ES2408968T3 - Procedure and equipment for mixing a mixture of particles with an adhesive - Google Patents

Abstract

Equipment for mixing a mixture of particles of different size of wood compound with an adhesive, which includes the following steps: (a) contribution of particles of different size to a flow in a mixing equipment (2), (b) gluing of particles of different sizes with an adhesive, the amount of high-size adhesive of the corresponding particle being adjusted, (c) mixing of the sized particles of different size, (d) evacuation of the mixed particles of different size in a protruding flow of the mixing equipment (2), particles of different sizes being transported in the mixing equipment (2) from a particle introduction equipment (8) to a particle discharge device (12) along a transport path, characterized in that The amount of adhesive introduced into the mixing equipment (2) varies along the transport path.

Description

Procedure and equipment for mixing a mixture of particles with an adhesive.

The invention relates to a method according to claim 1.

The invention further relates to a device according to claim 6.

In the manufacture of wood compounds, wood is crushed according to the desired application and bonded by means of an adhesive in a hot pressing process, for example to form an MDF (medium density fibers) or HDF (fiber fibers) plate. high density), of agglomerate or OSB (of oriented fibers). To do this, the chips or fibers must be coated with the adhesive. Particles that are not composed of wood, for example plastic particles, can also be added by mixing.

In this regard, the amount of adhesive used is one of the critical magnitudes of the process and with it the costs and therefore requires permanent optimization.

Traditionally, particles to be glued on one side are introduced by means of a device for introducing particles into a mixing equipment. With the help of the so-called mixing tools, the introduced equipment travels the mixing equipment to a particle discharge device, where they again leave the mixing equipment. Along this path, adhesive is introduced into the mixing equipment by means of an adhesive insertion device at various points, for example by means of nozzles, into the mixing equipment.

Here it is basically possible to provide various layers of the wood composite plates to be manufactured individually in separate mixing equipment. Thus, for example, it is usual to manufacture the cover layer of a chipboard from finer chips than those of the central layer, to improve both the appearance of the surface and also the roughness of the surface of the plate then finished.

However, even in this case a particle flow that is not composed of particles of a single size is mixed with the adhesive flow. The particle flow has a characteristic size distribution within a certain bandwidth, which has an unfavorable impact on the size of the different particles.

The amount of adhesive with which an individual particle is glued depends on its surface. In order to achieve the important mechanical characteristics in the subsequent wood composite plates, such as transverse tensile strength, flexural strength or shear strength, large chips and fibers are needed in particular. However, since they have a volume in relation to their surface that is clearly greater than small particles, such as fibers or dust, it has the subsequent composite plate or a cake with particles already spread before pressing, in the points where the large particles important for stability are found, an amount of adhesive clearly less than at the points where there are small particles that contribute less to stability. Due to the relationship between the volume of the particles and their surface, small particles are glued with a comparatively larger amount of adhesive than the large ones. In this way the large particles receive too little adhesive, and nevertheless in particular the fine part and the powder are provided with too much adhesive.

However, not only is the adhesive used distributed unfavorably between large and small particles, but it is also used as a whole too adhesive. The adhesive used is therefore not economically treated and the characteristics of the pressed plates from the particles thus glued never reach the optimum that can be achieved technically.

From EP 0 681 895 A1, equipment for mixing a mixture of particles and adhesive is known. In this equipment the particles are introduced in a mixing cylinder, in which the adhesive is also sprayed by means of inlet nozzles. However, the particles are previously selected by means of fractioning equipment. The light particles are then passed in front of the adhesive nozzles and are only introduced in the direction of transport behind these nozzles in the mixing cylinder. In this way these adhesive particles are not provided or only by contact with the large glued particles.

A similar system is known from DE 43 15 922 C1. Also here the particles to be glued are divided into a fractioning equipment into large and small particles. Large particles reach a mixing cylinder and are glued therein. Small and light particles are housed at different points along a transport path in the mixing cylinder and are glued only indirectly by contact with the large glued particles.

Also in DE 1 180 121, the particles to be glued in a fractionator are classified according to size and weight, before being glued in a mixing cylinder. This is done, for example, by a fan, which generates an air flow. In this air flow the particles to be glued fall from above and are deflected by the air flow, whereby they are accommodated depending on the size and weight at different points in the mixing cylinder.

A similar principle according to the preamble of claim 1 is followed by US 3,343,814. Also here the particles are subjected to glue to an air flow, whereby the light and small particles are diverted more strongly than the large and heavy particles. The particles fall accordingly at different points in a mixing cylinder, in which they are glued by means of gluing nozzles.

The invention therefore has as a basic task to further develop a method and equipment for mixing a mixture of particles of different size of wood compound with an adhesive such that a better distribution of the adhesive between the particles of different size is ensured.

Because all the particles, regardless of their size, are glued in the same mixing equipment, the cost of the procedure in apparatus is clearly reduced. Because despite the amount of adhesive that falls on the corresponding particles depends on the size of the particles, an optimal distribution of the adhesive is obtained. Both stages (b) and (c) can in particular also be carried out together, mixing the particles with each other for example in the mixing equipment, while adhesive is introduced into the mixing equipment. Then the particles of different size are mixed on one side with each other and on the other with the adhesive and thus glued.

Particles of different sizes are transported when intermingled in the mixing equipment in particular from a particle introduction device to a particle evacuation device along a transport path. Advantageously, small particles are not housed in the transport direction behind large particles in the mixing equipment. In particular, the adhesive is introduced into the mixing equipment along the entire transport path. In this way it is ensured that the small particles have to travel a shorter section within the mixing equipment along the transport path than the larger particles. When the adhesive is introduced along the entire transport path, for example by means of nozzles, they pass through the small particles, due to the shorter section they have traveled, less of these nozzles, so that they can also absorb less adhesive. The large particles, which cover the entire transport path within the mixing equipment, pass on the other hand in front of all the points where adhesive is introduced into the mixing equipment and can thus be optimally glued. The amount of adhesive that is housed in a partial section of the transport path can be adjusted freely, so that sizing factors dependent on particle size can also be achieved.

Preferably the particles of different size are glued according to their size for a different time in the mixing device. In particular, small particles are mixed for less time with the adhesive than large particles. Due to the long residence time of the large particles in the mixing equipment it is ensured that they are glued sufficiently, to subsequently obtain a characteristic of sufficient stability in a pressed plate from the particles. At the same time, the smaller particles, which are less important for these stability characteristics, are glued for the shortest period of time in which they are inside the mixing equipment. This results in optimum gluing, precisely approximately in a way that it seems that all particle sizes have been separately provided with adhesive. It is then possible to achieve a uniform sizing of all particles or a sizing factor dependent on the size of the particles and for example sizing large particles more intensely than small particles. This results in turn clearly better characteristics for the plates, using at the same time less amount of adhesive, since the important particles from the point of view of mechanical technology have a good quality of gluing and do not have a fairly low gluing, as in traditional procedures.

The density of particles of different sizes is preferably between 100 kg / m3 and 800 kg / m3.

A device corresponding to the invention for mixing a mixture of particles composed of particles of different sizes with an adhesive is a generic type device characterized in that the amount of adhesive to be applied on a part of the trajectory of the path can be freely adjusted. transport.

As explained above, an optimized distribution of the adhesive between large and small particles is ensured by the different duration of the permanence of the particles in the mixing equipment.

Within the mixing equipment a transport equipment is provided, whereby particles of different sizes housed in the particle introduction equipment can be transported to a particle discharge equipment along a transport path. The particle introduction equipment is configured in particular as introduction nozzles distributed along the transport path. In this way, the amount of adhesive introduced along the transport path can also be freely adjusted and varied.

The fractioning equipment is preferably arranged in the particle introduction equipment or in front of it in the processing direction. In this way it is ensured that particles of different sizes are introduced at different points of the transport path into the mixing equipment. Because the small particles are introduced in the transport direction after the large particles in the mixing equipment, they do not travel along the entire transport path and do not pass correspondingly through all the introduction nozzles of the adhesive introduction equipment. They can thus take less adhesive than large particles, which cover the entire transport path.

The fractioning equipment may also be arranged in the processing direction after the particle introduction equipment. In this case, particles of any size arrive at the same point of the mixing equipment. In this case, the fractioning equipment is configured such that it gives different sized particles different speeds along the transport path. Because in this case the smaller particles move faster along the transport path, their residence time in the mixing equipment is also reduced and it is ensured that they cannot take too much adhesive.

Preferably the fractionator is a fan. If this fan is arranged, for example, in the particle introduction equipment or in front of it in the manufacturing direction, a lateral air flow is conducted on the particle flow, the particles being separated on the basis of size and weight, as is done for example in a classic pneumatic separation procedure. In this regard, small particles and dust deviate more strongly than large particles. When the fan is positioned such that the air flow for example runs parallel to the transport direction, the smaller particles are carried in the transport direction later to the mixing equipment.

The fan can, however, also be disposed within the mixing equipment, that is, in the processing direction after the particle introduction equipment. Also in this case a lateral air flow is conducted on the particle flow, the particle accelerating preferably in the direction of transport. Then the smaller and lighter particles are accelerated more strongly than the large particles. They move accordingly faster than large particles in the direction of transport through the mixing equipment and thus take less adhesive.

The fractioning equipment can also be configured as a supported brush such that it can rotate. The supported brush such that it can rotate, which rotates when the equipment is operating, can also be arranged in the processing direction in front of or behind or directly inside the particle introduction equipment. Also, by means of the rotating brush, the different particles are accelerated preferably in the transport direction, the large particles accelerating less strongly, that is, flying a smaller distance. Also in this way it can be ensured that the smallest particles are introduced into the mixing equipment such that they no longer travel the entire transport path and thus can take less adhesive. By means of a launching device arranged inside the mixing equipment, in particular a rotating brush, drum or the like, it is ensured as in the fan that the particles are printed with a speed in the direction of transport that depends on their size.

The fractioning equipment preferably has a sieve. This sieve has in particular openings of different sizes. The placement of a sieve is particularly advantageous when the fractioning equipment is arranged inside or in the processing direction in front of the particle introduction equipment. In this way it can be ensured that large particles that inadvertently have been diverted too far in the transport direction are not introduced with the smaller particles in the mixing equipment, but slide back along the sieve preferably inclined and enter the mixing equipment at the point set for its size. In this way it is ensured that indeed all particles of a certain size travel along the section provided for them along the transport path within the mixing equipment.

The equipment corresponding to the invention and the process corresponding to the invention are therefore concerned with an optimized distribution of the amount of adhesive between the various particles of various sizes and are in particular suitable for all types of wood crushing products, such as for example fibers, chips or strands and with it also to manufacture the most diverse wood compounds, such as MDF or HDF, agglomerate or OSB plates. Naturally, particles not composed of wood, but for example of plastic, can also be provided with adhesive. Of course, mixtures of particles of different materials can also be made.

With the help of a drawing, various examples of execution of a device corresponding to the invention will be described below. In this regard, the same components of the same references have been provided in all figures.

It is shown in:

1 shows a schematic representation of a first exemplary embodiment of an equipment corresponding to the invention;

2 shows a schematic representation of a second example of execution of a device corresponding to the invention;

Figure 3 a schematic representation of a third exemplary embodiment of an equipment corresponding to the invention and

Figure 4 a schematic representation of a fourth example of execution of a device corresponding to the invention.

Figure 1 shows a schematic representation of a device according to a first exemplary embodiment of the present invention.

In a mixing equipment 2 there is a transport equipment 4 with an actuation unit 6. The transported particles 4 are transported from above by means of the transport equipment 4 by means of a particle introduction equipment 8 in the mixing equipment 2 along the transport direction F. Then they are intermingled by means of the transport equipment 4 and glued from above with adhesive by means of an adhesive introduction equipment in the form of gluing nozzles 10 that can be controlled and which are distributed evenly along the transport path The particles thus glued leave the mixing equipment 2 through a particle discharge equipment 12. The sizing nozzles 10 may also be irregularly distributed or be adjusted for different injection forces.

In the particle introduction equipment 8, a fractioning device 14 is provided, which in Figure 1 is only indicated as a schematic box. The fractioning equipment 14 is configured in Figure 1 as a fan, which blows along the air flow direction L an air flow to the particle introduction equipment 8. The particles falling from above to the particle introduction equipment 8 are deflected by this air flow in the direction of the air flow L, which is indicated by various arrows.

The light particles in Figure 1 are then deflected more to the left than the heavy particles and thus fall further to the left in the mixing equipment 2. The light particles fall by means of the funnel-shaped enlarged particle introduction equipment 8 behind the first gluing nozzles 10 seen in the transport direction F. All the particles that fall in the mixing equipment 2 are transported along the transport direction F in the direction of the particle discharge equipment by means of the transport equipment 4 12, the light particles being carried in front of fewer sizing nozzles 10. Thus, the light particles can only take a smaller amount of adhesive, which is introduced through the sizing nozzles in the mixing equipment 2. The heavy particles, that barely deviate or do not deviate at all by the air flow in the direction of the air flow L, pass through the contr In its trajectory towards the particle discharge equipment 12 all or most of the glue nozzles 10 provided are thus provided with more adhesive than the light particles.

Figure 2 shows a second exemplary embodiment of the present invention.

For the same components the same references were used as in Figure 1. Also here the particles are introduced by means of a particle introduction equipment 8 in a mixing equipment 2, in which they are transported by means of a transport equipment 4 at along the transport direction F in the direction of the particle discharge equipment 12, the same being carried ahead of gluing nozzles 10, through which the adhesive is introduced into the mixing equipment 2.

In Figure 2, a splitter device 14, configured as a fan, is provided on the right edge of the mixer 2. The fractioning equipment 14 is accordingly placed in Figure 2 inside the mixing equipment 2 and with it in the manufacturing direction behind the particle introduction equipment 8.

Contrary to Figure 1, all particles arrive here through the particle introduction equipment 8 to the same point in the mixing equipment 2. They are diverted by the air flow introduced by the fractioning equipment 14 along the air flow direction L in the transport direction F. Also here the light particles are accelerated with more intensity in the transport direction F than the heavy particles. In this way it is ensured that the light particles, at least in the first glue nozzles 10, fly ahead much faster than if they are only moved by the transport equipment 4 in the transport direction

F. In this way, the adhesive in the first glue nozzles 10 is extremely low. It is also ensured that large particles are optimally bathed with adhesive, since they are conducted in front of all the glue nozzles. 10 with the speed predetermined by the transport equipment 4. Since they, as also in Figure 1, are intermingled by the transport equipment 4, a glue with homogeneous adhesive is ensured on all sides of all particles.

Figure 3 shows a device according to a third embodiment of the present invention. Again the same references have been used for the same components. In figure 3 a fractioning equipment 14 is provided as in figure 1 in the manufacturing direction in front of the mixing equipment 2. As in figure 2 the fractioning equipment 14 is composed of a fan, actuated by means of a unit of fan drive 16. By means of the fractioning equipment 14 of Figure 3, an air flow is inflated along the direction of the air flow L into a particle insertion equipment 8. As in Figure 1, the particles introduced into the particle introduction equipment 8 by this air flow in the direction of the air flow L. Then the light particles are again deflected more strongly than the heavy ones. Inside the particle introduction equipment 8, a sieve 18 is arranged, through which the diverted particles must pass, to reach the mixing equipment 2. In this regard, the sieve 18 has sieve openings of different sizes (not shown). In Figure 3, the sieve 18 shows to the left the smallest sieve openings and to the right the largest sieve openings. By means of the air flow in the direction of the flow L, the light particles are diverted more strongly to the left and therein they affect the part of the sieve 18 which has the smallest sieve openings. The large particles are barely deflected by the air flow, or they are not at all, and they affect the right part of the sieve 18, which has the largest sieve holes.

If a relatively large particle was diverted to the left due to an uneven spreading or due to collisions between the particles such that it was too large for the sieve openings there in the sieve 18, it would slide along the sieve 18 down and thus reach the right side of sieve 18, where the openings of the sieve are sufficiently large. For this purpose, the screen 18 inclined in Figure 3 is arranged.

As in the embodiment of Figure 1, the small particles farther to the left in the direction of the air flow L also deviate in the embodiment of Figure 3 and therefore also fall further towards the left in the mixing equipment 2. There it continues transporting them by means of a transport equipment 4 in the transport direction F, then passing in front of the gluing nozzles

10. Because the small particles pass in front of less gluing nozzles 10 than the large ones, optimized gluing is ensured here.

The equipment shown in Figure 4 according to a fourth exemplary embodiment of the present invention differs from the equipment shown in Figure 1 in that the fractioning equipment 14 is not configured as a fan, but as a brush, drum or similar rotating. The direction of rotation is indicated by a curved arrow.

By means of the brush of the fractioning equipment 14 that rotates in the direction of the date, the particles housed in the introduction equipment of the particles 8 are diverted to the left. Also here it is fulfilled that the light particles fly beyond the heavy ones, with which are also introduced further to the left in the mixing equipment 2 and carried by means of the transport equipment 4 in front of less gluing nozzles 10.

In all the examples shown in Figures 1 to 4 it is thus ensured that the small particles are mixed for less time with the adhesive introduced by means of the gluing nozzles 10 than the large particles.

By means of devices corresponding to the invention it is thus ensured that the sizing factor of particles of different sizes can be controlled according to their size. For this, only one gluing equipment is necessary, saving time, space and costs.

Reference List

F transport direction L air flow direction 2 mixing equipment 4 transport equipment 6 drive unit 8 particle introduction equipment 10 glue nozzles 12 particle discharge equipment 14 fractionator equipment 16 fan drive unit 18 sieve

Claims (12)

1. Equipment for mixing a mixture of particles of different size of wood compound with an adhesive, which includes the following stages:

(to)

contribution of particles of different sizes to a flow in a mixing equipment (2),

(b)

 gluing the particles of different size with an adhesive, the amount of adhesive being adjusted to the size of the corresponding particle,

(C)

mixture of glued particles of different sizes,

(d)

 evacuation of mixed sized particles of different size in an outgoing flow of the equipment

mixer (2), the particles of different size being transported in the mixing equipment (2) from a particle introduction equipment (8) to a particle discharge equipment (12) along a transport path, characterized because the amount of adhesive introduced in the mixing equipment (2) varies along the transport path.

2.

Method according to claim 1, characterized in that the particles of different sizes are glued in the mixing equipment (2) for a different time depending on their size along a different length.

3.

Method according to claim 1 or 2, characterized in that the small particles are introduced in the transport direction (F) behind the large particles in the mixing equipment (2).

Four.

Method according to one or more of the preceding claims, characterized in that the adhesive is introduced along the transport path in the mixing equipment (2).

5.

Method according to one or more of the preceding claims, characterized in that the density of the particles is between 100 kg / m3 and 800 kg / m3.

6.

Equipment for mixing a mixture of particles composed of particles of different sizes with an adhesive, with a) a mixing equipment (2), b) a particle introduction equipment (8) to introduce particles of different size into the equipment

mixer (2), c) an adhesive introduction equipment (10), a fractioning equipment (14) being provided by means of which the particles of different sizes, during the operation of the equipment, remain for a different time in the mixing equipment and an equipment of transport (4) within the mixing equipment (2), by means of which particles of different sizes introduced can be transported to an equipment for unloading the particles (12) along a transport path, characterized in that the amount of adhesive that It can be provided on a section of the transport path, it can be adjusted freely and can vary along the transport path. 7. Equipment according to claim 6, characterized in that the adhesive introduction equipment is configured as introduction nozzles (10) distributed by the transport path.

8.

Equipment according to claim 6 or 7, characterized in that the fractioning equipment (14) is arranged in the particle introduction equipment (8) or, in the manufacturing direction, in front of it.

9.

Equipment according to claim 6 or 7, characterized in that the fractioning equipment (14) is arranged in the manufacturing direction after the particle introduction equipment (8).

10.

 Equipment according to one of claims 6 to 9, characterized in that the fractioning equipment (14) is a fan.

eleven.

 Equipment according to one of claims 6 to 9, characterized in that the fractioning equipment (14) is a launching device, in particular a brush, drum

or similar supported such that it can rotate. 12. Equipment according to one of claims 6 to 11, characterized in that the fractioning equipment (14) has a sieve (18), which has openings of different sizes.