阅读说明：本技术 用于监测采矿机器单元的操作的方法和装置 (Method and device for monitoring the operation of a mining machine unit ) 是由 E·基尔克霍普 J·瓦色尔曼 于 2020-03-02 设计创作，主要内容包括：本发明涉及一种用于监测采矿机器单元(30)、特别是长壁采矿系统(10)的操作的方法,所述采矿机器单元具有借助于致动器(36)连接到材料移除单元(12)的护罩单元(32),所述致动器用于调节所述护罩单元(32)与所述材料移除单元(12)之间的距离,所述方法包括：在所述致动器(36)的致动操作期间确定所述护罩单元(32)的位置变化的步骤；以及基于所述确定的位置变化来检测所述采矿机器单元(30)的故障的步骤。(The invention relates to a method for monitoring the operation of a mining machine unit (30), in particular a longwall mining system (10), having a shroud unit (32) connected to a material removal unit (12) by means of an actuator (36) for adjusting the distance between the shroud unit (32) and the material removal unit (12), the method comprising: a step of determining a change in position of the shield unit (32) during an actuating operation of the actuator (36); and a step of detecting a malfunction of the mining machine unit (30) based on the determined change in position.)

1. A method for monitoring the operation of a mining machine unit (30), in particular a longwall mining system (10), having a shroud unit (32) connected to a material removal unit (12) by means of an actuator (36) for adjusting the distance between the shroud unit (32) and the material removal unit (12), the method comprising the steps of:

-determining a change in position of the shield unit (32) during an actuation operation of the actuator (36); and

-detecting a malfunction of the mining machine unit (30) based on the determined change in position.

2. The method of claim 1, wherein the actuation operation is a retraction operation of the actuator (36).

3. Method according to claim 1 or 2, wherein the determined change in position is indicative of a displacement length of the shield unit (32), in particular relative to an initial position of the shield unit (32).

4. A method according to any of claims 1-3, wherein the change in position is indicative of a change in position of the shield unit in a direction (X) directed towards the material removal unit (12).

5. The method according to any one of claims 1 to 4, wherein the change in position is determined by means of a change in position sensor (62) configured to determine a change in at least one of the position of the shroud unit relative to an initial position of the shroud unit (32), the material removal unit (12), a further mining machine unit arranged adjacent to the mining machine unit (30), and the surroundings of the mining machine unit (30).

6. The method according to any one of claims 1 to 5, wherein the change in position is determined by means of an acceleration sensor (62).

7. The method according to any of claims 1 to 6, wherein in the step of detecting a fault, a failure state of the mining machine unit (30) is detected when the determined change in position does not indicate a change in position of the shroud unit, and wherein a suitable state of the mining machine unit (30) is detected when the determined change in position indicates a change in position of the shroud unit.

8. The method according to any one of claims 1 to 7, wherein in the step of detecting a fault, a failure condition of the mining machine unit (30) is detected when the determined change in position does not exceed a threshold value, and wherein a suitable condition of the mining machine unit (30) is detected when the determined change in position equals or exceeds the threshold value.

9. The method according to any one of claims 1 to 8, further comprising the step of determining a stroke variation of the actuator (36) during its actuation operation, wherein the step of detecting a malfunction of the mining machine unit (30) is performed based on the determined stroke variation.

10. Method according to claim 9, wherein the determined stroke change is indicative of a stroke change length, in particular with respect to an initial stroke of the actuator (36) before being operated in an actuation operation thereof.

11. The method according to claim 9 or 10, wherein in the step of detecting a fault, a failure condition of the mining machine unit (30) is detected when the determined stroke variation is not correlated with the determined position variation, and wherein a suitable condition of the mining machine unit (30) is detected when the determined stroke variation is correlated with the determined position variation.

12. The method of any of claims 9-11, wherein the failure condition is detected when an absolute value of the determined stroke change is greater than a first threshold or when an absolute value of the determined position change is less than a second threshold, and wherein

Detecting the appropriate state when the absolute value of the determined stroke change is equal to or greater than the first threshold and the absolute value of the determined position change is equal to or greater than the second threshold.

13. The method of claim 12, wherein the second threshold is determined based on the determined stroke change.

14. The method according to any one of claims 1 to 13, wherein the actuator (36) is connected to at least one of the shroud unit (32) and the material removal unit (12) by means of a shear pin (46) configured to release the connection between the actuator (36) and at least one of the shroud unit (32) and the material removal unit (12) when a machine force acting on the shear pin (46) exceeds a predetermined value.

15. The method according to any one of claims 1 to 10, wherein the actuator (36) is a linear actuator, in particular a telescopic actuator comprising a cylinder (38) fastened to the shroud unit (32) and a piston (30) fastened to the material removal unit (12).

16. A monitoring device (60) for monitoring operation of a mining machine unit (30) having a shroud unit (32) connected to a material removal unit (12) by an actuator (36) configured to adjust a distance between the shroud unit (32) and the material removal unit (12), wherein the monitoring device (60) comprises:

-a sensor unit (62) for determining a change in position of the shield unit (32) during an actuation operation of the actuator (36), and

a detection unit (64) for detecting a malfunction of the mining machine unit (30) based on the determined change in position.

17. The monitoring device according to claim 16, wherein the detection unit (64) is configured to perform the method according to any one of claims 1 to 15.

18. The monitoring device according to claim 16 or 17, wherein the sensor unit (62) comprises an acceleration sensor.

19. A mining machine unit (30) for use in a longwall mining system (10) comprising a monitoring device according to any one of claims 16 to 18.

Technical Field

The invention relates to a method and a monitoring device for monitoring the operation of a mining machine unit of a longwall mining system, in particular for detecting faults.

Background

Longwall mining systems are used for underground coal mining. Such systems are configured to mine coal by cutting the earth along a broad coal face (i.e. having a width of up to 400 m). To this end, as the longwall mining system is continuously propelled underground, coal along the coal face is removed in layers while the roof and overburden collapse into the void created behind the propelled longwall mining system during operation.

In order to prevent collapsed material and thus maintain a safe working space along and in front of the coal face, such longwall mining systems typically include a plurality of powered roof supports arranged side-by-side in the longline side in front of the coal face. The roof supports are configured for selectively supporting a roof covering a longwall mining system and are also referred to as shroud units. Furthermore, the roof supports are usually equipped with translationally actuatable relay rods via which they are connected to the armored face conveyor.

An armored face conveyor extends along the coal face and carries a shearer unit having rotatably actuated cutting drums for cutting coal from the coal face. The shearer unit is supported translationally on the armored face conveyor to drive the cutting drums back and forth along the coal face to remove and fragment coal from the coal face loaded on the armored face conveyor. The armored face conveyor then conveys the removed coal to one side of the longwall mining system, where it is further loaded onto a network of conveyor belts for transport to the ground.

The operation of such a longwall mining system is explained below. First, a longwall mining system is positioned in front of the coal face to enable removal of coal from the coal face by means of a shearer unit. The shearer unit is actuated and translated along the entire width of the armored face conveyor to remove and ablate a complete coal seam from the coal face. During a cutting operation of the shearer unit, the powered roof supports operate in a joined mode in which the powered roof supports or consolidates the roof above the longwall mining system.

Then, after removing the coal seam, the armored face conveyor is moved with the shearer unit toward the coal face to re-engage the cutting drums of the shearer unit with the coal face. This is performed by means of a powered roof support. More specifically, in the engaged mode of the roof supports, the relay rods are actuated to project, thereby pushing the armored face conveyor with the shearer unit toward the coal face.

Thereafter, the roof supports are individually and continuously moved to access the armored face conveyor. For this reason, the respective ceiling stay to be moved is released so that the supporting force is not applied to the ceiling any more. In this released state, the roof supports are then pulled towards the displaced armored face conveyor by the retraction actuation of the relay rods. In this way, the individual roof supports are moved to follow the armored face conveyor. This is performed successively for each roof support.

As a result, the longwall mining system is made to travel in the feed direction by repeatedly pushing the armored face conveyor one after the other, and then pulling the roof supports to follow the movement of the armored face conveyor.

Typically, the relay rod of the roof support is secured to the armored face conveyor by means of shear pins. The shear pins are configured to release the connection between the relay rod and the armored face conveyor when a machine force acting on the individual shear pins exceeds a predetermined value. In this way, the shear pin protects the connectors and components of the longwall mining system from excessive forces.

However, if the connection between the individual roof supports and the armored face conveyor is released, the roof supports can no longer be moved or pulled in the direction of movement of the longwall mining system to follow the armored face conveyor. Thus, when the other roof supports travel with the armored face conveyor, the roof supports may be left behind. This can lead to serious drawbacks of longwall mining systems. For example, in this case, the hydraulic connections arranged along and between the roof supports may be torn open. Furthermore, roof supports left behind may be damaged by collapsed roof in voids behind the longwall mining system.

Disclosure of Invention

It is therefore an object to provide a robust method and monitoring device for detecting a failure of a mining machine unit, in particular a longwall mining system. Furthermore, it is an object of the invention to provide a mining machine unit for use in a longwall mining system equipped with such a monitoring device.

This is solved by a method, a monitoring device and a mining machine unit for use in a longwall mining system according to the independent claims. Preferred embodiments are set forth in the description, drawings and dependent claims.

Accordingly, a method for monitoring the operation of a mining machine unit, in particular a longwall mining system, is provided. The mining machine unit to be monitored comprises a shield unit, which is connected to the material removal unit by means of an actuator for adjusting the distance between the shield unit and the material removal unit. The method comprises the following steps: determining a change in position of the shroud unit during an actuation operation of the actuator; and detecting a fault of the mining machine unit based on the determined change in position.

Furthermore, a monitoring device for monitoring the operation of a mining machine unit is provided. The mining machine unit comprises a shield unit connected to the material removal unit by an actuator configured for adjusting a distance between the shield unit and the material removal unit. In particular, the monitoring device comprises a sensor unit for determining a change in position of the shroud unit during an actuation operation of the actuator and a detection unit for detecting a malfunction of the mining machine unit based on the determined change in position.

To this end, a mining machine unit for use in a longwall mining system is provided, the mining machine unit being equipped with the above-mentioned monitoring device.

Drawings

The invention will be more readily understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

fig. 1 schematically shows a perspective view of a longwall mining system comprising a plurality of mining machine units;

fig. 2 schematically shows a perspective view of a connection between a mining machine unit and a material removal device of the longwall mining system depicted in fig. 1;

fig. 3 schematically shows a side view of the mining machine unit depicted in fig. 1 and 2, the mining machine unit being equipped with a monitoring device for monitoring the operation of the mining machine unit;

fig. 4 shows a flow chart illustrating a method performed by the monitoring device depicted in fig. 3 for monitoring the operation of a mining machine unit;

FIG. 5 shows a graph illustrating the measurement signals obtained by the sensor unit of the monitoring device depicted in FIG. 3; and

fig. 6 schematically shows a bottom view of a connection between a mining machine unit and a material removal unit equipped with a monitoring device according to another embodiment.

Detailed Description

Hereinafter, the present invention will be explained in more detail with reference to the accompanying drawings. In the drawings, the same elements are denoted by the same reference numerals, and repetitive description thereof may be omitted in order to avoid redundancy.

Fig. 1 depicts a longwall mining system 10 intended for underground mining (i.e., longwall mining). In particular, the illustrated longwall mining system 10 may be used for coal mining, but is not limited to such applications. Instead, the longwall mining system 10 may be used for the mining of other materials, i.e., underground mining.

The longwall mining system 10 includes a material removal unit 12 configured to be placed in front of a coal face to be processed by the longwall mining system 10. In particular, the material removal unit 12 includes an armored face conveyor 14 provided in the form of a long line configured for placement along the entire width of the coal face. The material removal unit 12 further includes a shearer unit 16 that is supported translationally on the armored face conveyor 14.

The shearer unit 16 includes a carriage 18 or body that engages with a track system 20 of the armored face conveyor 14 by means of a traction power unit 22 configured for driving the shearer unit 16 along the track system 20. With this arrangement, the shearing unit 16 is configured to move along the armored face conveyor 14 and thus along the coal face.

At the opposite end of the carriage 18, the shearer unit 16 is provided with a ranging arm 24 that is configured to be moved up and down by a hydraulic ram 26. Each rocker arm 24 carries a shearer cutting drum 28, the shearer cutting drum 28 having a plurality of cutting bits mounted on a circumferential surface thereof. The shearer cutting drum 28 is rotationally driven and configured to remove and break down coal as it is fed along the coal face.

The armored face conveyor 14 is configured to receive coal removed from the coal face during cutting operations of the shearer unit 16 and convey the removed coal to a side of the longwall mining system 10 where it may be loaded onto a network of conveyor belts for transport to the ground.

The longwall mining system 10 further includes a plurality of mining machine units 30 arranged side-by-side in long lines behind and along the armored face conveyor 14. In this context, the term "rear" refers to the direction of movement or feed of the longwall mining system 10.

Each mining machine unit 30 includes a shroud unit 32, also referred to as a roof support, or jack unit. The shroud unit 32 is configured to selectively support a roof covering the longwall mining system 10 when operating in the ground. To this end, the shroud unit 32 includes a hydraulically actuated shroud 34 that is movable up and down.

Shroud unit 32 is configured for operation in a joining mode of operation in which shroud 34 supports a top plate that covers shroud unit 32. In the engaged mode, the shroud 34 moves upward. Furthermore, the shield unit 32 may be operated in a release mode of operation in which the shield 34 is moved downwardly compared to its engagement mode of operation.

As shown in fig. 2, each shroud unit 32 is connected to the material removal unit 12 by an actuator 36. Each actuator 36 is configured to adjust the distance between the corresponding shroud unit 32 and the material removal unit 12.

Specifically, the actuator 36 is a linear actuator provided in the form of a telescopic actuator that includes a cylinder 38 and a piston 40, also referred to as a relay rod or ram. The actuator 36 is arranged such that, upon actuation thereof, the piston 40 moves, i.e. retracts or extends, relative to the cylinder 38 in the feed direction X of the longwall mining system 10.

In the illustrated configuration, each actuator 36 is arranged such that the cylinder 38 is secured directly to the body of the corresponding shroud unit 32 and the piston 40 is secured directly to the armored face conveyor 14. Alternatively, the actuator 36 may be arranged such that the piston 40 is fastened directly to the body of the shroud unit 32 and the cylinder 38 is fastened directly to the armored face conveyor 14. Each actuator 36 is associated with and connected to a respective section of the armored face conveyor 14. These portions are also referred to as disks 44.

The piston 40 of each actuator 36 is secured to a corresponding disc 44 of the armored face conveyor 14 by a shear pin 46. Specifically, each pan 44 of the armored face conveyor 14 is provided with a clevis hinge 50 to which the head 48 of the piston 40 is secured by means of the shear pin 46. As may be taken from fig. 2, each clevis hinge 50 includes a recess for receiving the head 48 of the corresponding piston 40, with the shear pin 46 extending vertically through both the clevis hinge 50 and the head 48 of the piston 40. To secure the shear pin 46 in its engaged position with the clevis hinge 50 and the piston 40, a shear pin 52 is provided.

The shear pin 46 is configured to break and thus release the connection between the actuator 36 and the material removal unit 12 when the machine force acting on the shear pin 46 exceeds a predetermined value. In this way, the shear pins 46 form a predetermined breaking point for protecting the mining machine unit 30 and the material removal unit 12 from excessive loads that may cause irreparable damage to the longwall mining system.

The clevis hinges 50 are connected to the respective discs 44 of the armored face conveyor 14 by means of bolted connections that allow the clevis hinges 50 to move vertically relative to the discs 44. The bolted connection includes a bolt 54 fixedly secured to a clevis hinge 50 that is received in a slot 56 provided in the disc 44. With such a configuration, the connection between the actuator 36 and the material removal unit 12 allows a rotational movement about an axis perpendicular to the feed direction X.

Furthermore, as shown in fig. 3, the longwall mining system 10 includes a central control unit 58 for controlling the operation of the individual mining machine units 30. In particular, the central control unit 58 is configured to selectively actuate the shroud units 32 and the actuators 36 of the plurality of mining machine units 30 to control forward movement of the longwall mining system 10 in the feed direction X. To this end, the central control unit 58 is configured to selectively operate the actuator 36 in a retraction mode of operation, in which the piston is retracted relative to the cylinder 38, and an extension mode of operation, in which the piston 38 is extended relative to the cylinder 38. Further, the central control unit 58 is configured to selectively operate the shroud units 32 in an engaging mode of operation, in which each shroud 34 moves upwardly to engage and support a roof covering each mining machine unit 30, and a releasing mode of operation, in which each shroud 34 moves downwardly. Thus, in the release mode of operation, the shroud units 32 do not engage with, and therefore do not support, the roof covering each mining machine unit 30.

In this way, the central control unit 58 is able to control the forward movement of the longwall mining system 10. In particular, in order to move the material removal unit 12 forward, i.e. in the direction of and towards the coal face, the central control unit 58 first operates the shield units 32 of the plurality of mining machine units 30 into their engaged mode of operation such that the shields 34 occupy their engaged position in which they engage and thus support the roof covering the longwall mining system 10. The actuators 36 of the plurality of mining machine units 30 are then operated in their protruding mode of operation in order to push the material removal unit 12 in the feed direction X of the longwall mining system 10. Thereafter, the central control unit 58 continuously moves each mining machine unit 30 to follow the movement of the material removal unit 12. To this end, the central control unit 58 first operates the shroud units 32 of the individual mining machine units 30 in their release mode of operation, thereby moving their shrouds 34 downwards so as to no longer engage the roof covering the mining machine units 30. Thereafter, the actuator 36 of the same mining machine unit 30 is operated in its retracted mode of operation, thereby pulling the shroud unit 32 towards the displaced material removal unit 12 so as to follow its movement. The pulling operation is successfully performed for each of the plurality of mining machine units 30. In this way, the feed motion of the longwall mining system 10 may be performed continuously.

Furthermore, in order to monitor the operation of the longwall mining system 10, each of the plurality of mining machine units 30 is equipped with a monitoring device 60. The monitoring device 60 is configured for monitoring the operation of its corresponding mining machine unit 30, i.e. for detecting a malfunction of the mining machine unit 30. In other words, the monitoring device 60 is configured to detect whether the respective mining machine unit 30, i.e. its connection to the material removal unit 12, is in a suitable state or a faulty state.

In the context of the present invention, the term "suitable state" refers to the conditions of the mining machine unit 30 that ensure proper operation of the longwall mining system 10. Thus, the term "fault" or "failure condition" refers to a status of the mining machine unit 30 that indicates that proper operation of the longwall mining system 10 cannot be ensured. Conversely, when further operation of the longwall mining system 10 is effected while one or more mining machine units 30 are affected by a fault, damage to components of the longwall mining system, i.e., the mining machine units 30, is expected.

In the illustrated configuration, each of the plurality of mining machine units 30 is equipped with a monitoring device 60, respectively. In an alternative embodiment, a common monitoring device 60 may be used to monitor the operation of a plurality of mining machine units 30. In such a configuration, at least a portion of the monitoring device 60 may be constituted by the central control unit 58.

Referring to fig. 4, a method for monitoring the operation of a mining machine unit 30 is specified, which is performed by one of the monitoring devices 60 described above. The method is exemplarily described in connection with one of the plurality of monitoring devices 60 and may thus be applied by each of the other monitoring devices 60 of the longwall mining system 10.

In a first step S1 of the method, changes in the state of the shroud unit 32 and the actuator 36 are monitored during an actuation operation of the actuator 36. The actuation operation generally refers to actuation of the actuator 36 for reducing the distance between the respective shroud unit 32 and the material removal unit 12. In other words, the actuating operation refers to an operation of the actuator 36 for pulling the shield unit 32 toward the material removal unit 12, i.e., for enabling the shield unit 32 to follow the advancing movement of the material removal unit 12, as described above. In the illustrated configuration, the actuation operation is a retraction operation and thus corresponds to operation of the actuator 36 in a retraction mode of operation.

In particular, the first step S1 includes two sub-steps that may be performed simultaneously or sequentially. In a first sub-step S1.1, a change in position Δ p of the shroud unit 32 is determined during an actuating operation of the actuator 36. Specifically, the position change Δ p refers to a parameter indicating the displacement, i.e., the length of the displacement to which the shield unit 32 is or has been subjected during the actuation operation of the actuator 36. In other words, the position change Δ p represents the displacement of the shield unit 32 from the initial position, i.e., the displacement length. More specifically, the position change Δ p represents the distance between the end position and the initial position of the shroud unit 32 during the actuation operation. In this context, the term "initial position" refers to the position of shroud unit 32 at the beginning of an actuation operation or before actuator 36 is operated in an actuation operation. The term "end position" refers to a position of shroud unit 32 at or after the end of the actuation operation of actuator 36. More specifically, the change in position represents a change in position of the shroud unit in a direction toward the material removal unit 12 (i.e., coincident with the feed direction X of the longwall mining system 10).

For determining the position change Δ p, the monitoring device 60 comprises a detection unit 64, i.e. in the form of a control unit, which is communicatively connected to the position change sensor 62. The detection unit 64 is configured to receive the measurement signal from the position change sensor 62 via a first signal line 65, on the basis of which the detection unit determines the position change Δ p. In an alternative configuration, the detection unit 64 and the position change sensor 62 may be wirelessly connected.

In the illustrated configuration, the position change sensor 62 is provided in the form of an acceleration sensor, also referred to as an accelerometer or motion sensor. The position change sensor 62 is included in the shroud unit 32 and is configured to measure the acceleration experienced by the shroud unit 32. In particular, the position change sensor 62 is configured to measure acceleration at least in the feed direction X, i.e. directed from the center of gravity of the shroud unit 32 towards the material removal unit 12. Therefore, the measurement signal generated by the position change sensor 62 is thus indicative of the magnitude of the acceleration of the shroud unit 32 in the feeding direction X.

Fig. 5 depicts a schematic diagram exemplarily illustrating the measurement signal generated by the position change sensor 62 during the actuation operation. In the diagram, the acceleration magnitude is shown as a function of time and is provided in the form of a curve g (t). The abscissa of the schematic depicts the magnitude of acceleration along the feed direction X, wherein a positive magnitude represents the acceleration of the shroud unit 62 towards the material removal unit 12. The ordinate of the figure depicts time, where t₀Indicates the start of an actuation operation and t_aIndicating the end of the actuation operation. Thus, from t₀Extend to t_aThe time period of (d) represents the duration of the actuation operation.

The resulting measurement signal is received by the detection unit 64 via a first signal line 65 and processed to determine the position change parameter Δ p. In particular, the amount of the solvent to be used,the detection unit 64 is configured to derive or calculate at least one area a under the curve g (t)_jAnd based on the derived area A_jThe position change Δ p is determined.

More specifically, the detection unit 64 is configured to first calculate the zero-crossing P of the signal or curve g (t) during the actuation operation_jI.e. at t₀And t_aWhere the measured acceleration is equal to zero. It is noted that at the beginning of the actuation operation (i.e., at time t)₀) And end (i.e., time t)_a) Is also considered as a zero crossing point P_j. The detection unit 64 then derives all areas a under the curve g (t)_jAbsolute value of (a). This is achieved by calculating two successive zero crossings P one after the other_jOf the measurement signal between. These absolute values are then summed to determine the position change Δ p. Therefore, the position change parameter Δ p determined by the detection unit 64 can be expressed as follows:

wherein j represents the total number of zero-crossings determined during the actuation operation, including the time t₀And t_aThe point of (d); and t_PiRepresenting zero crossing point P_iI.e. the abscissa value.

Alternatively or additionally, the detection unit 64 may be configured for comparing a portion of the measurement signal obtained during the actuation operation with another portion of the measurement signal obtained before or after the actuation operation. Based on this comparison, the detection unit 64 may detect whether the shroud unit 32 has been properly moved during the actuation operation, thereby determining whether a proper or fault condition of the mining machine unit 30 exists.

Alternatively or additionally, the detection unit 64 may be configured to further consider at least one further measurement signal obtained by a further position change sensor (i.e. an acceleration sensor) associated with at least one further mining machine unit arranged adjacent to the mining machine unit 30 incorporating the detection unit 64. Based on this, noise suppression can be performed on the measurement signal obtained by the position change sensor 62. In this way, a part of the measurement signal associated with the movement or acceleration of the shroud unit 32 caused by the actuating operation of the actuator 36 can be extracted.

As mentioned above, the illustrated monitoring device 60 utilizes an acceleration sensor. Such means measure the appropriate acceleration of the shroud unit 32. In other words, the acceleration sensor measures the acceleration of the shroud unit 32 relative to itself (e.g., relative to its initial position).

However, the monitoring device 60 is not limited thereto. Rather, any sensor unit may be used as the position change sensor 62 that is adapted to measure or determine a parameter indicative of a change in position of the shroud unit 32.

For example, in an alternative embodiment, the change of position sensor 62 may be configured to determine a change of position relative to at least one of the material removal unit 12, another mining machine unit connected adjacent to the mining machine unit 30, and the surroundings of the mining machine unit 30, the other mining machine unit being equipped with the monitoring device 60.

This may be achieved by a sensor unit which determines the distance between two points, i.e. a transmitter point and a receiver point, based on a running time or propagation time measurement of the signal transmitted between the two points. In other words, such a sensor unit determines the distance between two points. For example, such a sensor unit may be configured to determine or measure the time required for a signal to be transmitted from a transmitter to a receiver. This time is also referred to as the one-way delay. Alternatively, the sensor unit may be configured to determine the time required for a signal to be transmitted from the transmitter to the receiver and from the receiver back to the transmitter. This time is also referred to as the end-to-end delay. The shroud unit 32 may be equipped with a transmitter; and at least one of the material removal units 12, further mining machine units connected adjacent to the mining machine unit 30 are equipped with monitoring devices 60, and the surroundings of the mining machine unit 3Q may be equipped with receivers, or vice versa.

Such a sensor unit may use the electromagnetic signal to be detected. For example, the sensor unit may be an optical sensor unit that emits light such as a laser beam and detects reflected light. Alternatively, the sensor unit may use radio waves as signals to be transmitted and detected. Thus, the sensor unit may be a wireless sensor unit device, such as a Wi-Fi or bluetooth sensor device.

Furthermore, the sensor unit may be provided in the form of an odometer configured for determining a change in position of the shroud unit 32 relative to its surroundings (in particular the ground carrying the mining machine unit 30). For example, the shield unit 32 may be provided with at least one measuring wheel arranged at the bottom thereof, which is actuated when the shield unit 32 is moved. By measuring the movement of the measuring wheel, the odometer is able to determine the change in position of the shroud unit 32.

Step S1 further includes a second sub-step S1.2 of determining the stroke change of the actuator 36 during its actuation operation. In particular, the stroke change Δ s refers to a parameter indicative of the length of stroke change to which the piston 40 of the actuator 36 is or has been subjected during its actuation operation. In other words, the stroke change Δ s indicates the displacement of the piston 40 from its initial position, i.e., the displacement length. Thus, the stroke change Δ s indicates the displacement between the end position and the initial position of the piston 40 during the actuating operation. In this context, the term "initial position" refers to a position of the piston 40 at or before the beginning of the running operation, wherein the term "end position" refers to a position of the piston 40 at or after the end of the actuating operation.

To determine the stroke change as, the monitoring device 60 is provided with a displacement sensor 66 configured to determine the stroke change. The displacement sensor 66 may be, for example, a reed sensor or any other suitable sensor capable of determining the stroke or stroke change Δ s of the actuator 36 (i.e., its piston 40). As can be taken from fig. 3, a displacement sensor 66 is included in the actuator 36, i.e. the cylinder 38 thereof. The displacement sensor 66 is connected to the detection unit 64 by means of a second signal line 68, via which the displacement sensor transmits the determined stroke change Δ s to the detection unit 64. Alternatively, the displacement sensor 66 may wirelessly transmit the determined stroke change Δ s to the detection unit 64.

In a second step S2 of the method, the operation of the mining machine unit 3Q is monitored. This step is performed by means of the detection unit 64 and on the basis of the determined position change Δ p obtained in sub-step S1.1 and on the basis of the determined stroke change Δ S obtained in sub-step S1.2. More specifically, in a second step S2, the detection unit 64 of the monitoring device 60 determines whether the mining machine unit 30 (i.e. its connection to the material removal portion 12) is affected by a fault based on the determined position and stroke variations. In other words, the detection unit 64 detects whether the respective mining machine unit 30, i.e. its connection to the material removal unit 12, is in a failed state or in a suitable state.

In general, the detection unit 64 is configured to detect a fault or failure condition of the mining machine unit 30 when the change in position determined during the actuation operation does not indicate a suitable change in position of the shroud unit. Furthermore, the detection unit 64 is configured to detect a suitable status of the mining machine unit 3Q when the determined change of position indicates a suitable change of position of the shroud unit.

In order to determine whether the determined change in position Δ p indicates a suitable or sufficient change in position of the shield unit, the detection unit 64 is configured to compare the determined change in position with a threshold value. For example, the detection unit 64 may detect a fault condition when the determined position change Δ p does not exceed a threshold value, and detect a suitable state when the determined position change Δ p equals or exceeds the threshold value.

To this end, in order to determine whether the determined position change Δ p indicates a suitable or sufficient change of the position of the shield unit, the detection unit 64 is configured to determine whether the determined position change is correlated to a stroke change. In other words, in order to determine a suitable change in the position of the shield unit, the detection unit 64 further takes into account the determined stroke change. In particular, the detection unit 64 is configured to determine a suitable state of the mining machine unit 3Q when the determined position change Δ p is correlated with the determined stroke change Δ s, and to determine a failure condition when the determined position change Δ p is not correlated with the determined stroke change Δ s.

More specifically, in order to determine whether the determined position Δ p changes in the determined stroke change Δ are relevant, the detection unit 64 is configured to compare each of the determined values with a corresponding threshold value, as depicted in fig. 4 by sub-steps s.2.1 and S2.3.

In a first sub-step 2.1, the detection unit 64 is configured to compare the determined absolute value of the stroke change Δ s with a first threshold value T1. If the absolute value of the determined stroke change as is equal to or greater than the first threshold value T1, the detection unit 64 proceeds to a second substep S2.2 as shown in fig. 4. However, if the determined absolute value of the stroke change is below the first threshold T1, the detection unit 64 proceeds to a third step S3 of the method, wherein the detection unit 64 outputs a fail status signal, which is transmitted via the third signal line 69 or wirelessly to the central control unit 58. The fault status signal indicates to the central control unit 58 that the mining machine unit 30 in question is affected by the fault.

In a second sub-step S2.2, the detection unit 64 calculates a second threshold value T2 based on the determined stroke change Δ S. Thereafter, in a third sub-step S2.3, the detection unit 64 compares the determined position change Δ p with a second threshold value T2. If the detection unit 64 determines that the absolute value of the determined position change Δ p is lower than the second threshold value T2, the detection unit 64 proceeds to a third step S3 and outputs a fail-state signal to the central control unit 58. However, if the detection unit 64 in sub-step S2.3 determines that the absolute value of the determined position change Δ p is equal to or greater than the second threshold value T2, the detection unit 64 proceeds to a fourth step S4, in which fourth step S4 the detection unit 64 outputs a suitable condition signal, i.e. is transmitted to the central control unit 58 via the third signal line 69 or wirelessly. The appropriate status signal indicates to the central control unit 58 that the mining machine unit 30 in question is in an appropriate status.

Referring to fig. 6, another configuration of the monitoring device 60 is specified. According to this arrangement, the monitoring device 60 is provided in the form of a passive monitoring device, as shown in fig. 6, fitted to the plurality of discs 44 of the armored face conveyor 14. Specifically, the monitoring device 60 utilizes Time Domain Reflectometry (TDR). In general, TDR involves sending pulses of energy through a transport medium and measuring the reflections and properties of the medium changes. In this way, changes or faults in the transmission line, i.e. the transport medium, can be detected and located. Alternatively, the monitoring device 60 may use variations in TDR, such as frequency domain reflectometry or spread spectrum techniques.

Specifically, the monitoring device 60 includes a transport medium 70 secured to the armored face conveyor 14 to extend along the plurality of coils 44, i.e., along the coil line. In the configuration shown in fig. 6, the transport medium 70 is a fiber optic cable attached on its bottom side to the plurality of trays 44. To protect the transport medium 70, a hose 72 is provided for receiving and containing the transport medium 70. Within the hose 72, the transport medium 70 is loosely spiraled.

At each tray 44, the hose 72 is provided with a recess or hose cut 74 for exposing the transport medium 70. A machine link 76 is mounted to the exposed portion of the transport medium 70, the machine link configured to manipulate the signal transmission characteristics of the transport medium 70 based on the machine force acting on the wire holder 78.

In the illustrated arrangement, the machine link 76 includes two lever arms 80 rotatably fixed to each other at a first end. The cord retainer 78 is attached to a first end of a lever arm 80. The machine link 76 is provided such that when the cord holder 78 is pulled in a direction Y pointing away from the lever arm 80, the second ends of the lever arm 80 disposed opposite the first ends approach each other. Further, a spring element 82 is arranged between the second ends of the lever arms 80, which biases the second ends together.

The transport medium 70 is attached to the machine link 76 such that the transport medium 70 is continuously secured to the second end of a first of the two lever arms 80, the first end of the same lever arm 80, and the second end of the other of the two lever arms 80, as shown in fig. 6. With such a configuration, the bend radius of the transport medium 70, and thus the signal transmission characteristics of the transport medium, may be changed upon actuation of the machine link 76, i.e., the cord holder 78. Therefore, when no tensile force is applied to the pull-cord holder 78, the conveyance medium 70 is subjected to the largest bending radius, which impairs the signal transmission characteristics of the conveyance medium 70.

The pull-cord retainer 78 of the machine link 76 is connected to the cylinder 38 of the actuator 36 by a cord 84 (i.e., made of steel). The cord 84 extends on the underside of the actuator 36 so as to be protected from falling material. The connection between the cord 84 and the cord retainer 78 is provided such that when the connection between the actuator 36 (i.e., the piston 40 thereof) and the armored face conveyor 14 (i.e., the disc 44 thereof) is released, the connection between the cord 84 and the cord retainer 78 is also released. Therefore, when the connection between the actuator 36 and the armored face conveyor 14 is released, the maximum bending radius of the transport medium 70 is set, thereby impairing the signal transmission characteristics thereof.

The monitoring device 60 further comprises a sensor unit (not shown) for determining the signal transmission characteristics of the transport medium and thus for determining the change in position of the shield unit 32 during the actuation operation of the actuator 36. Specifically, the sensor unit is provided in the form of a TDR sensor head attached to one end of the transport medium 70 at the disc line side end. The sensor unit comprises a pulse generator for generating energy pulses, which are transmitted through the transport medium 70. Furthermore, the sensor unit comprises a sensor for measuring the reflection of the energy pulse, on the basis of which the signal transmission characteristics of the transport medium 70 are determined. These measured reflections represent changes in the position of shroud unit 32.

The measured reflections are transmitted to a detection unit (not shown) of the monitoring device 60, which is configured to determine, based on the measured reflections, whether the transport medium 70 comprises bad signal transmission characteristics and at which position on which length the transport medium 70 is present. In this way, the detection unit is configured to determine at which pan 44 of the armored face conveyor 14 the machine link 76 is released, thereby indicating which mining machine unit 30 is released from the armored face conveyor 14 and is therefore affected by the fault. The sensor unit is configured to continuously analyze the line characteristics of the transport medium 70 from the sensor head to the line terminal.

The monitoring device 60 utilizing TDR is considered a passive monitoring device because no energy storage device or active components are required in the disc line. All of the electronics may be disposed in an electrical chamber disposed at a side end of the wiring harness.

In an alternative embodiment, the transport medium 70 may be provided in the form of a cable, i.e., a copper cable. Thus, the machine link 76 may be provided in the form of an electrical switch that interrupts the electrical connection of the conveyance medium 70 in the released state.

It will be apparent to those skilled in the art that these embodiments and items depict only examples of the various possibilities. Thus, the embodiments illustrated herein should not be construed as limiting such features and configurations. Any possible combination and configuration of the features described may be selected in accordance with the scope of the invention.

A method for monitoring the operation of a mining machine unit, in particular a longwall mining system, may be provided. The mining machine unit to be monitored may comprise a shield unit, which is connected to the material removal unit by means of an actuator for adjusting the distance between the shield unit and the material removal unit. The method may comprise the steps of: determining a change in position of the shroud unit during an actuation operation of the actuator; and detecting a fault of the mining machine unit based on the determined change in position.

Typically, in such mining machine units, the actuator is connected to at least one of the shroud unit or the material removal unit by means of a shear pin. The shear pins may be configured for releasing the connection between the mining machine unit and the armored face conveyor when a machine force acting on the individual shear pins exceeds a predetermined value. In this way, the shear pin may form a predetermined breaking point for protecting the mining machine unit from excessive loads that may cause irreparable damage.

The fault condition of the mining machine unit may be due to a shear pin breaking. In the proposed method, a fault or failure state of the mining machine unit is detected based on a change in position determined during an actuation operation of the actuator. In this way, the proposed method can avoid monitoring the state of the shear pin directly during operation. Such measures, i.e. measures for directly monitoring the status of the shear pin, would require the arrangement of a sensor unit on the outer surface of the mining machine unit (i.e. the actuator). However, due to the strong environmental conditions of the machine during operation of the mining machine unit, such a sensor unit would be subjected to excessive machine forces and would therefore require a robust and expensive design.

Thus, by detecting a malfunction of the mining machine unit based on a change of position of the shroud unit, a robust method may be provided which may otherwise be cost-effectively implemented.

The proposed method may be used in or for a longwall mining system comprising a plurality of mining machine units. However, the method is not limited to this application and may be used in connection with any mining or material removal system comprising at least one mining machine unit as described above.

In the mining machine unit, the actuator may be configured for adjusting a distance between the shroud unit and the material removal unit. As described above, the position change of the shroud unit is determined during the actuation operation of the actuator. The actuating operation may refer to an operation of the actuator for reducing a distance between the shield unit and the material removing unit. Alternatively, the actuating operation may refer to an operation of the actuator for increasing the distance between the shield unit and the material removal unit. The actuator may be a linear actuator. Thus, the actuation operation may be a retraction operation of the actuator or an extension operation of the actuator. The actuator may comprise a cylinder and a piston received in the cylinder, wherein upon actuation of the actuator the piston moves, i.e. retracts or extends, relative to the cylinder.

As described above, the step of determining a change in position is performed during an actuation operation. In particular, the change in position may be a parameter indicative or indicative of the distance, i.e. the displacement length, of the shield unit, in particular relative to the initial position of the shield unit. In other words, the change in position may indicate or represent a displacement of the shield unit relative to the position of the shield unit at the start of the actuation operation. More specifically, the change in position may indicate or represent a change in position of the shroud unit at least in a direction towards the material removal unit. The direction may coincide with a feeding direction of the mining machine unit or the longwall mining system.

To determine the change in position, a change in position sensor may be used. For example, the position change sensor may be configured to determine a change in position of the shield unit relative to itself, i.e. relative to an initial position. For this purpose, the position change sensor may be an acceleration sensor, also referred to as a motion sensor or accelerometer. In other words, the change in position can be determined by means of an acceleration sensor.

The acceleration sensor may be included in the shield unit. By using such a position change sensor, it may be avoided that a measuring unit required for monitoring the operation of the mining machine unit, i.e. for detecting a malfunction or a suitable state thereof, is attached to an outer surface of the mining machine unit. The proposed solution therefore allows to prevent the components required to perform the proposed method from being exposed to excessive machine loads. In this way, the robustness of the apparatus for performing the method and thus of the method itself can be ensured.

However, the position change sensor is not limited thereto. Rather, any sensor unit suitable for measuring or determining a parameter indicative of a change in position of the shield unit may be used as the change in position sensor.

For example, in an alternative embodiment, the position change sensor may be configured to determine a change in position relative to at least one of the material removal unit, another mining machine unit arranged adjacent to the mining machine unit, and the surroundings of the mining machine unit (in particular the ground carrying the mining machine unit).

This may be achieved by a sensor unit which determines the distance between two points, i.e. a transmitter point and a receiver point, based on a running time or propagation time measurement of the signal transmitted between the two points. The sensor unit may comprise a transmitter arranged in or on at least one of the shield unit and the actuator and a receiver or transmitter arranged in or on the material removal unit, or vice versa.

Such a sensor unit may use an electromagnetic signal as the signal to be transmitted and detected. For example, the sensor unit may be an optical sensor unit that emits light such as a laser beam and detects reflected light. Alternatively, the sensor unit may use radio waves as signals to be transmitted and detected. Thus, the sensor unit may be a wireless sensor unit device, such as a Wi-Fi or bluetooth sensor device.

In a further step of the method, a fault or failure state of the mining machine unit is detected on the basis of the determined change in position, as described above. This step may be performed such that a fault condition of the mining machine unit is detected when the determined change in position does not indicate a suitable change in position of the shroud unit during the actuation operation, and a suitable condition of the mining machine unit is detected when the determined change in position indicates a suitable change in position of the shroud unit.

To determine whether the determined change in position is indicative of a suitable or sufficient change in position of the shroud unit, the determined change in position may be compared to a threshold value. For example, in the step of detecting a fault, a failure state of the mining machine unit may be detected when the determined change in position does not exceed a threshold value, and wherein a suitable state of the mining machine unit may be detected when the determined change in position equals or exceeds the threshold value.

In the method, the threshold value may be determined according to an actuation operation of the actuator. For example, the threshold may be determined based on the duration of the actuation operation. Alternatively, the threshold value may be determined based on a stroke change of the actuator (i.e., during an actuation operation).

The method may further comprise the step of determining a change in stroke of the actuator during an actuation operation thereof. Furthermore, the step of detecting a malfunction of the mining machine unit may be performed based on the determined stroke variation. In other words, in the step of detecting a malfunction of the mining machine unit, a malfunction of the mining machine unit is detected based on the determined position change and the determined stroke change.

In particular, the stroke change may refer to a parameter indicative or indicative of the length of the stroke change, in particular with respect to the initial stroke of the actuator before being operated in an actuation operation of the actuator. In other words, the stroke change may be indicative or representative of the displacement of the piston relative to the cylinder during the actuation operation, i.e. the displacement length.

In a further development, in the step of detecting a fault, a fault state of the mining machine unit can be detected when the determined stroke variation is not correlated with the determined position variation, and wherein a suitable state of the mining machine unit can be detected when the determined stroke variation is correlated with the determined position variation.

For example, to determine whether the determined position change and the determined stroke change are related, each of the determined position change and stroke change may be compared to a threshold value, respectively. Therefore, in the step of detecting a malfunction, the malfunction state may be detected when the absolute value of the determined stroke variation is greater than a first threshold value or when the absolute value of the determined position variation is less than a second threshold value. Further, a suitable condition may be detected when the absolute value of the determined stroke change is equal to or greater than a first threshold and the absolute value of the determined position change is equal to or greater than a second threshold.

In a further development, the second threshold value may be determined on the basis of the determined stroke variation. In this way, the second threshold may be dynamically adjusted.

In the following, the structural configuration of the actuators of the mining machine unit is specified. In particular, the actuator may be connected to at least one of the shroud unit and the material removal unit by a shear pin. The shear pin may be configured to release the connection between the actuator and at least one of the shroud unit and the material removal unit when a machine force acting on the shear pin exceeds a predetermined value. Furthermore, the actuator may be a linear actuator, in particular a telescopic actuator comprising a cylinder fixed to the shroud unit and a piston fixed to the material removal unit, or vice versa. In other words, the cylinder may be arranged on the shroud unit side of the actuator and the piston may be arranged on the material removal unit side. Alternatively, the piston may be arranged on the shroud unit side of the actuator and the cylinder may be arranged on the material removal unit side.

Furthermore, a monitoring device for monitoring the operation of the mining machine unit may be provided. The mining machine unit may comprise a shroud unit connected to the material removal unit by an actuator, the actuator being configured for adjusting a distance between the shroud unit and the material removal unit. In particular, the monitoring device may comprise a sensor unit for determining a change in position of the shroud unit during an actuation operation of the actuator and a detection unit for detecting a malfunction of the mining machine unit based on the determined change in position.

The monitoring device may specifically be arranged for performing or carrying out the above-mentioned method. Thus, the technical features described in connection with the above-described method may also relate to and apply to the proposed monitoring device and vice versa.

As described above, the monitoring device may comprise a sensor unit and a detection unit. These units may refer to functional units that may be assigned to different components or to a single component. In particular, the detection unit may be configured to perform the method as described above. Furthermore, the sensor unit may be or comprise an acceleration sensor.

To this end, a mining machine unit for use in a longwall mining system may be provided. The mining machine unit comprises a monitoring device as described above. Thus, the technical features described in connection with the monitoring device and the monitoring method may also relate to and apply to the proposed mining machine unit and vice versa.