ES2511846T3 - Installation for manufacturing wood-derived materials - Google Patents

Abstract

Installation for carrying out a process for manufacturing wood-derived materials from crushing products containing lignocellulose with a dryer (1), a sizing equipment associated with the dryer (1), which configures a shaped gluing area (12) cylindrical with a cross section and which is connected to the dryer (1) through a pipe (5), and a transport pipe (25) connected to the gluing area (12), presenting the transport pipe (25) a section larger than the glue zone (12) with a cylindrical shape and between an end of the glue zone (12) and the transport pipe (25) an interstitium (9), through which a flow of additional air in the transport pipe (25), characterized in that the annular gap (9) is configured such that a laminar air flow is configured in an inner wall of the transport pipe (25) and because in the pipe (5) is at least a turbulence valve (7), to rotate a flow of air flowing through the pipe (5).

Description

DESCRIPTION

Installation for manufacturing wood-derived materials

The invention relates to an installation according to claim 1 for carrying out a process for manufacturing wood-derived materials from crushing products containing lignocellulose with a dryer, a sizing equipment associated with drying, which configures a sizing area cylindrical in shape with a cross section and that is connected to the dryer through a pipe and a transport pipe connected to the gluing area, the transport pipe presenting a section larger than the glue zone with cylindrical shape and being between The end of the gluing zone and the transport pipe is an interstitium, through which an additional air flow can be introduced into the transport pipe.

A generic type device is known for example from EP 1 504 865 A2. After gluing the crushing products in the gluing equipment, an additional air flow is conducted to the glued fibers, with which the fibers are mixed uniformly. This results in a final drying of the fibers, since adding the glue to the fibers gives them water.

From EP 1 337 384 a process is known for preparing fibers before hot pressing them to form fiber plates, in which the fibers are dried first to a predetermined residual moisture and then glued. The transport from the dryer to the gluing equipment is then carried out by means of air pressure. The glue is directed to the dried fibers by sprinkling it through nozzles, whereby it is deposited in fine drops on the surface of the fibers. The glued fibers are then conducted through a connecting pipe to the next treatment stage, for example directly to a spreading machine. 25

The gluing zone in the material transport pipe is formed by an air-permeable inner tube with a pressure-tight outer shell. In the interstitium that results, pressurized air is introduced. At the same time, the glue or binder is sprayed through several nozzles and mixed with the flow of fibers through the inner tube. 30

EP 0 745 463 A2 discloses a process and equipment for manufacturing wood-derived materials from crushing products containing lignocellulose. In this regard, the crushing products are transported with a flow of transport air and mixed with an adhesive. If necessary, other additives may also be added. The adhesive mixture 35 with crushing products is then transported by another air flow to the next treatment station.

It is a disadvantage that the flow of glued fibers adheres to the inner wall of the transport pipe that follows the impregnation zone with glue. This transport pipe is soiled and its inner diameter is reduced. Therefore, such installations for dry gluing must be stopped from time to time and cleaned. This results, in addition to greater maintenance, also a greater cost.

The invention therefore has as a basic task to indicate an installation for manufacturing wood-derived materials in which the glued shredding products from the flow of material 45 to the transport pipe are prevented from adhering.

An installation corresponding to the invention for carrying out a process for manufacturing wood-derived materials from crushing products containing lignocellulose, is characterized in that the interstitium is configured such that next to an inner wall of the transport pipe a configuration is configured. laminar air flow. In this way it is ensured that the mixture of transport air and crushed products already glued does not make contact with the inner wall of the transport pipe. In particular, there are few whirlpools and turbulence in the area of the inner wall of the transport pipe that may lead to the contact of the crushed products glued with the inner wall. In the pipeline, at least one turbulence valve is found according to the invention, to turn a flow of air through the pipe. In this way it is guaranteed that the air flow rotates in the gluing area, thus avoiding adhesions of glued crushing products.

In this regard, the end of the gluing area advantageously concentricly flows into the transport pipe, whereby the gap is everywhere the same width. In this way 60 it is ensured that the mixture of glued shredding products and transport air leaving the sizing area towards the transport pipe is uniformly surrounded on all sides by the additional air flow.

Advantageously the section of the pipe in the transport direction is narrowed. By narrowing the section of the pipe before the gluing zone in the transport direction, the speed of the mixture that runs through crushing products and transport air increases.

Preferably, the turbulence valve, of which there is at least one, can be adjusted by means of an electric motor. In this way the rotation length of the rotating flow can be freely adjusted.

With such an installation a procedure can be carried out in which the mixing of the transport air flow with crushing products, by providing the adhesive, is in a turbulent or turning movement around the transport direction and the mixture, after the contribution of the adhesive, it is wrapped by an air flow parallel to the direction of transport.

In the gluing zone, where the adhesive is added by mixing the adhesive to the mixture of transport air and crushing products, a rotating laminar air flow or a turbulent air flow reigns in the described procedure. By means of both kinds of flow, the glued crushing products are prevented from adhering to the walls of the tube and soiling them. In particular, in a rotating laminar flow, the rotation length can be freely adjusted, that is, the section in the direction of transport that the air needs to make a complete turn in the direction of rotation. The material flow of the crushing products is then conducted by its own inertia to the outer wall of the tube of the gluing zone and thus safely avoids deposits and / or eliminates existing adhesions. The same effect has a turbulent air flow, which also prevents glued crushing products from being suspended in the inner wall of the tube.

Once the mixture of glued shredding products and transport air has left the glue zone 20, it is enveloped by another air flow parallel to the transport direction. This ensures that even after leaving the gluing area, the glued crushing products cannot adhere to the inner wall of a transport tube. When the mixture is enveloped by another air stream, contact between the glued shredding products and the inner wall of the tube is largely avoided. 25

Advantageously, the crushing products are in the form of fibers or chips.

In fiber-shaped crushing products, the residual moisture to which the crushing products are dried in step a) of the process is preferably 4 to 6% referred to atro wood, that is, absolute drying. In chip-shaped crushing products, residual moisture is advantageously 2 to 4% referred to atro wood. The turbulent movement of the mixture of crushing products and transport air in the gluing zone is advantageously achieved by a high transport speed of the mixture of 25 to 100 m / s. In addition, this high speed prevents even more adhesion of grinding products already glued to the inner wall in the gluing area. 35

Advantageously, turbulent flow is achieved additionally or alternatively at high speed by increasing the pressure. This also results in less adhesion of crushing products already glued to the inside wall of a tube.

 40

The other air flow that surrounds the mixture of glued crushing products and transport air after leaving the sizing area, has an annular shape and is laminar. In this way it is ensured that the glued crushing products that are in the transport air flow do not adhere to the inner wall of the transport tube, since they barely make contact with this inner wall. Four. Five

Especially advantageously, the other air flow has a temperature higher than the temperature of the mixture.

An exemplary embodiment of the invention will be described in more detail with the help of a drawing. 50 shown in

Figure 1 - a schematic partial representation of an example of the execution of an installation

 corresponding to the invention and

 55

Figure 2 - An enlarged detail of Figure 1.

Figure 1 shows a part of an installation corresponding to the invention, which is used to dry the crushing products. The crushing products to be glued are first dried in a dryer 1 and then conducted by a lobular pump 2 to a pipe 5. The pipeline 5 60 conducts the crushing products to be glued to the gluing equipment. The crushed products already glued are then conducted through the transport pipe 25 to a cyclone separator-classifier 3 and then through another lobe pump 2 to a classifier 4.

The crushing products that are introduced through the lobular pump 2 from the dryer 1 in the pipeline 5, are transported by an air flow through a fan 6 to the cyclone separator-classifier 3. In this process the themselves by means of a tongue 8 in the air flow. In the exemplary embodiment shown in Figure 1, a turbulence valve 7 is provided in the pipe 5

With adjustment device, to be able to rotate the mixture of transport air and crushing products. Through a uniform cone 14, the flow of crushing products in the pipe 5 is accelerated and taken to a gluing zone 12.

In front of the cone 14 only crushed products without glue are found in the pipe 5. To avoid adhesions to the pipe wall safely here, an air velocity of 20 to 25 m / s is necessary.

In the gluing zone 12 the speed of the mixing of transport air and crushing products is clearly increased, as the section is clearly smaller in the gluing zone 12. In the present example, the setpoint speed in the gluing zone 12 It is 100 m / s. The necessary length for the gluing zone 12 is a function of the desired residence time of the crushing products in the gluing zone 12. It has been found that a length of the gluing zone 12 is advantageous from 3 to 8 times the diameter of the tube.

 fifteen

In the gluing zone 12 there are inlet conduits of the tail 11, through which the adhesive or adhesive is added by mixing to the crushing products that fly through. This addition is done, for example, by nozzle spraying. Advantageously, they are unit nozzles, since they can operate without additional air, in particular pressurized air. At the end of the gluing zone 12, the additional air flow is introduced through a gap 9. This air flow is carried out as annular air, which is advantageous for the entire transport system, since the loss of temperature in the crushing products is avoided.

Advantageously, the additional air flow or the annular air is taken from the cyclone separator-classifier 3 by means of an annular air fan 15 and is returned via an annular air pipe 16 to the preceding process. In this regard there is the possibility of heating this annular air by means of a heat exchanger 10 and driving it to the fan 6. A part of the additional air flow is cooled by another heat exchanger 10 and is conducted back, as an additional air flow, to through the annular interstitium 9.

 30

In particular, the different density of the air at different temperatures has an advantage here on the intensity of the separating characteristic of the additional air flow. The amount of additional air flow in the various partial flows can be regulated by means of adjustment valves 17.

For the spraying of the glue in the gluing zone 12 by means of the tail inlet conduit 11 35 both the liquid pressure and the shape of the nozzle are used as well as the shear stress drops due to turbulent flows. In the exemplary embodiment shown in Figure 1, the gluing zone at the center of the transport pipe 25 ends, where the flow of transport air and glued crushing products is enveloped by the additional air flow.

 40

Figure 2 shows the gluing equipment itself in an enlarged representation. It can be clearly seen that the pipe 5 entering from the left is narrowed by the cone 14 towards the gluing zone 12. In the gluing zone 12 is the inlet conduit of the glue 11, whereby the glue or the adhesive It is added by mixing to the crushing products that cross flying. The gluing zone 12 ends at the center of the transport pipe 25, in which the flow of transport air with the crushing products contained therein is surrounded by the additional air flow. The additional air flow is introduced through annular interstices 9 from a pressure chamber 13 to the transport pipe 25.

Reference List

1 dryer

2 lobular pump

3 cyclone separator-classifier 5

4 classifier

5 pipe

6 fan

7 turbulence valve

8 tab 10

9 ring interstitium

10 heat exchanger

11 driving tail entrance

12 glue zone

13 pressure chamber 15

14 cone

15 annular air fan

16 annular air pipe

17 adjustment valve

18 transport pipe 20

Claims (3)

1. Installation to perform a procedure for manufacturing wood-derived materials from crushing products containing lignocellulose with a dryer (1), a sizing equipment associated with the dryer (1), which configures a gluing area (12) cylindrically shaped with a cross section 5 and which is connected to the dryer (1) through a pipe (5), and a transport pipe (25) connected to the gluing area (12), presenting the transport pipe (25) a section larger than the glue zone (12) with a cylindrical shape and a gap (9) between the end of the glue zone (12) and the transport pipe (25), through which can be introduced an additional air flow in the transport pipe (25), 10 characterized in that the annular gap (9) is configured such that a laminar air flow is configured on an inner wall of the transport pipe (25) and that at least one turbulence valve (7) is located in the pipe (5). , to rotate a flow of air flowing through the pipe (5).  fifteen 2. Installation according to claim 1, characterized in that the section of the pipe (5) narrows in the direction of transport. 3. Installation according to claim 1 or 2, characterized in that the turbulence valve (7), of which there is at least one, can be adjusted 20 by an electric motor.