DE4439271B4 - Process and plant for the continuous production of a multilayer wood panel - Google Patents

Abstract

Procedure according to DE 44 34 876 for the continuous production of a multilayer board from a mixture of fine, coarser and long lignocellulosic and / or cellulosic particles mixed with binder, such as shavings, fibers and long chips or the like, consisting of a core layer with a plurality of core layer layers of oriented scattered long chips and the surrounding two fine chips - Cover layers, whereby the individual core layer layers are scattered from scattering stations onto a continuously moving forming belt to form a pressed material mat, whereby a fine chip / chip mixture with a moisture content that is 80% to 100% higher than that of the long-chip mixture for the core layer on the forming belt first the lower cover layer is scattered and then pre-compacted to a fine chip mat, several core layer layers of oriented long chips for the core layer are then sprinkled on the pre-compressed fine chip mat, followed by a fine layer pan-chip mixture with a moisture 80% to 100% higher than that of the long-chip mixture for the core layer on an auxiliary scattering belt over the last core layer layer the top cover layer ...

Description

The invention relates to a method and a plant for the continuous production of a multilayer wood panel according to a patent DE 44 34 876 ,

at The core of this multilayer board consists of a three-layer Langschnitzel Scattering (in the Oriented Strand Board or called OSB for short). This means, the two outer layers this core plate are approximately 4 cm to 10 cm long and 1 cm Long slices up to 3 cm wide are strewn lengthways. The middle class consists of the same long chips, but offset by 90 ° across the longitudinal scatter. Such long-chip boards are, however, with fine veneers (approx 0.3 mm to 0.5 mm thickness) not coatable, mainly because of the surface of this Coarse chipboard by bulk topography not a sufficiently smooth surface results. Also through subsequent Sanding the surfaces can this surface structure therefor cannot be improved sufficiently. For particularly high-quality construction material panels as replacement for Plywood panels therefore have such long-chip panels, which the thickness was previously calibrated by grinding, later with relatively thin ones Chipboard / fiberboard (medium density Fiber or MDF for short) - off Fibers or chips approximately 2 mm to 2.5 mm thick - coated on both sides.

To the pressing of these three individual plates, the upper and lower Cover layer plate and the three-layer core plate, the so-called five-layer plate can these are coated with fine veneers and is therefore a replacement product for one high quality coated plywood board.

The The main application was based on the task of specifying a method with the one inexpensive Production of a multilayer board of the specified type in a continuous manner way of working possible is in order to achieve a noticeable increase in press speed and production output to achieve.

The Continuous production of the multilayer board has been particularly achieved in that the Fine material / fiber cover layers pre-compressed and with the core layer together in a continuously working press to the five-layer board pressed were.

On Disadvantage, however, is that the Long chips on the surface no smooth surface structure in the last or topmost scattered OSB layer established. The behavior of the long chips results in a relatively chaotic structure of the surface in which the schnitzel partially upright so that when the pre-compacted is placed upper cover layer there is a risk that this is vertically upwards standing up long chips in the direction of transport of the pressed material mat climb and in the subsequent joint compression in the front Visually telegraph the infeed area of the continuously operating press, this means, after leaving the finished pressed plate from the continuously working Press can despite the relatively smooth surface due to the top layer an optically visible cloudy surface structure notice, because the tips of the long chips come from the at least joint pressing in the front inlet area puncture or damage the lower area of the top layer. The surface structure that arises is for coating by plastic laminates or wood veneers is still suitable however, this surface is not for painting such surfaces homogeneous enough. With these very inhomogeneous surface structures, if had to be painted very high amounts of paint required, around the faulty surfaces to cover / cover in color, which was associated with very high costs.

The DE 42 18 444 A1 already shows a process with which spatially deformable molded parts for the interior lining of vehicles can be produced from a binder-containing lignocellulose or wood fiber multilayer mat, the outer layers defining the surfaces having a higher compression than the inner layers, which consist predominantly of the same material , Each of the outer layers is formed from a multiplicity of individual layers whose fiber arrangement is oriented approximately orthogonally to one another. Layers that are not offset and moisture in the fine chip / chip mixture are also provided. However, several core layers are not included.

With the DE 37 30 776 A1 a multilayer chipboard is known, which is made of at least one middle layer with wood chips and at least one wood glue and adjacent top layers with wood chips and at least one wood glue using pressure and heat. From this disclosure, layers of staggered long chips for a core layer are not offset from one another and there is no indication of the moisture content of the chip-fiber mixture for the outer layers.

The method and device also belong to the prior art EP 0 162 118 A1 to achieve a predeterminable basis weight distribution in the transverse direction of a nonwoven to be shaped for the production of chipboard, fiber and similar boards. Then, in order to save chip material and to improve the spreading results for the basis weights of stripe-shaped areas adjoining one another in the transverse direction of the preliminary fleece, representative measured values are formed and the height of each of these stripe-shaped non-woven area based on a flat metering conveyor belt as a function of the respectively associated measured value by influencing one of them Regarding the non-woven area associated with the non-woven member.

On obvious advice on the solution below The task cannot be determined from this prior art.

The Invention is based on the object, the method and the system according to the main application to improve so that the Do not penetrate long chips into the outer layers. The solution to this Task is specified in the characterizing part of claims 1 and 2.

With the inventive method is achieved that a optically perfect smooth surface on the multilayer board can be produced. With the plant according to the invention are in particular by the smoothing device flawless surface structures achieved, which also has a paintability with low paint application possible is. Due to the lower, very thin coat of paint is also given an economic advantage. To prevent getting up again the long sliver after all five layers have been joined to form the mat it may be advantageous between the heat tunnel and the drop point to provide a further additional pre-press for the upper cover layer. This pre-press can be arranged between the main press and the heat tunnel also be appropriate.

preferred Refinements and developments of the invention are specified in the subclaims.

On embodiment the invention is explained below with reference to the drawing.

It demonstrate:

1.1 and 1.2 in a schematic representation the system for performing the method according to the invention and

2 a section C on a larger scale 1.1 ,

The solution according to the invention is clearly shown in FIG 2 out. After that is a smoothing device 44 provided immediately below the pre-press 11 for the top cover layer 32 and the handover nose 12 is arranged. This smoothing device 44 consists of at least one leveling roller 45 that surface so far 52 the core layer 35 is pressed that the vertical long chips 50 be rolled flat on the surface. To re-erect the long chips 50 after leaving the leveling rollers 45 a hold-down plate must be prevented immediately afterwards 46 provided the end of which is reversible 51 of the system 44 as close as possible below the surface 49 the top layer mat 32 placed so that the distance w between the feed point of the top layer 32 and the top 47 of the bed plate 46 is chosen so small that in the course of the throughput speed in the transport direction 48 who have favourited Long Schnitzel 50 prevented from getting up again and the pre-compacted top layer mat 32 on the calm surface of the core layer 35 can hang up. To re-erect the long chips 50 and penetration into the top layer 32 an additional pre-press can also prevent this 53 above the five-layer mat 4 between heat tunnel 28 and the point of application for the upper cover layer 32 be arranged. It may also be appropriate to use the pre-press 53 between heat tunnel 28 and the continuously working main press 3 to be arranged (not shown).

In 1.1 and 1.2 divided into two sheets, the structure of the system for carrying out the main filing method according to the invention is shown.

• – kontinuierlich arbeitende Hauptpresse 3,
• – Formband 1 mit Übergabenase 20,
• – Streustationen 6, 7, 8, 9 und 10,
• – Warmwassersprüheinrichtungen 5 und 15 sowie Heißgasbedüsung des Streugutes und Warmhaltetunnel 28 unterhalb und oberhalb des Formbandes 1.

Conceptually, the plant for carrying out the process is divided into five plant sections:

• - continuously working main press 3 .
• - forming tape 1 with handover nose 20 .
• - spreading stations 6 . 7 . 8th . 9 and 10 .
• - Hot water spray devices 5 and 15 as well as hot gas spraying of the spreading material and holding tunnel 28 below and above the forming belt 1 ,

Geometric the system is divided into Formstrasse I and continuous working main press II.

• a) Warmwasserbesprühung des unteren Formbandes 1 mit Warmwassersprüheinrichtung 5,
• b) Streuung der unteren Deckschicht 31 auf Formband 1 mit vorgewärmten Spänen/Fasern aus der Streustation 6,
• c) Vorverdichtung der unteren Deckschicht 31 durch Vorpresse 2,
• d) nacheinander erfolgende Streuung der drei Kernschichtlagen 33, 34 und 35 durch die Streustationen 7, 8, und 9 mit Langschnitzel auf die untere Deckschicht 31,
• e) Streuung der oberen Deckschicht 32 auf das Streuband 30 durch die Streustation 10,
• f) Vorverdichtung der oberen Deckschicht 32 mit Formband 30 und Vorpresse 11 und Übergabe durch Übergabenase 12 auf die oberste Kernschichtlage 35,
• g) Funktionsbereich mit Metalldetektoren 13, Längsbesäumung 14, Wasserbesprüheinrichtung 15 auf die obere Deckschicht 32 und reversierbarer Übergabenase 20 mit Abwurfbunker 21 und
• h) Preßstrecke der kontinuierlich arbeitenden Hauptpresse 3 mit vorbeheizten Stahlbändern 27 zur Naßdampferzeugung mit Winkel Alpha im Einlaufbereich der befeuchteten Deckschichten 31 und 32 und der nachfolgenden schnellen Verdichtung im Kompressionsbereich mit Winkel Beta.

Both areas are structured geometrically as follows:

• a) Hot water spraying of the lower forming belt 1 with hot water spray device 5 .
• b) Scattering of the lower cover layer 31 on ribbon 1 with preheated chips / fibers from the spreading station 6 .
• c) Pre-compaction of the lower cover layer 31 by pre-press 2 .
• d) successive scattering of the three core layer layers 33 . 34 and 35 through the spreading stations 7 . 8th , and 9 with long chips on the lower surface layer 31 .
• e) Scattering of the top cover layer 32 on the scatter band 30 through the spreading station 10 .
• f) Pre-compaction of the top layer 32 with ribbon 30 and pre-press 11 and handover by handover nose 12 to the top core layer 35 .
• g) Functional area with metal detectors 13 , Longitudinal edging 14 , Water spraying device 15 on the top cover layer 32 and reversible transfer nose 20 with discharge bunker 21 and
• h) press section of the continuously operating main press 3 with preheated steel bands 27 for wet steam generation with angle alpha in the inlet area of the moistened cover layers 31 and 32 and the subsequent rapid compression in the compression area with angle beta.

The multilayer board 42 is to be produced in a continuous manner so that there is only one transition with a relatively small transfer gap between the forming line I and the continuously operating press II 29 from the handover nose 20 to the decreasing lower steel band 27 the continuously working press 3 gives.

The separate forming belt 30 , whereupon the fines distribution station 10 Scatters is the continuously working pre-press 11 assigned. The upper pre-compacted mat is made with the forming tape 30 and handover nose 12 the core layer mat and the lower cover layer 31 fed.

Due to hot air flow, the scattering stations 7 . 8th and 9 , for example in eddy current chambers 41 , the chips / fiber material are preheated to an elevated temperature in the range from 60 ° Celsius to 80 ° Celsius. However, it makes sense to connect such eddy current chambers 41 only immediately before or in the spreading stations.

On the lower ribbon 1 that also as a feed belt for the mat 4 is used by means of a water spray device 5 the warm water trickled. That on the ribbon 1 sprinkled water is immediately removed from the surface of the chips / fiber top layer 31 absorbed. The thick steel bands 27 are more wear resistant at the same time. The double joint with the joint heating plates 24 to DE 43 01 594 A1 is set so that the front area with the hydraulic actuators 25 , with a very flat setting angle Alpha, just the upper layer of fine material 32 Inked with increased water moisture. The warming tunnel described below is used to maintain heat 28 intended. The forming tape 1 is by means of the drive station 36 among the water spray devices 5 and 15 and spreading stations 6 . 7 . 8th . 9 , and 10 pulled through, that means it glides over a so-called table level 37 , This ribbon 1 - made of plastic - glides over flat surfaces, which are coated with a good sliding material, such as plastic. In the 1.1 and 1.2 is the table level 37 through the pre-press 2 and the metal detector (metal detector) 13 interrupted. So much for the table level 37 is not interrupted by the above-mentioned function holders, it is replaced by heating plates 17 supported. Through these hot plates 17 becomes the table level 37 Constantly tempered to a temperature between 40 ° Celsius and a maximum of 80 ° Celsius.

Between the last spreading station 10 and the upper pulley 22 the continuously working press 3 (see distances f and g in 1.1 and 1.2 ) is opposite the lower closed forming belt 1 the system open. In order to protect the preheated grit and the preheated spray water against radiation upwards, a radiation protection hood that can be raised and lowered vertically is provided for reasons of accessibility (maintenance), which in turn also has heating plates 16 is provided, so that at least in the black beam region, radiation between 40 ° Celsius and a maximum of 80 ° Celsius in the direction of the spreading material is effected.

The transfer of the pressed material mat 4 in the gap area takes place on the steel strip inlet bend 39 , which is also below the steel belt 27 the roller bars 23 on the heated rolling surface 43 the continuously working press 3 be handed over. The front handover nose 20 (with approximately 12 mm to 20 mm diameter) is around the forming belt 1 pulled around and can be reversed horizontally in accordance with the reversing stroke K, so that in the event of a malfunction of the scattering mechanism for the five layers, that is to say an incorrect pouring, the mat of pressed material 4 by quickly retracting the transfer nose 20 in the discharge bunker 21 can be poured off and disposed of quickly. The return speed over the stroke K is faster than the belt speed of the steel belt 27 the continuously working press 3 , This creates the mat tear 40 immediately at the right extreme position of the transfer nose 20 of the ribbon 1 , At this point of breakage there is a risk that fragments of the pressed material mat 4 on the lower steel belt running up at an angle 27 fall and thus uncontrolled with sticking through isocyanate of the middle long chip layers by the continuously working press 3 with the tighter press gap Y can be driven. For this reason, the discharge bunker 21 with a swiveling metal flap 18 provided around the pivot point 19 , can be pivoted against the transport direction. The front right tip of this sheet metal flap 18 lies in the transport direction to the right of the potential mat tear point already described 40 , so that remnants from the mat tear 40 targeted to the sheet metal flap 18 fall. The front tip of this sheet metal flap 18 is at a very short distance from the steel belt 27 (approx. 2 mm to 10 mm) positioned. By swiveling the sheet metal flap 18 , contrary to the direction of transport, the remaining pieces caught on this sheet from the incorrect fill into the discharge bunker 21 folded. Before the handover nose 20 from the rear reversing position back to the front position for loading the continuously operating press 3 is moved forward, the flap is pivoted back into the starting position in the transport direction. Reversing the transfer nose 20 done by the reversing drive 38 to the reversing stroke K.

Claims (5)

Procedure according to DE 44 34 876 for the continuous production of a multilayer board from a mixture of fine, coarser and long lignocellulosic and / or cellulosic particles mixed with binder, such as shavings, fibers and long chips or the like, consisting of a core layer with a plurality of core layer layers of oriented scattered long chips and the surrounding two fine chips - Cover layers, whereby the individual core layer layers are scattered from scattering stations onto a continuously moving forming belt to form a pressed material mat, whereby a fine chip / chip mixture with a moisture content that is 80% to 100% higher than that of the long-chip mixture for the core layer on the forming belt first the lower cover layer is scattered and then pre-compacted to a fine chip mat, several core layer layers of oriented long chips for the core layer are then sprinkled on the pre-compressed fine chip mat, followed by a fine layer pan-chip mixture with a moisture 80% to 100% higher than that of the long-chip mixture for the core layer on an auxiliary spreading tape over the last core layer layer, the upper cover layer and pre-compacted to a second fine chip mat, placed on the top core layer layer and thus forming the pressed material mat after transfer to the main press area using pressure and heat to the multi-layer board is pressed and cured, characterized in that after scattering the uppermost core layer layer its surface is smoothed down until shortly before the upper cover layer is deposited by means of contact pressure. System for carrying out the method according to claim 1, comprising a plurality of scattering stations assigned to the cover layers and core layer layers for forming the material to be pressed and a heatable continuously operating main press, the scattering stations for the cover layers having a superheated steam device and / or hot air device and the scattering stations the core layer layers are equipped with a hot air device and as a further structure the system for the lower cover layer and for the upper cover layer has a pre-press and from the pre-press for the upper cover layer to the continuously working main press has a heat tunnel, characterized in that after the spreading station ( 9 ) for the top core layer ( 35 ) a smoothing device ( 44 ) consisting of one or more leveling rollers ( 45 ) with the following hold-down plate ( 46 ) is arranged. Installation according to claim 2, characterized in that the smoothing device ( 44 ) below the spreading band ( 30 ) for the upper pre-press ( 11 ) the top layer ( 32 ) is arranged reversibly. System according to claims 2 and 3, characterized in that between the pre-press ( 11 ) for the top cover layer ( 32 ) and the heat tunnel ( 28 ) over the mat ( 4 ) Metal detectors ( 13 ) are arranged. System according to claims 2 and 3, characterized in that between the continuously operating main press ( 3 ) and the heat tunnel ( 28 ) an additional pre-press ( 53 ) for the pressed material mat ( 4 ) is arranged.