Device, drilling rig and method for detecting water in a material flow

Abstract

A device (1) for detecting water in a material flow (20) during drilling, wherein the device (1) comprises a control unit (2), a data acquisition unit (3) and a sensor (4), wherein the sensor comprises at least two probes (5), wherein the at least two probes (5) are arranged in contact with the material flow and connected to a programmable voltage source and a programmable voltage receiver. The device is configured to: - measure the ratio between the received voltage waveform and the applied voltage waveform for a set of predetermined frequencies; - determine the complex impedance between the at least two probes (5) for each of the predetermined frequencies based on the measured ratio; - determine a set of time averages of the complex impedance determined for each of the predetermined frequencies using a time window; - determine a set of standard deviations based on the determined time averages; and - indicate the detection of water when at least one of the standard deviations exceeds a threshold condition.

Description

Technical Field

[0001] The present invention relates to the field of mining industry, such as rock crushing or rock drilling. In particular, the present invention relates to detecting water in a material flow while drilling. Background Art

[0002] Rock drilling or rock breaking is nowadays widely used in many industries such as oil, gas, well drilling, mining, infrastructure construction and civil engineering. Many different drilling techniques are used such as rotary percussion drilling and rotary drilling. The choice of drilling technique depends on the specific application, among which the type of rock formation, the depth and the diameter of the borehole are important.

[0003] During drilling, for example in rock, a material flow is generated. The material flow may include cut stone particles, but may also include dust and / or sand. Filters may be used to separate the cut stone particles, dust and / or sand from the air. In case water is present in the material flow, these particles and the water may form a solidified layer on the filter, which requires frequent filter replacement. Therefore, it is useful to detect water in the material flow during drilling. With the goal of remotely commanding a drilling unit, automatic water detection is required.

[0004] US 8076950 B2 discloses a method for determining the water conductivity and water volume fraction of a multi-component mixture of water and at least one additional liquid or gas in a pipeline. The method is based on the measurement of the complex dielectric constant of the multi-component mixture, which is determined by measuring the wave phase constant of a plane electromagnetic wave propagating near the inner wall of the pipeline. The measurement of the wave phase constant is based on the measurement of the phase difference between two receiving antennas located in the pipeline at different distances from a third transmitting antenna. The phase measurement is performed at at least two frequencies in the range between 10 MHz and 10 GHz. The method presents high to medium water content, where the water contamination in the material flow is too low to affect the phase velocity in the medium in a detectable way. Worse still, water bound to solid particles will not exhibit the usual dielectric behavior described by a relative dielectric function value of about 60 to 80. The bound water will not exhibit a relative dielectric function greater than 2 to 5. The phase measurement of the bulk dielectric behavior is not very sensitive.

[0005] US 7679375 B2 discloses a method for detecting foreign matter in a product. The method responds to rapid changes in the dielectric composition of a material flow. The measurements are made in transit and the results are not used to calculate the dielectric function of the material, but are depicted as a Poincaré curve. This curve will include the scattered signals of small objects. The purpose of the method is to detect objects that are smaller than the wavelength of the radar signal used and to detect objects with a lower dielectric function than the dielectric function of the surrounding environment.

[0006] WO 2006052202 A1 relates to a method for determining a physical parameter (e.g. temperature or density) inside an object by determining the dielectric function of the object. For this method, the coherent and simultaneous application of ultrasound and microwave signals requires an alternating application of microwave signals, with the effect that nonlinear material properties start to be visible. Therefore, it is necessary to ultrasonically induce density changes in the material. Such ultrasound-induced density changes require an inelastic medium. Therefore, the method is not suitable for systems containing air.

[0007] WO 0218920 A1 discloses a method and a device for measuring the distribution of selected properties in a substance, and in particular a device for non-contact and non-destructively measuring the spatial distribution of a property of a substance, such as density, water content and temperature of the substance, by detecting electromagnetic radiation.

[0008] None of the above methods present a viable solution for measuring sufficiently low water levels required to prevent filter clogging. The water levels being processed are so low that volumetric measurements of any property changes are not feasible. Additionally, natural changes in the volumetric properties of the material stream (e.g., changes in stone characteristics or density) will be much more noticeable than the presence of water. Therefore, there is a need for improvements in this area of ​​the art. Summary of the invention

[0009] The purpose of embodiments herein is to enhance water detection performance in a material flow during drilling, or at least to enable an alternative to known solutions in the art.

[0010] According to one aspect, the object is achieved by providing a device suitable for detecting water in a material flow during drilling. The device comprises a control unit, a data acquisition unit and a sensor. The sensor comprises at least two probes. The at least two probes are to be arranged in contact with the material flow and connected to a programmable voltage source and a programmable voltage receiver. The device is configured to measure the ratio between the received voltage and the applied voltage for a set of predetermined frequencies. The device is also configured to determine a set of complex impedances between the at least two probes for each of the set of predetermined frequencies based on the measured ratio. The device is also configured to determine a set of time averages of the complex impedances determined for each of the predetermined frequencies using a time window. The device is also configured to determine a set of standard deviations based on the determined time averages. The device is also configured to indicate that water is detected when at least one of the standard deviations exceeds a threshold condition.

[0011] According to another aspect, the above object is also achieved by providing a method for detecting water in a material flow during drilling. The method includes: measuring a ratio between a received voltage waveform and an applied voltage waveform for a set of predetermined frequencies. The method also includes: determining a set of complex impedances between at least two probes for each of the set of predetermined frequencies based on the measured ratio. The method also includes: using a time window to determine a set of time averages of the determined complex impedances. The method also includes: determining a set of standard deviations based on the determined time averages. The method also includes: indicating that water is detected when at least one of the standard deviations exceeds a threshold condition.

[0012] Also provided herein is a drilling rig comprising an apparatus for detecting water in a material flow.

[0013] By arranging at least two probes in contact with a material flow during drilling, and measuring the ratio between a received voltage and an applied voltage, a complex impedance between the probes can be determined for each of the predetermined frequencies based on the measured ratios. And by determining a set of time averages of the determined complex impedances and determining a set of standard deviations based on the determined time averages, when at least one of the standard deviations exceeds a threshold condition, detection of water can be indicated. Thus, the water detection performance in a material flow during drilling is enhanced and more optimized. The more optimized and enhanced water detection performance will result in reduced wear of the filter, and the filter will not need to be replaced as frequently.

[0014] Thus, a method and apparatus for detecting water in a material flow during drilling is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Other objects, advantages and technical features of the present invention will become apparent from the following description of one or several embodiments given with reference to the accompanying drawings, in which:

[0016] Figure 1 is a schematic overview of an exemplary apparatus arranged on a drilling rig for detecting water in a material flow during drilling;

[0017] Figure 2 is a schematic diagram of an exemplary apparatus for detecting water in a stream of material during drilling; and

[0018] Figure 3 is a flow chart illustrating a method for detecting water in a material flow during drilling.

[0019] It should be noted that the drawings are not necessarily drawn to scale and that the dimensions of certain elements may be exaggerated for the sake of clarity. DETAILED DESCRIPTION

[0020] The invention is described in more detail below with reference to the accompanying drawings, in which examples of implementation are shown. The invention is not limited to the examples of implementation described; rather, the invention is defined by the appended patent claims. Throughout the text, like reference numerals in the drawings refer to like elements.

[0021] Figure 1 A schematic overview of an embodiment herein is shown, comprising a device 1 suitable for detecting water in a material flow during drilling, e.g. rock drilling. The device 1 is placed on a drilling rig 10, in a material flow 20, in front of a filter 30 (e.g. a material filter for separating cut stone particles, dust and / or sand from air).

[0022] exist Figure 2 2 shows a device 1 for detecting water in a material flow 20 during drilling. The device 1 comprises a control unit 2, a data acquisition unit 3 and a sensor 4. The device 1 may also comprise a remote unit 6 to repeat the indication of the detection of water to a drilling rig operator.

[0023] The material flow 20 (which may also be referred to as a drilling cutting flow, a drilling flow or a material return flow) is a returned drilling flow and may, for example, include a gas component mainly composed of air, a group of solid components including sand, dust and stone particles, a group of liquid components in which water is present and / or a group of dissolved components in the liquid.

[0024] The control unit 2 may be, for example, a controller such as a microcontroller, a microprocessor, a data logger unit or other digital hardware, which is configured to perform the method herein. The control unit 2 includes a display indicating the system status and a connection button for restarting or manually performing water presence detection. The data acquisition unit 3 may be, for example, a compact signal generator.

[0025] The data acquisition unit 3 is completely galvanically separated from the probe 5. This is a requirement to avoid damage and destruction of the electronics in a dry environment where the material flow 20 would statically charge the sensor head. Therefore, the device 1 is also suitable for dielectric or piezoelectric rock types that are prone to charging effects and prone to triboelectric effects.

[0026] Furthermore, the voltage level used may be of the order of 5 V, which is well below the generation of sparks or discharges. Thus, the device 1 is also suitable for use in environments with explosion hazards, such as in natural gas sources or coal mines.

[0027] The sensor 4 (eg, a probe holder) comprises a plurality of probes 5 which may be arranged in pairs. The probes 5 are arranged in contact with the material flow 20 and are connected to a programmable voltage source and a programmable voltage receiver.

[0028] The probe 5 (e.g., a pair of probes 5) can be designed to provide as small a capacitance gap as possible and as long a resistance measurement line as possible between the pair of probes 5 and within the material flow 20. According to some embodiments, the probe 5 can be made of metal. Common to all embodiments is that the probe 5 can be at least partially conductive. The metal can be selected to achieve a long life of the probe 5 in the material flow 20.

[0029] A large resistive sensitive line produces a large absolute change in conductivity in the imaginary part of the complex impedance. A small capacitive gap along a long line produces a large measurable capacitance. Therefore, the absolute change in capacitance is also large. This property is particularly well realized by curve forms such as meander structures, Sierpinski curves or Peano curves.

[0030] The device 1 is configured to measure the ratio between the received voltage waveform and the applied voltage waveform for a set of predetermined frequencies, and based on the measured ratio, determine a set of complex impedances between at least two probes 5 for each of the predetermined frequencies. The set of complex impedance values ​​is considered to be coordinates in a higher dimensional Euclidean vector space. For example, N predetermined frequencies cause N complex coordinates consisting of 2N coordinate values. Therefore, the measurement is described by a point in a 2N-dimensional vector space. Since the space is regarded as a Euclidean space (as a concept of distance), the average value remains valid. The device 1 is also configured to determine a set of time averages of the complex impedance determined for each of the predetermined frequencies using a time window, and determine a set of standard deviations based on the determined time averages. The device 1 is also configured to indicate that water is detected when at least one of the standard deviations exceeds a threshold condition. That is, the device 1 is configured to include an indication criterion, which will be used as a threshold condition if the distance of the local measurement point to the average value exceeds a predetermined geometric form.

[0031] According to some embodiments, each of the at least two probes 5 may include one or more heaters. There may be one heater per pair of probes 5. The heater may be adapted to be controlled externally, for example in an on-off manner, to stabilize the temperature to a predetermined value. The heater may be resistive. A typical resistive heater may be a commercially available heater element for a 24V soldering iron. A heating power of 200W to 500W may generally be sufficient. The heater serves two different purposes:

[0032] Once the sensor 4 detects water, the heater can be turned on. Once water is detected by a significant change in the properties found in the measured set of impedances, this change persists until the water dries up or is otherwise removed by the flow 20. During this time, no useful measurements can be made. This time is called the blind time. This time is typically in the range of seconds which does not substantially interfere with the drilling operation. However, it may be desirable to reduce the blind time or force a restart in dry conditions. This is done by activating the heater until the probe dries up.

[0033] The heater may also be switched on periodically to detect the presence of water in the conductive material stream 20 by using indirect heat capacity measurement. In the presence of water, the set of impedances measured will correlate with heater activity. If no water is present, no correlation is found between the set of impedances and heater status. Thus, the method is self-calibrating with respect to changes in the properties of the stone being drilled.

[0034] According to some embodiments, one of the at least two probes 5 may include one or more heaters, wherein the heater may be adapted to be controlled from the outside to stabilize the temperature to a set of predetermined values. One of the at least two probes 5 (which may be referred to as the ambient probe) is placed at ambient temperature (which may be assumed to be less than 100C), and one of the at least two probes 5 (which may be referred to as the heated probe) is heated to a temperature slightly greater than 100C. Due to convective cooling, the temperature of the heated probe is reduced by the material flow 20 and may need to be constantly stabilized. Complex impedance may be measured in both probes 5. The ambient probe may produce a potential signature of water contamination. A probe at a temperature greater than 100C will produce a dry signature in all cases. The ambient probe will produce a signature that is ultimately contaminated by water. As long as the material flow 20 does not contain any water, the two responses are equivalent within the reproducibility of the measurement results. Once the material flow 20 will contain water, there will be a difference. Recording this difference of a set of complex impedances detects the presence of water in a first manner. In the first manner, it can be directly represented without time integration or averaging.

[0035] However, under the influence of particularly large amounts of water, the real part of the grouped complex impedance may drop significantly on both the heated and ambient probes. As a result, both probes will exhibit blind times. However, the blind time on the heated probe will be significantly smaller than the blind time on the ambient probe. The difference in this return slope can be used as a way to detect the presence of water in a second manner.

[0036] Using this second approach, a heater can also be applied to the ambient probe to reduce the blind time of the sensor. Special care should be taken in this case, as the additional heater may create a situation where both probes 5 are hot and water will remain undetected. Since alpha errors (i.e. water not detected when it is present) should be avoided, it has proven more effective to accept a higher beta error (i.e. water detected when it is not present) instead. These indirect heat capacity measurements enable self-calibration over short time delays. Another advantage is that the temperature of the heated probe can be set, for example, to 125C instead of 360C in the on-off case.

[0037] According to some embodiments, each of the at least two probes 5 may include one or more heaters, wherein the heater is adapted to be controlled from the outside to monitor the heating current and / or temperature. That is, the ability to monitor the current through the heater and / or the temperature of the heater has been added. The presence of water can be indicated by the decrease in the real part of the group difference between the heated electrode and the unheated electrode pair (e.g., the paired probes 5). At the same time, when water suddenly appears, there may be a significant increase in the heater current. The water in the material flow 20 can evaporate, which makes it more efficient to cool the heated probe. There is no such effect in the environmental probe pair. In almost all cases, the peak value of the heating current and the decrease in the differential impedance are clear indications of water. These indirect heat capacity measurements can achieve low beta errors and self-calibration for short time delays. Another advantage is that the temperature of the heated probe can be set to 125C instead of 360C in the on-off case, for example.

[0038] According to some embodiments, the sensor 4 comprises at least three probes 5, wherein each of the three probes 5 comprises one or more heaters. The heaters are adapted to be controlled from the outside to monitor the heater current and measure the temperature. The probes 5 can be heated to a given temperature and to different temperatures. Using these embodiments, the temperature can be limited to below 100C. Then, the measurement can no longer be based on the required evaporation energy, but simply on the cooling effect: making the material flow 20 substantially and on average drier than the material accumulated on the probes 5, the material accumulated on the probes 5 being in evaporation equilibrium with the flow 20. Therefore, drying the probe will cool the probe, and the cooling of the probe is measured by measuring the temperature of the probe directly or by indirectly measuring the required heater energy required to keep the temperature at a predetermined level. Since the relationship between the required heaters is a function of the temperature, three temperature points are sufficient to establish the existence of evaporation equilibrium.

[0039] According to some embodiments, the heater may be resistive. As described above, the current and / or temperature through the resistive heater may be monitored. The presence of water is now indicated by a set of drops in the real part of the difference between any of the pairs of heated and unheated probes 5. At the same time, a significant increase in the heater current in the heated probes may occur. Since the heated probes are set to different temperatures, e.g. 40C, 60C, 80C, the required increase in heating current may be proportional to the difference in temperature of the material flow 20 from the set temperature. With three probes 5, a linear relationship between the required resistive heater currents may be calculated. During the resistance drop time, there are several features in the measured data that allow for almost perfect water detection, such as:

[0040] The measured drops have different lengths, since the time for drying depends on the set temperature.

[0041] The lowest heated probe will show the longest drop, while the hottest probe will show the shortest drop. Any other drops, for example caused by inhomogeneities of the material flow 20, will not have such a statistical connection and can therefore be excluded.

[0042] In the presence of a resistance drop, the heater currents of all three heaters may rise and substantially deviate from the previous linear relationship. These indirect heat capacity measurements enable more or less no beta errors and self-calibration for short time delays. Other advantages are that the temperature of the heated probe can be set, for example, to values ​​below 100C without evaporation and the cooling effect is sufficient.

[0043] According to some embodiments, an alarm may be activated when water is detected. Drilling may then be stopped automatically or manually by an operator.

[0044] According to some optional embodiments, since mucus (e.g., water-contaminated dust) may accumulate on the sensor 4, a power resistor (e.g., a resistive heater) may be arranged in thermal contact with the probe 5, allowing the probe 5 to be heated, e.g., to above 100° C. The heating may evaporate traces of water and accelerate the return of the probe 5 to an operational state.

[0045] According to some optional embodiments, since paste, water-contaminated dust may accumulate on the sensor 4, the ultrasonic oscillator can be arranged in mechanical contact with the probe 5, thereby allowing more efficient dust removal. When used herein, the ultrasonic oscillator is intended to prevent the accumulation of material and the solidification of material, thereby preventing the probe 5 from being shielded by the material flow 20.

[0046] In an embodiment, the device 1 includes a programmable voltage waveform source and a programmable voltage waveform receiver, such as a controllable AC voltage source amplifier, and the control unit 2 includes an analog-to-digital converter and an analog switch that allows comparison between a reference impedance and a measured impedance. These are configured to provide data on the complex impedance between the paired probes 5. At a given time, exactly one pair of probes 5 is active. The complex impedance data is read by the control unit 2 to calculate the necessary mean and standard deviation. The control unit 2 is configured to save data for recording and improvement purposes. The control unit 2 provides a communication channel on which the state of the system can be transmitted to the remote unit 6. The remote unit 6 has a receiver for said communication and provides a device indicating the state of the setting. Data can be sent in any known manner, such as by wire or wirelessly.

[0047] The embodiments herein provide a fast response for detecting water in the material stream 20. The response can be on the order of milliseconds. Another advantage of the embodiments herein is that the system performance can be programmed. Other advantages of the embodiments herein are that the electronics used are simple and consist of common commercially available multi-source components.

[0048] Figure 3 The flowchart in shows an example method of how the embodiments herein may be employed in terms of actions. Figure 3 An example method for detecting water in a material flow 20 during drilling is shown. Some optional example embodiments that can be used in the process will also be described. The apparatus 1 comprises a control unit 2, a data acquisition unit 3, a sensor 4 and a drilling rig 10. The sensor 4 comprises at least two probes 5, wherein the at least two probes 5 are arranged in contact with the material flow 20 and are connected to a programmable (e.g. tunable) voltage source and a coherent programmable (e.g. tunable) voltage receiver capable of measuring the complex resistance between the probes 5.

[0049] Action 301 comprises: for a set of predetermined frequencies, measuring the ratio between the received voltage and the applied voltage. This ratio will be used to calculate the complex impedance. The predetermined frequencies can be associated with wavelengths that are much larger than the distance between the probes 5. This is advantageous because radiation effects, interferences, are completely avoided. According to some embodiments, the predetermined frequencies can be in the interval of 0.1kHz to 30kHz. This interval is selected for legal reasons. In these cases, the detection system is not considered a generator of electromagnetic radiation. In addition, there are commercially available chipsets for impedance measurement in the frequency region.

[0050] Action 302: Impedance is thus measured using a programmable sinusoidal voltage source and coherent detection (e.g., using an applied voltage and a received voltage). Using coherent detection, the real part of the complex impedance of the sensor 4 including the probe 5 and the imaginary part of the complex impedance can be calculated. The real part of the complex impedance is the conductivity, and the imaginary part of the complex impedance is the inductance and capacitance. By tuning the measurement frequency within a predetermined interval, a spectrum of the complex impedance can be generated over the frequency. The spectrum is used to detect the presence of traces of water. Therefore, based on the ratio between the measured received voltage and the applied voltage, the complex impedance between at least two probes 5 is determined for each of the predetermined frequencies.

[0051] Action 303 includes using a time window to determine a set of time averages of the determined complex impedance. Therefore, without calculating any other material parameters such as dielectric function, a time window is used to determine (e.g., calculate) a suitable time average of the determined complex impedance. Suitable time average means that an average value is established on a scale of several seconds where the material flow 20 can be assumed to be constant. For example, measuring at about 20kHz to 30kHz can achieve 10,000 measurement points per second. Using, for example, 16 frequency steps, an impedance set of about 1,000 measurements per second can be obtained. Typically, 500 to 1,000 measurement sets are integrated to produce a stable average. The presence of water appears suddenly, and the transition between the last dry state and the wet state occurs within a few milliseconds, generating a deviation on 10 to 15 samples. Therefore, any average value spanning the integration on more than 10 to 15 samples is acceptable. Integration over too long a time may make the system sensitive to material changes in the material flow 20. This occurs at the second level. Converting to samples, it is usually unwise to integrate over more than 10,000 samples. The average is always calculated and updated.

[0052] The measurement parameter is the instantaneous deviation of the average of the last few measured impedance sets from the time average obtained by averaging over a longer span of previously measured impedance sets. Considering the calculation of the average as a low pass filtering process with a predetermined integration time, the difference between the two low pass filters can be used as the measurement parameter. The filters have different integration times. The integration time of the shorter, faster filter is determined by the noise of the measurement system and is typically integrated over 2 to 5 samples. The integration time of the longer, slower filter is determined by the following two requirements: the integration time should be longer than the time to report a typical impedance change caused by water (typically 10 to 15 samples), and the integration time should be shorter than the time for a typical material flow parameter change (typically 1000 to 10,000 samples).

[0053] Action 304 includes determining a set of standard deviations based on the determined time averages and the same time window. Standard deviations are constantly determined and updated. The deviation information is used to adjust the threshold conditions under which the averages from the previous action 303 are considered significant. In a typical setting, any instantaneous change exceeding 1.5 to 3 standard deviations is considered significant for water detection.

[0054] Action 305 includes indicating the detection of water when at least one of the standard deviations exceeds a threshold condition. A strong deviation towards a smaller absolute value of the impedance indicates the presence of traces of water. This effect is caused by the conductivity of the water in the material flow 20. Typically, all water that meets these conditions is contaminated with salt. There is a predetermined factor (typically 1.5 to 3.0) that is used to determine a threshold condition for the measurement parameter associated with the standard deviation obtained above. Once the measurement parameter exceeds this threshold towards a smaller impedance, the detection of water is indicated. An alarm can be activated when water is detected, and drilling can then be stopped automatically or manually by an operator.

[0055] By following the above method, water detection during drilling is indicated in an enhanced and more efficient manner. For the sake of clarity, it should be understood that these steps can be repeated many times. This is usually the case because the method is performed continuously during drilling.

[0056] According to some embodiments, each of the at least two probes 5 may include one or more heaters. The heaters may be resistive, and there may be one heater per pair of probes 5. The heaters may be adapted to be externally controlled, e.g. in an on-off manner, to stabilize the temperature to a predetermined value.

[0057] According to some embodiments, one of the at least two probes 5 may comprise one or more heaters, wherein the heater may be adapted to be externally controlled to stabilize the temperature to a set of predetermined values.

[0058] According to some embodiments, each of the at least two probes 5 may include one or more heaters, wherein the heaters are adapted to be controlled from the outside to monitor the heating current and / or temperature. That is, the ability to monitor the current through the heater and / or the temperature of the heater has been added.

[0059] According to some embodiments, the sensor 4 comprises at least three probes 5, wherein each of the three probes 5 comprises one or more heaters. The heaters are adapted to be controlled from the outside, to monitor the heater current and to measure the temperature.

[0060] The above-mentioned heaters may be resistive, and there may be one heater for each pair of probes 5 .

[0061] It should be understood that the foregoing description and the accompanying drawings represent non-limiting examples of the methods and devices taught herein. Therefore, the devices and techniques taught herein are not limited by the foregoing description and the accompanying drawings. Instead, the embodiments herein are limited only by the appended claims and their legal equivalents.

Claims

1. A device (1) for detecting water in a stream of granular material (20) during drilling, in, The device (1) comprises a control unit (2), a data acquisition unit (3) and a sensor (4), wherein the sensor comprises at least two probes (5), wherein the at least two probes (5) are arranged in contact with the particle flow (20) and connected to a programmable voltage source and a programmable voltage receiver, and wherein the device (1) is configured to: - measuring the ratio between the received voltage waveform and the applied voltage waveform for a set of predetermined frequencies; - determining, based on the measured ratio, for each of the predetermined frequencies, the complex impedance between the at least two probes (5); - using the time window to determine a set of time averages of the complex impedance determined for each of said predetermined frequencies; - determining a set of standard deviations based on the determined time averages; and - When at least one of the standard deviations exceeds a threshold condition, detection of water is indicated.

2. The device (1) according to claim 1, in, Each of the at least two probes (5) comprises one or more heaters, wherein the heaters are adapted to be externally controlled to stabilize the temperature to a predetermined value.

3. The device (1) according to claim 1, in, One of the at least two probes (5) comprises one or more heaters, wherein the heater is adapted to be externally controlled to stabilize the temperature to a predetermined value.

4. The device (1) according to claim 1, in, Each of the at least two probes (5) comprises one or more heaters, wherein the heater current and / or heater temperature is adapted to be controlled externally to monitor the current and / or temperature.

5. The device (1) according to claim 1, in, The sensor (4) comprises three probes (5), and wherein each of the three probes (5) comprises one or more heaters, wherein the resistance heater current and / or heater temperature are adapted to be externally controlled to monitor the current and / or temperature.

6. The device according to claim 1, in, The predetermined frequency is within an interval of 0.1 kHz to 30 kHz.

7. The device according to claim 1, in, The probe (5) is made of metal.

8. A drilling rig (10) comprising a device (1) according to any one of claims 1 to 7.

9. A method for detecting water in a particle stream (20) during drilling by using a device (1), wherein the device (1) comprises a control unit (2), a data acquisition unit (3) and a sensor (4), in, The sensor comprises at least two probes (5), wherein the at least two probes (5) are arranged in contact with the particle stream (20) and connected to a programmable voltage source and a programmable voltage receiver, the method comprising: - measuring the ratio between the received voltage waveform and the applied voltage waveform for a set of predetermined frequencies; - determining, based on the measured ratio, for each of said predetermined frequencies, the complex impedance between at least two probes (5); - using the time window to determine a set of time averages of the determined complex impedance; - determining a set of standard deviations based on the determined time averages; and - When at least one of the standard deviations exceeds a threshold condition, detection of water is indicated.

10. The method according to claim 9, in, Each of the at least two probes (5) comprises one or more heaters, wherein the heaters are externally controlled to stabilize the temperature to a predetermined value.

11. The method according to claim 9, in, One of the at least two probes (5) comprises one or more heaters, wherein the heater is externally controlled to stabilize the temperature to a predetermined value.

12. The method according to claim 9, in, Each of the at least two probes (5) comprises one or more heaters, wherein the heater current and / or heater temperature are controlled externally to monitor the current and / or temperature.

13. The method according to claim 9, in, The sensor (4) comprises three probes (5), and wherein each of the three probes (5) comprises one or more heaters, wherein the heater current and / or heater temperature are controlled externally to monitor the current and / or temperature.

14. The method according to claim 9, in, The predetermined frequency is within an interval of 0.1 kHz to 30 kHz.

15. The method according to claim 9, in, The probe (5) is made of metal.

16. The method of claim 9, performed in a drilling rig (10).

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