CN118528376A - Spreading method and spreader for bulk material - Google Patents

Abstract

The invention relates to a method and a device for spreading wood chips or wood fibers to form a bulk material mat during the manufacture of a material sheet, whereby spreading material is introduced into a spreading device by means of a metering unit, from which a first bulk material layer is spread onto a spreading belt conveyor. In order to increase the uniformity of the density distribution of the bulk material in the material mat, and to error in advance and, if necessary, by controlling the error, in a first step, a profile measurement is carried out in the transport direction after the first spreading device over the entire width of the first bulk material layer by means of radiation measurement or photometric measurement, and in the transport direction after the second spreading device over the entire width of the second bulk material layer by means of radiation and/or photometric measurement; the profile measurement value is transmitted to an evaluation and control device, with which the spread over the width of the first or second bulk material layer is at least partially adjusted by the first actuator, so that the profile measurement value is adapted to the nominal density profile.

Description

Spreading method and spreader for bulk material

Technical Field

The invention relates to a method for spreading bulk material, in particular wood chips or wood fibers, onto a spreading belt conveyor during the production of a material sheet to form a bulk material mat, a first bulk material is introduced from at least one first silo into a first spreading device arranged above the spreading belt conveyor by means of a metering unit, and a first bulk material layer is spread from the first spreading device onto the spreading belt conveyor, and a second bulk material, which is physically or chemically different from the first bulk material, is introduced from at least one second silo into a second spreading device arranged above the spreading belt conveyor by means of a metering unit, and a second bulk material layer is spread from at least the second spreading device onto the first bulk material layer on the spreading belt conveyor to form the bulk material mat.

The invention further relates to a spreader for spreading bulk material, in particular wood chips or wood fibers, onto a spreading belt conveyor during the production of a material sheet to form a bulk material mat, in particular for carrying out the method, wherein a first bulk material can be introduced from at least one first silo into at least one first spreading device arranged above the spreading belt conveyor by means of a metering unit and a first bulk material layer can be spread from the first spreading device onto the spreading belt conveyor to form the bulk material mat, and a second bulk material, which is physically or chemically different from the first bulk material, can be introduced from at least one second silo into at least one second spreading device arranged above the spreading belt conveyor by means of a metering unit and at least one second bulk material layer can be spread from the second spreading device onto the first bulk material layer on the spreading belt conveyor to form the bulk material mat.

Background

Many different spreaders for producing material sheets, in particular material sheets composed at least partly of wood chips or fibres, are known. These spreaders may have one or preferably a plurality of spreading devices from which a layer of bulk material (hereinafter "layer") is spread onto a spreading belt conveyor (typically a conveyor belt). The so-called bulk material mat produced is then pressed into a sheet of material by pressing and heating. By concatenating several spreading devices, a material sheet with several different material layers can be manufactured. Thus, the cover layer, for example a sheet of material, typically uses a different bulk material in terms of size or gel content or material than the bulk material of the intermediate layer.

A spreading device is understood here to mean a so-called spreading head (with or without alignment rollers for wood chips or fibers) and a wind-powered spreading device. Examples of such dispensing devices are described in DE 20 2016 102 898 U1 and DE 10 2015 112 013A1.

Whether only one layer is laid by a spreading device or a plurality of layers are laid from a plurality of layers one upon the other is irrelevant, the aim being to keep the height profile as uniform as possible over the width of the spread layers. This is important at the beginning of use in order to obtain a height profile that is so straight that the subsequent pressboard has as small a fluctuation in density as possible. However, even when turbulence occurs in the spreading and the glued bulk material adheres to the wall during the subsequent operation, this often results in a high degree of non-uniformity of the transverse profile which is only found at a later time.

It is known from EP4 082664 A1 to record the height profile of a spread bulk material mat by means of a displacement measuring device at the end of the spreading station and to influence the preceding spreading by means of an actuator if necessary in such a way that the height profile becomes uniform. For this purpose, a spreader head carriage of one or more spreader heads has been exemplified. However, in this method, each dispensed layer cannot be influenced in a targeted manner. Only the final result of the height profile can be corrected. The density distribution of the wood chip plate mentioned there cannot be predicted as the appearance of the contour of each layer is not detected.

A radiometric method, by means of which the density of a material sheet is determined directly, has already been described in DE 10 2005 020 297 A1. However, only the finished pressed sheet scanned with the radiation detector is referred to in this document. None of the bulk pads was tested, let alone the individual layers.

Disclosure of Invention

It is therefore an object of the invention to improve the uniformity of the bulk density distribution in a bulk material pad and to find errors in advance and to exclude them, if necessary, by control.

The term "material sheet" refers in particular to a wood chip sheet made of wood chips. In principle, however, the invention also includes fiber boards made from wood fibers or annual plants and also partly from man-made products. The bulk material mat spread onto the spreading belt conveyor is pressed into wood material boards using pressure and heat, for example in a press, for example a continuously operating press or a circulating press. The quality of the wood material board produced here depends mainly on the quality or the properties of the bulk material mat produced by means of the spreading station comprising a plurality of spreading devices. The bulk material is typically a rubberized bulk material, such as rubberized wood chips or fibers, which are supplied from a bulk bin or a metering bin to a spreading device.

The spreading station should have a plurality of spreading devices or spreading heads, in particular in the case of a multi-layered bulk material mat which should be produced from two cover layers (for example from a fine material) and one or more intermediate layers (for example from a coarse material). The individual layers are thus composed of different spreading materials, wherein the difference can be not only in the size of the bulk material, but also in the material or the amount of glue added, for example. The individual spreading devices are then arranged one after the other in the conveying direction above the spreading belt conveyor, so that the first cover layer is first spread onto the spreading belt conveyor, the intermediate layer is then spread onto the first cover layer, and the second cover layer is then spread onto the intermediate layer. The spreader of the invention is particularly advantageous for producing a layer with a good spreading profile in width, i.e. a layer with a spreading profile which can be extruded to a density profile which is uniform in width.

The object relating to the method is thus achieved by the features of claim 1 and in particular by the fact that in a first step

Profile measurement is carried out in the transport direction after the first spreading device over the entire width of the first bulk material layer by means of radiometric or photometric measurement,

-Profile measurement is performed in the transport direction after the second spreading device over the entire width of the second bulk layer by radiation and/or photometric measurement;

-transmitting the acquired profile measurement values to an analysis evaluation and control device, and

Using these acquired profile measurement values, the spreading quantity over the width of the first or second bulk material layer is adjusted at least in part by at least one first actuator, so that the profile measurement values are adapted to the nominal density profile.

The term "contour measurement" is understood hereinafter as meaning the measurement of the height contour (preferably by photometric measurement) or the measurement of the density contour (preferably by radiometric measurement) on the bulk material layer. Thus, for example, a measurement is already made after the spreading of the first layer of the bulk material mat, which measurement provides how the density distribution of the first layer of the bulk material mat is formed separately, and this measurement is compared with the measurement after the spreading of the second layer. The first layer is typically a cover layer that is thinner than the intermediate layer. However, even in the case of such a cover layer, density distribution errors are substantially excluded. And thus does not result in error accumulation with the second layer. If the profile measurement of the first material layer yields an insufficient uniformity over the width of the bulk material mat, the nominal density profile can be corrected in the first material layer by means of the first actuator, which is actuated by the evaluation and control device such that the profile becomes uniform. The description of the dependent claims further describes possible actuators.

In this case, if the contour errors do not add up to the contour of the second material layer, but also in the case of the second material layer, it is ensured that, in the second step, contour measurements are also carried out in the conveying direction after the second spreading device over the entire width of the second bulk material layer by radiation and/or photometric measurements; the acquired profile measurement values are transmitted to the control device and, using these, the spread over the width of the second bulk material layer is at least partially adjusted by means of at least one second actuator in such a way that the profile measurement values are adapted to the nominal density profile.

Thus, the spreading of the second material layer can also be influenced with the second control circuit such that the height profile is constant and the thickness of the subsequent material sheet is better predicted taking into account the different spreading amounts and spreading weights.

Advantageously, it is provided that the contour measurement is also performed in the case of other, however at least three, dispensing devices. In the most advantageous case, there is one profile measuring device even after all spreading devices. The probability that the actuators which can be assigned to the individual dispensing devices can be influenced in the direction of the desired height profile or density profile is thus greatly increased again.

If photometric measurement methods are selected, electron-optical distance measurement can be used here. Here, laser light or infrared light may be used. The corresponding laser sensor or infrared sensor must receive the reflected light rays. The method by laser triangulation is particularly suitable.

This approach is independent of high radiation coverage (e.g., alternative radiometric measurements). At the same time, the measuring speed still makes high resolution possible. Topographical measurements of the width can be made in each bulk layer to determine the thickness profile or profile of the density to be predicted.

Alternatively, however, radiometric measurements by gamma rays or ethical rays may also be suitable, since the density profile can then be determined directly at the cost of safety.

Preferably, the first measuring profile acquired after the first dispensing device and the second measuring profile acquired after the second dispensing device are transmitted to a control device, which compares the first measuring profile with the first nominal profile and exerts an influence on at least one actuator of the first dispensing device, so that deviations of the first measuring profile are at least partially compensated for when the second measuring profile is observed.

Alternatively, the first measured profile acquired after the first dispensing device and the second measured profile acquired after the second dispensing device are preferably transmitted to a control device, which compares the first measured profile with the first nominal profile and exerts an influence on at least one actuator of the second dispensing device, so that deviations of the first measured profile are at least partially compensated for when the second measured profile is observed.

Since at least two measurement profile acquisitions are used, there are two effective processing methods by comparing the first and second measurement profiles, adjusting the actuators in the first or second dispensing device such that an optimized second measurement profile is obtained. If the deviation in width in the second measuring contour is large, the actuator can of course also be adjusted in both dispensing devices.

This method can be extended to any number of dispensing devices with better results if profile measurements are made after each dispensing device.

It should be noted here that the profile measurement varies by a maximum of ±5% in width at least in the one first bulk layer. This was found by profile measurement after dispensing the device. Only if the deviation is large should feedback be applied to the actuator of the first dispensing device. If the deviation is small, the control device should be used in such a way that it compensates the profile by adjusting the actuators of the second and optionally further spreading devices.

In a particularly preferred manner, it is provided that a bulk material mat consisting of an upper and a lower cover layer and at least one intermediate layer is spread with at least three spreading devices.

The cover layer can thus be spread with a different bulk material than that used in the intermediate layer or intermediate layer. In many cases, for example, the cover layer is spread with a finer material in order to facilitate the coating, or particularly long wood chips are used in order to achieve a greater flexural strength of the subsequent material sheet.

It is therefore preferred that only the changed height of the at least one intermediate layer is dispensed when manufacturing a new material sheet thickness.

The setpoint value of the profile measurement of the cover layer is thus unchanged and can be maintained in the control system. The profile measurement of the intermediate layer whose thickness has now been changed can be easily integrated into the control system with new values.

In particular, if the profile measured after the last spreading device is sufficiently straight, a continuous extrusion of the bulk material mat blank can be achieved in an efficient manner in a continuous belt press.

Thus, in one continuous process flow, a sheet of material having a uniform density across the width and length can be produced, which can be sawn into rectangular panels of the desired dimensions. By means of this uniform density profile, which is produced by a plurality of measuring profiles, the subsequent grinding step is essentially dispensed with.

By performing a height profile measurement after each spreading of the material layer by the spreading device, such a density profile or density distribution over the length and width of the finished material sheet can be predicted in a much more reliable manner than hitherto, which gives the invention a significant added value.

The object of the invention is achieved in relation to a spreader for spreading bulk material, in particular according to the method claims, by the features of claim 14 and in particular by providing a profile measuring device which uses radiation or photometric measuring methods over the entire width in the conveying direction after the first spreading device and after the second spreading device, which allows radiation irradiation over the entire width to be achieved, and at least one sensor which is able to continuously detect light rays, ron rays or gamma rays being arranged above and/or below the bulk material mat.

The inventors have found that by spreading the profile measuring device on the belt conveyor for obtaining the height profile or the density profile not only after the first spreading device but also after the second spreading device, a much higher accuracy of the density distribution of the material sheet can be achieved.

As mentioned above, radiometric or photometric measurements, in particular laser triangulation, are suitable methods for obtaining profile measurements. In laser triangulation, it is preferably provided that the light beam in the form of a laser beam impinges on the bulk material layer at an angle of between 20 ° and 70 ° to the surface of the bulk material layer, is reflected there and is received by a suitable light sensor which registers the distance very precisely, so that a height measurement profile over the width of the bulk material layer can be produced.

Preferably, the spreader has more than two spreading devices for producing a plurality of layers, and a contour measuring device is provided after the more than two spreading devices.

It is advantageously ensured that an evaluation unit and a control device are provided, by means of which the height profile over the width of the bulk material layer can be acquired from the profile measurement and an adaptation command can be transmitted to at least one actuator of the first or second or further spreading device.

Thus, a wide variety of possible ways of modifying the height profile obtained, that is to say, obtaining as uniform a density distribution as possible in the manufactured material sheet after the pressing process, are produced.

The dispensing device may have different actuators. Three basic actuators are designed in the present application, however the present application does not exclude further alternatives. Advantageously, the actuator is a) a width-wise dispensing device during the filling of the silo, b) a width-wise dispensing device in the spreading device and/or c) a material removal device acting on the bulk material layer.

All of these actuators allow for varying and adjusting the spread over the width of the bulk material pad. It is thus possible to provide more bulk material to thinner areas of the bulk material pad and less bulk material to thicker areas of the bulk material pad.

In a particularly preferred variant of the actuator in the dispensing device, the dispensing means is a zone-controlled discharge device. In this case, a greater or lesser part of the bulk material in width can be deflected out of the spreading device in regions, for example by means of a plurality of flaps, in the spreading device and discharged for reuse. In this way, the overspray area of the bulk material pad is provided less with new bulk material, which is advantageous for uniformity in width.

It is particularly advantageous if a visualization device for the profile measurement and/or the predicted density distribution is present.

The operator of the device can always check the thickness profile or the density profile of the material sheet. Depending on the degree of automation of the dispensing control, an operator may intervene in an emergency and manually adjust the actuator. This possible approach can be used in particular in the case of bulk material adhering to the wall of the spreading device.

Drawings

The invention is explained in detail below with reference to the drawings, which show only embodiments. The drawings show:

FIG. 1 is a side view of an illustrative spreader;

FIG. 2 is an exemplary dispensing apparatus;

FIGS. 3a and 3b are longitudinal and cross-sections of a discharge device (second embodiment of an actuator) within a dispensing device;

FIG. 4 is a cross section of a removal device (third embodiment of an actuator) on a spreader belt conveyor;

FIG. 5 is an enlarged view of a portion of FIG. 1, including a dispensing device (first embodiment of an actuator) in width during bin filling;

Fig. 6 is a schematic contour measurement device.

Detailed Description

FIG. 1 shows a schematic side view of a spreader. Below the not shown bulk material supply system there are a number of different silos 3a, 3b, 3c, 3d, which can receive and store bulk materials 4a, 4b, 4c, 4d. The different small letters following the reference numerals are intended to indicate that the bulk material 4 in all bins 3 may be different. For example wood chips of different lengths may be stored in a bin or plant fibres or plastics may be stored in one bin, for example. The bulk material 4a, 4b, 4c, 4d is introduced into the spreading device 2a, 2b, 2c, 2d via a metering unit 13. The small letters lying behind represent different possibilities here and in the further course of the bulk material layer 6. The invention is of course not limited to four bins and spreading devices in this embodiment. However, in order to implement the present invention, at least two dispensing devices must be present.

From there, one or more layers of spreading are carried out as required, wherein different special requirements are possible between the intermediate layer and the cover layer. In this embodiment, it is considered that wind spreading is used from spreading devices 2a and 2d for the cover layer, while what is considered is used from spreading devices 2b and 2c for the two intermediate layers is what is called indirect spreading via a spreading roller system. In the case of indirect spreading, the bulk material discharged from the bulk material bin falls onto a so-called spreading roller 19, which can dispense the bulk material and, if necessary, also orient it (see also fig. 2 for this). The spreading of the layers by the spreading device in many cases has a decisive different influence on the strength and usability of the finished material sheet, depending on whether the wood chips or fibers are irregular along or transversely to the direction of travel of the bulk material mat 7 or are brittle.

The bulk material layers 6a, 6b, 6c, 6 d-in fig. 1, which are only marked 6-are laid one above the other on the spreading belt conveyor 5 after spreading by one spreading device 2a, 2b, 2c, 2d, respectively, since the individual layers are not distinguishable. Here, the bulk layers 6a and 6d may be, for example, cover layers of subsequent material sheets, while the bulk layers 6b and 6c may be intermediate layers.

In the exemplary shown spreader 1, one profile measuring device 8 is arranged next to each spreading device near the spreading belt conveyor 5. Such a profile measuring device can measure the height profile of the bulk material layer 6 or of the entire bulk material pad 7, for example, in the photometric measuring range of laser triangulation. Or using a radiometric method that can directly provide information on the density distribution in the bulk material pad. In both variants, measurements are made over the entire width of the bulk material mat 7, respectively, for which purpose corresponding sensors 16 for the conversion result are provided. The measurement results are transmitted to an electronic analysis and evaluation unit and control device 9, which can influence an actuator 10 for correcting the measured profile (see fig. 3 to 6 for details).

The analytical evaluation is based on at least two measurement profiles. The first and second measurements are compared and used to operate the existing actuator 10 in such a way that at least the second measurement profile has a uniform height distribution. The density profile of the finished material sheet can be predicted with the aid of the known bulk material in the respective spreading device 2a, 2b, 2c, 2d together with the first measured profile of the bulk material layer 6, 6a, 6b, 6c, 6 d.

In addition, different correction approaches can also be used in this configuration with at least two bulk material layers and two associated profile-measuring devices 8, 8.1, 8.2. An alternative is to adjust the first measuring profile by means of an actuator 10 in and around the first spreading device. In this case, the variation in the profile over the width is preferably a maximum variation of ±5%. Another or additional alternative is to measure the at least two profiles and then equalize the first measured profile by a spreading actuator around the second spreading device.

The evaluation unit and control device 9 can thus display the actual contour values, for example from a height measurement or a density measurement over the width. However, the evaluation unit and the control device can also display the possible density profiles of the finished material sheet using a suitable correlation matrix provided by empirical or calculated values to the evaluation unit and the control device. The contours are provided to the operator in the form of current values, suitably on a visualization means 17, for example a display screen or an operator mobile phone display screen (see also fig. 6).

If a contour measuring device is provided after each bulk material layer 6a, 6b, 6c, 6d and contour measuring values are used for the actuator 10, which again corrects these or other contour measuring values in the control loop, the invention allows the correction to be more and more precise as the number of bulk material layers 6 increases.

The actuator basically comprises three alternative or common devices.

As a first exemplary device, an actuator 10 can be provided which fills the bins 3, 3a, 3b, 3c, 3d for bulk material in such a way that more bulk material is discharged across the width to the spreading devices which deposit too little material on the spreading belt conveyor. For this purpose, a distributor device 12, for example a discharge chute 18 pivotable over the width of the silo, can be used as an actuator 10 in or upstream of the silo. This discharge chute is schematically shown in fig. 5. The bin is then filled higher at certain locations and more bulk material can be discharged to the indirect dispensing means 2b, 2c at these locations also due to the higher material pressure.

Fig. 2 schematically shows an exemplary dispensing device 2, 2b, 2c. It contains a plurality of different spreading rollers 19 which are usually sized to distribute and separate the bulk material and, if necessary, also to align the bulk material, i.e. the chips or fibers, in their spreading position before they fall onto the bulk material pad 7. The direction of the amount and the direction of movement of the bulk material 4 is shown in fig. 2 by the bold black arrow, as it is dispersed from the silo 3 into the spreading device. The white arrow with a black outline symbolically represents only an exemplary direction of rotation of the spreader roll 19. In this sorting process, as a second possible actuator, there may be a plurality of adjustable discharge devices 11 arranged across the width. These discharge devices reject a settable portion of the bulk material 4 in one or more selected width regions, so that it does not fall down onto the bulk material pad, but is moved laterally. In the embodiment according to fig. 2, however, which is shown more clearly in fig. 3a and 3b, the discharge device is a plurality of flaps 23 side by side which, depending on their degree of turning, can receive a quantity of bulk material. The received material is then directed to an auger 24 and removed laterally. It can then be reintroduced back into the silo. The flap 23 is adjusted and pivoted by means of a small servomotor which can be operated electrically or pneumatically. They are regulated by the evaluation unit and the control device on the basis of the acquired measurement profile, so that a control circuit is formed for a bulk material mat which is as homogeneous and of uniform height as possible and which, after extrusion, forms a material sheet with very little density deviation. This discharge device is a second exemplary version of the actuator 10.

As a third exemplary embodiment of the use of an actuator 10, reference is made to the applicant's prior document DE 3938681 A1. Fig. 2 described therein is used again as fig. 4. Based on the results from the at least two measurement recordings, the motor-driven tappet 21 is pressed with a pressure that differs in width against the conveyor belt 20 of the spreader belt 5, so that the sections with a high density are pressed more strongly against the cylindrical levelling roller and the sections with a lower density are pressed more weakly against the cylindrical levelling roller. The leveling roller removes the bulk material at the elevation, thereby creating a new distribution of bulk material, with the aim of achieving a more uniform result in width in the second profile measuring device.

In an alternative embodiment, not shown here, the levelling roller may also be segmented, the individual segments being arranged at different heights around the roller axis. The conveyor belt may then be extended on a flat, horizontal basis. However, this conceals the disadvantage that the rollers cause a complex construction with eccentric adjustment for each roller segment.

Fig. 5 also shows the positions of the two contour measuring devices 8.1, 8.2 in connection with the invention. In this embodiment, height profile measurement using photometric methods (laser triangulation devices) is desirable and is shown in fig. 6. In this case, the laser radiation is directed from the laser emitter 15 onto the uppermost layer 6a, 6b of the spread material, for example at an angle of 20 ° to 70 °, and is detected by the image sensor 16. With this method, the height profile of the bed can be precisely determined. The arrow indicates the direction of travel of the bulk material pad. After the spreading of the lower cover layer 6a, the height profile is determined by means of the first profile measuring device 8.1. For this purpose, the laser emitter 15 emits at least one laser beam over the entire width of the bulk material layer 6a, which is shown in broken lines. The image sensor 16 can easily measure the height profile. The same procedure is performed on the dispensed second layer 6b with the contour measuring device 8.2. The increasing height of the second layer 6b during spreading is omitted from the figures, only the final height after the second spreading device is shown.

The two height profile measurements can be transmitted to an evaluation unit and control device 9, which performs a corresponding conversion and prediction of the density of the finished material sheet and is provided to the device operator on a visualization means 17, for example a display screen. The limit value can thus also be displayed visually on the display screen in the manner described.

However, the invention may equally well be applied to radiometric methods. Such measuring devices associated with the production of material sheets are known, for example, from EP 4 082664 A1 and DE 10 2005 020 297 A1, as already described at the outset.

List of reference numerals

1	Spreader
		2、2a、2b、2c、2d	Dispensing apparatus
3、3a、3b、3c、3d	Bulk material bin
		4、4a、4b、4c、4d	Bulk material
5	Spreading belt conveyor
		6、6a、6b、6c、6d	Bulk material layer
7	Bulk material pad
		8、8.1、8.2	Contour measuring device
9	Analysis evaluation unit and control device
		10	Actuating mechanism
11	Discharge device in a spreading device
		12	Distributing device of stock bin
13	Metering unit
		14	Removal device
15	Laser transmitter
		16	Sensor for detecting a position of a body
17	Visualization device
		18	Pivotable discharge chute
19	Cloth spreading roller
		20	Conveying belt
21	Motor-driven tappet
		22	Leveling roller
23	Turning plate
		24	Screw conveyor
25	Servo motor

Claims (22)

1. Method for spreading bulk material (4, 4a,4b,4c,4 d), in particular wood chips or wood fibers, onto a spreading belt conveyor (5) during the manufacture of a material sheet to form a bulk material mat (7),

Introducing the first bulk material (4, 4a,4b,4c,4 d) from at least one first silo (3, 3a,3b,3c,3 d) into a first spreading device (2, 2a,2b,2c,2 d) arranged above the spreading belt conveyor (5) by means of a metering unit (13), and

Spreading a first layer of bulk material (6, 6a,6b,6c,6 d) from a first spreading device (2, 2a,2b,2c,2 d) onto a spreading belt conveyor (5), and

Introducing a second bulk material (4, 4a,4b,4c,4 d) which is physically or chemically different from the first bulk material from at least one second silo (3, 3a,3b,3c,3 d) into a second dispensing device (2, 2a,2b,2c,2 d) arranged above the dispensing belt conveyor (5) by means of a metering unit (13), and dispensing a second bulk material layer (6, 6a,6b,6c,6 d) from at least the second dispensing device (2, 2a,2b,2c,2 d) onto the first bulk material layer (6, 6a,6b,6c,6 d) on the dispensing belt conveyor (5) to form a bulk material mat (7),

It is characterized in that the method comprises the steps of,

In the first step

-Profile measurement by radiation or photometric measurement over the entire width of the first bulk material layer (6, 6a,6b,6c,6 d) after the first spreading device (2, 2a,2b,2c,2 d) in the transport direction, and

-Profile measurement is performed over the entire width of the second bulk material layer (6, 6a,6b,6c,6 d) by radiation and/or photometric measurement after the second spreading device (2, 2a,2b,2c,2 d) in the conveying direction;

-transmitting the acquired profile measurement values to an analysis evaluation and control device (9), and

-Using these acquired profile measurements, adjusting the spreading quantity over the width of the first or second bulk material layer (6, 6a,6b,6c,6 d) at least partially using at least one first actuator (10) such that the profile measurements are adapted to the nominal density profile.

2. Method according to claim 1, characterized in that in the second step the spreading over the width of the second bulk layer is also adjusted at least partly with at least one second actuator (10) such that the profile measurement is adapted to the nominal density profile.

3. A method according to claim 1 or 2, characterized in that the spreading is performed by means of a further, however at least three spreading devices (2, 2a,2b,2c,2 d), and that the radiation or photometric profile measurement is performed in the conveying direction also over the entire width afterwards.

4. A method according to any one of claims 1 to 3, characterized in that photometric profile measurement is performed by means of electron optical distance measurement.

5. The method of claim 4, wherein the electro-optical distance measurement is performed by laser triangulation.

6. The method according to any one of claims 1 to 5, characterized in that the radiometric measurement is performed by gamma rays or ethical rays.

7. A method according to any one of claims 1 to 6, characterized in that a first measurement profile acquired after the first dispensing device (2, 2a,2b,2c,2 d) and a second measurement profile acquired after the second dispensing device (2, 2a,2b,2c,2 d) are transmitted to the control means, and the analytical evaluation unit and the control means (9) compare the first measurement profile with the first nominal profile and exert an influence on at least one actuator of the first dispensing device such that a deviation of the first measurement profile is at least partially compensated when the second measurement profile is observed.

8. Method according to any of claims 1 to 6, characterized in that a first measured profile acquired after a first dispensing device and a second measured profile acquired after a second dispensing device are transmitted to a control device, and the control device compares the first measured profile with a first nominal profile and exerts an influence on at least one actuator of the second dispensing device such that deviations of the first measured profile are at least partially compensated for when the second measured profile is observed.

9. The method according to any one of claims 1 to 8, characterized in that the profile measurement is adapted such that it varies by a maximum of ±5% in width at least in the one first bulk layer.

10. The method according to any one of claims 1 to 9, characterized in that a bulk material mat (7) consisting of one upper and one lower cover layer and at least one intermediate layer is spread with at least three spreading devices (2, 2a,2b,2c,2 d).

11. The method according to claim 10, wherein the height of at least the at least one intermediate layer is spread differently in different finished products during the manufacturing of the material sheet.

12. Method according to any one of claims 1 to 11, characterized in that the bulk material mat (7) is extruded in a continuous belt press into a finished material sheet.

13. A method according to any one of claims 1 to 12, characterized in that the density distribution in the finished material sheet is predicted from the acquired profile measurement values.

14. Spreader for spreading bulk material, in particular wood chips or wood fibers, onto a spreading belt conveyor (5) during the manufacture of a material sheet to form a bulk material mat (7), in particular for carrying out the method according to claims 1 to 13,

The first bulk material (4, 4a,4b,4c,4 d) can be introduced from at least one first silo (3, 3a,3b,3c,3 d) into at least one first dispensing device (2, 2a,2b,2c,2 d) arranged above the dispensing belt conveyor (5) by means of a metering unit (13), and

The first bulk material layer (6, 6a,6b,6c,6 d) can be spread from the first spreading device onto a spreading belt conveyor to form a bulk material mat, and

The second bulk material (4, 4a,4b,4c,4 d) which is physically or chemically different from the first bulk material can be introduced from at least one second silo (3, 3a,3b,3c,3 d) into at least one second dispensing device (2, 2a,2b,2c,2 d) which is arranged above the dispensing belt conveyor (5), and

At least one second bulk material layer (6, 6a,6b,6c,6 d) can be spread from a second spreading device (2, 2a,2b,2c,2 d) onto the first bulk material layer (6, 6a,6b,6c,6 d) on the spreading belt conveyor (5) to form a bulk material mat (7),

It is characterized in that the method comprises the steps of,

A profile measuring device (8,8.1,8.2) using radiation or photometric measuring methods over the entire width is arranged downstream of the first dispensing device (2, 2a,2b,2c,2 d) and downstream of the second dispensing device (2, 2a,2b,2c,2 d) in the conveying direction, which allows radiation irradiation over the entire width and at least one sensor (16) is arranged above and/or below the bulk material mat (7) in order to be able to continuously detect light rays, ron rays or gamma rays.

15. Spreader according to claim 14, characterized in that the light rays in the form of laser rays impinge on the bulk material layer (6, 6a,6b,6c,6 d) at an angle of between 20 ° and 70 ° to the surface of the bulk material layer.

16. The spreader of any one of claims 14 to 15, characterized in that the spreader has more than two spreading devices (2, 2a,2b,2c,2 d) and that contour measuring means (8,8.1,8.2) are provided after a plurality of spreading devices (2, 2a,2b,2c,2 d), respectively.

17. Spreader according to any one of claims 14 to 16, characterized in that an analytical evaluation unit and a control device (9) are provided, by means of which the height profile over the width of the bulk material layer can be acquired from the profile measurement and the adaptation instructions can be transmitted to at least one actuator (10) of the first or second or further spreading device (2, 2a,2b,2c,2 d).

18. Spreader according to claim 17, characterized in that the actuator (10) is a dispensing device (12) in width during the filling of the silo.

19. The spreader of claim 17, wherein the actuator is a width-wise dispensing device in the spreading apparatus.

20. A spreader as claimed in claim 19, characterized in that the dispensing means is a zone-controlled discharge device (11).

21. A spreader as claimed in claim 17, characterized in that the actuator (10) is a material removal device (14) acting on the bulk material layer (6, 6a,6b,6c,6 d).

22. Spreader according to any one of claims 14 to 20, characterized in that there are visualization means (17) for contour measurement and/or predicted density distribution.