BACKGROUND

The invention relates to mining machines, and more particularly to a method and arrangement for monitoring phenomena in connection with a mining machine.

Different types of phenomena are measured in connection with mining machines. These measurements can be used for instance for controlling the operation of the mining machine and/or for receiving information about the mining machine, the material to be mined and the mining environment.

The conventional sensors are typically electrical sensors that convert physical effect on the sensor element into an electrical signal. Electrical sensors require electrical connections, wires and electronics which require mechanical engineering and space and are vulnerable to environmental disturbances. Each measurement signal or measured phenomena usually also needs a separate sen- sor or multiple sensors, which make the system and the installations complicated.

Typical electronic sensor systems used commonly in mining equipment consist of a power source, a sensor element, a measurement transceiver, I/O cabling, analogue to digital converter and bus or network cabling. A considerable amount of vulnerable and space consuming electronics and cabling is, thus, need- ed to measure a physical value from the sensor element to be usable by the computing hardware and algorithms. On a system level, for instance hundreds of electrical connections may be required.

BRIEF DESCRIPTION

An object of the present solution is to provide a new method and arrangement for monitoring phenomena in connection with a mining machine. The objects of the solution are achieved by a method and an arrangement, which are characterized by what is stated in the independent claims. Some embodiments of the invention are disclosed in the dependent claims.

The solution is based on the idea of providing a mining machine with at least one optical fibre and at least one monitoring unit, and using the optical fibre itself as a sensing element. Thus, a need for electrical connections arranged on the mining machine is eliminated or at least decreased considerably. In addition, the optical fibre based sensing is naturally flameproof, which is beneficial in many applications and required for instance in coal mining. As added electrical connections and separate conventional sensor elements are no longer needed, a larger number of measurements can be made in a manner that is simpler and more robust in harsh environments.

Some other advantages of the solution are discussed in connection with the detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following the invention will be described in greater detail by means of preferred embodiments with reference to the attached [accompanying] drawings, in which

Figure 1 illustrates an example of a mining machine and an arrangement in the mining machine;

Figure 2 illustrates schematically an arrangement in connection with a mining machine;

Figure 3 illustrates schematically a method for monitoring phenomena in connection with a mining machine;

Figures 4a, 4b, 4c and 4d illustrate schematically cross sections of optical fibres according to different embodiments; and

Figure 5 illustrates schematically an embodiment of a control systems for an arrangement for monitoring phenomena in connection with a mining ma- chine.

DETAILED DESCRIPTION OF THE INVENTION

Different types of mining machines are known in the art and it is clear for a person skilled in the art that the figures are provided for illustrative purposes only and the solutions described in this description are applicable also for min- ing machines with different configurations and structure. The mining machine 1 may, thus, comprise for instance at least one of the following: a rock drilling rig, a crusher, a continuous mining machine, a loader, and a dump truck.

Figure 1 illustrates an example of a mining machine 1 and an arrangement for monitoring phenomena in connection with a mining machine 1 and Figure 2 illustrates an arrangement for monitoring phenomena in connection with a mining machine 1 schematically. In the embodiment of Figure 1, the mining machine 1 comprises a mobile rock drilling rig comprising a movable carrier 2 provided with several wheels 3, a driver cabin 4 and booms 5. These are also some examples of structural parts of a mining machine 1, but a mining machine may also comprise numerous other types of structural parts, such as actuators, joints, tools and so on. The mining machine 1 is further provided with a control system which includes at least a first control unit (not shown) configured to control actuators in the mining machine 1 for controlling and operating the machine. However, the mining machine may, thus, comprise a different type of a mining machine instead of a rock drilling rig.

The arrangement for monitoring phenomena in connection with a mining machine 1 may comprise at least one optical fibre 6 provided in connection with the mining machine 1 and used as a sensing element for sensing at least one phenomenon related to the mining machine using a beam of light transmitted to the optical fibre 6. This kind of an approach where an optical fibre 6 is used as a sensing element, in other words as a sensor, is referred to as distributed sensing, such as in distributed strain sensing, distributed temperature sensing and distributed acoustic sensing, in this description. Similar approach also enables three- dimensional shape sensing. In other words, in distributed sensing an optical fibre as a whole acts as a sensor/sensing element.

The arrangement for monitoring phenomena in connection with a mining machine 1 may also comprise at least one monitoring unit 7 for monitoring light returning from the at least one optical fibre and for converting the data received in the form of the light returning from the at least one optical fibre into at least one measured quantity value describing the at least one phenomenon, wherein the measured quantity is suitable for use in the control and/or monitoring of the mining machine. In other words, the light backscattered from the optical fibre 6 may be analysed and the phenomenon may be monitored based on the analysis results converted into the measured quantity value (s). Each optical fibre 6 may be connected to the monitoring unit 7 at least at one end of the optical fibre. In different embodiments, the monitoring unit may be arranged fixedly or removably in connection with the mining machine 1. According to an embodiment, the monitoring unit 7 may comprise a fibre interrogator. According to a further embodiment, another controller, such as a control unit of the mining ma- chine, may be used to further process the data provided by the optical fibre 6 and the monitoring unit 7 for use for monitoring and controlling of a mining machine or for some other purpose. An embodiment of a control system is illustrated schematically in connection with Figure 5.

Figure 3 illustrates schematically a method for monitoring phenomena in connection with a mining machine. Such a method may be executed by a mining machine 1 and/or an arrangement such as described in this description. The method may comprise sensing 31 at least one phenomenon related to the mining machine 1 by at least one optical fibre 6 provided in connection with the mining machine 1 and used as a sensing element and a beam of light transmitted to the optical fibre. The method may also comprise monitoring 32 light returning from the at least one optical fibre 6 by a monitoring unit 7. The method may further comprise converting 33 the data received in the form of the light returning from the at least one optical fibre 6 into at least one measured quantity value describing the at least one phenomenon.

Additionally, the method may comprise utilizing 34 the measured quantity in the control and/or monitoring of the mining machine 1. The measured quantity may be utilized in the control and/or monitoring of the mining machine 1 in a manner similar to corresponding measured quantities provided by conventional methods, but the method and the arrangement described in this description provide many benefits over the conventional data gathering methods, such as those related to flame proof monitoring, simple monitoring configuration that is easy assemble even to an existing machine and the numerous measured quantities that may be provided by a single optical fibre 6 provided in connection with the mining machine 1. For example, the condition of the mining machine 1 may be monitored by utilizing measured quantities of strain for monitoring the structure load and pressure, such as hydraulic pressure; measured quantities of temperature for monitoring the temperature of components and/or the temperature of pressure medium, such as hydraulic oil, or other fluids in reservoirs, hoses, pipes or conduits of the mining machine; and/or measured quantities of vibrations/acoustics to monitor acoustic signals or other vibrations in structures, components and/or in air or fluids; wherein the measured quantities are based on the information received from the optical fibre(s) used as a sensing element. Similarly, position of the structural parts of the mining machine 1 may be controlled by utilizing measured quantities of shape for determining relative position or orientation of the structural parts of the mining machine 1 in relation to one another; and a work result may be monitored by utilizing measured quantities of shape for monitoring quality and accuracy of a drilling point and a drilling angle of a drill hole compared to a drilling plan, for example.

In other words, in the method for monitoring phenomena in connection with a mining machine, a measured quantity may be provided by at least one optical fibre 6 provided in connection with the mining machine 1 and a monitoring unit 7. Using an arrangement and/or a method described in this description and/or in the claims, the considerable amount of vulnerable and space consuming components, electrical connections and cabling needed in conventional arrangements and methods for measuring a physical value using conventional sensor el- ements and converting the data into a form usable for the computing hardware and algorithms can be replaced by a single optic fibre.

According to an embodiment, the at least one measured quantity value may be updated continuously at a rate of at least 0.2 Hz. According to another embodiment, the at least one measured quantity value may be updated at a rate of 2 to 10 Hz. Typically, a more frequent update is more useful and gives more realtime data needed especially in the control of the mining machine 1, but a suitable update rate may depend on the application. For instance for maintenance related monitoring purposes a lower update rate might be sufficient. Continuous updating of the measured quantity value may take place during use of the mining ma- chine 1, the operation, work phase and/or structural part of the mining machine 1.

According to an embodiment, multiple sensors may be multiplexed along the length of the at least one optical fibre 6. That way the amount of data collected by a single optical fibre 6 may be increased significantly. According to an embodiment, one optical fibre 6 may be used to measure at least two separate components and/or structural parts of the mining machine 1.

According to an embodiment, two or more optical fibres may be provided in connection with the mining machine 1. This may further increase the amount and the type of data that can be collected using such an arrangement and such a method in connection with such a mining machine 1. It also enables measurement of a multitude of phenomena using a single measurement technology.

Figures 4a, 4b, 4c and 4d illustrate schematically cross sections of optical fibres according to different embodiments. These embodiments comprise at least one optical fibre core 6a and a protective layer 6b surrounding the optical fibre core 6a. The optical fibre cores and the protective layer are not shown to scale but to illustrate the principle only. Figure 4a illustrates an embodiment, wherein a single cable comprises an optical fibre core 6a and a protective layer 6b surrounding the optical fibre core 6a.

According to an embodiment, at least three optical fibre cores 6a may be provided together as a single cable with a common protective layer 6b. Such embodiments are illustrated in Figures 4c and 4d. According to a further embod- iment, at least three optical fibre cores may be provided together as a single cable with a common protective layer and with a 120 degree alignment between the optical fibres within the cable. An example of such an embodiment is shown in Figure 4c. According to another embodiment, at least three optical fibre cores may be provided as separate cables with separate protective layers and arranged fixedly to one another. According to a further embodiment, three optical fibre cores may be provided as separate cables with separate protective layers and arranged fixedly to one another with a 120 degree alignment between the optical fibres. An example of such an embodiment is shown in Figure 4b. These embodi- ments may enable more advanced measuring possibilities, such as 3D shape sensing. According to an embodiment, four or more optical fibres may be provided as a bundle comprising a common protective layer and/or separate protective layers. This may enable even more advanced, complex and accurate measurements to be made. In such embodiments, each optical fibre core 6a or each cable com- prising optical fibre core(s) and protective layer(s) may be considered as an optical fibre 6 in the sense of the other embodiments described in this description. According to an embodiment, the protective layer comprises a shock absorbing rubber material.

According to an embodiment, the at least one optical fibre is used for at least one of the following sensing methods: distributed strain sensing, distributed temperature sensing, distributed acoustic sensing and three-dimensional shape sensing. According to an embodiment, at least two or three of these sensing methods are provided by the one and the same optical fibre. This enables measurement of a multitude of phenomena using a single measurement technology and/or controlled by a single monitoring unit. All these methods are useful in mining environments and used separately or in combination they may be used for more versatile measuring with a much simpler sensor arrangement than what has been possible using conventional sensors. According to an embodiment, an optical fibre 6 may comprise for instance at least one strain sensing segment, at least one acoustic sensing segment, at least one shape sensing segment and/or at least one temperature sensing segment distributed along the length of the optical fibre 6. The methods for providing such sensing segments, such as fibre Bragg gratings (FBG) for temperature and strain sensing, on an optical fibre are known as such and therefore they are not described here in more detail.

According to an embodiment, the phenomenon related to the mining machine describes a condition, a position and/or a work result. The phenomenon may, thus, describe for instance a condition of the process and/or the mining machine 1 itself, such as an accumulated load or a load peak of a structural part/component, like the crane or boom, a joint or an actuator; a position comprising the location and orientation of at least two structural parts of the mining machine 1 in relation to one another; and/or a work result such as quality and accuracy of a work product, such as a drilling point and a drilling angle of a drill hole compared to a drilling plan; and so on. According to an embodiment, the phenomenon related to the mining machine may comprise at least one of the following physical phenomena: temperature of a component of the mining machine; surface temperature of a component of the mining machine; temperature of a fluid in reservoirs, pipes and/or conduits inside components of the mining machine, such as hydraulic oils, motor oils, transmission oils, cooling liquids, flushing fluids and other types of fluids present in the mining machine; ambient air temperature or air temperature before and after coolers of the mining machine; strain or load in or at the surface of load bearing structures of the mining machine; hydraulic pressure in pipes, hoses, chambers or conduits inside components of the mining machine; acoustic signals or vibrations in components, structures; and fluid volumes in the mining equipment of the mining machine. This is particularly beneficial, as many of the measurements are challenging to arrange accurately and ro- bustly enough using conventional sensors, especially in mining environments where the conventional sensors are exposed to dust, moisture, hits and other types of mechanical damages and where electrical wiring may cause safety issues.

The at least one optical fibre 6 may, thus, be provided in connection with the mining machine 1. More particularly, according to an embodiment, the at least one optical fibre 6 may be provided at least partly within at least one structural part of the mining machine. A benefit of such an embodiment is that the structural part protects the optical fibre 6 from external mechanical damages, such as hits by falling rocks and so on. According to another embodiment, the at least one optical fibre 6 may be provided at least partly on a surface of at least one structural part of the mining machine 1. In other words, the at least one optical fibre 6 may be provided at least partly on a surface of at least one structural part of the mining machine 1 in addition to or instead of being provided at least partly within at least one structural part of the mining machine 1. These structural parts may comprise a same structural part of the mining machine 1 and/or separate structural part(s) of the mining machine 1.

Figure 5 illustrates schematically an embodiment of a control system for an arrangement for monitoring phenomena in connection with a mining machine 1. This is only an example of a control system that may be used for monitoring phenomena in connection with the mining machine and for executing the methods described in this description and utilizing the arrangements described in this description for controlling and/or monitoring of the mining machine. The control system may comprise graphical user interfaces (GUI1, GUI2) provided in connection with the mining machine 1 for user interaction and for visualizing the measured quantities, for example, for the end user; interfaces to external networks, data transfer in and out and for remote user interfaces (Remote); control- lers such as a master controller for mining machine level control and diagnostics, and other controllers for power, boom(s), carrier, valve(s) and controllers for other components and operations related to the mining machine; monitoring unit(s) (Optic interrogator) and/or optical fibres 6. The control system may also comprise valves (V) for instance for controlling tools, actuators and operations of the mining machine 1. According to an embodiment, the control system may comprise conventional sensors as well.

According to an embodiment, the at least one optical fibre may be retrofitted to an existing mining machine. This is beneficial, as a more simple, reliable and robust monitoring method with more advanced measurement possibili- ties may be applied to an existing mining machine.

According to an aspect, a mining machine 1 may comprise an arrangement described above. The mining machine 1 may, thus, comprise for instance at least one of the following: a rock drilling rig, a crusher, a continuous mining machine, a loader, and a dump truck.

It will be obvious to a person skilled in the art that, as the technology advances, the inventive concept can be implemented in various ways. The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.