Method for producing oriented strand boards, and oriented strand board production device

Abstract

The invention relates to a method for producing oriented strand boards (44), comprising the steps: producing coarse chips (20); applying a flame-retardant solution (28) to the coarse chips (20); subsequently removing the flame-retardant solution (28) from the coarse chips (20), in particular by applying a pressure difference, so that flame-retardant-containing coarse chips (32) are obtained; subsequently gluing the flame-retardant-containing coarse chips (32), so that glued coarse chips (20) are obtained; and compressing the coarse chips (20), so that the oriented strand board (44) is obtained.

Description

[0001] Method for producing OSB boards and OSB board manufacturing device

[0002] The invention relates to a method for producing OSB (oriented strand board), which can also be referred to as particleboard. According to a second aspect, the invention relates to an OSB board production device comprising (a) a particleboard production device for producing coarse wood chips, (b) a dryer for drying the coarse chips, which is connected to the particleboard production device, (c) a distribution device for distributing the coarse chips to form a layer of coarse chips, and (d) a belt conveyor, which is arranged downstream of the dryer in the direction of material flow, for conveying the layer of coarse chips. The OSB board production device can also be referred to as a particleboard production device.

[0003] It is advantageous to use as little flame retardant as possible in the production of flame-resistant OSB boards, as this is a considerable expense. One reason for this is that flame retardants themselves are expensive. Furthermore, flame retardants require more glue to achieve the same mechanical strength as a non-flame-resistant OSB board, which is also undesirable. Furthermore, most flame retardants are poorly soluble in water, so incorporating the flame retardant into the chips also introduces large amounts of water, which must be removed during subsequent processing.

[0004] US 2003 / 0059638 A1 discloses a process for producing OSB boards. Flame retardants are first applied to the chips by spraying or dipping. A vacuum or overpressure is then applied in a vacuum or pressure chamber to infuse the flame retardant into the coarse chips. In a further step, the cellulose material is treated with gaseous carbon dioxide. The moist cellulose material treated in this way is coated with a ground protein, e.g., soy flour, and pressed into a cellulose product such as plywood and particleboard.

[0005] WO 03 / 099533 A1 describes a process in which macrochips are first produced and impregnated with a flame retardant using alternating pressure impregnation or a vacuum pressure process. The resulting macrochips are then machined into coarse chips, which are then processed into OSB boards.

[0006] EP 2 241 426 A1 relates to a method for producing a wood-based panel, in which a fiber cake is first produced from wood fibers or wood chips and compressed using a pre-press. A vacuum is applied to this fiber cake on one side, and an impregnation medium is applied from the other side, which is distributed throughout the fiber cake as a result of the vacuum.

[0007] US Pat. No. 6,146,766 describes a pressure vessel vacuum process using a sodium silicate-borate mixture. This mixture is then polymerized by heat.

[0008] The invention is based on the object of improving the production of flame-retardant OSB boards.

[0009] The invention solves the problem by a method for producing OSB boards with the steps of (a) producing coarse chips, (b) applying a flame retardant solution to the coarse chips, (c) applying a pressure difference to the coarse chips to introduce flame retardant solution into the coarse chips, so that coarse chips containing flame retardant are produced, (d) gluing the coarse chips containing flame retardant, so that glued coarse chips are produced, and (e) pressing the glued coarse chips, so that the OSB board is produced.

[0010] The invention also solves the problem by a method for producing OSB boards with the steps of (a) producing coarse chips, (b) applying a flame retardant solution to the coarse chips, (c) then removing flame retardant solution from the coarse chips, in particular by applying a pressure difference to the coarse chips, so that coarse chips containing flame retardant are produced, (d) gluing the coarse chips containing flame retardant, so that glued coarse chips are produced, and (e) pressing the glued coarse chips, so that the OSB board is produced.

[0011] According to a second aspect, the invention solves the problem by a generic OSB board manufacturing device which has a flame retardant solution application device arranged to apply a flame retardant solution to the coarse chip layer, and a pressure difference generator for applying a pressure difference to the coarse chip layer.

[0012] An advantage of the invention is that the consumption of flame retardant can generally be reduced compared to conventionally manufactured OSB boards. By applying a pressure differential to the coarse chips, the flame retardant solution is at least partially absorbed into the coarse chips or excess flame retardant solution is removed. This reduces the formation of a crust of flame retardant on the coarse chips. Such a crust would be easily rubbed off during further processing, especially during mechanical transport and spreading, and would lead to a loss of flame retardant.

[0013] Another advantage is that by applying the pressure difference, flame retardant solution can be sucked and / or pressed into the coarse chips. According to a preferred embodiment, it is then possible to remove any flame retardant solution present on the coarse chips, for example, by suction or centrifugation. This results in less water being introduced into the coarse chips than with conventional processes. Therefore, less water needs to be removed during further processing of the coarse chips than with conventional OSB board manufacturing processes.

[0014] However, it is also possible for the flame retardant solution to penetrate the coarse chips without being promoted by positive or negative pressure. The flame retardant solution is then removed from the coarse chips, for example by applying a pressure difference. The feature that flame retardant solution present on the coarse chips is removed specifically means that flame retardant that has penetrated into the coarse chips is not removed. It has been found that the increase in fire resistance is primarily due to the flame retardant penetrating the coarse chips, whereas flame retardant that remains on the surface of the coarse chips predominantly leads to increased glue consumption. By applying the flame retardant solution to the dried coarse chips, the flame retardant penetrates into the interior of the coarse chips. A vacuum is not necessary for this.The subsequent removal of the flame retardant solution on the coarse chips prevents excessive glue consumption.

[0015] The pressure differential is preferably, but not necessarily, applied at a time and / or location separate from the application of the flame retardant solution. The time interval should be at least 1 second, especially at least 5 seconds. As a rule, the interval is no more than one week.

[0016] The feature of removing the flame retardant solution from the coarse chips is understood to mean that the flame retardant solution present on the surface of the coarse chips is at least partially removed. Preferably, the flame retardant solution that has already penetrated the coarse chips is not removed or is removed only to a small extent, for example, at most 10 percent by weight.

[0017] It is often also advantageous that the optional suction and / or injection of the flame retardant solution into the coarse chips results in fewer chemical reactions with the glue. Therefore, the glue quantity usually needs to be increased significantly less to compensate for the loss of strength caused by the addition of the flame retardant.

[0018] If - as provided according to a preferred embodiment - flame retardant solution that is removed from the coarse chips when the pressure difference is applied, blown off and / or vacuumed and / or spun off, is reapplied to the coarse chips, the amount of flame retardant solution that is not introduced into an OSB board is also reduced. Preferably, the removal takes place after the application of the flame retardant solution and not simultaneously therewith. This is understood in particular that the pressure difference is only applied to at least a majority of the coarse chips, in particular at least 80 percent by weight, particularly preferably at least 90 percent by weight, of the coarse chips, once the flame retardant solution has been applied. Particularly preferably, the location at which the flame retardant solution is applied to the coarse chips is spaced apart from the location at which the pressure difference is applied.Preferably, the distance is at least 10 cm, in particular at least 1 m. Preferably, the distance is at most 100 m.

[0019] It is advantageous if the flame retardant solution, which is removed from the coarse chips when the pressure difference is applied, particularly by blowing and / or vacuuming, is purified before reapplication, for example, by filtering and / or centrifuging. This separates any wood components from the flame retardant solution.

[0020] In the context of this description, coarse chips are understood to mean, in particular, wood chips that are in the size range 200±30 cm x 20±4 cm x 0.5±0.2 cm.

[0021] In particular, the method according to the invention is a method for producing flame-retardant OSB boards that meet DIN EN 13823 (single burner item) and / or are flame-retardant according to DIN EN 13501-1.

[0022] The flame retardant solution is preferably an aqueous solution. The flame retardant solution preferably contains at least one organic or inorganic phosphorus-containing and / or nitrogen-containing compound. According to one embodiment, the flame retardant is an inorganic salt.

[0023] The application of the flame retardant solution to the coarse chips is understood in particular to mean spraying or jetting.

[0024] According to a first embodiment, applying the pressure difference to the coarse chips means creating a pressure difference 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 0.5 ± 0.2 centimeters.

[0025] According to a second embodiment, applying the pressure difference to the coarse chips means applying a pressure to the coarse chips, in particular to the coarse chip layer, that differs from the ambient pressure, in particular by at least 200 hPa, preferably at least 400 hPa, particularly preferably at least 600 hPa. The pressure can be an overpressure or a negative pressure.

[0026] The feature that the coarse chips are compressed to form the OSB board is understood in particular to mean that at least the coarse chips are compressed. In particular, it is possible for additional chips that are not coarse chips to be compressed with the coarse chips. Furthermore, it is possible, and represents a preferred embodiment, for a first cover layer and a second cover layer to be scattered from the coarse chips and pressed together with a middle layer arranged between the two cover layers to form the OSB board.

[0027] The feature that the flame retardant solution is applied to the coarse chips means, in particular, that the coarse chips are not in a compressed form at the time the flame retardant solution is applied. In other words, the flame retardant solution is applied to uncompressed coarse chips.

[0028] Gluing is preferably carried out without any pressure difference applied to the coarse chips.

[0029] According to a preferred embodiment, the method comprises the steps of (a) arranging the coarse chips on a conveyor belt to form a coarse chip layer, and (b) applying the flame retardant solution to the coarse chip layer. In this way, the coarse chips can be wetted with flame retardant solution quickly, homogeneously, and reliably. Preferably, the pressure differential applied to the coarse chips coated with flame retardant solution is applied by applying a negative pressure to the underside of the conveyor belt. For this purpose, the conveyor belt is gas-permeable. 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.

[0030] Alternatively or additionally, the pressure difference is applied to the coarse chips wetted with the flame retardant solution by applying an overpressure to the upper side of the coarse chip layer. This occurs, for example, by the coarse chip layer first passing a roller that acts as a seal and then entering an overpressure zone where the overpressure is applied. The coarse chip layer lies on a gas-permeable conveyor belt, on the side of which, facing away from the overpressure zone, a lower pressure, such as ambient pressure or negative pressure, is applied. The coarse chip layer leaves the overpressure zone by passing a roller that acts as a seal.

[0031] Preferably, the process for producing the coarse chips includes drying the coarse chips. In other words, the coarse chips are dried before applying the flame retardant solution. Drying can take place on the same conveyor belt as the application of the flame retardant solution and, if appropriate, the application of the pressure difference, but this is not necessary. Preferably, the coarse chips are dried until they are kiln-dry. In this state, the flame retardant solution is absorbed particularly easily and quickly by the dried coarse chips.

[0032] According to a preferred embodiment, the coarse chips containing flame retardants are not dried significantly. This means, in particular, that the moisture content of the coarse chips containing flame retardants changes by a maximum of five percentage points, in particular by a maximum of two percentage points, before gluing and / or after gluing and before pressing.

[0033] Alternatively, the flame-retardant-containing coarse chips are dried. This is done, for example, using a belt dryer. The flame-retardant-containing coarse chips are preferably dried at a temperature of at least 50°C, in particular at least 55°C, and / or at most 100°C, in particular at most 90°C, and particularly preferably at most 85°C. The flame-retardant-containing coarse chips are preferably dried until a residual moisture content of at most 9% by weight, in particular at most 8% by weight, particularly preferably at most 10% by weight, particularly at most 9% by weight, particularly preferably at most 8% by weight.

[0034] Preferably, the coarse chip layer has a chip thickness that is at most four times, preferably at most three times, and preferably at most twice the thickness 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 , wherein for this arrangement, sections of two or more coarse chips lie on top of each other on a maximum of 75% of the test area and wherein at least 90%, preferably at least 95%, in particular 100%, of the test area is covered by coarse chips.

[0035] When applied to the coarse chip layer, the flame retardant solution preferably has a temperature of at least 50°C, preferably at least 60°C, in particular at least 70°C. A high temperature generally increases the solubility of the flame retardant in the solvent, so that less solvent, usually water, is needed to dissolve a given amount of flame retardant. Furthermore, the viscosity of water decreases with increasing temperature, so that the flame retardant solution can penetrate the coarse chips more easily.

[0036] It is advantageous if the flame retardant solution contains a concentration of flame retardant which 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.

[0037] It is advantageous if the flame retardant solution contains a concentration of flame retardant which is 30% by weight, in particular at least 40% by weight, preferably at least 45% by weight.

[0038] According to one embodiment, at least 18 weight percent, in particular at least 20 weight percent, preferably at least 22 weight percent, of flame retardant is applied to the coarse chips. In other words, at least 18 g of flame retardant is applied to 100 g of coarse chips. Preferably, at most 30 weight percent, in particular at most 28 weight percent, preferably at most 26 weight percent, of flame retardant is applied to the coarse chips. This information refers to the flame retardant in the flame retardant solution and is independent of the amount of solvent.

[0039] The flame retardant solution preferably contains a viscosity reducer. Alternatively or additionally, the flame retardant solution preferably contains a surfactant. This improves the wetting of the coarse chips.

[0040] It is advantageous if the process comprises the following steps: (a) producing coarse and middle-layer chips, (b) drying the coarse and middle-layer chips together, (c) separating the coarse and middle-layer chips, (d) applying the flame retardant solution, particularly to the coarse chips, preferably only to the coarse chips, (e) producing a first cover layer and a second cover layer from the coarse chips containing the flame retardant and a middle layer at least also from the middle-layer chips, and (f) pressing the first cover layer, second cover layer, and middle layer together to form the OSB board. This results in an OSB board that is, on the one hand, flame-retardant and, on the other hand, contains no more flame retardant than necessary.

[0041] The flame retardant solution 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 solution and / or the flame retardant can be recorded by irradiating it with UV light and / or taking an image of the particle board layer and / or the OSB board with a camera sensitive in the UV range. Based on the flame retardant distribution, 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 solution can then be controlled according to a preferred embodiment.In other words, a deviation between a target flame retardant distribution and the measured actual flame retardant distribution is determined and at least one of the parameters mentioned is controlled in such a way that the deviation is minimized.

[0042] An OSB board manufacturing device according to the invention preferably has an inspection system for detecting the flame retardant distribution in the coarse particle layer. This can be the distribution of the flame retardant over the surface of the coarse particle layer, i.e., the two-dimensional distribution in the longitudinal and width directions of the coarse particle layer, but not in the thickness direction.

[0043] Alternatively or additionally, the inspection system can be designed to detect the flame retardant distribution in the OSB board. This can then be the distribution of the flame retardant across the surface of the OSB board, i.e., the two-dimensional distribution in the longitudinal and width directions of the coarse particle layer and / or the distribution of the flame retardant in the thickness direction.

[0044] The inspection system preferably has a camera for capturing UV light and / or fluorescent light generated when the particle board layer or OSB is exposed to UV light. The inspection system preferably also has a UV light source for irradiating the particle board layer or OSB with UV light.

[0045] The coarse chip production device preferably has a chipper by means of which the coarse chips are produced from wood.

[0046] 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 lower the pressure in the respective suction chamber, the wider the valves open.

[0047] The suction chambers are preferably arranged in such a way that at least 90% of the area, preferably at least 95% of the area, particularly preferably 100% of the area 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 each.

[0048] 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 below 513 hPa under standard conditions).

[0049] Preferably, the segments are designed to apply different negative pressures. In particular, the pressures in at least two segments differ by at least 30 hPa. The greater the negative pressure, the more efficiently flame retardant that has not been absorbed by the coarse chips will be extracted. However, the greater the negative pressure, the more power is required. It may therefore be advantageous to first extract a large portion of the excess flame retardant at a lower negative pressure and then extract any remaining flame retardant at a higher negative pressure.

[0050] Preferably, an OSB board manufacturing device according to the invention has a distribution device, which could also be referred to as a homogenizer, by means of which a homogeneous distribution of the coarse chips is achieved across the transport width. For example, the distribution device has a combing device.

[0051] The OSB board production device preferably has an application booth within which the flame retardant is applied to the coarse chips. It is advantageous if a lock is arranged upstream of the application booth in the direction of material flow.

[0052] The OSB board manufacturing device preferably has a bucket for applying glue to the coarse chips. The bucket, which can also be called a gluing device, is preferably designed for applying PDMI (polymeric diphenylmethane diisocyanate) to the coarse chips. For this purpose, the bucket has, for example, a glue tank containing PDMI. For example, the coarse chips containing flame retardants are glued with 4 ± 0.5, in particular 4 ± 0.25, percent by weight of PDMI.

[0053] The manufactured OSB board preferably corresponds to building material class B according to SBI test DIN EN 13823.

[0054] The invention is explained in more detail below with reference to the accompanying drawings.

[0055] Figure 1 is a schematic view of an OSB board manufacturing device according to the invention for carrying out a method according to the invention and

[0056] Figure 2 is a schematic detailed view of the OSB board manufacturing device according to Figure 1.

[0057] Figure 1 schematically shows an OSB board manufacturing device 10 according to the invention, which has a coarse chip manufacturing device 12. The coarse chip manufacturing device 12 comprises a debarker 14 for debarking wood 16, a coarse chipper 16 arranged downstream of the debarker 14 in the material flow direction M, and a dryer 18 arranged downstream of the debarker 14 in the material flow direction M. The coarse chip manufacturing device 12 thus produces coarse chips 20. i (i = 1, 2, 3, ...).

[0058] The coarse chips 20.i thus produced are spread by a schematically shown distribution device 21 into a coarse chip layer 22 on a belt conveyor 24 and are wetted with a flame retardant solution 28 by means of a flame retardant solution dispensing device 26. Subsequently, a pressure difference is applied to the coarse chip layer 22 by means of a pressure difference generator 30, so that excess flame retardant solution 28 is removed from the coarse chips 20.i. This produces coarse chips 32.i containing flame retardant and having less flame retardant on their surface.

[0059] The flame-retardant-containing coarse chips 32.i. are coated with glue using a gluing device 33. The gluing device 33 can be, for example, a mixer or a coil, i.e., a rotating drum. The coated coarse chips 32.i. are spread by a first spreading head 34.1 to form a first cover layer 36.1. A middle layer spreader 38 spreads a middle layer 40 onto the first cover layer 20.1. A second cover layer 36.2 is spread onto the middle layer 40 using a second spreading head 34.2. The layers 36.1, 40, 36.2 are pressed into an OSB board 44 using a hot press 42.

[0060] The middle layer spreader 38 spreads middle layer chips 46.i, which are either produced by a middle layer production device or separated from the coarse chips 20.i by screening using a classifier 48, which is present in this case. Subsequently, the middle layer chips 46.i are glued in a second auxiliary bucket 50 and subsequently conveyed to the middle layer spreader 38.

[0061] By means of a return device, for example, a return line 88, flame retardant solution 28, which is removed from the coarse chips 20 when the pressure difference is applied to the coarse chips 20, is returned to the reservoir 50. The return line 88 can have a filter 90 by means of which wood particles are removed. Typically, the return line 88 also has a pump for pumping the flame retardant solution.

[0062] Figure 2 shows the distribution device 21, the flame retardant solution dispensing device 26, and the pressure difference generator 30. The flame retardant solution dispensing device 26 has a reservoir 50 containing the flame retardant solution 28. By means of a heater 52, the flame retardant solution 28 can be brought to a predetermined temperature T28, for which, for example, 50°C < T28 < 95°C applies. By means of a metering pump 54, the flame retardant solution 28 is directed to nozzles 56.k, which are arranged next to one another transversely to the material flow direction M, and from there sprayed onto the coarse chip layer 22.

[0063] The pressure difference generator 30 has a vacuum pump 58 connected to a plurality of suction chambers 6O.j (j = 1, 2, ...). When the vacuum pump 58 is operating, a pressure pj of, for example, 100 hPa < pj < 800 hPa is applied to the suction chambers 6O.j. It is possible that the pressures in the individual suction chambers 6O.j differ from one another. The suction chambers 6O.j are located on a conveyor belt 62 of the belt conveyor 24, which has openings, for example, holes. As a result, the pressure pj is applied to the coarse chip layer 22.

[0064] It is possible, but not necessary, for the differential pressure generator 30, as shown in Figure 2, to have a perforated metal belt 64 that presses onto the coarse chip layer 22 from above. Pressure rollers 66.1, 66.2, for example, are provided for this purpose. The suction chambers 60.j are located on the metal belt 64 on the side of the metal belt 64 facing away from the coarse chip layer 22. In the area of ​​the pressure chambers 60.j, an introduction pressure P22 of, for example, 100 hPa < P22 < 800 hPa prevails in the coarse chip layer 22.

[0065] It is also possible, but not necessary, for the differential pressure generator 30, as shown in Figure 2, to have two sets of suction chambers 6O.j and 6O'.j, between which the coarse chip layer 22 is arranged. It is possible, but not necessary, for the second set of suction chambers 6O'.j to be connected to a second pump 68. The second pump 68 can be a vacuum pump or a pressure pump.

[0066] It is possible that the pressure pj in the first set of suction chambers 6O.j is an overpressure and the pressure p'j in the second set of suction chambers 6O'.j is an overpressure.

[0067] Alternatively, it is possible that the pressure pj is an overpressure and the pressure p'j is a negative pressure.

[0068] Alternatively, it is possible that the pressure pj is a negative pressure and the pressure p'j is a negative pressure.

[0069] Alternatively, it is possible that the pressure pj is a negative pressure and the pressure p'j is a positive pressure.

[0070] An inspection system 70 having a camera 72 can be arranged downstream of the pressure difference generator 30 in the material flow direction M. The camera 72 detects light that is emitted or not absorbed by a dye in the flame retardant solution 28. Alternatively or additionally, the camera 72 detects fluorescent light. In this way, an actual flame retardant distribution kist(x,y) is determined, which indicates a concentration k of flame retardant as a function of the surface coordinates x, y. A control system 74 compares the actual flame retardant distribution kist(x,y) with a target flame retardant distribution ksoii(x,y) and controls the nozzles 56 k individually such that a deviation between the actual flame retardant distribution kist(x,y) and the target flame retardant distribution ksoii(x,y) is minimized.

[0071] It is possible, but not necessary, for the inspection system to have a UV light source 76 that illuminates the coarse chip layer 22 within a field of view G of the camera 72. The field of view G is the area of ​​the coarse chip layer 22 that is recorded by the camera 72. The inspection system 70 is not shown in Figure 1 for the sake of clarity.

[0072] Figure 1 shows that a cutting device 78 can be arranged downstream of the hot press 42 in the direction of material flow, which divides the OSB board 44 into individual board segments 80.1. In this case, it is advantageous if a second inspection system 82 is arranged, the camera 84 of which records a cut surface 86 of the respective board segment 80.1. From this, a second actual flame retardant distribution kist,2(y,z) is determined, which also encodes the depth dependence of the flame retardant concentration k. In other words, the second actual flame retardant distribution kist,2(y,z) encodes a depth profile of the dye.

[0073] The control 74 is designed to change the pressures pj in the at least one suction chamber 6O.j and / or a conveyor belt speed V62 of the conveyor belt 62, so that the second actual flame retardant distribution kist,2(y,z) approaches a second desired flame retardant distribution ksoii,2(y,z).

[0074] List of reference symbols

[0075] 10 OSB board manufacturing device 62 conveyor belt

[0076] 12 coarse chip production device 64 metal strip

[0077] 14 debarkers 66 pressure rollers

[0078] 16 wood 68 second pump

[0079] 18 T dryer

[0080] 70 Inspection system

[0081] 20 coarse chips 72 camera

[0082] 21 Distribution device 74 Control

[0083] 22 Coarse chip layer 76 UV light source

[0084] 24 Belt conveyor 78 Cutting device

[0085] 26 Flame retardant solution application device 80 plate segment

[0086] 28 Flame retardant solution 82 second inspection system

[0087] 84 second camera

[0088] 30 pressure difference generators

[0089] 86 cutting area

[0090] 32 flame retardant-containing coarse

[0091] 88 Chip return line

[0092] 90 filters

[0093] 33 Gluing device

[0094] 34 Spreading head i Running index

[0095] 36 Top layer j Running index

[0096] 38 Middle layer spreader k Concentration kact (x,y) Actual flame retardant concentration

[0097] 40 Middle class division

[0098] 42 Hot press ksoii (x,y) Target flame retardant

[0099] 44 OSB board division

[0100] 46 middle layer chips kist,2(y,z) second actual flame retardant

[0101] 48 Classifier distribution ksoii,2(y,z) second target flame retardant

[0102] 50 Reservoir medium distribution

[0103] 52 Heating

[0104] M Material flow direction

[0105] 54 Dosing pump p pressure

[0106] 56 nozzle

[0107] 58 Vacuum pump

[0108] 60 suction chamber

Claims

Patent claims 1. Method for producing OSB boards (44) comprising the steps: (a) Production of coarse chips (20), (b) Applying a flame retardant solution (28) to the coarse chips (20), (c) then removing flame retardant solution (28) from the coarse chips (20), in particular by applying a pressure difference, so that flame retardant-containing coarse chips (32) are produced, (d) then coating the flame-retardant-containing coarse chips (32) to produce coated coarse chips (20), and (e) Pressing the coarse chips (20) to create the OSB board (44).

2. The method according to claim 1, characterized by the steps: (a) Arranging the coarse chips (20) on a conveyor belt (62) so that a layer of coarse chips (22) is formed, and (b) Applying the flame retardant solution (28) to the coarse chips (20) lying on the conveyor belt (62), (c) Applying a pressure differential to the coarse chips (20) wetted with flame retardant solution (28) by applying a negative pressure to an underside of the conveyor belt and / or a positive pressure to an upper side of the coarse chip layer (22).

3. Method according to one of the preceding claims, characterized in that the production of the coarse chips (20) comprises drying the coarse chips (20), wherein the drying takes place before the application of the flame retardant solution (28).

4. Method according to one of the preceding claims, characterized in that the chip layer thickness of the coarse chip layer (22) corresponds to at most four times the coarse chip layer thickness of a coarse chip plant. Method according to one of the preceding claims, characterized by the step Removal of flame retardant solution present on the coarse chips. Method according to claim 5, characterized in that the removal of flame retardant solution present on the coarse chips (a) blowing off and / or suction by applying the pressure differential and / or (b) comprises a spinning process. Method according to any one of the preceding claims, characterized by the step Drying the flame-retardant-containing coarse chips (32), in particular after removal of flame-retardant solution present on the coarse chips. Method according to one of the preceding claims, characterized in that the flame-retardant solution (28) (a) has a temperature of at least 50°C when applied to the oriented strand board layer (22) and / or (b) contains a viscosity reducer, in particular a surfactant. A method according to any one of the preceding claims comprising the steps: (a) Production of coarse and medium-grade chips, (b) drying the coarse and medium layer chips together, (c) Separation of coarse and medium-layer chips, (d) Introducing the flame retardant onto the coarse chips (20) so that flame retardant-containing coarse chips (32) are produced, (e) Producing a first top layer (36.1 ) and a second top layer (36.2) from the flame-retardant coarse chips (32) and a middle layer (40) at least also from the middle layer chips (46) and (f) Pressing together first top layer (36.1), second top layer (36.2) and middle layer (40) to form OSB board (44). Method according to any one of the preceding claims 2 to 9, characterized in that (a) the flame retardant solution (28) contains a dye, in particular a colourless dye which absorbs or fluoresces in the UV range and (b) the procedure comprises the following steps: (i) depth-dependent, in particular optical, detection of a dye concentration of the oriented strand board layer (22) and / or the OSB board (44) so ​​that a dye depth profile is obtained, and (ii) Control of a conveyor belt speed, pressure differential and / or an area-specific application rate of flame retardant solution (28) based on the dye depth profile. OSB board manufacturing device with (a) a coarse chip-making device (10) for producing coarse chips (20) from wood (16), (b) a dryer (18) for drying the coarse chips (20) which is connected to the coarse chip production device (10), (c) a distribution device (21 ) for distributing the coarse chips (20) so that a layer of coarse chips (22) is formed, and (d) a belt conveyor (24) arranged in the material flow direction behind the dryer (18) for conveying the cellulose layer (22), characterized by (e) a flame retardant solution application device (26) arranged to apply a flame retardant solution (28) to the cellulose layer (22), and (f) a pressure differential generator (30) for applying a pressure differential to the oriented strand board layer (22). OSB board manufacturing device according to claim 11, characterized by an inspection system (70) for detecting a flame retardant distribution in the oriented strand board layer (22) and / or in the OSB board (44), wherein the inspection system (70) (a) a UV light source (76) and (b) camera (72) for detecting reflected UV light and / or fluorescent light. OSB board manufacturing device according to claim 12, characterized by a control system (74) configured for automatically controlling a conveyor belt speed, the pressure differential, and / or an area-specific application rate of flame retardant solution (28) based on the flame retardant distribution. OSB board manufacturing device according to any of the preceding claims, characterized in that the pressure differential generator (a) a vacuum pump (58) and a plurality of suction chambers, each connected to the vacuum pump (58) via a valve, wherein the valves have a degree of opening which increases with decreasing pressure (p) in the suction chambers (60) and / or . (b) comprising a pressure pump and a plurality of pressure chambers, each connected to the pressure pump via a valve, the valves having a degree of opening that increases with decreasing pressure (p) in the suction chamber (60). OSB board manufacturing device according to one of claims 12 to 14, characterized by a return device (88) for returning flame retardant solution (28), which has been removed from the coarse chips (20) by the differential pressure generator (30), to the flame retardant solution application device (26).

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