Figure 4, a pipe 16 conveying the cooling liquid is in the form
of a rigid pipe inserted into the mixing tool 2.
In view of the flexible structure of the hose 27, the cooling
fluid can be conveyed into the outermost tip 2c of the head portion 2 with
a corresponding curvature of the hose.
As mentioned above, the tools according to the invention are,
due to their inclination in the direction of rotation and in view of their
conical round cross section shape parti~ularly gentle for easily breakable
chips. The tools according to the invention are particularly suitable,
therefore, for installation in the transition zone 11' and in the gluing
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~97f~5~8
zone 12 where during their rotation with their tips 2c between the station-
ary glue inlet pipes 6l etc., extending into the interior of the drum, they
do not exert any shearing effect upon the pipes 6. With each rotation of
said tools, the tools move the chips from the drum wall radially inwardly
and more specifically about parallel to the liquid feeding pipe 6, in other
words opposite to the centrifugal effect. In this way, not only the tendency
of giving off glue onto the inner wall 1' is reduced, but also a loosening
up and an equalization of the chip flow against the centrifuging and thus
separating effect of the chips will be obtained which chips differ from each
other as to weight. The tools according to the invention can with the same
advantage also be arranged in the post mixing zone 13.
Similarly, the outlet zone 14 is likewise provided with such
tools and with a correspondingly designed inclination of the head portions
2b.
The tool according to the invention can thus be employed in all
zones of the cylindrical mix1ng chamber so that a device can be equipped
with only one type of tools. This equipment with only one single type of
tools is not only relatively inexpensive and simple to repair because only
one type of replacement tool for the mixing tools is necessary, but there
additiqnally exists the advantage that in view of the adjustability accord-
ing to the invention of this single tool type, precisely defined effects can
be exerted upon the material to be mixed. To this end, it is merely
necessary to turn the tool head 2b into a desired position of inclination
with regard to the radial plane extending through the connecting area and -
the radial axis of the tool. In this way, all tools provided in a mixer in
the individual zones, in other words in the ring forming zone 11', the gluing
zone 12, the post mixing zone 13, and the outlet zone 14 can be set in con-
formity with totally different technical effects.
It is, of course, to be understood that the present invention is,
by no means, limited to the specific showing in the drawings, but also com- -
prises any modifications within the scope of the appended claims.
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