EP1615757B1 - Press and method for producing panel board - Google Patents

Description

The invention relates to a pressing device according to claim 1 for the pressing of glued chips and fibers in particular for the production of substantially wood components consisting of plates, and a method according to claim 25 for the production of such plates.

In particular, the invention relates to a device for the continuous production of particleboard or fiberboard with a press drum and a pressure roller to produce a desired density of the chipboard or fiberboard and with a rotating press belt, especially steel strip, through which the chipboard or fiberboard against the surface of the press drum can be pressed, wherein a cleaning device of the device is applied substantially over the entire width of the press belt against this.

The invention further relates to a device or working method for the continuous production of particleboard or fiberboard, in which provided with a binder chip or fiber web to produce a desired density between a press drum and a pressure roller line pressure and in addition between a rotating belt and the press drum is applied a surface pressure.

Such a pressing device is basically constructed as follows. To a mat layered chip and / or fiber material, which may be in particular precompressed, is brought between rollers. Such a mat is also referred to as fiber fleece or chip or fiber web. A circulating belt or press belt, in particular a steel belt, can be tensioned by rollers. In this case, the chip material is placed between a steel strip or two steel strips. Temperature is supplied during the pressing. The resin hardens while doing so. When the compacted mat leaves the press, the final product is in the form of a chipboard, fiber HDF or MDF board.

In the simplest case, the pressing device comprises a total of four rollers and around a pair of rollers, a steel band is guided around. Initially, two rollers have a certain distance from each other. The bands are funnel-shaped in the direction of heating plates together. The actual compression takes place at the heating plates. Through the funnel shape, the supplied material is continuously compressed, temperature is gradually supplied. The funnel shape causes the material to get into the press and not build up in front of the press.

A disadvantage of such a press is therefore relatively long. The funnel needs about 3 meters of space. The temperature is gradually supplied. This also has the consequence that the required parking space for such a pressing device is relatively large and that results in relatively long pressing times. Currently, press times are typically 6-8 seconds per millimeter plate thickness.

In order to achieve shorter pressing tents and smaller parking space, a press is provided in a further embodiment, to bring the material obliquely coming from above into the press. By this measure, it succeeds to immediately compress the material suddenly, without damaging the material in front of the press. Due to the sudden compression, the funnel-shaped feed can be omitted. This saves space and pressing time. It is possible to approximately halve the pressing time per millimeter plate thickness.

When pressing, the steel bands can get bumps. The bumps affect the quality of the later product. If two steel strips are used for pressing, the risk of dents and negative influences on the product is doubled accordingly.

In order to avoid the problem or to reduce the problem, it is provided in an improved embodiment to guide the pre-glued chip or fiber material around a heating drum, which is also called press drum or calender, during the pressing. Around this heating drum around three quarters is led a steel band. About a quarter of the heating drum remains free, from this side, the material is fed diagonally. The steel heating drum is insensitive to dents. In this way it is possible to halve damage to the product by buckling in the steel strip,

Since the fiber mat is guided in the aforementioned case around the drum, this initially has a curvature. By post-conditioning, the curvature compensates again. There is finally a flat plate. Prerequisite for this, however, is that the plate is sufficiently thin. In this device plates can be made up to 10 millimeters thick. These plates offset each other by post-conditioning so that finally a flat plate product is present.

In the aforementioned apparatus, a main roll serving as a press drum may be provided, which has a particularly large diameter. Around this main roll around the press belt is led to three quarters. Several smaller pressure rollers are grouped around the main roller. Between the pressure rollers and the main roller, the press belt is guided through. The pressure rollers press in the direction of the main roller,

To generate the desired heat, the main roll and the pressure rollers are heated. Temperatures of up to 250 ° C are typically generated. The higher the temperature is selected, the faster the glue binds.

To be able to produce quickly, a high rotational speed of the press belt or the associated small rollers and the main roller is provided. The faster the speed of the rotating roller, the higher the production speed. The higher the rotational speed, the faster the temperature of the main roll and the press belt must be fed.

Known measures for rapid temperature supply are to increase the heating power accordingly. This measure reaches its limit when the heat energy to be provided is so large that it burdens the material too much. As a result of excessively high temperatures, damage to the device occurs.

A device or a working method of the type mentioned is for example by the DE-OS 20 50 325 known. Therein a continuous press is disclosed, are pressed on the chipboard or fiberboard continuously and then cut to length. The webs have a thickness of 0.8 to 12 mm and a width of 2500 mm. The pressing of the chipboard or fiberboard takes place between the circumference of the rotating and heated press drum and the standing under a high tension circulating steel strip. In addition, by means of a pressure roller, which rests against one of the chipboard or fiber plate side of the steel strip against this, the required line pressure applied to produce the desired density - The introduced into the press chipboard or fiberboard are for this purpose by means of the circulating steel strip under Maintaining a required surface pressure passed through the press and pressed during the wrap around the circumference of the press drum under heat.

Furthermore, it is through the DE 39 03-022 C1 Also known to move the two bearing body of the pressure roller independently, so as to be able to reproduce a first set on a press belt side distance on the opposite press belt side. In practice, it is of crucial importance that a trouble-free circulation of the press belt is ensured, because otherwise the continuous operation must be interrupted. In particular, impurities are to be avoided that get between the press belt and the pressure roller and thereby could cause deformations of the press belt. Although it is already known in principle to attach a cleaning device in the form of a brush to the device in such a way that it rests flat against the surface of the press belt, however, in particular the different spacing between the press drum and the pressure roller and conditional fluctuations in the press belt tension prove to be an obstacle. because the required cleaning performance can not be ensured in every case. To solve this problem, attempts have already been made to arrange the cleaning device on one of the pressure roller associated, movable holding means so as to be able to compensate for the different positions of the press belt directly. These However, the measure has proven to be only partially promising.

By DE 39 03 022 C1 Furthermore, a device or working method is known in which, in the loaded state of the press, initially only one of the two bearing bodies accommodating the pressure roller on both sides travels in the direction of the axis of rotation of the press drum until a predetermined pressure is reached. The determined by the pressure force distance between the press drum and the pressure roller is then measured by means of a first displacement sensor. The opposite second bearing body is then moved such that the distance measured on this side of the pressure roller by means of a second displacement sensor substantially coincides with the distance measured by the first displacement sensor and thus sets a uniform gap over the entire width of the chip or fiber web. As a disadvantage in. In this case, a continuous detection and correction of the gap measured on one side by a displacement of the bearing body on the opposite side of the pressure roller is required so as to over the entire Width of the span or fiber web to ensure uniform material thickness. The loop thus created requires a very fast adjustment of the bearing body, which is associated in practice with high costs. In addition, a consistent material thickness of the chip or fiber webs can not be ensured over a great length principle due. Furthermore, this method with the usual in practice and known for decades presses, in which the pressure roller relative to the press drum for adjusting the gap dimension in a simple manner can be moved in parallel, not feasible and therefore requires cumbersome adjustment solutions.

The invention is therefore based on the object to provide a device or a method of the generic type, soft or which avoids the aforementioned disadvantages of the generic prior art:

The invention is also based on the object, an apparatus for the continuous production of particleboard or fiberboard of the type mentioned in such a way that their operation is improved by a significantly increased cleaning performance. In particular, should be reliably removed by the cleaning device impurities on the press belt under all operating conditions.

An object of the invention is the acceleration of the production process at a relatively small pitch, which is to be exempted for the press. Overall, therefore, production costs should be reduced.

The invention is also based on the object, a device or to provide a working method for the continuous production of chip or fiber webs in such a way with the one over long lengths Consistent material thickness can be realized at a desired density with little effort. In particular, the method should also be feasible with such per se known continuous presses, which have a uniform over the width of the chip or fiber web adjustment of the gap dimension,

The object of the invention is achieved by a device or a working method having the features of the independent claims. Advantageous embodiments emerge from the subclaims.

According to the invention, a device is provided in which the cleaning device is arranged on a carrier web which can be driven circumferentially by means of a drive essentially transversely to the direction of movement of the press belt. As a result, the cleaning performance of the cleaning device is substantially increased by this moves transversely to the direction of movement and therefore a significantly higher relative speed of movement is realized. For this purpose, the cleaning device is arranged on a revolving press belt and thus enables continuous cleaning, wherein the circulating speed can also be determined, for example, in accordance with the feed movement of the press belt to be cleaned. Compared to a likewise conceivable embodiment of the holding means, in which this is arranged, for example reversie-rend or on a rotating brush roller, uniform cleaning performance over the entire width of the press belt are realized in the circulating driven cleaning device. The cleaning device and the carrier web can for this purpose also be integrally connected to one another,

A particularly advantageous embodiment of the present invention is also realized in that the carrier web to a holding means of the device in different positions can be fixed, thereby, the cleaning device having. Carrier web can be adjusted according to the respective set position of the press belt and the respective operating conditions.

It is particularly useful if the carrier web is arranged to adapt to the relative position and / or orientation of the press belt with at least two degrees of freedom on a holding means adjustable, This makes it possible in a simple manner to ensure a flat support of the cleaning device on the press belt , For this purpose, the carrier web is moved, for example, in the direction of the press belt and additionally inclined about its longitudinal axis until the desired flat contact is ensured.

Another particularly practical embodiment of the method according to the invention is achieved when the carrier web is moved by means of a hydraulic or pneumatic cylinder, so as to allow a continuous adjustment of the carrier web including the drive.

The adaptation of the optimal relative position between the Cleaning device and the press belt could be realized by a mechanical connection between the adjustable pressure roller and a storage of the carrier web. In contrast, a modification in which the device has a sensor for detecting the relative position and / or orientation of the press belt is particularly promising. As a result, even very small deviations of the press belt can be detected by the respective position and inclination and a corresponding compensating movement can be initiated immediately. The cleaning device can be moved independently of the pressure roller.

In addition, it proves to be particularly useful if the device has a sensor for determining the pressing force of the cleaning device relative to the press belt, so as to be able to set a suitable for the maintenance of an optimal cleaning pressure of the cleaning device against the press belt.

Furthermore, it proves to be particularly helpful if the device is additionally equipped with a second sensor, wherein in each case one sensor is assigned to one of the two edge regions of the press belt. As a result, changes in the orientation can be detected reliably and thus deviating cleaning effects between the two edge regions of the press belt can be avoided.

The cleaning device could comprise a woven fabric, a knitted fabric, a foam or a textile or fibrous surface. As a particularly suitable for the cleaning of such bands, however, a variant has been found in which the cleaning device has a brush and also after a werteren advantageous modification a wear indicator so as to make timely before an impermissible restriction of cleaning performance replacement of wearing parts can.

According to the invention, an object of the invention is also initially achieved in that a pre-compressed mat is guided obliquely from above into the press.

In order to achieve high processing speeds, in an advantageous embodiment of the invention, the press belt is heated not only by the aforementioned smaller rollers. Additionally or alternatively, according to the invention, temperature is also supplied to the press belt outside the area directly involved in the pressing step. In this way, it is possible to supply a reheated belt to the area that serves the actual pressing. Since the press belt has already been heated, the press belt can be brought to the desired temperature more quickly in the press area. Therefore, it is possible to increase the circulation speed without having to provide such a heating capacity in the pressure rollers, which leads to the damage of the device.

Temperature can thus be supplied to the press belt by thermal radiation so by radiators, which are placed near the press belt outside the actual pressing area.

In the device according to the invention, in one embodiment, there are not only the abovementioned pressure rollers which bear against the main roller under pressure. There is another also smaller roller provided, which is called in the following Spanwalze. By corresponding displacement of the tensioning roller, it is possible to tension the press belt. In this way, the pressing pressure is adjusted, with which the pre-compressed mat is pressed within the press. In order to keep the number of components to be used in the pressing device low, the temperature is also supplied via the tension roller. In this way, it is possible to supply a reheated belt to the area that serves the actual pressing. Since the press belt has already been heated, the press belt can be brought to the desired temperature more quickly in the press area. Therefore, it is possible to increase the circulation speed without having to provide such a heating capacity in the pressure rollers, which leads to the damage of the device.

In order to further increase the pressing speed, the diameter of the pressure rollers are further increased compared to the prior art. This increases the contact area between the press belt and the respective pressure roller concerned. The larger contact surface allows improved and thus faster energy supply. In addition, the energy transmitted per unit area decreases, which can lead to local overheating despite insufficient energy transfer to harden. This further measure also ensures that the desired temperature in the pressing area is made available at further increased rotational speeds.

According to the prior art, the smaller pressure rollers have a diameter of up to 2 meters. According to the invention, one or more pressure rollers are now used which have a diameter above 2 meters, preferably above 2.5 meters.

According to the invention, in one embodiment, the steel strip is guided around smaller rolls or pressure rolls. The smaller a smaller roll in diameter, the stronger the steel strip is bent. The more it is bent, the more it is strained. As a result, the service life of the steel strip are reduced accordingly. By providing said larger diameter, it is also possible to increase the service life of the steel strip accordingly. It also saves costs in this way. This size also applies to the tension roller, if the tension band moves around a stress-inducing circular section around the tension roller, z. B. more than 45 °.

By heating the tension roller or other areas outside the actual pressing area, the steel strip as a whole is uniformly brought to a desired temperature. Temperature gradients within the steel strip are kept small compared to the prior art. The avoidance of large temperature gradients has the consequence that the service life of the Steel strip is increased accordingly. Compared to the prior art, therefore, care is taken in the invention to increase the service life of the steel strip by a more uniform heating. Production costs are also reduced as the steel strip is very expensive.

For very large presses, a steel strip can cost up to 1 million euros. In a preferred embodiment of the invention, a comparatively short steel strip can be used. Here, the deployment costs are significantly reduced accordingly. Thus further production costs are saved.

Preferably, the rolls are heated as follows. Holes are provided near the surface of the cylindrical roll. The holes point
at the ends of an inlet and a drain on. The feed takes place from one end face of the roll. The process takes place via the other end surface of the roller. Hot liquid, in particular a hot oil, is passed through the holes through the axes. As a result, the respectively affected lateral surface is heated accordingly. As a result of the process, the hot liquid, ie, in one embodiment, the hot oil leaves the roll and is recirculated. During the tour in the circuit, the oil is heated outside the roller. Preferably, the oil is heated by a combustion process. In this way, wood dusts can be used to heat the rolls, which fall off during the production of the fibers and / or shavings. Wood dust can therefore be used for heating. The waste product wood dust is used directly for the production process. Transport routes for fuel are reduced accordingly.

In an advantageous embodiment of the invention, the main roll can be heated in the aforementioned manner.

In order to further improve the production process, in one embodiment, a contact pressure of the pressure rollers to the main roll of more than 8000 N per centimeter in the axial direction of the main roll, preferably of more than 10,000 N per centimeter is provided.

If the fiber fleece is fed obliquely downwards between the main roll and the first pressure roll, an abrupt compression, which is also referred to as line pressure, first takes place. Thereafter, the mat will rebound, thereby creating an undesirable density distribution in the surface area of the plate, which adversely affects the surface hardness, which is an essential plate property. In order to avoid this unwanted and usually relatively uneven density distribution, the pressure roller further downstream very small rollers, which advantageously reduce the gap increasingly. Typical diameters of the very small rolls smaller than the first aforementioned nip rolls are 300-450 mm. In an advantageous embodiment of the invention it has been found that these press very small rolls with a contact pressure of at least 150 N per centimeter in the axial direction against the main roll. To this As a result, the density distribution in the surface area of the plates to be produced is substantially improved. A jagged or wave-like course in the density distribution in the surface area is thus avoided. The result is a plate which has a particularly high density in the surface area. The density decreases towards the center of the plate. In the surface area, in contrast to a press without the very small rollers, a jagged density curve is avoided.

The desired high surface density, which is provided in particular by the sudden compression, is desired. As a result, for example, the need for lacquer is reduced in a subsequent lacquering step of the surface. The paint can then not penetrate into the product, which would increase the consumption of paint accordingly. Compared to conventional pressing devices, about 20-30% of the paint is saved in a subsequent painting step. Also, the hard surface is critical to wear resistance and the prevention of dents in use. A soft core improves impact sound absorption.

The very small rollers are immediately adjacent to the first pressure roller over which the material is fed obliquely. Several smaller rolls are used. In one embodiment, at least two very small rollers are provided which avoid the spring mat being deflected within the pressing area.

In an advantageous embodiment, at least four very small rolls are used.

In order to obtain a product of high quality, the tension with which the tensioning roller tensions the press belt is at least 25 N per cm ² . Preferably, the clamping force is 30 N per cm ² and more.

The very small rolls are followed by very small rolls, so-called trimming rolls. These other very small rolls are preferably in the upper region near the point where the plate leaves the press. These other very small rolls have hydraulic cylinders inside. By the hydraulic cylinders inside the other very small rollers, which are arranged in the upper area, the surface of the very small rollers or, the lateral surface can be deformed. Individually, the surface areas or the lateral surface along the axis can be adjusted. By suitable control of the hydraulic cylinder, the pressure in the upper region can be adjusted so that the desired plate thickness in this region can be adjusted in a targeted manner. It is thus possible to further reduce deviations from the desired plate thickness. A subsequent grinding step can be correspondingly avoided or even completely saved in order to achieve the ideal desired plate thickness.

If the steel belt runs around the various rollers, the steel belt tends to leave the ideal line laterally to the direction of movement and run out of the roller. This problem is greater, the greater the orbital speed. To avoid this problem, the course of the steel strip is scanned continuously. For this will be used mechanical and / or optical sensors. If a press belt threatens to leave the ideal line, then a corresponding roller or the axle is suitably continuously positioned differently. So there are provided with each roller actuating means with which the axis or the course of the axis can be changed. Depending on leaving the ideal line, the axis is continuously adjusted so that the press belt is returned to the ideal line. Through the continuous scanning and the continuous adjustment of the gradients of the various axes a sudden adjustment is avoided. A correction of the band position by sudden adjustment would have the consequence that the forceful lateral displacement can affect the quality of the surface of the steel strip. As a result, the quality of the product is lowered accordingly.

In a further embodiment of the invention, there is an electronic control to push the smaller rolls parallel to the main roll. The axes of a smaller roll are moved hydraulically towards the main roll. Each hydraulic element to the right and left of the roller can be individually controlled and moved. By means of an electronic system, the at least two hydraulic elements are moved to the right and left of a smaller roller in such a way that a smaller roller is guided absolutely parallel to the main roller.

In a further embodiment of the invention, the in particular pre-compressed mat is guided by means of a belt to the area from which the pre-compressed mat is guided obliquely from above into the press.

In a further embodiment of the invention, at the beginning of a continuous compression of a particular pre-compressed mat, first a relatively large entrance slit, d. H. Gap, adjusted. At this time, one or more smaller rollers have not been adjusted with the actual contact pressure in the direction of the main roller. Only when a pre-compressed mat leaves the pressing device again, the desired final pressure is set with the press the smaller rollers in the direction of the main roller. In this way, it is possible to reduce the required starting power. The pressing device can therefore be designed with lower starting performance. This reduces the cost of the pressing device. Overall, the production costs will be further reduced.

In order to monitor the production, the device includes a sheath having various viewing windows. Through the viewing windows, the production inside the press can be manually monitored. Through the aforementioned holes in the sheath further internal cleaning can be made.

In a further embodiment of the invention, a so-called transfer table is located in front of the entry area into the press. The pre-compacted mat is brought to the transfer table by means of a conveyor belt. The transfer bridges the distance between the actual feed into the press and the assembly line. This way will. the proper supply of the pre-compressed mat further ensured.

In a further embodiment of the invention means for heating the transfer table are provided. As a result, the pre-compressed mat is already pre-heated in the pressing device immediately before entry. Due to the additional supply of temperature immediately before the entry of the pressing device, it is further possible to shorten the pressing time. Overall, this will further increase production output.

In a further embodiment of the invention, the transfer table is designed so that hot steam can be supplied to the pre-compressed mat. By supplying steam, the pre-compressed mat is further suitably heated. By supplying steam, the temperature is transported very quickly into the interior of the mat. As a result, the production is further improved suitable.

In a further embodiment of the invention, means are provided above the transfer table to heat the pre-compressed mat from above and / or supply steam from above. Thus, the mat is heated from both sides immediately before entry into the pressing device or heat into the interior of the mat through the steam pulse into it. The production output can be increased further.

To ensure the quality of production, there is a device with brushes, which brushes off the main roll continuously. Steel wire brushes are preferably used to brush off the main steel roller.

In order to further improve production, in a further embodiment of the invention, a polishing device is provided with which the main roll can be polled during production. Belde aforementioned preparation facilities, so the Bürsteinrichtung and the bollard can be moved in an oscillating parallel to the mantle surface. In this way, a uniform treatment result is ensured.

Further, means are provided to bring the treatment facilities, so the polishing device and the Bürsteinrichtung to the main roller or drive away again from the main roller.

According to the method is intended to brush continuously during production. The polishing device is approached only when needed.

The polisher grinds the main roll when needed. It is preferably a roller with a grinding belt. By means of the abrasive belt, the surface of the main roll is ground if necessary. The surface of the polishing device preferably has very fine-grained corundum material.

The polishing device is turned on when shading is registered on the surface of the main roller. This can be done by optical Sensors happen. In practice, however, it is also possible for one person to monitor the quality of the surface of the main roll. The person manually initiates the turning on of the polisher when shading is registered in the surface.

Since the shading on the surface of a main roll is noticeable by a shading of the product, it is sufficient to observe the quality of the plate. If a shading is detected here, then the bollard device is switched on according to the method.

In a further embodiment of the invention, one or more brushes are provided which brush off the press belt. This further ensures the production quality. Deposits on the press belt can not affect the product quality.

In an advantageous embodiment of the invention is brushed perpendicular to the transport direction of the press belt. This makes it possible to remove deposits on the press belt side. This avoids the build-up of deposits before the brushing direction and, finally, the brushing direction can no longer cope with the material.

Advantageously, a so-called band brush is used. This is a circulating belt, which is spanned by two rollers. The band is externally provided with steel bristles. These are guided perpendicular to the direction along which the press belt is guided. So deposits are swept sideways on the press belt. The product quality is ensured accordingly.

In a further embodiment of the invention, the Bürsteinrichtungen are arranged movable. By the method, it is possible to provide a desired distance between a Bürsteinrichtung and the press belt. This method is particularly necessary when new plate thicknesses to be produced are set. In this case, the distance between a smaller roller and the main roller is appropriately changed. As a result, the course of the press belt changes slightly. The possibility of tracking ensures an optimal brushing result.

In a further embodiment of the invention, a polishing device is provided with which the press belt can be polished.

This polishing device for the press belt can also be driven zoom only when needed to the press belt. It is then switched on when the product quality deteriorates and polishing the main roll does not lead to a sufficient product improvement.

In addition, a working method is disclosed which can be carried out particularly well on a device according to the invention:

According to the invention, a working method is provided in which initially set a desired gap between the press drum and the pressure roller and then the raw density determining line pressure is adjusted by changing the supply of material of the chip or fiber web. As a result, a uniform material thickness can be ensured over a large length of the chip or fiber webs. In order to keep constant the line pressure between the press drum and the pressure roller at the same gap, the material supply is varied in a simple manner. As a result, the method can also be carried out with conventional presses, which does not have an independent for each side of the chip or fiber web adjustment of the gap. In addition, the effort to carry out the method is substantially reduced, because thereby an independent of the current measurement value adjustment of the bearing body is unnecessary. The effort for the regulation of the material supply is comparatively low in contrast.

In this case, a modification of the method has proven in practice to be particularly promising when the line pressure is detected by means of a pressure sensor. As a result, the line pressure determining the required density can be detected by means of the pressure sensor and used directly as a controlled variable in the material supply. As a result, a largely constant density is ensured, whereby at the same time a substantial increase in quality can be achieved,

Another particularly advantageous modification of the invention is also achieved in that in each case a pressure sensor is assigned to the lateral edge sections of the chip or fiber web. As a result, varying pressure conditions can be detected across the width of the chip or fiber web and the material supply can be dimensioned differently over the width of the chip or fiber web. The method can therefore be further optimized with little effort.

The material supply is basically determined by the volume flow of the chip or fiber web forming chip or fiber substance. For example, this can be limited by means of a scalper roller, the amount supplied.

Further advantages will become apparent from the following description and the accompanying drawings. Likewise, according to the invention, the features mentioned above and even further can be used individually or in any desired combinations with one another. The mentioned embodiments are not exhaustive and have exemplary character. In particular, the invention is not limited to calendering presses and can also be transferred to double belt presses.

Fig.1

eine Prinzipskizze einer erfindungsgemäßen Vorrichtung in der Frontansicht;

Fig.2

eine Prinzipskizze einer erfindungsgemäßen Vorrichtung In der Seitenansicht;

Fig.3

eine vergrößerte Detaildarstellung der in Figur 1 gezeigten Vorrichtung in der Frontansicht.

The invention allows for various embodiments. To further clarify its basic principle, one of which is shown in the drawing and will be described below. This shows in

Fig.1

a schematic diagram of a device according to the invention in the Front view;

Fig.2

a schematic diagram of a device according to the invention in side view;

Figure 3

an enlarged detail of the in FIG. 1 shown device in front view.

Fig. 1 shows a schematic diagram of a continuous press 1, for producing chip or fiber webs 2. The provided with a binder chip or fiber web 2 is for this purpose applied between a press drum 3 and a pressure roller 4 with a line pressure, which leads to the required density. In order to realize at the same time a consistent material thickness over the entire width of the chip or fiber webs 2 at the required density, the desired gap dimension "a" is first set by means of the serving as actuating means hydraulic cylinder 23 arranged driveable roller 4. During operation, the line pressure is detected continuously by means of pressure sensors 5 and the material supply is changed as a function of the determined deviations from a desired value until the line pressure reaches a desired value. The hydraulic cylinders 23 serving as actuating means can also be used independently of the pressure sensors in order to initially set a relatively large gap between the press drum 3 and the press belt 5 at the beginning of a continuous pressing of the fiber mat 2. Only when a mat leaves the pressing device again, the desired final pressure and / or the desired gap size with which the pressure roller 4 or the not shown very small rollers press in the direction of the main roller, set.

Fig. 2 shows a device 1 for the continuous production of chipboard or fiberboard 2, with a press drum 3 and a pressure roller 4. Between the press drum 3 and the pressure roller 4, a revolving press belt 5 is arranged, with which the chip or fiber plates 2 and the fiber fleece be pressed flat against the circumference of the press drum 3. In order to avoid an undesirable influence of impurities on the production process, cleaning agents 60 are applied with a cleaning device 6 substantially over the entire width of the press belt 5 against this. The nonwoven fabric 2 is conveyed via a conveyor belt 24 in the direction of the press entry, wherein in the region between the conveyor belt and the entrance, the nonwoven is supported by a transfer table 25. The table is tilted down towards the entrance.

Spaltmaßverringernde very ^- small rollers 21 press the press belt 5 against the press roller 3 and prevent springing of the compressed mat. In the upper area of the press, ie just before the pressed plate leaves the press, trimming rollers are provided, which finally bring the pressed plates to the desired dimension or correct deviations.

The exact operation of this cleaning device 6 is based on the Fig. 3 shown in detail, an enlarged detail of the in Fig. 2 shown device 1 shows. The cleaning device 6 designed as a brush is arranged on the outside on an endless carrier web 7, which can be driven circumferentially by means of a drive 8 transversely to the direction of movement of the press belt 5. The drive 8 and a bearing 9 of the carrier web 7 are common to one. Holding means 10 of the device 1 in different positions with at least two degrees of freedom adjustable. Serve for this purpose pneumatic cylinder 11, by which the holding means 10 according to the respectively detected by one of the two edge regions of the press belt 5 associated sensors 12 relative position and orientation of the press belt 5 is adjustable.

The cleaning device 6 in Fig. 2 and 3 can also act against the underside of the press belt 5 to eliminate in particular caked particles lying on the press belt

Claims (25)

1. Pressing device (1) for the continuous production of chip- or fiber-boards, wherein a chip- or fiber-mat (2) provided with a binding agent is subjected to a line pressure between a press drum (3) and a pressure roller (4), as well as, subsequently, to a surface pressure between a circulating press belt (5) and the press drum (3), wherein
   means (23) for setting the desired nip width between the press drum (3) and the pressure roller (4) and means for changing the supply of material of the chip- or fiber-web are provided,
   characterized in that
   a pressure sensor for acquiring the line pressure is provided.
2. Device (1) according to claim 1, characterized in that the press belt (5) is a circulating press belt, preferably a steel belt, by which the chip- or fiber-boards (2) can be pressed in a plane manner against the circumference of the press drum (3).
3. Device (1) according to claim 2, characterized in that a cleaning device (6) may get in contact with the press belt (5) essentially over its entire width.
4. Device (1) according to claim 3, characterized in that the cleaning device (6) is arranged at a carrier web (7) that can be driven in a circulating manner by means of a drive (8), essentially in a direction that is transversal to the direction of movement of the press belt (6).
5. Device (1) according to one of the preceding claims, characterized in that the mat (2) is introduced into the device (1) diagonally from above.
6. Device (1) according to one of the preceding claims, characterized in that the mat (2) is a pre-compacted mat.
7. Device (1) according to one of the preceding claims, characterized in that heating means for heating the device (1) are provided.
8. Device (1) according to one of the preceding claims, characterized in that a tension roller (20) is provided shiftably in such a way that the press belt (5) rolling off over the tension roller (20) can be tightened so that the desired surface pressure can be set by this.
9. Device (1) according to one of the preceding claims, characterized in that the tension roller (20) tightens the press belt (5) in a manner that a surface pressure of at least 25 N/cm², preferably at least 30 N/cm² can be achieved.
10. Device (1) according to one of the preceding claims, characterized in that the press drum (3), the tension roller (20) and/or the pressure roller (4) are heatable.
11. Device (1) according to one of the preceding claims, characterized in that very small rollers (21) are installed immediately downstream from the pressure roller (4), comprising a diameter of 300 to 450 mm.
12. Device (1) according to one of the preceding claims, characterized in that
    the device (1) is designed in such a way that, at the beginning of a continuous pressing of the mat (2), a relatively large nip width between the press drum (3) and the press belt (5) is set at first, and
    the device (1) is further characterized in that the desired final pressure and/or the desired nip width is set in that the pressure roller (4) or the very small rollers (21) press in the direction of the main roller, not until a mat (2) leaves the pressing device again.
13. Device (1) according to one of the preceding claims, characterized in that means (23) for continuous monitoring and correcting of the position of the press belt (5) are provided laterally relative to the direction of motion, such that a running out of the press belt (5) to the side is prevented.
14. Device (1) according to one of the preceding claims, characterized in that the means (23) for monitoring the position of the press belt (5) comprise mechanical and/or optical sensors.
15. Device (1) according to one of the preceding claims, characterized in that the means (23) for correcting the position of the press belt (5) comprise adjusting means (23) that act on at least one of the rollers, in particular on their axes.
16. Device (1) according to one of the preceding claims, characterized in that adjusting means are provided at several rollers, in particular at all rollers.
17. Device (1) according to one of the preceding claims, characterized in that an electronic control system is connected with the adjusting means such that the pressure roller can be pressed in a parallel manner against the main roller.
18. Device (1) according to one of the preceding claims, characterized in that a transport belt (24) is provided such that the mat (2) can be guided, by means of the transport belt (24) to the area from which the mat (2) is introduced into the press diagonally from above.
19. Device (1) according to one of the preceding claims, characterized in that between the transport belt (24) and the entry into the press, a transfer area (25) is provided that bridges the area between the transport belt (24) and the entry into the press.
20. Device (1) according to one of the preceding claims, characterized in that at the transfer area and/or above the transfer area, means for supplying vapor are provided which vaporize the mat (2).
21. Device (1) according to one of the preceding claims, characterized in that means (60) for treating the rollers and/or the press belt (5) are provided.
22. Device (1) according to one of the preceding claims, characterized in that the device (1) is adapted in that, at first, a desired nip width between the press drum (3) and the pressure roller (4) is set, and subsequently, the line pressure that determines the raw density is set by a change in the material supply of the chip- or fiber-web.
23. Device (1) according to one of the preceding claims, characterized in that the device (1) is adapted in that one pressure sensor is allocated for each edge region at the side of the chip- or fiber-web.
24. Working method for the continuous production of chip- or fiber-webs, wherein a chip- or fiber-web provided with a binding agent is subjected to a line pressure between a press drum (3) and a pressure roller (4) and additionally, to a surface pressure between a circulating belt (5) and the press drum (3), in order to generate a desired raw density,
    characterized in that
    at first, a desired nip width between the press drum (3) and the pressure roller (4) is set, and subsequently, the line pressure that determines the raw density is set by a change in the material supply of the chip- or fiber-web, wherein the line pressure is detected by means of a pressure sensor.
25. Working method, according to claim 24, characterized in that one pressure sensor is allocated for each edge region at the side of the chip- or fiber-web.

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