EP1216803B1 - Equalizing roll - Google Patents

Description

The invention relates to a leveling roller and a method for equalizing a scattered on a conveyor belt layer of free-flowing goods according to the preamble of claims 1 and 11.

For the production of building boards pourable bulk materials such as wood chips, wood chips (strands), wood fibers, straw chips or shredded paper with the addition of binders are sprinkled onto a transport or forming tape to form a nonwoven, to then be pressed into sheets. In order to ensure a consistent high quality of the plates, it is necessary that the scattered fleece as possible over the entire length and width has a uniform predetermined height of scatter on the transport and forming belts. In particular, in the production of wood fiber boards (MDF) a nonwoven fabric with layer thicknesses of about 20 to 200 cm is scattered on the forming belt in order to press plate thicknesses of 4 to 40 mm. In order to comply as precisely as possible with these predetermined spreading heights, it is common to use leveling rolls which comb out the excess scattering height or the irregularities.

Such Egalisierungswalze is ready from the Deppe / Ernst, paperback the chipboard technology, 3rd edition 1991, page 191 previously known. There, a spreading station for MDF boards is shown, in which wood fibers glued on a metering bunker are continuously fed onto spreading rollers. By the scattering rollers, the fibers are sprinkled onto a continuously conveying forming belt, which is the nonwoven fabric of a Plate press feeds. Since such a fiber fleece can have height differences of up to 10 cm on its surface, which lead to density differences in the finished panels, a height-adjustable leveling roller is provided at the end of the scattering station. This leveling roller consists of a cylindrical roller body, on the lateral surface of a plurality of vertically projecting spines are arranged, which comb the excess fiber height, which is then sucked above the leveling roller. However, such spiked rollers have the disadvantage that counteracting the conveying direction against the conveying direction only immediately linear before the spines existing hump-shaped irregularities and depressions are compensated, with lateral depressions are usually not compensated by the existing in front of the spines humps hump. Moreover, leave the relatively long spikes in the uncoated nonwoven fabric in the conveying direction extending parallel grooves through which a residual ripple remains in the nonwoven fabric.

From EP 0 794 854 B1 an apparatus for leveling a wood fiber fleece is known, which comprises a rotation roller on which a plurality of inclined elliptical disks are arranged side by side. In this case, the discs are inclined at an angle of about 60 °, thereby describing a circular path when rotated relative to the nonwoven fabric. The fiber particles are thereby transported continuously on the material web transversely to the conveying direction, so that there is also a transverse distribution of the excess fiber bumps. However, since all the elliptical disks are arranged partially next to each other and aligned in the same inclination, transport all discs in the same transverse direction with the same depth of penetration, so that when using such a leveling roll on the nonwoven at least at low rotational speed results in a sinusoidal serpentine pattern still has a residual ripple. Such a thing Structural pattern should be avoidable but only by several successive leveling rollers with different penetration depths and different initial roll positions, but this requires a high equipment-related effort. Even if the elliptical disks are arranged individually or in groups in different positions relative to the rotational position of the shaft, a fiber fleece results at least even at a low rotational speed, which does not automatically compensate for any unevenness and still have a residual waviness.

A device for smoothing the surfaces of current set sheets of material such as wood fiber, wood or plastic is known from DE-C1-199 09 967.

The invention is therefore an object of the invention to improve a so-called equalization and thus carried out process so that even at relatively low peripheral velocities a largely flat surface structure of a scattered web of free-flowing bulk materials can be achieved and this with the simplest structural design.

This object is achieved by the invention specified in the claims 1 and 11. Further developments and advantageous embodiments of the invention are specified in the dependent claims.

The invention has the advantage, at least in the case of a radial phase offset of approximately 120 ° of the adjacent annular disks, of continuously opposing lateral movement and penetration, the effects of which, as in the case of the three-phase phase shift on the entire surface, automatically lead to a constant homogenizing effect even at low rotational speeds.

Due to the inclined circular discs results in a continuously changing penetration depth, which depends on the angular position of the toothed disc for each disc Rotary position of the roller depends. Advantageously, this results in an average penetration depth, which is constant, at least at an angular offset of approximately 120 ° of the adjacent ring gear discs, so that even in the vertical direction a uniform milling and compensation of the excess web surface takes place. As a result, even with just one leveling roller advantageously a very accurate and uniform spreading height can be achieved, which leads to high-quality building boards, the surface of which usually requires hardly any further processing.

The invention also has the advantage that a constant in the sum of the adjacent discontinuous transverse and depth movement is achievable at least at an approximate angular offset of 120 ° of the adjacent annular disks, so that a uniform leveling is basically reachable even at a peripheral speed of the leveling roller, which corresponds to the conveying speed of the transport or forming belt, without any residual ripple remaining on the nonwoven surface. As a result, a throw of excess fiber material on the leveling roller is largely prevented at the same time, so that an extraction or a series connection of several leveling rollers is unnecessary. At the same time excessive wear is prevented at a low peripheral speed of the leveling roller, resulting in a long life of such a wearing part. In particular, such a low rotational speed leads to an economical use of such leveling rollers, which then require only low drive power and are inexpensive to produce because of low material loads.

Fig. 1:

einen Ausschnitt einer Streustation mit einer Egalisierungswalze in Seitenansicht, und

Fig. 2:

eine Egalisierungswalze in Vorderansicht.

The invention will be explained in more detail with reference to an embodiment which is illustrated in the drawing. Show it:

Fig. 1:

a section of a scattering station with a leveling roller in side view, and

Fig. 2:

a leveling roller in front view.

In Fig. 1 of the drawing, a scattering station for fiberboard is shown, which contains a leveling roller 1 with inclined and inclined annular disks 2 for leveling a scattered fiber web 3.

In the production of sheets of free-flowing bulk solids such as wood fibers provided with binders 4 glued wood fibers are sprinkled onto a transport or forming belt 5 to a fiber web 3 in a scattering station from a metering bunker. The wood fibers are distributed as evenly as possible by spreading rollers on a transport or forming belt 5 in order to produce homogeneous fiberboard can. Since fleece heights of up to 2 m in height and web widths of up to 5 m in width are scattered, in particular when spreading wood fibers, it is usually unavoidable that the nonwoven surface has a residual waviness 6 with height differences of up to 10 cm both in the longitudinal and in the transverse direction ,
These height differences lead after compression to density variations and uneven plate surfaces, which are undesirable. Therefore, a leveling roller 1 is provided at the output of the scattering station above the forming belt 5, which should compensate for this residual ripple 6 and other differences in height.
The leveling roller 1 is height-adjustable and connected to a drive which causes the leveling roller 1 to rotate at a constant speed as a function of the forming belt speed. In this case, rotational speeds of 10 to 1,000 U / min at conventional molding belt speeds are usually sufficient. Below the rotating leveling roller 1, the nonwoven fabric 3 counter to the rotational direction of the roller 1 with constant conveying speed V to the plate press or conveyed in multilayer plates to another scattering station.

The leveling roller 1 consists of a cylindrical roller body 7 of a uniform diameter on which a plurality of adjacent ring disks 2 are arranged. This roller body 7 preferably has a diameter of 400 mm, but can also be made in diameter sizes of 200 to 800 mm. The roller 1 is equipped with a central drive shaft or laterally mounted bearing journals 8, which serve for storage and for driving. The bearing pin 8 or the drive shaft is suspended above adjustable height on a stationary device part 9, so that an adaptation to different spreading heights is adjustable.

The discs 2 are annular and carry on their periphery a plurality of elevations 10, which are preferably tooth-shaped and through which the wood fiber material is taken against the transport direction. Preferably, these annular discs 2 are made as thin sheet metal rings in widths of 1 to 5 mm and have an outer diameter of about 500 mm, with a tooth height of about 50 mm is provided. On the ring gear disc 2, a plurality of small or a smaller number of larger teeth can be provided depending on the predetermined speed and the intended number of juxtaposed discs 2. Preferably, ring plates 2 having 8 to 24 teeth have proven useful in practice, which are slightly acute-angled against the direction of rotation 11 and thus largely prevent a throw-over of the fiber material onto the uncoated nonwoven surface. For a level surface compensation, the peripheral speed of the leveling roller 1 should correspond at least to the conveying speed V on the forming or conveyor belt.

The leveling effect of the roller 1 provided according to the invention is generated primarily by an overlapping movement range of the adjacent annular disks 2, in which the resulting direction of movement of each adjacent disk 2 changes continuously during the rotation. The formation of the leveling roller 1 in particular by the arrangement of the toothed ring disks 2 is shown in Fig. 2 of the drawing. The same reference numerals are used for the functionally identical parts as in Fig. 1 of the drawing.

The ring gears 2 are formed as a flat plane stamped sheet metal rings, which are pushed onto the cylindrical roller body 7. In this case, about 30 toothed ring discs per meter roller length are provided side by side. On the roller body 7 three guide grooves are provided at a radial distance 12 of 120 °, in which the fastening lugs 14 are pushed onto the annular disks 2. In this case, the individual toothed ring disks 2 are arranged obliquely inclined relative to an orthogonal to the axis of rotation 15. Advantageously, an initial slope of the first toothed ring disc 2 is provided to the orthogonal of the axis of rotation 15 of about 5 °, which causes a lateral wobbling motion of the disc of about 40 mm with a pulley diameter of 500 mm during rotation. Since each individual toothed ring disc rotates synchronously with the rotating shaft 8, a tumbling motion results in which the disc 2 in the area of the contact surface with the fiber fleece 3 performs a continuous oscillating transverse movement and a vertical movement of the same type. This results in a continuous change in the resulting direction of movement, which not only remove the fibers from the respective toothed disk 2 forward but also transversely to the conveying direction of the surface and thus compensate existing depressions and clumps in the longitudinal and transverse directions.

However, the particularly smoothing effect only results from the particular arrangement of a plurality of adjacent disks 2, which bring about an advantageous addition of the overlapping individual movements. Thus, the patch next to the starting disc 2 second annular disc 16 is positioned in the same inclination angle position to the orthogonal of the axis of rotation 15 on the roller body 7, but with a radial angular offset 12 of 120 ° and so spaced from the first disc 2, that overlap the transverse movement areas partially. This results in the smallest axial distance of the discs 2, 16 from each other an arrangement in which the two toothed discs touch at its closest point and the largest distance provided a distance from each other, in which only overlap the transverse movement areas at least slightly.

In addition to this second ring disc 16, a similar third ring disc 17 is again arranged, which likewise has the same oblique inclination to the orthogonal as the first ring disc 2. However, the third ring disc 17 is again offset by a radial angle 12 of 120 ° relative to the second ring disc 16. Since all three annular discs 2, 16, 17 are radially offset by 120 ° to each other, results in favorable lateral placement on which the adjacent discs 2, 16, 17 touch or have only a small distance from each other at this narrowest point, an overlap region of Since each rotating annular disc 2, 16, 17 describes a sinusoidal serpentine line on the continuously conveying forming belt 5, the three gearwheel disks 2, 16, 17 radially offset by 120 ° produce a constant resulting effect on the Fleece surface, so that even at low shaft speed almost no residual ripple remains on the nonwoven surface. This effect occurs not only in the lateral overlap area, but advantageously also in the vertical overlap region, so that even by simple circular washers 2, 16, 17 a constant Egalisierungshöhe can be reached, although the individual discs 2, 16, 17 describe a height variation on the circumferential path relative to the nonwoven surface during rotation.

Even with the continuation of the similar arrangement of the ring gears 2, 16, 17 on the roller body 7 by an angular offset 12 of 120 °, the fourth ring gear 18 has the same radial orientation as the first ring 2. This radial position repeats basically after all three disc arrangements , So that all adjoining ring gear discs 2, 16, 17, 18 have an overlap area against each other, which adds so additively with the turn adjacent, that a nearly flat surface structure can be reached, which compensates to a particular extent, lateral bumps and the excess fibers after all Directions distributed in front of the leveling roller 1. In particular, the radial angular offset 12 of 120 ° has been found to be optimal, since in this case all adjacent components of movement complement each other to a constant resultant and thus a sufficiently flat web surface can already be achieved with a single low-speed leveling roller 1. As it is a rapid wear of the toothed discs and a premature throwing of the removed wood fibers is avoided on the leveled nonwoven surface.

There are also other radial misalignment angle of the adjacent discs 2, 16, 17, 18 in an angular range of 90 ° to 150 ° executable that produce relatively flat fleece surfaces at higher rotational speeds. The inventive effect occurs no later than at offset angles of 180 °, since here arise areas on the nonwoven fabric, which overlap neither in the oscillating transverse movement nor in the oscillating height movement, so that these at least at low Rotation speed can hardly avoid a ripple.

However, the inventive effect of Egalisierungswalze also with other initial inclination angles to the orthogonal of the axis of rotation 15 can be achieved. For larger angles of inclination, in any case, larger axial distances between the adjacent ring gears 2, 16, 17, 18, whereby the inventive leveling effect requires a higher speed difference between the rotational speed and the conveying speed V in order to achieve the additive effect as constant. For smaller initial inclinations of the ring gear 2, the overlap region in the transverse or axial direction is relatively low, so that in practice a slower transverse distribution has been found.

The advantageous radial angle offset arrangement of the inclined ring gear disks 2, 16, 17, 18 can be produced in a simple manner by means of different spacer sleeves between the adjacent annular disks 2, 16, 17, 18. Thus, the ring gear disks 2, 16, 17, 18 are fixed axially by threaded rods 19 inserted in the guide grooves. The threaded rods 19 are inserted through the existing eyelets in the rings 14, wherein spacer sleeves are arranged between the adjacent eyelets. In the proposed leveling roller 1, 18 spacer sleeves of 20, 30 and 40 mm in length are arranged between the adjacent ring gears 2, 16, 17, so that there is a sufficiently large lateral overlap area and the adjacent annular discs 2, 16, 17, 18 at their densest point still have a distance of a few millimeters, in order to prevent there jamming of the fibers. In the next adjacent ring gear disc 2, 16, 17, 18, the same sleeve lengths are used, but radially offset by an angle of 120 ° between the discs 2, 16, 17, 18 are arranged. This will be the same with everyone further adjacent toothed ring discs 2, 16, 17, 18 made so that always sets the intended radially offset positioning at the same inclination angle to the orthogonal axis of rotation 15. At the roll ends, the threaded rods are provided with nuts and tightened against each other, so that the ring gears 2, 16, 17, 18 are fixed against each other and on the roller body 7 and represent the leveling roller 1 according to the invention.

Such a ring gear disc 2, 16, 17, 18 but could also be secured by a permanent weld on the roller body 7. The annular discs 2, 16, 17, 18 need not be formed as a continuous annular surfaces, but may also have gaps or interruptions at regular or irregular intervals. The annular discs 2, 16, 17, 18 may also be arranged on the roller body 7 so that only a dense sequence of elevations, teeth 10 or spikes protrudes from the roller surface. It is also conceivable that the toothed ring arrangement is machined directly from a base body or produced by means of a mold. Such a leveling roller 1 can be used not only to equalize a nonwoven fabric, but also in all other scattered nonwovens from free-flowing goods.

Claims (11)

1. Equalizing roller for homogenizing layers (3) of pourable goods spread onto a conveyor belt (5), in particular layers of glued wood fibres, comprising a rotatable, cylindrical roller (7), on which an array of inclined ring discs (2, 16, 17, 18), arranged axially one beside the other, which carry out an overlapping wobbling movement when in rotation, is arranged, characterised in that said ring discs (2, 16, 17, 18) are designed as round, circular elements, and in that adjacent, inclined ring discs (2, 16, 17, 18) are tangentially offset from each other (12) by an angle of 90 to 150°.
2. Equalizing roller according to claim 1, characterised in that the ring discs (2, 16, 17, 18) consist of a sheet steel ring which is either continuous or has interruptions or gaps, and which is mounted onto or attached to a roller (7).
3. Equalizing roller according to claim 1 or 2, characterised in that on the outer circumference of the ring discs (2, 16, 17, 18), raised parts, in particular teeth (10) or spikes, are provided.
4. Equalizing roller according to one of the preceding claims, characterised in that the ring discs (2, 16, 17, 18) are designed as flat, undulated or structured sheet steel discs and are arranged at or on the circumference of the roller.
5. Equalizing roller according to one of the preceding claims, characterised in that the ring discs (2, 16, 17, 18) are arranged on the roller (7) in such a way that they form an angle of inclination of 3 to 30° with respect to an orthogonal to the axis of rotation (15).
6. Equalizing roller according to one of the preceding claims, characterised in that adjacent ring discs (2, 16, 17, 18) are arranged at a 120° tangential offset from each other.
7. Equalizing roller according to one of the preceding claims, characterised in that the ring surface or the raised parts (10) protrude from the circumferential surface of the roller (7), in particular in a range between 30 and 130 mm.
8. Equalizing roller according to one of the preceding claims, characterised in that the raised parts are designed as teeth (10) or spikes protruding from the circumference of the ring surface at a distance of 10 to 100 mm and forming toothed (2, 16, 17, 18) or spiked ring discs.
9. Equalizing roller according to one of the preceding claims, characterised in that the minimum axial distances of adjacent ring discs (2, 16, 17, 18) are such that the ring discs contact each other in the closest point and the maximum axial distances are such that the wobbling areas still overlap.
10. Equalizing roller according to one of the preceding claims, characterised in that the ring discs (2, 16, 17, 18) have an outer diameter of 400 to 600 mm, the angle of inclination with respect to the orthogonal is 5 to 10° and the distances between adjacent ring discs (2, 16, 17, 18) are defined by at least three different distance lengths from 20 to 60 mm.
11. Method for equalizing a spread layer (3) of a pourable goods with an equalizing roller (1) according to one of the preceding claims 1 to 10, characterised in that the equalizing roller (1) is positioned at a defined height on the surface of the spread mat (3) above the conveyor or forming belt (5) and rotates in opposite direction to the conveying direction of the forming (5) or conveyor belt, with the circumferential speed of the roller (7) corresponding at least to the conveyor belt speed (V).

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