ES2375953T3 - PLATE MANUFACTURED IN A RESPECTFUL MODE WITH THE ENVIRONMENT FROM A WOOD MATERIAL. - Google Patents

Abstract

The invention relates to a method for producing a construction element, especially a panel, consisting of wood fibres, wood chips and/or sawdust. According to the inventive method, glue is applied to wood fibres, wood chips and/or sawdust, and the wood fibres, wood chips and/or sawdust provided with glue are compressed to form a construction element, especially a panel. The wood fibres, wood chips and/or sawdust are cooked in such a way that they decompose into solid and liquid constituents. The liquid constituents are separated and cooled in the sealed gastight system, before leaving the same. Odour pollution during the production is thus strongly reduced. The invention also relates to a device for carrying out the method and components which are produced according to said method.

Description

Plate made in an environmentally friendly way from a wooden material

The invention relates to a manufacturing process together with a corresponding device for a building element produced from pieces of wood such as fibers or chips. The invention particularly relates to plates produced from wood fibers.

From HK 1/88, pages 74 to 75, "Herstellung von MDF-Platten" a known known production process is known for the manufacture of a plate that has been manufactured from wood fibers. The chopped cooked wood is fed to a so-called refiner. In the refiner, the wood clippings are processed to obtain fibers and in particular with the supply of temperature and pressure with the help of grinding discs. The fibers are discharged from the refiner using steam and transported using a conduit called "Blue-line". The vapor pressure is about 10 bar in this respect. The temperature is about 150 to 160 ° C. In the "Blue-line" queue is added. Phenolic resins, urea resins or mixed urea and melamine resins are used as glue. Immediately after the addition of the tail, the "Blue-line" widens. Swirling is caused by widening. The tail is mixed with the fibers. The proportion of glue in relation to the fibers is approximately 22% by weight.

The "Blue-line" flows into the middle of a drying tube. The drying tube has a diameter of, for example, 2.60 m. Air with a temperature of 160 ° C is blown through the drying tube, a maximum of 220 to 240 ° C. In the drying tube the humidity is reduced from 100% to 8 to 11%. The steam generated in this respect is separated from the fibers in cyclones that are subsequently arranged and are taken to the environment through chimneys.

Disadvantageously, the steam is loaded with substances other than water. Thus, odorous substances are discharged into the atmosphere in this way. The environment is charged accordingly.

The fibers provided with glue are fed to a forming machine in a stratified form. In said machine the fibers are pressed in two phases. First a previous pressing takes place. The previously pressed fibers are then pressed using high pressure and supplying heat to obtain plates. The technical world has established that the plates crack when the temperature during pressing to obtain plates is below 150 ° C and, for example, is 140 ° C. Temperatures during pressing are typically found in this regard at 180 ° C.

An adhesive device for the production of fiber plates is known from EP 0 744 259 A2. From the publication US 5,554,330 a process for the manufacture of plates from a wood material is derived. Publication GB 791,554 discloses a process for mixing solid and liquid components. From the publication DE 41 15 047 C1 a device for continuously gluing wood shavings appears. DE-OS 1956 898 shows the continuous mixing of shavings or fiber with binders. From PCT / IB98 / 00607 and WO 98/37147, it is possible to obtain the glue from wood components. Publications DE-OS 44 41 017, US 11 17 95 and of Danish patent application No. 0302/97 disclose prior vaporization procedures.

US 4,882,112 describes a process for the manufacture of flexible plates or other comparable objects from vegetable raw materials, such as from sawdust or also rice bran or soy bean flour. To do this, the glue should be applied to the plant fibers in a first stage and this mixture is pressed at a later stage to obtain a construction element. The final pressing must be carried out in this regard at pressures between 100 and 200 kg / cm2 and at temperatures between 70 and 200 ° C.

An object of the invention is to develop an environmentally friendly process for the development of a construction element of the type mentioned at the beginning and to provide a corresponding device.

The object of the invention is achieved by one of the claimed methods. The device for carrying out the procedure has the characteristics of an additional first independent claim. Advantageous embodiments are obtained from the dependent claims.

In a particular embodiment, pieces of wood are separated primarily from solid and liquid components. Solid components are dried and glued. The solid components provided with glue are pressed to obtain a plate or other shaped body.

The liquid components particularly comprise lignin and hemicellulose. These substances cause, in the case of the temperatures prevailing during the drying, emissions that cause odorous pollution and, with it, an environmental load. Separating these liquid components before drying reduces the corresponding emissions during drying and / or immediately after drying. Correspondingly, the environment is less charged during the manufacturing process.

Liquid components are removed and / or processed hereinafter preferably at temperatures at which only reduced emissions are generated. If the temperatures of the liquid components are high and in particular they are higher than 90 ° C, the liquid components, as regards the environment, are kept in a gas-tight system in the meantime until the temperatures have dropped sufficiently.

In another embodiment of the invention the liquid components and in particular particularly lignin and hemicellulose are used as glue, that is, according to the invention they are mixed with the dried solid components. Preferably, the solid components are further processed to obtain fibers or chips. The liquid components can be separated from the solid components, for example, in a so-called agitator. The mentioned components that are obtained typically consist of: from 20 to 35% by weight of hemicellulose, from 45 to 50% by weight of cellulose and from 20 to 35% by weight of lignin. Cellulose is a solid component of wood.

In one embodiment, chopped wood is first introduced into an endless screw for compaction. From the screw of compaction the wood chopped in compressed state is conducted to a cooking vessel and it is cooked under high pressure. The cooking vessel is correspondingly exposed to high pressures. The pressure in the cooking vessel is particularly at least 1.2 to 2.2 MPa (12 to 22 bar). According to the state of the art, the chopped wood is generally cooked at pressures of only 0.8 to 0.9 MPa. Through the treatment of pressure and temperature the solid components of the wood (cellulose) are separated from the lignin and the hemicellulose, which represent the liquid components. Cellulose is in solid form. The other two components, lignin and hemicellulose, are liquid and can be used basically as a glue. In this regard, the main cause of adhesion strength is hemicellulose.

It is known, specifically from WO 98/37147, that the lignin and hemicellulose contained in the wood are separated from the solid components and then used as a glue in the manufacture of MDF plates. Disadvantageously, in this process strong emissions are generated that load around the production site. The emission problem is reduced according to the invention because the liquid components are separated from the solid components of the wood in a gas-tight container. The liquid components are separated and remain primarily in a gas-tight system connected to the container and in particular at least as long as the temperatures of the liquid are so high that strong emissions are generated. After separation of the liquid components, these are clearly cooled and discharged from the gas-tight system only at relatively reduced temperatures and, for example, are further processed, that is, in particular, sprayed through nozzles to the fibers. The liquid components are therefore clearly cooled and in particular particularly at least 30 ° C, preferably at least 50 ° C, before leaving the gas-tight encapsulated system and, therefore, odors. In this relatively cold state the development of odors is clearly reduced. Next, it is not critical to extract the liquid components of the gas-tight system.

Liquid components can be used as glue. This is possible in an environmentally friendly way, because the liquid components of the wood only leave the gas-tight encapsulated system and, thus, the odors, at reduced temperatures, in particular at temperatures clearly below 100 ° C, in particular below 70 ° C, particularly preferably below 50 ° C, and in this cold state, for example, they are applied to the fibers. In this way, it is therefore possible to reduce environmental loads in a particularly economical way.

The gas-tight system consists, for example, of a container together with connected pipes. Another container, which serves, for example, for cooling, may be part of the gas-tight system.

Particularly in the drying tube, in an application according to the state of the art, the glue is undesirably exposed to a temperature treatment. From approximately 80 ° C the tail is loaded or activated disadvantageously. The activated glue can no longer be used in the post-processing stage, in which the glued solid wood components are pressed to obtain plates.

The active part of the tail is reduced by the prior art mentioned. Of the 22% by weight that is usually used initially, only 1 to 8% by weight can be used even when the fiber and glue mixture leaves the drying tube. In this regard, the glue can be applied in a relatively cold state to solid wood components. This avoids unnecessarily wide activation of the queue ahead of time.

For HDF, MDF plates, as well as for chip plates, a formaldehyde-urea-based glue is currently used. The plates for the floor sector are manufactured by introducing melamine to the tail. This should prevent swelling, which may arise due to moisture.

Therefore, the problem is that a part of the tail is lost by means of the temperature treatment for the actual processing stage. Disadvantageously, therefore, essentially more glue should be added to the fibers or chips than is necessary to press the fibers or chips into a press with temperature supply and, thus, obtain the desired result, ie the MDF plate. Currently an MDF plate has approximately 60 kg of glue per m3. This amount can be reduced considerably if the glue is applied in a relatively cold state.

The liquid portions obtained in the described manner of hemicellulose and lignin are mixed in an embodiment of the invention in a chilled or cold state with another glue. The other glue has not been obtained, therefore, from liquid wood components. The proportion of hemicellulose and lignin in the prepared tail mixture is preferably not more than 20% by weight. The mixture also contains particularly reactive resins such as glue preferably based on formaldehyde-urea. In addition, glues and resins that are used in the prior art can be used.

If a mixture of glues containing a proportion of hemicellulose and lignin greater than 20% by weight is used, the pressing time (for additional use of synthetic glues that are currently available conventionally), during which the glued fibers , etc. Pressed to get the plate, it becomes relatively long. Therefore, it is economical to mix hemicellulose and lignin with another glue or mixture of tails. In this way, on the one hand, conventional glue can be saved and, on the other hand, the process does not become, due to long, relatively long and, therefore, less economical pressing times. Which upper limit for the proportion of hemicellulose and lignin is economically useful depends naturally on the reactivity of the glue with which the hemicellulose and lignin components are mixed. The above-mentioned upper limit of 20% by weight represents in this respect only an indicative value or a current experimental value.

The tail also contributes to emissions in the state of the art. By not exposing it now to higher drying temperatures, but by applying it to relatively cold temperatures to the solid components, the resulting tail emissions are also avoided. Therefore, only water, but no chemical, dries in the dryer or drying tube. With this, the corresponding environmental advantages are obtained, because the drying air is not disadvantageously charged with steam which, according to the state of the art, proceeds from the glue. The construction element is manufactured correspondingly with the environment. In addition, this embodiment has the advantage that portions of the glue are no longer disadvantageously activated during the drying process, so that they are not available for gluing itself of the wooden components to obtain the plate.

The solid components, which are particularly present in the form of fibers or chips and which are dried, are not advantageously loaded with the liquid components of the wood material and in the aforementioned embodiment they are not loaded with glue either. The corresponding liquid phases are not dried, therefore, in the dryer. Compared to the state of the art, a considerable amount of energy is saved. Energy saving results in not only considerable cost advantages, but also protects natural resources and, thereby, the environment.

Applying the glue only after drying to the wood components, the amount of glue needed for the manufacture of plates is reduced. A reduction to 45 to 55 kg per m3 of plate is achieved. A typical value is 50 to 52 kg per m3 of plate.

An essential magnitude for the proper sizing of fibers or chips is the "correct" ratio of the solid components with respect to the glue. In a preferred embodiment of the process the solid components are fed to a conveyor belt balance before gluing. On the conveyor belt balance, the solid components on the one hand are transported by means of a rotating conveyor belt, on the other hand they are weighed. This gives information about how much glue can be added to solid wood components in the later stage.

The solid components are fed by means of the conveyor belt balance to the next device. Possible weight variations of the solid components conducted are determined during transport, recorded and stored in one embodiment. This data is edited and can serve as a magnitude of adjustment for the amount of glue that is subsequently applied to solid components.

In one embodiment of the invention, the transport speed in the conveyor belt balance is controlled so that a uniform amount of solid components is supplied to the subsequent gluing device (device in which the solid components are glued. From the wood). By means of a modification of the feeding speed, therefore, a constant quantity is supplied to the subsequent device. The determination of the weight of the solid components that may be present in the form of fibers or shavings can be carried out in small steps and enables a uniform supply of the solid components with an accuracy of, for example, ± 1%.

It is not easy to provide the solid glue components in a suitably uniform manner, and particularly particularly when the solid components are present in the form of fibers. In addition, the fibers tend to swell together similarly to the wadding. Then it is difficult to evenly distribute the tail to the fibers. In one embodiment of the invention, the gluing is carried out, in this respect, in a mixer, in which glue and solid components are mixed together.

The mixer has, in one embodiment of the invention, means for cooling its housing. For this purpose, a housing with at least partially double walls, such as a double-walled tube that is part of the mixer housing, is provided in a particularly simple embodiment. A cooled liquid, such as cooled water, is conducted through the double-walled housing to cool the mixer or its walls. A layer of condensation water must be generated inside the walls by means of cooling. The cooling must be designed accordingly. The condensation water layer causes the solid components provided with glue not to stick to the walls and the mixer clogged.

After drying of the solid components they are distributed flat in an embodiment of the invention and a kind of curtain or mat is formed. This is then the case, in particular, in which the solid components are present in the form of fibers, because from them a mat or a curtain can be formed without more. Then glue is added and in particular it is sprayed in the shade. Preferably, a mixture of air and glue is sprayed on the curtain, in order to guarantee as uniform a distribution as possible of the glue. Through the formation of a curtain, the glue is distributed evenly in the solid components. This is particularly the case where the solid components are present in the form of fibers.

In one embodiment, a curtain formed, or a mat formed, of solid components is introduced into the mixer. Next, the curtain or mat is blown through nozzles with a mixture of air and glue. The glue is supplied through the nozzles, therefore, to the curtain or mat. Then the curtain or mat is preferably passed without contact through the mixer. By means of the contactless passage, adhesion of the solid components in the walls is advantageously avoided. This reduces fouling problems and the costs associated with them.

The glue is blown together with air particularly at a temperature of 40 to 70 ° C, preferably at a temperature of 55 to 60 ° C to the dried solid wood components. This allows the tail to reach a dry outer layer. Therefore, it is minimally activated. This is achieved in an improved way so that the subsequent mixture of solid wood and glue components does not stick to the transport device and the devices, such as inside the mixer.

The glue is prepared in an embodiment of the invention so that it hardens after a certain time. In this way the tail temperature treatment can be adjusted properly. In addition, a hardener that hardens after, for example, 60 seconds can be introduced or added. The preparation of the glue is carried out particularly in the mixer or a hardener is added together with the glue immediately before the mixer to the dry solid components.

The advantage is obtained that in a subsequent pressing of the solid components to produce a plate the glue solidifies rapidly. With this they can obtain shorter pressing times. In each individual case, the temporary hardening point is determined precisely by the expert to achieve particularly short press times. This represents another essentially economic advantage over the state of the art, in which they cannot obtain these short pressing times due to the necessary hardening times of the glue.

Because the glue is exposed to essentially lower temperatures than to date, it is possible to use more reactive glue compared to the prior art. It is also possible to reduce the components of chemical products such as, for example, formaldehyde. This achieves additional environmental advantages.

In one embodiment of the invention the glue is swirled with heated air and this mixture of air and glue is added to the dried solid components, that is, for example, to fibers or chips. The hot air that is introduced, for example, through a cabin together with the glue and the solid components dried in the mixer somewhat activates the surfaces of the glue droplets generated in this respect. This acts properly against an adhesion of solid components in the rear devices, that is, for example, in the walls of the mixer. Otherwise, for example, the mixer should be cleaned in a very short time. Then, therefore, production would stop disadvantageously. In addition, unwanted cleaning costs are correspondingly generated. These relevant economic disadvantages can be contrasted and compared with the disadvantage that the tail is activated a little. Through a few experiments, the expert can determine to what extent the tail is activated on its surface to achieve an optimal economic result. The proportion of activated tail is always reduced compared to the prior art.

After the addition of the glue to the dried solid components such as fibers or shavings, the free surface of the glue is further activated somewhat in an embodiment of the invention by means of a device suitable for this, to thereby facilitate the subsequent processing stages. After the addition of the glue to the dried solid components, that is, for example, to fibers or chips, particularly after leaving the mixer, the glued solid components, therefore, are preferably directed to an ascending tube which, in particular, it is 10 to 30 m, preferably about 20 m long. The diameter of the riser is particularly 1 to 4 meters.

Preferably, the riser tube also cools and, then, is for example double wall, to conduct a cooling liquid between both walls of the double wall. The objective is once again the formation of a layer of condensation water on the inner walls of the riser, so that the solid components glued on the walls do not stick.

By means of the riser, the glued solid components can be introduced particularly easily without contact by means of an air or gas stream.

It has been found that solid components, particularly when they are present in the form of fibers, must be conducted through the riser at a speed of at least 25 meters per second, preferably at least 35 meters per second. If the speed is lower, the fibers or chips remain strongly adhered to the riser in spite of the mentioned measures. This would make the ascending tube dirty unnecessarily fast. When lower speeds were planned, the riser had to be cleaned after only 8 hours. By adjusting an adequate speed the cycles could be extended to 7 to 8 days. Therefore, only the ascending tube had to be cleaned every week.

The maximum speed with which the solid components bonded with glue are blown through the riser depends on the effectiveness of the subsequent components or devices. Here the components should be considered

or subsequent devices must be able to process the supplied quantities of solid components. Currently, in practice, the operation could be executed without problems at an upper limit of 40 meters per second. From 50 meters per second the subsequent components used to date were overloaded. It is understood by itself that the upper speed limit can be controlled, as soon as effective subsequent components are available. Basically, it is valid that higher transport speeds in the riser are advantageous, because then the contamination problems and the associated production failures are correspondingly reduced.

By providing an ascending tube, the tail is activated somewhat later on the surface so as to be able to properly carry out subsequent processing steps. The length of the ascending tube is, therefore, adapted by the expert to the desired degree of tail activation. The expert will take into account in the design the transport speed in the ascending tube.

Following the addition of glue to the dried solid components, particularly following the partial activation of the glue in the riser, the solid components that are bonded with glue are directed to a cyclone. Here the tail has now been sufficiently activated on the surface due to the mentioned measures, so that it no longer remains attached to the cyclone. In the cyclone the solid components are separated and supplied by means of transport such as a tape to the next processing stage. Solid components are separated from the air in the cyclone. The transport means conducts the solid components in one embodiment to a monitoring apparatus. The solid components are analyzed in the monitoring apparatus to determine the thick components. Thick components are removed automatically. Thick components are, for example, lumps of glue.

The solid components are subsequently transported from the monitoring apparatus by means of a tape to the press and pressed into it to obtain plates. The press preferably consists of rotating press tapes pressed against each other that are properly tempered. In this way continuous pressing can be carried out. The temperature is adapted by the expert to the tail used in each case. The amount of energy and the resulting temperatures thereof are chosen for both pressing tapes in an embodiment, therefore, differently, to avoid deformation in the fabricated plate.

The nozzles, through which the glue is added to the solid components in an embodiment of the invention, are preferably conical shaped. Then, through the tip of the cone, the tail emerges in the form of droplets such that by means of it, advantageously, that is, an even distribution of the tail is improved.

It is advantageous to avoid cleaning operations and a production stop caused by them if the glue that arises for example from the nozzles does not come into contact with the subsequent tools, such as the tools found in the mixer. The glue, therefore, is directed directly, preferably, in the direction of the solid components, and in particular, it is dripping to achieve a distribution as uniform as possible. Otherwise, a sufficient distance between nozzles and subsequent tools in a mixer must then be considered. In practice it has been shown that the distance between tools in the mixer and the nozzles should be at least 1 meter, preferably at least 2 meters, if the tail is injected horizontally. The solid components are then introduced vertically at the beginning of the mixer and subsequently transported therein horizontally. The specific values of distances mentioned naturally refer only to a specific individual case. They are not valid in general, because finally they also depend on the speed at which the tail of the nozzles comes out.

If a mixture of glue and air is dripped in the direction of the solid components, simultaneously an air stream is advantageously available with which the solid components as far as possible without contact are first blown through the following devices such as a mixer or a riser and are thus transported. Instead of air, basically another gas can also be used.

Stirring apparatus are particularly used as tools in a mixer with which mixing of the solid components with the glue is obtained.

To achieve good results, the solid components are directed in the form of a curtain in front of the nozzles. This avoids the advantages already mentioned that the glue is injected into the mixer and the tools get dirty. Otherwise, the solid components will adhere to the tools and the mixer will clog very shortly and should be cleaned at short intervals.

The mixer tools, in one embodiment, are fixed to a centrally incorporated shaft and are formed by separate star-shaped bars that similar to a rudder blade are transformed into a flat region. Together a star is formed, for example, with four tools. Each two tools therefore form an angle of 90 °. Compared to the current of air flowing through the mixer, the rudder blades are inclined. This results in an air swirl and, therefore, a good mixing of the solid components with the glue. Other "stars" formed by the tools are fixed to the axis at similar distances. The solid components are then transported parallel to the shaft through the mixer. In a very general way, the tools are therefore designed particularly so that air is swirled together with the solid components. Therefore, tools that act as a propeller or as a propeller can be preferred.

From the solid components a curtain is preferably generated as follows.

A transport means, such as a conveyor belt or a conveyor belt balance, is provided at the end of at least one roller, preferably several rollers. Solid components pass through the roller or rollers. The rollers are particularly pressed against each other. It is basically not harmful if a slit stays between two rollers or a roller and a limiting surface. With this it is achieved that through the rollers a kind of curtain or mat is formed from the solid components. Therefore, the curtain shape is generated by the rollers.

In this regard, it is preferred to use a conveyor belt, because it ensures a uniform supply of fibers to the rollers. If a conveyor belt scale is used, in one embodiment the feed speed to the rollers is controlled such that a constant amount of fibers is supplied to the rollers. According to the state of the art, endless screws are regularly used to transport solid components in the manufacture of plates. However, solid components leave the worm in a relatively uneven manner. The consequence would be a curtain formed by correspondingly non-uniform solid components. A curtain of uniform thickness and width is advantageous to achieve a uniform distribution of the tail. In addition, it is achieved in such a way that the curtain separates the injected tail from subsequent tools effectively.

In particular, by means of rollers that are tightened together or separated from each other by means of a slit to generate the curtain, it is avoided that the solid components, in particular when they are present in the form of fibers, are subsequently transported in the form of a wadding or lumps. This would prevent the desired uniform sizing.

In order to process a sufficiently large amount of solid components to obtain a curtain and to achieve a particularly uniform curtain, more than two rollers are used in an embodiment, through which the solid components are passed to obtain a curtain. The rollers are preferably arranged one above the other in a displaced manner, such that the rollers form an acute angle with a transport means such as a conveyor belt or the conveyor belt balance. In this way, sufficient material can be supplied to the transport means, that is, for example, provided to the conveyor belt balance, in order to process a sufficiently large amount of solid components uniformly.

In practice it has been proven to date that together four rollers are particularly advantageous for generating a curtain from the solid components that are mechanically glued below.

The opening through which the curtain composed of the solid components is introduced, in one embodiment, to the mixer or in front of it, preferably corresponds to the maximum width of the mixer housing, that is, for example, to the diameter of the mentioned tube that simultaneously forms the walls of the mixer. This ensures that the total width of the mixer is covered by the curtain. Otherwise you could splash glue through the remaining openings laterally to the curtain inside the mixer and the mentioned dirt problems would arise.

If the total width of the mixer is not covered, not only splashes tail into the mixer, but also solid components that are on the edge, which form lumps, would be dragged. This reduces the quality of the material. As a consequence there would be the corresponding production problems. The processing of the material should be carried out disadvantageously and inexpensively.

The side walls of the mixer are preferably cooled to 7 to 15 ° C, in particular to 10 to 12 ° C. In this way, a layer of condensation water is deposited on the walls. Adhesion is prevented with the condensation water layer.

The temperatures mentioned are also suitable for the formation of a layer of condensation water on the inner walls of the interior of the riser.

Due, among other things, to the fact that a gaseous medium such as air for transporting fibers with the glue through the mixer is provided, the nozzles have a separation space for glue delivery in an embodiment of the invention. with the mixer housing. The nozzles are then facing an opening of the mixer housing. There is therefore a gap or annular passage between the nozzles and the opening, through which air is carried and thus can be fed properly. Furthermore, in this embodiment the air that is introduced through the slit or the annular passage can be preheated to provide the mixer with the desired temperature, in particular to thereby promote a desired activation of the tail on the surface.

The tools inside the mixer are fixed to a shaft in one embodiment. Around the axis, forming a ring, the nozzles are arranged to supply glue to thereby provide the fibers with glue evenly. The fibers or the fiber composite curtain are then preferably supplied perpendicular to the axis between the nozzles and the tools. Depending on the diameter of the mixer the nozzles are arranged in one or several rows in the form of a ring. For a correspondingly large diameter the total opening of the mixer is sprayed with glue, a second row of ring-shaped nozzles being arranged around an axis.

To the fibers composed of solid wooden components, in an embodiment of the invention, additionally glass fibers or plastic fibers are added. The addition is carried out particularly in the mixer

or immediately before it. In this way, particularly shaped plate-shaped parts can be prepared, which, for example, are intended as an interior lining in a car. Such shaped plates can be used in the automotive industry, for example, as a rear tray. Then it is sufficient to press only the layer system beforehand. A final pressing stage must not be carried out.

In the automobile industry, too many shaped parts such as fibers usually manufactured economically on an industrial scale are not necessary. Therefore it is economical to manufacture shaped parts that are particularly used in the automobile industry together with MDF plates (intended for the manufacture of panels) so as to be able to take advantage of fiber quantities on an industrial scale. The MDF plates provided for the manufacture of panels have an upper side and a lower side that run parallel to each other and are flat. These plates are a few millimeters thick. They generally have neither plastic nor glass fibers, since no particular shape should be produced that differs from a flat surface.

Sharp edges are problematic for the manufacture of shaped parts. In these, grooves tend to form. With the reinforcement of glass fibers or plastic fibers these problems are avoided or clearly reduced.

Shaped parts of the type mentioned are also used in the furniture industry. Such shaped parts are necessary, for example, for doors that are shaped in particular for design reasons.

Unlike plates composed of fibers, that is, for example, MDF plates that are intended for the manufacture of panels, it is sufficient for shaped parts that are only pre-pressed. Prepressing takes place at pressures essentially smaller than the actual pressing stage. The prepress pressure can only be 1/3 of the pressure used for the actual pressing stage. The pressing stage itself is carried out at pressures of 75 to 80 kg / cm2.

The proportion of glass fibers and / or plastic fibers in a shaped piece is 25% by weight, preferably 15% by weight, to achieve economic results. At least 1% by weight, particularly preferably at least 5% by weight, of glass fibers should be used.

Deflect fibers for the manufacture of shaped parts of the fibers that are used for the manufacture of MDF or HDF panels for panels, particularly for floor panels; It is in particular economically compared to the state of the art also independent of the other measures and features according to the invention mentioned herein.

In another embodiment of the invention, the solid wood components provided with glue are arranged, for example on a conveyor belt, in the form of a layer and hot water vapor is applied, for example by means of a steam blow. The layer is then pressed into a press, such as within two rotating, pressed tapes, to obtain the plate and, in particular, to obtain an MDF, HDF or chip plate. The invention is for the manufacture of particularly suitable fiber plates.

In one embodiment, steam is applied from the outside to both outer main surfaces of the layer. This can be done simultaneously to a previous pressing or compression of the layer. For example, by means of a vapor permeable conveyor belt, the solid wood components present in a stratified form are transported between two rigid plates. Then one plate is below the conveyor and the other above the conveyor. The distance between both plates may decrease in the direction of transport so that the layer is compressed by it. Through the nozzles located on the plates steam is applied to the layer. The humidity in the region of the surface of the layer is particularly increased by at least 2% by weight, for example up to 4% by weight and with it, for example, from 7% by weight to 9 to 11% by weight. The steam temperature is typically 100 to 130 ° C.

By applying steam, the temperature conductivity towards the middle of the layer is increased. Together, this results in a better pressing behavior and thus a reduction in the pressing time.

The already compressed layer or layer composed of solid wood components provided with glue can be divided into one embodiment such that, as it were, two layers are located one above the other. For example, the layer is transported for this on a conveyor belt. A belt or rail is arranged above and transversely to the conveyor so that it divides the layer that is on the conveyor. A steam application device is connected to the belt or rail, which is thus between the two layers. To the confining sides of both layers generated by the division or at least one of them, steam is applied as set forth above in order to enable faster pressing times. Following this application of steam the upper layer is on the lower one. The layers to which steam has been applied are transported to the press and pressed to obtain the plate.

The application of steam causes a sudden or direct heating of the fibers provided with glue immediately and / or in the pressing, and the pressing times can be shortened in this way. Productivity increases accordingly.

In the manufacture of floor panels it is of interest that the panels have hard outer layers and a soft inner layer. This can advantageously reduce, for example, step noise. If the application of steam to the surface is carried out and the interior region remains relatively dry, surface pressing will be carried out in a controlled manner. One cause of this is, among others, that the wet material is pressed better than the dry material. The surface region is therefore compressed precisely. Through a previous steam application it is also possible to control the evolution of the temperature. It is therefore possible to achieve harder outer layers in an improved way compared to intermediate layers.

If it is possible to reduce the pressing times, the length of the used double belt pressing equipment can be shortened. The costs for acquiring the pressing are clearly reduced. It can occur in a small space. The consequence is considerable economic advantages. Pressing the steam can reduce the pressing time.

In addition, additives that contribute to hardening can be added to the steam. In this way the desired hard surfaces are obtained in a further improved way when the surfaces are vaporized before pressing.

If you have hard outer layers, these can be relatively thin. In this way material can be saved together for the same plate thickness, because the soft intermediate layer is manufactured from comparatively little material.

The invention will be further explained by the following figures.

Figure 1 shows a section through a conveyor line balance 1 and a rear mixer 2. As indicated by arrow 3, dried fibers that have been manufactured from pieces of wood are fed through an opening of a casing 4 of the conveyor belt scale 1. A ramp 5 conducts the incoming fibers to the belt of the conveyor belt balance. The conveyor belt scale determines and controls the amount of material that is transported in the direction of the three rollers 6. The three rollers 6 are arranged one above the other and in a displaced manner, such that they form with the conveyor belt balance 1 an acute angle The fibers found on the conveyor belt balance are transported inside with this acute angle. They pass through the rotating rollers 6. In this respect a curtain is formed from the fibers that are subsequently transported perpendicular to the force of gravity in the direction of the arrow 7. In this way, the curtain penetrates the mixer 2 and specifically between a plurality of nozzles 8 and tools 9.

The mixer consists of a tube-shaped housing. The housing is formed by a double wall 10 and 11. In the center of the interior of the housing there is arranged an axis 12 to which the tools 9 are fixed. A tool 9 forms with the axis 12 a right angle. In each case four tools 9 in the form of rudder blades are grouped in the form of a star. Several of these grouped tools are fixed at constant distances to the axis

12. The anterior region, in which the curtain composed of fibers is introduced, lacks tools. This ensures that there is a sufficiently large space between the tools 9 and the nozzles 8. This space is provided so that the tail leaving the nozzles 8 does not impact the tools directly during the operation.

The diameter of the mixer housing corresponds to the width of the opening through which the curtain composed of fibers is introduced into the mixer. The width of the curtain is adapted to the width of the opening.

The nozzles 8 are arranged semicircularly around the axis 12 in an upper region. With this, it is caused that on one hand the curtain is provided with a glue evenly and on the other hand that the tail that comes out of the nozzles 8 does not directly impact parts of the mixer. Between the nozzles 8 and the housing 10, 11 a space is arranged such that a kind of annular passage is formed. Through this annular passage, air is aspirated. Means for calendaring the air that is aspirated are not represented. A mixture of tail and air is generated. The curtain provided with glue (in other words a mat formed by fibers) is transported by means of the air stream parallel to the axis 12 through the mixer 2. The axis rotates during transport and, with it, the tools 9. A In this respect, the glue is mixed with the fibers additionally. A cooled liquid is conducted between both walls 10 and 11 of the double wall so that a layer of condensation water can be generated inside the mixer on its interior walls.

In Figure 2 a top view of the mixer is shown parallel to the axis 12. For reasons of clarity only two tools are represented 9. By means of Figure 2, an arrangement of a semicircular row of the nozzles in the upper region is particularly explained.

An embodiment of the procedure in a complete context is explained in Figure 3.

As a starting material, wood from hardwood and coniferous trees in the form of logs, branches and / or wood from sawmill or industrial remains is used. The wood is first crushed into pieces with a size of approximately 20 x 5 mm in a crushing device 31. However, these pieces can also come directly from the forest or sawmills. They can be screened to separate pieces that are too small or too large. When the pieces of wood are the right size, they can be washed to remove adhering foreign bodies, particularly sand and earth. In this way, cutting tools and other tools are protected in the manufacturing process and subsequent processing and are not damaged.

Advantageously, sawdust is used which is supplied to a silo 32.

From the crushing device 31 and the silo 32, the wood components are supplied to a funnel-shaped pre-steam application vessel by means of conveyor belts.

The supply is typically carried out with a ratio of 6: 4 (60% by weight of chips, 40% by weight of sawdust). In this way sawdust is also used. This reduces costs more. Resources are saved in raw materials. The proportion of chips should predominate, because fibers are obtained and subsequently fiber mats with them that are mechanically stabilized. Therefore, a lower limit for the proportion of sawdust should not be maintained.

In the previous steam application vessel 33 the wood components are mixed, steam is applied previously and heated, in this respect, to 60 to 70 ° C. The wood components are then fed to a cooking boiler 34 by means of an endless screw for compaction. In the boiler 34 the wood components are cooked for approximately 2 to 3 minutes at a pressure of 11 bar at 16 bar and at a temperature of 140 to 180 ° C. Pressure and temperature are chosen so that a separation into liquid and solid wood components takes place.

The liquid components are separated from the solids and fed to a conduit 36 which is tightly gas-bonded to the cooking boiler 34.

Solid wood components are fed to a defibrillator machine 36 (refiner or defibrator). Defibrillator machine 36 typically comprises a stator and rotor that are driven by a motor. Solid components break down here into fibers.

The fibers, which in one embodiment are mixed with sawdust, are pneumatically fed to a drying tube 37. Next, fibers are referred to independently. In the dryer tube 37 the fibers are dried at 160 to 220 ° C. Drying develops quickly and economically, because the liquid components of the wood have already been removed.

From the dryer tube the fibers are driven to cyclones 38. Here the steam is separated. The fibers are expelled from below. The temperature of the fibers is then typically 50 ° C. The fibers are then glued mechanically in a sizing device 39 at comparatively cold temperatures. The glued fibers below have a temperature of typically 35 to 40 ° C. The glued fibers are conducted to one or more monitoring devices 40. In one embodiment the monitoring devices 40 comprise heating devices for heating the fibers at 55 to 60 ° C. The temperature increase is then advantageous when the plates must be pressed at temperatures above 150 ° C. The pressing stage can be accelerated in this way. Pressing times lead to larger production capacities.

The previously glued fibers are fed to one or more separation devices 41. Before the separation device 41 the fibers are conducted to a dispersion station 42. The dispersion station 42 provides the fibers previously glued to a conveyor belt. The conveyor belt drives the fibers to a previous press 44. Here the fibers are typically pressed to 2/3. The prepress comprises rotating belts between which the fibers are supplied and in this respect are pressed. The fibers then cross the forming street 45 which has various devices that ensure that the fibers are present in the desired shape. The forming lane leads in one embodiment to a steam application device 46. Here, steam is applied to the fibers above and / or below. The fibers can be divided parallel to the tape

5 conveyor and thus steam is applied to the “inside”.

The fibers are finally led to the main press 47 which consists of two curved sidewalks pressed together. Here, pressing above 150 ° C typically takes place. However, according to the invention, it is pressed at temperatures below 60 ° C.

The plates are then sawn in a saw device 48 and fed to a retention device 49. In

10 The retention device retains the plates so that they do not come into contact. In this way the plates are cooled.

The separated liquid components that are fed to the conduit 35 are cooled inside the closed gas-tight system. If these liquid components have cooled sufficiently, they are removed or fed to the gluing device 39.

15 The plates are then further processed to obtain, for example, panels. The plates are coated for this, for example, with papers, additionally sawn and provided with coupling elements by milling. The panels can serve as a wall or floor covering.

It has been surprisingly determined that in the pressing of the fibers no cracks occur below 120 ° C, in particular below 90 ° C, which are particularly observed in a temperature range between

20 120 ° C and 150 ° C. Then the resins used do not harden.

Claims (43)

1. Procedure for the manufacture of a construction element produced from wood fibers, wood chips and / or sawdust, in particular of a plate, with the steps:

-

glue application to wood fibers, wood chips and / or sawdust,

-

pressing of wood fibers, wood chips and / or sawdust provided with glue to obtain the construction element,

 characterized by that Pressing is carried out at temperatures below 60 ° C and at pressures from 75 to 80 kg / cm2.

2.

Method according to claim 1, wherein the wood fibers, wood chips and / or sawdust are broken down into solid and liquid components within a gas-tight system, the liquid components are separated from the solid components and carried outside the gas-tight system at temperatures below 90 ° C, in particular below 70 ° C.

3.

Method according to one of the two preceding claims, wherein the glue is applied to the wood fibers, wood chips and / or the sawdust at a temperature below 100 ° C.

Four.

Process according to one of the preceding claims, characterized in that layers are provided, in particular in the form of paper and / or decorative paper, which are preferably provided with resins, below and / or above the plate, in particular for manufacturing of laminated panels, and they are pressed in a press at temperatures preferably greater than 150 ° C, particularly preferably greater than 180 ° C.

5.

Method according to one of the preceding claims with the steps:

-

drying of wood fibers, wood chips and / or sawdust in a drying device,

-

glue application to wood fibers, wood chips and / or dried sawdust outside the drying device at a cooled temperature,

-

Pressing of the wood fibers, wood chips and / or sawdust provided with glue to obtain a construction element.

6.

Method according to one of the preceding claims, characterized in that the glue is applied to the wood fibers, wood chips and / or the sawdust by spraying a mixture of glue and gas on the fibers.

7.

Method according to one of the preceding claims, characterized in that the glue is applied in an amount such that 45 to 55 kg of glue are used per m3 of construction element.

8.

Method according to one of the preceding claims, characterized in that the wood fibers, wood chips and / or sawdust before the application of the glue are arranged on a conveyor belt balance and the conveyor belt balance and the application of glue are controlled so that the ratio of quantities between the glue and the wood fibers, the wood chips and / or the sawdust during the application of the glue is essentially constant.

9.

Method according to one of the preceding claims, characterized in that the wood fibers, wood chips and / or sawdust provided with glue are mixed together and / or swirled and in particular in a mixer (39) with cooled walls. .

10.

Method according to one of the preceding claims, characterized in that the fibers are shaped to provide a curtain or a mat and the glue is applied to the curtain or the mat or inserted into the curtain or the mat.

eleven.

Method according to one of the preceding claims, characterized in that the glue is applied together with heated air to the wood fibers, wood chips and / or sawdust and in particular at an air temperature of 40 to 70 ° C.

12.

Method according to one of the preceding claims, characterized in that the glue is applied together with a hardener to the wood fibers, wood chips and / or sawdust.

13.

Method according to one of the preceding claims, characterized in that after application to the wood fibers, the wood chips and / or the sawdust the glue is first activated only on its surface in a limited way.

14.

Method according to one of the preceding claims, characterized in that the wood fibers, wood chips and / or sawdust provided with glue are blown through a lifting tube.

fifteen.

Method according to one of the preceding claims, characterized in that wood is broken down into solid components and liquid components, and the liquid components are applied as glue to the wood fibers, wood chips and / or sawdust.

16.

Method according to one of the preceding claims, characterized in that the liquid components are cooled before application and in particular at least 30 ° C, preferably at least 60 ° C.

17.

Method according to one of the preceding claims, characterized in that lignin and hemicellulose are contained in the glue and in particular in a proportion of up to 20% by weight.

18.

Method according to one of the preceding claims, characterized in that plastic fibers and / or glass fibers are added to the wood fibers, wood chips and / or sawdust.

19.

Method according to one of the preceding claims, characterized in that as a construction element a piece shaped as a plate is manufactured.

twenty.

Method according to one of the preceding claims, characterized in that steam is immediately applied to the wood fibers, wood chips and / or sawdust immediately before pressing.

twenty-one.

Method particularly according to one of the preceding claims, characterized in that MDF and / or HDF plates are manufactured for floor panels and simultaneously shaped parts and the fibers used for it come from the same device, in particular from the same grinding device.

22

Device for the manufacture of a construction piece produced from wood fibers, wood chips and / or sawdust, in particular from a plate with a drying device (37), in which the wood fibers are dried, the wood chips and / or sawdust, and with a gluing device (39), in which the wood fibers, wood chips and sawdust are glued, and with means (44, 47) for pressing the wood fibers, wood chips and / or sawdust provided with glue to obtain a construction element, in particular a plate, characterized by a pressure and temperature control device designed so that the wood fibers, the wood chips and / or sawdust provided with glue are pressed at temperatures below 60 ° C and pressures from 75 to 80 kg / cm2.

2. 3.

Device according to the previous device claim with means of transport (1,7), with which the wood fibers, wood chips and / or sawdust from the drying device are transported to the gluing device (2, 8) characterized by which a press (47) is provided which comprises rotating pressing belts pressed against each other.

24.

Device according to the previous device claim with a device (36) in which the wood cuttings are processed to give fibers and in particular with temperature and / or pressure supply and / or with the aid of grinding discs.

25.

Device according to one of the preceding device claims, wherein the drying device

(37) presents a tube together with means with which a gaseous medium is heated and blown through the tube.

26.

Device according to one of the preceding device claims, wherein the transport means comprises a conveyor belt balance (1).

27.

Device according to one of the preceding device claims, wherein a mixer (2) is provided in which glue and wood fibers, wood chips and / or sawdust and in particular, particularly mechanically, are mixed together by means of tools stirring (9), the stirring tools being preferably arranged in the form of rudder blades or in the form of a propeller, in order to thereby cause an eddy of air in the mixer.

28.

Device according to one of the preceding device claims, wherein a mixer (2, 39) is provided together with means for cooling its housing (10, 11).

29.

Device according to one of the preceding device claims, wherein a mixer (2, 39) is provided, which comprises at least partially a double wall housing (10, 11) and in particular a double wall tube.

30

Device according to one of the preceding device claims, wherein the cooling means are provided for cooling a liquid and means for cooling the housing of a mixer (2, 39) and / or of a lifting tube with the cooled liquid.

31.

Device according to one of the preceding device claims with means for generating a layer of condensation water on the inner walls of a mixer (2, 39) and / or a lifting tube.

32

Device according to one of the preceding device claims with means (6) for feeding the fibers in the form of a curtain or a mat to the gluing device (39).

33.

Device according to one of the preceding device claims with means (6) for feeding the fibers in the form of a curtain or a mat to the gluing device (39), said means comprising rollers

(6) and a conveyor belt or a conveyor belt balance (1) being provided to feed the fibers to the rollers.

3. 4.

Device according to one of the preceding device claims with means (6) for feeding the fibers in the form of a curtain or a mat to the gluing device, said means comprising rollers (6), which are arranged both on top of each other and in shape. offset, in which the rollers are particularly arranged so that they form an acute angle (m) with a conveyor belt or a fifth conveyor balance (1).

35

Device according to one of the preceding device claims with nozzles (8), whereby the glue is applied to the fibers or chips, which in particular have a conical shape.

36.

Device according to one of the preceding device claims with means with which the glue is applied together with heated air to the wood fibers, wood chips and / or sawdust.

37.

Device according to one of the preceding device claims with means with which the glue is applied together with a hardener to the wood fibers, wood chips and / or sawdust.

38.

Device according to one of the preceding device claims with an ascending tube that runs essentially perpendicularly, which connects with the gluing device (39) and through which the wood fibers, wood chips and / or sawdust are glued in direction opposite to the force of gravity, preferably means being provided for cooling the walls of the ascending tube.

39.

Device according to one of the preceding device claims, with a cyclone (41) in which the fibers or chips provided with glue are separated and / or a monitor (39) by which the fibers or chips provided with glue can be optically controlled .

40

Device according to one of the preceding device claims with means for providing fibers in the form of a curtain or a mat in front of the nozzles (8) from which the glue comes out.

41.

Device according to one of the preceding device claims with a mixer (2) and an opening through which a curtain composed of fibers is introduced to the mixer or in front of it, corresponding the

opening to the maximum width of the mixer housing and the means for generating the curtain are preferably sized so that the width of the curtain essentially corresponds to the width of the opening. 42. Device according to one of the preceding device claims, wherein an ascending tube made of metal and / or a mixer made of metal is provided. 5 43. Device according to one of the preceding device claims, wherein means are provided (34) to decompose wood fibers, wood chips and / or sawdust within a gas-tight system into solid and liquid components and means to separate the liquid components within the gas-tight system from the solids and cool them. 44. Device according to the preceding device claim with means for applying the liquid components 10 to the wood fibers, wood chips and / or the sawdust at least partially in particular in the cooled state.