EP4378650A1 - Method for producing osb and osb production device - Google Patents

Abstract

The invention relates to a method for producing OSB with the steps: producing coarse chips, applying glue to the coarse chips so that glued coarse chips are produced, arranging the glued coarse chips on a conveyor belt so that a chip layer is produced, applying a flame retardant liquid to the chip layer and pressing the chip layer so that the OSB is produced.

Description

The invention relates to a method for producing, in particular, flame-retardant OSB (oriented strand board), which can also be referred to as chipboard.

According to a second aspect, the invention relates to an OSB manufacturing device with (a) a coarse chip manufacturing device for producing coarse chips from wood, (b) a dryer for drying the coarse chips, which is connected to the coarse chip manufacturing device, (c) a belt conveyor arranged behind the dryer in the material flow direction, (d) a first distribution device for distributing coarse chips on the belt conveyor so that a first cover layer is formed, (e) a second distribution device for distributing coarse chips so that a second cover layer is formed above the first cover layer so that a chip layer is formed, and (d) a press for pressing the chip layer into an OSB board. The OSB manufacturing device can also be referred to as a coarse chipboard manufacturing device.

It is beneficial to use as little flame retardant as possible when producing flame-retardant OSB, as this is very costly. One reason for this is that flame retardants themselves are expensive. In addition, flame retardants mean that more glue has to be used to achieve the same mechanical strength as a non-flame-retardant OSB board, which is also undesirable. In addition, most flame retardants are poorly soluble in water, so that introducing the flame retardant into the chips also introduces large amounts of water, which often have to be removed during further processing.

The invention is based on the object of improving the production of flame-retardant wood-based panels, in particular OSB.

The invention solves the problem by a method for producing OSB with the steps (a) producing coarse chips, (b) applying glue to the coarse chips so that glued coarse chips are formed, (c) arranging the glued coarse chips on a conveyor belt so that a chip layer is formed, (d) applying a flame retardant liquid to this chip layer and (e) pressing the chip layer so that the OSB board is formed.

In its most general form, the invention solves the problem of a method for producing wood-based panels with the steps (a) producing chips, (b) applying glue to the chips so that glued chips are produced, (c) arranging the glued chips on a conveyor belt so that a chip layer is produced, (d) applying a flame retardant liquid to this chip layer and (e) pressing the chip layer so that the wood-based panel is produced. When coarse chips are mentioned below, normal chips that are not coarse chips are also meant within the scope of this most general form of the invention.

According to a second aspect, the invention solves the problem by a generic OSB manufacturing device which has (a) a first flame retardant liquid application device which is arranged to apply a flame retardant liquid to the first cover layer, and (b) a second flame retardant liquid application device which is arranged to apply a flame retardant liquid to the second cover layer.

In its most general form, the invention solves the problem by a wood-based panel manufacturing device with (a) a chip manufacturing device for producing chips from wood, (b) a dryer for drying the chips, which is connected to the coarse chip manufacturing device, (c) a belt conveyor arranged behind the dryer in the material flow direction, (d) a first distribution device for distributing chips on the belt conveyor so that a first cover layer is formed, (e) a second distribution device for distributing chips so that a second cover layer is formed above the first cover layer so that a chip layer is formed (d) a press for pressing the chip layer into an OSB board, (e) a first flame retardant liquid application device arranged to apply a flame retardant liquid to the first cover layer, and (d) a second flame retardant liquid application device, which is arranged to apply a flame retardant liquid to the second cover layer. When OSB is mentioned below, wood-based panels are generally meant within the scope of this most general form of the invention; when a coarse chip production device is mentioned, a chip production device is generally meant.

The first flame retardant liquid application device is preferably arranged in the material flow direction upstream of the second flame retardant liquid application device and/or upstream of the second distribution device.

The advantage of the invention is that - compared to spraying the flame retardant liquid into a mixer - there are generally fewer spray losses. In addition, there is generally no loss of flame retardant due to chips rubbing against each other or against components of the OSB production device.

It is also advantageous that there only needs to be a small distance between the place where the flame retardant liquid is applied and a press for pressing the chip layer. According to a preferred embodiment, this distance is less than 30 m. This reduces the amount of OSB that has a sufficiently high flame retardant content, particularly when starting up or changing to the production of flame-retardant OSB. In this way, flame-retardant OSB and non-OSB can also be produced using the same OSB production device. Furthermore, the reaction time between glue and flame retardant or the water in the flame retardant is shortened.

In the context of the present description, coarse chips are understood to mean in particular wood chips which are in the size range 200±30 cm x 20±4 cm x 0.5±0.2 cm.

In particular, the method according to the invention is a method for producing flame-retardant OSB according to DIN EN 13823 (single burner item) or flame-retardant OSB according to DIN EN 13501-1.

The flame retardant liquid is preferably an aqueous solution. The flame retardant liquid preferably contains at least one organic or inorganic phosphorus-containing and/or nitrogen-containing compound. The flame retardant is preferably boron-free.

Pressing the chip layer is understood in particular to mean that at least the coarse chips are pressed. In particular, it is possible that additional chips that are not coarse chips are pressed with the coarse chips. It is also possible and represents a preferred embodiment that a first cover layer and a second cover layer are scattered from the coarse chips and pressed with a middle layer that is arranged between the two cover layers to form the OSB.

Pressing is understood to mean pressing using a belt press. In other words, the press is preferably a belt press.

The flame retardant liquid is understood to mean in particular a solution, emulsion or dispersion which contains flame retardants in a liquid phase, in particular a solvent.

The application of the flame retardant liquid to the coarse chips is understood in particular to mean spraying, pouring or jetting.

The distribution of coarse chips on the belt conveyor is understood in particular to mean the distribution of the coarse chips on a conveyor belt of the belt conveyor.

The feature that the second flame retardant liquid application device is arranged to apply a flame retardant liquid to the second cover layer is understood in particular to mean that the flame retardant is applied in such a way that it wets the second cover layer, but preferably not the first cover layer or any middle layer that may be present. In particular, application to the cover layer does not just mean application above the cover layer.

A conveyor belt is understood to be a flexible component for endless conveying. It is possible, but not necessary, for the conveyor belt to be made of metal, a mesh structure, a textile or an entropy-elastic material, such as rubber.

The term is used as a generic term for top layer, middle layer and chip layer.

A chip layer is a layer made of chips. This can be the top layer, the middle layer or the chip layer, but also two or three of these layers or possibly further layers made of chips.

According to a preferred embodiment, the method comprises the step of drying the coarse chips before applying the glue. By first applying the glue to the coarse chips and then applying the flame retardant, the losses of flame retardant, in particular through abrasion, are reduced.

According to a preferred embodiment, the method comprises the steps (a) producing top chips, in particular in the form of coarse chips, and middle layer chips, (b) optionally drying, in particular drying together, the coarse chips and middle layer chips, (c) optionally separating coarse chips and middle layer chips, in particular dried coarse chips and middle layer chips (d) producing a first top layer from coarse chips, (e) applying the flame retardant liquid to the top layer (f) producing a middle layer above the top layer from middle layer chips, (g) producing a second top layer from top chips above the middle layer so that the chip layer is created and (h) applying the flame retardant liquid to the second top layer. Preferably, the first top layer, the second top layer and the middle layer, which form a chip layer, are then pressed to form OSB.

It is possible, but not necessary, that the middle layer chips are also coarse chips. In particular, it is possible that the middle layer chips have a length distribution density, whereby the length distribution density indicates the number of coarse chips with a certain length. The length distribution density preferably has a middle layer chip length median that is smaller than a top layer chip length median of the length distribution density of the top chips. In other words, the chips that form the top layers are longer than the chips that form the middle layer.

It is possible, but not necessary, that flame retardant liquid is also applied to the middle layer. In particular, no flame retardant liquid is applied to the middle layer. In this case, the flame retardant is concentrated in the outer layers, which results in particularly high flame retardancy while at the same time the OSB has a low flame retardant content.

Preferably, the method comprises the steps of (a) detecting a moisture content of the OSB and/or the chip layer after application of the flame retardant and (b) changing an application amount of flame retardant liquid and/or a flame retardant concentration of flame retardant in the flame retardant liquid so that the chip layer moisture content is within a predetermined target moisture content interval and a flame retardant content of the chip layer and/or the OSB is within a predetermined target flame retardant content interval.

In particular, the method preferably comprises the steps of (a) detecting a top layer moisture content of the first top layer and/or the second top layer after application of the flame retardant and (b) changing the application amount of flame retardant liquid and/or the flame retardant concentration of the flame retardant in the flame retardant liquid so that the top layer moisture content lies in a predetermined target top layer moisture content interval.

The reduction of the flame retardant concentration is carried out, for example, by adding solvent, in particular water, to the flame retardant liquid. The increase of the flame retardant concentration is carried out, for example, by reducing the addition of solvent. Alternatively, the increase of the flame retardant concentration can comprise increasing the temperature of the flame retardant liquid if - as according to a preferred embodiment intended - the flame retardant is present at its saturation concentration in the flame retardant liquid. For example, the solvent is passed through a bath of solid flame retardant. The higher the temperature of the solvent, the higher the flame retardant concentration.

The chip layer has a chip layer temperature, the top layer has a top layer temperature and the middle layer has a middle layer temperature. These temperatures refer to a position in the direction of material flow immediately before the point where the flame retardant liquid is applied. In each case, they are the average temperature over the full width of the respective layer.

Preferably, the temperature of the flame retardant liquid and the flame retardant concentration are selected such that cooling the flame retardant liquid to the respective temperature (chip layer temperature, top layer temperature or middle layer temperature) results in the flame retardant content at this temperature being below the solubility of the flame retardant. In this way, little solvent is introduced into the corresponding layer.

When applied to the respective layer, the flame retardant liquid preferably has a temperature of at least 50°C, in particular at least 60°C, preferably 70°C, particularly preferably at least 80°C. A high temperature generally increases the solubility of the flame retardant in the solvent, so that less solvent, usually water, is required to dissolve a given amount of flame retardant. In addition, the viscosity of water decreases with increasing temperature, so that the flame retardant liquid can penetrate the coarse chips more easily.

It is advantageous if the flame retardant liquid contains a concentration of flame retardant that corresponds to at least 60%, in particular at least 70%, preferably at least 80%, particularly preferably at least 90%, of the maximum solubility of the flame retardant at the corresponding temperature. A further advantage is that the heated flame retardant causes the two cover layers to experience a temperature increase, which enables a higher press speed.

It is advantageous if the flame retardant liquid contains a viscosity reducer, in particular a surfactant. This allows the flame retardant liquid and thus the flame retardant to penetrate the chips more quickly. The flame retardant liquid preferably contains a viscosity reducer.

It is advantageous if the method comprises the step of applying a pressure difference to the chip layer, cover layer or middle layer that is or will be wetted with flame retardant liquid. The application of the pressure difference can comprise applying a negative pressure, in particular to an underside of the belt conveyor on an upper side of the chip layer, cover layer or middle layer.

The advantage of this is that the consumption of flame retardants can generally be reduced compared to conventionally produced OSB. By applying a pressure difference to the coarse chips, the flame retardant liquid is at least partially absorbed into the coarse chips. This means that there is less of a crust of flame retardants forming on the coarse chips. If the flame retardant at least partially penetrates the coarse chips, its effectiveness is increased.

By sucking and/or pressing the flame retardant liquid into the coarse chips, there are often fewer chemical reactions with the glue. As a rule, the amount of glue therefore needs to be increased significantly less to compensate for a loss of strength caused by the addition of the flame retardant.

The creation of the pressure difference by applying excess pressure is understood in particular to mean that a pressure difference is generated between a first side surface of the coarse chips and the opposite side surface of the coarse chips. The two side surfaces are spaced apart by the height of the coarse chips, which is preferably 0.5 ± 0.2 cm.

The application of the pressure difference by applying negative pressure is understood in particular to mean that a pressure is applied to the coarse chips, in particular to the covering layer, which is at least 200 hPa, preferably at least 400 hPa, particularly preferably at least 600 hPa, lower than the ambient pressure.

Gluing is preferably carried out without a pressure difference applied to the coarse chips.

Preferably, the negative pressure is applied to the underside of a conveyor belt of the belt conveyor. The conveyor belt is gas-permeable for this purpose. For example, the conveyor belt is perforated or made of a gas-permeable material, such as a textile. Alternatively, the conveyor belt can be a metal belt. This metal belt is preferably perforated.

The overpressure is applied, for example, by the layer first passing a roller that acts as a seal and then entering an overpressure area in which the overpressure is present. The layer lies on a gas-permeable conveyor belt, on the side of which facing away from the overpressure area there is a lower pressure, for example ambient pressure or negative pressure. The layer leaves the overpressure area by passing a roller that acts as a seal.

Preferably, the coarse chips are dried until they are kiln-dry. In this state, flame retardant liquid is absorbed particularly easily and quickly by the dried coarse chips. According to a preferred embodiment, the coarse chips containing flame retardant are not dried significantly. This is to be understood in particular that the moisture content of the respective layer (top layer, middle layer or chip layer) changes by a maximum of five percentage points, in particular by a maximum of two percentage points, after the flame retardant liquid has been applied.

Preferably, the coarse chip layer has a chip layer thickness that is at most four times, preferably at most three times, preferably at most twice, the thickness of a coarse chip layer of a single coarse chip layer. The coarse chip layer thickness is the minimum achievable thickness of a coarse chip layer. This is the average height of an arrangement of coarse chips on a flat, horizontal test surface of 1 m ² , whereby for this arrangement, the following applies: on a maximum of 75% of the test area has sections of two or more coarse chips lying on top of each other and at least 90%, preferably at least 95%, in particular 100%, of the test area being covered by coarse chips.

The flame retardant liquid preferably contains a dye. This dye is preferably colorless in the visible range. In this case, the dye can also be referred to as a marker. It is advantageous if the dye absorbs and/or fluoresces in the UV range. In this case, a flame retardant distribution of the flame retardant liquid and/or the flame retardant can be recorded by irradiating with UV light and/or taking an image of the respective layer and/or the OSB board with a camera sensitive to the UV range.

According to a preferred embodiment, a process parameter in the form of the conveyor belt speed and/or the pressure difference and/or an area-specific application rate of flame retardant liquid is regulated based on the flame retardant distribution. In other words, a deviation between a target flame retardant distribution and the respective measured actual flame retardant distribution is determined and at least one of the parameters mentioned is regulated so that the deviation is minimized.

An OSB manufacturing device according to the invention preferably has a third distribution device for distributing chips so that a middle layer is created above the first cover layer. In particular, the third distribution device is designed so that the middle layer lies on the first cover layer. The second distribution device is then preferably designed so that the second cover layer lies on the middle layer. Accordingly, the second distribution device is preferably arranged behind the third distribution device in the direction of material flow.

The OSB production device preferably has a hopper which is arranged in the material flow direction behind the coarse chip production device and preferably behind a dryer for the coarse chips. The hopper is preferably arranged in the material flow direction before the distribution devices. In other words The distribution devices distribute glued chips. The hopper is preferably a rotating gluing drum or a mixer, in particular a trough mixer.

The OSB production device preferably has a classifier for separating top layer chips and middle layer chips. The classifier is preferably a sifter. It is advantageous if the classifier is arranged behind the coarse chip production device and/or in front of the bucket in the direction of material flow.

The pressure difference generator for applying the pressure difference to the chip layer preferably comprises a vacuum generator and/or a pressure generator. The differential pressure generator preferably has a vacuum pump and at least one suction chamber, preferably at least two suction chambers, in particular a plurality of suction chambers, each of which is connected to the vacuum pump via a valve. The valves are preferably designed to increase their valve opening degree as the pressure in the suction chamber decreases. In other words, the valves open further the lower the pressure in the respective suction chamber.

The suction chambers are arranged in particular in such a way that at least 90% of the surface, preferably at least 95% of the surface, particularly preferably 100% of the surface of the coarse chipping system can be subjected to the pressure difference, in the present case to a negative pressure, for at least a predetermined time of, for example, 1 second, in particular at least 5 seconds, by means of at least one suction chamber.

Preferably, a negative pressure is at least 300 hPa (and the pressure is therefore 713 hPa), in particular at least 500 hPa (and the pressure is therefore 513 hPa).

It is advantageous if the OSB manufacturing device has an inspection system for detecting the flame retardant distribution in the respective layer. This can be the distribution of the flame retardant in the surface of the coarse chip layer, i.e. the two-dimensional distribution in the length and width direction of the coarse chip layer, but not in the thickness direction.

Alternatively or additionally, the inspection system can be designed to detect the flame retardant distribution in the OSB. This can then be the distribution of the flame retardant in the surface of the OSB, i.e. the two-dimensional distribution in the longitudinal direction and width direction of the coarse chip layer, and/or the distribution of the flame retardant in the thickness direction.

The inspection system preferably has a camera for capturing UV light and/or fluorescent light that is generated when the coarse chip layer or the OSB is irradiated with UV light. The inspection system preferably also has a UV light source for irradiating the coarse chip layer or the OSB with UV light.

The OSB production device preferably comprises a moisture meter for measuring a moisture content of a chip layer, in particular the first cover layer and/or the second cover layer. The moisture meter is preferably designed for spatially resolved measurement of the moisture content of the chip layer. This moisture meter can, for example, comprise an infrared light source and an infrared camera. The infrared light source is preferably designed to emit infrared radiation with a wavelength of 3±0.5 µm. In this wavelength range, water absorbs the infrared light particularly strongly and reflects it correspondingly very little.

Particularly preferably, the OSB production device has a control system which is designed to automatically control the first flame retardant liquid application device and/or the second flame retardant liquid application device to change an application amount of flame retardant liquid and/or a concentration of the flame retardant, so that the chip layer moisture content is in a predetermined target moisture content interval and a flame retardant content of the chip layer and/or the OSB is in a predetermined target flame retardant content interval.

It is advantageous if at least one of the flame retardant liquid application devices has at least two, in particular a plurality of, nozzles that can be individually controlled by the control system. The control system is then designed to control the nozzles of the flame retardant liquid application device so that the actual spatial distribution of the flame retardant is limited by a predetermined Target distribution, in particular a spatially constant concentration of flame retardant, deviates as little as possible.

The flame retardant liquid application device preferably comprises a temperature control which is designed to automatically set a target temperature and/or a concentration control for setting a target concentration of flame retardant in the solvent. The solvent is preferably water. The saturation concentration of the flame retardant in the water can be set by the temperature. If - as provided according to a preferred embodiment - the flame retardant application device is set up to apply a flame retardant liquid whose concentration of flame retardant corresponds to the saturation limit, the concentration of flame retardant can be increased by increasing the temperature.

Figur 1

ein Flussdiagramm eines erfindungsgemäßen Verfahrens und

Figur 2

eine schematische Ansicht einer erfindungsgemäßen OSB-Herstellvorrichtung zum Durchführen eines erfindungsgemäßen Verfahrens.

The invention is explained in more detail below with reference to the accompanying drawings.

Figure 1

a flow chart of a method according to the invention and

Figure 2

a schematic view of an OSB manufacturing device according to the invention for carrying out a method according to the invention.

Figure 1 shows schematically a wood-based panel manufacturing device according to the invention, here in the form of an OSB manufacturing device 10, which has a chip manufacturing device, here in the form of a coarse chip manufacturing device 12, which first debarks wood 14 in a debarker 16 and then chips it in a chipper 18 to form chips, here in the form of coarse chips 20. The chips 20 are dried in a dryer 22, preferably until they are kiln-dry.

In a classifier 24, which in this case is designed as a sifter, top chips 26 are separated from middle layer chips 28. The middle layer chips are smaller, in particular shorter, than the top chips 26. In the material flow direction M behind the classifier 24 there is a bin 30, for example a rotating gluing drum or a mixer, in particular a trough mixer, which in the present case has a top layer chip gluing unit 30a and a middle layer chip gluing unit 30b, which glue the top chips 26 and the middle layer chips 28 respectively.

Cover chips 26, which can also be referred to as cover layer chips, are scattered by a first distribution device 32.1 to form a first cover layer 34.1. A first flame retardant liquid application device 36.1 is used to apply a schematically drawn flame retardant liquid 38 to the first cover layer 34.

Cover chips 26 are also scattered by a second distribution device 32.2 to form a second cover layer 34.2. A schematically drawn flame retardant liquid 38 is applied to the first cover layer 34 by means of a second flame retardant liquid application device 36.2.

By means of a second flame retardant liquid application device 36.2, a schematically drawn flame retardant liquid 38 is applied to the second cover layer 34.2.

Middle layer chips 38 are spread onto the first cover layer 4 30.1 by means of a third distribution device 32.3, so that they form a middle layer 40. It is possible, but not necessary and in the Figure 1 In the embodiment shown, it is not provided that flame retardant 38 is applied to the middle layer by means of a flame retardant liquid application device.

The first cover layer 34.1, the middle layer 40 and the second cover layer 34.2 together form a chip layer 42, which is pressed into an OSB 46 by means of a hot press 44.

Figure 2 shows a schematic view of the OSB manufacturing device 10 in a side view. The flame retardant liquid application devices 36.1, 36.2 have together or - as in Figure 1 shown - a reservoir 50.1, 50.2 in which the flame retardant liquid 38 is contained. By means of a heater 52.1, 52.2 the flame retardant liquid 38 can be brought to a predetermined temperature T ₂₈ , for which, for example, 50°C ≤ T ₂₈ ≤ 95°C applies.

By means of a metering pump 54.1, the flame retardant liquid 38 is fed to nozzles 56.k (k = 1, 2, ...) of the respective flame retardant liquid application device, in the present case the first flame retardant liquid application device 36.1 (see Figure 3 ), which are arranged next to each other transversely to the material flow direction M, and from there sprayed onto the first cover layer 34.1.

In order to improve the introduction of the flame retardant liquid 38, the OSB production device 10 can have a pressure difference generator 58, which is designed to apply a pressure difference to the first cover layer 34.1. This creates coarse chips 20 containing flame retardant.

How Figure 3 shows, the pressure difference generator 58 has, for example, a vacuum pump 60 which is connected to a plurality of suction chambers 62.j (j = 1, 2, ...). When the vacuum pump 60 is operating, a pressure p _j of, for example, 100 hPa ≤ p _j ≤ 800 hPa is therefore present at the suction chambers 62.j. It is possible that the pressures in the individual suction chambers 62.j differ from one another. Valves not shown can be used for this purpose.

The suction chambers 62.j are located on a conveyor belt 64, in particular a metal belt, of a belt conveyor 66, which has openings, for example holes. As a result, the pressure p _j is applied to the first cover layer 34.1.

A first inspection system 70.1 can be arranged behind the pressure difference generator 58 in the material flow direction M, which has a camera 72.1. The camera 72 detects light that is reflected, emitted and/or not absorbed by a dye in the flame retardant liquid 38. Alternatively or additionally, the camera 72.1 detects fluorescent light. In this way, an actual flame retardant distribution k _ist (x,y) is determined, which indicates a concentration k of flame retardant depending on the area coordinates x, y. Again alternatively or additionally, the camera 72.1 can be used as a moisture meter and measure the moisture distribution in the covering layer 34.1 using reflected or absorbed IR light.

A control 74 compares the actual flame retardant distribution k _ist (x,y) with a target flame retardant distribution k _soll (x,y) and controls the nozzles 56.k individually so that a deviation between the actual flame retardant distribution k _ist (x,y) and the target flame retardant distribution k _soll (x,y) is minimized.

It is possible, but not necessary, for the inspection system to have a UV light source 76.1 that illuminates the cover layer 22 in a field of view G of the camera 72.1. The field of view G is the area of the cover layer 34.1 that is recorded by the camera 72.

Figure 1 shows that - regardless of other features of this embodiment - a cutting device 78 can be arranged behind the hot press 44 in the material flow direction, which cuts the OSB board 46 into individual board segments 80.I. In this case, it is advantageous if a second inspection system 82 (see Figure 3 ), whose camera 84 records a cut surface 86 of the respective plate segment 80.I. From this, a second actual flame retardant distribution k _ist,2 (y,z) is determined, which also encodes the depth dependence of the concentration k of flame retardant. In other words, the second actual flame retardant distribution k _ist,2 (y,z) encodes a depth profile of the dye.

The control 74 is designed to change the pressures p _j in the at least one suction chamber 60.j and/or a conveyor belt speed v ₆₂ of the conveyor belt 62, so that the second actual flame retardant distribution k _ist,2 (y,z) approaches a second target flame retardant distribution k _soll,2 (y,z). <b>List of reference symbols</b> 10 OSB manufacturing device 54 Dosing pump 12 Coarse chip production device 56 jet 14 Wood 58 Pressure difference generator 16 Debarker 18 Machinists 60 Vacuum pump 62 Suction chamber 20 Chips 64 Conveyor belt 22 dryer 66 Belt conveyor 24 Classifier 26 Deck shavings 70 Inspection system 28 Middle layer chips 72 camera 74 regulation 30 Beleimer 76 UV light source 30a Top layer chip gluing unit 78 Cutting device 30b Middle layer chip gluing unit 32.1 first distribution device 80 Plate segment 32.2 second distribution device 82 second inspection system 32.3 third distribution device 84 second camera 34.1 first top layer 86 Cutting surface 34.2 second top layer 36 Flame retardant liquid application device G Facial field j. k, l Running index 38 Flame retardant liquid k _is (x,y) Actual flame retardant distribution 40 Middle class k _should (x,y) Target flame retardant distribution 42 Chip layer 44 Hot press k _is,2 (y,z) second actual flame retardant distribution 46 OSB board k _should,2 (y,z) second target flame retardant distribution 50 reservoir 52 Heating M Material flow direction p Pressure

Claims (15)

Process for producing OSB (46) comprising the steps: (a) Production of coarse chips, (b) Applying glue to the coarse chips to produce glued coarse chips, (c) arranging the glued coarse chips on a conveyor belt (64) so that a chip layer (42) is formed, (d) applying a flame retardant liquid to the chip layer (42) and (e) Pressing the chip layer (42) to form the OSB (46). Method according to claim 1, characterized by the steps: (a) producing top chips (26) in the form of coarse chips and middle layer chips (28), (b) producing a first covering layer (34.1) from covering chips (26), (c) applying the flame retardant liquid to the first topcoat (34.1), (d) producing a middle layer (40) from middle layer chips (28) above the first cover layer (34.1), (e) producing a second cover layer (36.2) from cover chips (26) above the middle layer (40) so that the chip layer (42) is formed, and (f) Applying the flame retardant liquid to the second topcoat (34.2). Method according to one of the preceding claims, characterized by the steps: (a) detecting a particle layer moisture content of the particle layer (42) after application of the flame retardant and/or the OSB (46) and (b) changing an application amount of flame retardant liquid and/or a concentration of the flame retardant so that the particle layer moisture content is within a predetermined target moisture content interval and a flame retardant content of the particle layer (42) and/or the OSB (46) is within a predetermined target flame retardant content interval. Method according to one of the preceding claims, characterized in that the flame retardant liquid (a) when applied to the chip layer (42) has a temperature of at least 50°C and/or (b) contains a viscosity reducer, in particular a surfactant. Method according to one of the preceding claims, characterized by the steps:
Applying a pressure difference to the chip layer (42) wetted or to be wetted with flame retardant liquid by applying
a negative pressure on an underside of the belt conveyor (66) and/or an overpressure on an upper side of the chip layer (42). Method according to one of the preceding claims, characterized in that a chip layer thickness of the chip layer (42) corresponds at most to four times a coarse chip thickness of a coarse chip layer. Method according to one of the preceding claims 2 to 2, characterized in that (a) the flame retardant liquid contains a dye, in particular a colourless dye which absorbs or fluoresces in the UV range, and (b) the method comprises the following steps: (i) depth-dependent, in particular optical, detection of a dye concentration of the chip layer (42) and/or the OSB board (46) so that a dye depth profile is obtained, and (ii) Controlling a conveyor belt speed, the pressure difference and/or an area-specific application rate of flame retardant liquid based on the dye depth profile. OSB manufacturing device (10) with (a) a coarse chip producing device (12) for producing coarse chips from wood (14), (b) a dryer (22) for drying the coarse chips, which is connected to the coarse chip producing device (12), (c) a belt conveyor (66) arranged behind the dryer (22) in the material flow direction (M), (d) a first distribution device (32.1) for distributing coarse chips on the belt conveyor (66) so that a first covering layer (34.1) is formed, (e) a second distribution device (32.2) for distributing coarse chips so that a second covering layer (34.2) is formed above the first covering layer (34.1), so that a chip layer (42) is formed (f) a press for pressing the chip layer (42) into an OSB board (46), marked by (g) a first flame retardant liquid application device arranged to apply a flame retardant liquid to the first cover layer (34.1), and (h) a second flame retardant liquid application device arranged to apply a flame retardant liquid to the second cover layer (34.2). OSB manufacturing device (10) according to claim 8, characterized by a third distribution device (32.3) for distributing chips (20) so that a middle layer (40) is formed above the first cover layer (34.1), wherein the second distribution device (32.2) is arranged behind the third distribution device (32.3) in the material flow direction (M) (second cover layer (34.2) is above the middle layer (40)). OSB manufacturing device (10) according to claim 8 or 9, characterized by (a) a bucket (30) which is arranged in the material flow direction (M) behind the coarse chip production device (12) and in particular behind the dryer (22) and in front of the at least one distribution device (32) and/or (b) a classifier (24) for separating top chips (26) and middle layer chips (28), which is arranged in the material flow direction (M) behind the coarse chip producing device (12) and in front of the bucket (30). OSB manufacturing device (10) according to one of claims 8 to 10, characterized by an inspection system (70) for detecting a flame retardant distribution of flame retardants in the chip layer (42) and/or in the OSB (46). OSB manufacturing device (10) according to claim 9, characterized in that the inspection system (70) (a) a UV light source (76) and (b) camera (72) for detecting reflected UV light and/or fluorescent light. OSB manufacturing device (10) according to one of claims 8 to 12, characterized by (a) a moisture meter for measuring a chip layer moisture content of the chip layer (42), in particular the first cover layer (34.1) and/or the second cover layer (34.2), and (b) a control system (74) which is designed to automatically control the first flame retardant liquid application device and/or the second flame retardant liquid application device to change an application amount of flame retardant liquid and/or a concentration of the flame retardant, so that the chip layer moisture content is in a predetermined target moisture content interval and a flame retardant content of the chip layer (42) and/or the OSB board (46) is in a predetermined target flame retardant content interval. OSB manufacturing device (10) according to claim 9 or 12, characterized by a control (74) which is designed to automatically control a conveyor belt speed, the pressure difference and/or a surface-specific application amount of flame retardant liquid based on the flame retardant distribution. OSB manufacturing device (10) according to one of the preceding claims,
characterized in that
the pressure difference generator (58) (a) a vacuum pump (60) and a plurality of suction chambers (62), each connected to the vacuum pump (60) via a valve,
(wherein the valves have a valve opening degree which increases with decreasing pressure (p) in the suction chambers (62). (b) a pressure pump and a plurality of pressure chambers each connected to the pressure pump (wherein the valves have a valve opening degree which increases with decreasing pressure (p) in the suction chamber (62)).

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