EP4111187A1 - Appareil et procédé de détermination capacitive d'une proportion d'une substance dans un matériau - Google Patents

Appareil et procédé de détermination capacitive d'une proportion d'une substance dans un matériau

Info

Publication number
EP4111187A1
EP4111187A1 EP20803096.5A EP20803096A EP4111187A1 EP 4111187 A1 EP4111187 A1 EP 4111187A1 EP 20803096 A EP20803096 A EP 20803096A EP 4111187 A1 EP4111187 A1 EP 4111187A1
Authority
EP
European Patent Office
Prior art keywords
substance
proportion
frequencies
resonant circuit
measured
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP20803096.5A
Other languages
German (de)
English (en)
Inventor
Stefan Krämer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hilti AG
Original Assignee
Hilti AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hilti AG filed Critical Hilti AG
Publication of EP4111187A1 publication Critical patent/EP4111187A1/fr
Pending legal-status Critical Current

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/22—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance
    • G01N27/221—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating capacitance by investigating the dielectric properties

Definitions

  • the present invention relates to a device and a method for the capacitive determination of a proportion of a substance in a material.
  • the device comprises an oscillating circuit with a coil and a plate capacitor, wherein the oscillating circuit can be excited to oscillate with different frequencies or inductances.
  • the frequency response or resonance frequencies of the oscillating circuit are recorded and evaluated with regard to characteristic features. Using the frequencies that can be assigned to these characteristic features, the proportion of a certain substance in the material to be measured can be determined.
  • the method for capacitive determination of a proportion of a substance in a material is based in particular on the fact that the dielectric properties of the substance are used in the method in order to determine the proportion of the substance in the material to be measured.
  • substance concentrations or proportions of a substance in a material to be examined can be determined using optical methods.
  • optical methods which are known from the prior art, in particular the optical properties of the substance, the proportion of which is to be determined, are used for the partial determination.
  • Many optical methods are based on the fact that the substance, the proportion of which is to be determined, is dissolved in a liquid and the resulting solution is illuminated. The optical response of the lighting is recorded and plotted in the form of spectra. The concentration of the substance can then be deduced from the spectra of the absorbed and / or reflected radiation.
  • optical measuring method is described, for example, in DE 41 22 925 A1.
  • the invention described there relates to an optical spectrometer with an illumination device coupled to at least one optical waveguide for illuminating a substance to be examined spectroscopically contained in a measuring sample room, the spectrometer comprising a monochromator device and a detector arrangement.
  • the disadvantage of optical methods, as described in DE 41 22 925 A1 is that for the concentration determination of optical components must be used.
  • the use of optical components often leads to high costs and a considerable sensitivity of the measurement setup obtained, so that the measurement setup cannot be used outside a protected laboratory atmosphere.
  • the use of optical methods and devices based on such optical methods is very limited, if not impossible, in reality and especially in places with high vibration, noise and / or pollution potential, such as on a construction site.
  • optical methods are associated with the disadvantage that a liquid is always required in order to dissolve the substance to be measured.
  • a - preferably clean - solution liquid may not always be available.
  • the liquid is particularly necessary to examine the transitions or changes in the refractive indices between the optical measuring system and the sample. Due to the requirement of a solution liquid, it is not possible, for example, to determine the proportions of substances in non-liquid-soluble substances or in air using optical methods.
  • the object on which the present invention is based is thus to overcome the disadvantages and deficiencies of the prior art described above and to provide a device and a method for capacitive determination of a proportion of a substance in a materi al.
  • Experts would welcome it if the improved method and the improved device could also be used to determine substance proportions in non-water-soluble materials and if measurements were also possible in air.
  • the device to be provided should also be used in rough places, such as construction sites or the like, where shocks and heavy soiling are generally to be expected.
  • a robust, stable and insensitive device is to be provided to whoever. Another concern is that the method to be provided is inexpensive and user-friendly.
  • a device for the capacitive determination of a proportion of a substance in a material comprising an oscillating circuit with a coil and a plate capacitor.
  • the device is characterized in that the plate tenkondensator can be filled with the material as a dielectric, a frequency response of the dielectric being recorded and evaluated in order to determine the proportion of the substance in the material.
  • the invention in a second aspect, relates to a method for the capacitive determination of a proportion of a substance in a material.
  • the method is characterized by the following method steps: a) Provision of a proposed device, b) Filling a plate capacitor of the device with the material, the proportion of a substance in the material to be determined, c) Setting different frequencies or inductances in a resonant circuit of the Device, d) Detection of a frequency response or resonance frequencies of the material, e) Evaluation of the frequency response or the resonance frequencies by searching for characteristic features, f) Determination of the proportion of the substance using characteristic frequencies fc that can be assigned to the characteristic features.
  • quartz content in a dust to be measured is important information because quartz is associated with diseases such as silicosis or lung cancer. Since efforts are increasing in many countries to protect workers in mining or on construction sites better than before from high dust pollution and the associated negative health consequences, there is great interest in practicable, realistic and cost-effective technical solutions for the investigation of dust. Experts would particularly welcome it if a possibility could be created to be able to quickly and reliably determine a quartz content in a dust to be measured in order to be able to take suitable protective measures for the workers concerned.
  • the proposed device can be used as a “dust dosimeter” that can be carried by the workers on a construction site and that determines the amount of quartz to which the construction worker is exposed during the course of the day. Analogously to a steel dosimeter, the proposed device can record and save the recorded data or transmit them to another device for further processing. In the sense of the invention, it can also be preferred that the proposed device emits optical and / or acoustic warning signals that indicate to the worker, for example, that a maximum Daily exposure to quartz has been reached or will be reached in the near future.
  • the device is arranged on a vacuum cleaner or an air cleaner, so that the quartz content in the dust can be determined in the vicinity of the vacuum cleaner or the air cleaner.
  • the device is used in the vicinity or on a dust-generating device, such as a machine tool, in order to examine its composition directly at the point of origin of the dust and, in particular, to determine the quartz content.
  • the invention provides an inexpensive and insensitive technical solution for determining a substance content in a material to be measured, preferably dust here. This is achieved in particular in that the method and the use of the device for determining a substance proportion are capacitive and that the dielectric properties of the substance, the proportion of which is to be determined, are used to determine the proportion of the substance in the dust to determine. In the context of the invention, it is particularly preferred that the determination of the proportion of the substance in the dust takes place capacitively.
  • the dielectricity or the dielectric constant of the material to be measured is measured at different frequencies in order to determine the quartz content in a dust sample.
  • a frequency spectrum in particular is measured in order to obtain and evaluate a dielectric response from the dust sample.
  • the electromagnetic resonant circuit of the device is acted upon with a short pulse or a falling edge.
  • the capacitor For the purposes of the invention, it is preferred to charge the capacitor with a short pulse of known energy or voltage. After the capacitor has been charged, the energy or voltage is abruptly removed, this being possible, for example, by means of a short circuit across the coil of the electromagnetic resonant circuit.
  • the excitation of the resonant circuit can be carried out analogously.
  • the harmonic components of the excitation are selected or set at such a high frequency that they are set up to excite the quartz resonance.
  • the resonant circuit begins to oscillate at its resonant frequency.
  • the resonance frequency can preferably be detected with the control unit of the device.
  • the frequency can also be adjusted with the help of diodes, capacitance diodes and / or potentiometers until the frequencies relevant for quartz are reached.
  • the dielectricity or the dielectric constant of the material to be measured can be determined from the values set for the inductance L.
  • the quartz content in dust correlates with a change in the dielectricity or the dielectric constant of the dust in the range of the resonance frequency. In other words, the relation applies that “the greater the change in the dielectricity or the dielectric constant at the resonance frequency, the more quartz is contained in the dust”.
  • Another advantage that is achieved with the invention is that materials that are not soluble in water or liquid can also be measured.
  • the proposed method and the proposed device enable the determination of a substance content in air.
  • the advantages achieved with the invention are therefore in particular that capacitive measurements can be carried out with mechanically insensitive components and that no liquid solution medium is required for carrying out the measurements.
  • a device which comprises an oscillating circuit with a coil and a plate capacitor. It is preferred within the meaning of the invention that the device is set up to carry out the proposed method.
  • the coil can preferably be a wire coil, the properties of which are preferably described by the inductance L. It is preferred within the meaning of the invention that the coil to be used and its properties are selected depending on the substance to be detected or the material to be measured, as well as depending on the properties of the plate capacitor with which the coil is Forms resonant circuit of the proposed device. For example, a value of around 100 pH can be selected as the starting point for operating the resonant circuit. The person skilled in the art knows that this value can vary by several orders of magnitude, in particular with the size of the device.
  • the plate capacitor comprises two plates, between which a voltage can be applied.
  • Two alternative approaches can be used to carry out the proposed method.
  • the resonant circuit of the device can be equipped with a sinusoidal excitation signal. nal (“sine sweep”), a constant voltage amplitude preferably being used.
  • the voltage drop across the capacitor is recorded as if the electromagnetic resonant circuit were a voltage divider.
  • the voltage is recorded as a measured variable over a predetermined frequency, which can result in a voltage-frequency diagram. 2 shows such a diagram as an example.
  • This first method can be described with the following method steps: a) providing a proposed device, b) filling a plate capacitor of the device with the material, the proportion of a substance in the material being determined, c) setting different frequencies in an oscillating circuit of the device d) Detection of a frequency response of the material, e) Evaluation of the frequency response by searching for characteristic features, f) Determination of the proportion of the substance using characteristic frequencies fc that can be assigned to the characteristic features.
  • an electromagnetic resonant circuit in which inductances L of different sizes can be set or “ground in”.
  • the different inductances L represent the predetermined size in this second method.
  • the electromagnetic resonant circuit is then excited to oscillate, the resonance frequency being detected as a measured variable and / or plotted against the inductance. Frequency-inductance diagrams can thereby be obtained.
  • the electromagnetic resonant circuit is designed such that, when a first inductance is set, it vibrates at a first resonance frequency of quartz. This design is achieved in particular by setting a certain measuring inductance as a given size.
  • the measurement can then be repeated for different inductances that can be ground in the resonant circuit, the resonant circuit preferably oscillating in a second or further resonance of quartz during this second or every further measurement.
  • This second method can be described with the following method steps: a) providing a proposed device, b) filling a plate capacitor of the device with the material, in which Material the proportion of a substance is to be determined, c) setting different inductances in a resonant circuit of the device, d) recording the resonance frequencies of the material, e) evaluating the resonance frequencies by searching for characteristic features, f) determining the proportion of the substance using of characteristic frequencies fc which can be assigned to the characteristic features.
  • a voltage amplitude is regarded as “sufficiently large” in the context of the invention if it is set up to stimulate a resonance in the resonant circuit.
  • the plates of the plate capacitor are preferably aligned essentially parallel to one another. It is preferred in the context of the invention that the plate capacitor comprises connections for a voltage source and / or for a control unit.
  • the parameters of the plate capacitor or its plates can preferably be selected as a function of the substance to be detected or as a function of the material to be measured. These parameters are, for example, the size of the plates of the plate capacitor or their to each other.
  • the geometric parameters of the plate capacitor define a volume into which the dust to be measured can be filled as a dielectric.
  • the material in which the measurement takes place and which is introduced into the measurement volume between the plates of the plate capacitor is preferably referred to as the “material to be measured”.
  • the material to be measured is dust. This dust can occur, for example, on a construction site, especially when a substrate such as a wall, a wall, concrete, limestone or the like is processed with a machine tool such as a core drill, a saw, an angle or cut-off grinder or a hammer drill without being limited to these applications.
  • quartz can be contained in concrete or masonry, so that dust containing quartz can arise when processing such substrates.
  • the inventor has recognized that the density of concrete and quartz is approximately similar or comparable, so that this fact can be used for the capacitive determination of the quartz content in a dust sample.
  • the substance, the proportion of which is to be determined in the material to be measured is referred to as “substance, the proportion of which is to be determined”.
  • the substance whose part is to be determined is quartz. Quartz has the chemical composition SiO2 and is in particular in a crystalline lattice structure. Due to its structure, quartz can be polarized, whereby the polarization of a substance enables an unambiguous identification of a substance if its dielectric constant is measured and evaluated at characteristic frequencies.
  • the inventor has recognized that the dielectric properties of substances, in particular quartz, can be used to determine the proportion of the substance in a material to be measured, such as dust.
  • the dust as the material to be measured is introduced as a dielectric between the plates of the plate capacitor.
  • the properties of the plate capacitor can preferably be described with the capacitance C of the electromagnetic resonant circuit, which is part of the proposed device.
  • the device comprises a voltage source which is set up to excite the resonant circuit to oscillate.
  • the oscillations of the resonant circuit can be implemented by a voltage source, the voltage to be provided by the voltage source preferably being applied to the inductance L of the coil, the capacitance C of the capacitor, as well as the material properties of the material to be measured, as well as the material, its proportion is to be coordinated.
  • the voltage to be provided with the voltage source is selected as a function of the variables just mentioned.
  • the material properties of the material to be measured, as well as the material whose proportion is to be determined, can be, for example, their density, dielectric constant or the like. In the context of the invention, it is particularly preferred that the determination of the proportion of the substance in the dust takes place capacitively.
  • the frequencies with which the dielectric or the plate capacitor is applied ie measured, in a range from 0 to 1000 kHz, preferably in a range from 10 to 800 kHz and most preferably in range from 100 to 500 kHz. These frequency ranges are particularly advantageous and suitable for determining a proportion of quartz in the dust, since characteristic features in the frequency response for quartz in a certain test setup are, for example, around 150 and 250 kHz.
  • the specified values can depend on the size, the geometry and / or the water content of the material to be measured, which is why it is preferred in the context of the invention that calibration measurements are carried out with the measurement setup to be used, for example to determine the position of the to determine characteristic frequencies.
  • the frequencies are resonance frequencies of the oscillating circuit that are passed through by a different action on the oscillating circuit or its components.
  • the resonance frequencies of the electromagnetic oscillating circuit can be detected or measured by a control unit, which is explained further below, wherein the control unit can be part of the proposed device.
  • the control unit can preferably be designed as a microcontroller.
  • a quality of the electromagnetic resonant circuit is measured by the control unit. For this purpose, a voltage drop across the coil and the capacitor as well as a phase angle are measured and evaluated by the microcontroller.
  • the quality of the electromagnetic resonant circuit can be used as a correction variable in order to exclude measurement errors that can occur when the resonance frequencies of different substances whose proportions are to be determined in a material are very similar or in a similar range.
  • the quality of the electromagnetic resonant circuit can preferably be used to distinguish the resonances or frequencies of the first and second substances from one another.
  • the electromagnetic resonant circuit of the proposed device is excited to oscillate at different frequencies, with a frequency response of the dielectric, ie of the dust to be measured, being subsequently recorded and evaluated in order to determine the proportion of the substance, its proportion should be determined to determine in the dust.
  • these steps are preferably also referred to as “setting different frequencies in an oscillating circuit of the device” and as “recording a frequency response of the dust”.
  • the device comprises a control unit which is set up to detect the frequency response of the dielectric.
  • the control unit of the device is preferably designed as a microcontroller.
  • the control unit is preferably a preferably freely programmable processor which can have integrated peripheral functions.
  • the control unit is set up in particular to control the sensors and / or detection devices of the proposed device. It can also be set up to store and / or evaluate the measured values acquired with the sensors and / or acquisition devices.
  • the frequency response of the dust to be measured is recorded and evaluated with the microcontroller.
  • the voltage between the plates of the plate capacitor is measured and plotted against the different frequencies, as a result of which a frequency-voltage diagram is obtained (see FIG. 2).
  • control unit is also set up to apply different frequencies to the dielectric. This can be achieved, for example, in that the control unit is able to switch a voltage on or off.
  • the electromagnetic resonant circuit is excited by a voltage source. Most preferred in the context of the invention is the use of a voltage source controlled by the control unit in order to excite the electromagnetic resonant circuit or to apply different frequencies to the dielectric.
  • the microcontroller can also be used to hit the electromagnetic resonant circuit of the proposed device with different frequencies, the reaction of the dielectric to the passing through of the different frequencies in the context of the present invention being detected and evaluated in order to determine the proportion of a To determine the substance in dust.
  • the response of the material to be measured is recorded in the form of a voltage.
  • the frequency response of the dielectric, ie of the material to be measured can be plotted in a frequency-voltage diagram.
  • the frequencies with which the oscillating circuit is acted upon or with which the oscillating circuit is excited are shown on the x-axis of the slide. while the frequency response of the dust is plotted on the y-axis of the diagram.
  • the frequency response of the material to be measured can then be evaluated by searching for characteristic features in the plot.
  • the frequency-voltage diagram can be examined for characteristic features of the curve.
  • a frequency-inductance diagram can preferably be evaluated.
  • characteristic peaks can be searched for in the frequency-voltage diagram, the peaks being defined in particular by characteristic frequencies fc for a specific material.
  • this preferably means that different substances in the material to be measured can be recognized by the location of characteristic features in the frequency-voltage diagram.
  • Such peaks for quartz are, for example, at frequencies of approx. 150 and 250 kHz.
  • the presence of quartz in a dust sample to be measured can be inferred if peaks or abnormalities at frequencies of approx. 150 and 250 kHZ occur.
  • the characteristic frequencies fc in the case of crystalline materials often result from the lattice structure of the material. In a preferred exemplary embodiment of the invention, this leads to the desired determination of a proportion of quartz in a dust sample to the characteristic frequencies fc1 «150 kHz and fc2» 250 kHz.
  • the device comprises a relay, an analog switch and / or a gyrator circuit for setting different frequencies in the resonant circuit.
  • the inductance of the coil of the resonant circuit can preferably be changed, a change in the inductance of the coil advantageously leading to a change in the frequencies of the resonant circuit.
  • the different inductivities can be set, for example, by electrically looping in the coil of the resonant circuit.
  • it is preferred that smaller changes in the frequencies are achieved by setting capacitances of different sizes, the capacitance describing, for example, properties of capacitance diodes that can be connected in series or in parallel with the plate capacitor of the resonant circuit.
  • the device comprises capacitance diodes for setting different frequencies in the resonant circuit, the capacitance diodes being connectable in series or in parallel with the plate capacitor of the resonant circuit. It is therefore preferred in the context of the invention that the capacitance of the capacitance diodes can be used to set different frequencies in the resonant circuit. Depending on the sign of the frequency change sought within the resonant circuit, the capacitance diodes can be connected in series or in parallel with the plate capacitor of the resonant circuit. It is preferred in the context of the invention that the capacitance diodes represent electrically controlled capacitances, their control preferably taking place by means of the control unit.
  • variable inductances of the coil and capacitances of the diodes are set by the control unit. This process is preferably also referred to as grinding in.
  • the (resonance) frequency of the electromagnetic oscillating circuit of the proposed device changes and the material to be measured is subjected to different frequencies.
  • the desired proportion of material can be determined using the electrical parameters of the electromagnetic resonant circuit.
  • the dielectric constant or the dielectric constant of the material to be measured is proportional to a good approximation to a quartz content in the material or dust volume of the capacitor. If, for example, a dielectric constant of 1 is measured when measuring with quartz-free dust and when measuring with a material with a high quartz content, the quartz content of which is approximately 100%, a dielectric constant of 5 can be measured when measuring dust with an unknown quartz content With a measured dielectric constant of 3, it can be concluded that the quartz content in this dust sample is in a range of approx. 50%. This assignment is also based on the knowledge that quartz and concrete have similar densities.
  • This determined quartz fraction can advantageously be related to the air volume from which the dust sample was extracted or filtered out in order to determine the quartz content of the breathing air, for example of a worker on a construction site.
  • changes in the frequencies are brought about by setting different inductances, the inductance describing properties of a coil of the resonant circuit of the device.
  • a relay for example, can be used to set different inductivities.
  • changes in the frequencies are brought about by setting different capacities, the capacitance describing properties of capacitance diodes that can be connected in series or in parallel with the plate capacitor of the resonant circuit.
  • the invention relates to a sensor device for determining a proportion of a substance in dust, the sensor device having a plate capacitor which can be filled with dust as a dielectric, a frequency response of the dielectric or a shift in a frequency spectrum being measured and evaluated is used to determine the proportion of the substance in the dust.
  • the substance whose proportion in the dust is to be determined is quartz. There is great interest in information about the proportion of quartz in dust samples, since the quartz has properties that are hazardous to health.
  • the capacitor is not necessarily filled with the material to be measured, but that the capacitor measures into the material to be measured from one side.
  • the material to be measured can be present in spatial proximity to the plate capacitor, wherein the material to be measured can cause a change in measured variables that can be recorded with the capacitor. With this capacitive measurement method, these changes can be detected and evaluated.
  • an electromagnetic resonant circuit with variable frequency is used for the measurement, the resonance frequency, quality and voltage drop of the electromagnetic resonant circuit being measured via the coil and the capacitor.
  • the resonance frequency of the electromagnetic oscillating circuit can be adjusted using different inductances and capacitances.
  • a plate capacitor is used to carry out the proposed method for determining a substance content by introducing the material to be measured, here a dust sample, between the plates of the plate capacitor.
  • a second electromagnetic resonant circuit can be used, the waveform of which can be superimposed with the waveform of the plate capacitor previously used to improve the measurement.
  • the device comprises a second resonant circuit, the measured values of which can be superimposed with the measured values of the first resonant circuit in order to further improve the accuracy and reliability of the determination method and the device.
  • a second electromagnetic resonant circuit takes into account the knowledge that an “ideal” frequency of the resonant circuit can deviate from frequencies that actually occur. This can be due to air humidity or thermal expansion of the plate capacitor, for example, without this list being exhaustive. It is therefore possible to use a second electromagnetic resonant circuit into which no dust is filled.
  • the voltage values of the two oscillating circuits add up to a maximum of twice the value of the voltage of one of the two oscillating circuits or the voltages cancel each other out so that a total voltage of 0 V is obtained.
  • the first electromagnetic oscillating circuit is filled with the material to be measured, its oscillation frequency preferably changes.
  • the frequency of the beat of the two resonant circuits is advantageously proportional to the quartz content of the material that was filled into the plate capacitor of the first resonant circuit. It is an essential advantage of this embodiment of the invention that any influences of air humidity or temperature remain outside the evaluation of the interference values or the beat of the two oscillating circuits and do not falsify the thus determined quartz content.
  • Fig. 2 Plot of the detected voltage versus different frequencies that can be set in the resonant circuit to determine the desired proportion of substance NEN.
  • FIG. 1 shows a schematic representation of a preferred embodiment of the device 1.
  • the device 1 comprises an electromagnetic resonant circuit 2, which in turn comprises a coil L and a capacitor C.
  • the capacitor C is designed as a plate capacitor. It preferably has two plates between which there is an electric field.
  • a material such as dust can be filled into the volume that is formed between the plates of the plate capacitor. It is preferred within the meaning of the invention that this material is to be examined for its constituent substances, as well as their proportions in the material.
  • the resonant circuit 2 can be acted upon with different frequencies.
  • the corresponding vibrations are excited by a voltage source 3.
  • the voltage source 3 can preferably be designed as a frequency generator or sine wave generator. In the context of the invention, it can also be preferred that the control unit 4 and the voltage source 3 form a unit.
  • the device 1 can comprise a control unit 4, which is preferably designed as a microcontroller. It is preferred in the context of the invention that the control unit 4 is set up to detect the frequencies in the resonant circuit 2 and its quality. Furthermore, the control unit 4 can be set up to electrically adjust or “loop in” the capacitances and inductances of the resonant circuit 2. It is preferred in the context of the invention that the control unit 4 comprises a device for voltage measurement, which can be designed, for example, as an oscilloscope with an integrated option for performing a fast Fourier transformation. It is particularly preferred in the context of the invention that the control unit 4 is provided in particular to carry out frequency measurements.
  • the oscilloscope is preferably set up to detect an amplitude of the frequency falling across the capacitor C.
  • the amplitude of the frequency falling across the capacitor C represents the measured variable in the proposed method.
  • This preferably means the excitation of the electromagnetic resonant circuit 2 with a preferably sinusoidal excitation signal which can be generated by a frequency generator.
  • the peak values of the voltage of the empty capacitor C are then compared with the peak values of the capacitor C filled with dust containing quartz.
  • the resonance frequencies can be determined by the position of the peaks in the frequency-inductance diagrams or the voltage-frequency diagrams.
  • Fig. 2 shows a plot of the detected voltage versus different frequencies that can be set in the resonant circuit 2 to determine the desired proportion of substance.
  • the upper part a) of FIG. 2 shows a voltage-frequency diagram for a quartz-free dust
  • the lower part b) of FIG. 2 shows a voltage-frequency diagram for a quartz-containing dust.
  • the material to be measured in the upper part a) of FIG. 2 is quartz-free dust
  • the material to be measured in the lower part b) of FIG. 2 is quartz-containing dust.
  • the frequency or the resonance frequency f of the resonant circuit is plotted in the unit kilohertz (kHz), while the voltage detected by the control unit 4 is plotted on the y-axis of the voltage-frequency diagram U is written in units of volts (V).
  • the diagram shown in FIG. 2 allows the frequency response to be evaluated by searching for characteristic features, as proposed according to the first evaluation method using voltage-frequency diagrams.
  • the proportion of the substance is determined in particular using characteristic frequencies fc that can be assigned to the characteristic features.
  • the lower part b) of FIG. 2 clearly shows the characteristic frequencies fc1 and fc2, which are at frequencies of approximately 150 kHz and 250 kHz.
  • the position of these characteristic frequencies fc1 and fc2 suggests that quartz is present in the examined dust, which is present in the plate capacitor C of the device 1.
  • quartz is the substance whose proportion in the material to be measured, here dust, is to be determined.

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Abstract

L'invention se rapporte à un dispositif et à un procédé de détermination capacitive d'une proportion d'une substance dans un matériau. L'appareil comprend un circuit oscillant doté d'une bobine et d'un condensateur à plaques, le circuit oscillant pouvant être excité afin d'osciller à différentes fréquences ou inductances. Selon l'invention, la réponse en fréquence ou les fréquences de résonance du circuit oscillant sont détectées et analysées par rapport à des éléments caractéristiques. En fonction de fréquences pouvant être attribuées auxdits éléments caractéristiques, la proportion d'une substance spécifique dans le matériau à mesurer peut être déterminée. Le procédé de détermination capacitive d'une proportion d'une substance dans un matériau est fondé en particulier sur le procédé utilisant les propriétés diélectriques de la substance afin de déterminer la proportion de la substance dans le matériau à mesurer. Une proportion de quartz dans un échantillon de poussière est de préférence déterminée. La proportion de quartz dans une poussière à mesurer représente une information importante car le quartz est associé à des maladies telles que la silicose ou le cancer du poumon.
EP20803096.5A 2020-02-25 2020-10-15 Appareil et procédé de détermination capacitive d'une proportion d'une substance dans un matériau Pending EP4111187A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020001370.8A DE102020001370A1 (de) 2020-02-25 2020-02-25 Verfahren und Vorrichtung zur kapazitiven Messung von Stoffkonzentrationen
PCT/EP2020/079039 WO2021170258A1 (fr) 2020-02-25 2020-10-15 Appareil et procédé de détermination capacitive d'une proportion d'une substance dans un matériau

Publications (1)

Publication Number Publication Date
EP4111187A1 true EP4111187A1 (fr) 2023-01-04

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EP20803096.5A Pending EP4111187A1 (fr) 2020-02-25 2020-10-15 Appareil et procédé de détermination capacitive d'une proportion d'une substance dans un matériau

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US (1) US20230117051A1 (fr)
EP (1) EP4111187A1 (fr)
CN (1) CN114930163A (fr)
DE (1) DE102020001370A1 (fr)
WO (1) WO2021170258A1 (fr)

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US8102181B2 (en) * 2008-04-21 2012-01-24 Enerize Corporation Method and device for rapid non-destructive quality control of powdered materials
US8309024B2 (en) * 2008-04-23 2012-11-13 Enerize Corporation Methods and systems for non-destructive determination of fluorination of carbon powders
CH699753A1 (de) * 2008-10-16 2010-04-30 Uster Technologies Ag Vorrichtung und verfahren zum ausmessen einer kapazität.
EP2634568A1 (fr) * 2012-03-02 2013-09-04 parelectrics UG (haftungsbeschränkt) Mesure non invasive des propriétés diélectriques d'une substance
US20170336337A1 (en) * 2016-05-18 2017-11-23 Tty-Säätiö Method and apparatus for monitoring a heterogeneous mixture

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WO2021170258A1 (fr) 2021-09-02
DE102020001370A1 (de) 2021-08-26
CN114930163A (zh) 2022-08-19
US20230117051A1 (en) 2023-04-20

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