FI3902637T3

FI3902637T3 - Device and method for setting and controlling at least one oscillation mode by means of the plurality of unbalance exciter units on a screening device

Info

Publication number: FI3902637T3
Application number: FIEP20715796.7T
Authority: FI
Inventors: Guido Leuschen; Florian Malcher
Original assignee: Smidth As F L
Priority date: 2019-04-04
Filing date: 2020-03-25
Publication date: 2023-11-03
Also published as: RS64774B1; EP3902637B1; DK3902637T3; DE102019204845B3; WO2020200943A1; EP3902637A1

Claims

1 20715796.7 DEVICE AND METHOD FOR SETTING AND CONTROLLING AT LEAST ONE OSCILLATION MODE BY MEANS OF THE PLURALITY OF UNBALANCE EXCITER UNITS ON A SCREENING DEVICE The invention relates to a device and a method for setting and controlling at least one oscillation mode by means of the multiplicity of unbalance exciter units on a screening device.

In particular, the invention relates to a device and a method according to the preamble of the respective independent or subordinate claim.

Methods and devices for adjusting the oscillation behavior of a oscillating conveyor with electric motor-driven, counter-rotating unbalance drives are known.

For example, it is known to adjust the position of the unbalanced masses relative to one another.

The desired oscillation angle can be changed during operation, and/or a predefinable oscillation angle can be maintained regardless of the material being conveyed.

In contrast, measures for a stationary arrangement of the unbalance drives are also known.

In particular, the publication DE 10 2017 218 371 B3 describes a screening system with oscillation systems arranged in oscillation nodes, in which screening system the phase offset of unbalance drives can be controlled.

With regard to screens that are as large as possible, as well as with regard to minimizing the mechanical loads on the screen structure and a structural design of the entire system that is as slim and material-saving as possible, a more targeted, precise influence on the oscillation behavior is of interest, especially for the purpose of setting different operating states of the vibrating screen.

From EP 2 910 312 Al a method for setting and controlling at least one oscillation mode of a screening device according to the preamble of claim 1, and an oscillation arrangement for a screening device are known.

A method for controlling the oscillation of a vibrating device is known from WO 2014/066893 Al.

A screening system with at least two oscillation systems is known from DE 10 2017 218 371 B3. A screening device is known from US 2008/0237095 A1. A device for processing mineral material is known from US 2015/0122921 A1. The object of the invention is to provide a method with the features described above, with which the functional spectrum of oscillating screens, in particular of

2 20715796.7 oscillating conveyors, can be expanded in a simple manner, especially with an advantageous structural design, in particular with the greatest possible variability.

This object is achieved by a method according to claim 1. Advantageous embodiments are set out in the dependent claims.

Also disclosed is a screening device set up for screening material to be screened, in particular for screening mineral rock, the screening device having a multiplicity of unbalance exciter units which act vibrationally at a plurality of coupling points on the screening device, wherein the screening device has an actuating and controlling device and being set up for adjustment and controlling at least one oscillation mode by means of the multiplicity of unbalance exciter units; wherein the unbalance exciter units are grouped in several clusters of at least two unbalance exciter units, wherein each cluster is coupled to the screening device in terms of oscillation in one of the coupling points, wherein the screening device is set up by means of the actuating and controlling device to actuate and control the respective cluster for acting on the screening device by a cluster oscillation in the respective coupling point per cluster, wherein at least two of the clusters are actuatable and controllable depending on one another with regard to the oscillation generated, in particular at least four clusters (i.e. at least eight unbalance exciter units).

This also enables effective influence when there is great variability.

On the one hand, controlling in subsets according to the number of clusters can be carried out in a comparatively simple manner depending on the number of pathogens per cluster, on the other hand, a large amount of variability can be provided by the plurality of clusters.

Each cluster can generate a cluster oscillation through a plurality of exciter units, which can be coupled into the mechanical structure, particularly in the area of an oscillation node.

The excitation can take place at several coupling points in coordination with one another and can be optimized for a respective operating state.

Last but not least, this enables an optimized, slim design.

Safety factors can be reduced.

For example, a change from linear to elliptical or circular oscillation can be easily set.

Particularly with regard to the screening function, screening can be carried out in a particularly selective manner, e.g. individualized with regard to a large amount of material and/or a large amount of fines, or with regard to a small amount of material and/or a small amount of fines.

Energy benefits can also be realized, particularly due to high efficiency in terms of excitation.

Mechanical transmission losses can be minimized.

3 20715796.7

It has been shown that thanks to the electronic or control coupling of at least two exciter units per cluster and thanks to the coupling of the clusters to one another, the desired oscillation shapes can be predefined and controlled in a very variable and flexible manner.

In contrast, with previous arrangements usually only a single specific oscillation pattern can be generated.

According to the invention, a freely modulated oscillation shape can be implemented in a flexible manner, in particular also scalable and customizable with the same control concept for different devices.

In particular, it has been shown that by superposing individual pairs of unbalance exciter units, the oscillation shape of the screening structure can be modulated almost freely in amplitude and shape.

In particular, different oscillation behavior can be generated when material is fed in {acting upon it) and when it is released (individual controllability, in particular depending on the operating situation/operating state).

Mechanical components or mechanical interfaces can be designed in particular as described in the publication DE 10 2017 218 371 B3. In particular, the clusters can be arranged in the area of the oscillation nodes according to the arrangement described in this publication.

According to the invention, a cluster oscillation is to be understood as a oscillation generated together by a plurality of unbalance exciter units (resulting oscillation from superimposed individual oscillations of the cluster). According to the invention, the cluster oscillation can be introduced into the mechanical structure of the screening device at a (single) predefinable coupling point.

In other words: a oscillation impact point can be defined for each cluster.

An unbalance exciter unit is, for example, a unit with a controlled rotatable mass,

in particular an asynchronous motor, which is set up to generate a predefinable oscillation pattern.

According to one exemplary embodiment, the unbalance exciter units are vibrationally coupled to the screening device in at least two coupling points on opposite sides of a screening deck, in particular in an arrangement in a cluster of two, three or four unbalance exciter units per coupling point.

In this way, the desired variability can be ensured even with a simple structural design.

In particular, a coupling for optionally two, three or four or even more exciters per cluster or per coupling point can be arranged on side walls, in particular in the area of an oscillation node.

4 20715796.7

According to one exemplary embodiment, the unbalance exciter units are arranged in clusters in pairs in a twin arrangement and/or in a triplet arrangement (clusters with three unbalance exciter units each) and/or in a quadruple arrangement {clusters with four unbalance exciter units each), in particular on a side wall of the screening device.

This can also make it easier to initiate the cluster oscillation at a predefined coupling point.

The unbalance exciter units can be arranged in clusters in pairs in a twin arrangement, with the paired unbalance exciter units being arranged horizontally next to one another or vertically one above the other.

The unbalance exciter units can be arranged in clusters in a triple arrangement, wherein the three unbalance exciter units are arranged in a triangular arrangement, in particular according to an equilateral triangle, in particular with the tip of the triangle pointing downwards.

The unbalance exciter units can be arranged in clusters in a quadruple arrangement, wherein the four unbalance exciter units are arranged in a parallelogram arrangement, in particular with an offset in the horizontal direction.

The unbalance exciter units can be arranged in clusters of two or three unbalance exciter units or multiples thereof.

The clusters can each be individually controllable, in particular in a way that is dependent on one another in terms of control technology.

According to one exemplary embodiment, the respective unbalance exciter unit is defined or actuated/controllable by at least one of the following parameters: unbalance mass, exciter speed, exciter direction (in particular direction of rotation), phase offset to at least one of the further unbalance exciter units.

Last but not least, the ability to combine these parameters provides high variability and targeted influence on control effects.

According to one exemplary embodiment, the unbalance exciter units are each designed as asynchronous motors or have at least one asynchronous motor.

According to one exemplary embodiment, the screening device has at least four clusters, each with at least two unbalance exciter units.

According to one exemplary embodiment, the screening device is set up to move through a resonance range without force, in particular when starting up or switching off.

According to one exemplary embodiment, the screening device has:

- a screening box comprising two outer side walls, wherein at least two oscillation systems for oscillation excitation are arranged on each of the two side walls,

20715796.7 and wherein the two side walls each have at least two oscillation nodes according to a bending mode, - at least two trusses that connect the two side walls together, - at least one screening deck that rests on at least two traverses.

In this way, a 5 structural design that is advantageous for many different materials can be provided, in particular for a conveying function of the screen.

The aforementioned object is achieved according to the invention by a method for setting and controlling at least one oscillation mode of a screening device, wherein the respective oscillation mode is controlled by means of a multiplicity of unbalance exciter units, wherein each of the unbalance exciter units is actuated and controlled individually with regard to a multiplicity of parameters, characterized in that the unbalance exciter units in an arrangement in several clusters of in each case at least two unbalance exciter units are actuated and controlled for impinging the screening device by means of a cluster oscillation in a respective coupling point per cluster, wherein a cluster oscillation generated by a plurality of unbalance exciter units, wherein at least two of the clusters are actuated and controlled depending on one another with regard to the generated oscillation, in particular at least four clusters (i.e. at least eight unbalance exciter units). This provides previously mentioned advantages.

The control can also be simplified by giving a respective cluster one of several optional vibrational specifications, whereby a desired absolute oscillation effect is set in combination with the other clusters.

For example, with four clusters and three to five predefined exciter states, a variety of different operating states can be easily imposed.

According to one embodiment, the screening device for each cluster is either set/regulated to a linear oscillation or an elliptical oscillation or a circular oscillation.

The free variability with regard to the type of oscillation can be considered a great advantage with regard to multifunctional use of the device.

The screening device can be adjusted to a linear oscillation for each cluster by at least controlling or varying the excitation direction.

The screening device can be adjusted to an elliptical oscillation for each cluster by controlling at least two excitation directions depending on one another.

The screening device can be adjusted to a circular oscillation for each cluster by operating the unbalance exciter units with the same excitation direction, in particular with a 180° phase offset.

For each cluster, the screening device can

6 20715796.7 be adjusted from a linear oscillation to a circular oscillation or elliptical oscillation, or vice versa, by changing at least one of several excitation directions and keeping at least one excitation direction constant.

In an elliptical oscillation, the oscillating body oscillates in a preferred oscillation direction, similar to a linear oscillation, but this oscillation is superimposed by an oscillation transverse to the main oscillation direction with an amplitude between O (linear oscillation) and the amplitude of the main oscillation direction {circular oscillation). An operating mode with elliptical oscillation makes it possible, in particular, to combine the advantages of an aligned throw that can be achieved with linear oscillators with a comparatively low risk of clogging (lower than with circular oscillators).

According to one embodiment, at least one of the following parameters is controlled per cluster, in particular individually for each unbalance exciter unit: excitation force, excitation speed, excitation direction (in particular direction of rotation), phase offset to at least one of the unbalance exciter units, in particular in the case of combined control of at least the parameters of excitation speed, excitation direction and phase offset.

The phase offset can be controlled in particular by varying the speed over time.

According to one embodiment, the at least one oscillation mode of the screening device is set by controlling the oscillation mode of all clusters in a harmonized manner by combined control of at least the parameters excitation speed, excitation direction and phase offset per cluster, in particular with reference to at least one master curve per cluster.

In particular, individual master curves with virtual axes can be predetermined for each exciter unit, in particular each coupled to form an entire master curve.

Deviations between the real (current) axis and the virtual axis can be defined as a control deviation for specifying control countermeasures.

It has been shown that control individually for each exciter unit, without reference to a single reference exciter unit with a leading function, can lead to a robust control that is largely independent of disturbances.

When controlling, for example, rotary angle encoders {incremental encoders, absolute encoders, resolvers) can be used to record current relative positions.

Such sensors can be in communication with frequency converters.

According to the invention, exciter position feedback occurs in that the individual exciters communicate directly with the actuating/controlling unit.

For example, a pulse can be transmitted to calculate a

7 20715796.7 relative position.

For example, an offset for a speed controller can be determined to control phase offsets.

When measuring the motor current, the influence of gravity on the power requirement of the unbalance motors can be taken into account.

The predetermined speed can, for example, be variable over time according to a ramp function.

According to the invention, at least one master curve that is generated/ predetermined purely mathematically without measured values defines a virtual measurement curve, with respect to which the control is carried out at least for each cluster or within the respective cluster individually for each unbalance exciter unit.

This also makes it possible to decouple any disruptive influences, and the control can be carried out in a particularly robust manner, even if a large degree of variability is desired.

A master curve can provide a comparatively exact reference value for the respective control parameter.

In particular, a movement curve based purely on mathematical aspects is generated, with respect to which the control can take place in a comparatively precise manner.

For example, an angular range from 0 to 360° or O to 2xPi (circle number) is plotted over time, and this is repeated continuously.

The time of a revolution is determined by the speed; for example, at 750 revolutions per minute, the rotation time is 80ms.

This master curve has, e.g. the shape of a sawtooth.

The master curve can be predefined without artifacts or measurement tolerances.

In contrast, in previously known master/slave systems, in which the position of a master motor is measured and the slaves are adapted to it, a disturbance caused by measurement errors and influences of gravity must be tolerated.

Optionally, multiple master curves can be defined for a variety of parameters.

The target curves (target variables for the control parameters) for the respective clusters or unbalance exciter units can be correlated to the master curves.

Individual phase offsets, directions of rotation, and/or individual speeds compared to the master curve can represent the virtual axes of the unbalance exciter units.

The unbalance exciter units are controlled in particular with regard to these virtual axes.

It can also be predefined in which way the respective target curve/target curve should be correlated with the main master curve, in particular with regard to speed, phase offset and/or direction of rotation.

The respective parameter can remain constant or be set variably over one revolution, for example to compensate for the effects of gravity.

8 20715796.7 For example, a phase offset, a direction of rotation and/or a speed is/are each measured and controlled relative to the master curve. Any disturbances can be advantageously minimized. According to one embodiment, the unbalance exciter units are actuated and controlled in clusters of two or three or four unbalance exciter units. The unbalance exciter units can be actuated and controlled in clusters of at least three unbalance exciter units, wherein at least one of the unbalance exciter units of the cluster is operated in a time-controlled manner in different or shorter time windows than the other unbalance exciter units of the cluster. According to one embodiment, for an operating state for switching off or decaying the screening device, the unbalance exciter units are controlled in such a way that the end position (rest position) is correlated with the zero position of the respective unbalance exciter unit assumed due to gravitational forces, in particular with the lowest center of mass of the respective unbalance exciter unit. According to one embodiment, for an operating state for homogenizing the loading of the screening device, the unbalance exciter units are controlled in such a way that the phases of the unbalance exciter units are harmonized with one another for setting an exciter force uniformity over the extension of a screening deck of the screening device, in particular by means of a respective cluster comprising at least three unbalance exciter units. According to one embodiment, a controlled superposition of oscillations of the respective clusters takes place, in particular by controlling at least the excitation speed and the phase offset. The aforementioned object is according to the invention, according to claim 6, also solved by a computer program product set up to carry out a method according to the invention when the method is carried out on a computer. Further features and advantages of the invention result from the description of at least one exemplary embodiment based on drawings, as well as from the drawings themselves. Thereby

Fig. 1 shows a perspective view of a screening device with a actuating and controlling device according to an exemplary embodiment;

9 20715796.7

Fig. 2A, 2B, 2C, 2D show each in a schematic representation in a side view of exemplary arrangements for unbalance exciter units, each in a cluster according to an exemplary embodiment;

Fig. 3 show a schematic representation in side view of a general schematic diagram regarding actuating and controlling of a cluster according to an exemplary embodiment;

Fig. 4A, 4B, 4C, 4D show each in a schematic representation in a side view of exemplary control situations or operating states for unbalance exciter units, each in a cluster according to an exemplary embodiment. Reference numerals that are not explicitly described in relation to a single figure refer to the other figures. For ease of understanding, the figures are described together in sections with reference to all reference numerals. Details or special features shown in the respective figures are described individually.

Fig. 1 shows side walls 31, 32 of a screening box 2 of a screening device 1 set up for screening, for example, mineral rock. Oscillation systems 4 for stimulating oscillations are arranged on the side walls 31, 32 shown in each case. The side walls 31, 32 are in particular designed to be mirror-symmetrical. In particular, the two side walls 31, 32 are arranged mirror-symmetrically to one another to a vertical mirror plane which extends along a conveying direction x. In particular, the side walls 31, 32 are arranged parallel to one another, The side walls 31, 32 include or support traverses 5, which connect the two side walls 31, 32 to one another and support them on one another. A screening deck 6 is supported on some of the trusses 5. In the present case, all trusses 5 are designed identically, namely as tubes with a hollow profile. Screened mineral rock falls vertically downwards through recesses in the screening deck 6. Mineral rock that is larger than the recesses in the screen deck 6 can, depending on the desired operating state, be moved via the screening deck 6 along a conveying direction x by stimulating the oscillation systems 4. According to the invention, the screening deck 6 is excited by cluster oscillations, which are each coupled into the side walls by one of several clusters. Each oscillation system 4 here includes, for example, two unbalance exciter units 41, which are arranged in a cluster 40 in the area of a oscillation node. The cluster can also include more than two unbalance exciter units, for example three or four unbalance

10 20715796.7 exciter units, in particular in a triangular arrangement, in particular according to an equilateral triangle, or in a quadruple arrangement, in particular in a parallelogram arrangement with an offset in the horizontal direction (Fig. 2ff.). The oscillation systems 4 can each be arranged on the respective side wall 31, 32 in such a way that each oscillation system 4 or each cluster 40 overlaps a oscillation node of the respective side wall 31, 32 or is arranged in the area of the respective oscillation node of a bending mode of the respective side wall 31, 32. In particular, the unbalance exciter units 41 of each oscillation system 4 are arranged such that each oscillation node is positioned between the unbalance exciter units, in particular in the middle. Each unbalance exciter unit can in particular have at least one unbalance mass. In particular, the screening device 1 has a actuating and controlling device 7, which is connected to the unbalance exciter units in order to set at least one oscillation parameter for a respective cluster. In the example shown, the screening device has four clusters 40, each of which can be coupled to the corresponding side wall at a coupling point P. Optionally, the screening device comprises more than four clusters, for example six or eight clusters.

Fig. 2A shows a cluster 40 with a twin arrangement of two unbalance exciter units 41 at least approximately horizontally next to one another.

Fig. 2B shows a cluster 40 with a twin arrangement of two unbalance exciter units 41 at least approximately vertically one above the other.

Fig. 2C shows a cluster 40 with a triplet arrangement of three unbalance exciter units 41 according to a triangle geometry, in particular according to an eguilateral triangle, with the tip of the triangle pointing downwards. The use of at least three unbalance exciter units enables, for example, a temporary force variation, in particular by means of phase adjustment. One application arises, for example, when the mass of the feed material is unevenly distributed (inhomogeneous screen loading). Then, in particular, the overloaded section of the screen can be subjected to greater force, with the effect that the feed material can be distributed more homogeneously on the screen.

Fig. 2D shows a cluster 40 with a guadruple arrangement of four unbalance exciter units 41 according to a parallelogram geometry with an offset in the horizontal direction, in particular with the lower unbalance exciter units offset to the right.

11 20715796.7 The unbalance exciter units shown in Figures 2 can each be defined by at least the following parameters or parameters: unbalance, (rotational) speed, direction of rotation, phase offset (in particular phase offset to a predefinable master curve). A coupling point P is shown in each of Figures 2. The coupling point P can be a coupling point of the respective cluster 40 to the corresponding side wall 31, 32 that is at least geometrically and optionally also mechanically (device-technically, structurally) defined.

Fig. 3 shows in principle a control state for dissipating forces, with instantaneous force vectors that are precisely aligned with one another using the example of a cluster with two unbalance exciter units. In this state, for example, a system can be started up without power and without damaging the structure, in particular to avoid resonance oscillations. A (momentary) force vector F of the first unbalance exciter unit points (especially at this illustrated excitation time) in the opposite direction as the force vector F of the second unbalance exciter unit; the two force vectors F point towards one another. As in the following figures, the direction of rotation of the respective unbalance exciter unit is indicated by a semicircular arrow above the respective unbalance exciter unit. The unbalance exciter units rotate in opposite directions to each other.

Fig. 4A shows a cluster in which a (current) force vector F of the first unbalance exciter unit (specifically at this illustrated excitation time) points in the opposite direction as the force vector F of the second unbalance exciter unit; the two force vectors F point towards one another; the unbalance exciter units rotate in the same direction. The phase offset is 180°; a resulting excitation force Fr (resulting cluster vector) is zero (forceless).

Fig. 4A describes an operating state which can be set/regulated, for example, for powerless startup or shutdown through the resonance range of the device.

Fig. 4B shows a cluster in which the force vectors F point in the same direction; the unbalance exciter units rotate in the same direction. A resulting cluster force vector Fr also points in the same direction as the force vectors F, in particular horizontally to the right. The phase offset is 0° or does not exist; a resulting excitation force Fr (resulting cluster vector) is maximally large.

Fig. 4C shows a cluster in which the force vectors F are aligned orthogonally to one another, in particular horizontally to the right and vertically upwards; the unbalance exciter units rotate in the same direction (here: clockwise). An instantaneous cluster force Fr resulting from the cluster oscillation points diagonally upwards, in particular to the top

12 20715796.7 right at an angle of approximately 35°. The phase offset is between 0° and 180°; The resulting excitation force Fr for the respective cluster results from vector addition and is smaller than the absolute excitation force acting in Fig. 4B.

Fig. 4D shows a cluster in which the force vectors F are aligned orthogonally to one another, in particular horizontally to the right and vertically upwards; the second (right) force vector is longer/larger than the first (left) force vector; the unbalance exciter units rotate in the same direction. A first resulting excitation force Fr points horizontally to the right in the same direction as the first (left) force vector F. A second resulting excitation force Fr points diagonally upwards, in particular to the top right at an angle of approximately 45°, The phase offset is between 0° and 180° and can also be 0° or 180°; an excitation force Fr resulting for the respective cluster results from vector addition. Fig. 4D describes a control in which the individual vector amounts are adjusted by varying the speed of the respective unbalance exciter unit; the speed can be squared to define the centrifugal force acting in each case. In Fig. 5A, both force vectors F point upwards, in particular vertically upwards; the unbalance exciter units rotate in opposite directions to each other. A phase shift is not realized (0°); the cluster excitation is in vertical direction. Fig. 5A describes an operating state which can be set/controlled, for example, for a cleaning function, in particular in connection with a variation of the speed of the respective unbalance exciter unit. In Fig. 5B, the (first) left force vector F points upwards, and the (second) right force vector F points to the left, in particular orthogonal to the left force vector F; the unbalance exciter units rotate in opposite directions to one another. The phase offset here is, for example, 90°; a resulting cluster excitation acts at an angle of 45° to the horizontal. List of Reference Numerals: 1 screening device 2 screening box 31 sidewall 32 — side wall 4 oscillation system cluster 41 unbalance exciter unit

13 20715796.7 truss 6 screening deck 7 actuating and controlling device P coupling point 5 F force vector Fr resulting excitation force (resulting cluster force vector) x conveying direction