BE1029527A1 - Emergency shutdown of a screening device in the event of a malfunction of an unbalance exciter unit - Google Patents

Abstract

The present invention relates to a method for emergency shutdown of a screening device 10, the screening device 10 having at least four clusters of imbalance exciter units 61, 62, 63, 71, 72, 73, each cluster having at least two imbalance exciter units 61, 62, 63, 71, 72, 73, each cluster being formed via a coupling point for subjecting the screening device 10 to vibrations, with two front clusters being arranged closer to the material application 20, with two rear clusters being arranged closer to the material discharge 30, characterized in that in the event of a defect one Unbalance exciter unit 61, 62, 63, 71, 72, 73 in each cluster an unbalance exciter unit 61, 62, 63, 71, 72, 73 is deactivated.

Description

' BE2021/5495 Emergency shutdown of a screening device in the event of a malfunction of an imbalance exciter unit The invention relates to a method for switching off a screening device in a controlled manner in the event of failure or an error message leading to a forced shutdown of an imbalance exciter unit, so that the defective imbalance exciter unit can then be repaired and the screening device started again easily and sure is possible.

Screen systems with vibration exciters arranged in groups are known from DE 10 2017 218 371 B3 and from DE 10 2018 205 997 A1. This arrangement in groups enables the operation of the screening device to be highly adaptable, which is not possible with the classic linear, elliptical or circular vibrators. This group of screening devices thus enables completely new control schemes.

DE 10 2019 204 845 B3 discloses a method for setting and controlling at least one vibration mode of a screening device.

A method for controlling and regulating a screening device is known from DE 10 2019 214 864 B3.

From the post -publiced DE 10 2021 204 377, DE 10 2021 204 388, DE 10 2021 204 390, DE 10 2021 204 391, DE 10 2021 204 392, DE 10 2021 204 393 and DE 10 2021 204 396 Various control methods for screening systems with vibration exciters arranged in groups are known.

It is currently customary to stop a screening device immediately as soon as an imbalance exciter unit has a defect or a sensor indicates that this imbalance exciter unit is malfunctioning. This is intended to prevent further damage to the imbalance exciter unit or even to the entire screening device. However, the disadvantage of this sudden shutdown is that the material to be screened remains on the screen. A further complication is that the device supplying material to the screening device, for example a conveyor belt, usually cannot be stopped immediately and the amount of material on the screening device is thus increased even further.

The object of the invention is to provide a method with which a screening device with vibration exciters arranged in groups can be shut down in a controlled manner if a vibration exciter fails or is faulty.

This problem is solved by the method with the features specified in claim 1 .

Advantageous developments result from the dependent claims, the following description and the drawings.

The method according to the invention is used for the emergency shutdown of a screening device.

Corresponding screening devices are used, for example, when mining material, but in particular in combination with an upstream crusher or an upstream mill.

The screening device is typically used to separate a coarse fraction and a fine fraction.

The coarse fraction runs over the screen, while the fine fraction is guided downwards through the screen.

For example, a screening device can also have two screens arranged one above the other.

The upper sieve is correspondingly coarse, the lower one is finer.

In this case, an additional middle fraction is separated.

The screening device has at least four clusters of imbalance exciter units.

The imbalance exciter units serve to set the screen of the screening device in motion and thus to move the material to be screened on the screen.

Each cluster has at least two imbalance exciter units, each cluster being designed via a coupling point for impinging the screening device with vibrations.

Due to the joint coupling into a common coupling point, the overall acceleration resulting from the imbalance exciter units is transferred to the coupling point on the system, resulting in a variety of control options.

The two front clusters are located closer to material application and the two rear clusters are located closer to material discharge.

In addition, the screening device can have further clusters, for example screening devices can also have six or eight clusters, which are preferably arranged in pairs opposite one another and equidistant from one another.

According to the invention, an unbalance exciter unit in each cluster is deactivated in the event of a defect in an unbalance exciter unit.

The effect is that the number of imbalance exciter units in each cluster is reduced by 1, for example from two imbalance exciter units to one imbalance exciter unit or from three imbalance exciter units to two imbalance exciter units.

Thus, all clusters are of the same type again and all active imbalance exciter units are fully functional.

Of course, this reduces the energy that can be introduced into the screening device, so that the efficiency is reduced.

The controllability of the screening device is also reduced, for example when two imbalance exciter units are reduced to just one imbalance exciter unit, the cluster naturally only has the invariable property of one imbalance exciter unit.

The advantage, however, is that the screening device is still functional and controllable, so that at least the material on the screen can be pre-processed.

As a result, the screening device is then empty and can be repaired much more easily, and it is also easier to start up again.

In a further embodiment of the invention, the imbalance exciter units are arranged in all clusters in the same spatial arrangement relative to the material application and material discharge.

In each cluster, the imbalance exciter unit that is located at the same spatial position within the cluster as the imbalance exciter unit with the defect within the cluster in which it is arranged is deactivated.

This is explained using an example.

Assuming that the screening device has four clusters, each with two unbalance exciter units, the material application is on the left, the material discharge is on the right, and the two unbalance exciter units in a cluster on the right and left side by side.

If, for example, the left imbalance exciter unit in a cluster were to fail, the left imbalance exciter units would be switched off in all clusters.

Thus, the screening device still has four running imbalance exciter units, each of which is on the right in the cluster.

In this way, the screening device can continue to operate in an emergency mode until the screen is empty.

The defective imbalance exciter unit can then be easily repaired or replaced.

Furthermore, this symmetrical shutdown enables simple control in emergency operation.

In a further embodiment of the invention, each cluster has three imbalance exciter units, with the two imbalance exciter units still remaining after deactivation being operated at the same speed, in opposite directions of rotation and with a phase offset of 90°.

This control enables maximum material transport over the screen so that the screening device is emptied as quickly as possible.

In a further embodiment of the invention, the defect in an imbalance exciter unit is determined by detecting a sharp drop in the speed, the power consumption increasing rapidly, and/or a sensor, for example a temperature sensor, detecting a malfunction, for example overheating.

In a further embodiment of the invention, each imbalance exciter unit has an initial sensor, a sensor which reports the exact point in time of the position of the sensor to a control system once per revolution.

The disadvantage of such an initial sensor compared to incremental encoders or absolute encoders, which can report several positions or the exact position of the unbalance exciter unit to a control system, is the much lower data density, since only one piece of information is available per revolution, which makes control more difficult.

However, this disadvantage has to be accepted, since an initial sensor is significantly more robust in comparison to the other types of sensors and the initial sensor is arranged on the imbalance exciter unit and thus in the area of the screening device that is subjected to high mechanical loads.

In one embodiment, the defect in an imbalance exciter unit is detected in that the time span since the last signal is more than twice as long as the expected time interval for one revolution.

In a further embodiment of the invention, in the event of a defect in an imbalance exciter unit, a control signal is sent to the device feeding the screening device with material to end the application of material to the screening device.

For example, the device feeding the screening device with material is a conveyor belt.

More preferably, all upstream processes are controlled accordingly and terminated step by step.

If, for example, a crusher is fed via a first conveyor belt and the crushed material via a second

Conveyor belt promoted to the screening device according to the invention, the first conveyor belt is preferably stopped first. The crusher is then stopped as soon as it has run empty, followed by the second conveyor belt. After that, the screening device continues to be operated until it has also run empty 5 . Thus, both the crusher and the screening device are in a state in which they can be easily started up again. In a further embodiment of the invention, the device feeding the screening device with material sends a signal to the screening device about the end of the application of material, the screening device continuing to be operated after the end of the application of material until the screening device is emptied. As already explained above, this can also relate to more than one upstream device, for example the first conveyor belt, the crusher and the second conveyor belt from the example mentioned above.

A device for the method according to the invention is explained in more detail below with reference to an exemplary embodiment illustrated in the drawings. 1 first example FIG. 2 first example after failure FIG. 3 first example in emergency operation FIG. 4 second example FIG. 5 second example after failure FIG Sieve device 10. The sieve device 10 has a first cluster with a first first imbalance exciter unit 61 and a second first imbalance exciter unit 62, and a second cluster with a first second imbalance exciter unit 71 and a second second imbalance exciter unit 72. The third cluster and the fourth cluster are respectively arranged directly behind the first cluster and the second cluster in this side view. A conveyor belt 50 transports material to the screening device 10. At the material application 20, the material is applied to the screen of the screening device. Fine material falls through the screen and is discharged via the fine fraction discharge 40.

The coarse fraction is transported to the material outlet 30 via the screen of the screening device 10 .

1 shows that the first unbalance exciter unit 61 and the second first unbalance exciter unit run with a phase offset of 90° and in opposite directions at the same speed.

This applies analogously to the first second imbalance exciter unit 71 and the second second imbalance exciter unit 72. If, for example, the second imbalance exciter unit 62 fails, as shown in Fig. 2, the right imbalance exciter units pointing to the material outlet 30 are deactivated in Fig. 3 this is shown for the second second imbalance exciter unit 72, the third and fourth clusters cannot be seen.

As a result, the screening device 10 with the first imbalance exciter unit 61 in the first cluster, the first second imbalance exciter unit 71 in the second cluster, the first third imbalance exciter unit in the third cluster and the first fourth imbalance exciter unit in the fourth cluster can continue to be operated in emergency mode until the material is applied by the Conveyor belt 50 has ended and the screening device 10 itself has run empty.

The second example, as shown in FIGS. 4 to 6, differs from the first example, which is shown in FIGS. 1 to 3, in that each cluster has three imbalance exciter units.

4 shows an exemplary operation in which the first first unbalance exciter unit 61 has one direction of rotation and the second first unbalance exciter unit 62 and the third first unbalance exciter unit 63 have the opposite direction of rotation.

The three first imbalance exciter units 61, 62, 63 all have the same phase and rotational speed.

The second cluster is operated in the same way.

The first second unbalance exciter unit 71 has one direction of rotation and the second second unbalance exciter unit 72 and the third second unbalance exciter unit 73 have the opposite direction of rotation.

The three second imbalance exciter units 71, 72, 73 all have the same phase and rotational speed.

If, for example, the second first imbalance exciter unit 62 fails, as shown in FIG. 5, then all second nth imbalance exciter units 62, 72 in all clusters are switched off.

In addition, a phase offset of 90° is set between the first n-th unbalance exciter units 61, 71 and the third n-th unbalance exciter units 63, 73, as in Fig. 6

/ BE2021/5495 shown. This maximizes the transport of material via the screening device 10 and thus reduces the loss of power due to the switching off of the second nth imbalance exciter units.

Reference sieve device 20 material application 30 material discharge 40 fine fraction discharge 10 50 conveyor belt 61 first first imbalance exciter unit 62 second first imbalance exciter unit 63 third first imbalance exciter unit 71 first second imbalance exciter unit 72 second second imbalance exciter unit 73 third second imbalance exciter unit

Claims (6)

patent claims 1. A method for emergency shutdown of a screening device (10), the screening device (10) having at least four clusters of imbalance exciter units (61, 62, 63, 71, 72, 73), each cluster having at least two imbalance exciter units (61, 62, 63, 71, 72, 73), each cluster being formed via a coupling point for impinging the screening device (10) with vibrations, two front clusters being arranged closer to the material application (20), two rear clusters being closer to the material discharge (30) are arranged, characterized in that in the event of a defect in an imbalance exciter unit (61, 62, 63, 71, 72, 73) in each cluster an imbalance exciter unit (61, 62, 63, 71, 72, 73) is deactivated. 2. The method according to claim 1, characterized in that the imbalance exciter units (61, 62, 63, 71, 72, 73) are arranged in all clusters in the same spatial arrangement relative to the material application (20) and the material discharge (30), wherein in each cluster the imbalance exciter unit (61, 62, 63, 71, 72, 73) which is located at the same spatial position within the cluster as the imbalance exciter unit (61, 62, 63, 71, 72, 73) is deactivated the defect within the cluster in which it is located. 3. Method according to one of the preceding claims, characterized in that each cluster has three imbalance exciter units (81, 62, 63, 71, 72, 73), the two imbalance exciter units (61, 62, 63, 71, 72, 73) can be operated with the same speed, opposite direction of rotation and a phase shift of 90°. 4. The method according to any one of the preceding claims, characterized in that the defect of an imbalance exciter unit (61, 62, 63, 71, 72, 73) is determined in that a sharp drop in the speed is detected, the power consumption increases rapidly, and / or a sensor, for example a temperature sensor, detects a malfunction, for example overheating. 5. The method according to any one of the preceding claims, characterized in that if an imbalance exciter unit (61, 62, 63, 71, 72, 73) is defective, a control signal is sent to the device feeding the screening device (10) with material to end the application of material (20 ) is sent to the screening device (10). 6. The method according to claim 5, characterized in that the device feeding the screening device (10) with material sends a signal to the screening device (10) about the end of the application of material (20), the screening device (10) after the end of the application of material ( 20) until the screening device (10) is emptied.