DE102017111134B4 - Method and plant for producing a chipboard - Google Patents

Abstract

The present invention relates to a method and a plant for producing a multi-layer chipboard with outer and compared to the middle layer thinner cover layers, which used to scatter the middle layer glued and preferably dried chips, wherein the chips in at least one screening device (S) sieved and in at least four fractions (F1, F2, F3, F4) are divided into increasing grain size, based on the grain size, the first fraction (F1) with the smallest grain size excluded from the production process, the second fraction (F2) with a larger particle size for scattering the cover layers, which is further provided next larger third fraction (F3) substantially for the production of the middle layers and the largest fourth fraction (F4) for post-comminution. The invention consists in dividing the third fraction (F3) into two partial fractions (F3a, F3b), wherein
the first fraction (F3a) having the smaller grain size is used for post-shredding and then the second fraction (F2) is used for the top layers and the second fraction (F3b) is the larger grain size for producing the middle layer.

Description

The present invention relates to a method for producing a chipboard according to the preamble of claim 1 and a system for producing a chipboard according to the main claim 12th

In the production of material plates from scatterable materials, a mixture of particles or fibrous materials and a binder is scattered to a grit mat on a forming or conveyor belt, the grit mat is then fed to any necessary pretreatment and finally a compression. The compression can be carried out continuously or discontinuously by means of pressure and / or heat. The usual material plates that are produced in this case are usually MDF, chipboard or OSB boards or comparable multilayer boards. Orientable grit is used especially for OSB boards.

The present invention is concerned with the production of particle boards, which are usually produced at least three layers, as for example from WO 03/074243 A1 is known. Here, between the cover layers of the finest material used, at least one layer with suitable shavings which, combined with a cured binder, define the rigidity and load-bearing capacity of a pressed chipboard. Standard shavings for the middle layers are usually 15 mm to 30 mm long on average and 0.5 mm in diameter. The middle layers are usually sprinkled with roller grids. The cover layers are usually produced by means of classifying windscrap chambers and use particles which are larger than dust but smaller than the chips for the middle layer. The produced grit mat is finally pressed in a press to a chipboard. A commercially available chipboard has a density of on average 650 to 700 kg / m ³ and knows test and certification procedures to maintain a comparable quality in the competition.

So far, the chips required for the high quality requirements of the chipboard have been obtained by means of knife shaft chippers made of selected round wood to a predominant proportion of over 70%. This shredder is fed a bundle or individual logs and a coplanar arranged to the round wood blades carrying the knife shaft is moved through the round wood and thus produce high quality chips. In addition to the high-quality chips from this production, a chipboard manufacturer can of course also be supplied with other wood materials, such as fresh wood, which is not suitable for cutting in the knife shaft chipper because it is too large, too short, too small in diameter, too odd or similar. In addition, there are other materials such as old wood, rinds, waste, and of course sawdust and sawdust.

• F1: Staub, wird ausgeschleust und meist energetisch verwertet;
• F2: Späne für die Deckschicht (F1<F2<F3);
• F3: Späne für die Mittelschicht, im Durchschnitt 15-30 mm lang und im ∅ 0,5 mm
• F4: Übergroße Späne (i.d.R. abgesiebt mit Maschenweite 12×12 mm)

According to the state of the art, the chips are sieved and used according to the following fractions:

• F1: Dust, is discharged and used mostly energetically;
• F2: chips for the top layer (F1 <F2 <F3);
• F3: chips for the middle layer, on average 15-30 mm long and in ∅ 0.5 mm
• F4: oversized chips (usually screened with mesh size 12 × 12 mm)

Normally, chips do not produce enough small particles for the fraction F2 the outer layers, so that these from oversized chips of the fraction F4 are produced, which were sieved during sieving and post-grinding. The need for post-ground chips for the fraction F2 usually depends on the thickness of the grit mat / material plate to be produced. Thinner material plates require in relation to the fraction F3 the middle layer more re-ground chips for the top layer F2 ,

Irrespective of this, the chips are still screened for foreign bodies and mineral contents in an air separator. In order to increase the selectivity for the sighting can be provided to perform this for each fraction in a separate classifier.

The current opinion of experts is that no more than 30% of chips from other manufacturing processes than the Messerwellenzerspanern may be used in a middle class to achieve the necessary test results for the approval of a standard chipboard. These other chips have on average not the dimensions for standard chips as described above.

However, it is economically disadvantageous that only 30% alternative sources can be used and thus the chipboard production is quite expensive and expensive. It also requires in the environment of the producing plant a sufficient source of logs of the required quality.

Furthermore, it is in the course of economy and ecology advantage if chipboard despite lower wood content and thus lower density yet the necessary properties of conventional Particleboard meet, but are cheaper to produce.

Proceeding from this, the present invention has for its object to provide a comparison with the prior art suitable manufacturing method and a system, with the above-mentioned disadvantages can be avoided. In particular, it should be provided that the raw density of the material plate can be lowered with the new production method, and yet the usual testing and certification procedures for particle board can be successfully completed.

The invention is based on a method for producing a multilayer chipboard with outer layers which are thinner compared to the middle layer, with glued and preferably dried chips being used for scattering the middle layer, the chips being screened in at least one screening device and in at least four fractions F1 . F2 . F3 . F4 be divided ascending grain size, based on the grain size, the first fraction F1 excluded from the production process with the smallest particle size, the second fraction F2 with a larger grain size for the scattering of the outer layers, the next largest third fraction F3 essentially for producing the middle layers and the largest fourth fraction F4 intended for post-shredding.

The solution to the procedure is that the third fraction F3 in two sub-fractions F3a . F3b is split, with the first sub-fraction F3a with the smaller grain size of a post-shredding and then the second fraction F2 for use in the cover layers and the second fraction F3b is used with the larger grain size for the preparation of the middle layer.

With the invention are achieved in an advantageous manner that no longer large-scale chips must be ground to cover layer material, but from the outset in their grain size smaller fraction is converted into cover layer particles whereby the energy input and wear in the overall system is reduced. At the same time, a chipboard can be produced which has larger chips in the middle layer and fulfills the specifications for a conventional chipboard with a smaller proportion of material.

It is preferably provided that for the chips of the middle layer respectively the second sub-fraction F3b larger grain size predominantly chips of 30 - 55 mm in length and 0.7 - 0.8 mm thickness are sieved. Other swarf sources may also be used as the knife-shaft chipper, since the alternative screening and, in particular, the use of larger swarf can produce an equivalent chipboard.

Alternatively or cumulatively, the fourth fraction F4 after re-crushing the sieve again S be supplied. The large-sized chips are accordingly not reground as much as known from the prior art and can be fed back to the screening device and in parts in the other fractions F2 . F3a . F3b be used.

Alternatively or cumulatively, the first fraction may F3a with the smaller grain size after comminution prior to transfer to the second fraction F2 is sieved again or the screening device S be supplied. Here, material can be prevented in an advantageous manner that material that is too small reaches unnecessarily or uncomminuted material in the covering layer.

• Alternativ oder kumulativ kann die zweite Fraktion F2 durch einen Sieb S2 mit einer Maschenweite von 0,2 × 0,2 mm zurückgehalten werden wobei die erste Fraktion F1 durch das Sieb S2 hindurchfällt.
• Alternativ oder kumulativ kann die erste Teilfraktion F3a durch einen Sieb S3a mit einer Maschenweite von 1,4 × 1,4 mm zurückgehalten werden.
• Alternativ oder kumulativ kann die zweite Teilfraktion F3b durch einen Sieb S3b mit einer Maschenweite von 2,5 × 2,5 mm zurückgehalten werden.
• Alternativ oder kumulativ kann die vierte Fraktion F4 durch einen Sieb S4 mit einer Maschenweite von 20 × 20 mm zurückgehalten werden.

The following values for the sieves are preferred embodiments and can be used alone or in combination:

• Alternatively or cumulatively, the second fraction F2 through a sieve S2 with a mesh size of 0.2 × 0.2 mm, with the first fraction F1 through the sieve S2 fall through.
• Alternatively or cumulatively, the first fraction may F3a through a sieve S3a with a mesh size of 1.4 × 1.4 mm are retained.
• Alternatively or cumulatively, the second sub-fraction F3b through a sieve s3b With a mesh size of 2.5 × 2.5 mm are retained.
• Alternatively or cumulatively, the fourth fraction F4 through a sieve S4 retained with a mesh size of 20 × 20 mm.

Alternatively or cumulatively, the chips to be screened may consist predominantly of chips of a length of 40 mm to 70 mm, preferably of a length of 55 mm to 70 mm. You may prefer in a knife ring chipper MRZ have been produced.

The appropriate fractions are sprinkled to a grit mat and pressed to a at least three-layer chipboard a density of less than 650 kg / m ³ , preferably less than 640 kg / m ³ , most preferably less than 630 kg / m ³ .

A low-density chipboard produced by this method meets in a comparative test the strength values of a 650kg / m ³ chipboard.

The solution for a plant for producing a multilayer chipboard with outer and with respect to the middle layer thinner cover layers comprises: a sieve device S , two scatter heads DS for the cover layers, at least one scattering head MS for the middle class, an endlessly circulating form band F for transporting an at least three-layer grit mat SGM and a press P for pressing the spreading material mat SGM in a chipboard SP , wherein at least one screening device S for the production of at least four fractions F1 . F2 . F3 . F4 Ascending grain size is arranged, with the Siebaustrag SF1 for the first fraction F1 with the smallest grain size with a storage bunker VF1 .
the Siebaustrag SF2 for the second fraction F2 with a larger grain size with a spreading head DS for the top layer,
the Siebaustrag SF3a the next larger fraction F3a via a first device ZV1 for post-shredding with a spreading head DS for the cover layer or the screening device,
the Siebaustrag SF3b the next larger fraction F3b with a scattering head MS for the middle class and
the Siebaustrag SF4 the largest faction F4 with a second device ZV2 is operatively connected to the post-shredding.

Preferably, the discharge of the second device ZV2 for the regrinding of the fourth fraction F4 with the entry of the screening device S be actively connected.

Alternatively or cumulatively, between the first device VZ1 and the transfer point to the second fraction F2 respectively the scattering head DS be arranged for the cover layer, a sieve.

Alternatively or cumulatively, it may be for the retention of the second fraction F2 and screening the first fraction S1 a sieve S2 be arranged with a mesh size of 0.2 × 0.2 mm.

Alternatively or cumulatively, the retention of the first partial fraction F3a a sieve S3a be arranged with a mesh size of 1.4 × 1.4 mm.

Alternatively or cumulatively, for the retention of the second fraction F3b a sieve s3b be arranged with a mesh size of 2.5 × 2.5 mm.

Alternatively or cumulatively, the fourth fraction may be retained F4 a sieve S4 be arranged with a mesh size of 20 × 20 mm.

The invention means "operatively connected" that the material flows also arrive via detours, for example conveying devices, bunkers, metering devices, further devices for treating the fraction, in particular re-screening or the like, finally in a substantial proportion of the original amount in the part of the plant, they are intended for.

The screening is realized in the present development substantially in a single screening device. It can be assumed that a repeated sieving with different sieves and essentially similar material flows respectively the corresponding use of the fractions also belongs to the protection handling.

In a preferred variant, the distance of the mesh sizes between the wire is compared to the prior art S3 and S4 significantly enlarged.

Advantageous embodiments and developments, which can be used individually or in combination with each other, are the subject of the dependent claims.

Further advantages of the invention will be described below with reference to embodiments and in conjunction with the drawings.

• 1 eine schematische und nicht umfassende Darstellung einer Anlage zur Herstellung einer Spanplatte von der Holzaufbereitung bis zur Presse nach dem Stand der Technik;
• 2. die erfindungsgemäße Anlage zur Herstellung einer Spanplatte,
• 3 schematische und vereinfachte Darstellung einer vorteilhaften Siebvorrichtung mit Angabe der bevorzugten Maschenweite der Siebe.

In it show schematically:

• 1 a schematic and non-comprehensive illustration of a plant for the production of a chipboard from the wood processing to the press according to the prior art;
• 2 , the plant according to the invention for producing a chipboard,
• 3 schematic and simplified representation of an advantageous screening device with indication of the preferred mesh size of the sieves.

1 shows a schematic and non-comprehensive illustration of a plant for producing a chipboard SP from the wood processing to the press P According to the state of the art. In the prior art, wood is processed into chips and fed to a dryer for drying. Wet wood is usually poorer in screening, so screening before drying does not normally take place. An example is a treatment with a hacker H for the production of wood chips and a subsequent Messerringzerspaner MRZ shown. This preparation normally supports chip production by means of a knife shaft chipper MWZ. After the dryer T The chips arrive in a single screening device S which are usually four fractions F1 . F2 . F3 . F4 the numbering is to reflect the classification from the smallest to the largest grain size or distribution.

The faction F1 , usually dust, becomes a thermal recovery V handed over or otherwise disposed of. She can do that in a storage bunker VF1 be stored.

The next largest fraction F2 , larger in terms of larger grain size, is the scattering heads DS for the production of cover layers of the spreading material mat SGM on the form band F fed.

The next largest fraction F3 will one or more scatter heads MS for producing the middle layer on the forming belt F supplied, wherein the scattering head MS between the scattering heads DS above the form band F is arranged. After scattering of all three layers is the Stgreugutmatte SGM a press P , in the example of a continuous double belt press, fed and there to a chipboard SP pressed.

As a rule, the material flow of the second fraction F2 is insufficient for the top layers, the largest fraction F4 after the screening device S a device ZV2 supplied for comminution. After comminution to a usable particle size distribution in the cover layer, the particles of the fraction F2 added and used in the topcoat. It may be before handing over to the faction F2 a sieve be provided to separate non-crushed material or dust and according to the classification to the other fractions feed or crush again.

2 now shows a plant according to the invention and a corresponding method for the production of particle board SP , The chips in front of the dryer are preferably only with a Messerringzerspaner MRZ prepared and a dryer T fed. As in the prior art material such as sawdust or the like can directly to the dryer here T be supplied. Subsequently, a multi-stage screening device S - Alternatively, several screening devices - provided the chips in five fractions F1 . F2 . F3a . F3b and F4 split. In contrast to 1 and the prior art becomes the original third fraction F3 in two sub-fractions F3a and F3b divided up.

In a preferred and independent embodiment, the distance of the mesh sizes between the sieve S3 and S4 is significantly increased compared to the prior art, since the sieve S4 usually has a mesh size of 12 × 12mm according to the prior art.

In a further preferred and independent embodiment, the fraction F4 not directly on a size of the faction F2 or F1 regrind, but only so reduced that this in the screening device S can be recycled via a Siebeintrag SE and is classified there again.

The sub-fraction F3a after a post-shredding in a device ZV1 and the faction F2 are merged and in the scattering heads DS for the cover layers for the production of the spreading material mat SGM on the form band F used. Only the sub-fraction F3b is in the scattering head MS used for the middle class.

In a further preferred and independent embodiment, these chips are the fraction F3b longer than in the prior art, with appropriate Siebauswahl.

In a further preferred and independent embodiment shows 3 a possible sieve construction with possible mesh sizes of the sieves S2 . S3a . s3b and S4 and the emergence of the corresponding fractions from the seven.

LIST OF REFERENCE NUMBERS

DS

Spreading head (covering layer)

F

forming belt

F1

Group (first)

F2

Group (second)

F3

Group (third)

F3a

Partial fraction (first)

F3b

Partial fraction (second)

F4

fraction

H

hacker

MS

Scattering head (middle layer)

MRZ

Knife ring

P

Press

S

screening device

S2

scree

S3a

scree

s3b

scree

S4

scree

SF1

Siebaustrag

SF2

Siebaustrag

SF3

Siebaustrag

SF3a

Siebaustrag

SF3b

Siebaustrag

SF4

Siebaustrag

SGM

grit mat

SP

chipboard

T

dryer

VF1

Storage bunker (Fraction 1)

ZV1

Device (for shredding)

ZV2

Device (for shredding)

Claims (18)

Process for the production of a multilayer chipboard with outer layers which are thinner and thinner than the middle layer, using glued and preferably dried chips for scattering the middle layer, the chips being screened in at least one screening device (S) and split into at least four fractions (F1, F2, F3 , F4) are divided with increasing grain size, wherein based on the grain size, the first fraction (F1) with the smallest grain size excluded from the process for the production, the second fraction (F2) with a larger grain size for scattering of the outer layers, the next largest third fraction (F3) is essentially provided for the production of the middle layers and the largest fourth fraction (F4) for post-comminution, characterized in that the third fraction (F3) is divided into two sub-fractions (F3a, F3b), wherein the first fraction fraction (F3a) with the smaller grain size of a post-shredding and then the second fraction (F2) is fed for use in the cover layers and the second fraction (F3b) with the larger grain size is used to produce the middle layer. Method according to Claim 1 , characterized in that for the chips of the middle layer respectively the second sub-fraction (F3b) larger grain size predominantly chips of 30 - 55 mm in length and 0.7 - 0.8 mm thickness are screened. Method according to Claim 1 or 2 , characterized in that the fourth fraction (F4) after re-crushing the sieve device (S) is supplied. Method according to one of the preceding claims, characterized in that the first part fraction (F3a) with the smaller grain size before being transferred to the second fraction (F2) is screened again or the screening device (S) is supplied. Method according to one of the preceding claims, characterized in that the second fraction (F2) is retained by sieve (S2) with a mesh size of 0.2 × 0.2 mm and the first fraction (F1) falls through. Method according to one of the preceding claims, characterized in that the first part fraction (F3a) is retained by sieve (S3a) with a mesh size of 1.4 × 1.4 mm. Method according to one of the preceding claims, characterized in that the second sub-fraction (F3b) is retained by sieve (S3b) with a mesh size of 2.5 × 2.5 mm. Method according to one of the preceding claims, characterized in that the fourth fraction (F4) is retained by sieve (S4) with a mesh size of 20 × 20 mm. Method according to one of the preceding claims, characterized in that the chips to be screened predominantly from wood chips of a length of 40 mm to 70 mm, preferably a length of 55 mm to 70 mm, and most preferably in a Messerringzerspaner (MRZ) are produced. Method according to one of the preceding claims, characterized in that a three-layer chipboard (SP) a density of less than 650 kg / m ³ , preferably less than 640 kg / m ³ , most preferably less than 630 kg / m ³ , is produced. Method according to Claim 10 , characterized in that the low density chipboard in a comparative test, the strength values of a 650kg / m ³ chipboard. Plant for producing a multilayer chipboard with outer layers which are thinner relative to the middle layer and comprising a sieving device (S), two scattering heads (DS) for the cover layers, at least one scattering head (MS) for the middle layer, an endlessly circulating forming belt (F) for transporting one at least three-layer spreading material mat (SGM) and a press (P) for pressing the spreading material mat (SGM) into a chipboard (SP), wherein at least one screening device (S) for producing at least four fractions (F1, F2, F3, F4) of increasing grain size is arranged, wherein the Siebaustrag (SF1) for the first fraction (F1) with the smallest grain size with a storage bunker (VF1), the Siebaustrag (SF2) for the second fraction (F2) with a larger grain size with a scattering head (DS) for the top layer, the Siebaustrag (SF3a) of the next largest fraction fraction (F3a) via a first device (ZV1) for post-shredding with a scattering head (DS) f for the top layer or the screening device (S), the sieve support (SF3b) of the next largest fraction (F3b) with a middle layer (MS) spreading head (MS) the sieve structure (SF4) of the largest fraction (F4) is operatively connected to a second device (ZV2) for post-shredding. Plant according to the previous plant claim, characterized in that the discharge of the second device (ZV2) for post-shredding the fourth fraction (F4) with the entry of the screening device (S) is operatively connected. Installation according to one of the preceding system claims, characterized in that between the first device (VZ1) and the transfer point to the second fraction (F2) and the scattering head (DS) for the cover layer, a sieve is arranged. Plant according to one of the preceding claims, characterized in that for the retention of the second fraction (F2) and screening of the first fraction (S1) a sieve (S2) with a mesh size of 0.2 × 0.2 mm is arranged. Plant according to one of the preceding claims, characterized in that for the retention of the first fraction (F3a) a sieve (S3a) with a mesh size of 1.4 × 1.4 mm is arranged. Plant according to one of the preceding claims, characterized in that for the retention of the second fraction (F3b) a sieve (S3b) with a mesh size of 2.5 × 2.5 mm is arranged Installation according to one of the preceding claims, characterized in that for the retention of the fourth fraction (F4) a sieve (S4) with a mesh size of 20 × 20 mm is arranged.

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