WO2023247100A1

WO2023247100A1 - Control system for a steep conveyor system

Info

Publication number: WO2023247100A1
Application number: PCT/EP2023/061719
Authority: WO
Inventors: Stefan Hinterholzer; Claus BUTTER
Original assignee: Lhb Mining Solutions Gmbh
Priority date: 2022-06-24
Filing date: 2023-05-03
Publication date: 2023-12-28
Also published as: DE102022115836A1; DE102022115836B4

Abstract

The present invention relates to a conveyor system (100) for conveying material (101). The conveyor system (100) comprises a conveyor belt (102) comprising a conveyor surface, onto which the material (101) to be conveyed are placeable, wherein the conveyor belt (102) is movable along a conveying direction (103) between a feeding station (104), at which the material (101) is placeable, and a removing station (105), form which the material (101) is removable from the conveyor surface. A load determination device (106) determines the actual load acting onto the conveyor belt (102) at the location of the load determination device. A driving unit (110) drives the conveyor belt (102). A control device (107) controls the driving unit (110) in such a way that a predetermined driving torque (Mn) is generatable and transferrable by the driving unit (110) to the conveyor belt (102), wherein the control device (107) is further configured to determine on the basis of the speed of the conveyor belt (102) and the distance between the location of the load determination device and the driving unit (110) along the conveying direction (103)the load acting onto the conveyor belt (102) between the location of the load determination device and the driving unit (110) and to determine the required driving torque (Mn) of the driving unit (110) for driving the conveyor belt 20 (102) on the basis of the load between the location of the load determination device and the driving unit (110).

Description

Control system for a steep conveyor system

Field of invention

The present invention relates to a conveyor system for conveying material, and a respective method for controlling a conveyor system for conveying material.

Art Background

Conveying systems for steeply ascending conveyors are known, which comprise along a conveyor belt a plurality of decentralized driving units that initiate the driving torque required for operation and for driving the conveyor belt.

The driving units are coupled to the conveyor belt spaced apart from each other. Generally, each driving unit transfers a similar driving torque to the conveyor belt for controlling the conveyor belt with a certain speed. However, due to the varying loads acting along the conveyor belt due to the inconstant weight of the material placed onto the conveyor belt and the possible varying inclination of the conveyor belt along the conveying direction, the tension of the conveyor belt exceeds certain limits, especially if a huge driving torque is induced into the conveyor belt at regions, where a high load acts onto the conveyor belt.

Hence, if each driving unit transfers a predefined driving torque regardless of the operation conditions and loads acting on the conveyor belt along the conveying direction, high stress may be generated in certain regions of the conveyor belt which may cause damages. Summary of the Invention

Hence, it may be an object of the present invention to provide a conveyor system having a smooth driving system for reducing stress in the conveyor belt caused by inducing driving torque.

This object is solved by a conveyor system for conveying material and by a method for controlling the conveyor system according to the subject matter of the independent claims.

According to a first aspect of the present invention, a conveyor system for conveying material is presented. The conveying system comprises a conveyor belt comprising a conveyor surface, onto which the material to be conveyed are placeable, wherein the conveyor belt is movable along a conveying direction between a feeding station, at which the material is placeable, and a removing station, form which the material is removable from the conveyor surface.

The conveying system further comprises a load determination device, coupled to the conveyor belt for determining the actual load acting onto the conveyor belt at the location of the load determination device. Furthermore, the conveying system further comprises a driving unit for driving the conveyor belt, wherein the driving unit is coupled to the conveyor belt in conveying direction after the load determination device.

Furthermore, the conveying system comprises a control device coupled with the load determination device and the driving unit, wherein the control device is configured for controlling the driving unit in such a way that a predetermined driving torque is generatable and transferrable by the driving unit to the conveyor belt. The control device is further configured to determine on the basis of the speed of the conveyor belt and the distance between the location of the load determination device and the driving unit along the conveying direction, the load acting onto the conveyor belt between the location of the load determination device and the driving unit.

The control device is further configured to determine the required driving torque of the driving for driving the conveyor belt on the basis of the load (i.e. a load sequence) between the location of the load determination device and the driving unit.

According to a further aspect of the present invention a method for controlling a conveyor system for conveying material. The method comprises the step of placing material to be conveyed into a conveyor surface of a conveyor belt, wherein the conveyor belt is movable along a conveying direction between a feeding station, at which the material is placeable, and a removing station, form which the material is removable from the conveyor surface.

The method further comprises the step of determining an actual load acting onto the conveyor belt at a location of the load determination device by a load determination device coupled to the conveyor belt and of driving the conveyor belt by a driving unit, wherein the driving unit is coupled to the conveyor belt in conveying direction after the load determination device.

The method further comprises the step of controlling the driving unit by a control device, which is coupled with the load determination device and the driving unit, in such a way that a predetermined driving torque is generatable and transferrable by the driving unit to the conveyor belt. Furthermore, the driving unit is controlled by the control device in such a way that a predetermined driving torque is generatable and transferrable by the driving unit to the conveyor belt, wherein, by the control device, on the basis of the speed of the conveyor belt and the load acting onto the conveyor belt between the location of the load determination device and the driving unit and to determine the required driving torque of the driving unit for driving the conveyor belt on the basis of the load between the location of the load determination device and the driving unit.

The conveying system according to exemplary embodiments of the invention serves to convey a material, such as an item or good, which has a high weight and is in particular to be conveyed with a vertical directional component. The material can for example consist of rocks or boulders or other bulk materials with large dimensions and high weights.

The conveying system comprises a conveyor belt. The conveyor belt can for example consist of a conveyor band or a belt conveyor, a conveyor chain or a conveyor band consisting of a plurality of conveying members. A conveying profile, such as for example a profiled surface, a conveyor surface in the style of an elevator conveyor or other carrying elements for carrying the conveyed material, can be arranged on the conveyor surface of the conveyor belt.

The conveyor belt is movable along a conveying direction. Hereinafter, transverse to or across the conveying direction and along the width of the conveyor belt is defined as the transverse direction of the conveyor belt.

The material is conveyed along the conveying direction between a feeding station and a removing station, wherein the conveyor belt is deflected e.g. by a feeding or removing pulley at the feeding station and the removing station. Alternatively, the conveyor belt can be coiled or rolled up and decoiled or unwound at one of its ends. Furthermore, at the feeding station a loading hopper may be arranged for filling the material, e.g. bulk material, to the conveyor belt. The driving unit comprises for example a driving pulley that is pressed or engaged by a coupling profile with the conveyor belt such that upon rotation of the driving pulley, the respective driving torque for driving the conveyor belts can be transferred. As described in an exemplary embodiment below, between the conveyor belt and the driving pulley, a respective drive belt may be interposed. The driving unit may be electrically driven. However, it could also be possible to drive the driving unit in a hydraulic or pneumatic manner. Specifically, a plurality of driving units may be arranged one after another along the conveyor belt for transferring driving torque to the driving belt.

The driving unit is configured to generate a driving torque in order to thereby drive the conveyor belt. The driving torque can on the one hand be used to drive the conveyor belt, in particular in case of a certain slope or inclinations of the driving belt, where the material is conveyed from a lower feeding station to a higher removing station. The driving torque can also be utilized as a braking force. The driving unit is thus utilized as a brake which counteracts the movement of the conveyor belt. For example, it is necessary that the conveyor belt is braked when a material is transported from a higher feeding station to a lower removing station, in order to keep the speed of the conveyor belt constant or to reduce it. A driving unit can thereby be formed as an electromotor which can also be operated as a generator. The driving unit can further comprise a magnet brake or an eddy current brake, for example. Due to the coupling of the conveyor belt with the driving unit, a robust force transmission can thus be provided, such that the conveyor system is utilizable for heavy materials.

Furthermore, according to the present invention, a load determination device is coupled to the conveyor belt specifically in or in the vicinity to the feeding station. The load determination device measures the load, e.g. the weight, of the material at the time point, when the material passes the location of the load determination device. The load determination device may form for example a belt scale device, wherein for example the weight acting on the conveyor belt is transferred to weighting elements of the belts scale device that can physically measure the weight of the goods arranged on the conveyor belt. Furthermore, the load determination device may determine the volume of the goods onto the conveyor belt by a radar or laser sensors and together with the knowledge about the kind of conveyed goods, the respective loads, i.e. weight, can be determined. Hence, it is known, which load, e.g. weight, of material is arranged onto a certain section of the conveyor belt.

The control device is coupled to the load determination device for receiving the weight information and hence receives the information which section of the conveyor carries a material of a defined and measured weight. Furthermore, the control device is coupled to the driving unit and, if a plurality of driving units are used, to some or all driving units. The control device is configured for controlling the driving unit and hence controlling the driving torque generated by the driving unit and transferred to the conveyor belt at the location, where the respective driving unit is coupled to the conveyor belt.

Additionally, the control device is coupled to a respective speed sensor arranged at the conveyor belt for determining the actual speed of the conveyor belt along the conveying direction.

Hence, the control device receives as an input parameter the respective weight (e.g. in tons t) of material at specific locations along the conveyor belt and receives as an input parameter the actual speed (m/s) and/or the setpoint speed of the conveyor belt. Based on these input parameters, the control device determines between the location of the load determination device and the location of the one or the plurality of driving units along the conveying direction the respective load and load distribution along the conveying direction. Accordingly, the control device is aware of the distance between the load determination device and the respective driving units along the conveying direction and the load acting onto the conveyor belt along the conveying direction.

Hence, based on the determined load distribution (i.e. load sequences) acting on the conveyor belt along the conveying direction, specifically between the load determination device and a respective driving unit or between two adjacent driving units, the control device determines the driving torque that has to be generated by a driving unit at a certain time point . Hence, the control device determines a required and necessary driving torque (Nm) for the driving unit at a time point where the determined loads acting along the conveyor belt such that the required driving torque drives the conveyor belt with a predefined speed and such that the driving torque does not exceed for example a critical maximum driving torque which could damage the conveyor belt.

Hence, by the approach of the present invention, the control device and the driving unit do not only generate a constant driving torque in order to reach a predefined speed of the conveyor belt but the driving unit determined to a varying driving torque which is based on a varying load/weight of material acting on the conveyor belt along the conveying direction. Hence, the conveyor belt is driven with a more gentle driving torque under consideration of the actual weight of material along a specific section of the conveyor belt, e.g. between the load determination device and a respective driving unit or between two adjacent the driving units.

According to a further exemplary embodiment, the conveyor system comprises a further subsequent driving unit for driving the conveyor belt, wherein the further driving unit is coupled to the conveyor belt in conveying direction after the driving unit . The control device is further coupled with the further driving unit in such a way that a further predetermined driving torque is generatable and transferrable by the further driving unit to the conveyor belt, wherein the control device is further configured to determine on the basis of the speed of the conveyor belt, the distance between the location of the load determination device (or the driving unit) and the further driving unit along the conveying direction the load acting onto the conveyor belt between the driving unit and the further subsequent driving unit and to determine the required driving torque (Mn) of the further subsequent driving unit for driving the conveyor belt on the basis of the load between the driving unit and the subsequent further subsequent driving unit.

With the above-described embodiment a conveyor system is outlined comprising a plurality of driving units, wherein all driving units are spaced apart from each other along the conveying direction. The control device determines on the basis of the speed of the conveyor belt and on the basis of the location of the further driving unit the load acting on the conveyor belt between the load determination device and a respective driving unit or between two adjacent the driving units . Based on this information, the control device regulates the required further driving torque at the further driving unit.

According to a further exemplary embodiment, the control device is further configured to adjust the required driving torque of the driving unit independently with respect to the required further driving torque of the further driving torque. Hence, the control device controls the driving units independent from each other such that each driving unit transfers and generates the respective driving torque that is adapted to the load acting onto the conveyor belt when passing the respective driving unit. For example, based on the load acting on the conveyor belt between the load determination device and the one driving unit, the generated driving torque may be higher with respect to a driving torque of another subsequent driving unit, where at the moment the load of the conveyor belt between two adjacent the driving units is lower such that less driving torque is necessary for driving the conveyor belt. Alternatively, based on the load acting on the conveyor belt between the load determination device and the one driving unit, the generated driving torque may be reduced with respect to a driving torque of another subsequent driving unit, where at the moment the load of the conveyor belt between two adjacent the driving units is lower such that a higher driving torque can be applied for driving the conveyor belt without exceeding a critical maximum load of the conveyor belt.

According to a further exemplary embodiment at least one of the driving unit and the further driving unit is selectively decouplable from the conveyor belt. If a driving unit is decoupled from the conveyor belt, the driving torque is transferred to the conveyor belt anymore. Hence, if the control device determined, that a required driving torque can be generated by one driving unit without exceeding a critical maximum load of the conveyor belt, a further driving unit may be decoupled from the conveyor belt in order to save energy and reduce wear, for example. Furthermore, also in case of damages of a driving unit, the damage driving unit may be decoupled and the control device determined an updated required driving torque for the working driving units in order to provide a sufficient general driving torque for still driving the conveyor belt. For example if an intermediate driving unit located between the load determination device and the subsequent further driving device is decoupled, the load acting on the conveyor belt between the load determination device and the further driving unit is determined. Based on that load section, the further driving torque of the further driving unit is determined.

According to a further exemplary embodiment, the conveyor belt comprises an inclination section having a determined inclination (for example an angle of 10° to 80°, in particular 45° between the conveying directions and a horizontal direction), wherein the material is lifted along the conveying direction. The driving unit is coupled to the conveyor belt at the inclination section, wherein the control device determines the required driving torque additionally on the basis of the inclination of the conveyor belt along the inclination section, i.e. between the load determination device and a respective driving unit or between two adjacent driving units, the location of the driving unit.

At inclined regions of the conveyor belt, the load acting on the conveyor belts by the weight of the material is higher than at horizontal regions of the conveyor belt, since the conveyor belt must additionally lift the material along a vertical component. However, by the above-described embodiment, the control device considers the inclination of the conveyor belt along an inclination section, i.e. between the load determination device and a respective driving unit or between two adjacent driving units, such that either an increased driving torque is generated or a reduced driving torque is generated for reducing the loads acting on the conveyor belt due to the inclination.

According to a further exemplary embodiment the conveyor belt comprises a declination section having a determined declination, wherein the material is lowered along the conveying direction. The driving unit is coupled to the conveyor belt at the declination section. The control device determines the required driving torque additionally on the basis of the declination of the conveyor belt at along the declination section, i.e. between the load determination device and a respective driving unit or between two adjacent driving units. Hence, the control device considers the declination of the conveyor belt along the declination section where the driving unit is coupled to the conveyor belt such that either an increased driving torque is generated or a reduced driving torque is generated for reducing the loads acting on the conveyor belt due to the declination. Specifically, the control device reduces the driving torque in a respective declination section, since due to the weight of the material passing the driving units, a slope downforce is generated by the weight of the material such that the driving torque of the driving unit has to be adapted and reduced, respectively. In specific cases, the driving unit generates a driving torque acting in counter direction with respect to the conveying direction such that the driving unit acts as a brake for the conveyor belt.

Specifically in declination sections of the conveyor belts, the driving unit may be constructed as a brake unit. The driving unit can thereby be formed as an electromotor which can also be operated as a generator. The driving unit can further comprise a magnet brake or an eddy current brake, for example. Due to the coupling of the conveyor belt with the driving unit, a robust force transmission can thus be provided, such that the conveyor system is utilizable for heavy materials.

According to a further exemplary embodiment, the feeding station is located at a lower level than the removing station. Hence, the conveyor system is designed for lifting the material. Alternatively, the feeding station is located at a higher level than the removing station.

According to a further exemplary embodiment, the control device is configured to adjust the required driving torque dependent on the load acting on the conveyor belt between the location of the load determination device and the driving unit for keeping the speed of the conveyor belt constant. Hence, as a target for the driving units, the constant conveyor belt speed may be defined. Hence, dependent on the load acting on the conveyor belt when passing the driving unit, a customized and specific driving torque has to be adjusted for each driving unit such that a constant speed of the conveyor belt along the whole conveying direction can be adjusted. Otherwise, if each driving unit would generate the same driving torque without considering the respective load sections of the conveyor belts, some driving units, where the load of the conveyor belt is lower, would generate by the respective driving torque a higher speed of the conveyor belt and some driving units, where the load of the conveyor belt is higher, would generate by the respective driving torque a lower speed of the conveyor belt. Hence, due to the different induced speeds, the conveyor belt comprise zones and stretched zones which would cause damaging stress for the conveyor belt.

According to a further exemplary embodiment, the control device is configured to adjust the required driving torque dependent on the load acting on the conveyor belt between the location of the load determination device and the driving unit the driving unit for increasing or decreasing the speed of the conveyor belt. Hence, specifically if the conveyor belt is started or stopped, as a target for the driving units, the increasing or decreasing of the speed may be defined. It is therefore an aim to generate a constant and smooth acceleration or deceleration of the conveyor belt. Therefore, based on the respective load acting onto the driving units, a respective required and individual driving torque for each driving unit may be determined in order to provide a smooth acceleration or deceleration of the conveyor belt.

According to a further exemplary embodiment, the conveyor belt forms a closed loop, wherein the feeding station comprises a feeding pulley and the removing station comprises a removing pulley. The conveyor belt is wound around the feeding pulley and the removing pulley.

According to a further exemplary embodiment, at least one of the feeding pulley and the removing pulley is free of driving means and rotatable by the movement of the conveyor belt. Alternatively, at least one of the feeding pulley and the removing pulley may form a respective driving unit for driving the conveyor belt and for generating respective driving torque. In this case, the respective pulley is also controlled by the control device in order to generate the required driving torque. According to a further exemplary embodiment, at least one of the feeding pulley and the removing pulley is adjustable for tensioning the conveyor belt. Hence, the tension of the conveyor belt may be adjusted particular with respect to the overall load acting onto the conveyor belt due to the weight of the material to be transported.

According to a further exemplary embodiment, the control device is configured to adjust the speed of the conveyor belt within a predetermined maximum driving torque. According to a further exemplary embodiment, the control device is configured to increase the further driving torque of the further driving unit if the driving torque of the driving unit reaches the maximum driving torque range. Based on the load acting on the conveyor belt between the load determination device and a respective driving unit or between two adjacent driving units , the generated driving torque may be reduced with respect to a driving torque of another driving units, where at the moment the load of the conveyor belt is lower such that a higher driving torque could be applied for driving the conveyor belt without exceeding a critical maximum load of the conveyor belt.

According to a further exemplary embodiment the conveyor belt comprises a coupling surface comprising a first coupling profile, wherein the driving unit comprises a driving belt having a second coupling profile. A part of the second coupling profile of the driving belt extends parallel to the coupling surface of the conveyor belt in such a way that the first coupling profile engages with the second coupling profile in an interlocking manner along the coupling portion of the conveyor belt. In particular at least one of the first coupling profile and the second coupling profile is formed as a toothed belt profile.

The conveyor belt further forms the first coupling profile which engages in an interlocking coupling by means of a second coupling profile of the driving belt.

The first coupling profile and the corresponding second coupling profile can for example comprise a corresponding toothed profile. The first coupling profile or the second coupling profile can further comprise other engaging structures, such as for example a rod element, which extends transverse to a conveying direction of the conveyor belt.

The first coupling profile may be formed along the entire length of the conveyor belt. The first coupling profile can for example be releasably or detachably fastened to the conveyor belt, for example by means of a screw connection. The coupling profile can further be glued or soldered to the conveyor belt. Furthermore, it is possible that the conveyor belt is formed together with the first coupling profile and that the conveyor belt and the first coupling profile thereby form an integral and monolithic unit. The conveyor belt can for example be manufactured from a robust and flexible plastic material and/or rubber material.

For the force coupling, the first coupling profile is coupled to the second coupling profile in an interlocking manner, in order to thereby cause a precise and robust force transmission to the conveyor belt. The driving torque can on the one hand be utilized as a driving force in order to drive the conveyor belt, in particular in case of a certain slope or inclination, where the material is to be conveyed from a lower starting point to a higher ending point. Due to the interlockingly engaging coupling, the driving torque can also be utilized as a braking force. The driving belt driven by a conveying drive is thus utilized as a brake which counteracts the movement of the conveyor belt. For example, it is necessary that the conveyor belt is braked when a to be conveyed good is transported from a higher starting point to a lower ending point, in order to keep the speed of the conveyor belt constant or to reduce it. A conveying drive can thereby be formed as an electromotor which can also be operated as a generator. The conveying drive can further comprise a magnet brake or an eddy current brake, for example. Due to the interlockingly engaging coupling of the conveyor belt with the conveying drive, a robust force transmission can thus be provided, such that the conveying system is utilizable for heavy to be conveyed goods.

According to a further exemplary embodiment the driving belt forms a closed loop which is guided around two circulating rollers which are spaced apart from each other, wherein in particular one of the circulating rollers is a driven roller forming a conveying drive.

A portion of the driving belt extends parallel to a coupling portion of the conveyor belt which comprises the first coupling profile, wherein the driving belt forms the second coupling profile in such a way that the driving belt engages with the conveyor belt in an interlocking manner along the coupling portion of the conveyor belt.

When using the driving belt according to exemplary embodiments of the invention, the driving torque is not transmitted punctually or in a point by point manner but instead along an elongated coupling portion. Thereby, the driving torque can be gently transmitted as no punctual force peaks occur when the driving torque is transmitted. This causes less strain on the conveyor belt and accordingly to a more robust conveyor system.

The rotational axes of the circulating rollers are arranged on a common central axis. At least one of the circulating rollers can be formed as a drive drum or a drive roller. These apply the driving torque, for example as a driving force or a braking force, and transmit it to the driving belt. The driving belt is arranged and formed such that at least a portion of the driving belt is coupled with the first coupling profile at the leader portion and a further portion of the driving belt is coupled with the first coupling profile at the return portion of the conveyor belt. According to a further exemplary embodiment, the conveying system comprises a tensioning device for adjusting the distance between the circulating rollers for tensioning the driving belt. The circulating rollers may be mounted to a common supporting frame, wherein one of the circulating rollers may be movably coupled to the supporting frame in order to be movable to and away from the other circulating roller. Thereby, a predetermined pretensioning force of the driving belt may be adjusted depending on the distance of the circulating rollers. The other circulating roller which is not movable with respect to the movable circulating roller may form the driven conveyor drive, e.g. a driven circulating roller.

The tensioning device may comprise for example a spindle drive, a cable drive system, a hydraulic system including a hydraulic adjustment cylinder controlling an adjusting piston or an electrical linear motor for moving the circulating roller along the supporting frame in order to tensioning the driving belt. Depending on the load acting on a certain load section, for example between the load detection unit and the driving unit or between further driving units, the respective tensioning of the driving belt is to be adjusted in order to transmit effectively the driving torque to the conveyor belt. Additionally, if the coupling profiles form toothed profiles it may be necessary to provide a predetermined pre-tensioning force of the driving belt in order to enable a curried matching of the toothed profiles of the first and second coupling profile.

According to a further exemplary embodiment, the control device is configured for controlling the tensioning device for tensioning the driving belt on the basis of the driving torque of the driving unit for driving the conveyor belt on the basis of the load between the location of the load determination device and the driving unit. For example, in conventional approaches, the pretensioning force of the driving belt is adjusted with respect to a maximum driving torque that can be transmitted from the driving belt to the conveyor belt. Furthermore, as a parameter for pretensioning the driving belt, the rate of the transported goods on the conveyor belt were considered. However, it has found out in the present invention, that the relevant factor for providing an exact coupling between the coupling profiles of the conveyor belt and the driving belt is the transmitted driving torque transmitted from the driving belt to the conveyor belt. Hence, by the described exemplary embodiment, the pretensioning force can be adjusted on the basis of the driving torque transmitted by the driving unit to the conveyor belt. Hence, a perfect matching of the respective coupling profiles of the conveyor belt and the driving belt came the achieved by adjusting the pretensioning force of the driving belt.

Additionally, respective torque sensors and stain gauges may be coupled to the conveyor belt for measuring the load and the stress acting onto certain regions of the conveyor belt. The control device may be coupled to the respective torque sensors and/stain gauges and may adapt the driving torque of a respective driving unit in order to reduce the stress or reparations of the conveyor belt.

Summarizing, modular, decentralized driving units initiate the forces, i.e. driving torque required for operation into the conveyor belt at specific intervals along the conveyor belt. At each unit, the tension in the conveyor belt is relieved and the maximum is therefore drastically reduced by controlling the driving torque with the control device.

Each driving unit may be controlled by an individual controller that receives control signals from the central control device for adjusting the conveyors speed ramping and load control during continuous operation. Further an independent control of each driving unit may be required for maintenance purposes when a driving unit is mechanically decoupled from the conveyor system. The actual material load along the conveyor belt is measured by the load determination device. The load determination device is positioned specifically after the loading hopper.

The control device controls the multidrive driving units such that they have always to operate together which means all driving units have to start and stop in the same way to prevent undesired forces into the conveyor belt and drive components. All driving units receive the control commands from the control device to enable, start and stop the driving units. The speed setpoint may be send to each driving unit. The belt scale near the feeding station determines the actual load. According to the actual conveyor speed (measured e.g. by the driving units or a speedometer on the conveyor belt or on the pulleys) the load along the conveyor belt is determined. The required driving torque for each driving unit to maintain the conveyor belt will be evaluated on the basis on the information of the belt scale load information. Accordingly, also a conveyor speed adjustment during normal operation can be provided. The conveyor belt speed can be selected depending on the load on the conveyor belt. The speed must be carefully adapted to the flow rate of the material fed onto the conveyor belt in the feeding section to avoid overfilling and blocking of the conveyor belt. A speed change must be in a smooth and ramped manner to avoid oscillation and fluctuation in the speed and torque control which causes stress in the conveyor belt.

It has to be noted that embodiments of the invention have been described with reference to different subject matters. In particular, some embodiments have been described with reference to apparatus type claims whereas other embodiments have been described with reference to method type claims. However, a person skilled in the art will gather from the above and the following description that, unless other notified, in addition to any combination of features belonging to one type of subject matter also any combination between features relating to different subject matters, in particular between features of the apparatus type claims and features of the method type claims is considered as to be disclosed with this application.

Brief Description of the Drawings

The aspects defined above and further aspects of the present invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment. The invention will be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

Fig. 1 shows a schematical view of a conveyor system according to an exemplar embodiment of the present invention.

Fig. 2 shows a schematical view of a conveyor system comprising an inclination and declination section according to an exemplar embodiment of the present invention.

Fig. 3 shows a schematical view of a driving unit according to an exemplar embodiment of the present invention.

Fig. 4 shows a schematical view of a load determination device being a belt scale device according to an exemplar embodiment of the present invention. Detailed Description of Exemplary Embodiments

The illustrations in the drawings are schematic. It is noted that in different figures similar or identical elements are provided with the same reference signs.

Fig. 1 shows a schematical view of a conveyor system 100 according to an exemplar embodiment of the present invention. The conveyor system 100 comprises a conveyor belt 102 comprising a conveyor surface, onto which the material 101 to be conveyed are placeable, wherein the conveyor belt 102 is movable along a conveying direction 103 between a feeding station 104, at which the material is placeable, and a removing station 105, form which the material 101 is removable from the conveyor surface.

The conveying system 100 further comprises a load determination device 106, coupled to the conveyor belt 102 for determining the actual load acting onto the conveyor belt 102 at the location of the load determination device. Furthermore, the conveying system 100 further comprises a driving unit 110 for driving the conveyor belt 102, wherein the driving unit is coupled to the conveyor belt in conveying direction after the load determination device 106.

Furthermore, the conveying system comprises a control device 107 coupled with the load determination device 106 and the driving unit 110, wherein the control device 107 is configured for controlling the driving unit 110 in such a way that a predetermined driving torque is generatable and transferrable by the driving unit 110 to the conveyor belt 102. The control device 107 is further configured determine on the basis of the speed of the conveyor belt 102, the distance between the location of the load determination device or the driving unit 110 and the further subsequent driving unit 110 along the conveying direction 103, the load acting onto the conveyor belt 102 between the driving unit 110 and the further subsequent driving unit 110 and to determine the required driving torque Mn of the further subsequent driving unit 110 for driving the conveyor belt 102 on the basis of the load between the driving unit 110 and the subsequent further subsequent driving unit 110.

The conveying system comprises a conveyor belt 102. A conveying profile, such as for example a profiled surface, a conveyor surface in the style of an elevator conveyor or other carrying elements for carrying the conveyed material 101, can be arranged on the conveyor surface of the conveyor belt

102. The conveyor belt 102 is movable along a conveying direction 103. The conveyor belt 102 forms a closed loop, wherein the feeding station 104 comprises a feeding pulley 108 and the removing station 105 comprises a removing pulley 109. The conveyor belt 102 is wound around the feeding pulley 108 and the removing pulley 109.

The material 101 is conveyed along the conveying direction 103 between a feeding station 104 and a removing station 105, wherein the conveyor belt 102 is deflected e.g. by a feeding pulley 108 or removing pulley 109 at the feeding station 104 and the removing station 105. Furthermore, at the feeding station 104 a loading hopper 112 may be arranged for filling the material 101, e.g. bulk material, to the conveyor belt 102.

A plurality of driving units 110 are arranged along the conveying direction

103. As illustrated in further detail in Fig. 3, a driving unit 110 comprises for example a driving pulley (conveying drive 303) generating the driving torque Mn. The driving unit 110 may be electrically driven. The plurality of driving units 110 are arranged one after another along the conveyor belt 102 for transferring driving torque Mn to the driving belt 304.

The driving unit 110 generates a driving torque in order to thereby drive the conveyor belt 102. The driving torque Mn can on the one hand be used to drive the conveyor belt 102, in particular in case of a certain slope or inclination sections I of the driving belt 304, where the material 101 is conveyed from a lower feeding station 104 to a higher removing station 105.

The load determination device 106 is coupled to the conveyor belt 102 specifically in or in the vicinity to the feeding station 104. The load determination device 106 measures the weight of the material 101 at the time point, when the material 101 passes the location of the load determination device. Hence, it is known under consideration of the speed of the conveyor belt 102, which weight of material 101 is arranged onto a certain section of the conveyor belt 102.

The control device 107 is coupled to the load determination device 106 for receiving the weight information and hence receives the information (e.g. by consideration of the speed of the conveyor belt 102) which section of the conveyor belt 102 carries a material 101 of a defined and measured weight. Furthermore, the control device 107 is coupled to the driving units 110. The control device 107 is configured for controlling the driving unit 110 and hence controlling the driving torques Mnl, Mn2 generated by the driving units 110 and transferred to the conveyor belt 102 at the location, where the respective driving unit 110 is coupled to the conveyor belt 102.

Additionally, the control device 107 is coupled to a respective speed sensor 113 arranged at the conveyor belt 102 for determining the actual speed of the conveyor belt 102 along the conveying direction 103.

Hence, the control device 107 receives as an input parameter the respective weight (e.g. in tons t) of material 101 at specific locations onto the conveyor belt 102 and receives as an input parameter the actual speed (m/s) and/or the setpoint speed of the conveyor belt 102. Additionally, the control device 107 receives as an input parameter the location of the load determination device 106 and the location of the plurality of driving units 110 along the conveying direction 103. Accordingly, the control device 107 is aware of the distance between the load determination device 106 and the respective driving units 110 along the conveying direction 103.

Hence, based on the input parameters, the control device 107 determines, at which time point the currently weighted material 101 at the load determination device 106 reaches the respective driving unit 110. Hence, the control device 107 determines a required and necessary driving torque (Nm) for the driving units 110 for the loads acting onto specific sections of the conveyor belt 102 such that the required driving torque Mnl, Mn2 drives the conveyor belt 102 with a predefined speed and that the driving torque Mnl, Mn2 does not exceed for example a critical maximum driving torque Mn which could damage the conveyor belt 102.

The control device 107 determines on the basis of the speed of the conveyor belt 102 and on the basis of the location of the further driving unit 110 the load acting on the conveyor belt 102 along a section between the further driving unit 110 and e.g. to a previous driving unit 110, a subsequent driving unit 110 or to the load determination device 106. Based on this information, the control device 107 regulates the required further driving torque Mn2 at the further driving unit 110.

The control device 107 adjusts the required driving torque Mnl of the driving unit 110 independently with respect to the required further driving torque of the further driving torque Mn2. Hence, the control device 107 controls the driving units 110 independent from each other such that each driving unit 110 transfers and generates the respective driving torque Mnl that is adapted to the load acting onto the conveyor belt 102 specifically between the load determination device 1006 and a respective driving unit 110 or between two adjacent driving units 110. For example, based on the load acting on the conveyor belt 102 when passing the one driving unit 110, the generated driving torque Mnl may be higher with respect to a driving torque Mn2 of another driving unit 110, where at the moment the load of the conveyor belt 102 is lower such that less driving torque Mn2 is necessary for driving the conveyor belt 102.

Alternatively, based on the load acting on the conveyor belt 102 specifically between the load determination device and a respective driving unit or between two adjacent driving units, the generated driving torque Mnl may be reduced with respect to a driving torque Mn2 of another driving unit 110, where at the moment the load of the conveyor belt 102 is lower such that a higher driving torque Mn2 can be applied for driving the conveyor belt 102 without exceeding a critical maximum load of the conveyor belt 102.

As shown in the embodiment in Fig. 1, the conveyor belt 102 comprises an inclination section I having a determined inclination, wherein the material 101 is lifted along the conveying direction 103. The driving unit 110 is coupled to the conveyor belt 102 at the inclination section I, wherein the control device 107 determines the required driving torque Mn additionally on the basis of the inclination of the conveyor belt 102 at the location of the driving unit 110.

At inclined regions of the conveyor belt 102, the load acting on the conveyor belts 102 by the weight of the material 101 is higher than at horizontal regions of the conveyor belt 102, since the conveyor belt 102 must additionally lift the material 101 along a vertical component. The control device 107 considers the inclination of the conveyor belt 102 at the location where the driving unit 110 is coupled to the conveyor belt 102 such that either an increased driving torque Mn is generated or a reduced driving torque Mn is generated for reducing the loads acting on the conveyor belt 102 due to the inclination. In the embodiment shown in Fig. 1, the feeding station 104 is located at a lower level than the removing station 105. Hence, the conveyor system 100 is designed for lifting the material 101.

Dependent on the load acting on the conveyor belt 102 specifically between the load determination device 106 and a respective driving unit 110 or between two adjacent driving units 110, a customized and specific driving torque Mn is adjusted for each driving unit 110 such that a constant speed of the conveyor belt 102 along the whole conveying direction 103 can be adjusted. Furthermore, the control device 107 is configured to adjust the required driving torque Mn dependent on the load specifically between the load determination device 106 and a respective driving unit 110 or between two adjacent driving units 110 for increasing or decreasing the speed of the conveyor belt 102. Hence, specifically if the conveyor belt 102 is started or stopped, as a target for the driving units 110, the increasing or decreasing of the speed may be defined. Based on the respective load acting onto the driving units 110, a respective required and individual driving torque Mnl, Mn2 for each driving unit 110 is determined in order to provide a smooth acceleration or deceleration of the conveyor belt 102.

The feeding pulley 108 and the removing pulley 109 is free of driving means and rotatable by the movement of the conveyor belt 102. At least one of the feeding pulley 108 and the removing pulley 109 is adjustable for tensioning the conveyor belt 102. Hence, the tension of the conveyor belt 102 may be adjusted particular with respect to the overall load acting onto the conveyor belt 102 due to the weight of the material 101 to be transported.

Fig. 2 shows a conveyor system 100 showing all features of the embodiment shown in Fig. 1 but comprising an inclination section I and a declination section II according to an exemplar embodiment of the present invention. As shown, the feeding station 104 is located at a higher level than the removing station 105. However, in alternative embodiments, the conveyor system may comprise a plurality of inclination sections I and/or declination sections II.

The declination section II has a determined declination, wherein the material 101 is lowered along the conveying direction 103. The driving units 110 are coupled to the conveyor belt 102 at the declination section II. The control device 107 determines the required driving torque Mn3 additionally on the basis of the declination of the conveyor belt 102 at the location of the driving unit 110. Hence, the control device 107 considers the declination of the conveyor belt 102 at the location where the driving unit 110 is coupled to the conveyor belt 102 such that either an increased driving torque is generated or a reduced driving torque is generated for reducing the loads acting on the conveyor belt 102 due to the inclination. Specifically, the control device 107 reduces the driving torque in a respective declination section II, since due to the weight of the material 101 specifically between the load determination device 106 and a respective driving unit 110 or between two adjacent driving units 110 , a slope downforce is generated by the weight of the material 101 such that the driving torque of the driving unit 110 has to be adapted and reduced, respectively. The driving unit 110 may generate a driving torque Mn3 acting in counter direction with respect to the conveying direction 103 such that the driving unit 110 acts as a brake for the conveyor belt 102.

Hence, the driving torque Mn3 can also be utilized as a braking force. The driving unit 110 is thus utilized as a brake which counteracts the movement of the conveyor belt 102. Thus, the driving torque may be a negative driving torque for applying a braking moment. For example, it is necessary that the conveyor belt 102 is braked when a material 101 is transported from a higher feeding station 104 to a lower removing station 105, in order to keep the speed of the conveyor belt 102 constant or to reduce it. Fig. 3 shows a schematical view of a driving unit 110 according to an exemplar embodiment of the present invention.

A driving unit 110 comprises for example a driving pulley (conveying drive 303) generating the driving torque Mn. The conveying drive 303 is pressed or engaged by a coupling profile 301, 302 directly or via a driving belt 304 with the conveyor belt 102 such that upon rotation of the conveying drive 303, the respective driving torque Mn for driving the conveyor belt 102 can be transferred. As described in an exemplary embodiment below, between the conveyor belt 102 and the conveying drive 303, the respective drive belt 304 is interposed.

The conveyor belt 102 comprises a coupling surface comprising a first coupling profile 301, wherein the driving unit 110 comprises at least one conveying drive 303 for transmitting driving torque Mn to the conveyor belt 102 for driving and/or braking the conveyor belt 102. The conveying drive 303 comprises a second coupling profile 302, wherein the first coupling profile 301 is coupled with the second coupling profile 302 in such a way that the conveying drive 303 is coupled with the conveyor belt 102 in an interlocking manner for transferring driving torque.

The conveyor belt 102 further forms the first coupling profile 301 which engages in an interlocking coupling by means of a second coupling profile 302 of the conveying drive 303. The first coupling profile 301 and the corresponding second coupling profile 302 can for example comprise a corresponding toothed profile. The first coupling profile 301 or the second coupling profile 302 can further comprise other engaging structures, such as for example a rod element, which extends transverse to a conveying direction of the conveyor belt 102. The first coupling profile 301 may be formed along the entire length of the conveyor belt 102. The first coupling profile 301 can for example be releasably or detachably fastened to the conveyor belt 102, for example by means of a screw connection.

The conveying drive 303 serves to generate the driving torque Mn in order to thereby drive the conveyor belt 102. For the force coupling, the first coupling profile 301 is coupled to the second coupling profile 302 in an interlocking manner, in order to thereby cause a precise and robust force transmission to the conveyor belt 102. The driving torque Mn can on the one hand be utilized as a driving force in order to drive the conveyor belt 102, in particular in case of a certain slope or inclination, where the material 101 is to be conveyed from a lower starting point to a higher ending point.

The driving belt 304 forms a closed loop which is guided around two circulating rollers 303, 305 which are spaced apart from each other. When using the driving belt 304, the driving torque Mn is not transmitted punctually or in a point by point manner but instead along an elongated coupling portion. Thereby, the driving torque Mn can be gently transmitted as no punctual force peaks occur when the driving torque Mn is transmitted. The rotational axes of the circulating rollers 303, 305 are arranged on a common central axis. At least one of the circulating rollers 303 can be formed as a drive drum or a drive roller. These apply the driving torque Mn, for example as a driving force or a braking force, and transmit it to the driving belt 304.

The conveying system 100 comprises a tensioning device 306 for adjusting the distance between the circulating rollers 303, 305 for tensioning the driving belt with a pretensioning force Fv. The circulating rollers 303, 305 may be mounted to a common supporting frame, wherein one of the circulating rollers 305 may be movably coupled to the supporting frame in order to be movable to and away from the other drivable circulating roller 303. Thereby, a predetermined pre-tensioning force Fv of the driving belt 304 is adjusted depending on the distance of the circulating rollers 303, 305. The tensioning device 306 is in the example a spindle drive for moving the circulating roller 305 along the supporting frame in order to tensioning the driving belt 304. Depending on the load acting on a certain load section, for example between the load detection unit 106 and the driving unit 110 or between further driving units 10, the respective tensioning of the driving belt 304 is to be adjusted in order to transmit effectively the driving torque Mn to the conveyor belt 102.

The control device 107 is configured for controlling the tensioning device 306 for tensioning the driving belt 102 on the basis of the driving torque Mn of the driving unit 110 for driving the conveyor belt 102 on the basis of the load between the location of the load determination device 106 and the driving unit 110.

Fig. 4 shows a schematical view of a load determination device 106 forming a belt scale device according to an exemplar embodiment of the present invention. The load determination device 106 comprises belt carrier roller 401 onto which the conveyor belt 102 may be located. The weight force and hence the load may be transferred via the belt carrier rollers 401 to a carrier frame 402. The carrier frame 402 supports the belt carrier rollers 401. Between the belt carrier rollers 401 and the carrier frame 402, weight sensors may be installed to measure the respective load.

It should be noted that the term "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined. It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims. List of reference signs:

100 conveyor system

101 conveying material

102 conveyor belt

103 conveying direction

104 feeding station

105 removing station

106 load determination device

107 control device

108 feeding pulley

109 removing pulley

110 driving unit

111 guiding pulley

112 loading hopper

113 speed sensor

301 first coupling profile

302 second coupling profile

303 conveying drive

304 driving belt

305 circulating rollers

306 tensioning device

401 belt carrier roller

402 carrier frame

I inclination section

II declination section

Mn driving torque

Fv pretensioning force

Claims

CLAIMS:

1. Conveyor system (100) for conveying material (101), the conveyor system (100) comprising a conveyor belt (102) comprising a conveyor surface, onto which the material (101) to be conveyed are placeable, wherein the conveyor belt (102) is movable along a conveying direction (103) between a feeding station (104), at which the material (101) is placeable, and a removing station (105), form which the material (101) is removable from the conveyor surface, a load determination device (106), coupled to the conveyor belt (102) for determining the actual load acting onto the conveyor belt (102) at the location of the load determination device (106), a driving unit (110) for driving the conveyor belt (102), wherein the driving unit (110) is coupled to the conveyor belt in conveying direction (103) after the load determination device (106), a control device (107) coupled with the load determination device (106) and the driving unit (110), wherein the control device (107) is configured for controlling the driving unit (110) in such a way that a predetermined driving torque (Mn) is generatable and transferrable by the driving unit (110) to the conveyor belt (102), wherein the control device (107) is further configured to determine on the basis of the speed of the conveyor belt (102) and the distance between the location of the load determination device and the driving unit (110) along the conveying direction (103) the load acting onto the conveyor belt (102) between the location of the load determination device and the driving unit (110) and to determine the required driving torque (Mn) of the driving unit (110) for driving the conveyor belt (102) on the basis of the load between the location of the load determination device and the driving unit (110).

2. Conveyor system (100) according to claim 1, further comprising a further subsequent driving unit (110) for driving the conveyor belt (102), wherein the further driving unit (110) is coupled to the conveyor belt in conveying direction (103) after the driving unit (110), wherein the control device (107) is further coupled with the subsequent further driving unit (110) in such a way that a further predetermined driving torque (Mn) is generatable and transferrable by the further driving unit (110) to the conveyor belt (102), wherein the control device (107) is further configured to determine on the basis of the speed of the conveyor belt (102), the distance between the location of the load determination device or the driving unit (110) and the further subsequent driving unit (110) along the conveying direction (103), the load acting onto the conveyor belt (102) between the driving unit (110) and the further subsequent driving unit (110) and to determine the required driving torque (Mn) of the further subsequent driving unit (110) for driving the conveyor belt (102) on the basis of the load between the driving unit (110) and the subsequent further subsequent driving unit (110).

3. Conveyor system (100) according to claim 2, wherein the control device (107) is further configured to adjust the required driving torque (Mn) of the driving unit (110) independently with respect to the required further driving torque (Mn) of the further driving unit (110).

4. Conveyor system (100) according to claim 2 or 3, wherein at least one of the driving unit (110) and the further driving unit (110) is selectively decouplable from the conveyor belt (102).

5. Conveyor system (100) according to one of the claims 1 to 4, wherein the conveyor belt (102) comprises an inclination section (I) having a determined inclination, wherein the material (101) is lifted along the conveying direction (103), wherein the driving unit (110) is coupled to the conveyor belt (102) at the inclination section (I), wherein the control device (107) determines the required driving torque additionally on the basis of the inclination of the conveyor belt (102) along the inclination section (I).

6. Conveyor system (100) according to one of the claims 1 to 5, wherein the conveyor belt (102) comprises a declination section (II) having a determined declination, wherein the material (101) is lowered along the conveying direction (103), wherein the driving unit (110) is coupled to the conveyor belt (102) at the declination section (II), wherein the control device (107) determines the required driving torque additionally on the basis of the declination of the conveyor belt (102) along the declination section (II).

7. Conveyor system (100) according to one of the claims 1 to 6, wherein the feeding station (104) is located at a lower level than the removing station (105).

8. Conveyor system (100) according to one of the claims 1 to 7, wherein the feeding station (104) is located at a higher level than the removing station (105).

9. Conveyor system (100) according to one of the claims 1 to 8, wherein the control device is configured to adjust the required driving torque (Mn) dependent on the load acting on the conveyor belt (102) between the location of the load determination device and the driving unit (110) for keeping the speed of the conveyor belt (102) constant.

10. Conveyor system (100) according to one of the claims 1 to 9, wherein the control device is configured to adjust the required driving torque (Mn) dependent on the load acting on the conveyor belt (102) between the location of the load determination device and the driving unit (110) for increasing or decreasing the speed of the conveyor belt (102).

11. Conveyor system (100) according to one of the claims 1 to 10, wherein the conveyor belt (102) forms a closed loop, wherein the feeding station (104) comprises a feeding pulley (108) and the removing station (105) comprises a removing pulley (109), wherein the conveyor belt is wound around the feeding pulley (108) and the removing pulley (109).

12. Conveyor system (100) according to claim 11, wherein at least one of the feeding pulley (108) and the removing pulley (109) is free of driving means and rotatable by the movement of the conveyor belt (102).

13. Conveyor system (100) according to claim 12, wherein at least one of the feeding pulley (108) and the removing pulley (109) is adjustable for tensioning the conveyor belt.

14. Conveyor system (100) according to one of the claims 1 to 13, wherein the control device is configured to adjust the speed of the conveyor belt (102) within a predetermined maximum driving torque (Mn).

15. Conveyor system (100) according to one of the claims 2 and 14, wherein the control device is configured to increase the further driving torque (Mn) of the further driving unit (110) if the driving torque (Mn) of the driving unit (110) reaches the maximum driving torque (Mn) range.

16. Conveyor system (100) according to one of the claims 1 to 15, wherein the conveyor belt (102) comprises a coupling surface comprising a first coupling profile (301), wherein the driving unit (110) comprises a driving belt (304) having a second coupling profile (302), wherein a part of the second coupling profile (302) of the driving belt (304) extends parallel to the coupling surface of the conveyor belt (102) in such a way that the first coupling profile (301) engages with the second coupling profile (302) in an interlocking manner along the coupling portion of the conveyor belt (102), wherein in particular at least one of the first coupling profile (301) and the second coupling profile is formed as a toothed belt profile.

17. Conveyor system (100) according to claim 16, wherein the driving belt (304) forms a closed loop which is guided around two circulating rollers (303, 305) which are spaced apart from each other, wherein in particular one of the circulating rollers (303, 305) is a driven roller forming a conveying drive (303).

18. The conveying system according to claim 17, further comprising a tensioning device (306) for adjusting the distance between the circulating rollers (303, 305) for tensioning the driving belt (304).

19. The conveying system according to claim 18, wherein the control device (107) is configured for controlling the tensioning device (306) for tensioning the driving belt (304) on the basis of the driving torque (Mn) of the driving unit (110) for driving the conveyor belt (102) on the basis of the load between the location of the load determination device (106) and the driving unit (110).

20. Method for controlling a conveyor system (100) for conveying material (101), the method comprising placing material (101) to be conveyed into a conveyor surface of a conveyor belt (102), wherein the conveyor belt (102) is movable along a conveying direction (103) between a feeding station (104), at which the material (101) is placeable, and a removing station (105), form which the material (101) is removable from the conveyor surface, determining an actual load acting onto the conveyor belt (102) at a location of the load determination device by a load determination device (106) coupled to the conveyor belt (102), driving the conveyor belt (102) by a driving unit (110), wherein the driving unit (110) is coupled to the conveyor belt in conveying direction (103) after the load determination device (106), controlling the driving unit (110) by a control device (107), which is coupled with the load determination device (106) and the driving unit (110), in such a way that a predetermined driving torque (Mn) is generatable and transferrable by the driving unit (110) to the conveyor belt (102), and controlling the driving unit (110) by the control device (107) in such a way that a predetermined driving torque (Mn) is generatable and transferrable by the driving unit (110) to the conveyor belt (102), determining by the control device (107) on the basis of the speed of the conveyor belt (102) and the distance between the location of the load determination device and the driving unit (110) along the conveying direction (103), the load acting onto the conveyor belt (102) between the location of the load determination device and the driving unit (110) and to determine the required driving torque (Mn) of the driving unit (110) for driving the conveyor belt (102) on the basis of the load between the location of the load determination device and the driving unit (110).