Apparatus and method for controlling flashing in rock drilling

Abstract

Apparatus, method and computer program product for controlling flushing in rock drilling and rock drilling rigs. The apparatus includes a control unit (CU) and a computer program (22) for controlling the supply of a liquid component (LC) in an air mist flushing system in response to a detected seepage rate (15) of the drilling performed. An operator (22) can set a desired moisture target value (16) for the cuttings (19) removed from the drill hole (12) and the control system automatically adjusts the flushing system to control the supply of the liquid component.

Description

[Technical field]

[0001] The present invention relates to a device for controlling air mist flushing of a drilling unit in rock drilling. The air mist comprises pressurized air and one or more liquid components. The air mist is used to flush the drilled hole.

[0002] The invention further relates to a rock drilling rig, and to a method and computer program product for controlling an air mist flushing system.

[0003] The field of the invention is more particularly defined in the preambles of the independent claims.

[0004] In mines and other work sites, different types of rock drilling rigs are used to drill drill holes into the rock surface. The rock drilling rig is provided with one or more booms, the rock drill being arranged at the distal end of the boom. During drilling, dust and larger sized drilling cuttings are formed which need to be removed from the drill hole. The rock drill is therefore provided with a flushing device for supplying a flushing fluid through the drilling tool to the inside of the drill hole. The flushing medium may be air, water or mist. There are different solutions for controlling the flushing process and the supply of the flushing fluid. However, the known solutions show some drawbacks. Summary of the Invention

[0005] It is an object of the present invention to provide a new and improved apparatus, method and computer program product for controlling air mist flushing, and further to provide a new and improved rock drilling rig utilizing the disclosed solution.

[0006] The device according to the invention is characterized by the characterizing features of the first independent device claim.

[0007] The rock drilling rig according to the invention is characterised by the characterising features of the second independent equipment claim.

[0008] The method according to the invention is characterized by the characterizing features of the independent method claim.

[0009] A computer program product according to the invention is characterised by the characterising features of the third independent device claim.

[0010] The concept of the disclosed solution is that the device comprises one or more control units for controlling the supply of pressurized air and an air mist comprising one or more liquid components. The control unit is provided with data relating to the infiltration rate of the excavation. The control unit thereby generates control signals for controlling the supply of the one or more liquid components of the air mist in response to the input data relating to the infiltration rate. The control unit may also be provided with input parameters influencing the flushing control performed.

[0011] In other words, the water content of the supplied air mist is adjusted in relation to data on the penetration rate, which means the advance of the drill bit into the rock over a period of time. Typically, the penetration rate is expressed in m / min.

[0012] The objective of the disclosed solution is to influence the properties of the cuttings removed by flushing from the drill hole, mainly by adjusting the liquid content in the air mist. Furthermore, the objective is to keep the moisture level of the removed cuttings relatively constant, despite possible variations in the infiltration rate during the drilling of one drill hole. The system can then react to, for example, fluctuating rock properties and other external variations.

[0013] The advantage of the disclosed solution is that, if the amount of liquid content in the air mist and other flushing parameters are properly adjusted, clogging and other problems with drilling cuttings can be avoided. If the moisture concentration is too high, clogging can occur. On the other hand, if the moisture level is too low, dust can cause serious problems. In this solution, moisture-based flushing can not only prevent clogging and dusting problems, but also save energy and flushing medium, and furthermore, it can ensure full drilling efficiency and keep the work site and rock drilling rig cleaner.

[0014] Moreover, the disclosed operator-free flushing control is well suited for unmanned drilling processes and remote controlled drilling.

[0015] According to one embodiment, the penetration rate can be determined in a generic manner by different detection means: It is possible to detect the movement of the rock drill on the feed beam of the rock drilling unit by one or more sensors or detection devices. Alternatively, it is possible to detect the operation of the feed device and determine, for example, the flow rate of the working fluid fed to the feed cylinder of the drilling unit and determine the penetration rate based on the detected flow.

[0016] According to one embodiment, the supply of liquid components is automatically adjusted when the infiltration rate changes due to external factors such as changes in rock quality, which can indirectly indicate lithology, thereby indirectly controlling the water content depending on the rock properties.

[0017] According to one embodiment, the disclosed solution can also detect the drilling parameters selected by the operator and control the supply of the liquid components based thereon. The operator can, for example, decrease the drilling penetration rate by decreasing the impact pressure of the impact device, thereby trying to improve the straightness of the drill hole when drilling demanding rocks. The system can monitor the input drilling parameters and can perform the necessary controls for flushing.

[0018] According to one embodiment, the liquid component may be water, an aqueous solution or any suitable liquid mixture.

[0019] According to one embodiment, the control unit is configured to inspect each drill hole separately and to possibly perform the disclosed corrective measures for each drill hole, in other words, the control unit is configured to inspect each drill hole incrementally as drilling progresses and to perform the disclosed corrective measures accordingly.

[0020] According to one embodiment, the control unit may be provided with an input target value for the moisture content of the cuttings removed from the drill hole being drilled. The control unit may also determine an actual value for the moisture content of the cuttings, and then compare the input target value with the actual value and adjust the supply of the liquid component based on the comparison.

[0021] According to one embodiment, the control unit is configured to communicate with at least one user interface by means of which an operator can input desired target values ​​into the control unit.

[0022] According to one embodiment, the above-mentioned user interface may include visual or graphic display elements for inputting the target value. The visual or graphic display elements may be intuitive and may improve user convenience.

[0023] According to one embodiment, the input target and actual values ​​are relative values.

[0024] According to one embodiment, the input target and actual values ​​are percentage values, so the value under investigation is the percentage of moisture.

[0025] According to one embodiment, the control unit is configured to calculate the removal rate of the removed cuttings per period during drilling in response to input data on the diameter of the drill bit, data on the density of the drilled rock material and the penetration rate, and to calculate the required liquid component supply rate in response to the input target value of the moisture content and the calculated data on the removal rate of the cuttings. In other words, the control unit is configured to determine the actual value of the moisture content by a calculation process. And there is no need to provide the control unit with detection data of the actual moisture content. Thus, in this embodiment, an indirect control principle is implemented.

[0026] According to one embodiment, the calculated removal rate of flushed cuttings per time period during drilling indicates the volumetric amount of solid rock removed per time period, and can therefore be referred to as the volumetric infiltration rate. The supply of pressurized air and liquid components needs to be adjusted according to the detected volumetric infiltration rate so that the desired moisture content value can be reached.

[0027] According to one embodiment, the control unit is provided with input data relating to the density of the rock material to be excavated, or alternatively the control unit is provided with sensing data during the excavation process, and is configured to determine the density of the rock material in response to the sensing data. The control unit may be provided with suitable algorithms for performing the density calculation or determination.

[0028] According to one embodiment, the control unit is provided with detection data relating to the actual moisture of the drill cuttings removed from the drill hole, whereby a feedback control is provided, and the control unit is configured to control the supply of the liquid component in response to the input feedback data. In this embodiment, there are one or more sensors or detection devices configured to detect the moisture of the cuttings. The sensor may for example be arranged in association with the dust collection system.

[0029] According to one embodiment, the disclosed solution includes flushing parameters input to a control unit, the input control parameters including a data set regarding allowable moisture values ​​for the moisture content of the cuttings. The allowable moisture values ​​can be determined by actual testing and measurements. Furthermore, the data set may be customized for, for example, different drilling situations, rock types, drilling tools.

[0030] According to one embodiment, the control unit is configured to prevent control situations where the delivery of the liquid component results in a flashing situation of the air mist outside of a permitted moisture value defined by the input data set.

[0031] According to one embodiment, the acceptable flushing parameters or data sets are indicated by a predefined flushing map. For example, there may be different flushing parameters and flushing maps based on actual studies performed for different rock properties and drilling tools.

[0032] According to one embodiment, the control unit can automatically select such control parameters from a data set on permissible moisture values ​​that minimize the supply of liquid components. In other words, this embodiment utilizes the lowest possible moisture content, but still takes care not to generate large dust outside the drill hole during the drilling process. The advantage of this principle is that typically the infiltration rate can be higher when the supply rate of the liquid components is low. A higher infiltration rate means more effective drilling and savings in time and money. Furthermore, the liquid components tanks on board the rock drill can be smaller.

[0033] According to one embodiment, the control unit is configured to control at least one control element for controlling the supply of the liquid component.

[0034] According to one embodiment, the control unit is configured to control at least one liquid component supply valve.

[0035] According to one embodiment, the control unit is configured to control at least one pump for controlling the supply of the liquid components, which pump can then function as the control element mentioned above.

[0036] According to one embodiment, the control unit can further control the supply of airflow according to the detected infiltration rate. The advantage of airflow control is that it can prevent dust overflow and spread. Moreover, if the size of the air can be adjusted according to the actual flushing need, significant energy savings can be achieved.

[0037] According to one embodiment, the control unit is configured to control an on-board compressor of the flushing system.

[0038] According to one embodiment, the control unit is configured to control the flow of air supplied from a compressed air line at a mine or work site.

[0039] According to one embodiment, the disclosed solution relates to a rock drilling rig, comprising a mobile carrier, at least one drilling boom movably mounted relative to the carrier, at least one drilling unit mounted to the at least one drilling boom and including a feed beam, a rock drill mounted to the feed beam, a drilling tool attachable to the rock drill, an air mist flushing system for supplying pressurized air and at least one liquid component into a drill hole, and an apparatus for controlling the air mist flushing system, the apparatus according to any one of the features and embodiments disclosed herein.

[0040] According to one embodiment, the rock drilling rig is provided with an on-board air mist flushing system. The rock drilling rig then includes a compressor for generating pressurized air, and further includes a tank and a pump for supplying the liquid components. The system further includes at least one liquid component supply channel provided with at least one supply valve for regulating the flow of the supplied liquid components.

[0041] According to one embodiment, the rock drilling rig is provided with a connection to a mine or work site water line, or a mine or work site compressed air line, or both.

[0042] According to one embodiment, one or more external flushing medium sources, such as external reservoirs and systems, can also be implemented in the disclosed solution. The supply system may be mobile.

[0043] According to one embodiment, the drilling unit comprises at least one detection device for detecting the penetration rate during drilling.

[0044] According to one embodiment, the rock drilling rig is provided with at least one detection device for detecting the moisture content of cuttings removed from the drilled hole during drilling.

[0045] According to one embodiment, the disclosed solution relates to a method for controlling flushing in rock drilling, the method comprising: using air mist flushing, where the flushing fluid comprises pressurized air and at least one liquid component, controlling the supply of air mist to the flushing system by at least one control unit during drilling, detecting a penetration rate of the drilling, and controlling the supply of the at least one liquid component of the air mist in response to the detected penetration rate and parameters input to the control unit.

[0046] According to one embodiment, the method further includes maintaining the moisture content of the flushed cuttings constant or substantially constant for each inspected drill hole despite varying infiltration rates during drilling of the drill hole.

[0047] According to one embodiment, the method further comprises providing to the control unit a selectable target moisture value for the moisture content of cuttings flushed from the wellbore during drilling.

[0048] According to one embodiment, the method further includes calculating in the control unit a volume of the removed and flushed solids of the cuttings for each period of time in response to data relating to the diameter of the drilling tool and the detected penetration rate, providing a target value to the control unit defining a relative amount between the liquid component of the air mist and the calculated volume of the solids of the cuttings, and controlling the supply of the liquid component in response to the target value.

[0049] According to one embodiment, the method further comprises providing a predefined data set to the control unit defining an acceptable moisture content of the cuttings and providing assistance to an operator on a user interface for selecting acceptable parameters for air mist flushing to be used in the drilling.

[0050] According to one embodiment the disclosed solution relates to a computer program product for controlling the supply of air mist for flushing in rock drilling, the computer program product comprising program code means configured to carry out the steps and procedures disclosed in claims 8 to 11 when executed on a computer or data processing device.

[0051] The above disclosed embodiments can be combined to form a suitable solution having the above mentioned characteristics required.

[0052] Some embodiments are explained in more detail in the accompanying drawings. [Brief description of the drawings]

[0053] [Figure 1] FIG. 1 is a schematic side view of a rock drilling rig for surface drilling, provided with a drilling unit and a system for flushing the drilling cuttings; [Diagram 2] FIG. 2 is a schematic diagram illustrating some of the features related to parameters in the disclosed flushing control. [Diagram 3] FIG. 1 is a schematic diagram of an apparatus for controlling air mist flushing. [Figure 4] FIG. 2 is a schematic diagram of some control parameters utilized in the apparatus of the present disclosure. [Diagram 5] FIG. 1 is a schematic diagram illustrating the disclosed control principle. [Figure 6] FIG. 2 is a schematic diagram showing possible liquid components of an air mist. [Figure 7] 1 is a schematic graph showing a flushing map.

[0054] For clarity, the figures show some embodiments of the disclosed solutions in a simplified manner. In the drawings, like reference numbers indicate like elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] FIG. 1 shows a rock drilling rig 1 intended for surface drilling. The rock drilling rig 1 comprises a mobile carrier 2 and at least one drilling boom 3 connected to the carrier 2. At the distal end part of the drilling boom 3 there is a drilling unit 4 with a feed beam 5 and a rock drill 6 supported thereon. A drilling tool 7 is connectable to the rock drill 6. At the front end of the rock drill 6 the rock drill 6 may comprise a shank adapter for connecting the tool 7. The rock drill 6 may comprise an impact device 8 and a rotation device 9. The rock drill 6 can be moved on the feed beam 5 by a feed device 10. At the distal end of the drilling tool 7 there is a drill bit 11. The drilling cuttings are flushed from the bottom of the drill hole 12 during drilling by conveying a flushing flow through the rock drill 6 and the drilling tool 7 to the bottom of the drill hole 12. The drilling tool 7 may comprise a tubular extension rod or tube, the inside of which is a flow path for the flushing medium. As the flushing medium flows through the drill bit 11, cuttings can be displaced from the drill hole.

[0056] In the disclosed solution, air mist flushing is performed. The carrier 2 may therefore include a compressor C for supplying pressurized air and a liquid component source L for supplying one or more liquid components to generate the desired flow and composition for the air mist. Alternatively or in addition, there may be a supply unit 13 for connecting the carrier 2 to one or more external sources of compressed air and liquid components. For clarity, tubes, hoses and other flow paths for conveying the flushing medium to the drilling unit 4 are not shown in FIG. 1. The air mist flushing system, as well as its devices and control elements, may be controlled by one or more control units CU. The control units CU may be provided with data on the infiltration rate and the moisture content of the cuttings. The infiltration rate may therefore be detected by one or more sensors S1 and, furthermore, there may be one or more moisture sensors S2 in association with the cuttings removal system 14.

[0057] FIG. 2 discloses that the penetration rate 15 and the moisture target value 16 are input to the control unit to control the supply of the liquid components. The system can compare the detected actual value 17 of the moisture content of the cuttings with the moisture target value 16 when generating the control signal. Alternatively, the system can calculate the removal rate 18 of the cuttings removed per period during drilling and compare the calculated data with the moisture target value 16. The removal rate can be calculated depending on data on the diameter of the drill bit, data on the density of the drilled rock material and the detected penetration rate. The diameter D of the drill bit 11 is shown in FIG. 3.

[0058] FIG. 3 discloses features of the disclosed cuttings moisture control system, the objective being to keep the moisture level of the removed cuttings 19 relatively constant despite possible variations in the infiltration rate 15 during the drilling of one drill hole 12. It is advantageous to implement the disclosed automatic flushing process and system in an automatic drilling process. An operator 20 can input the control parameters into the control unit CU by means of a user interface UI. The user interface UI can include one or more graphic elements 21 to assist in the provision of the parameters. For example, there may be a graphic element showing a selected moisture content target value. The target value can be shown to the operator visually and numerically, such as a percentage value. The graphic element 21 can show a tolerance range within which the desired value can be selected, so that the operator 20 is assisted or forced to make a rational choice in an intuitive way. The flushing can be indirectly controlled, since first the operator selects the desired moisture percentage of the cuttings, then the system calculates the amount of rock material removed during drilling, and finally the system calculates the amount of water or other liquid component required to achieve the set moisture percentage. Operation is easy for the operator, since only the target value needs to be input. The system keeps an eye on the rest of the controls and adjusts the flushing to possible external fluctuations.

[0059] The control unit CU is provided with one or more computer program products 22 or control algorithms which can be executed in a processor of the control unit CU. The control unit CU is configured to generate control signals CS which contain the necessary input control parameters and sensed data and which control the supply of at least the liquid component LC and possibly also the supply of the pressurized air PA. The control elements 23 may for example be pumps or valves.

[0060] FIG. 4 discloses some control parameters of the drilling and flushing process. The flushing parameters have already been disclosed above in this document. The drilling parameters may be feed parameters (speed, force), impact parameters (energy, frequency) and rotation parameters (speed, torque). In controlling the flushing, the drilling parameters are also taken into account. Furthermore, the drilling tool used may affect the flushing process control.

[0061] FIG. 5 shows in one combined presentation the moisture target level 24 [%], the infiltration rate 15 [m / min], the detected flow of the liquid component 25 [l / min] and the calculated moisture content of the drilling cuttings 26 [%]. The calculated moisture content 26 is calculated on the basis of data on the detected flow of the liquid component 25 and the detected infiltration rate 15. The arrow 27 indicates that the infiltration rate 15 is reduced by a factor external to the drilling control. The drilled rock may, for example, be changed to a harder one. If the infiltration rate is reduced, the calculated moisture content 26 increases, which causes the flushing control system to reduce the flow of the liquid component, as can be seen when examining the curve 25. A new equilibrium is then found. If the infiltration rate increases with the arrow 28, a reduction in the moisture content curve 26 occurs and, as can be seen when examining the curve 25, the system increases the supply flow of the liquid component. Again, a new equilibrium is found. The flushing system thus takes into account the change in the infiltration rate 15 and tries to bring the curve 26 closer to the set target level 24.

[0062] FIG. 6 discloses that the liquid component may have several alternative forms.

[0063] Figure 7 shows an example of a flushing map 29. The purpose of the flushing map 29 is to indicate permissible flushing parameter values. If the amount of liquid component in the air mist is too low, dust may be generated, so parameters in the dust generation area D should be avoided. If too much liquid component is used, clogging may occur. Therefore, operating parameters in the prohibited clogging area C1 must be avoided. There is also a second clogging area C2, in which clogging is possible, and that area should also be avoided if possible. Therefore, operating parameters that result in a situation between areas D and C1 and are marked with arrows 30 should be favored in the flushing control to achieve improved and problem-free flushing of the air mist. There may be customized flushing maps for different drilling tools and rock types.

[0064] The disclosed area can be defined as a data set in the control unit. Furthermore, the flashing map and the flashing parameters used can be displayed on the display of the rock drilling rig for the operator. In this way, valuable feedback can be provided to the operator.

[0065] The drawings and the associated description are intended only to illustrate the concept of the invention. In its details, the invention may vary within the scope of the claims.

Claims

1. A device for controlling air mist flushing of a rock drilling unit (4), said air mist comprising pressurized air (PA) and at least one liquid component (LC), The device comprises at least one control unit (CU) for controlling the supply of the air mist, The control unit (CU) is provided with data relating to the penetration rate (15) of the excavation, said control unit (CU) being adapted to generate a control signal (CS) for controlling the supply of said at least one liquid component (LC) of said air mist in response to input data relating to a penetration rate (15) and parameters input to said control unit (CU); The control unit is configured to receive an input target value (16) for moisture content of cuttings (19) removed from a drill hole (12) being drilled; The control unit: determining an actual moisture content of the cuttings (19); further configured to adjust the supply of said liquid component (LC) in response to a comparison of said input target value (16) with said actual value; the control unit (CU) is provided with detection data relating to the actual moisture (17) of the drilling cuttings removed from the drill hole (12), whereby a feedback control is provided, and the control unit (CU) is configured to control the supply of the liquid component (LC) in response to the input feedback data.

2. The control unit: calculating a removal rate of said removed cuttings (19) per period during said drilling in response to input data relating to a diameter (D) of a drill bit (11), data relating to a density of said drilled rock material, and said penetration rate (15); 2. The apparatus of claim 1, configured to calculate a required liquid component feed rate in response to the input target value (16) of moisture content and the calculated data on the removal rate of cuttings.

3. The flushing parameters input to the control unit (CU) include a data set relating to an allowable moisture value for the moisture content of the cuttings; 2. The device according to claim 1 , characterized in that

4. said control unit (CU) being configured to automatically select such control parameters from said data set relating to acceptable moisture values ​​that minimize the supply of liquid components; 4. The device according to claim 3 .

5. The control unit (CU) is configured to control at least one liquid composition control element (23), 2. The device according to claim 1 , characterized in that

6. The control unit (CU) is further configured to control the supply of air flow in response to the detected permeation rate (15).

2. The device according to claim 1 , characterized in that

7. A rock drilling rig (1), comprising: A movable carrier (2); at least one excavation boom (3) movably mounted relative to the mobile carrier (2); at least one drilling unit (4) mounted on said at least one drilling boom (3) and including a supply beam (5); a rock drill (6) mounted on said supply beam (5); and a drilling tool (7) attachable to said rock drill (6); an air mist flushing system for supplying pressurized air (PA) and at least one liquid component (LC) into the drilled hole (12); and a device for controlling the air mist flushing system, The device is a device according to any one of claims 1 to 6. A rock drilling rig (1).

8. 1. A method for controlling flashing in rock drilling, comprising: Using air mist flushing, the flushing fluid comprising pressurized air (PA) and at least one liquid component (LC); receiving a target moisture value (16) for the moisture content of cuttings (19) flushed from a wellbore (12) during drilling; controlling the supply of said air mist to a flushing system by at least one control unit (CU) during said drilling; Detecting the penetration rate (15) of the excavation; and controlling the supply of said at least one liquid component (LC) of said air mist in response to said detected permeation rate (15) and parameters input to said control unit (CU), Determining an actual moisture content of the cuttings (19); adjusting the supply of said liquid component (LC) in response to a comparison of said input target moisture value (16) with said actual value; receiving detection data relating to an actual moisture content (17) of the cuttings removed from the drill hole (12), whereby feedback control is provided to the control unit (CU); controlling the supply of the liquid component (LC) in response to the input feedback data; The method is characterized by:

9. maintaining a constant moisture content of cuttings (19) flushed from a drill hole (12) for each drill hole (12) inspected despite changes in infiltration rate (15) during the drilling of said drill hole (12); The method according to claim 8, characterized by:

10. Calculating in said control unit (CU) the volume of solids of the removed and flushed cuttings (19) per period in response to data relating to the diameter (D) of the drilling tool (7, 11) and said detected penetration rate (15); providing said control unit (CU) with a target value (16) defining the relative amount between the liquid component (LC) of said air mist and a calculated volume of solids of said cuttings (19); controlling the supply of the liquid component (LC) in response to the target value (16); The method according to claim 8, characterized by:

11. providing said control unit (CU) with a predefined data set defining an allowable moisture content of said cuttings (19); providing assistance to an operator (20) on a user interface (UI) for selecting acceptable parameters for the air mist flushing to be used in the drilling; The method according to claim 8, characterized by:

12. A computer program product (22) for controlling the supply of air mist flushing in rock drilling, said computer program product (22) comprising program code means configured to perform the steps and procedures disclosed in any one of claims 8 to 11 when said computer program product (22) is executed on a computer or data processing device.

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