CA1076558A - Apparatus for moistening with liquid pluverous to granular pourable material - Google Patents
Apparatus for moistening with liquid pluverous to granular pourable materialInfo
- Publication number
- CA1076558A CA1076558A CA276A CA276A CA1076558A CA 1076558 A CA1076558 A CA 1076558A CA 276 A CA276 A CA 276A CA 276 A CA276 A CA 276A CA 1076558 A CA1076558 A CA 1076558A
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- CA
- Canada
- Prior art keywords
- shaft
- head portion
- mixing
- tools
- shank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Processing And Handling Of Plastics And Other Materials For Molding In General (AREA)
Abstract
TITLE OF THE INVENTION:
"APPARATUS FOR MOISTENING WITH LIQUID PULVEROUS TO
GRANULAR POURABLE MATERIAL"
ABSTRACT OF THE DISCLOSURE:
An apparatus for moistening pourable material of from pulverous to granular and/or fibrous character with liquid, for instance wood chips with glue which comprises a drum defining at least one substantially cylindrical chamber having a mixing shaft rotatably arranged therein. This shaft is equipped with at least one mixing tool having a radial shank arranged on the shaft and also having a head portion connected to the shank for immersing into material to be mixed when passing through the chamber near the inner wall of the drum.
Conduit means lead into the drum and have a substantially radial section in the drum for feeding the liquid into the drum for moistening the material to be mixed. The head portion of the mixing tool has a cross section decreasing from the pertaining shank toward the radially outer end of the head portion. The head portion and the shank form with each other an angle of from 100° to 180°, preferably from 130° to 180°. The apparatus is furthermore provided with inlet and outlet means for respectively admitting chip material to be moistened into and discharging moistened chip material from the chamber.
"APPARATUS FOR MOISTENING WITH LIQUID PULVEROUS TO
GRANULAR POURABLE MATERIAL"
ABSTRACT OF THE DISCLOSURE:
An apparatus for moistening pourable material of from pulverous to granular and/or fibrous character with liquid, for instance wood chips with glue which comprises a drum defining at least one substantially cylindrical chamber having a mixing shaft rotatably arranged therein. This shaft is equipped with at least one mixing tool having a radial shank arranged on the shaft and also having a head portion connected to the shank for immersing into material to be mixed when passing through the chamber near the inner wall of the drum.
Conduit means lead into the drum and have a substantially radial section in the drum for feeding the liquid into the drum for moistening the material to be mixed. The head portion of the mixing tool has a cross section decreasing from the pertaining shank toward the radially outer end of the head portion. The head portion and the shank form with each other an angle of from 100° to 180°, preferably from 130° to 180°. The apparatus is furthermore provided with inlet and outlet means for respectively admitting chip material to be moistened into and discharging moistened chip material from the chamber.
Description
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 ~;
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 -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.
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.
- 3 -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 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 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 , ,;
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.
~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-~ ., . ,~
~'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 ~ ............................................................... ..
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- ~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 ` ~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 ,~ .. ~ ':
. .
`` ~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:, / -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 .. . . .
~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 ~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.
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 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 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 , ,;
. . ::
.
~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-~ ., . ,~
~'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 ~ ............................................................... ..
'. : , ' ::
- ~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 ` ~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 ,~ .. ~ ':
. .
`` ~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:, / -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 .. . . .
~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 ~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.
Claims (12)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An apparatus for moistening fluid material of the type ranging from pulverulent to granular or fibrous consistency with a liquid, com-prising a cylindrical chamber, a shaft rotatable in the chamber, conduit means for charging the chamber with fluid material, outlet means for dis-charging 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 portions 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 tapered 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 converging 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 within the head portion.
2. An apparatus as defined in claim 1 wherein the converging surfaces are planar.
3. An apparatus as defined in claim 1 wherein the cross section of the head portion is part circular with the converging surfaces extending tangent to the circular part and towards each other.
4. An apparatus as defined in claim 1 or 2 or 3 wherein the shank and head portions have a wall thickness of 3 to 5 mm., the shank portion is cylindrical and has a radius of approximately 90 mm., and the head portion is 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.
5. An apparatus as defined in claim 1 wherein the mixing tools are 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.
6. An apparatus as defined in claim 5 wherein adjacent mixing tools are angled obliquely towards one another.
7. An apparatus as defined in claim 1 or 2 or 3 wherein the shaft is hollow and includes conduit means for feeding cooling liquid to the mixing tools.
8. An apparatus as defined in claim 1 or 2 or 3 wherein a plurality of mixing tools are 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.
9. An apparatus as defined in claim 1 wherein the said at least one tool is adjustable radially of the shaft towards and away from the wall of the chamber.
10. An apparatus as defined in claim 1 wherein a plurality of mixing tools are arranged on the shaft at radially offset positions with respect to each other, the mixing tools being so arranged that the tips of the head portions are in the same radial plane normal to the axis of the shaft.
11. An apparatus as defined in claim 1 or 2 or 3 wherein fluid inlet means are provided for supplying moistening fluid such as glue to an area within the chamber.
12. An apparatus as defined in claim 1 or 2 or 3 wherein, in cross section, the mixing tool has a shank having parallel front and rear surfaces, the head has convergently tapering front and rear surfaces, and a 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.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA276A CA1076558A (en) | 1977-04-18 | 1977-04-18 | Apparatus for moistening with liquid pluverous to granular pourable material |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA276A CA1076558A (en) | 1977-04-18 | 1977-04-18 | Apparatus for moistening with liquid pluverous to granular pourable material |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1076558A true CA1076558A (en) | 1980-04-29 |
Family
ID=4083813
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA276A Expired CA1076558A (en) | 1977-04-18 | 1977-04-18 | Apparatus for moistening with liquid pluverous to granular pourable material |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1076558A (en) |
-
1977
- 1977-04-18 CA CA276A patent/CA1076558A/en not_active Expired
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