EP2504135A1

EP2504135A1 - System and method for forming a mat of dispersed material from dispersed material on a form belt in the course of the production of material plates

Info

Publication number: EP2504135A1
Application number: EP10784710A
Authority: EP
Inventors: Gernot Von Haas
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2009-11-25
Filing date: 2010-11-25
Publication date: 2012-10-03
Anticipated expiration: 2030-11-25
Also published as: CN102770250A; DE102009047125A1; CN102770250B; WO2011063966A1; EP2504135B1; PL2504135T3

Abstract

The invention relates to a system and method for forming a mat of dispersed material (1) on a form belt (10) in the course of the production of material plates by means of pressure and/or heat in a press, a dispersion device (3) being arranged over the form belt (10) in the direction of fall (11) and, in order to supply the dispersion device (3) with dispersed material (1), a metering device (2) being arranged before the dispersion device (3) in the direction of fall (11), and a fall duct for the transport of the dispersed material (1) being arranged therebetween. The invention proposes, in order to receive excess air and/or air (5) accelerated by the dispersed material (1) from the fall duct (4) and/or the dispersion device (3), that a compensating air duct (6) is arranged integrally or separately from the fall duct (4), that the opening (16, 31) of the compensating air duct (6) on the inlet side is arranged to be operatively connected to the fall duct (4), substantially on the outlet side, and/or to the dispersion device (3), and that, in order to form a substantially circular flow of the air (5), the opening (15, 26, 32) on the outlet side of the compensating air duct (6) is arranged to be operatively connected to the metering device (2) and/or to the fall duct (4) substantially on the inlet side, and in that guide means (8) for controlling the flow of the air (5) are arranged in the compensating air duct (6).

Description

Plant and method for forming a scattering mat of grit on a forming belt in the course of the production of material plates

The invention relates to a system for forming a grit mat from free-flowing material on a forming belt in the course of the production of material plates according to the preamble of claim 1 and a method for forming a grit mat from grit on a

Forming tape according to the preamble of claim 11. The production of material plates (MDF, LDF, HDF) from, for example, medium-density fibers or other free-flowing materials are now automated processes and are already used in many countries for years. As is known, 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 spreading material mat by means of spreading machines plays an outstanding role, since the quality of the produced spreading material mat 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 described in DE 39 13 991 C2, the pressing force by hydraulic actuators on the press and heating plates and further on steel belts, supported by a Wälzkörperteppich (rolling rods) circulating are arranged, transferred to the grit. Such presses

process usually glued spreading material that has been formed in spreading machines to a flat grit mat on a continuously moving forming belt.

From DE 103 04 147 A1 discloses a device for spreading of grit on a continuously moving forming belt has become known. In this

Revelation is proposed, the spreading material dosed from a

Discharge hopper by means of an array of opening rollers to ensure a reasonably even distribution and complete resolution of coagulation across the width. After a task flap or directly from the dosing hopper, the dissolved chips fall on a scattering roller assembly and are there scattered over several scattering rollers on the continuously moving forming belt to form a grit mat. The device according to this disclosure has proven itself in principle and has made possible across the width

sufficiently uniform basis weight profile.

For example, from DE 10 2006 030 122 B4 a grit system has become known, which between the dosing bunker and a

Scattering device provides a chute in which distributed over the width of the air flow distributing the spreading material distribution in a first wall of the chute distributed over the wall width adjustable air supply means are provided with in one opposite second wall one or more adjustable Luftabführeinrichtungen. Thus, there is the possibility of controlling the spreading material distribution or the basis weight across the width with the aid of air flows which are introduced directly into the falling spreading material. This approach is promising at first glance, but has many disadvantages during operation.

In a narrow chute in the production direction, for example, not only scattered material is displaced by the short air flow, but also a certain amount of grit by means of the air flow in the

Air discharge facilities discharged. Any grille clogs in the mass flow in no time and prevent the

proper operation of the device. If the chute is carried out correspondingly deeper (in the production direction of the forming belt), incalculable turbulence and entrainment effects arise, since the grit is free to move in all directions while falling and is more susceptible to pneumatic, in particular for, self-induced by the fall movement, air currents. It has now been shown that end customers or customers of the material plates produced direct new specific demands on the material plates, especially in the production of MDF boards made of medium-density fibers to the producers. These requirements include, for example Different basis weight profiles across the width to create different zones of different basis weights for MDF boards, for example. This can be done while minimizing the basis weight

Weight minimization and material saving serve or at a

Maximizing the weight per unit area or, for example, for the edge protection or the attachment of fittings may be useful.

In the case of pulsed influencing, a basis weight profile can be set transversely to the production direction, for example in such a way that during the later division of the material plates after pressing, a separating cut is preferably made in the higher basis weight ranges, so that the cross sections also result in a higher edge density on the divided plates ,

The object of the invention is to provide a method and a system, at least consisting of a forming belt, an overlying scattering device and an associated metering device, in which the scattering quality influencing air flows respectively

Air turbulence or an air accumulation before or avoided in a scattering device or compensated sufficiently and with simple means a differentiated basis weight of the scattering mat to be scattered across the width and / or in the production direction of the forming belt during operation should be einsteuerbar. The solution for the system according to claim 1 is that the

Receiving excess and / or accelerated by the grit accelerated air from the chute and / or the spreader integrated or arranged separately to the chute a compensation air shaft,

that the input-side opening of the compensation air shaft with the chute essentially on the output side and / or with the

Scattering device is arranged operatively connected, that is arranged to form a substantially circular flow of air, the output-side opening of the compensation air shaft with the metering device and / or with the chute substantially operatively connected input side and

that guide means for controlling the flow of the air are arranged in the compensation air duct. The solution for the method is that excess and / or accelerated by the grit air from the chute and / or the spreader integrated or separately added to the chute by means of an input-side opening of a compensation air duct, the output shaft with the chute and / or is operatively connected to the spreader,

in that, for the purpose of forming a substantially circular flow of the air, the outlet-side opening of the compensation air shaft feeds the air to the metering device and / or substantially on the input side to the chute passes and

that in the compensation air shaft, the flow of air by means

Guiding means is controlled or regulated in order to influence or adjust the basis weight profile over the width and / or in the production direction.

In contrast to the known method is preferably not actively intervened in the air currents in the chute, but the air swirling opportunity is given in a preferably larger

Compensating air shaft to relax. An active suction can be dispensed with in an advantageous manner, which also avoids an otherwise necessary filtering of the extracted air, as this is easily returned to the production cycle. On the merits, it is nevertheless the case that in some cases an air exchange takes place in the entire system with the environment. Should this be due to the resulting

circular circulation cause the air within the system to become overdamped with dust / moisture / pollutants, the air returned in the compensation shaft can be replaced evenly or at regular intervals with fresh ambient air. Preferably, the used air and possibly with fine dust and / or binder contaminated air in a thermal converter is aftertreated and cleaned. The downcomer respectively the equalizing air duct has an inlet and an outlet end or opening, wherein the terms on the inlet and outlet side refer to the fluids conveyed therein / moved and / or

Material, here grit, relate. For example, the input-side end of the chute with the metering device and the output end of the chute is connected to the spreader. Correspondingly, the inlet-side opening of the compensation air shaft with the scattering device is then preferably arranged substantially adjacent to or adjacent to the outlet-side opening of the chute. Under adjacent is to be understood that the input-side opening of the compensation air duct is located directly on the output side opening of the chute, adjacent would be understood an unspecified distance between the two openings, the excess air or any air accumulation still occurring the Tendency to escape into the compensation air duct instead of wandering in the direction of the forming belt in the scattering device.

By simple means is now avoided that an air accumulation leads by the falling grit from entrained and accelerated air turbulence in the scattering device to scattering material displacements on the forming belt. In further preferred embodiments, in

Compensation duct guide means for controlling the flow of air to be arranged. These can be active and / or passive for the control of the air, wherein as active guide means fans or injection nozzles for the air in question and / or as a passive guide

Flow resistances such as rods, sieves, perforated plates and / or baffles are arranged. In this case, at least one guide means should be arranged to be movable by means of an adjusting device, preferably for changing the position and / or the area of action in the compensation air shaft. Furthermore, in a combined or separate variant, it is conceivable that at least in part of the compensation air shaft at least one partition wall is arranged across the width of the forming belt and / or in the production direction of the forming belt for dividing the cross section of the compensation air shaft. Alternatively, of course, several

Balancing air ducts may be arranged. The partition should be arranged to be movable by means of at least one adjusting device, preferably substantially transversely to the production direction. Preferably, one or more partitions at least partially divide the compensation air duct into partial air ducts, wherein essentially the partial air ducts

influencing guide means, preferably separately for each

Partial air shaft, are arranged. It is also conceivable that at least parts of the compensation air shaft with a larger cross section than the chute and / or that to change the cross section of the

Ausgleichsluftschachtes and / or the chute, at least one

Adjusting device is arranged. The larger cross-section is preferably arranged on the input-side opening of the compensation air shaft, so that the excess air due to the flow gradient preferably evades into the compensation air shaft. For entrained grit or dust may be in the balance shaft at least one

Separating device may be arranged. For a compact space, the compensation air shaft is substantially parallel to the chute.

Further advantageous measures and embodiments of the subject matter of the invention will become apparent from the subclaims and the following

Description with the drawing out. Show it:

Figure 1 is a schematic side view of a system for forming a

Grit mat from spreading material on a forming belt in the course of the production of material plates by means of a in

Production direction, not shown press, wherein the metering device is arranged as a dosing bunker with a discharge device above a spreader and a chute with an associated compensation duct connects these two parts of the plant,

Figure 2 shows a possible variant of the arrangement of a

Balancing duct between metering device and

Spreading device, Figure 3 shows another possible variant of the arrangement of a

preferably adjacent to the chute or integrated

Compensating air shaft,

Figure 4 is a sectional plan view through a chute and the associated compensation air shaft of Figure 1 with representation of a conceivable setting of the air currents for setting a basis weight profile across the width of the forming belt, Figure 5 is a vertical section across the width of a manufactured

Spreading mat on a forming belt with reference to the sectional plan view of Figure 4 with an exemplary representation of a

Basis weight profile with outside spills and

6 shows a sectioned section of Figure 1 with representation of a guide means for influencing the flow of air in the compensation air shaft.

Figure 1 shows a schematic side view of a system for forming a grit mat 25 from free-flowing material 1 on a forming belt 10 in the course of the production of material plates by means of a in

Production direction 23 arranged, but not shown press. The dosing device 2 is designed as a dosing bunker with a discharge device above the spreader 3. The dosing bunker has on the input side at least one side wall 22 and a backscrap rake 21 above a bottom belt 19, which sweeps back the grit 1 entering the dosing hopper on the bottom belt 19 to a Schüttberg. During discharge, the Schüttberg from spreading material 1 is controlled by means of the bottom belt 19 against the discharge device, here discharge rollers 20, moved and it is thus achieved a uniform discharge of the material to be spread 1 in the chute 4. The discharge rollers 20 are usually designed as spiked rollers and loosen the grit 1 in addition. For this reason, as a rule, a kind of falling material flow of grit 1, in which a not definable amount of air 5 entrained, transported and thus accelerated. The transition from the chute 4 into the spreader 3 can be determined fluently or unambiguously. This depends on the geometric dimensions of the individual and cooperating system parts

Chute 4 and spreading device 3. In the present example, for example, the side wall 28 forms not only a part of the chute 4 but also a side wall 28 of the spreader 3. After the

Passing from the chute 4 in the scattering device 3 forms the grit 1 on the scattering rollers 24, which constitute a scattering roller carpet, a grit carpet 27 and it comes here to an air storage. This usually leads to turbulence of the air, which also by the

Spreader rollers 24 pass through in parts and then even during the fall of the grit 1 in the direction of fall 11 on the forming belt 10 to shifts the grit 1 in or across the Production direction 23 and thus within the grit mat 25. This air accumulation or turbulence usually occur irregularly or periodically and significantly reduce the quality of the scattering of the scattering device 3. By the adjacent arrangement of an opening 16 of a

Compensating air shaft 6 in the area of the air accumulation will be the

Excess air 5 makes it possible to take the path of the least resistance and can change over to the compensation air shaft 6. In particularly high-quality systems, as shown in the example, the cross section of the chute 4 and / or the compensation air shaft 6 can now at least partially by means of suitable adjusting devices to the

Throughput of grit per unit time to be adjusted.

Here, for example, the side wall 28 can be moved by the not shown in detail and stylized by means of a double arrow actuator 30 to change the cross section of the chute 4. Also one

Angle adjustment of the side wall 28 is conceivable, especially at

Side walls which are arranged at an angle to the direction of fall 11 and thus form a kind of slide.

Another variant of the cross-section adjustment would be, for example, in a combined arrangement of the chute 4 with the

Ausgleichsluftschacht 6 by adjusting one or more common partition walls 18 by means of a suitable adjusting device 29. Additionally or alternatively, the outer side wall 14 of

Ausgleichsluftschachtes 6 by means of at least one adjusting device 17th be arranged at least partially movable.

The output-side opening 15 of the compensation air shaft 6 is here above the discharge, respectively the discharge rollers 20, arranged on the metering device 2 and transfers the excess air 5 back towards the chute 4 to the metering device 2. This allows a circular circulation flow through their

mutual fluid-mechanical dependencies is supported.

For example, the air 5 from the opening 15 of the

Compensating air shaft 6 attracted by the falling grit 1, which in turn for a metrologically difficult to detect negative pressure in

Compensation duct 6, in particular in the region of the opening 16, which in turn improves the absorption of the stagnant air 5 from the chute 4 and the spreader 3. In Figure 2 is a possible variant of the arrangement of a

Ausgleichsluftschachtes 6 between metering 2 and

Scattering device 3 is arranged, wherein the essential system parts are designed as shown in FIG. The compensation air duct 6, however, is arranged on the output side to the chute 4, wherein the opening 31 of the compensation air duct 6 partially overlaps with the chute 4 and partially with the spreader 3. Again, a circular circulation of the air 5 is possible if it is introduced directly at the opening 26 on the side wall 22 in the metering device 2. In particular, in the direction of fall 11 angled Ausgleichsluftschächten 6, it is advisable to arrange a separator 39 for dust or grit 1. Again, 6 adjusting devices 17 are arranged on the side wall 14 and the movement of the side wall 28 of the chute 4 actuators 30 again to the cross-sectional change of the compensation air shaft. Advantageously, in the present

Embodiment, the basis weight distribution of the material to be spread already be influenced in the metering device 2 itself. For influencing the basis weight distribution by means of the guide means, it is explained in greater detail with reference to FIG. 4ff.

Figure 3 shows yet another possible variant of the arrangement of a preferably adjacent to the chute 4 or integrated

Ausgleichsluftschachtes 6 with a receiving opening 31, wherein the circular circulation does not include the discharge of the Austragswalzen 20, but directly between chute 4 and

Compensation duct 6 plays. The return of the air 5 in the

Chute 4 is in this case carried out via the opening 32, which is arranged directly on the input side of the chute 4. Depending on the design or geometric arrangement of the opening 32 and the transition to the chute 4 can also be on the Venturi principle, a negative pressure in

Balancing duct 6 are set when the grit 1 in Fall direction 11 falls past this opening 32 while air 5 pulls out of the opening 32 out.

Figure 4 shows a sectional plan view through a chute 4 and the associated compensation air shaft 6 of Figure 1 with representation of several possible adjustment options of air flows through guide means for setting a basis weight profile across the width 36 of the forming belt 10. The proposed compensation air shaft 6 has for this purpose at least partially partitions 40th as a guide means, which may optionally be movable by means of suitable adjusting devices 41. This can be used, for example, to set the partitions 40 to one another, to move (parallel), in or out of the

Ausgleichsluftschacht 6 to move or a kind of compartments in

Passage direction of the air 5 set a. In these individual

Partial shafts are arranged guide means 8, which can change the cross section targeted across the width 36. Here is exemplified that the flow of air in the outer part shafts through far

retracted guide means 8 is more obstructed than in the inner part shafts. This is particularly indicated by the marked areas of action 38 of the guide means 8 on the cross section 7 of the compensation air shaft 6. By this obstruction of the air is achieved that seen over the width 36 in the middle of an oversupply of air 5 during the passage of air from the opening 5 occurs in the chute 4. Through the physical endeavor same air and To obtain pressure conditions, enters a cross-flow 34 of the air, which leads from the center in the direction of the outer sides.

With reference to FIG. 4, FIG. 5 illustrates the effect of this transverse flow 34, through which more or less spreading material 1 is reinforced in the direction of the flow

Outsides is moved. This circumstance means that the height of the grit mat 25 will be substantially higher on the outside than in the middle of the grit mat 25. This may be particularly desirable if, after pressing by means of a press on the outside

Fittings for furniture to be installed or attached or edge banding should be applied. Also results in the further handling of a more robust plate, which is particularly advantageous for large format plates to the division. It is known to those skilled in the art that despite the different height of the incoming grit mat in the press a uniformly thick material plate is produced, which may have a higher density on the outside.

Analogously, these surface weight shifts can also be carried out the other way round or these surface weight shifts can be used to correct and compensate scattering errors caused by the metering device and / or the scattering device itself.

In summary, therefore, results in the illustrated vertical section across the width of a manufactured grit mat 25 on a forming belt 10 the exemplary representation of the basis weight profile over the width 36 with outside scattering heights of a height 35th

FIG. 6 shows a sectioned and enlarged partial detail according to FIG. 1, showing a guide means 8 for influencing the flow of the air 5 in the compensation air shaft 6. The guide means 8 can be moved in the compensation air shaft 6 by means of the adjusting device. The entering area of action 38 shows the obstruction of the air 5 or the flow velocity or the flow volume, represented with the two arrows of different size for the air. 5

Preferably, the partial air shafts or the partitions at a distance of 200 to 500 mm from each other. The chute should, depending on the particle size, preferably at DF, be 100 to 300 mm long in the direction of production. The compensation air duct is preferably 200 to 700 mm long in the production direction. The (total) width of the air ducts is preferably always as wide as the scatter or the

Case width.

Advantageously, accelerated and pent-up air in the spreading device, preferably above a scattering roller arrangement, can now be diverted by predefining the dynamic pressure with a favorable evasion solution. 1397 List of numbers 1397:

Grit 22. Sidewall of 2

Dosing device 23. Production direction

Spreading device 24. Dispersing rollers

Chute 25. Grit mat

Air 26th output side opening of 6

Compensating duct 27. Grit carpet on 24

Cross section 28. Sidewall of 4

Guide means 29. Adjusting device for 18

30th adjusting device for 28

, Formband 31. Entrance-side opening of 6th drop direction 32. Outgoing-side opening of 6. 33.

, 34. Cross flow of 5

, Sidewall of 6 35. Height of 25

, output side opening of 6 36. width of 25

, Input opening of 6 37. Adjusting devices for 8th adjusting device for 14 38. Effective area 8 in 6th intermediate wall 39. Separating device

, Bottom band 40. Partition walls

, Discharge rollers 41. Actuators for 40th back rake

Claims

Patent claims

System for forming a grit mat from grit (1) on a forming belt (10) in the course of producing material panels by means of pressure and/or heat in a press, with a spreading device (3) above the forming belt (10) in the falling direction (11) and to supply the spreading device (3) with spreading material (1) in the direction of fall (11) in front of the spreading device (3) a metering device

(2) and a chute (4) is arranged in between for the transport of the grit (1), so that there is no sign,

that to absorb excess and/or air (5) accelerated by the grit (1) from the chute (4) and/or the

Spreading device (3) is integrated or a compensating air shaft (6) is arranged separately from the chute (4),

that the input-side opening (16, 31) of the compensating air shaft (6) is essentially connected to the drop shaft (4) on the output side and/or to the spreading device

(3) is arranged operatively connected and that in order to form a substantially circular flow of air (5), the outlet-side opening (15, 26, 32) of the

Compensating air shaft (6) with the metering device (2) and/or with the drop shaft

(4) is essentially arranged in an operatively connected manner on the input side and

that in the compensating air shaft (6) there are guide means (8). Control of the flow of air (5) are arranged.

System according to claim 1, characterized in that active and/or passive guide means (8) are arranged to control the air (5).

System according to claim 1 or 2, characterized in that as active guide means (8) fans or injection nozzles for the air

(5) and/or as passive guidance means (8)

Flow resistances such as rods, sieves, perforated plates and / or baffles are arranged.

Plant according to one or more of the preceding claims, characterized in that at least one

Guide means (8) is arranged to be movable in the compensating air shaft (6) by means of an adjusting device (37), preferably for changing the position and/or the effective area (38).

System according to one or more of the preceding claims, characterized in that at least in parts of the compensating air shaft

(6) at least one partition (40) across the width (26) of the forming belt (25) and/or in the production direction (23) of the forming belt (10) to divide the cross section

(7) of Compensating air shaft (6) is arranged.

System according to one or more of the preceding claims, characterized in that the partition (40) is arranged to be movable by means of at least one adjusting device (41), preferably substantially transversely to the production direction (23).

System according to one or more of the preceding claims, characterized in that one or more partition walls (40) at least partially divide the compensating air shaft (6) into partial air shafts, with guide means essentially influencing the partial air shafts

(8), preferably arranged separately for each partial air shaft.

System according to one or more of the preceding claims, characterized in that at least parts of the compensating air shaft (6) with a larger cross section than the drop shaft (4) and / or that to change the cross section (7) of the compensating air shaft (6) and / or the At least one adjusting device (17, 29, 30, 37) is arranged in the chute (4).

9. Plant according to one or more of the preceding claims, characterized in that in which Compensating air shaft (6) at least one separating device (39) for grit (1) is arranged.

System according to one or more of the preceding claims, characterized in that the compensating air shaft (6) is arranged essentially parallel to the drop shaft (4).

Method for forming a grit mat from grit (1) on a forming belt (10) in the course of producing material panels by means of pressure and/or heat in a press, with a spreading device (3) above the forming belt (10) in the falling direction (11) and To supply the spreading device (3) with grit (1) in the direction of fall (11), a metering device (2) is arranged in front of the spreading device (3) and in between a chute (4) for the transport of the grit (1), characterized in that

that excess air (5) and/or air accelerated by the grit (1) from the chute (4) and/or the spreading device (3) is integrated or separately to the chute (4) by means of an opening (16, 31) on the input side Compensating air shaft (6) is accommodated, which is operatively connected to the drop shaft (4) essentially on the output side and/or to the scattering device (3), so that the output-side opening (15, 26, 32) of Compensating air shaft (6) transfers the air (5) to the metering device (2) and/or essentially to the drop shaft (4) on the input side and that in the compensating air shaft (6) the flow of air is controlled or regulated by means of guide means (8).

Basis weight profile across the width (36) and/or in

To influence or adjust production direction (23).