TECHNICAL FIELD OF THE INVENTION

The invention relates to a device and method for cleaning a rock sample, such as the rock sample drilled from a bedrock. In particularly, the invention relates to a device and method for removing residues from a surface of the rock sample, such as residues from or due to a drilling the rock samples. The residues may contain e.g. residues both from the rock sample or bedrock itself, but also from the drilling process, such as from cooling liquid used for cooling a drill bit as well as particles from the drill bit when it wears out, or additional or extra substances.

BACKGROUND OF THE INVENTION

Conventionally the residues from the rock samples are cleaned or removed by a brush, pressurised air and/or soaking.

However, there are problems related to the conventional methods, namely e.g. the particle size of the residues may be so small that the residues may got stuck into a porous structure of the sample and it is impossible to get the residues away by the brush or pressurised air, or even soaking. In addition, the soaking will wet the sample and liquid used will diffused into a deeper structure of the sample. Still in addition, quality is either uneven or at least the uniformity of the quality is very challenging to achieve. Further, the liquids used for soaking may be environmentally unfriendly. Moreover, the conventional methods, such as chemicals, may even unintentionally add additional or extra substances.

SUMMARY OF THE INVENTION

An object of the invention is to alleviate and eliminate the problems relating to the known prior art. Especially the object of the invention is to provide a fast and accurate device and method for cleaning the samples, so that the residues or other extra substances can be effectively removed and in addition so that the quality is high and uniform.

The object of the invention can be achieved by the features of independent claims.

The invention relates to a device for cleaning a rock sample according to claim 1. In addition, the invention relates to a method for cleaning a rock sample according to claim according to claim 13.

According to an embodiment a device for cleaning a rock sample comprises a laser beam directing device for outputting and directing a laser beam to a surface of the rock sample to exposure and remove residues or other extra substances (residues hereinafter) from the surface of the rock sample. The residues are originated for example from or due to drilling the rock samples for example from a bedrock. Ingredients of the residues are both from the rock sample or bedrock itself, but also from the drilling process, such as cooling liquid used for cooling a drill bit as well as particles from the drill bit when it wears out during drilling.

In addition, the device comprises also a control unit for selecting parameters for the output laser beam of the laser beam directing device so that said parameters are most appropriate to said rock samples in question. Thus, the parameters are selected based on a type of said rock sample and/or the residues and are used for controlling the laser beam of said laser beam directing device. The parameters of the laser beam to be controlled may be for example wavelength, power, amplitude, exposure time or polarization, just as examples and not limiting to those only.

It is to be noted that laser beam directing device may also comprise a laser source, or alternatively the laser beam directing device is coupled with a separate laser source, whereupon the laser source can be controlled by the control unit of the invention.

The rock sample is typically an elongated cylinder drilled from the bedrock. Due to drilling the surface or surface layer of the rock sample contains residues, which might be stuck into a porous structure of the sample. The laser beam with appropriate parameters will cause, according to the embodiments of the invention, plasma reactions on the surface structure of the rock sample and in the residual particles. With suitable parameters, such as wavelength and amplitude, also a resonance or vibration may be achieved, whereupon the residual particles can be released from the microstructure of the rock sample due to resonance and without making harmful effects to rest of the rock sample.

In addition, it is to be noted that the rock sample can be cleaned by the laser beam in the direction of the longitudinal axis of the elongated sample. It is a desired effect to remove at least a trail of the residuals in the direction of the longitudinal axis of the rock sample so that later the content or composition of the rock sample can be analysed by an analysing device, such as analysing whether the rock sample comprises noble metals or other minerals or elements. Without cleaning by the laser according to the invention, the possible materials, or components to be sought may be located behind or under the residuals, whereupon the analysing device is not able to detect them.

According to an embodiment the device comprises a first detecting device for detecting changes in the surface of the rock sample, when at least one parameter, such as power or wavelength, of the laser beam exposed to the surface of the rock sample is varied. The detecting device may e.g. comprise two cameras or the like, where the first camera detects and outputs first data of the surface of the rock sample before exposed by the laser and the second camera detects and outputs second data of the surface of the rock sample after exposed by the laser. Thus, determining the differences between the first camera and second camera outputs the changes in the surface of the rock sample due to the laser beam exposure (and due to varied parameter of the laser beam) can be determined. The determination can be done either by the detecting device as such, or by the control unit or other external device. For example, a threshold value can be set to the difference between the first camera and second camera outputs so that when the laser beam produces sufficient cleaning effect (with certain parameters) the threshold value is also achieved and the parameters can be set.

According to an embodiment the device may comprise a second detecting device for detecting and determining at least one property of the surface of the rock sample before and after the exposure. The property of the surface of the rock sample is e.g. density, gloss, magnetism, radioactivity, colour, transparency, refractive index, birefringence, contrast, fluorine and phosphorescence, brittleness, wear, hardness, elasticity, chemical properties, or combination of those, or the like, not limiting to those examples only. The detecting device outputs data related to the determined property of the surface of the rock sample before and after said exposure, whereupon the control unit determines and adjusts the parameters to be used, so via trial and error. For example, the laser beam may clean the same point or area number of times and when there is no changes exceeding a predetermined limit, the sample can be kept clean or residues removed enough.

According to an embodiment the device comprises a third detecting device for detecting a composition of residues removed and when changes of the composition of the residues removed is within a certain predetermined limit, and thus essentially no residues is removed anymore, the sample can be kept clean enough. The device ay e.g. comprise suction means for sucking up the removed residues, whereupon the third detecting device can detect the removed residues sucked by the suction device.

According to an embodiment the device comprises a fourth detecting device for detecting the type of the rock sample e.g. via determining at least one property of the rock sample, such the propertied discussed elsewhere in this document. The fourth detecting device may then output data related to the type of the rock sample to the controlling unit. In addition, the device or an arrangement may have a database, or the database may be an external database, which comprises a library of the rock sample type and corresponding parameters to be used for a particular rock sample type for cleaning. The controlling unit may then select at least one parameter for the output of the laser beam directing device based on the data related to the type of the rock sample from the database comprising relations between rock samples and parameters to be used.

It is to be understood that also the user can manually input the parameters, if the rock sample or the parameters is otherwise known.

In addition, the device may also comprise a fifth detecting device for detecting amount or depth of a layer of the residues removed and for outputting a parameter describing the detected amount or depth to the control unit. The control unit may then control the at least one parameter of the laser beam directing device, speed of the mutual moving of the laser and the rock sample, and/or parameters of the laser beam based on the parameter outputted by the detecting device in order to remove desired amount or depth of the residues from the surface of the rock sample. According to an embodiment at least one of the detecting devices can be implemented by a camera, but it is to be noted that any device known by the skilled person for detecting the type of the rock sample or the surface of the rock sample, can be used. In particular, the detecting device can determine reflections, brightness changes, colours and the like from the surface of the rock sample. In addition, when determining the changes on the surface of the rock samples, also other devices can be used, such as laser scanning devices and laser point cloud-based systems known from prior art for detecting especially 3D changes or other changes due to removed residues.

According to an embodiment the device comprises a moving device configured to move the laser beam directing device and the rock sample in relation to each other for exposing the surface of the rock sample by the laser beam. The control unit advantageously controls the movement so that the exposure time per certain unit of length of the rock sample is as selected by said control unit, or so that a certain portion can be manipulated or exposed multiple times, so moving the sample back and forth.

The device may comprise a laser source or there may be also an external laser source. The device may comprise a laser beam input for receiving the laser beam and a laser beam guiding device to guide the laser beam from the laser beam input to the laser beam directing device and suitable devices to collimate and focus the laser beam to the surface of the rock sample.

The laser source or type of the laser beam can be selected or changed based on the need. Typically, according to the invention, the laser beam and its parameters are selected so that the laser beam provides plasma reactions in the residues or on the surface of the rock sample. Advantageously the laser beam and its parameters are selected so that the beam provides resonance and vibration so that the residual particles can be released from the microstructure of the rock sample due to resonance. In addition, the laser beam heats the surface and residues, whereupon the removed residual particles (a cloud of dust) are moved away from the surface by a convection. It is to be noted, that also a suction device and/or fan can be used to move the removed residual particles away from the surface.

According to an embodiment the device may also comprise additionally a second laser beam directing device for outputting and directing a second laser beam to the surface of the rock sample to exposure and remove said residues from the surface of the rock sample after the first laser beam, and wherein at least one parameter for said second laser beam is determined and selected after said first laser beam.

According to an embodiment the device may also comprises a focusing or targeting laser for targeting an area to be cleaned so that the laser beam used for cleaning can be targeted e.g. automatically, e.g. by the help of machine vision, for example.

The present invention offers advantages over the known prior art, such as enables very easy, simple, reliable, and fast way to clean the rock samples. In particularly, by the current invention the residues can be effectively removed, with high quality and so that the quality is very uniform. In addition, there is no risk that the removing of residues according to the invention would unintentionally add any additional substances to the rock sample to be cleaned. Thus, after the cleaning the composition and ingredients of the rock sample can be easily and accurately detected by a composition detection device.

The present invention offers very environmentally friendly as well as accurate device and method for cleaning the rock samples. In addition, the device can be self-employed and automated, as well as self-learning.

The exemplary embodiments presented in this text are not to be interpreted to pose limitations to the applicability of the appended claims. The verb "to comprise" is used in this text as an open limitation that does not exclude the existence of also unrecited features. The features recited in depending claims are mutually freely combinable unless otherwise explicitly stated.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific example embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS Next the invention will be described in greater detail with reference to exemplary embodiments in accordance with the accompanying drawings, in which:

Figures 1-2 illustrate exemplary devices for cleaning a rock sample according to an advantageous embodiment of the invention.

DETAILED DESCRIPTION

Figures 1 illustrates an exemplary device 100 for cleaning a rock sample 101 according to an advantageous embodiment of the invention, where the device 101 comprises a laser beam directing device 102 for outputting and directing a laser beam 103 to a surface 104 of the rock sample 101 to exposure and remove residues 105 from the surface of the rock sample.

In addition, the device comprises also a control unit 106 for selecting parameters for the output laser beam 103.

It is to be noted that laser beam directing device may also comprise a laser source 107, or alternatively the laser beam directing device is coupled with a separate laser source 108, whereupon the laser source can be controlled by the control unit 106.

The device may comprise a first detecting device 111 for detecting changes 109 in the surface 104 of the rock sample 101 . The detecting device may e.g. comprise two cameras or the like, where the first camera detects and outputs first data of the surface of the rock sample before exposed by the laser and the second camera detects and outputs second data of the surface of the rock sample after exposed by the laser.

The device may comprise a second detecting device 112 for detecting and determining at least one property of the surface of the rock sample before and after the exposure. The detecting device 112 outputs data related to the determined property of the surface of the rock sample before and after said exposure, whereupon the control unit 106 determines and adjusts the parameters to be used.

The device may comprise a third detecting device 1 13 for detecting a composition of residues 105 removed and when changes of the composition of the residues removed is within a certain predetermined limit, and thus essentially no residues is removed anymore, the sample can be kept clean enough. The device ay e.g. comprise suction means 110 for sucking up the removed residues, whereupon the third detecting device 113 can detect the removed residues sucked by the suction device.

The device may comprise a fourth detecting device 114 for detecting the type of the rock sample e.g. via determining at least one property of the rock sample. The fourth detecting device 114 may then output data related to the type of the rock sample to the controlling unit 106.

The device or an arrangement may have a database 116, or the database may be an external database 116, which comprises a library of the rock sample type and corresponding parameters to be used for a particular rock sample type for cleaning. The controlling unit 106 may then select at least one parameter for the output of the laser beam directing device based on the data related to the type of the rock sample from the database comprising relations between rock samples and parameters to be used.

The device may comprise a fifth detecting device 115 for detecting amount or depth of a layer 109 of the residues 105 removed and for outputting a parameter describing the detected amount or depth to the control unit 106. The control unit 106 may then control the at least one parameter of the laser beam directing device, speed of the mutual moving of the laser and the rock sample, and/or parameters of the laser beam based on the parameter outputted by the detecting device in order to remove desired amount or depth of the residues from the surface of the rock sample.

The device may also comprise a moving device 117 configured to move the laser beam directing device and the rock sample in relation to each other for exposing the surface of the rock sample by the laser beam. The control unit 106 advantageously controls the movement.

It is to be noted that the third detecting device 113 for detecting a composition of residues 105 removed is advantageously arranged in connection with the device, such as suction device 110 for sucking up the removed residues, whereupon the third detecting device 113 can detect the removed residues sucked by the suction device effectively, as is illustrated in Figure 2.

The invention has been explained above with reference to the aforementioned embodiments, and several advantages of the invention have been demonstrated. The invention is not only restricted to these embodiments but comprises all possible embodiments within the spirit and scope of the inventive thought and the following patent claims. The features recited in dependent claims are mutually freely combinable unless otherwise explicitly stated.