EP1782933A2 - Process and installation for producing sheet materials in a continuously operating press - Google Patents

Abstract

The method involves pressing and hardening the material plates by the use of pressure and heat. A cross cut is made running over the width of pressed material mat (9) before the continuously operating press (7). The end of the pressed material mat is always delivered to the continuously operating press with the linear edges perpendicular to the travel direction. An independent claim is also included for equipment for implementing the method.

Description

The invention relates to a method for producing material plates with a continuously operating press according to the preamble of claim 1 and to a system for carrying out the method according to the preamble of claim 14.

Particleboard and the production of material plates from, for example, medium-density fibers are now automated processes and are already being used in many countries for many years. As in " Wood materials, production and processing "by Hansgert Soiné, DRW-Verlag 1995, pages 17ff described the compression of processed chips or fibers takes place either clock bound or continuously. In addition to the many plant components before and after the press, the production of a pressed material mat by means of spreading machines plays an outstanding role, since the quality of the pressed food mat created is an important factor in addition to the quality of the raw materials.

For the large-scale production of wood-based panels, continuous presses are used. In these presses, as in DE 39 13 991 C2 described, the pressing force is transmitted by hydraulic actuators on the press and heating plates and further on steel belts, which are supported by a rolling element carpet (rolling rods) circumferentially arranged on the pressed material. In the case of the abovementioned transmission elements, the steel strips with thicknesses of approximately 1.5 to 4 mm form the weakest component in the chain of failure-threatening machine elements compared to the other, substantially stiffer elements. In this context, it does not mean that the steel strip fails completely, but should the surface of the steel strip damage it already leads to a poor surface quality of the final product and thus to rejects. Due to the production of increasingly thinner and above all highly compressed wood-based panels, the deformation work to be performed increases with partial differences in density of the material to such an extent that even very small-scale density fluctuations, for example by fiber balls or glue lumps in the pressed material to pressure points on the surface of the steel strip or even destruction lead the steel strip.

The production of a Pressgutmatte, also called form strand, done by scattering the treated material on a forming belt by means of spreaders, then followed by a control of the pressed material mat by means of a basis weight scale and / or a density control. Usual are further Magnetic separators and search coils as metal detectors, prepressing for precompression, trimming of the longitudinal sides of the pressed material mats and before a cycle press a necessary Mattenvereinzelung. Thereafter, it is state of the art to arrange a Fehlchargenschacht or junk bunker to unfavorably scattered or sprinkled with faulty material Pressgutmatten before the press inlet quickly and safely remove from the mold string and prevent compression. The underlying idea is actually to save raw materials, because from the disposal bunker, the materials used are usually reintroduced into the raw material processing and used again at the next opportunity.

As in " Wood-Based Panels, Production and Processing "by Hansgert Soiné, DRW-Verlag 1995, page 72 shown and described in Fig. 118, a pre-compacted pressed material mat during the ejection of the forming belt across the width breaks piece. The fracture behavior of the pressed material mat in the incorrect batch discharge or above the discharge bunker is understandably dependent on the pre-compaction, on the type and dispersion of the material used, the type of adhesive other factors. It is crucial that even with a compacted non-woven mat a lumpy canceling is common and known. Depending on the material, it may even over the width of Pressgutmatte come to breakage, so that usually no straight break edge is formed, but a more or less jagged, which may have pointing in the direction of production peaks.

In start-up operation after the start of production or during a product change, in which a continuously operating press usually only has to be emptied, all individual parts of the system are first started up at idle, all parts of the plant before the continuously operating press to work with material. Accordingly, a pressed material mat of scattered material forms on a forming belt, which is disposed of continuously in a discharge bunker. The discharge area remains open until all necessary other parts of the system are in proper operation. It is also important for the continuous press, that the mold weight of the scattered Pressgutmatte is properly adjusted, the continuously operating press with the correct parameters preset and operating temperature and the final production (format separation, cooling station, deposition) after the continuous press ready for is the exiting plate strand. If the consistency of the press mat is suitable, the transfer nose moves from the discharge position in the production direction and bridges the discharge chute to the transfer point of the press mat to the lower steel strip of the continuously operating press.

It sometimes happens now that with an irregular breaking edge of the pressed material mat, the protruding tips cause distortions or partial densifications in the pressed material mat during the inlet into the continuously operating press. Due to irregular rupture edges, incalculable flows of escaping air or steam are also created Infeed wedge of the continuously operating press, wherein these flows are able to move parts of the material to be pressed against the direction of production and thus increase the density drastically in partial areas. These detrimental effects can lead to duplications of the pressed material mat in the inlet region, whereby partial overpressure loads on the elements transmitting the pressing pressure arise in the press nip of the continuously operating press. As a rule, surface damage of the steel strips occurs first.

Defective surfaces of steel belts of a continuous press are harmful for the surface quality of the product, on the one hand, and on the other hand, the steel belts are sometimes the most expensive parts of a continuous press and cause a long production loss with each replacement.

In addition to the above-mentioned problems during the start-up operation, it may be necessary during production to open the discharge bunker in order to dispose of parts of the pressed material mat. This is necessary, for example, in the case of metal detection in the pressed product mat, in the case of defective fillings by the spreading machines or in the event of problems in the production of the pressed product mat. This can happen that the pre-compacted pressed material mat initially continues to break without interruption in the continuously operating press and bridged by their internal affinity of the material, the discharge area for seconds. This can be done with a fast running production Feed of over one meter per second. In the case of foreign bodies in particular, despite early detection, this can still lead to shrinkage of the same in the continuously operating press and damage to the steel bands.

The conversion of production in width or thickness of the material plates may also be a reason to interrupt the pressed material mat and to empty the continuously operating press.

Until the parameters of all system parts, eg. As material dryer and classification range of the material before the continuous press and the final production after the continuous press such as trimming, cooling stars, grinders and maturing, are matched to each other again, it does not make sense to produce panels that sawed as scrap and cumbersome disposed of must be, but the scattered Pressgutmatte is disposed of in the discharge bunker and fed the material for recycling. Especially a product change with change of the glue and / or the litter material itself can take a long time due to the long conveying path of the material to be spread from the material bunkers.

The invention has for its object to provide a method for the production of material plates with a continuously operating press, in which the steel strips and other machine elements are protected by the incalculable run-in behavior of crushed pressed material mats and a Specify an installation for carrying out the method, with which it is possible to prevent damage to the steel strips occurring through the entry of irregular press material mat edges across the width.

The solution for the method according to the invention consists according to claim 1 in that before the continuously operating press over the width of the Pressgutmatte running separating cut is performed to pass existing ends of a pressed material always with straight edges transverse to the transport direction to the continuous working press.

The solution for a plant for carrying out the method according to claim 14, consists of one or more scattering stations, with associated forming belt, subsequent monitoring devices of Pressgutmatte, a pre-press, a discharge bunker and a continuously operating press in the direction of production before a continuously operating press for the pressed material one or more separation devices are arranged over the production width.

Thus, for example, in the starting operation across the width of the pressed material mat running separation cut are performed, the pressed material until the separation cut continues to be disposed of via the discharge bunker and the forming belt after dropping the pressed material until the separation cut with the Übergabase bridges the discharge bunker and so the Pressgutmatte to the continuous working press with a rectilineal press mat edge. In the case of a fault or a production change, a separating cut is also carried out, in which case the straight-line separating cut at the end of the incoming pressed material mat should facilitate the transition from production to idling. Also, the discharge behavior of the pressed material mat when opening the discharge bunker is improved.

In an alternative, it is possible to carry out the separating cut after the discharge bunker on the intermediate belt arranged between the forming belt and the continuously operating press. Since here no discharge bunker is available directly in the direction of production, the excess Pressgutmatte must be either sucked off or pushed down from the intermediate belt. The suction device can either be arranged along with the separating device or fixed over the entire width of the pressed product mat and is mounted according to the start-up or shut-down operation in or against the production direction to the separation device.

Preferably, the separating cut is carried out by means of cutting rotary tools such as milling or sawing. It makes sense not to perform the separation cut completely by the scattered Pressgutmatte, but at a predetermined safety distance to each lying below the forming or intermediate band, so this can not be damaged. Alternatively, the separating cut be carried out by means of a arranged over the entire width lowerable cutter bar.

The separating cut of the separating device is carried out perpendicular to the Pressgutmattenlängskante. This is to facilitate the outflow of excess air inclusions in the inlet wedge of the continuously operating press. Because the outflow behavior of the pressed material mat in the inlet or in the wedge compressor of the continuously operating press is an important criterion and also influences the maximum production speed.

Advantageously, the present method is applicable in the production of thin MDF or HDF material plates below 5 mm, being driven with a forming belt or a production speed of 700 to 2500 mm / s.

The separation cut is not limited to the implementation of a narrow slit by means of a dicing saw, but two cuts can be introduced at a predetermined distance in the pressed material mat. The distance is chosen so that between the two separating cuts 40 mm to 1200 mm are available. In this case, the pressed material mat between the two separating cuts either sucked off or pushed down from the forming belt. This variant is useful at high feed speeds or high production speed, so that the control technology control of the retracting Übergabease also safe the Separation cuts and not on incorrect control of the cut edge destroyed and thus a broken Pressgutmattenkante enters the press, either at the beginning of a new production or at the end or an emergency discharge of Pressgutmatte in the discharge bunker.

Further advantageous features, measures and embodiments of the subject matter of the invention will become apparent from the dependent claims and the following description with the drawing.

Figur 1

In Draufsicht schematisch die Anordnung der Anlagenteile zur Herstellung des Formstranges mit der erfindungsgemäßen Anordnung von Trennvorrichtungen vor einer kontinuierlich arbeitenden Presse und

Figur 2

in schematischer Seitenansicht eine vergrößerte Ansicht einer Anlage nach Figur 1 von der Vorpresse bis zur kontinuierlich arbeitenden Presse, welche beispielhaft als Doppelbandpresse dargestellt ist.

Show it:

FIG. 1

In plan view, the arrangement of the system parts for producing the molded strand with the inventive arrangement of separation devices in front of a continuously operating press and

FIG. 2

in a schematic side view of an enlarged view of a plant of Figure 1 from the pre-press to the continuously operating press, which is exemplified as a double-belt press.

As shown in the two figures, a Pressgutmatte 9 is scattered by means of one or more scattering machines 1 on a forming belt 8 and thereby guided continuously in the production direction to the continuously operating press 7 out. The scattered Pressgutmatte happens while a Formbelwaage 2 for Examination of the spreading quality of the spreading machines 1 and a pre-press 3 for precompression of the pressed material mat 9. The pre-press 3 can also take over other functions such as temperature and humidity calibration. After the pre-press 3, the pre-compacted pressed material mat 9 is examined with a metal detector 4 for foreign bodies. Here also a radiation of the. Pressgutmatte 9 or any other suitable method of investigation are used to detect high-density non-metallic foreign bodies such as glue lumps in the spreading material 9 of the pressed material. Subsequently, the pressed material mat 9 passes through a separating device 5 and the discharge area 18 of the discharge bunker 6. During production, the discharge area 18 or the discharge bunker 6 is bridged by means of the transfer nose 16 and the forming belt 8. In general, between the forming belt 8 and the continuously operating press 7, there is still an intermediate belt 19 which transfers the pressed goods mat 9 to the continuously operating press 7. There, a material plate is pressed using pressure and heat from the Pressgutmatte 9. This is done in the present drawing by means of a continuously operating press 7, designed as a double belt press with top and bottom arranged endless rotating steel belts 11 which are guided around idler pulleys 10. For rolling support of the steel strips 11, a roll bar circulation 12 is arranged between the heated pressing plates 13 and the steel strips 11. Of course, instead of the continuous press 7 and a calender (not shown) can be used. The respective continuous press is followed by a final production (not shown). If it is decided during production to open the discharge bunker 6, the separating device 5 comes into action and performs a separating cut across the width of the pressed product mat 9. This separating cut ensures that a straight cutting edge of the pressed material mat 9 enters the continuously operating press 9, while the subsequent parts of the press material mat 9 fall properly during the process of the transfer nose 16 in the discharge position 14 on the baffle plate 17 and then in the discharge bunker 6. There, the Pressgutmatte 9 is divided or broken and recycled.

Even during start-up operation, during the continuous disposal of the pressed material mat 9 by the discharge bunker 6, a separating cut is carried out by the separating device 5 in preparation for the production. The transfer nose 16 stands in discharge position 14 and is moved over the path k in the direction of continuously operating press 7 to the transfer position 15 when the straight cut edge of the pressed material mat 9 has reached the transfer nose 16. The driving speed of the transfer nose 16 is equal to or greater than the current feed of the forming belt 8. Thus, a straight cutting edge is retracted into the continuously operating press 7 and it is avoided that by blown or Mattendopplungen damage to the steel belts in startup, the production change or can occur in case of failure.

In an extended embodiment, either instead of or in addition to the separator 5 above the forming belt 8 a Separating device 20 may be arranged on the intermediate belt 19. In this case, it should be noted that in the case of a separating cut on the transfer belt, no discharge bunker 6 is no longer available in the production direction. For this reason, the excess parts of the Pressgutmatte 9, which should not retract into the continuous press 7 are otherwise disposed of, for example, by suction or pushing away. In FIG. 2, suction units 21 are arranged on both sides of the separating device 20 for this purpose, which provide for the removal of the excess parts of the pressed material mat 9. It can also be arranged only one foldable over the separator 20 suction unit 21, which is folded as required at a separation cut at the beginning of a retractable Pressgutmatte 9 in the production direction after the separator 20 in the direction of continuously operating press 7 and for a separating cut at the end of the retracting Pressgutmatte 9 is folded to the other side of the separator 20. Preferably, during production, the suction unit 21 will be arranged to wait as described last to be ready for an emergency separation cut. In the starting operation, however, stands the suction unit 21 between separator 20 and continuously operating press 7 to 18 after extraction of the discharge area to pick up the irregular incoming Pressgutmatte 9 to carry out the separation cut.

With fast-running thin-plate production of less than 5 mm, the extraction of the material plates at a feed rate of more than 1000 mm / s lends itself to suction because here the pressed-material mat 9 is in the vicinity of the pressing continuously working press 7 not too thick and a suction can be successfully practiced. Due to the close arrangement of the separating device 20 to the continuously operating press 7 towards a longer distance between the metal detector 4 after the pre-press 3 and the separator 20. Thus, in fast-running productions up to 2500 mm / s more than a second is slightly more than a second Time to activate the separator 20 with suction units 21 to dispose of hazardous Pressgutmattenteile. As already described, when the ejection region 18 is opened in the case of an emergency ejection, the press material mat 9 at high feed speed before it breaks off and falls into the ejection bunker 6 still spans the ejection region 18 for some time due to internal stress. Especially with high-speed presses could thus foreign objects reach the continuously operating press 7 and cause damage.

LIST OF REFERENCE NUMBERS

1. 1. spreading machine
2. 2. Form belt scale
3. 3. Prepress
4. 4. Metal detector
5. 5. Separator
6. 6. Dump bunker
7. 7. continuously working press
8. 8. Form band
9. 9. Pressed material mat
10. 10. tail pulley
11. 11th steel band
12. 12. Rolling rod circulation
13. 13. heated press plates
14. 14. Dropping position
15. 15th transfer position
16. 16th handover nose
17. 17. baffle plate
18. 18. Drop area
19. 19th intermediate band
20. 20. Separator
21. 21. Suction units

K

Way between transfer and discharge position

Claims (20)

Method for producing material plates with a continuously operating press, wherein a pressed material mat, consisting of chips, fibers, chips or the like scattered on a forming belt, after the scattering and production-dependent pretreatments, is pressed and hardened in a continuously operating press using pressure and heat is, wherein before the continuously operating press unusable or harmful to the operation parts of the pressed material mats are disposed of continuously, characterized in that
Before the continuously operating press, a separating cut running across the width of the press mat is carried out in order to transfer existing ends of a press mat always with straight edges transversely to the transport direction to the continuous working press. A method according to claim 1, characterized in that in the manufacture of thin MDF or HDF material plates under 5 mm thickness, with a forming belt or a production speed of 700 to 2500 mm / s is driven. Process according to claims 1 or 2, characterized in that the excess or dangerous Pressgutmattenteile be sucked in the preparation of the separating cut. Process according to claims 1 or 2, characterized in that the excess Pressgutmattenteile fall after the preparation of the separating cut in a discharge bunker. Method according to claims 1 to 4, characterized in that the separating cut is carried out perpendicular to the pressed material mat longitudinal edge over the width of the production direction. Method according to claims 1 to 6, characterized in that the separating cut is carried out by means of cutting rotary tools. Method according to claims 7 and 8, characterized in that the separating cut is carried out with a predetermined safety distance to the forming belt or intermediate belt. Method according to one or more of the preceding claims, characterized in that the separating cut is carried out in front of the discharge bunker on the forming belt. Method according to one or more of the preceding claims, characterized in that the separating cut is carried out directly in front of the continuously operating press on the intermediate belt and at the same time the excess mat parts are sucked off. A method according to claim 1, characterized in that the separating cut is carried out on the forming belt by means of a arranged over the entire width lowerable cutter bar. A method according to claim 1, characterized in that two separating cuts are introduced at a predetermined distance in the pressed material mat. A method according to claim 13, characterized in that the distance between the two separating cuts is 40 mm to 1200 mm. Method according to claims 10 or 11, characterized in that the pressed material mat is either sucked off or pushed down from the forming belt between the two separating cuts. Plant for carrying out the method according to claim 1, comprising one or more scatter stations (1), with associated forming belt (8), monitoring devices of the pressed material mat (2, 4), a pre-press (3), a discharge bunker (6) and a continuously operating one Press (7),
characterized in that one or more separation devices (5, 20) are arranged over the production width in the production direction in front of a continuously operating press (7) for the pressed material mat (9). Installation according to claim 14, characterized in that the continuously operating press (7) either consists of a calender or a double belt press with two rotating steel belts. Plant according to claims 14 and 15, characterized in that for the production of the separating cut above the Forming band (8) a separating device (5) is arranged. Plant according to claims 14 and 15, characterized in that a separating device (20) is arranged to produce the separating cut above the intermediate strip (19). Installation according to claims 14, 15 and 17, characterized in that suction units (21) are arranged next to the separating device (20). Installation according to claim 18, characterized in that the suction units (21) are arranged stationary over the entire width or locally along the separation device (20). Plant according to claims 14 to 18, characterized in that one or more diagonal saws are arranged as separating device (5, 20).

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