EP1010508B1 - Roller screen or spreading machine - Google Patents

Description

The invention relates to a roller screen or -streumaschine for Classifying or spreading wood chips, fibers or the like, with at least one set of rollers consisting of several, axially parallel arranged side by side, same direction of rotation comprising rolls comprising, together, a roll bed form, which extends in its length transverse to the rollers and a task end for the screen or grit and a discharger for coarse material, each roller with its the Roller bed level defining top to the discharge end turns and a plurality at the same axial distance from each other having spaced annular grooves through each other Ring webs are separated, which are the outer surface of the roller form, and wherein adjacent rollers are assigned to each other are that the annular webs of a roller to the annular grooves of the adjacent Roll opposite and with these - in plan view seen on the roller bed level - largely on its circumference closed, but perpendicular to the roller bed level open Späneddurchfallöffnungen form.

The invention further relates to the use of such Roller screen or spreading machine.

The problems encountered during sieving or classifying as well as a Part of the relevant prior art are in the EP 0 328 067 B1. In this prepublished patent Rollers are placed under protection, whose lateral surface is provided with tapered projections by Tapered valleys are separated. The neighboring ones Rollers are assigned to each other so that each the outer ends of the projections facing each other and from each other are spaced by an axis-parallel gap, the thickness defines the chips to be sieved.

The machine described above can be found in the US patent 2,966,267. Here are the ones with a smooth Bottom trained annular grooves and a smooth outer surface having annular lands each obliquely to the roll axis.

The invention is based on the object, the screening or Klassierwirkung to improve the machine described above.

This object is achieved in that the annular grooves and thus also the separating ring bridges in each case lie perpendicular to the roll axis levels, and that the outer circumferential surface of each ring land by in the circumferential direction adjoining teeth are formed, whose in Direction of rotation in each case leading tooth flank employed steeper is as the adjoining, to the foot of subsequent tooth flank sloping back of the teeth, in axial The ringwalk teeth of a roller saw a slope but opposite to that of the adjacent roller having the same pitch height.

The respective leading tooth flank of the circumferential teeth exerts the particles of the screen or scattering material from a throwing effect, so that blockages of the set of rollers avoided and an accelerated Transport in particular of the coarse material to the pager out be guaranteed. Active impulses only give the leading ones Tooth flanks, while those falling on the tooth ridges Only slide off particles from there. By each in opposite directions ring land teeth rotating through a chip by-pass opening will also clogging these shavings prevented. The separation effect can essentially be adjusted by changing the roller speed. For this purpose, several consecutively connected, each with Rolling sets equipped with variable drives can be provided.

An influence on the separating effect is also different by choice radial tooth heights possible. So can the last Rollers have ring land teeth with maximum tooth height.

In principle it is possible, the bottom of each annular groove smooth surface train. For certain applications, it has However, proved to be advantageous, although the bottom of each annular groove by circumferentially adjoining teeth is formed, the contour of which corresponds to the ring land teeth, the teeth of the annular groove opposite to the annular ridge teeth in Circumferential offset by a fraction of a pitch are and in the radial direction, the tooth backs of the axially adjacent Slightly overhang ring-web teeth.

To jamming of particles of the screen or scattered material in the To prevent grooves, it is expedient if in the direction of rotation the teeth of the annular grooves against the teeth of the ring lands are offset by less than half a tooth pitch.

The throwing effect described above is then particularly effective, when the leading tooth flank with the through the Toothed radius forms an angle of about 45 °.

It is also advantageous if between two adjacent rolls in plan view, a rectilinear gap with a thickness of about 0.2 x tooth height is formed. This relationship yields from the statement that the gap from the load depends on the teeth, the load on large teeth higher is as with fine toothing.

A particularly favorable production process for the rolls can be achieved when each roll of individual prefabricated, on a roll body mounted rings, wherein the roll body of massive rod or dickwandigem Pipe material can exist. The rings can be the same width from e.g. 3 mm, wherein the annular grooves forming rings have an outer diameter compared to the outer diameter the rings forming the ring lands are formed by e.g. only about 2 mm is smaller. To form larger chip drift openings can then two or more identical rings axially next to each other to be ordered.

Is below the set of rollers one against its direction of conveyance provided continuously circulating forming belt, it is to Improvement of the scattering image advantageous if to achieve an additional pneumatic resolution of the chip current of Space between set of rollers and forming band to an air this Room sucking against the conveying direction of the set of rollers Air extraction is connected.

Further features of the invention and their uses are the subject of the dependent claims and will be in connection with further advantages of the invention based on embodiments explained in more detail.

Figur 1

in Draufsicht eine Walzensieb- oder -streumaschine;

Figur 2

das in Figur 1 markierte Detail in vergrößertem Maßstab und schematischer Darstellung;

Figur 3

im Ausschnitt einen Horizontalschnitt durch einen Walzensatz einer Walzensieb- oder - streumaschine, bei der jede Walze aus einzeln vorgefertigten, auf einen Walzenkörper aufgezogenen Ringen besteht;

Figur 4

einen Horizontalschnitt durch eine linke Lagerung einer Walze gemäß Figur 3;

Figur 5

in Stirnansicht in ausgezogenen Linien einen Ring größeren Durchmessers, dem ein in gestrichelter Linie dargestellter Ring kleineren Durchmessers zugeordnet ist;

Figur 6

in vergrößertem Maßstab das in Figur 5 gekennzeichnete Detail;

Figur 7

in schematischer Darstellung einen lotrechten Schnitt durch eine Deckschicht-Streumaschine mit einem über einer Windkammer angeordneten Walzensieb;

Figur 8

in einer Darstellung gemäß Figur 7 die in Figur 7 dargestellte Deckschicht-Streumaschine mit über der Windkammer angeordneten Dosierwalzen;

Figur 9

eine Deckschicht-Streumaschine mit einer Einrichtung für eine zusätzliche pneumatische Auflösung des Spänestromes;

Figur 10

in einer Darstellung gemäß Figur 7 eine Mittelschicht-Streumaschine mit einem über einem Bunker angeordneten Walzensieb;

Figur 11

eine Ausführungsform gemäß Figur 10 mit geänderter Walzensiebanordnung und

Figur 12

einen Deckschicht-Walzenstreukopf gemäß Figur 9 sowie im oberen Teil der Figur ein mit dieser Walzenstreumaschine erzielbares Streubild.

In the drawing, some exemplary embodiments of the invention are shown. Show it:

FIG. 1

in plan view, a roller screen or spreading machine;

FIG. 2

the marked in Figure 1 detail on an enlarged scale and schematic representation;

FIG. 3

in section a horizontal section through a set of rollers of a roller screen or - scattering machine, in which each roller consists of individually prefabricated, mounted on a roller body rings;

FIG. 4

a horizontal section through a left bearing a roller according to Figure 3;

FIG. 5

in front view in solid lines a ring of larger diameter, which is assigned a shown in dashed line ring of smaller diameter;

FIG. 6

on an enlarged scale, the detail marked in FIG. 5;

FIG. 7

in a schematic representation of a vertical section through a cover layer spreader with a arranged over a wind chamber roller screen;

FIG. 8

in a representation according to Figure 7, the cover layer spreader shown in Figure 7 with arranged above the wind chamber metering rollers;

FIG. 9

a topcoat spreader having means for additional pneumatic dissolution of the chip stream;

FIG. 10

in a representation according to Figure 7, a middle-layer spreader with a arranged over a bunker roller screen;

FIG. 11

an embodiment according to Figure 10 with a changed roller screen arrangement and

FIG. 12

a covering layer roller scraping head according to FIG. 9 and, in the upper part of the figure, a spreading pattern achievable with this roller spreading machine.

Figure 1 shows a roller screen or grinder for classifying or sprinkling wood chips, fibers or the like. Shown is a set of rollers 1, which consists of several, paraxial arranged side by side, same direction of rotation. 2 (see Figure 5) comprising rollers 3, which together form a roller bed, which is transverse in length to the Roll 3 extends and a task end A for the sieve or Has grit and a discharge B for coarse material. Every roller 3 rotates with its top surface defining the roller bed level to the discharging B and has a variety of in the same axially spaced annular grooves 4 (see Figure 2), which are separated from each other by annular webs 5, the form the outer circumferential surface of the roller 3. The annular grooves 4 and so that they also separating ring ridges 5 are each in perpendicular to the roll axis 6 stationary planes, with adjacent Rollers 3 are assigned to each other so that the annular webs. 5 of a roller 3 opposite the annular grooves 4 of the adjacent roller and with these - in plan view of the roller bed level seen - on its circumference largely closed, vertical However, open to the roller bed level open Spededdurchfallöffnungen 7 form, as can be seen Figure 2. The width b the ring lands 5 maximum as large as that of the annular grooves 4. In particular Figure 2 also shows that between two adjacent Rolls 3 in plan view a geradlinier gap 8 is formed is.

According to the embodiments shown in Figures 3 to 5 the roller 3 consists of individual prefabricated, on a roller body 9 mounted rings 10, 11. In this case, the roller body 9 made of solid rod or thick-walled pipe material consist. In particular, let the figures 3 and 4 recognize that the rings 10 of larger diameter that in Figure 2 schematically illustrated annular webs 5, the rings 11 smaller Diameter, however, each embedded between two ring lands Ring grooves 4 form.

The outer circumferential surface of each annular web 5 is as well as the Bottom of each annular groove 4 through each other in the circumferential direction subsequent teeth 12 formed, whose in the direction of rotation of the second each leading tooth flank 12a is employed steeper than adjoining, until the foot 12b of the following Tooth flank 12a sloping tooth back 12c. This includes the leading tooth flank 12a with the laid by the tooth root 12b Radius r an angle α of about 45 °. Figure 6 also leaves recognize that each tooth back 12c of the ring land teeth 12 with the tangent to its circle of motion is at an angle y of 3 ° -6 °.

The teeth 12 of the annular grooves 4 are similar to those of the annular webs fifth formed, but in the circumferential direction by one Fraction of a tooth pitch t, preferably less than one offset half tooth pitch t. Figure 5 shows that the Ring groove teeth 12 in the radial direction of the tooth back 12c of slightly surmount axially adjacent ring land teeth 12.

Seen in the axial direction, the annular land teeth 12 form a Gradient 13, which is shown schematically in Figure 3. Around as even a chip distribution over the width of the To achieve roll bed, it is useful if this slope 13 of the adjacent roller is opposite but the same Has pitch height.

According to Figures 3 and 4, the rings 10, 11 in the axial direction by front-right and left-handed nuts 14a and 14b braced against each other. For positive rotary connection of the rings 10, 11 with the roller body 9, the rings with a nose 15 (Figure 5) in a over the length of the roll body 9 extending groove intervene. In a functional, in the drawing not shown alternative solution can Instead, on the lateral surface of the roller body 9 with a Slope be provided a projection on which the rings 10, 11th be pushed with a recess in its inner ring contour can.

The separating effect of the inventive roller screen or Spreading machine is adjustable by changing the roller speed. In addition, larger swarf holes can be formed to form 7 each two or more identical rings 10 and 11 are arranged axially side by side. The width can be b of a ring 10 or 11 e.g. 3 mm. With an outside diameter D of about 60 - 70 mm (top coat machines) can each ring 10 or 11 e.g. 16 - have 20 teeth 12 and at an outer diameter D of about 70-80 mm (middle layer machines) are per ring e.g. 14 - 24 teeth provided. In broad Spreaders are the outer diameter up to 100 mm. The radial tooth height h depends on the application and is in Top coaters about 1 - 3 mm and in middle-layer machines about 2 - 8 mm. The ring groove teeth are opposite the ring land teeth in the direction of rotation 2 only by an angle β of about 4 ° offset.

According to FIG. 4, each roller 3 can be stored at both ends in pedestal bearings 16 be. The roll surface is wear-resistant, preferably chromed.

FIG. 7 shows a cover layer spreader 17 with a chip bunker 18 for receiving the screening or spreading material 19, with a Bunker belt 20, the screenings 19 in the direction of the drawn Dart to a discharge point promotes, with in the chip bunker 18 arranged leveling rollers 21 for the screenings 19 and one of the pre-conveyed screenings 19 stripping at the discharge point Spiked roller 22. Below the discharge area is a provided with seven 23 fitted wind chamber 24, in the for the Arrows symbolized by horizontal horizontal air flow 25 are arranged, which are connected to an air blower 26 are.

Below the said band discharge point of the bunker belt 20 a roll set 1 according to the invention is arranged, which serves as a roller screen works, ie chip diarrhea openings 7 of the same size and is used for the separation of coarse material 27, which over the Roll set 1 migrates from the task end A to the discharge end B and is dropped into a screw 28.

FIG. 8 differs from the cover layer spreading machine 17 according to Figure 7 only in that the roller set 1 here as Dosing device works, so for the classification of the material to be spread 19 serves. The size of the Spededdurchfallöffnungen shown in Figure 2 7 therefore increases from A to B. Any coarse material will also dropped here in the screw 28.

In Figure 9, a cover layer spreader is shown at the chip stream is mechanically and pneumatically dissolved. The chip bunker 18 corresponds with its internals 20, 21, 22 in essentially the embodiment according to FIG. Grit 19 is thus from the bunker belt 20 in through the leveling rollers 21 promoted Förderhöhe promoted and at the end bunker belt 20 with the assistance of a rotating spiked roller 22, which can also be a rotating brush, on one discarded by scattering rolls set of rolls 1. In one Clear distance below the set of rollers 1 is the usual shape band 31, in the direction of the arrow and thus rotates counter to the conveying direction 33 of the set of rollers 1. The roll set 1 is followed by a coarse-part screw 28. To achieve an additional pneumatic resolution of the chip stream is the space between the set of rolls 1 and Formband 31 to a the air of this space against the conveying direction 33 of the set of rollers 1 suctioning air suction 34 connected. This is between the beginning A of the set of rollers 1 and the air extraction device shown on the outside right in FIG 34 above the forming belt 31 a free suction 35 formed. The air suction device 34 generates below of the set of rollers 1 and above the forming belt 31 air speeds from 0.9 to 1.7 m / s. This gives you next to the caused by the set of rolls 1 mechanical resolution of the Chip current still in addition a pneumatic resolution.

Figure 10 shows a middle layer spreader 29. Here is running the sieve or spreading material 19 to be introduced into the chip bunker 18 first on a working as a roller screen set of rolls 1, the already separates the coarse material and drops into the screw 28. The screened material is collected by a conveyor belt 30 and dropped in the chip bunker 18. That of his bunker belt 20 dropped sieve or grit 19 is in a here not more interesting device divided into two sub-streams and then passes to a forming belt 31, as well as in the Figures 7 to 9 is provided.

The embodiment according to FIG. 11 differs from that of FIG of Figure 10 only in that by the as a roller screen working roll set 1 passing sieve or grit 19th immediately falls into the chip bunker 18.

Figure 12 shows in its lower part in a schematic representation a plant corresponding to Figure 9, in which the chip stream should be resolved mechanically and pneumatically. The Screening or spreading material, not shown in more detail Way promoted by a bunker belt 20 and at the end of the tape with Supporting a rotating brush 32 on one by scattering rollers dropped set of rolls 1. At a clear distance below the set of rollers 1 is the usual Formband 31 pointing in the direction of the arrow and thus rotates counter to the conveying direction 33 of the set of rollers 1, for achieving the chip replica shown in the upper part of FIG. 12 but was stopped. Between the beginning of the A Roller set 1 and a bottom right in Figure 12 shown on the outside Air suction device 34 is above the forming belt 31st a free suction channel 35 is formed whose length at least the of the set of rolls 1 corresponds. In addition to the through the roller set 1 obtained mechanical resolution of the chip current is obtained In addition, a pneumatic resolution, which in addition to the upper Part of Figure 12 shown Spänestreubild leads. This Scattering image has resulted at a speed of the scattering rollers. 3 of 325 rpm and at an air velocity generated by the exhaust of 1.1 m / s. The scattering took place over one Period of 30 seconds when the mold belt 31 is stationary.

The scatter plot shows that while still the highest scattering height below the first scattering rollers of the set of rollers 1 shows that this maximum but significantly lower lies as without air suction, which leads to a strong pulling apart of the scattering pattern on the forming belt, wherein the extension of the spreading pattern caused by the air suction until far below the bunker belt 20 takes place.

Claims (27)

1. Roller screen or spreading machine for the classification or dispersing of wood chips, fibers, or similar materials, with at least one roller set (1) composed of several rollers (3) aligned axially parallel and having the same rotation direction (2); these rollers create a roller bed that extends longitudinally at right angle to the rollers (3) and is provided with an input end (A) for the introduction of the material to be processed (19) and with an output end (B) for coarse material (27); each roller's (3) upper side which defines the plane of roller bed turns toward the output end (B) and is equipped with numerous annular grooves (4) axially equi-spaced and separated by annular crosspieces (5) that form the outer sheathing surface of the roller (3); adjoining rollers (3) are so arranged that the annular crosspieces (5) of one roller (3) are opposite the annular grooves (4) of the adjoining roller, thus forming a largely closed surface, if viewed from the top of the roller bed surface, yet forming openings for the passage of chips (7) characterized in that the annular grooves (4) as well as the annular crosspieces (5) are placed in a plane which is perpendicularly to the roller axis (6) and that the outer sheathing surface of each annular crosspieces (5) has circumferentially aligned teeth (12) whose rotation direction (2) leading side (12a) is shaped steeper than the tooth back side (12c) leading to the base (12b) of the following tooth side (12a), whereby, as seen axially, the annular crosspiece teeth (12) of a roller (3) form a gradient (13) that is opposite to that of the adjoining roller (3) but has the same gradient height.
2. Roller screen or spreading machine according to claim 1, characterized in that the tooth leading side (12a) of the annular crosspiece teeth (12) makes an angle of about 45 degrees with the radius of the tooth base (12b). (figure 6)
3. Roller screen or spreading machine according to claim 1 or 2, characterized in that each tooth back (12c) of the annular crosspiece teeth (12) makes an angle of 3 to 6 degrees with the tangent of their revolution circle. (figure 6)
4. Roller screen or spreading machine according to claim 1, 2 or 3, characterized in that the bottom of each annular groove (4) is formed by a circumferential row of connected teeth (12) whose contours correspond to those of the annular crosspiece (12), whereby the teeth (12) of the groove (4) are opposite to the annular crosspiece teeth (12) and are cicumferentially offset by a fraction of a tooth part (t) and axially slightly overlap the tooth backs (12c) of the adjoining annular crosspiece teeth (12). (figure 5)
5. Roller screen or spreading machine according to claim 4, characterized in that in the rotation direction (2), the teeth (12) of the annular grooves (4) are offset against the teeth (12) of the annular crosspiece (5) by less than half of a tooth part (t). (figure 6)
6. Roller screen or spreading machine according to one of the preceding claims, characterized in that the width (b) of the annular crosspieces (5) is at most as wide as the width of the annular grooves (4).
7. Roller screen or spreading machine according to one of the preceding claims, characterized in that the width (b) of the annular crosspieces is about 3-9 mm.
8. Roller screen or spreading machine according to one of the preceding claims, characterized in that a rectilinear slot (8) (top view) is created between two adjoining rollers (3), having a size of about 0.2 x tooth height (h). (figure 2)
9. Roller screen or spreading machine according to one of the preceding claims, characterized in that the radial tooth-height (h) is about 1-8 mm.
10. Roller screen or spreading machine according to one of the preceding claims, characterized in that the annular crosspieces (5) have an outer diameter (d) of about 60-80 mm and have sixteen to twenty four teeth (12).
11. Roller screen or spreading machine according to one of the preceding claims, characterized in that the annular crosspieces (5) and grooves (4) are applied to a single roller body consisting of a solid rod or of thick wall pipe.
12. Roller screen or spreading machine according to one of claims 1 through 10, characterized in that each roller (3) is composed of axially clamped rings (10, 11) jointly applied.
13. Roller screen or spreading machine according to one of claims 1 through 10, characterized in that each roller (3) consists of single pre-fabricated rings (10, 11) drawn on the roller body (9).
14. Roller screen or spreading machine according to claim 13, characterized in that the rings (10, 11) are braced in the axial direction by (front view) right and left-handed nuts (14a, 14b).
15. Roller screen or spreading machine according to claims 13 or 14, characterized in that to obtain a definitive connection of rings (10, 11) to the roller body (9), an inclined protuberance is provided on the sheathing surface of the roller body (9) on which rings (10, 11) provided with an appropriate slot, are inserted.
16. Roller screen or spreading machine according to claim 13, 14 or 15,
    characterized in that for the formation of larger chip passage openings (7) two or more identical rings (10, 11) are axially arranged next to each other.
17. Roller screen or spreading machine according to one of the preceding claims, characterized in that each roller (3) is housed at both ends in bearings (16).
18. Roller screen or spreading machine according to one of the preceding claims, characterized in that the roller surface is abrasion resistant, preferably chrome-plated.
19. Roller screen or spreading machine according to one of the preceding claims, characterized in that the separation effect can be regulated by modification of the roller revolution velocity.
20. Roller screen or spreading machine according to one of the preceding claims, characterized by at least two roller sets, whereby the rollers (3) of the first set in the direction of travel have wider annular grooves (4) and annular crosspieces than those of the first roller set.
21. Roller screen or spreading machine according to claim 20, characterized in that the second roller set is located at a lower level than the first roller set.
22. Roller screen or spreading machine according to one of the preceding claims, with a form belt (31) continuously running opposite to the travel direction (33) and located beneath the roller set (1), characterized in that, to achieve a supplemental pneumatic loosening of the chip stream, an air suction device (34) is attached to provide a countercurrent air stream in the space between roller set (1) and form belt (31). (figure 12)
23. Roller screen or spreading machine according to claim 22, characterized in that between the input end (A) of the roller set (1) and the air suction device (34) and above the form belt (31), a free suction channel (35) is created, whose length is at least as long as the roller set (1). (figure 12)
24. Roller screen or spreading machine according to claim 22 or 23, characterized in that the air suction device (34) produces air velocities of 0.9-1.7 meters/sec. below the roller set (1) and above the form belt (31). (figure 12)
25. Roller screen or spreading machine according to one of claims 1 through 21, characterized by its use as a roller sieve in a deck-layer dispersion machine (17) above a wind chamber (24). (figure 7)
26. Roller screen or spreading machine according to one of claims 1 through 21, characterized by its use as a dosing roller in a deck-layer dispersion machine (17) above a wind chamber (24) and/or a suction channel (35). (figures 8 and 9)
27. Roller screen or spreading machine according to one of claims 1 through 21, characterized by its use as a roller sieve over a chip bunker (18) of a middle layer dispersing machine (29). (figures 10 and 11)

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