EP2018254B1 - Process and device for applying glue to dried fibers used in the manufacture of fiber panels - Google Patents

Description

The invention relates to a method and a device for gluing provided for the production of fiberboard, dried fibers. The fibers are preferably of lignocellulosic and / or cellulosic materials. The fiberboards are lightweight, medium density or high density fiberboard.

It is customary to glue fibers, which are intended for the production of MDF or HDF boards, in the wet state. However, such a so-called blow-line gluing has disadvantages. These are for example in the WO 02/14038 A1 described. The disadvantages of blow-line gluing can be avoided by gluing the fibers in the dry state.

From the WO 02/14038 A1 There is known a method and a device for gluing, wherein fibers are fed from a metering device through a vacuum-charged feed chute to a fiber roll which is provided on its surface with a plurality of pins. By rotation of the fiber roll, the fibers are deflected into a chute section and accelerated by the pins and a stream of air generated by the pins to approximately the peripheral speed of the fiber roll. The manhole section is bounded by a section of the circumference of the fiber roll and an opposite wall. At an outlet opening of the shaft section, the fibers emerge essentially in the horizontal direction of movement and are then sucked downwards or upwards and thereby deflected. In the deflection region, the fibers are glued by means of at least one spray nozzle. In this case, two symmetrically arranged opposite fiber streams may be provided, wherein the fiber streams after exiting the shaft section collide. The spray nozzles can be aligned both laterally on the combined fiber flow as well as in a suction down from above on the two partial streams.

The fiber roll serves to transport the fibers, to remove nonuniformities such as fiber agglomerates, and at the same time to stretch the fiber stream due to acceleration of the fibers in the direction of flow. The fibers settle in the curved shaft section before they emerge from this.

Also from the WO 03/106127 A1 It is known to guide fibers through a pneumatic transport shaft with a curvature, wherein the fibers are pressed by centrifugal force against an outer wall of the curvature and then passed over a ramp-like inclined baffle before being glued by spray nozzles. The possibility is also provided of sifting the fibers between leaving a metering device and gluing.

Similar gluing devices are in the documents DE 102 47 412 A1 . DE 102 47 413 A1 such as DE 102 47 414 A1 described. In this case, a hollow fiber circular stream is generated in order to produce the largest possible surface available for gluing the fiber stream and to achieve the most uniform gluing of the fibers. The fibers are glued in a chute or Faserabsaugrohr with vertical orientation and placed on a wire belt. In the chute, a jacket air stream can be provided, which surrounds the freshly glued fibers. The jacket air serves to prevent caking on the walls of the chute.

The DE 102 47 413 A1 discloses in Figure 9, two in series Beleimungseinheiten with alternately exchangeable chute or suction tube. That is, while a gluing unit is in use, the disused gluing unit may be subjected to cleaning. Of the Fiber flow is switched by two changeover to one or the other gluing unit.

From the DE 102 24 090 A1 is known to merge streams of glued fibers. This causes a compression of the fibers, and there are relative movements of the fibers, which lead to a homogenization of the distribution of the binder.

The invention is therefore based on the object to provide an effective and not expensive process of the type mentioned. Furthermore, the invention has for its object to provide an associated device.

The object concerning the method is solved by the features of claim 1. The fibers are fed from a fiber metering device of a transport device. The transport device has at least two pressure lines. In these pressure lines is generated by at least one fan, which is arranged between a discharge of the metering device and a respective outlet opening of the pressure lines, pneumatic pressure. Preferably, a fan is provided for each pressure line. By means of the pressure lines, the fibers are transported to Beleimungssprühdüsen. The fibers are at least partially guided in two separate partial fiber streams and exit in the form of two partial streams from outlet openings of the pressure lines. It can be provided that a plurality of pressure lines have a common outlet opening. The exiting partial flows are shallow partial flows, ie they have a relatively large width in relation to the thickness. The partial streams emerging from the pressure lines are arranged so that they meet at an angle of less than 180 ° and combine to form a fiber stream. Hereinafter, for simplicity, this angular arrangement of the two juxtaposed partial flows referred to as V-shape, although the two partial flows after exiting the respective pressure line do not have to have a straight course, but may be slightly curved and although the angle may be significantly larger or smaller than the legs of a "V".

Preferably, the two partial streams after leaving the respective pressure line have a substantially straight course, and the angle between the colliding partial streams may in particular be 45 ° to 135 °. Preferably, the angle is 50 ° to 110 °.

The fibers are glued with at least one gluing spray nozzle directed at the partial flow inner surfaces, that is, the two opposite surfaces of the V-shape, between the exit from the pressure lines and the merging into a stream. After the two partial streams have been brought together into one stream, the fibers of each broad side of the fiber stream are glued with in each case at least one gluing spray nozzle. The fibers of the combined fiber stream are sucked off. This can be done in particular by means of a further fan. Corresponding to the width of the fiber stream, a row of gluing spray nozzles arranged across the width can be provided in each case. The pressure lines are at least substantially closed except for respective inlet openings and the outlet openings.

With this method, high speed nonwoven fabrics having a high surface area can be produced. Due to the fact that two non-woven fabrics meet in a V-shape, spray nozzles which are arranged therebetween have a surface twice as large as when only one nonwoven fabric is produced. By comparison, at a desired fiber throughput, the width of the fiber web and thus the width of a corresponding device can be reduced accordingly. Overall, four fiber flow surfaces are available for gluing. The process is inexpensive, since in particular no fiber roll according to the WO 02/14038 A1 is required. This also contributes to a favorable energy consumption.

The direction of the extracted combined fiber stream need not be vertical, but is arbitrary. The direction of the combined fiber flow thus does not depend in particular on the gravitational force. The fiber stream, being based on air flow, may e.g. be sucked up too. As a result, a corresponding gluing unit can be installed in such an angular position that the freshly glued fibers of the combined fiber stream do not have to be deflected on the first path immediately after gluing, where the fibers still have the highest degree of cold tack, as a result of which gluing of the freshly glued leaves Fibers can be prevented on the walls of a transport device.

It is preferably provided that the fibers are subjected to an air-fiber direction on the way from the metering device to the glueing by means of the glue spray nozzles. By means of such pre-gluing, coarse wood particles (so-called "shives") or similar unevenness of the fiber flow, which arise in fiber production, can be relatively reliably detected from the fiber stream. Such irregularities lead to defects in the fiber board to be produced and can thus lead to plate rejection. However, due to the increased adhesion of dry glued fibers, the gluing of which takes place in contrast to the blow-line gluing after drying, it is at least very difficult, if not impossible, to spot such coarse irregularities from the dry glued fiber.

With the method according to the invention it is possible with relatively little effort to make a sighting of the fibers before gluing. The reason is that the air-fiber separator is integrated into the process so that no additional fiber metering device and no additional pneumatic transport device for the air-fiber direction are required. The fibers pass from a metering device first for sighting and then for gluing, and it can take place after the gluing an extraction in a uniform pneumatic transport device. Preferably, the Sighting of the fibers substantially immediately after leaving the at least one metering instead.
The sighting may in particular be a sighting, as in the WO 01/89783 A1 , is described. In this case, the fibers are fed through a shaft, which may in particular be a discharge shaft of the metering device, to an opening roller which is provided on its surface with a large number of pins and rotated in such a way that the fibers are deflected by the pins. As a result, the fibers are guided in a thin film substantially along a shaft section delimited by a partial section of the circumference of the opening roller and an opposite wall, with the fiber flow diverging, before they emerge essentially horizontally at an outlet opening of the shaft section. Subsequently, the fibers pass into a downwardly directed airflow generated by negative pressure. The air stream ruptures fibers which are isolated as desired and thus have a relatively low weight as particles, while impurities in the form of coarse material are fed by the gravitational force to a coarse material discharge. It may also be provided instead of the downward air flow, an upward air flow.
Preferably, it is provided that the fibers undergo a curvature of the respective pressure line before they emerge from this. The curvature is arranged in the flow direction so that the fibers emerge compressed from the pressure line by applying by centrifugal force to a relation to the curvature outer wall of the pressure line. In this way, the fiber stream can be compressed to a very thin fiber stream, which is thin, for example, a few millimeters. The curvature may in particular have the shape of a partial circle. The centrifugal force acting in the curvature also causes a separation of transport air and fibers, so that essentially flows on the inner wall relative to the curvature of the transport air. This airflow can after the exit be used from the pressure lines to protect inner surfaces of a wall of a collecting shaft in which the combined fiber stream is guided, before contact with freshly glued fibers.

Preferably, a single fiber metering device is used and a fiber stream, which is discharged from the metering device, divided into the two partial streams. In this way, the effort is kept low, for example, compared to the known device according to WO 02/14038 A1 in which two metering devices are provided.

Preferably, the speed of the fibers emerging from the pressure lines can be adjusted by means of a variable speed of the at least one fan which generates the pressure in the pressure lines. The speed of the exiting fibers may be in particular 10-100 m / s and preferably 40 m / s.

It can also be provided that the fiber density of the partial streams is controlled by the fiber speed. In this case, the fiber velocity is set as a function of a defined amount of fiber discharged per unit of time from the at least one metering device in order to keep the fiber density constant at a desired value. If a bend in the pressure lines is provided, the control is related to the fiber density before the curve.

Preferably, the spray nozzles, which are directed onto a surface of the combined fiber flow, flows around in the spraying direction of air, which serves for the extraction of the combined fiber flow. The sucked air has substantially the same flow direction as the gluing spray. This effectively prevents backflow of the spray and associated contamination of the nozzles. It can be provided that the flow rate of the intake air can be adjusted by changing a free cross-section of a suction duct in which the gluing nozzles are arranged.

Also, the at least one spray nozzle, which is directed to the inner surfaces of the partial flows between the escape from the pressure lines and the merging into a fiber stream, is preferably flows in the direction of spray of air, which serves for the extraction of the combined fiber stream, wherein the sucked air to prevent a Backflow of the gluing spray has substantially the same flow direction as the spray.

In the sucked air may be hot or hot air, the air is preferably sucked through intake ducts. Also, the guided through the pressure lines air can be heated accordingly. The fact that the spray nozzles are flowed around by warm air, a spray drying of the glue mist is intended. The warm or hot air ensures rapid surface drying of the glue droplets of the glue mist in its expanded form, whereby a cold tack of the glue is reduced. In this way, caking freshly glued fibers on the inner walls of a corresponding gluing device can be prevented. In particular, in this way caking of glue in shafts in which the spray nozzles are arranged avoided.

The air drawn in, preferably through the intake ducts, should only have a certain maximum temperature in order to avoid glue hardening within the spray nozzles. Because the inner walls of the spray nozzles heat up to the operating temperature of the air. For example, the intake air can only have a temperature of approximately 50 ° C., since glue hardening within the spray nozzles can occur at higher temperatures.

However, the temperature of the air passing through the pressure lines may be higher than the above-mentioned maximum temperature, for example higher than 50 ° C, because the air leaving the pressure lines together with the still unwished fibers does not come into contact with the spray nozzles , Because the degree of drying of the glue mist is directly related to is the air temperature, it is desirable to work with the highest possible temperatures exiting the pressure lines air.

Thus, it is preferably provided that the - preferably through the intake duct or the intake ducts - sucked air has a lower temperature than the air emerging from the outlet openings of the pressure lines.

The spray nozzles may be liquid pressure nozzles. Such nozzles spray glue by pressurizing. Alternatively, however, liquid-air atomizing nozzles can also be used. In these nozzles, the glue is atomized by air.

The above object is achieved with respect to the device by the features of claim 8. The method can be carried out with the device. The device has at least one metering device for fibers. Furthermore, a transport device is provided, which serves to transport discharged from the metering device fibers to Beleimungsmitteln. The transport device has at least two pressure lines, in which pneumatic pressure is generated by means of a fan. The fan is arranged between a discharge of the metering device and a respective outlet opening of the pressure lines. At least two pressure lines are provided at least over a certain distance, in which separate partial fiber streams are guided. Two partial fiber streams emerge at outlet openings of the pressure lines as a flat partial flow in such a way that the two partial flows meet at an angle of less than 180 ° and combine to form a fiber stream. In particular, reference is made to the statements concerning the method. It can be provided in particular that a fan is provided for each pressure line. This fan may in particular be a medium to high pressure fan. The pressure lines are at least substantially to the respective inlet openings and the outlet openings closed. It can be provided that a plurality of pressure lines share a common outlet opening.

The sizing means comprise at least one spray nozzle directed towards the inner surfaces of the sub-streams between exit from the pressure lines and merging into a stream. With regard to the more detailed description of the inner surfaces of the partial flows, reference is made to the above statements regarding the method. Furthermore, the gluing means have on both sides of the combined fiber stream at least one gluing spray nozzle. These spray nozzles are directed to the broad sides of the combined fiber stream. In general, a plurality of juxtaposed spray nozzles are provided over the width of the fiber stream in each case. As spray nozzles, which are directed onto the inner surfaces of the partial flows, separate spray nozzles are preferably provided for each of the two opposite inner surfaces. Furthermore, the device comprises means for sucking off the fibers of the combined fiber stream. These means may in particular comprise a fan which generates a negative pressure in a suction duct through which the combined fiber stream is guided.

It is also conceivable that more than two partial streams, for example, four partial streams are provided, of which in each case two are combined and glued as described above V-shaped. These pairs of partial flows could be arranged side by side across the width of a total fiber fleece, with a corresponding number of pressure lines would be provided. Also, such a device or a corresponding method is detected according to claim 8 or 1.

The device has substantially the same advantages as previously described in connection with the method. This also applies to the preferred embodiments of the device described below.

Preferably, an air-fiber separator is arranged between the at least one fiber metering device and the gluing means. The air-fiber separator can, in particular, be connected substantially directly to the at least one metering device or arranged adjacent to it.

The air-fiber separator may in particular be a classifier, as in the WO 01/89783 A1 is described. A feed chute, which may in particular be a discharge chute of the metering device, extends from a discharge of the metering device to an opening roller. The opening roller has a plurality of pins on its surface and is rotatable so that incident fibers are deflected by the pins. A chute section delimited by a partial section of the roll periphery and an opposite wall extends from an outlet of the feed chute in the direction of rotation of the opening roller. An exit opening of the chute section is arranged such that the fibers emerge substantially horizontally in an expanded fiber stream into an air passageway which carries a downwardly or upwardly directed airflow created by vacuum. In this case, a coarse material discharge shaft, which has an inlet that is opposite the outlet opening of the shaft section and a coarse material outlet arranged below the inlet, is connected to the air channel. The fiber stream is pulled apart by the opening roller due to acceleration, which improves the visual effect. The opening roller is preferably adjustable in its speed. As a result, the speed with which fibers are ejected from the shaft section can be varied, which influences the parcel trajectory, in particular of the large parts, which should reach the coarse material shaft during the visual process.

In the device, it is preferably provided that the pressure lines each have a curvature which is arranged near the respective outlet opening of the pressure line. The curvature is designed in the direction of flow such that the fibers due to centrifugal force to create a relation to the curvature outer wall of the pressure line and thereby compressed out of the pressure lines exit. The curvature may in particular have the shape of a partial circle. It could also be provided that the fibers after passing through the curvature still a relatively short travel straight along the outer wall before exiting the exit opening.

A collecting shaft, in which the partial flows unite, and the outlet openings of the pressure lines can be arranged to each other that air, which moves along an inner wall by the curvature of the pressure lines, after emerging from the pressure lines between the combined fiber flow and Wandinneninnenflächen the Manhole moves. As a result, the inner surfaces of the collecting shaft can be protected from contamination by the freshly glued fibers.

Furthermore, it is preferably provided that the fibers are discharged from a single metering device and a material divider divides the exiting fiber stream into the partial streams. In particular, if no fiber separator is provided, the material divider may be located in a discharge chute of the metering device. If a single fiber separator is provided, the material divider is preferably located adjacent to the viewing process in the air channel of the fiber separator or downstream of the fiber separator.

The pressure lines may be formed in the region of their respective outlet opening as a flat jet nozzle. The curvature described above may be part of the flat jet nozzle, so that the respective pressure line tapers approximately in the transition region to the curvature in cross section. It can be provided that a plurality of pressure lines have a common flat jet nozzle. The outlet opening of the flat jet nozzle is then a common outlet opening of the associated pressure lines.

It is advantageous if the speed of the at least one fan for pressure generation in the pressure lines is variable, preferably continuously. In this way, the speed of emerging from the pressure lines fibers can be adjusted. As a result, at a time per unit of time discharged from the metering amount of fiber, the fiber density in the Beleimungszone be set. The amount of fiber discharged from the metering device per unit of time can be predetermined in particular by means of a gravimetric metering, in which a weighing device is used. In order to keep the fiber density constant in the gluing zone, in particular a regulation can take place in which the fiber speed is changed as a function of the known amount of fiber discharged from the metering device. In the case of an intended curvature of the pressure lines, the control can relate to the fiber density of the partial flows before the curvatures.

Preferably, the at least one spray nozzle, which faces a surface extending across the width of the combined fiber stream, is disposed within a respective intake duct. Air is drawn in through the intake shaft, which serves to extract the fibers of the combined fiber stream. The spray nozzles are aligned so that the spray direction substantially coincides with the direction of the air flow. Preferably, the flow velocity of the air flowing through the two laterally arranged intake ducts can be adjustable in that a free cross-section of the respective intake duct is changeable.

The at least one spray nozzle, which are directed onto the inner surfaces of the partial flows, is preferably also arranged in a further suction duct so that it is surrounded by air for suction of the combined fiber flow and is oriented substantially in the flow direction.

Means can be provided for heating the air flowing through the intake ducts. These means may in particular be a heat exchanger or an air heater. These heating means may also be provided to heat the air flowing into the metering device.

But it can also be provided means that are used specifically for heating the guided through the pressure lines air. The reasons for this are in the Related to the method described. Therefore, these means, which in turn may in particular be a heat exchanger or an air heater, preferably designed so that the emerging from the pressure lines air can be heated to a higher temperature than the temperature of the intake duct or the intake ducts flowing air.

The spray nozzles may be liquid pressure nozzles or liquid-air atomizing nozzles.

Preferably, the enclosure of the gluing device is dimensioned such that the fiber streams have a distance from the walls which prevents fiber contact from occurring with the walls.

• Fig. 1 schematisch eine erfindungsgemäße Vorrichtung,
• Fig. 2 in perspektivischer Darstellung einen Teilbereich der in Fig. 1 gezeigten Beleimungsvorrichtung, in dem die Beleimung stattfindet,
• Fig. 3 eine schematische Teildarstellung einer Beleimungsvorrichtung, bei der jeweils zwei Druckleitungen eine gemeinsame Austrittsöffnung besitzen,
• Fig. 4 schematisch eine weitere Beleimungsvorrichtung, bei der zwei Lufterhitzer zur Erwärmung von Luft vorgesehen sind.

In the following the invention will be explained in more detail with reference to several embodiments, reference being made to the figures. Show it:

• Fig. 1 schematically a device according to the invention,
• Fig. 2 in a perspective view a portion of the in Fig. 1 gluing device shown in which the gluing takes place,
• Fig. 3 a schematic partial view of a gluing device, in each case two pressure lines have a common outlet opening,
• Fig. 4 schematically another gluing device, in which two air heaters are provided for heating air.

The gluing device according to Fig. 1 has a dosing bunker 1. The dosing hopper 1 has an inlet 2 for filling with dried wood fibers 3 according to arrow 37. By means of a bottom belt 29, the fibers 3 are fed to a discharge 4 with discharge rollers 4a. By the discharge rollers 4a larger clumps of the fibers 3 are dissolved. The bottom band 29 passes over a weighing device 5, which continuously detects the current fiber throughput weight (weight per unit time). The metering device 1 has an air supply 7. In an air supply line 8, a fan 9 is arranged, which supplies heated air by means of an air heater 10.

The fibers 3 pass through a discharge chute 11 of the metering device 1 as a fiber stream 6 to the direction of an air-fiber separator 70. In the region of an outlet 71 of the discharge chute 11 of the fiber stream 6 strikes an opening roller 72, on the surface of a plurality of pins 73 is arranged , The pins 73 taper with increasing distance to the axis of rotation of the opening roller 72 conically to a point. The opening roller can rotate at about 1000 rpm. The speed of the opening roller 72 is adjustable so that it can adapt to different materials to be dissolved.

By the opening roller 73 in the direction of the Fig. 1 Rotates counterclockwise, the fiber stream 6 is deflected by the pins 73 in a shaft section 74. The shaft section 74 is delimited by a partial section of the opening roller circumference and a wall 75. The shaft section 74 extends approximately from the outlet 71 to the lowest point of the opening roller 72 and has an outlet opening 76 there.

The outlet opening 76 of the shaft section 74 opens into an air channel 77 of the fiber separator 70. In the air channel 77, air is supplied via an air supply 78, the amount of which can be regulated by means of an air supply slide, not shown.

Opposite the outlet opening 76 of the shaft section 74, an inlet 79 of a coarse material discharge shaft 80 is arranged. The size of the inlet 79 may be adjustable by an adjustable slider (not shown). The coarse material discharge shaft 80 extends substantially in the vertical direction and has a coarse material discharge 81 at its lower end.

Downstream of the fiber separator 70, a material divider 12 is arranged in the air channel 77. The material divider 12 opens into two suction lines 13 and 14. These go into pressure lines 15 and 16, with a respective fan 17 and 18 is arranged therebetween. The parallel-connected fans 17, 18 may in particular be medium to high-pressure fans. The pressure lines 15, 16, which serve to transport fibers in partial flows 19 and 20, have a completely closed wall and are formed at their outlet end as a flat jet nozzle 21 and 22 respectively. The flat jet nozzles 21, 22 have at a respective outlet a part-circular curvature 23 and 24. The curvature 23 and 24 causes the fibers create by centrifugal force to an outer curvature 25 and 26, ie on the wall, the flat fan nozzle 21, 22 limited over their width at the larger radius of curvature. As a result, the fibers each compact to a thin fiber partial flow 27 and 28. The outlet width of the flat jet nozzles 21, 22 is arbitrary. It depends on the desired fiber throughput.

The flat jet nozzles 21, 22 open with an outlet opening 31 or 32 in a collecting shaft 33. The collecting shaft 33 has walls 43 and 44, which adjoin the outlet openings 31, 32 directly in the flow direction. The collecting shaft 33 passes into a suction duct 34, which has a larger cross-section than the collecting shaft 33. In the transition region between the collecting shaft 33 and the suction duct 34 respectively opens a suction duct 35 and 36th Walls 38 and 39 of the intake duct 35 and walls 40th and 41 of the intake duct 36 are adjustable to change the free cross section of the respective intake duct 35, 36. A further intake shaft 42 adjoins the collecting shaft 33, adjacent to the flow direction, adjacent to the outlet openings 31, 32.

The thin fiber partial flows 27, 28 meet in the collecting shaft 33 in a V-shaped manner and combine to form a fiber stream 45.

Within the intake duct 42, a series of gluing spray nozzles 46 (only one shown) are aligned over the width of the partial flow 27, aligned with the partial flow 27. Accordingly, a series of spray nozzles 47 is arranged aligned with the partial flow 28 over its width. Further, over the width of the combined fiber stream 45, a series of spray nozzles 48 are arranged, which are directed onto a surface of the fiber stream 45. Opposite a number of other spray nozzles 49 is arranged, which are directed to the opposite surface of the fiber stream 45. The spray nozzles 48, 49 are located in the areas where the intake ducts 35, 36 open into the suction duct 34.

Air which has been sucked in by suction means 57 and heated by means of the air heater 10 is supplied via an air line 52, in which a further fan 53 is arranged, and via further air lines 54, 55 and 56 to the suction ducts 35, 42 and 36, respectively. Instead of the fans 9 and 53, a fan between the suction means 57 and the air heater 10 could be provided.

At the suction duct 34, a Faserabsaugrohr 88 connects, which leads to a cyclone 89 with a rotary valve 93. In a line 90 for exhaust air of the cyclone 89, a powerful fan 51 is arranged. Cyclone exhaust air is usually fed to an air filter (not shown). Part of the exhaust air of the cyclone 89 can be supplied via an air line 91 as intake air to the fiber separator 70, in addition to air as indicated by arrow 92. The exhaust air, not shown by the air filter, which still has a residual heat from the process, can at least partially as intake air the heat exchanger 10 are supplied (not shown).

In Fig. 2 is the in Fig. 1 designated by the reference numeral 58 coarse area in which the gluing takes place, shown in more detail. The fibers are not shown. An entire forward end wall region of the intake duct 42, the collection duct 33, the intake ducts 35, 36 and the exhaust duct 34 are designated by the reference numeral 60. Of the opposite end wall region is designated 61. Out Fig. 2 It can be seen that the width of the flat jet nozzles 21, 22 is smaller than the width of the suction ducts 42, 35, 36 and the collecting shaft 33 and the suction duct 34. In this way it can be achieved that freshly glued fibers or glue in contact with the Walls of the said shafts come.

The described gluing device is based on the following mode of operation: The fiber stream 6 metered in and guided by the opening roller 72 is accelerated by the opening roller 72 and thereby pulled apart. Impurities and irregularities, in particular coarse wood particles, are mainly dissolved or reduced. As an exploded fiber flow, the fibers enter the air channel 77. Lightweight normal material 83, ie average single fibers, describe a short parcel of parcels after exiting the shaft section 74 due to their relatively low kinetic energy, and then move downstream from the air flow in the air channel 77 to be taken downstairs.

Coarse material 84, which is heavier than the normal 83, describes by its higher kinetic energy a longer throw parabola and thus passes into the Grobgutaustragsschacht 80. Heavy parts of the coarse material 84 fall into the Grobgutaustrag 81st

The fibers discharged from the fiber separator 70 as normal material 83 are fed pneumatically through the pressure lines 15, 16 to the gluing area 58 under pressure by means of the fans 17, 18. The pressure lines 15, 16 are closed except for the outlet openings 31, 32 of the flat jet nozzles 21, 22. The speed with which the fibers emerge from the flat jet nozzles 21, 22 is adjustable by way of a variable speed of the fans 17, 18. The speed is preferably set in such a regulated manner that the density of the partial fiber streams 19, 20 before passing through the curves 23, 24 is constant. For this purpose, the weighing device 5 gravimetrically measured the amount of discharged from the metering device 1 fibers. By adjusting the speed of the fans 17, 18, the speed and thus the density of the partial streams 19, 20 and 27, 28 is influenced. An associated control unit is not shown. The partial flows 27, 28, which have a flat rectangular cross-section, emerge from the outlet openings 31, 32 in such a way that they meet in a V-shaped manner and unite to form the fiber flow 45. The opposite inner surfaces of the fiber sub-streams 27, 28 are wetted by the spray nozzles 46, 47 with glue. The combined fiber stream 45 is wetted at its broad sides by means of the spray nozzles 48, 49 with glue.

Both the spray nozzles 46, 47 and the spray nozzles 48, 49 are flowed around by warm intake air from the air lines 54, 55 and 56, respectively. The advantages of the flow-through or the spray-drying of the glue mist due to the warm air in the intake ducts 35, 42, 36 have been described above. The spray nozzles 46-49 are liquid pressure nozzles or liquid-air atomizer nozzles. The spray nozzles 46-49 are each aligned substantially in the flow direction of the sucked air. By adjusting the walls 38, 39 and 40, 41 of the intake ducts 35, 36, the speed of the air sucked through these ducts can be adjusted in order to optimize the effect of the intake air to prevent backflow of the spray.

Along inner walls 62 and 63 of the bends 23 and 24, substantially only air flows since the compressed fiber partial streams 27, 28 abut the respective outer bended walls 25, 26. As shown by arrows 64 and 65, the air flows between the fiber streams 27, 28, 45 and the walls 43, 44 of the collection well 33, so that they are protected from caking of freshly glued fibers.

The gluing device according to the Fig. 1 and 2 is intended for fiber capacities that can be handled by a single metering device and a single fiber separator upstream of dry glueing. For larger fiber capacities can also be used a gluing device with two metering devices and two air-fiber separators. In such a gluing device, the material divider 12 is eliminated.

At the in Fig. 3 partially shown another embodiment of a gluing device according to the invention are provided with the same reference numerals as compared with the gluing device described above. In an air channel 77 of an air-fiber separator, a material divider 12 'is arranged, which opens into four intake pipes 13, 14, 13' and 14 '. These pass into pressure lines 15, 16, 15 'and 16', with a respective fan 17, 18, 17 'and 18' arranged therebetween. The two pressure lines 15, 16 are formed at their common outlet end as a flat jet nozzle 21 and the pressure lines 15 'and 16' at its common outlet end as a flat jet nozzle 22.

Due to the fact that in the gluing device according to Fig. 3 each have the two pressure lines 15, 16 and 15 ', 16', each having a round cross-section, a common flat jet nozzle 21 and 22, it is achieved that the pulp over the width of the respective flat jet nozzle is distributed as evenly as possible. The greater the difference between the diameter of the pressure lines and the width of the respective flat jet nozzle, the more advantageous an arrangement of a series of pressure lines to achieve a uniform fiber distribution in the flat jet nozzles.

Also at the in Fig. 4 shown further embodiment of a gluing device according to the invention are compared with the gluing device according to the Fig. 1 and 2 same features provided with the same reference numerals. The gluing device according to Fig. 4 differs from the gluing device according to the Fig. 1 and 2 in that further suction means 57 'and a further air heater 10' are provided. The suction means 57 and the air heater 10 provide in this embodiment only for the warm intake air, which is guided through the air ducts 54, 55 and 56, respectively. The air passing through the fan 9 in the air supply 8 of the Metering device 1 and the air channel 77 is supplied, however, is sucked by the suction means 57 'and heated by means of the air heater 10'.

The air heater 10 is designed so that the air flowing around the spray nozzles 46-49 has a temperature of, for example, a maximum of 50 ° C. By contrast, the air heater 10 'is such that it more strongly heats the air supplied to the metering device 1 or the air duct 77, so that the air emerging from the flat jet nozzles 21, 22 has a higher temperature than, for example, 50.degree.

Due to the described different air temperatures can be achieved that on the one hand no Leimaushärtungen arise within the Leimsprühdüsen and on the other hand, the degree of drying of the Leimnebel is as high as possible.

In this embodiment, the exhaust air from the cyclone 89 conducted through the air filter, not shown, could be at least partially supplied as an intake air to the heat exchanger 10 as well as the heat exchanger 10 '(not shown).

Apart from the mentioned deviating features, the device differs according to Fig. 4 not from the device according to the Fig. 1 and 2 ,

In the Fig. 3 Of course, the device shown in part could of course both the features of the device according to the Fig. 1 and 2 as the device according to Fig. 4 exhibit.

Claims (15)

1. A method for applying glue to dried fibers intended for the production of fiber boards, wherein the fibers (3) are transported by at least one fiber dosing device (1) through a transport device having at least two pressure lines (15, 15', 16, 16'), in which a pneumatic pressure is generated by at least one fan (17, 17', 18, 18') in such a way that the fibers emerge from outlet openings (31, 32) of the pressure lines (15, 15', 16, 16') in two separate fiber partial streams (27, 28),
   wherein the at least one fan (17, 17', 18, 18') is arranged between an outlet (4) of the at least one dosing device (1) and one of the outlet openings (31, 32) of the pressure lines (15, 15', 16, 16'),
   wherein the fibers emerge from the pressure lines (15, 15', 16, 16') as a flat partial stream (27, 28) in such a way that the two partial streams (27, 28) meet with each other at an angle of less than 180° and are combined to form one fiber stream (45), wherein the fibers are subsequently applied with glue by at least one glue spray nozzle (46,47) which is directed towards the inner surfaces of the partial streams (27, 28) between the outlet from the pressure lines (15, 15', 16, 16') and the combining into a fiber stream (45), and by at least one glue spray nozzle (48, 49) directed towards each of two surfaces of the combined fiber stream (45) extending across the fiber stream width, and wherein the fibers of the combined fiber stream (45) are sucked off.
2. A method according to claim 1,
   wherein the fibers each pass through a curvature (23, 24) of the pressure lines (15, 15', 16, 16') so that the fibers (27, 28) rest against an outer wall (25, 26) of the pressure lines (15, 15', 16, 16') by centrifugal force and thereby emerge compressed from the pressure lines (15, 15', 16, 16').
3. A method according to claim 2,
   characterized in that air (64, 65), which moves along an inner wall (62, 63) through the curvature (23, 24) of the pressure lines (15, 15', 16, 16'), is used after emerging from the pressure lines (15, 15', 16, 16') to protect the inner surfaces of walls (43, 44) of a collecting duct (33), in which the combined fiber stream (45) is guided, from contact with glued fibers (27, 28, 45).
4. A method according to one of the preceding claims,
   characterized in that the speed of the fibers (27, 28) emerging from the pressure lines (15, 15', 16, 16') can be adjusted by means of a variable rotational speed of the at least one fan (17, 17', 18, 18').
5. A method according to one of the preceding claims,
   characterized in that the respective at least one spray nozzle (48,49), which is directed towards a surface of the combined fiber stream (45), is circulated around by air in the spraying direction, which is sucked in for the extraction by suction of the combined fiber stream (45).
6. A method according to claim 5,
   characterized in that the flow velocity of the aspirated air can be adjusted by changing a free cross-section of an intake duct (35, 36), through which the air is guided.
7. A method according to one of the preceding claims,
   characterized in that the at least one spray nozzle (46, 47), which is directed towards the inner surfaces of the partial streams (27, 28), is circulated around by air in the spraying direction, which is sucked in for the extraction by suction of the combined fiber stream (45).
8. A device for applying glue to dried fibers intended for the production of fiber boards, comprising

   - at least one fiber dosing device (1),

   - a transport device which serves for the pneumatic transport of the fibers (3) discharged from the at least one dosing device (1) to gluing means (46-49), and comprises at least two pressure lines (15, 15', 16, 16'), which are designed in such a way that the fibers emerge in two separate fiber partial streams (27, 28) from outlet openings (31, 32) of the pressure lines (15, 15', 16, 16'), wherein
   at least one fan (17, 17', 18, 18') is arranged for producing the pneumatic pressure between an outlet (4) of the at least one dosing device (1) and one of the outlet openings (31, 32) of the pressure lines (15, 15', 16, 16'),
   the fibers emerge from the respective outlet opening (31, 32) of the pressure lines (15, 15', 16, 16') as a flat partial stream (27, 28), such that the two partial streams (27, 28) meet with each other at an angle of less than 180° and combine to form a fiber stream (45),
   and the gluing means (46, 49) have at least one gluing spray nozzle (46,47), which is directed towards the inner surfaces of the partial streams (27, 28) between the outlet from the pressure lines (15, 15', 16, 16') and the combination into a stream (45), and respectively comprise at least one gluing spray nozzle (48, 49) which is directed towards each of two surfaces of the combined fiber stream (45) extending across the fiber flow width,

   - means (33-36,42,51) for extracting by suction the fibers of the combined fiber stream (45).
9. A device according to claim 8,
   characterized in that the pressure lines (15, 15', 16, 16') each have a curvature (23, 24) which is arranged adjacent to the respective outlet opening (31, 32) of the pressure line (15, 15', 16, 16'), such that the fibers (27, 28) rest against an outer wall (25, 26) of the pressure lines (15, 15', 16, 16') due to centrifugal force and thus emerge in a compacted manner from the pressure lines (15, 15', 16, 16').
10. A device according to claim 9,
    characterized in that a collecting duct (33) provided for guiding the combined fiber stream (45) and the outlet openings (31, 32) of the pressure lines (15, 15', 16, 16') are arranged with respect to one another in such a way that air (64, 65), which moves along an inner wall (62, 63) through the curvature (23, 24) of the pressure lines (15, 15', 16, 16'), moves after emerging from the pressure lines (15, 15', 16, 16') between the combined fiber stream (45) and the inner surfaces of the collecting duct walls (43, 44).
11. A device according to one of the claims 8 to 10,
    characterized in that the pressure lines (15, 15', 16, 16') are designed as a flat jet nozzle (21, 22) in the region of their respective outlet opening (31, 32).
12. A device according to one of the claims 8 to 11,
    characterized in that the speed of the at least one fan (17, 17', 18, 18') is variable in order to allow adjusting the speed of the fibers (27, 28) emerging from the pressure lines (15, 15', 16, 16').
13. A device according to one of the claims 8 to 11,
    characterized in that the respective at least one spray nozzle (48,49), which is directed towards a surface of the combined fiber stream (45), is arranged within a respective suction duct (35,36) through which air flows for the extraction by suction of the fibers of the combined fiber stream (45), wherein the spraying direction coincides substantially with the direction of the airflow.
14. A device according to claim 13,
    characterized in that a free cross-section of the suction duct (35, 36) can be varied for adjusting the flow velocity of the aspirated air.
15. A device according to one of the claims 8 to 14,
    characterized in that the at least one spray nozzle (46, 47), which is directed towards the inner surfaces of the partial streams (27, 28), is arranged within a suction duct (42), through which air flows for the extraction by suction of the fibers of the combined fiber stream (45), wherein the spraying direction coincides substantially with the direction of the airflow.

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