EP3130436B1 - Air spreading device - Google Patents

Description

The invention relates to a wind scattering device for spreading of grit on a grit conveyor, with at least
a wind ramming chamber, which has an upper grit opening, via which grit is introduced into the wind raking chamber,
one or more fans for generating air streams for the separation of the scattering material in the windbreak chamber,
an air supply housing (between the fans and the windbreak chamber) through which the air flows generated by the fans are directed into the windbreak chamber and
an adjoining in the flow direction of the air supply housing nozzle unit,
wherein the nozzle unit comprises a nozzle chamber having a plurality of outlet nozzles arranged in columns and rows.

Such a (wind) spreader is usually integrated into a grit plant for the production of grit mats for the production of material plates, in particular wood-based panels. Wood-based panels in particular means chipboard made of wood chips. In principle, however, fibreboards are also made of wood fibers. The spreading material mats sprinkled on the spreading material conveyor (eg spreading belt conveyor) are B. in a press, for example, a continuous working press or a cycle press, using pressure and heat to wood-based panels pressed. The quality of the wood-based panels produced depends decisively on the quality or the properties of the spreading material mats generated by the spreading device. The grit is usually glued grit, z. B. glued chips that are fed from a grit bunker or dosing hopper of the spreader.

In this case, a grit plant can have a plurality of scattering devices or scattering heads, in particular if multilayer grit mats of two outer layers (of fine material) and one middle layer (of coarse material) are to be produced. The individual scattering devices are then arranged one behind the other along the conveying direction of the scattering belt conveyor, so that initially a first covering layer is scattered onto the scattering belt conveyor, then the middle layer onto the first covering layer and then again the second covering layer onto the middle layer. The wind scattering device according to the invention is particularly preferably used for the production of cover layers within such a grit plant. Because of the air stream generated in the wind rattle chamber, the swarf chamber separates the chips, whereby coarser chips fall down in the vicinity of the nozzle unit and finer chips in the rear area, d. H. fall in the nozzle unit facing away from the area of the windstrike chamber. In this way, depending on the orientation of the scattering device relative to the transport direction of the scatter band conveyor, cover layers can be produced whose chip size becomes finer in the direction of the surface of the mat. In addition, one or more flying spine screens may be disposed in the windstrike chamber to optimize separation.

From practice, an embodiment of the type described is known, in which the air flow is adjustable within certain limits. These can z. B. be provided two fans arranged side by side are and therefore act on two different width ranges of the nozzle unit. Manually adjustable valves can be integrated in the air supply housing to adapt the air distribution to the conditions and thus to vary the distribution of the material to be spread over the width of the mat. The known from practice spreader has basically proven, but it is capable of further development.

From the DE 198 35 419 A1 discloses the preamble of claim 1, one knows a wind scattering device, in which a plurality of vertically arranged perforated plates are integrated into the air supply housing, which acts as a diffuser. About the last in the flow direction of the perforated plate, the air is supplied to the scattering chamber and there the particles introduced from above are spotted by the air currents according to the trajectories according to their size and fall on the Streubandförderer.

The DE 10 2007 056 109 A1 describes a wind scattering device in which a plurality of diffuser plates are arranged in the air supply housing, which is arranged between the fan and the windbreak chamber. In the flow direction behind the diffuser plates adjustment flaps are arranged with which the quantity distribution of the air flow in height is adjustable. The air distribution across the width can be influenced by vertically adjustable registers.

Another embodiment of a wind diffuser device is known from EP 1 889 702 A2 known.

The invention has for its object to provide a wind diffuser of the type described above, with which in an economical manner grit mats are produced in high quality.

To solve this problem, the invention teaches according to a first aspect, that the outlet nozzles each funnel-shaped in the flow direction of a rectangular, z. B. taper square input section into a round or oval output cross-section. By these measures, a particularly uniform air flow can bring into the Windstreugutkammer, at the same time very low pressure losses. The design of the outlet nozzles with a rectangular inlet cross-section reduces possible baffles for the air, since only narrow webs remain between the individual rectangular inlet cross-sections. This rectangular inlet cross-section is then funnel-shaped in a round or oval output cross-section, which ensures a uniform entry of the air flow in the windbreak chamber. The outlet nozzles with round exit cross-section are very easy to clean and also the funnel-shaped transitions from the rectangular cross section to the round cross section allow easy cleaning, as the particles can not settle in "corners". The nozzle chamber with the outlet nozzles may be of one or more plates, e.g. B. aluminum plate (s) are formed, in which the nozzles are formed or incorporated.

In the context of a second aspect of the invention, which has independent significance, the nozzle unit has a register unit arranged downstream of the distribution chamber, which has a plurality of register strips adjacent to one another, which have a plurality of openings assigned to the outlet nozzles distributed over the height and for adjustment variable outlet cross sections of the nozzle unit are height adjustable. So can be z. B. set over partial coverage of the output cross-section with the register strip variable outlet cross-sections, so that over the width of the nozzle unit, the air currents can be variably adjusted. Preferably, the adjustable by displacement remain resulting openings always centric to the outlet nozzles. In such an embodiment with register strips, the invention now proposes that the register unit has a plurality of register strips arranged one behind the other in the flow direction, wherein the register strips of the individual planes are independently adjustable in height relative to one another and / or relative to the output cross sections of the outlet nozzles.

Consequently, according to this second aspect of the invention, with the aid of the height-adjustable register strips, it is not only possible to vary the air distribution over the width of the register unit, but also to manipulate the air distribution over the height in a targeted manner. So z. For example, a first level with first register strip and a second level with second register strip may be provided, wherein the first register strip and the second register strip have openings with at least partially different extension. So it may be z. B. be useful to provide the first register strip in at least a first height range with first openings having a first height extent, z. B. round openings. This height extent corresponds to the output cross sections of the nozzles. In a second height range second openings with a contrast greater height extent, z. B. slot-shaped or oval openings may be provided. If such a first register strip is adjusted in height, then only a reduction of the outlet cross sections in the region of the first (round) openings takes place. The slot-shaped second openings have such a large height extent that the output cross sections of the outlet nozzles remain free and consequently the outlet cross sections are not reduced.

Accordingly, second register strips can be provided, in which the ratios are designed such that in the course of Height adjustment of these register strips the outlet cross sections are varied in other height ranges.

These possibilities then exist variably across the width, because the individual register strips distributed over the width can each be adjusted in height separately so that the air distribution over the height can be varied in the corresponding width range and consequently in the corresponding column. Details are explained by way of example in the description of the figures.

In any case, according to this second aspect of the invention, which assumes independent significance, the air flows can not only vary across the width, but it is also possible to variably set the flow conditions in different height ranges of the nozzle unit. These adjustment possibilities can be further expanded by providing a plurality of fans which supply different height ranges of the nozzle unit. Particularly preferably, at least four fans can be provided, two of which are associated with fans in an upper area of the nozzle unit and two fans in a lower area of the nozzle unit.

The register strips according to the invention can be implemented particularly preferably in an embodiment in which the outlet nozzles are configured funnel-shaped in the manner described. However, these two aspects of the invention can also be implemented independently of each other.

In a preferred development, the nozzle unit has a plurality of outlet tubes assigned to the outlet nozzles with a predetermined length, which are arranged downstream of the register unit. Consequently, a field or a matrix of outlet pipes adjoins the nozzle field or the nozzle matrix in an aligned manner, so that the air from the outlet nozzles via the register unit does not get directly into the windbreak chamber, but is first passed through the outlet pipes. These outlet tubes preferably have a round cross section which is aligned with the round outlet cross section of the outlet nozzles. This avoids turbulences and thus pressure losses.

In a preferred embodiment, the fans each produce vertically oriented air streams. In this case, the air supply housing is formed as a deflection housing with a vertical housing portion, a horizontal housing portion and a deflecting portion arranged therebetween. Consequently, the vertical air flows pass from the fans via the vertical housing section into the deflection section where they are deflected by 90 ° into the horizontal. The fans can preferably be designed as axial fans. In an advantageous embodiment, in the air supply housing, z. B. in the vertical housing portion one or more baffles arranged, which are aligned parallel to the flow direction and extending along the flow direction. Such baffles are particularly preferably arranged in the vertical housing section immediately below the fans. Optionally, one or more diffuser plates (eg perforated plates, perforated plates or the like) may be arranged in the air feed housing, which are preferably oriented transversely to the flow direction, so that the air flow passes through the diffuser plate. A first diffuser plate can, for. B. be arranged in the vertical housing portion below the baffles, wherein such a diffuser plate is then aligned horizontally. A second diffuser plate can, for. B. be arranged in the horizontal housing portion behind the deflection, in the flow direction in front of the nozzle unit. Such a diffuser plate is z. B. oriented vertically.

It is also within the scope of the invention that the air supply housing is provided with one or more closable maintenance openings. So z. B. on both sides of the Umlenkgehäuses, z. B. in the horizontal housing section maintenance openings may be provided as a manhole openings through which the nozzle unit of the air supply housing facing rear side is easily accessible, so that z. B. makes the nozzle unit easy to clean.

The scattering device according to the invention is characterized inter alia by the fact that pressure losses in the entire arrangement are significantly reduced, through the optimized flow paths. This leads to a significant reduction in the power consumption of the system and thus to a particularly economical operation. In addition, due to the variable setting options, an individual adaptation to different conditions is possible, so that the operation can be optimized. In particular, very uniform or homogeneous flows can thus be generated in the chamber.

The invention also provides a grit plant for the production of grit mats for the production of the material plates, in particular wood-based panels with at least one spreader of the type described and with at least one grit hopper above the spreader and a scatter band conveyor below the spreader. The wind scattering device according to the invention is consequently not only isolated, but in particular also placed under protection as part of a grit plant.

Fig. 1

eine Streugutanlage mit einer erfindungsgemäßen Streuvorrichtung in einer vereinfachten Seitenansicht,

Fig. 2

einen Ausschnitt aus einer solchen Streugutanlage in einer vereinfachten perspektivischen Darstellung,

Fig. 3

einen vergrößerten Ausschnitt aus dem Gegenstand nach Fig. 2 in einer anderen Ansicht,

Fig. 4

einen anderen vergrößerten Ausschnitt aus dem Gegenstand nach Fig. 2,

Fig. 5

einen Vertikalschnitt durch den Gegenstand nach Fig. 2 (Ausschnitt),

Fig. 6

einen Horizontalschnitt durch den Gegenstand nach Fig. 5,

Fig. 7

einen Vertikalschnitt durch den Gegenstand nach Fig. 5,

Fig. 8

einen vergrößerten Ausschnitt aus dem Gegenstand nach Fig. 5,

Fig. 9

einen Querschnitt durch die Düsenkammer nach Fig. 2 und

Fig. 10

eine Frontansicht auf einen Bereich der Düsenkammer nach Fig. 9.

In the following the invention will be explained in more detail with reference to a drawing showing only one exemplary embodiment. Show it

Fig. 1

a grit plant with a scattering device according to the invention in a simplified side view,

Fig. 2

a detail of such a grit plant in a simplified perspective view,

Fig. 3

an enlarged section of the object after Fig. 2 in another view,

Fig. 4

another enlarged section of the object Fig. 2 .

Fig. 5

a vertical section through the object Fig. 2 (Detail)

Fig. 6

a horizontal section through the object Fig. 5 .

Fig. 7

a vertical section through the object Fig. 5 .

Fig. 8

an enlarged section of the object after Fig. 5 .

Fig. 9

a cross section through the nozzle chamber after Fig. 2 and

Fig. 10

a front view of an area of the nozzle chamber after Fig. 9 ,

In Fig. 1 is a grit plant for the production of grit mats for the production of wood-based panels, especially chipboard represented. This grit plant has a grit hopper 1, which serves as a dosing bunker is formed and the grit z. B via spreading rollers or metering rollers 2 to a spreader 3 emits. With the spreader 3, the spreading material is scattered on the scattering belt conveyor 4, on which forms a grit mat, which then in a press using pressure and heat to a wood-based panel, z. B. chipboard is pressed. Such a grit system generally has a plurality of scatterers, to produce multiple layers of a grit mat, z. As outer layers and a middle layer, on. In Fig. 1 By way of example only an area with a scattering device 3 for producing a cover layer of relatively fine chips is shown. This scattering device 3 is designed as a wind scattering device. It has a Windstreukammer 5, which has an upper grit opening 6, via which the grit from the grit hopper 1 enters the Windstreukammer 5. In addition, the scattering device 3, a plurality of fans 7 for generating air streams for the separation of the material to be spread in the windbreak chamber. Between the fans 7 and the windbreak chamber 5, an air supply housing 8 is arranged, through which the air flows generated by the fans 7 are directed into the windbreak chamber 5. By the air currents in the Windstreukammer 5, the separation of the chips takes place, with coarser chips in the air supply housing 8 facing area of Windstreukammer 5 fall down (for the inner Deckschickt) and finer chips in the air supply housing 8 facing away from the rear portion of Windstreukammer 5 fall down (for the outer cover layer). In addition, sieves 9 (flight saws), which are arranged transversely to the direction of flow and are equipped with vibrators and ensure optimum chip distribution and precise granulometric separation, can be arranged in the windscreen chamber 5 in basically known manner. For Grobgutaustrag a roller screen 10 with discharge screw 11 is provided below the trajectory. Alternatively to the illustrated embodiment, however, instead of the roller screen and a vibrating screen be provided. About the roller screen 10 and a corresponding vibrating screen z. B. glue lumps are retained, which can then be removed with the discharge screw 11.

In the flow direction, the air supply housing 8 is followed by a nozzle unit 12, which consequently forms the transition between the air supply housing 8 and the windbreak chamber 5. The air streams thus end up coming out of the air supply housing through the nozzle unit 12 and from there into the windbreak chamber 5.

This nozzle unit 12 has a nozzle chamber 13 with a plurality of outlet nozzles 14 arranged in columns and rows. These outlet nozzles 14 taper in a funnel shape in the flow direction and pass from a rectangular inlet cross-section E into a round outlet cross-section A. This is z. In Fig. 4 as well as in the FIGS. 9 and 10 shown. It can be seen that only very narrow webs 15 are arranged from the direction of the air supply housing 8 between the individual outlet nozzles 14, which provide minimal resistance to the air flows.

In addition, the nozzle unit 12 has a register unit 16 arranged downstream of the nozzle chamber 13 in the flow direction, which has a plurality of register strips 17a, 17b which are associated with the columns and have a plurality of openings 18a, 18b assigned to the outlet nozzles 14 distributed over the height. For setting variable outlet cross sections of the nozzle unit 12, these register strips 17a, 17b are height adjustable. This means that the air flows are not always over the full outlet cross section of the outlet nozzles, but - depending on the setting of the register strips 17a, 17b - Where appropriate, exit via a relative to the output cross-section A reduced outlet cross-section.

The figures show that the register unit 16 has several planes of register strips 17a, 17b arranged one behind the other in the flow direction. The register strips 17a and 17b of the two planes are independently adjustable in height relative to the output cross sections A of the outlet nozzles 14. Thus, first register strips 17a are provided in the first plane and second register strips 17b in the second plane. Thus, distributed over the width of the nozzle unit 12, both a plurality of first register strips 17a and a plurality of second register strips 17b are distributed, wherein the first register strips 17a and the second register strips 17b are arranged one behind the other in the flow direction (in pairs). In particular in Fig. 8 It can be seen that the first register strips 17a on the one hand and the second register strips 17b on the other hand have openings 18a, 18b with different expansion.

Thus, the first register strips 17a have round openings 18a in the lower area and slot-like openings 18b in the middle area and in the upper area. If such a first register strip 17a is adjusted vertically, then the outlet cross section is influenced only in the region of the lower outlet nozzles 14, while the outlet cross section is not influenced in the middle region and in the upper region, since the elongated holes 18b have a relatively large height extent (greater than having the output cross sections A). Consequently, with the aid of these first register strips 17a, the air streams in the lower region of the nozzle unit can be manipulated and set to the desired conditions, in principle distributed individually over the width for each individual register strip 17a.

On the other hand, the second register strips 17b have slot-like openings 18b in the lower area and also slot-like openings 18b in the upper area and round openings 18a in the middle area therebetween. Consequently, with the aid of these second register strips 17b, the outlet cross sections in the middle region of the nozzle unit 12 can be manipulated. Consequently, in the illustrated embodiment, the flow conditions in the lower region and in the middle region can be adjusted independently of one another and independently of the upper region via the two register strips 17a, 17b. In this embodiment, no manipulation in the upper region of the nozzle unit 12 is possible via the register strip.

Basically, however, it is within the scope of the invention to provide not only two levels, but three or more levels of register strip, so that a very variable adjustment of the flow conditions is possible.

The register strips 17a, 17b are arranged on a common carrier 19, which is provided with corresponding adjusting means 20, on the one hand for the first register strip 17a and on the other hand for the second register strip 17b. The adjustment is done manually, z. B. in the course of commissioning, z. B. screws, spindles or the like, but can also be provided with adjustable drives.

Furthermore, it can be seen in the figures that the nozzle unit 12 has a multiplicity of outlet tubes 21 which are assigned to the individual outlet nozzles 14, the outlet tubes 21 being arranged downstream of the register unit 16 in the flow direction. The outlet tubes have a round cross-section which is aligned with the outlet cross-sections A of the outlet nozzles 14. From these outlet pipes 21, the air enters the windbreak chamber 5 a.

Incidentally, it can be seen in the figures that the fans 7 generate vertically oriented air flows. The fans 7 are formed in the embodiment as axial fans. The air supply housing 8 is formed in the embodiment as Umlenkgehäuse. It has a vertical housing section 22 and a horizontal housing section 24 and a corresponding deflection section 23 therebetween. Consequently, in the deflection section 23, the air flows are deflected by 90 ° from the vertical to the horizontal.

The flow conditions can be further optimized by the use of baffles 25 and the diffuser plates 26a, 26b. Thus, in the vertical housing sections 22, which are each associated with the individual fans 7, baffles 25 are arranged, which are aligned approximately parallel to the flow direction and are therefore aligned in the embodiment in the vertical direction. Below these baffles 25, the diffuser plates 26 are arranged, which are aligned horizontally.

In addition, in the horizontal housing portion 24, a further diffuser plate 26 is arranged, which is vertically aligned.

Incidentally, the air supply housing 8 is provided on both sides with maintenance openings, which are not shown in the figures. About these maintenance openings, which are relatively large formed as manhole openings, the nozzle unit 12 is accessible for maintenance purposes and in particular cleaning purposes.

In the exemplary embodiment, the nozzle unit 12 has thirty columns arranged next to one another and seventeen rows arranged one above the other. The upper fans supply the upper twelve rows and the lower fans supply the lower five rows. Via the first register strips 17a, the outlet cross sections of the lower five rows can be manipulated, and the middle six rows can be manipulated via the second register strips 17b.

Claims (14)

1. Air spreading device (3) for spreading dispersed material onto a dispersed material conveyor (4) with at least
   one air spreading chamber (5) which has an upper dispersed material opening (6) via which dispersed material is introduced into the air spreading chamber (5),
   one or more fans (7) for producing air flows for separating the dispersed material in the air spreading chamber (5),
   an air in-feed housing (8) through which the air flows produced by the fans (7) are directed into the air spreading chamber (5) and
   a nozzle unit (12) adjoining the air in-feed housing (8) in the flow direction,
   wherein the nozzle unit (12) comprises a nozzle chamber (13) with a plurality of outlet nozzles (14) arranged in columns and rows,
   characterised in that
   the outlet nozzles (14) each taper in the flow direction in a funnel-like manner from a rectangular inlet cross-section (E) into a round or oval outlet cross-section (A).
2. Device according to claim 1, wherein the nozzle unit (12) has a register unit (16) arranged after the nozzle chamber (13) in the flow direction which comprises several adjacent register strips (17, 17a) assigned to the columns which each have, distributed over their height, several openings (18a, 18b) which are assigned to the outlet nozzles and to set variable outlet cross-sections of the nozzle unit (12) are adjustable in height, characterised in that the register unit (16) comprises a plurality of planes of register strips (17a, 17b) arranged on behind the other in the flow direction, wherein the register strips (17a, 17b) of the individual planes are height-adjustable independently of each other relative to each other and/or relative to the outlet cross-sections (A) of the outlet nozzles (14).
3. Device according to claim 2 characterised in that first register strips (17a) are provided in a first plane and second register strips (17b) in a second plane, wherein the first register strips (17a) and the second register strips (17b) have openings (18a, 18b) with at least partially different dimensions.
4. Device according to claim 3 characterised in that the first register strips (17a) in at least one first height area have first openings (18a) with a first height dimension and in at least one second height area second openings (18b) with a second height dimension.
5. Device according to claim 3 or 4 characterised in that the second register strips (17b) in at least a first height area have first openings (18a) with a first height dimension and in a second height area have second openings (18b) with a second height dimension.
6. Device according to claim 4 of 5 characterised in that the first openings are designed as round openings and the second openings as elongated hole-shaped or oval openings or vice versa.
7. Device according to any one of claims 2 to 6 characterised in that the nozzle unit (12) comprises several outlet pipes (21) of predetermined length assigned to the outlet nozzles (14) which are arranged after the register unit (16).
8. Device according to any one of claims 1 to 7 characterised in that the fans (7) each produce vertically orientated air flows and in that the air in-feed housing (8) is designed as a deflecting housing with at least one vertical housing section (22), one horizontal housing section (24) and a deflecting section (23) arranged between them.
9. Device according to any one of claims 1 to 8 characterised in the in the air in-feed housing (8), e.g. in the vertical housing section (22) guide plates (25) are arranged.
10. Device according to any one of claims 1 to 9 characterised in that in the air in-feed housing (8) one or more diffuser plates (26a, 26b) are arranged.
11. Device according to any one of claims 1 to 10 characterised in that fans (7) are designed as axial fans.
12. Device according to any one of claims 1 to 11 characterise in that at least four fans (7) are provided, of which two fans (7) are assigned to an upper area of the nozzle unit (12) and two fans (7) are assigned to a lower area of the nozzle unit (12).
13. Device according to any one of claims 1 to 12 characterised in that the air in-feed housing (8) is provided with one or more lockable maintenance openings.
14. Dispersed material device for producing dispersed material mats for the production of material boards, in particular wood based boards, with an air spreading device (3) according to any one of claims 1 to 13 and with at least one dispersed material hopper (1) above the air spreading (3) and a dispersed material conveyor (4), e.g. dispersed material belt conveyor, under the spreading device (3).

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