Patent Application
20240209701
The invention relates to an apparatus for controlling air mist flushing of a rock drilling unit in rock drilling. The air mist comprises pressurized air and one or more liquid components. The air mist is used for flushing the drilled holes.
The invention further relates to a rock drilling rig, and to a method and computer program product for controlling the air mist flushing system.
The field of the invention is defined more specifically in the preambles of the independent claims.
In mines and at other work sites different type of rock drilling rigs are used for drilling drill holes to rock surfaces. The rock drilling rigs are provided with one or more booms and rock drilling machines are arranged at distal ends of the booms. During the drilling dust and larger sized drilling cuttings are formed and there is need to remove them from the drill holes. Therefore, the drilling machine is provided with a flushing device for feeding flushing fluid inside the drill hole via the drilling tool. The flushing media may be air, water, or mist. There are different solutions for controlling the flushing process and feeding of the flushing fluid. However, the known solutions have shown some disadvantages.
An object of the invention is to provide a novel and improved apparatus, method and computer program product for controlling air mist flushing, and further to provide a novel and improved rock drilling rig utilizing the disclosed solutions.
The apparatus according to the invention is characterized by the characterizing features of the first independent apparatus claim.
The rock drilling rig according to the invention is characterized by the characterizing features of the second independent apparatus claim.
The method according to the invention is characterized by the characterizing features of the independent method claim.
The computer program product according to the invention is characterized by the characterizing features of the third independent apparatus claim.
An idea of the disclosed solution is that the apparatus comprises one or more control units for controlling feeding of the air mist comprising pressurized air and one or more liquid components. The control unit is provided with data on penetration rate of drilling. Thereby, the control unit generates control signals for controlling feeding of the one or more liquid components of the air mist in response to the input data on penetration rate. The control unit may also be provided input parameters affecting to executed flushing control.
In other words, moisture content of the fed air mist is adjusted in relation to the data on penetration rate. The penetration rate means progression of a drill bit into the rock in a certain period of time. Typically, the pene—tration rate is expressed m/min.
The aim of the disclosed solution is to affect to properties of drilling cuttings, removed by the flushing from the drill hole, predominantly by adjusting the amount of the liquid content in the air mist. Further, the purpose is to keep the moisture level of the removed drilling cuttings relative constant despite of possible variations in the penetration rate during drilling of one drill hole. Then the system can react to varying rock characteristics and other external variations, for example.
An advantage of the disclosed solution is that clogging of drilling cuttings and other problems can be avoided when the amount of the liquid content and other flushing parameters in the air mist are adjusted properly. Too high level of moisture may cause clogging. On the other hand, when the level of moisture is too low, then dust may cause significant problems. In this solution the moisture-based flushing not only prevents the clogging and dusting problems but may also save energy and flushing media, and further, may ensure full drilling efficiency and allows to keep the working site and the rock drilling rig cleaner.
Further, the disclosed operator-free flushing control suits well for unmanned drilling processes and remote controlled drilling.
According to an embodiment, the penetration rate can be determined in versatile ways and by means of different sensing means. It is possible to sense movement of a rock drilling machine on a feed beam of the rock drilling unit by means of one or more sensors or sensing devices. Alternatively, it is possible to sense operation of a feed device and to determine for example flow rate of hydraulic fluid fed to a feed cylinder of the drilling unit and to determine the penetration rate on the basis of the sensed flows.
According to an embodiment, the feeding of the liquid component is adjusted automatically when the penetration rate varies due to external factors, such as changes in rock quality. The penetration rate may indicate indirectly rock quality, whereby the moisture content is controlled indirectly in response to rock characteristics.
According to an embodiment, the disclosed solution may also detect drilling parameters selected by the operator and may control the feeding of the liquid component based on that. The operator may decrease penetration rate of the drilling by decreasing impact pressure of an impact device, for example, and may thereby try to improve straightness of the drilled holes when drilling demanding rock. The system may monitor the input drilling parameters and may execute required control for the flushing.
According to an embodiment, the liquid component may be water, water solution or any suitable liquid mixture. According to an embodiment, the control unit is configured to examine each drill hole separately and to execute the disclosed adjustment measures case-by-case for each drill hole. In other words, the control unit is configured to examine each drill hole gradually as the drilling advances and executes the disclosed adjustment measures accordingly.
According to an embodiment, the control unit may be provided with input target value for moisture content of drilling cuttings removed from the drill hole being drilled. The control unit may also determine real value of moisture content of the drilling cuttings and may then compare the input target value and the real value and may adjust feeding of the liquid component on the basis of the comparison.
According to an embodiment, the control unit is configured to communicate with at least one user interface. An operator may input desired target values to the control unit by means of the user interface.
According to an embodiment, the mentioned user interface may comprise a visual display element or graphical element for inputting the target values. The visual or graphical display element may be intuitive and may improve user friendliness.
According to an embodiment, the input target value and real value are relative values.
According to an embodiment, the input target value and real value are percentage values. Thus, the values under examination are percentages of moisture.
According to an embodiment, the control unit is configured to: calculate removal rate of the removed drilling cuttings per time period during the drilling in response to input data on diameter of a drill bit, data on density of the drilled rock material and the penetration rate; calculate required liquid component feed rate in response to the input target value for moisture content and the calculated data on the removal rate of drilling cuttings. In other words, the control unit is configured to determine the real value of the moisture content by means of calculation process. Then, there is no need to provide the control unit with sensing data on the real moisture amount. Thus, in this embodiment an indirect control principle is implemented.
According to an embodiment, the calculated removal rate of the flushed drilling cuttings per time period during the drilling may be called a volumetric penetration rate, since it indicates amount of volume of removed solid rock per time period. Feeding of the pressurized air and the liquid component needs to be adjusted in response to the detected volumetric penetration rate so that the preferable moisture content values can be reached.
According to an embodiment, the control unit is provided with input data on density of the rock material to be drilled, or alternatively, the control unit is provided with sensing data during the drilling 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 a suitable algorithm for executing calculation or determination of the density.
According to an embodiment, the control unit is provided with sensing data on the real moisture of the drilling cuttings removed from the drilled hole, whereby the control unit is provided with feedback control and is configured to control the feeding of the liquid component in response to the input feedback data. In this embodiment there are one or more sensors or sensing devices arranged to sense the moisture of the cuttings. The sensors may be arranged in connection with a dust collection system, for example.
According to an embodiment, the disclosed solution comprises flushing parameters input to the control unit, and the input control parameters comprise data sets on allowed moisture values of moisture content of the drilling cuttings. The allowed moisture values may be determined in practical test and measurements. Further, the data sets may be customized for different drilling situations, rock types, drilling tools, for example.
According to an embodiment, the control unit is configured to prevent control situations wherein the feeding of the liquid component leads to air mist flushing situations outside the allowed moisture values defined by the input data sets.
According to an embodiment, the allowable flushing parameters or data sets are illustrated by means of predefined flushing maps. There may be different flushing parameters and flushing maps which are based on practical studies made for different rock characteristics and drilling tools, for example.
According to an embodiment, the control unit may automatically select such control parameters from the data set on allowed moisture values which minimize feeding of liquid component. In other words, this embodiment utilizes as low moisture content as possible but still takes care of that no significant dusting occurs outside the drill hole during the drilling process. An advantage of this principle is that typically the penetration rate can be higher when the feeding rate of the liquid component is low. The higher penetration rate means more effective drilling and savings in time and expenses. Further, liquid component tanks onboard the rock drilling machine may then be smaller.
According to an embodiment, the control unit is configured to control at least one control element for controlling feeding of the liquid component.
According to an embodiment, the control unit is configured to control at least one liquid component feed valve.
According to an embodiment, the control unit is configured to control at least one pump for controlling feeding of the liquid component. The pump may then serve as the above mentioned control element.
According to an embodiment, the control unit may additionally control feeding of air flow in response to the detected penetration rate. An advantage of the air flow control is that an overflow and spreading of dust can be prevented. Further, remarkable energy savings can be achieved when magnitude of the air can be adjusted according to the actual flushing need.
According to an embodiment, the control unit is configured to control an onboard compressor of a flushing system.
According to an embodiment, the control unit is configured to control air flow supplied from a compressed air line of a mine or work site.
According to an embodiment, the disclosed solution relates to a rock drilling rig. The rock drilling rig comprises: a movable carrier; at least one drilling boom mounted movably relative to the carrier; at least one drilling unit mounted to the at least one drilling boom and comprising a feed beam; a rock drilling machine mounted on the feed beam and a drilling tool mountable to the rock drilling machine; an air mist flushing system for feeding pressurized air and at least one liquid component into a drill hole; and an apparatus for controlling the air mist flushing system. The apparatus is in accordance with any one of the features and embodiments disclosed in this document.
According to an embodiment, the rock drilling rig is provided with an onboard air mist flushing system. Then the rock drilling rig comprises a compressor for generating the pressurized air, and further, there is a tank and a pump for feeding the liquid component. The system further comprises at least one liquid component feed channel provided with at least one feed valve for adjusting flow of the fed liquid component.
According to an embodiment, the rock drilling rig is provided with connection to a water supply line of a mine or work site, or to a compressed air line of the mine or work site, or to both.
According to an embodiment, one or more external flushing media supply sources, such as external reservoirs and systems can also be implemented in the disclosed solution. The supply systems may be mobile.
According to an embodiment, the drilling unit is provided with at least one sensing device for detecting penetration rate during the drilling.
According to an embodiment, the rock drilling rig is provided with at least one sensing device for detecting moisture content of drilling cuttings: removed from the drilled hole during the drilling.
According to an embodiment, the discloses solution relates to a method of controlling flushing in rock drilling. The method comprises: using air mist flushing wherein flushing fluid comprises pressurized air and at least one liquid component; controlling during the drilling feeding of the air mist to a flushing system by means of at least one control unit; detecting penetration rate of the drilling; and controlling feeding 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.
According to an embodiment, the method further comprises keeping moisture content of flushed drilling cuttings constant or substantially constant for each examined drill hole despite of varying penetration rate during the drilling of the drill hole.
According to an embodiment, the method further comprises providing the control unit with a selectable target moisture value for moisture content of drilling cuttings flushed away from the drill hole during the drilling.
According to an embodiment, the method further comprises calculating in the control unit volume of solid matter of the removed and flushed drilling cuttings per time period in response to data on diameter of a drilling tool and the detected penetration rate; providing the control unit with a target value defining relative amounts between the liquid component of the air mist and the calculated volume of solid matter of the drilling cuttings; and controlling the feeding of the liquid component in accordance with the target value.
According to an embodiment, the method further comprises providing the control unit with predetermined data sets defining allowed moisture content of the drilling cuttings; and providing, on a user interface, an operator with assistance for selecting allowable parameters for the air mist flushing used in the drilling.
According to an embodiment, the disclosed solution relates to a computer program product for controlling feeding of air mist flushing in rock drilling. The computer program product comprises program code means configured to execute the steps and procedures disclosed in the previous claims when being run on a computer or a data processing device.
The above disclosed embodiments may be combined in order to form suitable solutions having those of the above features that are needed.
Some embodiments are described in more detail in the accompanying drawings, in which
For the sake of clarity, the figures show some embodiments of the disclosed solution in a simplified manner. In the figures, like reference numerals identify like elements.
In the disclosed solution air mist flushing is implemented. Therefore, the carrier 2 may be provided with a compressor C for feeding pressurized air, and a liquid component source L for feeding one or more liquid components, for producing desired flow and composition for the air mist. Alternatively, or in addition to, there may be a feed unit 13 for connecting the carrier 2 to one or more external sources of compressed air and liquid components. For clarity reasons tubes, hoses and other flow channels for conveying the flushing media to the drilling unit 4 are not shown in
The control unit CU is provided with one or more computer program products 22 or control algorithms which may be executed in a processor of the control unit CU. The control unit CU is provided with required input control parameters and sensing data, and is configured to generate control signals CS for one or more control elements 23 controlling at least the feeding of the liquid component LC, and possibly also controlling feeding of the pressurized air PA. The control element 23 may be a pump or valve, for example.
The disclosed areas may be defined as data sets for the control unit. Further, the flushing maps and the used flushing parameters may be shown on display device of a rock drilling rig for the operator. This way valuable feed back can be provided for the operator.
The drawings and the related description are only intended to illustrate the idea of the invention. In its details, the invention may vary within the scope of the claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 21171309.4 | Apr 2021 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/060503 | 4/21/2022 | WO |
