EP1908563A2 - Method, apparatus and installation to detect and remove defects from a material flow, in the production of boards - Google Patents

Abstract

A method for checking and removing non-uniformities during fabrication process in which a descending and/or sliding flow of material is checked for non-uniformities after pre-treatment from leakage or dispersion. The flow of material is initially spread by a fanning device, and then examined for non-uniformities by through-radiation and the ascertained non-uniformities are removed by a short-term extraction of a partial fraction over the width of the material flow, which is then re-processed. Independent claims are given for the following. (1) (A) A device for detecting and removing non-uniformities from a stream of material (2) (B) An installation for detecting and eliminating non-uniformities from moving flow of material during fabrication material boards and panels.

Description

The invention relates to a method for detecting and eliminating irregularities from a moving material flow in the course of the production of material plates according to the preamble of claim 1 and an apparatus for detecting and eliminating irregularities from a moving stream of material according to the preamble of claim 11. Further shows the Invention a system for detecting and eliminating irregularities from a moving material flow according to claim 21.

Production plants for material boards have, in principle, at least the following production phases: material comminution (wood cutting), material preparation (drying and gluing), material sorting and arrangement (classification and scattering) and finally pressing into a plate. In addition to the known methods and apparatus for this successive steps are further a variety of additional and supporting steps and devices necessary to ensure the highest possible process reliability in the production of material boards. At the same time, it must be ensured that tribological processes, wear and marginal phenomena or disruptions of the production process can not have any disruptive influences on the ongoing operation of a material plate production plant and at the same time safeguard the economic interests of the operator with regard to low investment costs and maintenance costs.

With regard to the required wishes from the industry, it is now necessary to ensure a high level of operational reliability in addition to the simplest possible, low-investment and low-maintenance construction of a manufacturing plant,

With DE 101 01 380 A1 is a device and route to the Sichterbeschickung known to be separated in the heavy parts and lumps from the flow of material before a scattering station. The device and line presented here is usually arranged between a dryer and a scattering station to fan out the material stream leaving the dryer and passing through a glue line and to feed it to an air classifier which filters out heavy parts and lumps from the material stream before the material stream in a spreading station a compressible spreading material mat is converted on a moving forming belt. For this purpose, a Sichterseschickungsstrecke for Sichtfer width up to 3.5 m is provided, the consists of at least one distribution fan, a belt feeder and an air classifier. In this case, a dividing fan for widening the Sichterbeschickungsstrecke is provided and formed from a vertically arranged tube in which longitudinal and in the conveying direction partitions are provided which divide the discontinued material flow in widening conveyor channels. To divide on several air classifier a distribution device is provided, which consists of a division rake and a baffle, which divides the material flow into two partial streams.

It has now been found that in the production of medium-density and high-density fibreboard (MDF and HDF boards) air classification with such a known system brings various disadvantages. On the one hand, the fiber temperature built up in the dryer is reduced from 60 ° to 45 ° C by using a classifier. On the other hand, a subsequent drying of the fibers occurs by 2-10% of the wood moisture, which must be checked by complex measuring methods and corrected again, since the wood moisture is an important catalyst for the setting of the glue used and the hardening of the material plate during and after the compression ,

Next is a disadvantage that high electricity costs incurred for the provision and heating of the moving transport air and additionally results in a high noise level, which in turn must be reduced by sound insulation measures. In addition, generally high investment costs for the Steel scaffolding is necessary and setting up a sifter needs a lot of enclosed space.

It is further known to those skilled in the art and related patent literature that a variety of methods and apparatus have existed for protecting a press from excessive density in a scattered press mat.

For continuous and discontinuous thin or high-density plate production, a precise check of the density of the pressed product mat must be carried out. Even the slightest density peaks, caused by over-compacted material, hardened glue lumps or metal splinters can cause costly damage to the stainless steel press belts of a continuously operating press or to the press plates of a cycle press.

Usually this is a scattered Pressgutmatte just before a press with suitable means (laser, radiation, altitude monitoring) checked and should be scattering errors or density increases, this is disposed of in a discharge bunker before the press. It is disadvantageous that sometimes several cubic meters of material must be disposed of, if Pressgutmattenhöhen of up to one meter and several meters wide use. If a very accurate density check of a pressed material mat already finished on a forming belt is carried out by means of radiation, this can lead to the fact that the Discharge bunker must be opened to sort out excess density and a consistent production is no longer possible.

The invention is based on the object of specifying a method by means of which the material streams fed from a dryer or a gluing station can be checked in a simple and effective manner in a simple and effective manner for irregularities, such as foreign bodies and / or glue lumps, and at the same time a simplified discharge of the Detected foreign body and / or Leimklumpen is possible. Next, a device is to be created, with which the method can be performed, but which is also suitable for itself to detect irregularities, such as glue lumps and / or foreign bodies in a flow of material and excrete. In addition, a system is shown, with which the material flow used can be reliably checked for irregularities in the production of material plates and a trouble-free use of the material flow during compression is possible.

The solution of the task for the method is that the material flow is spread by means of a fan chute, the material flow is then examined by irradiation for irregularities and then the detected irregularities are eliminated by briefly deriving a partial over the width portion of the material flow and Finally, the material flow of further processing is supplied.

The irregularities may be foreign bodies, glue lumps or similar other higher density material that has a higher density than the set control density for the production of material plates.

The solution to the problem for the device is that, for the uniform guidance of the material flow, one or more guide channels with parallel outer walls is arranged adjacent to a widening fan chute, a radiation device being arranged at the beginning of the guide channel and at a subsequent distance a discharge device.

The solution of the task for a system consists in the arrangement of the following system parts in series: a dryer and / or a cyclone, a rotary valve, a fan chute, a magnetic separator, a radiating device, a discharge device and other necessary equipment parts for the production of material plates.

• es wird ungenügendes oder sogar schädliches Material, in einem Materialstrom detektiert und sicher aussortiert,
• bei der Aussortierung wird ein Mindestmaß an Gebrauchsmaterial mit ausgeschieden, was die Effektivität des Verfahrens und der Vorrichtung erhöht,
• es ist eine sehr genaue Regeldichte des Materialstromes einstellbar, die kontinuierlich überwacht und eingestellt werden kann und
• es treten keine Temperatur- und/oder Feuchtigkeitsverluste des Materials (wie zum Beispiel bei einem Sichter) zwischen dem Trockner und dem Streugutbunker auf.

The advantages of the method according to the invention and such a device, which incidentally can also be operated alone and not only in connection with the method, are manifold.

• Insufficient or even harmful material is detected in a material flow and safely sorted out.
• during sorting, a minimum amount of utility material is excreted, which increases the effectiveness of the method and device,
• It is a very precise control density of the material flow adjustable, which can be continuously monitored and adjusted and
• there are no temperature and / or moisture losses of the material (such as in a sifter) between the dryer and the grit bin.

The method and the device according to the invention offer the possibility to check the material used before entering a grit hopper and the scattering to a pressed material mat and thus to prevent the segregation of large quantities of useful material by small precipitates of a part of the material flow.

In order to better understand this, it is necessary to take a closer look at the manufacture and treatment of the material. Usually chips and fibers are used in the production of wood-based panels, which are already delivered to a ready made from sawmills, on the other hand locally produced by crushing machines from delivered logs. It can happen every now and then that fragments of the saw blades from the sawmills or from the tools of the shredder arrive on site in the cycle and the material flow, which is pretreated in large dryers. there It is known that regularly rust breaks occur in the dryers and thus metallic particles and rust can get into the material flow here. In addition, therefore, after a drum dryer in the sense of the device according to the invention, a heavy material separator will be used which can excrete excessively large and heavy material from the material flow in advance. In this case, heavy parts are not transported by the air flow in a vertical pipe upwards due to gravity and can be separated out via a suitable discharge device, for example a rotary valve. As a rule, only a minimum amount of recyclable material is also eliminated, so that the installation of a heavy material separator generally only has a beneficial effect on the efficiency of the entire production plant. In the heavy material separator, excessively long pieces of wood are also rejected if defective chips are produced by means of a defective refiner. Also fibrous bark pieces of 30 - 200 mm in length and large and heavy rust fragments from the dryer can be eliminated here. Small pieces of iron which are not discharged via the heavy material separator are now eliminated in the device according to the invention by means of the magnetic separator arranged above the radiation device. It is advantageous that even here a broadening and thus dilution of the material flow has been made to a thickness of 10 cm to 20 cm. From the radiation device now the remaining particles are detected, or pieces of metal that are not through the heavy material separator or the magnetic separator have been eliminated, such as compacted pieces of wood, dust clumps with diameters of 5 to 50 mm and glue lumps.

Advantageously, the short-term dissipation of a width-wise fraction of the material flow is carried out with a separation flap which is introduced into the material flow, this being moved for example by a double-acting cylinder. In a further embodiment, the brief derivation of a partial width of the material flow over the width can be carried out by means of a blast of compressed air.

Further advantageous 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

Schematische Ansicht eines Anlagenaufbaus von einem Trockner bis zu einer kontinuierlich arbeitenden Presse,

Figur 2

eine Seitenansicht der Anlage von der Zellradschleuse bis zur Austragsvorrichtung Figur 1 und

Figur 3

eine zweite Ansicht der Anlage von der Zellradschleuse bis zur Austragsvorrichtung nach Figur 2.

Show it:

FIG. 1

Schematic view of a plant construction from a dryer to a continuous press,

FIG. 2

a side view of the system from the rotary valve to the discharge device Figure 1 and

FIG. 3

a second view of the plant from the rotary valve to the discharge device of Figure 2.

As shown in an overview of Figure 1 of an overall plant for the production of wood-based panels or the like and in the enlarged views of Figure 2 and 3, material, preferably chips, fibers or the like, is set in a dryer 8 in its moisture and a Wind tunnel 16 and optionally fed by a heavy material separator 9 with heavy-lift lock 26 a cyclone 7. The cyclone 7 can also be designed as a dryer cyclone. For pneumatic separation of the plant areas from the cyclone 7, a rotary valve 1 is provided, which emits the material flow more or less continuously in the Fächerschurre 2. In the fan chute 2, the incoming material flow is distributed in width and passed through the guide channels 5. The guide channels 5, which can be separated from each other by baffles 6, eventually lead past a magnetic separator 10, which removes magnetic iron parts from the flow of material. Subsequently, the material flow in the radiographic device 3 is irradiated by means of suitable radiation, preferably X-ray radiation, and examined for particles which have a higher density than the control density of the material flow. It is determined with a receiver 12, where and when the radiation emitted by the transmitter 11 radiation is attenuated too much by such foreign body. It can be seen that several transmitter 11 and receiver 12 can be arranged in series next to and even parallel to each other to achieve the most accurate measurement result possible. In this case, an overlapping radiation can also be provided.

Incidentally, the control density is the necessary density which has been set for the production of corresponding material plates. Such a radiation device is the subject of other patent literature and is not described in detail, because a person skilled in the operating principle of such a radiographic device 3 is obvious and he will select depending on the application. If a foreign body is detected in a region between in a region, preferably between two baffles 6 through the irradiation device 3, then in the discharge device in a predetermined time window, a separation flap 15 is moved into the flow of material. Depending on the design of the separation device 3, a portion of the material flow containing the determined foreign body is separated and diverted into the disposal area 14. Preferably, the separation flap 15 is moved by means of a double-acting cylinder 13 to ensure that only the smallest possible part of the material flow is deposited with the foreign body and the separation flap 15 is transferred as soon as possible back to the starting position. The constructive details such as sealing, material used, calculation of reaction time, and the like may be left to those skilled in the art.

The separation device 3 has, moreover, a disposal device 18 for the precipitated material of the material flow. Preferably, this may be designed as a screw conveyor 19.

In another embodiment, the separation flap 15 may be substituted by, for example, a pneumatic nozzle system or similar devices which, upon activation, cause a portion of the material stream to be transferred to the disposal area 14. Of course, a combination is conceivable, whereby it must be ensured that the elaborate discharge device is not hindered by flying material in their function. Incidentally, it is not always necessary to guide the flow of material in the radiographic device 3 and / or the discharge device 4 by means of baffles 6. It can also be arranged over the entire width continuous guide channel 5, which should be ensured that detected foreign matter on the route between radiographic device 3 and discharge device 4 can not migrate laterally and possibly slip past the activated Abscheideklappe 15 or equivalent. Depending on the material used in the material flow, it may be useful to arrange a sealing lip 17 in the guide channels 5 of the discharge device 4.

After the discharge device 4, the material flow is transferred to an accumulation belt 20 or another suitable conveying device and, if appropriate, fed to a dissolving device 21, for example consisting of opening rollers, before the material flow finally reaches a grit hopper 22. In the spreading material bunker 22, the material finally waits for further processing, this usually being scattered by a spreading head 23 onto a forming belt 24 and the pressing in a continuously operating one Press 25 includes. The necessary procedures and processes or the devices for this purpose are familiar to the expert and need not be further elaborated here. For the purposes of the application, the term foreign body encompasses particles which are particularly contained in the material flow and which have a different and / or higher density than the control density of the material stream. Further, it is conceivable that the discharge device has tubes or square pieces, through which the material flow is passed and which can be swung for a separation of a part of the material flow. In addition, it would be possible as a discharge device across the width sections of pneumatic nozzles (not shown) to be arranged, which press or transport the material flow in the disposal area. Due to the prevailing high temperatures of the material flow, it may be useful to avoid a condensation of water on the inner walls of the system parts from the rotary valve (1) to arrange a thermal insulation of the devices.

For example, the following dimensions and characteristics are used in a system that can be used:

The diameter of the wind tunnel 16 is about 1.5 m. The enlarged diameter of the heavy material separator is about 2 m. The effective final width of the Fächerschurre can vary from 2 to 6 m, the length may well be up to 6 m long. Depending on the embodiment and intended use, the Fächerschurre can also be made adjustable and variably change the respective fan widths. Preferably, in a material flow of 10 to 20 cm thickness, a segment (area between two baffles 6) in about 70 to 200 mm wide and is monitored by a portion of the radiating device 3, wherein a separating flap 15 or the like for this segment, the partial shares the material flow can be eliminated.

In such material streams wood particles have a density of 300kg / m3 in the control, whereas clumps of glue m ³ may have a density of up to 1,000 kg / cm and 1 to 6 in diameter.

List of Reference Numerals: DP1332EP

1.

rotary

Second

Fächerschurre

Third

Radiation device

4th

discharge

5th

guide channel

6th

baffles

7th

cyclone

8th.

dryer

9th

heavy particle

10th

Magnetic separator

11th

transmitter

12th

receiver

13th

Double-acting cylinder

14th

disposal area

15th

separating vane

16th

wind Tunnel

17th

sealing lip

18th

disposal device

19th

Auger

20th

anthology

21st

dissolver

22nd

grit bunker

23rd

spreading head

24th

forming belt

25th

continuously working press

26th

Schwergutschleuse

Claims (24)

A method for detecting and eliminating irregularities in the course of the production of material plates, wherein a falling and / or slipping material stream is checked for irregularities after a pretreatment before scattering on a forming belt, characterized by the following method steps: 1.1 the material flow is spread out by means of a fan chute, 1.2 the material flow is then examined by means of radiation for irregularities, 1.3 then the determined irregularities are excreted by brief derivation of a width over the width fraction of the material flow and 1.4 Finally, the material flow of further processing is supplied. A method according to claim 1, characterized in that between method step 1.1 and 1.2 from the planar Material flow smaller iron parts are separated with a magnetic field. A method according to claim 1, characterized in that prior to application of the method, the material flow passes through a heavy material separator. Method according to one or more of the preceding claims, characterized in that X-rays are used to irradiate the material flow. Method according to one or more of the preceding claims, characterized in that the material flow before and / or after a grit hopper is subjected to a loosening. Method according to one or more of the preceding claims, characterized in that the material flow is spread to a width of 1 to 8 m. Method according to one or more of the preceding claims, characterized in that the material flow only has a thickness of 10 after propagation in the region of the radiation up to 20 cm. Method according to one or more of the preceding claims, characterized in that for the brief derivation of a partial width of the material flow over the width of a compressed air blast is introduced into the material flow. Method according to one or more of the preceding claims, characterized in that a separating flap is introduced into the material flow for the brief derivation of a portion of the material flow which is partial over the width. Method according to one or more of the preceding claims, characterized in that the separating flap is moved by means of a double-acting cylinder. Device for detecting and eliminating irregularities from a falling and / or slipping material flow in the course of the production of material plates, wherein a fan chute is arranged for fanning the material flow,
characterized in that
for the uniform guidance of the flow of material following a widening fan chute (2) one or more guide channels (5) are arranged with parallel outer walls,
wherein at the beginning of the guide channel (5) a radiating device (3) is arranged and at a subsequent distance thereto a discharge device (4). Apparatus according to claim 11, characterized in that as discharge device (4) over the width of sections pneumatic nozzles are arranged. Apparatus according to claim 11, characterized in that as discharge device (4) over the width of the guide channel (5) sectionally Abscheideklappen (15) are arranged. Device according to one or more of the preceding claims 11 to 13, characterized in that the discharge device (4) is associated with a disposal area (14) with a discharge device (18). Device according to one or more of the preceding claims 11 to 14, characterized in that a magnetic separator (10) is arranged between the fan chute (2) and the guide channel (5). Device according to one or more of the preceding claims 11 to 15, characterized in that for the widthwise sectional guidance of the material flow baffles (6) for forming a plurality of guide channels (5) are arranged. Device according to one or more of the preceding claims 11 to 16, characterized in that the material flow is loosened by means of one or more opening rollers (21). Device according to one or more of the preceding claims 11 to 17, characterized in that for the removal of the separated material from the disposal area (14) a discharge device (18) is arranged. Device according to one or more of the preceding claims 11 to 18, characterized in that a screw conveyor (19) is arranged as the discharge device (18). Device according to one or more of the preceding claims 11 to 19, characterized in that from the rotary valve (1), a thermal insulation of the devices is arranged to a condensation of water on the Interior walls of the guide channels (5) to avoid. Plant for detecting and eliminating irregularities from a moving material flow in the course of the production of material plates, characterized in that arranged in a predetermined order: a) a dryer (8) and / or a cyclone (7), b) a rotary valve (1), c) a fan chute (2), d) a magnetic separator (10), e) a radiation device (2), f) a discharge device (4) and g) other necessary plant parts for the production of material plates. Plant according to claim 21, characterized in that after a dryer (8) a heavy material separator (9) is arranged. Installation according to claim 21, characterized in that on the heavy material separator (9) a heavy-lift lock (26) is arranged. Plant according to claim 21, characterized in that the further plant parts according to feature g) comprise a grit hopper 22, a spreading head (23) with forming belt (24) and a continuously operating press (25).

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