FI116635B - Rolling, its use, treatment device for thick wood chips and method for conducting wood chips - Google Patents

Description

116635

ROLLER, ITS USE, OVERCUT CHIP TREATMENT DEVICE AND METHOD FOR CONTROLLING WOOD CHIP

VALS, DESS ANVÄNDNING, BEHANDLINGSANORDNING FÖR ÖVERTJOCK FLIS OCH FÖRFARANDE FÖR LEDNING AV TRÄFLIS

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TECHNICAL FIELD OF THE INVENTION

The invention relates to a roll according to the preambles of the independent claims set out below, to its use, to an apparatus for treating over-chipped wood, and to a method for controlling wood chips.

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BACKGROUND OF THE INVENTION

Before cooking, it is appropriate to distinguish between chips which are used as a raw material for cellulose and those which are larger than a certain accepted thickness. The structure of these pieces can then be broken by compression, bending and / or crushing so that they reach the same level of delignification in cooking as the chips of an acceptable size.

Such a treatment is known to be carried out by means of a device in which the over-thick chips are guided to the processing device between two rolls, the rolls rotating substantially * · »· 20 in the opposite directions of rotation. Chips • ·!. As they pass through the roll nip, they form cracks in the direction of the wood and transverse to the root, allowing the cooking chemicals to effectively penetrate into the chips. The structure of the processing device is described in more detail, for example, in Fl 94968.

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The over-thick chips are fed between the rollers of the processing device by a feeder, for example a screen or conveyor, generally perpendicular to the axis of rotation of the rolls. The feeder, such as a screen or conveyor, may be narrower than the rollers of the processor, whereby a chip stream must be sought to be distributed from the feeder device 30 to the entire width of the rolls, e.g. The baffles in the chipping stream are prone to congestion and jams.

2 116635 Efforts have been made to profile the surface of the processing rollers so that the structure of the chips is broken as effectively as possible to allow the absorption of cooking chemicals. At the same time, however, it is advantageous if the processing of oversized chips produces as little fiber loss as possible.

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From Fl 94968 and Fl 962085, a roll of a processing device with a very aggressive surface is known. The surface of the roll is preferably machined with a matrix of pyramidal projections. According to the disclosure, adjacent rolls may be either peaks facing each other or peaks of one roll surface aligned with grooves 10 of another roll surface.

U.S. Pat. No. 5,597,128 discloses a roll of the same type with cross-wound helical V-grooves at equal intervals. There are sharp-pointed, rectangular projections between the V-grooves in the cross. 15 The projections of the first roll overlap the V grooves of the second roll.

In both of the solutions described above, the treatment of the chips is mainly due to the aggressiveness of the roll surface and the sharpness of the projections, rather than crushing and bending the wood chips. This is why reading. ; * 20 results in significant fiber loss and deburring, and the need for compressive force is • »λ 'relatively high. Due to the sharpness of the projections, their wear is also relatively high.

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The Finnish utility model U2412 is known for a roll having 25 radial grooves on its surface which form a wave profile on the surface of the roll and substantially axial grooves which form color lines on the wave profile. The profile peaks of the first roll are located in the profile groove of the second roll. With this type of roller, chipping is more gentle than the aggressive rolls described above, and is based mainly on bending and pressing the chips. 30 The purpose of the transverse axial grooves is to grip the chips and guide them between the rollers. In practice, however, it has been shown that the axial grooves of the utility model do not at all times achieve sufficient adhesion to the chips.

3, 116635

OBJECTIVES AND DESCRIPTION OF THE INVENTION

It is an object of the present invention to reduce or even eliminate the aforementioned problems which occur in the prior art.

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In particular, it is an object of the present invention to provide a roll of an over-thick chips processing device which is capable of breaking the structure of the chips to be treated, effectively allowing absorption of cooking chemicals and generating minimal fiber loss or disintegration. It is also a particular objective that the roll carries the wood efficiently.

The foregoing disadvantages can be eliminated or reduced, and the objects defined above are achieved by the present invention, which is characterized in what is defined in the characterizing part of the independent claims below.

Some preferred embodiments of the invention are described in the dependent claims below.

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A typical roll according to the invention comprises an axis and a roll surface at a distance from the axis. Circular grooves parallel to the periphery of the roll are formed on the roll surface: to form a wave profile on the roll surface, and cross-grooves crossing the peripheral grooves to form color rows on the wave profile. The transverse grooves are substantially different from the axial-25 direction.

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Typically, a roll according to the invention is used in an over-thick chips processing device.

'1 i I; A typical over-chip chip processing device according to the invention comprises a processing roll which rotates in first and second directions about the first and second parallel rotations. The treatment rolls comprise an axis and a roll surface at a distance from the axis formed with 4 116635 circumferential grooves parallel to the roll to form a wave profile on the roll surface and a cross groove to form color lines on the wave profile. The transverse grooves of the roll surfaces of the processing rolls are substantially different from the axial direction. The processing device also comprises a feeding device for guiding the chips between the processing rolls.

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In a typical method according to the invention for controlling wood chips in a processing device comprising a processing roll rotating about first and second parallel rotational axes, wood chips are fed between rotating rolls and compressed, bent and / or crushed between rotating rolls by rolling with substantially different axial directions.

It has now surprisingly been found that by forming on the roll surface both circumferential grooves in the roll circumference 15 and cross-grooves crossing the circumferential grooves substantially deviating from the axial direction of the roll, a very efficient and gentle roll for pressing and bending the wood chips is obtained. This allows a good treatment of the over-thick wood chips and minimizes the amount of waste that is generated during the treatment. Transverse grooves that are substantially different from the axial direction of the roll form * »20 circumferential grooves when cutting into the surface profile of the roll, that is to say, from above, sharp angles which act as effective gripping points for the chips.

. These transverse grooves also serve as effective wood chip control grooves that enhance the spread of wood chips across the entire width of the roll in the wood chips processing device.

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Circular grooves as used herein refer to grooves formed on a roll surface parallel to its periphery. The circumferential groove thus rotates about the roll on its surface, forming an infinite circumference. The circumferential grooves are preferably straight grooves. ^ In some cases, circumferential grooves may also be called radial grooves.

The circumferential grooves normally have a width of 15 to 35 mm, preferably 20 to 25 mm, and the distance between them from the center of the groove to the center of the groove is 15 to 35 mm, preferably 20 to 25 mm. In the case of a sinusoidal wave profile, for example, the width of the groove is equal to the distance from the center of the groove to the center of the adjacent groove.

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In the context of this application, corrugated surface profiling of a roll means that the surface pattern formed by the peripheral grooves is not sharp-angled. In other words, there are no discontinuities in the derivative in the general form of corrugated ring grooves. 5 The waveform can also be represented by, for example, a sinusoid.

According to the invention, the angle α between the cross grooves and the axial direction is 30 to 60 °, preferably 40 to 50 °. Preferably, the cross grooves are straight so that they are corkscrewed about the roll surface of the roll. The cross grooves typically have a width of 5 to 10 mm, preferably 5 to 10 mm, and are typically spaced from 50 to 200 mm, preferably from 50 to 100 mm. As the roll rotates, substantially non-axial grooves act as threads for controlling the chipping current in the axial direction of the roll. By changing the angle α between the cross grooves and the axial direction, the efficiency of the axial displacement of the chips can be controlled.

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In one roll according to the invention, the depth of the cross grooves is at most equal to the depth of the circumferential grooves. This ensures that clear and uniform non-axial grooves are formed on the surface of the roll, by means of which the material stream fed to the roll can be directed over the entire width of the roll. The depth of the non-axial cross grooves formed on the roll surface 20 is typically 3 **, 15 mm, preferably 3-10 mm. The depth of the peripheral grooves is normally 5-20 mm, preferably 7-15 mm.

, * · *. According to the invention, the shape of the cross grooves may vary according to the application and the application. The cross-sectional groove may be, for example: ·: · rectangular, triangular or smooth, ie rounded. The groove shape • · · · can, for example, control the passage of different sized chips into the device. through or axially in different ways.

»· 30 According to one embodiment of the invention, the roll surface of the roll may comprise a detachable one! ... fixed segments, which are formed with the required surface profiling.

The segments are fixed to the roll surface by means of fastening means, for example screws. Removable segments allow for easier maintenance of the roller surface and possible repairs during its operation. A worn segment can easily be removed and replaced with a new one. The roll surface profiling can also be easily changed as needed, for example, when the wood species or chip size changes, by replacing the appropriate segments on the roll surface with old segments. Typically, the size of one single segment is 300 to 500 mm and one roll comprises 30 to 80 segments.

In some cases, the patterning of the roll may also be done directly on the roll surface.

According to one embodiment, the roll surface according to the invention comprises first and second surface portions, wherein the angle between the cross grooves and the axial direction differs. Thus, the roll surface comprises a plurality of areas in which the pattern of the roll surface differs. In the first and second surface portions of the roll surface, the depth, width or distance between the peripheral grooves may be different.

In the first and second surface portions of the roll surface, the depth, width, distance between them or the angle between them and the axial direction may be different in the first and second surface portions. Both the circumferential grooves and the transverse grooves may be different in different parts of the roll surface at the same time.

According to a very preferred embodiment of the invention, the surface of the roll is divided by a virtual symmetry line parallel to the circumferential grooves which divides the surface of the roll into two parts. Then, the first and second surface portions of the roll surface are symmetrical with respect to the symmetry line, i.e. they are mirror images of each other. One can also think that! in such a case, the intersecting grooves form a V pattern having a point 25 on the symmetry line. According to one embodiment, the transverse grooves are then formed by dividing the roll at its center by a symmetry line, the first side of which defines the cross grooves by an angle α and the other side by an angle α. With such an arrangement, for example, a chipping stream fed from a narrow conveyor to the center of the roll can be spread over the entire width of the roll of the processing device without special guide plates or the like.

According to one embodiment of the invention, the roll has a radius of 0.3-0.6 m, preferably 0.4-0.5 m.

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In the oversized chip processing apparatus of the invention, the first and second processing rolls are arranged to rotate at least substantially parallel rotational axes in opposite directions. The processing rolls are arranged opposite each other 5 so that their roll surfaces are spaced apart. In a treatment device according to the invention, the wave profiles of the roll surfaces of the treatment rolls are arranged at a distance from each other. Typically, the shortest spacing between the roll profiles of the roll surfaces of the treatment rolls is 2-8 mm, preferably 3-5 mm.

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In a processing device according to the invention, the wave profiles of the roll surfaces of the processing rolls are arranged to overlap. Thus, the wave peaks of the first roll surface hit the peripheral grooves of the second roll surface. In some embodiments of the invention, the treatment rolls may also be arranged such that the wave peaks of the first and second roll surfaces are opposite, i.e., aligned, as the rolls rotate.

BRIEF DESCRIPTION OF THE FIGURES

The invention will now be described in more detail with reference to the accompanying schematic drawings: 20 'Fig. 1 shows a roller according to an embodiment of the invention, Fig. 2 shows an enlargement of a roller surface according to an embodiment of the invention, 25. Figure 3 shows a detail of the roll surface along line A-A in Figure 2,

Fig. 4 shows a detail B-B of Fig. 2, showing a preferred cross-sectional shape of grooves substantially deviating from the axial direction,

Figures 5 and 6 show some alternative cross-sectional shapes for substantially non-axial grooves, 8 116635

Fig. 7 is a top plan view of a separate segment fastened to the roll surface by screws having a surface according to the invention. Fig. 8 shows a roll according to the invention, the center of which has grooves deviating from the axial direction by angle a and

DESCRIPTION OF THE DRAWING EXAMPLES Figure 1 shows a side view of a roller 1 according to an embodiment of the invention. The roll surface 2 of the roll 1 has a wave pattern formed by arranging the peripheral grooves 3, 3 'of the roll surface 2 of the roll 1. Figure 1 shows the roll surface pattern 4 according to the invention for clarity only on a part of the roll surface. It will be appreciated, however, that in practice, in most cases, the surface of the roll is completely or at least largely patterned in the manner of the invention.

Fig. 2 is an enlarged view of a roll surface 22 according to an embodiment of the invention. The roll surface 22 comprises a plurality of circumferential grooves 23, 23 'which form a soft wavy pattern. The circumferential grooves 23, 23 'form the wave base of the wave profile 20. Figure 2 illustrates the wave profile with lines 5, 5 '. 1 wave peaks. Similarly, a cross groove 6 which crosses a plurality of circumferential grooves 23, 23 'is illustrated. The cross groove is formed by a slot ♦! roll surface 22 at a suitable angle a with respect to the axial direction C of the roll.

Figure 2 shows one gripping unit 7 formed between two adjacent cross-grooves 6, 6 'and two circumferential grooves 23, 23'. Infection Unit 7. the bottom section is in the form of a salmiac pattern, ie oblique. The edges of the peripheral grooves 23, 23 'of the gripping unit 7 are parallel to each other and have a smoothly curved shape. When pressed against these edges, the chips 30 are bent gently. The edges of the tongues 6, 6 'of the crossing grooves 6, 6' of the gripping unit 7 have a sharp shape and these edges effectively grip the chips · '' and apply a shear force along the edge.

9 116635

Figure 3 shows a detail of the roll surface along the sectional surface A-A of Figure 2. The roll surface 32 comprises a plurality of circumferential grooves 33, 33 'which form a smooth wavy pattern. Figure 3 clearly shows the wave peaks 35, 35 'that are formed on the roll surface.

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Fig. 4 shows a detail of the roll surface along the sectional surface B-B of Fig. 2, i.e. the end of the roll, viewed axially. The roll surface 42 comprises a plurality of lattice grooves 46, 46 '. Figure 3 shows a preferred cross-sectional shape of parallel grooves, according to which the cross grooves are formed rounded by 10 notches.

Figures 5 and 6 show some alternative cross-sectional shapes of the cross grooves. In Fig. 5, the transverse grooves 56, 56 'formed on the roll surface 52 are rectangular in cross-section. In Fig. 6, the transverse grooves 56, 56 'formed on the roll surface 52 have a triangular cross-section. In some embodiments, the cross-grooves may also have a cross-sectional shape. It is also possible that the cross-sectional grooves may have different cross-sections in different parts or separate segments of the roll surface. In some special cases, it is possible that the cross-section 20 of a single cross groove varies in different parts of the roll.

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Fig. 7 is a top view of a separate segment 8 to be fastened to the roll surface with screws 8. The corners of the segment 8 have openings 9, 9 ', 9 ", 9"' for the fastening means, -! such as screws. With the fastening means, the segment 8 is removably attached to the »25 roll.

Fig. 8 shows a roll 10 according to the invention. Roll 10 has a virtual symmetry line 11 defined at its center. Roll surface 82 is divided by this. a symmetry line 11 to a first portion 82 'and a second portion 82' which are mirror images of each other relative to the symmetry line 11. Two transverse grooves 86, 86 'are illustrated in Figure 8. In the first portion 82', the transverse groove 86 deviates from the axial direction C by an angle α, and in the second portion 82 'the transverse groove 86' deviates from the axial direction C by an angle α. If the roll 10 ίο 116 635 is rotated in the direction of arrow 87 to move onto the fed wood chips in the middle of the roll.

It will be apparent to one skilled in the art that the invention is not limited to the examples above, but that the invention may vary within the scope of the claims set forth below.

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Claims (16)

116635 A roll (10) comprising: - an axis, 5. a roll surface (82) at a distance from the axis, formed by: - circumferential grooves (3) parallel to the roll to form a corrugated profile, and characterized in that the transverse grooves are substantially different from the axial direction (C). 10 Roll according to Claim 1, characterized in that the depth of the cross grooves is at most equal to the depth of the circumferential grooves. Roll according to Claim 2, characterized in that the cross grooves have a depth of 3 to 15 mm, preferably 3 to 10 mm, and / or the circumferential grooves have a depth of 5 to 20 mm, preferably 7 to 15 mm. Roll according to Claim 1, characterized in that the cross grooves have a width of 5 to 20 mm, preferably 5 to 10 mm, and / or the circumferential grooves have a width of 15 to 35 mm, preferably 20 to 25 20 mm. * Roll according to Claim 1, characterized in that the angle α between the transverse grooves and the axial direction is 30 to 60 °, preferably 40 to 50 °. Roll according to Claim 1, characterized in that the distance between the cross grooves:. between each other is 50-200 mm, preferably 50-100 mm, and / or the distance between the peripheral grooves. 15 to 35 mm apart, preferably 20 to 25 mm apart. Roll according to Claim 1, characterized in that the roll has a radius of 0.3 to 0.6 m; 30 preferably 0.4 to 0.5 m. Roll according to Claim 1, characterized in that the roll surface comprises removable! fixed segments (8). 116635 Roll according to Claim 1, characterized in that the roll surface comprises a first (82 ') and a second surface portion (82'), wherein the angle (a) between the cross grooves (86) and the axial direction (C) differs. 5 Roll according to Claim 9, characterized in that the first and second surface portions are mirror images of one another. Use of a roll according to claim 1 in an over-thick chips processing device. 10 An over-thick chips processing device comprising: - a first and a second parallel rotational axis of a processing roll (10), the processing rolls comprising - an axis (C) and a peripheral roll surface (82) formed at a distance from the axis (3) for forming a corrugated profile on the roll surface, and - for crossing grooves (86) for forming color rows on the corrugated profile, for guiding the feeding device between the processing rolls 20 characterized in that the crossing grooves (86) J, 13. The processing device according to claim 12, characterized in that the wave profiles of the processing rolls *, roll surfaces are arranged to overlap. 25 Processing device according to claim 12, characterized in that the processing rolls •. the wave profiles of the roll surfaces are spaced apart. A processing device according to claim 12, characterized in that the processing rolls; The shortest distance between the wave profiles of the roll surfaces is 2 to 8 mm, preferably 3 to 5 mm. 116635 A method of guiding wood chips in a processing device comprising a processing roll (10) rotating in opposite directions about a first and a second parallel axis of rotation, the method comprising: feeding wood chips between rotating rolls; characterized in that: - the wood chips flow is controlled by axially (C) crosswise grooves (86) on the roll surface (82) of the treatment roll. »*« • * »I 116635