EP3930926A1

EP3930926A1 - Screening device, in particular for use in a system for producing material panels

Info

Publication number: EP3930926A1
Application number: EP20712837.2A
Authority: EP
Inventors: Dieter GEUGIS; Roland Schweizer; Ari MÄNNIKKO
Original assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Current assignee: Dieffenbacher GmbH Maschinen und Anlagenbau
Priority date: 2019-02-28
Filing date: 2020-02-28
Publication date: 2022-01-05
Anticipated expiration: 2040-02-28
Also published as: EP3930926B1; CN113710380B; WO2020174099A1; CN113710380A

Abstract

The invention relates to a screening device for use in a system for producing material panels, which screening device comprises a support frame (1) and a screening unit (2), which is suspended on the support frame (1) by means of suspension elements (3) in such a way that the screening unit (2) can move on a circular trajectory. The screening unit (2) has at least one screening module (4) and a drive apparatus (8), which moves the screening unit (4) in a circular motion on the circular trajectory. Furthermore, at least one electric-motor-operating and/or hydraulically operating adjusting device (20) is provided, which is designed to adjust the suspension of the screening unit (2) on the support frame (1) by means of the suspension elements (3) in order to adjust an angle of inclination of the screening unit (2). The angle of inclination can be adjusted in particular during the operation of the screening device.

Description

Siebvorrichtunq, in particular for use in a plant for the production of material panels

The present invention relates to a screening device, preferably of the circularly moving type, particularly preferably for use in a plant for the production of material panels, according to claim 1.

In the manufacture of wood-based panels, as a rule

Sieving devices of the circular moving type used to

After machining or defibering and drying, wood-based raw material is divided into fractions of different sizes. The so sifted in

Particles separated by size fractions can then be

Manufacturing process of material panels made of wood can be used by, for example, scattered in a manner known per se to form a wood material mat and the mat is pressed in a continuous press to form a panel strand. The string of plates can then become individual

Wood-based panels are isolated.

Such circular or reciprocating screening devices are typically large steel structures in which one is welded

Steel construction forms a support frame of the device, on which the actual sieve unit is suspended via suspension elements, which are usually designed as articulated rods. The sieve unit can thus move on a substantially circular path in the horizontal plane. It is preferably not a sieve vibrating back and forth, but a sieve with circular motion, in which a constant centripetal acceleration, which rotates around a substantially vertical axis, brings the material to be sieved onto and through the sieve levels. A typical diameter of an orbit is 40-80 mm and the

Circulating speed is typically 150-200 rpm.

The sieving is usually carried out by means of 2 to 4 sieve stages, which are formed from sieve grids that are slightly inclined with respect to the horizontal plane. The angle of inclination is generally 5-10 °. The material to be screened flows in the direction of the slope. The sieve grids are accessible via side doors or hatches so that they can be removed and replaced.

The screening devices are typically large steel structures where the width of the support frame is more than 3 m and the length of the

Support frame is generally between 5 and 10 m. In addition, there are usually rigid structures with solid

Inclination angle. A change in the angle of inclination is such

Sieving devices are therefore not possible or only with difficulty.

As has been shown in laboratory tests by the applicant, the

The angle of inclination has a major influence on the volume flow of the material that is passed through and screened by the sieve unit. In particular, even relatively small differences in the angle of inclination show clear

Differences in the maximum retention time of particles on the sieve. On the basis of these attempts it was recognized that - also and

in particular for different material to be screened that changes during operation - by adjusting the angle of inclination, an optimization towards a higher dust or fine material screening (for a given screen length) can be achieved, or that for a given, required level of

Fine material screening the length of the screening section can be chosen to be shorter, which means that the screening device is smaller and smaller for a given pass so that can be dimensioned more cost-effectively, or that for a

Sieve device of a given size a higher maximum throughput is made possible.

The document WO 2015/200382 A1 describes a circularly moving sieve device for use in the pharmaceutical, medical, oilfield, food and other industries, in which a drive unit is movably suspended in a support frame. A screen unit is arranged on the drive unit and is supported by means of angle pieces and brackets. The angle pieces and brackets are designed in such a way that they can be connected to one another at different points in order to adjust the inclination of the

Allow sieve unit. The adjustment of the inclination of the sieve unit can be carried out in this way without structural changes and in an easier way. Due to the design of the elbows and

Brackets predetermined limited number in different positions, however, only a limited number of fixed predetermined,

different angles of inclination can be set. Also it is for

Adjustment necessary, the connection between contra-angles and

To solve brackets, which can only be done when the screening device is at a standstill and requires additional work equipment, such as a crane or the like to hold the screening unit.

It is therefore an object of the present invention to provide a screening device of the circularly moving type for use in a plant for wood-based panel production, which allows a simple and stepless adjustment of the angle of inclination, especially during operation of the screening device. These and other objects of the invention are achieved with one

Sieving device as specified in claim 1. Preferred embodiments are set out in the dependent claims.

In one aspect, a screening device for use in a

Wood-based panel manufacturing plant specified, comprising a

Support frame and a sieve unit, the sieve unit over

Suspension elements is suspended on the support frame in such a way that the sieve unit can move on a circular trajectory, the sieve unit having at least one sieve module and a drive device, and wherein the drive device is set up to put the sieve unit in a circular movement on the circular trajectory . The screening device further comprises at least one electric motor and / or hydraulic adjusting device which is set up to suspend the screening unit on the support frame by means of the

Adjusting suspension members to adjust an inclination angle of the screen unit; and a control unit for controlling the at least one adjusting device.

With the help of the electric motor and / or hydraulic

Adjusting device (s), a stepless adjustment of the angle of inclination, for example between 4 ° and 12 °, can be made. It is also not necessary for the angle of inclination to be adjusted mechanically

Connections or fastenings are loosened, which facilitates the adjustment of the angle of inclination considerably. It is also not necessary to stop the sieve device in order to adjust the angle of inclination, so that it is now possible to adjust the angle of inclination of the sieve unit while it is running

To adjust the sieving operation of the sieving device.

The at least one adjustment device operated by an electric motor

Ball screw or be designed as a hydraulic linear axis. There can preferably further be provided that the at least one adjusting device further comprises a rotary encoder system and / or a

Having a linear scale system, wherein a position control of the at least one adjusting device based on the measured values of the

Rotary encoder system and / or the linear scale system is executed, and / or wherein the control device determines the actual angle of inclination on the basis of the measured values of the rotary encoder system and / or the linear scale system.

Furthermore, at least one sensor can be provided for determining the volume flow through the screening device, and the control device can further be set up to carry out an automatic angle of inclination adjustment on the basis of the determined volume flow.

In this way, an automatic and optimal angle adjustment of the inclination can be carried out as a function of a changing, actual volume flow and the operation of the screening device can thus be optimized.

The suspension elements are preferably designed as steel cables. It can also be provided that two are designed as steel cables

Suspension elements via pulleys to a common

Adjusting device are guided and operated by this.

The at least one sieve module can have a plurality of sieve grids which are arranged one above the other and have different mesh sizes in order to sieve the wood raw material to be sieved into fractions of different sizes. At least one light barrier can preferably also be provided, which is arranged over a sieve grid running transversely to this, for

Determination of the length of the sieve module over which the sieve grid is covered with material to be sieved, wherein the control unit is preferably set up to automatically adjust the angle of inclination on the basis of the determined Result. In this way, the operation of the screening device can be further optimized.

Instead of the light barrier, other measuring systems or

Measuring devices conceivable, for example optical scanners,

Reflection measurements of the sieve surface, light barriers for the material falling through the sieve, etc.

The screen unit can have two screen modules and a frame module, the frame module being arranged between the screen modules. In particular, the at least one drive device can be arranged in the space between the screen modules. In this way, a very compact design can be achieved.

In the following the invention is made more preferred with the help of some

Embodiments described in more detail with reference to the accompanying drawings:

It shows:

1 shows a view obliquely from above of a screening device according to an embodiment of the invention;

Fig. 2 the frame module of the screening device according to the

Embodiment and the drive devices of the frame module;

3 shows the sieve device according to the embodiment viewed from an outlet-side end, and FIG

Fig. 4 schematically shows an alternative embodiment of a

Adjustment device for angle adjustment.

Fig. 1 shows a sieve device according to an embodiment of the invention. The Sieborrichtung comprises a support frame 1 and a suspended thereon, movable screen unit 2. The suspension is formed by a plurality of suspension elements 3. In Fig. 1 there are four

Suspension elements 3 shown, which in this example are formed by hinged rods.

In this embodiment, the sieve unit 2 comprises two sieve modules 4 and a frame module 5 arranged between them. The frame module 5 preferably functions at the same time as a carrier and fastening for the

Sieve modules 4.

A sieve module 4 comprises one or more sieve chambers, which in

Are substantially stacked and structurally separated from one another, e.g. with a fixed intermediate level, in particular a sieve grid 7. In each of these chambers, which are also referred to as deck, the material to be sieved is sieved into at least two fractions. In the drawings there is shown an embodiment in which the screen is double-decked, i. there are two sieve chambers arranged one above the other in each sieve module 4.

The material to be sieved is fed into the feed funnel according to the arrows 6 and the sieved fractions are removed from the other end of the sieve in a manner known per se, each fraction being discharged onto its own conveyor belt.

The sieve modules 4 comprise sieve grids 7 (FIG. 3). The sieve modules 4 and their sieve grids 7 are inclined at an angle of inclination, which is preferably in the range between 4 ° to 12 °, to the horizontal plane, the material to be screened flowing in the direction of the inclination when the sieve unit 2 is set in a horizontal circular motion becomes.

The circular movement can be done with at least one, in the embodiment according to FIG. 2 with two drive devices 8, which are eccentric in their mass and are located at least for the most part within the frame module 5, the drive devices having rotating shafts 9 which are essentially vertical and which, during operation, set the screen unit 2 in a circular motion on a circular trajectory in the horizontal plane. The eccentric masses or weights 10 of the rotary shafts 9 are located within the frame module 5, which reduces the space requirement and allows the screening device to be designed to be smaller and more space-saving.

3 shows the sieve device viewed from the outlet-side end and in a partially opened illustration.

According to the invention it is provided that the angle of inclination is not fixed, as is customary in the prior art for such screening devices, but provision is made for the angle of inclination to be continuously adjustable. For this purpose, as shown in FIGS. 1 to 3, one or more is or are

Adjusting devices 20 are provided which act on some or all of the

Suspension elements 3 act to raise or lower one end of the sieve unit 2 and / or lower or raise the other end of the sieve unit 2.

As a non-limiting example, Figures 1 to 3 show two

Adjusting devices 20, which at an outlet end of the

Sieve device are attached to the support frame 1. The adjusting devices 20 are each driven by a motor 24

Recirculating ball screw 22 executed, the respectively associated

Suspension element 3 is attached to the spindle nut. If the

Adjusting devices 20 from a control unit (not shown)

can be controlled accordingly, the respectively assigned

Suspension elements 3 are raised or lowered to raise or lower the respective end of the screen unit 2, so as to To adjust the angle of inclination. Thus, in the example of FIGS. 1 and 2, with the two adjustment devices 20 provided at the outlet end of the sieve unit 2, the outlet end of the sieve unit 2 can be raised, and thus the angle of inclination can be reduced or lowered and thus the angle of inclination increased.

The motors 24 are preferably designed as servomotors which are connected to a corresponding servo drive unit, with a further

Sensor system, in particular a rotary encoder system or a

Linear scale system, can be provided that the determination of the

Rotation angle of the motor axis or the linear position of the spindle nut allows. The servomotors can preferably be in one

Position control mode are operated. Under the control of the control unit, it is possible that when adjusting the angle of inclination, the two

Adjusting devices 20 work synchronously so that the sieve unit 2 can be raised equally and evenly on both sides. This is particularly advantageous if the adjustment of the angle of inclination takes place during operation, since in this way no undesired tilting or lateral inclinations of the sieve unit 2 are triggered, which could disrupt operation.

The angle of inclination can also be determined mathematically from the data of the rotary encoder systems or the linear scale systems, so that a predeterminable and reproducible setting of the angle of inclination is possible.

For example, an operator can enter a desired angle of inclination via an input device, whereupon the control unit

corresponding setpoint values are calculated for the adjusting devices 20 and output to the adjusting devices 20. It can be based on the

Actual values detected by sensors are used to carry out a regulation, the control loop being able to be carried out in the control unit or in the servomotor drive unit. Alternatively or in addition, it is also possible to adjust the angle of inclination automatically. For example, one or more sensors can be used to detect the volume flow or the

The flow rate of material to be screened or already screened can be provided, with a corresponding target inclination angle, in particular an optimal target inclination angle, being determined on the basis of the actual flow rate recorded in this way by means of a look-up table or by means of arithmetic formulas, the control device adjusting the actual, Actual inclination angle caused to the target inclination angle. Alternatively, the flow rate can also be based on the flow rate specified in the system, in particular as a setting value

higher-level system control. The automatic adjustment of the angle of inclination can in particular take place in such a way that in this way it is effected that, while setting, the respective

Inclination angle also for different or temporally variable

Throughput quantities each cause the sieve grids 7 of the sieve modules 4 to be covered with material to be sieved, essentially over their entire length. Alternatively or in addition, it is also possible to provide appropriate sensors in the sieve modules 4, for example light barriers, which are arranged over the sieve grids 7 and running across them, with which it can be detected how far the sieve grids 7 are still covered with material to be sieved are.

While with reference to FIGS. 1 to 3, a possible embodiment

has been described, this description is not restrictive and many modifications and additions are possible.

For example, if the screen unit is suspended at 4 points, as shown in FIGS. 1 to 3, four adjustment devices 20 are provided which interact with the four suspension elements 3, to adjust the angle of inclination by simultaneously raising one end and lowering the other end of the sieve unit 2. It is also possible to provide a suspension at more than four suspension points, for example at six suspension points, with

correspondingly four or six suspension elements 3 are each assigned to corresponding adjustment devices 20.

In addition, the adjusting device 20 is not limited to a configuration as a ball screw 22 driven by an electric motor. A design as a hydraulically operated linear axis in FIG

To be considered. The use of hydraulics in the

Adjusting devices 20 offers the advantage that all hydraulic cylinders can be subjected to the same pressure, which ensures that all suspension elements 3 are loaded with essentially the same weight.

Further configurations of the adjusting devices will be readily apparent to the person skilled in the art.

It is also possible that the suspension elements 3 are not designed as hinged rods, but rather as steel cables. In this case it is

possible, for example, to design the adjusting devices 20 as winches driven by an electric motor, which as steel cables

(Suspension elements 3) wind or unwind so as to the

To adjust the angle of inclination.

It can also be provided that, as shown in FIG. 4, the steel cables are deflected by means of deflection pulleys 30. This makes it possible, for example, to bring the steel cables together from two sides of the screen unit 2 in order to attach them to an adjusting device 20 so that the two steel cables, and thus the two sides of the screen unit 2, when the angle of inclination is adjusted are each adjusted jointly and synchronously by the common adjusting device 20.

While it is preferred to provide the adjustment devices 20, as shown in FIGS. 1 to 3, fixed on the support frame 1, those skilled in the art will understand that fixing the adjustment devices 20 on the

Sieve unit 2 is also conceivable.

It is also conceivable instead of or in addition to the in the

Adjusting devices 20 provided rotary encoder systems or

Linear scale systems provide other or further sensor systems with the aid of which the actual inclination angle of the sieve unit 2 can be detected.

Although an embodiment is described above which comprises a frame module 5 and two screen modules 4, this is not restrictive, and it is also possible to use more than two screen modules 4 in combination with one or more frame modules 5.

Support frame

Sieve unit

Sieve module suspension element

Frame module

Material supply

Sieve grid

Drive device rotary axis

Weights

Explosion hatch

Flame extinguishing device adjusting device ball screw motor

Pulley

Claims

1. Sieve device, in particular for use in a plant for the production of material panels, comprising a support frame (1) and a sieve unit (2), the sieve unit (2) over

Suspension elements (3) are suspended from the support frame (1) in such a way that the sieve unit (2) can preferably move on a circular trajectory, the sieve unit (2) having at least one sieve module (4) and a drive device (8), and wherein the drive device (8) is set up to set the sieve unit (4) in a preferably circular movement on the circular trajectory,

characterized in that

the screening device further comprises:

at least one electric motor and / or hydraulic adjusting device (20) is provided which is set up that

Adjusting the suspension of the sieve unit (2) on the support frame (1) by means of the suspension elements (3) in order to adjust an angle of inclination of the sieve unit (2); and

a control unit for controlling the at least one

Adjusting device (20).

2. Sieving device according to claim 1, characterized in that the at least one adjusting device (20) is set up, the Adjust the inclination angle of the sieve unit (2) while the sieve device is in operation.

3. Sieving device according to one of the preceding claims, characterized in that the angle of inclination is adjustable between 4 ° and 12 °.

4. Sieving device according to one of the preceding claims, characterized in that the at least one adjusting device (20) is designed as an electromotive-operated ball screw (22) or as a hydraulic linear axis.

5. Sieve device according to claim 4, characterized in that the at least one adjusting device (20) further comprises a rotary encoder system and / or a linear scale system, wherein further a

Position control of the at least one adjusting device (20) based on the measured values of the rotary encoder system and / or the

Linear scale system is carried out, and / or

the control device determining the actual angle of inclination on the basis of the measured values of the rotary encoder system and / or the linear scale system.

6. Sieving device according to claim 5, characterized in that at least one sensor is further provided for determining the volume flow through the sieving device, the control device being further configured to automatically adjust the angle of inclination on the basis of the determined volume flow.

7. Sieving device according to one of the preceding claims, characterized in that the suspension elements (3) are designed as steel cables.

8. Sieving device according to claim 7, characterized in that two suspension elements (3) designed as steel cables are over

Deflection rollers (30) are guided to a common adjusting device (20) and actuated by this.

9. Sieve device according to one of the preceding claims, characterized in that the at least one sieve module (4) has several sieve grids (7) which are arranged one above the other and have different mesh sizes in order to be sieved

Sifting wood raw material in fractions of different sizes.

10. Sieving device according to one of the preceding claims, characterized in that at least one means for determining the occupancy of the sieve grid (7) of a sieve module with material to be sieved is arranged, the control unit preferably being set up to carry out an automatic angle of inclination adjustment based on the determined result .

11. Sieve device according to one of the preceding claims, characterized in that the means for determining the occupancy is a light barrier, preferably transversely to the sieve grid, an optical sensor, a camera system, means for determining the weight on a sieve grid (7), systems for detection in which areas material falls through the sieve grid or the like is arranged.

12. Sieve device according to one of the preceding claims, characterized in that the sieve unit (2) has two sieve modules (4) and a frame module (5), the frame module (5) being arranged between the sieve modules (4).

13. Screen module according to one of the preceding claims, characterized in that the at least one drive device (8) is arranged in the space between the screen modules (4).