EP3294513A1

EP3294513A1 - Device for continuous heating of material

Info

Publication number: EP3294513A1
Application number: EP16723711.4A
Authority: EP
Inventors: Helmut Bauser
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2015-05-11
Filing date: 2016-05-11
Publication date: 2018-03-21
Also published as: CN107580540A; CN107580540B; DE102015107380A1; DE102015107380B4; US20180162010A1; WO2016180889A1

Abstract

The invention relates to a device for the continuous heating of materials made from substantially non-metallic material, comprising a continuous furnace (1) for the continuous heating of material (3) on an continuously circulating transport belt (10), wherein the continuous furnace (1) has a plurality of magnetrons (4) for generating electromagnetic waves and wave guides (5) with outlet openings (6) for supplying the waves into a radiation space (14), and wherein the outlet openings (6) of the wave guides (5) have a main axis. The invention is characterized in that for at least two outlet openings (6) which are arranged in closest proximity in and/or transverse to the production direction (15), the main axes (23) of the outlet openings (6) define an angle greater than 0º and/or the connecting line (25) of the focal points (24) of the surfaces of the outlet openings (6) define an angle greater than 0º to the perpendicular to the production direction (15).

Description

DEVICE FOR THE CONTINUOUS AWARENESS OF MATERIALS

The invention relates to a device for continuously heating materials of substantially non-metallic material, according to the preamble of claim 1.
The continuous heating of material, in particular of substantially non-metallic material, plays a crucial role in many areas of the production of products and intermediates.
In particular, in the compression of crushed or digested biomass, wood or wood-like materials to material plates, the continuous heating of the material is of crucial importance. Examples of such material panels are MDF panels of medium density fibers, oriented chipboard (OSB), veneer panels (LVL, OSL), fiber insulation panels / mats or the like. To increase the production capacity of continuously operating presses, it is also known to heat the material scattered to a web or strand with suitable devices prior to entry into the press. Due to the higher heat at the beginning of the compression, the press requires less time to heat the fleece. Accordingly, the press can be made shorter or operated faster. Hot air or steam preheating or the use of high-frequency radiation (HF, MW) for preheating in microwave continuous furnaces, referred to below as the continuous flow furnace, have proven successful. The physical principle is based on the conversion of electromagnetic energy into heat energy in the absorption of microwaves by the material to be heated.
A method and a device for heating a nonwoven in front of a press is known from EP 2 247 418 B1. In this disclosure, it is proposed that 20 to 300 microwave generators with a magnetron power of 3 to 50 kW and a frequency range of 2400 - 2500 MHz are to be arranged in a continuous furnace per press surface side. The large number of generators and the frequency used, which are necessary for the device and the method advantageously result in a small size of the radiation openings in the boiler room at the microwave frequency used. The disclosure teaches the skilled person only that a plurality of microwave generators are used with the same power and should be controlled accordingly evenly.
The apparatus and method described in this patent have been proven in industrial use, but can be further improved for industrial application.
It is also generally known to homogenize the microwaves within a heating chamber, hereinafter called radiation space, by means of suitable devices. Such devices are for example metallic rotary blades. Alternatively, the material to be heated can stand on rotating turntables. Even in a continuous furnace charged with several microwave generators, hereafter called magnetrons, such a homogenization of the radiation within the radiation space may be useful, even if already the material to be heated is continuously guided by a conveyor belt through the radiation space.
Details regarding safety-relevant embodiments or other embodiments of the lock technology of the continuous furnace for introducing and discharging the material are described in further prior art and are not the subject of the present invention.
In the above-mentioned prior art, a plurality of magnetrons are used to produce the necessary heating of the material. The effort seems justified, since the material can be warmed through without introducing moisture into the material, as would be the case for example with the use of steam. The higher energy input and the associated costs pay off due to the lower specific energy consumption per unit of the end product.
A disadvantage of the above-mentioned prior art is that despite the above-mentioned possibilities to even out the radiation in the radiation space, z. Wobble, moving material, the result of heating is too irregular. Emerging heat or under heated areas cause problems in the curing of the material in the press. In particular, in the production of material plates such inhomogeneities in the temperature profile lead to reduced transverse tensile strength of the material plate and thus to rejects or inferior material.
The object of the present invention is to develop the device and the method so that the uniform heating of the material is ensured.
The invention relates to a device for continuously heating materials of substantially non-metallic material, comprising a continuous furnace for the continuous heating of material on an endlessly circulating conveyor belt, wherein the continuous furnace a plurality of magnetrons for generating electromagnetic waves and waveguides with outlet openings for feeding the waves in a radiation space, and wherein the outlet openings of the waveguides have a major axis.
According to the invention, the stated object of the device is achieved in that at least two outlet openings, which are arranged in and / or transverse to the production direction as next neighbor, the main axes of the outlet openings form an angle greater than 0 ° and / or the line connecting the centers of gravity of the surfaces the outlet openings forms an angle greater than 0 ° to the perpendicular to the production direction.
In the following, the main axis is understood to mean the longest axis of the outlet openings of the waveguides, unless otherwise defined. In the case of rectangular outlet openings, the main axis is understood to mean the longer perpendicular bisector, the perpendicular bisector in the case of square outlet openings, the longest diameter for oval outlet openings, and the diameter for round outlet openings. For the arrangement as nearest neighbor, the distance between the centers of gravity of the surfaces of the outlet openings in and across the production direction is considered for this purpose alone. From the smallest distance of the focal points across the production direction, the next neighbor results across the production direction, from the smallest distance in the production direction results in the nearest neighbor in the direction of production.
The invention has recognized that the arrangement of the outlet openings of the waveguide in radiant space is of particular importance. The present invention thus has the advantage that by selectively rotating the main axes of outlet openings, and / or rotating the line connecting the centers of gravity of the surfaces of the outlet openings relative to the vertical to the production direction of at least two outlet openings, which as the nearest neighbor in and / or across are arranged to the production direction, the heat input into the material can be influenced to a particular extent and in particular leads to a homogenization of the heat input. The temperature distribution in the material thus becomes more homogeneous, which ultimately also affects the properties of the material. Hitzeester, thus area in which an increased energy input takes place during the transport of the material in the continuous furnace, can be prevented in an advantageous manner. The material is thoroughly heated, which also has a beneficial effect on subsequent processes. The number of outlet openings or the magnetrons is ultimately dependent on the material to be heated. However, the arrangement of the outlet openings according to the present invention also enables a targeted incorporation of heat tailored to the material. By such a staggered arrangement of the outlet openings according to the present invention, the vectors of the microwave radiation now enter at different angles in the material, which can lead to different levels of excitation in the material itself. It is also advantageous that areas which were not previously detected by microwave radiation or which were heated only indirectly by means of microwave radiation can now also be exposed to microwave radiation by the targeted arrangement of the outlet openings, which are arranged as nearest neighbors.
The material is preferably present as an endless strand on the conveyor belt and has two surface sides, wherein one of these surface sides rests on the conveyor belt and has at least two edges in the production direction.
In a preferred manner, the angle between the main axes of the outlet openings is chosen to be less than or equal to 180 °, preferably less than or equal to 90 °.
Alternatively or in combination, the angle between the connecting line of the centers of gravity of the surfaces of the outlet openings is selected to the vertical to the production direction less than 90 °. The measurement of the angle of the connecting line of the centers of gravity of the surfaces of the outlet openings can be carried out from the perpendicular to the production direction to the connecting line as well as from the connecting line to the perpendicular to the production direction.
Particularly preferably, the main axes of the outlet openings are perpendicular to each other. This "pattern" of the outlet openings, which are arranged as nearest neighbors, on the one hand can be limited only locally, but also be arranged in the entire continuous furnace.
In a preferred embodiment, a press is downstream of the continuous furnace in the production direction. The transport distance between the continuous furnace and the press should be as short as possible, whereby the material suffers only a minimal heat loss.
Alternatively or in combination, the device may be suitable for the continuous production of materials, preferably for the production of material plates. Under material boards are understood in particular wood-based panels such as chipboard, fiber or OSB boards, but also plastic plates or other plates, which can be produced by means of a press, in particular by means of a continuous press. Especially in the production of material plates in a continuous press allows a homogenously heated by the device for heating starting material faster compression of the material by an increased speed of the conveyor belt or the press can be made shorter in itself.
Alternatively or additionally, a control or regulating device for controlling individual or grouped magnetrons is arranged in order to operate these with different powers for producing a differentiated power profile, preferably in and / or transversely to the production direction. The microwave input can thus be controlled or regulated not only on the arrangement of the outlet openings, but also on the performance.
Advantageously, the outlet openings of the waveguide are arranged in one or more planes parallel or at an angle to the plane of the conveyor belt.
Preferably, round, square, rectangular and / or oval waveguides are arranged with corresponding outlet openings. Only waveguides of a cross section or a variety of outlet openings, but also different waveguides can be mixed.
Alternatively or additionally, the outlet openings are arranged longitudinally and transversely to the production direction in rows and tracks. It can thus be a global or regular arrangement of the outlet openings, which is interrupted locally by the arrangement of the outlet openings at an angle of their semi-axes or the line connecting the centers of gravity perpendicular to the direction of production.
In a further embodiment, the control or regulating device is suitable to retrieve predetermined power profiles based on the material and / or the product to be manufactured and set in the continuous furnace.
Preferably have the magnetrons have a different performance. Depending on the material, it may be advantageous, in particular from an energetic point of view, to equip individual magnetrons with lower power in advance.
Preferably, magnetrons with a power of 0.5 to 20 kW, preferably up to 6 kW, arranged.
Alternatively or in combination, a passive and / or active distribution means for the electromagnetic waves is arranged in the radiation space. In this way, a further homogenization of the distribution of the waves can be achieved, which ultimately beneficial effect on the heat input into the material.
In a further embodiment, outlet openings are arranged rotatably manually or by means of the control and regulating device. This allows targeted control of the outlet openings and thus the energy input into the material. This opens up the possibility that the material may change during the process and the device can be changed accordingly adapted to the new material without set-up times.
Reference to the accompanying drawings, details and embodiments of the invention will be explained in more detail.
In the drawings shows:
1 schematic side view (top) and an associated schematic plan view (bottom) of a device with a guided in the direction of production through a continuous furnace and a double belt press strand of material,
2 is a plan view of the lid of the radiation space of the continuous furnace with an exemplary arrangement of the waveguide,
Fig. 3 shows a section X3 in the production direction of Figure 2 through the radiation space and
Figure 1 shows above a schematic side view and below an associated schematic plan view of a device with a production direction 15 through a continuous furnace 1 and a continuously operating press 2 with two endlessly rotating and the strand-like material 3 by the press 2 pulling steel strips. The material 3 is transported on a conveyor belt 10 from the left through the continuous furnace 1, there heated in a radiation space 14, passed the press 2 and there pressed into a product 8 and cured.
Depending on the embodiment of the device can be arranged for a higher efficiency not only from an upper or lower surface side of a radiation chamber 14, but also from the other surface side a radiation chamber 14 ', the material 3 to apply microwaves. This may be necessary in particular if, due to the lack of penetration of the microwaves from one side, the material 3 can not sufficiently heat through or if the power for heating purposes is to be increased. The continuous furnace 1 has around the radiation space 14 in addition to a shielding housing 11 nor absorber 12, the inlet and outlet side absorb excess microwaves and prevent the leakage of microwaves from the continuous furnace 1 in addition to the only indicated there locks. To adapt to different heights and widths of the continuous material 3, the locks and / or the absorber 12 are height and / or width adjustable.
The device may include a control device 17 capable of driving the plurality of magnetrons 4 to produce microwaves in their power. In particular, it is provided that the control or regulating device 17 can control individual or grouped magnetrons 4. Preferably, the control or regulating device 17 is in operative connection with a storage device and / or a computing unit that already contains prescriptions or predetermined frame data for setting the continuous furnace 1 or the magnetrons 4. In particular, calculation bases can be stored here on the basis of which the control or regulating device 17, in conjunction with inputs of the operating personnel with respect to the type of material 3 and / or the product 8 to be produced, realizes proposals or settings with which the continuous furnace 1 in conjunction with the following Press 2 can work in an optimal and harmless for the material 3 area.
In an alternative or combining embodiment 15 measuring devices 16 can be arranged in front of the continuous furnace 1, measuring devices 18 after the continuous furnace 1 and in front of the press 2 for the material 3 in the production direction. Alternatively or in combination, it may be provided to arrange a measuring device 20 for the product 8 at the outlet of the press 2. All these mentioned or possibly further measuring devices have in common that they are in operative connection with the control or regulating device 17 and can transmit their measurement results to them. These measurements are the basis for control or regulating algorithms and causes in the control or regulating device 17 the generation and transmission of corresponding control commands to the continuous furnace 1 or the magnetrons 4 arranged there.
Alternatively or in combination, further preceding devices of the production site or the control station of the installation for transmitting data may be in operative connection with the control or regulating device 17.
These measuring devices 16, 18, 20 may preferably be suitable for making measurements in sections over the width 19 of the material 3 or of the product 8.
As can be seen further from FIG. 1, the material 3 is applied to the conveyor belt 10 in a height which is small relative to the width 19. Preferably, the material 3 is pressed in this width 19 in the subsequent press 2 to the product 8. The material 3 is therefore preferably strand-shaped, has an upper and a lower surface side, wherein a surface side rests on the conveyor belt 10 and forms two edges 7.
Figure 2 shows a plan view in the production direction 15 from bottom to top on the cover 22 of the radiation space 14 in a section X2-X2 of Figure 3. Figure 3 shows the corresponding view of a section X3-X3 through the radiation space 14 of Figure 2, wherein the Production direction 15 is directed to the drawing plane.
The combination of the two FIGS. 2 and 3 results in the following embodiment of the radiation space 14. The magnetrons 4 are preferably arranged separately in a cabinet 13 and laterally of the radiation space 14 for better accessibility, in particular for maintenance or replacement purposes. The cabinet 13 has openings through which the waveguides 5 connected to the magnetrons 4 guide the microwaves to the radiation space 14 and enter them there via the outlet openings 6, corresponding to openings in the lid 22 into the radiation space 14. In the plan view, it can be seen that the outlet openings 6 are arranged in several rows R (R n , R n + 1 ) transversely to the production direction 15 and tracks S (S n , S n + 1 ) along the production direction 15.
The manner of arrangement of the outlet openings 6 on the radiation space 14 is dependent on the use of the continuous furnace 1, the frequency of the microwave radiation, which has an influence on the size of the waveguide 5 and thus on the outlet openings 6, and in particular of the It may therefore be possible to use only a small number of magnetrons 4, wherein at least two must be arranged. These then form a row in any direction. Preferably, however, it is provided that at least a plurality of magnetrons 4 are arranged in a row R and can be controlled by means of the control or regulating device 17 with a differentiated power profile 9. Already a row R, if necessary not necessarily transverse but angular (except parallel) to the production direction allows the differentiated heating of the material 3 across the width 19.
Furthermore, the main axes 23 of two outlet openings 6 are shown by way of example in FIG. 2 in the lower left corner. In this exemplary embodiment, the main axes 23 of the rectangular outlet openings 6 form an angle of 90 ° to each other. Seen from the lower left outlet opening 6, the outlet opening 6 arranged next door in the same row R1 forms the next neighbor transversely to the production direction 15; the outlet opening 6 arranged in the row S2, in which the main axis 23 is drawn, forms the next neighbor in the production direction 15 ,
Also shown by way of example in FIG. 2 in the upper right-hand corner are two adjacent outlet openings 6 whose centers of gravity 24 (represented by dots) of the surfaces of the outlet openings 6 are connected to the connecting line 25. This connection line 25 encloses an angle to the perpendicular to the production direction 15.
According to FIG. 3, a second radiation space 14 'can be provided, the first radiation space 14 being arranged opposite to the material 3 and thus below the conveyor belt 10. This can preferably have the same configuration of magnetrons / waveguides / outlet openings as the radiation space 14. The material 3 to be heated here has a predetermined width 19 and lies on the moving through the continuous furnace 1 conveyor belt 10. The material 3 is formed substantially strand-shaped has two surface sides and one edge 7 each.
LIST OF REFERENCE NUMBERS
1 continuous furnace
2 press
3 material
4 magnetrons
5 waveguides
6 outlet opening
7 edge
8 product
9 performance profile
10 conveyor belt
11 housing
12 absorbers
13 cabinet
14 radiation room
15 production direction
16 measuring device
17 control or regulating device
18 measuring device
19 width
20 measuring device
21 longitudinal center line
22 lids
23 main axis
24 focus
25 connecting line
R row of outlet openings across 15
S trace of the outlet openings in FIG. 15
L power of 4

Claims

Apparatus for continuously heating materials of substantially non-metallic material, comprising

a continuous furnace (1) for continuous heating of material (3) on an endlessly circulating conveyor belt (10)

wherein the continuous furnace (1) has a plurality of magnetrons (4) for generating electromagnetic waves and waveguides (5) with outlet openings (6) for feeding the waves into a radiation space (14),

wherein the outlet openings (6) of the waveguide (5) have a major axis

characterized in that

at at least two outlet openings (6) which are arranged in and / or transverse to the production direction (15) as the nearest neighbor, the main axes (23) of the outlet openings (6) enclose an angle greater than 0 ° and / or the connecting line (25) of Focal points (24) of the surfaces of the outlet openings (6) forms an angle greater than 0 ° to the perpendicular to the production direction (15).
Apparatus according to claim 1, characterized in that the angle between the main axes (23) of the outlet openings (6) is less than or equal to 180 °, preferably less than or equal to 90 °.
Apparatus according to claim 1 or 2, characterized in that the angle between the connecting line (25) of the centers of gravity (24) of the surfaces of the outlet openings (6) to the perpendicular to the production direction (15) is less than 90 °.
Device according to one or more of the preceding claims, characterized in that the main axes (23) of the outlet openings (6) are perpendicular to each other.
Device according to one or more of the preceding claims, characterized in that in the direction of production (15) a press (2) is connected downstream.
Device according to one or more of the preceding claims, characterized in that the device is suitable for the continuous production of materials, preferably for the production of material plates.
Device according to one or more of the preceding claims, characterized in that a control or regulating device (17) for controlling individual or grouped magnetrons (4) is arranged to provide these with different powers (L) for producing a differentiated power profile (9), preferably in and / or transverse to the production direction (15) to operate.
Device according to one or more of the preceding claims, characterized in that the outlet openings (6) of the waveguide (5) are arranged in one or more planes parallel or at an angle to the plane of the conveyor belt (10).
Device according to one of the preceding claims, characterized in that round, square, rectangular and / or oval waveguide (5) with corresponding outlet openings (6) are arranged.
Device according to one of the preceding claims, characterized in that the outlet openings (6) are arranged longitudinally and transversely to the production direction (15) in rows (R) and tracks (S).
Device according to one or more of the preceding claims, characterized in that the control or regulating device (17) is suitable starting from the material (3) and / or the product to be produced (8) to call predetermined power profiles (9) and in a continuous furnace (1). adjust.
Device according to one or more of the preceding claims, characterized in that the magnetrons (4) have different powers.
Device according to one or more of the preceding claims, characterized in that magnetrons (4) are arranged with a power of 0.5 to 20 kW, preferably up to 6 kW.
Device according to one or more of the preceding claims, characterized in that a passive and / or active distribution means for the electromagnetic waves is arranged in the radiation space (14).
Device according to one or more of the preceding claims, characterized in that the outlet openings (6) are arranged rotatable manually or by means of the control and regulating device (17).