[go: up one dir, main page]

WO1997004305A1 - Procede et appareil permettant de determiner la composition d'une matiere et de detecter la presence de polluants dans le sol - Google Patents

Procede et appareil permettant de determiner la composition d'une matiere et de detecter la presence de polluants dans le sol Download PDF

Info

Publication number
WO1997004305A1
WO1997004305A1 PCT/NL1996/000276 NL9600276W WO9704305A1 WO 1997004305 A1 WO1997004305 A1 WO 1997004305A1 NL 9600276 W NL9600276 W NL 9600276W WO 9704305 A1 WO9704305 A1 WO 9704305A1
Authority
WO
WIPO (PCT)
Prior art keywords
determining
soil
indicator
conductivity
capacitance
Prior art date
Application number
PCT/NL1996/000276
Other languages
English (en)
Inventor
Maximus Andreas Hilhorst
Original Assignee
Instituut Voor Milieu- En Agritechniek (Imag-Dlo)
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 Instituut Voor Milieu- En Agritechniek (Imag-Dlo) filed Critical Instituut Voor Milieu- En Agritechniek (Imag-Dlo)
Priority to AU63200/96A priority Critical patent/AU6320096A/en
Publication of WO1997004305A1 publication Critical patent/WO1997004305A1/fr

Links

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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials

Definitions

  • Method and apparatus for determining a material composition such as the presence of pollutants in a soil.
  • the invention relates to a method for determining a material composition and to an apparatus for implementing this method. It i ⁇ known from WO 86/052778 that contaminants in the soil can be detected by determining the dielectric properties thereof. By means of positioning a probe in the soil and determining the dielectric dispersion, i.e. the difference in dielectric constant at different frequencies, the soil can be tested in situ. In particular it is possible to assess the soil condition, the water content and the presence of oil products in the soil by determining the behaviour of the dielectric constant at different frequencies and comparing the measured values with a number of calibration curves. Such an apparatus has the drawback that an accurate determination of the pollutants requires a comparison of the measured values with a relatively large number of calibration curves. Thi ⁇ is relatively laborious, since a prior calibration measurement is required or a large number of reference curves for different type ⁇ of soil has to be stored.
  • the method according to the invention comprises the ⁇ teps of: a. measuring the impedance of a material at at least two different positions, such as depths x and x + ⁇ x, or at at least two times x and x + ⁇ x b.
  • the indicator i ⁇ preferably formed by: a + dG ⁇ x ) ⁇ wherein a jb+dC(x) and b are sensitivity parameters which can be chosen freely.
  • the indicator can be employed for determining stratifications in a material, such as, for example, a solid or liquid substance stored in a silo or container.
  • the indicator can be used to establish variation in density, differences in material composition, the presence of
  • the indicator employed for determining pollutants in a soil.
  • pollutants refers to a substance or soil structure which deviates from the natural soil composition and/or structure.
  • the dielectric properties of a material are a function of the composition.
  • the real part of the permittivity, e' can be determined by mea ⁇ uring the capacitance, C, between two electrode ⁇ with the ⁇ oil material in between a ⁇ the dielectric.
  • the imaginary part, e" can be found by determining the conductivity, G, between the ⁇ ame electrode ⁇ .
  • Both the capacitance and the conductivity are a function of the water content.
  • the real part of the permittivity is a function of the dipole moment, colloidal polarization, water content, binding of water etc.
  • the imaginary part is a (different) function of the water content, dielectric losses, but also, for example, of ionic mobility, the type of ions, the viscosity, surface effects of the particles of the material etc.
  • the following procedure can provide an indication of changes in the composition of the material, in particular changes in the compositio of soil strata which may or may not contain pollutants such as contaminants.
  • the procedure provides information which can be used to detect contamination.
  • location x for example a depth position
  • the capacitance and conductivity are measured of a capacitor with the material in between, as is done at location x + ⁇ x.
  • the ratio of the derivatives, with respect to x, of the conductivity and the capacitance now is a function of the change in the composition of the material.
  • This pollution indicator can be expressed in a formula in the following manner:
  • Indicator 4---. . dG( ,x) v , , in which a and b are constants or functions, by means of which the sensitivity of the indicator can be adjusted.
  • dC(x) the same analogously applies to dC(x).
  • the above ratio is mainly determined by the natural composition of the soil, and that this ratio does not vary greatly for a relatively small distance ⁇ x in, for example, depth of uncontaminated soil (for example over a distance ⁇ x of 1 cm).
  • hydrophobic contaminants form small droplets in the soil o may form an extended layer above impermeable soil strata.
  • Substances which are lighter than water form a layer above the water table, a so ⁇ called floating layer.
  • Substances which are heavier than water form a so- called sinkage layer on impermeable soil strata.
  • Sub ⁇ tance ⁇ which are hydrophilic mix with the ground water.
  • Figure 1 shows a graphic representation of the contamination indicator for a non-contaminated soil
  • Figure 2 shows the contamination indicator for a contaminated soil
  • Figure 3 shows a circuit for determining the contamination indicator
  • Figure 4 shows a partial cros ⁇ -section of the frontmost portion of a soil probe according to the invention.
  • the value ⁇ a and b can be cho ⁇ en in such a way that a particular substance is clearly indicated by the indicator. It can be clearly seen from Figure 2 that the contamination can be detected at various depths.
  • a contamination also give ⁇ ri ⁇ e to change ⁇ in the dielectric frequency ⁇ pectrum.
  • the "indicator” being determined for a plurality of frequencies, this can be used to gain even more insight into the contamination.
  • Figure 3 ⁇ chematically ⁇ how ⁇ the mea ⁇ uring set-up for determining C(x) and G(x) from the measured impedance of the soil.
  • the electrode configuration having in between, as the dielectric, the soil to be inspected for contamination is represented as a complex impedor Z*.
  • Via a supply lead 1 an alternating current is fed, via a switch 3, to an input terminal 5 of the impedor Z*.
  • the a.c. source 7 is formed by a crystal oscillator which generate ⁇ a ⁇ inu ⁇ oidal current with an adju ⁇ table o ⁇ cillator frequency between 1 MHz and 100 MHz.
  • Via a shunt line 9 the output signal of the oscillator 7 is fed to a switch 11.
  • the switch 11 can be connected, selectively, to a phase- ⁇ hifting element ⁇ uch a ⁇ a capacitor 13 or a con ⁇ tant-pha ⁇ e element ⁇ uch a ⁇ a re ⁇ i ⁇ tor 15.
  • the input terminal 5 of the electrode configuration and the input terminal of the capacitor 13 or the re ⁇ i ⁇ tor 15 are connected to a multiplier 17, the voltage ⁇ formed over the electrode configuration Z* and the element 13 or 15, u z and u s ft , respectively, being multiplied by one another.
  • the product u -u hift is fed to a low-pass filter 19.
  • the signal of the output of the low-pass filter 19 is converted in an analog-digital converter 21 who ⁇ e output is connected to the input of an arithmetic unit 23.
  • the capacitance C(x) and conductivity G(x) determined at different positions x are used to determine the ratio a+ dG(x) Vi dC(x) a control unit 25 the switches 3, 11, the analog-digital converter 21 and the arithmetic unit 23 are driven so as to perform one or more measurements at one or more position ⁇ .
  • the measurement of the impedance Z* of the electrode configuration is based on synchronous detection.
  • the sinusoidal voltage having a frequency ⁇ which can be selected between 1 MHz and 100 MHz is fed to the multiplier 17.
  • the phase of the current which is fed to the multiplier 17 via the shunt line 9 can be pha ⁇ e- ⁇ hifted by 0° or 90° by po ⁇ itioning the switch 11.
  • the voltage u z which is generated on the input terminal of the phase- ⁇ hifting element 13 or the constant-phase element 15 i ⁇ fed to the other input terminal of the multiplier 17.
  • the low-pass filter 19 removes the a.c.
  • the circuit in Figure 3 is constructed as an integrated circuit in the form of an ASIC.
  • Figure 4 ⁇ how ⁇ a ⁇ oil probe 25 provided with a fir ⁇ t annular electrode 26 and a second annular electrode 27.
  • the electrodes 26 and 27 are separated from one another, in the axial direction, by an insulating material 28 such a ⁇ , for example, a wear-re ⁇ istant ceramic material.
  • the electrodes 26 and 27 are situated near the pointed end of the probe 25.
  • Each electrode 26, 27 is connected to a circuit 29 of the type as shown in Figure 3.
  • the circuit 29 is preferably incorporated in the end of the probe 25, near the electrodes 26 and 27.
  • the length of the electrodes is preferably 1 centimetre, and a cros ⁇ -section thereof is approximately 3 centimetres.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analyzing Materials By The Use Of Electric Means (AREA)

Abstract

Cette invention concerne un procédé et un appareil permettant de déterminer la composition d'une matière et de détecter la présence de contamination dans les couches du sol. En mesurant l'impédance de la matière en divers endroits, tel que les profondeurs x et x + Δ x, ou à divers moments x + Δ x, puis en déterminant la conductivité G et la capacitance C à partir des impédances mesurées, et, enfin, en déterminant le rapport des dérivés de la conductivité et de la capacitance par rapport au temps, il est possible d'utiliser le rapport de dG(x) et dC(x) en tant qu'indicateur de la composition de la matière. Il a été établi que, de manière surprenante, lorsque l'on détecte la présence de contamination dans le sol, ce rapport est principalement déterminé par la composition naturelle du sol et ne varie pas beaucoup sur une distance relativement réduite. Des changements non naturels survenant dans le rapport dG(x)/dC(x) indiquent donc la présence de certaines substances, tel que des contaminants.
PCT/NL1996/000276 1995-07-14 1996-07-04 Procede et appareil permettant de determiner la composition d'une matiere et de detecter la presence de polluants dans le sol WO1997004305A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU63200/96A AU6320096A (en) 1995-07-14 1996-07-04 Method and apparatus for determining a material composition such as the presence of pollutants in a soil

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1000812 1995-07-14
NL1000812 1995-07-14

Publications (1)

Publication Number Publication Date
WO1997004305A1 true WO1997004305A1 (fr) 1997-02-06

Family

ID=19761320

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL1996/000276 WO1997004305A1 (fr) 1995-07-14 1996-07-04 Procede et appareil permettant de determiner la composition d'une matiere et de detecter la presence de polluants dans le sol

Country Status (2)

Country Link
AU (1) AU6320096A (fr)
WO (1) WO1997004305A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2334586A (en) * 1998-02-20 1999-08-25 Protimeter Plc Moisture sensing probe

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986005278A1 (fr) * 1985-03-08 1986-09-12 Regents Of The University Of California Procedes et appareils dielectriques pour classification in situ du sol
WO1992007251A1 (fr) * 1990-10-12 1992-04-30 Keith Watson Detecteur d'humidite et de salinite et procede d'utilisation
US5148125A (en) * 1989-03-03 1992-09-15 Lincoln College Dielectric constant monitor
DE4311064A1 (de) * 1993-04-03 1994-10-06 Lang Apparatebau Gmbh Verfahren zur Messung der Schmutzbefrachtung einer Waschflotte
EP0649016A1 (fr) * 1993-10-19 1995-04-19 Dow Corning S.A. Procédé de test d'impédance électrique

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1986005278A1 (fr) * 1985-03-08 1986-09-12 Regents Of The University Of California Procedes et appareils dielectriques pour classification in situ du sol
US5148125A (en) * 1989-03-03 1992-09-15 Lincoln College Dielectric constant monitor
WO1992007251A1 (fr) * 1990-10-12 1992-04-30 Keith Watson Detecteur d'humidite et de salinite et procede d'utilisation
DE4311064A1 (de) * 1993-04-03 1994-10-06 Lang Apparatebau Gmbh Verfahren zur Messung der Schmutzbefrachtung einer Waschflotte
EP0649016A1 (fr) * 1993-10-19 1995-04-19 Dow Corning S.A. Procédé de test d'impédance électrique

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2334586A (en) * 1998-02-20 1999-08-25 Protimeter Plc Moisture sensing probe
US6076396A (en) * 1998-02-20 2000-06-20 Protimeter Plc Moisture sensing probe

Also Published As

Publication number Publication date
AU6320096A (en) 1997-02-18

Similar Documents

Publication Publication Date Title
US4219776A (en) Method and apparatus for measuring in situ density and fabric of soils
Gardner et al. Soil water content measurement with a high-frequency capacitance sensor
US3746975A (en) Measuring characteristics of materials by using susceptive and conductive components of admittance
DE69709896T2 (de) Grenzschicht-niveaumessung
Noborio Measurement of soil water content and electrical conductivity by time domain reflectometry: a review
Tarantino et al. Field measurement of suction, water content, and water permeability
Wyseure et al. Measurement of volumetric water content by TDR in saline soils
US4996490A (en) Microwave apparatus and method for measuring fluid mixtures
RU2115935C1 (ru) Способ бесконтактного измерения диэлектрической постоянной диэлектрического вещества
EP0549157B1 (fr) Appareil et méthode pour la mesure du pourcentage de l'eau
EP0575312A1 (fr) Detecteur de niveau et de compositions de liquides et procede
CA2105878C (fr) Methode pour mesurer les melanges eau-huile a teneur en gaz relativement elevee
US6664793B1 (en) Fluid presence and qualitative measurements by transient immitivity response
CA1103329A (fr) Traduction non-disponible
JP3820522B2 (ja) 有機液体物質による土壌の汚染を検出する方法
Hamed et al. Evaluation of the WET sensor compared to time domain reflectometry
WO1997001090A1 (fr) Procede de mesure de la teneur en eau de supports de cultures
WO1997004305A1 (fr) Procede et appareil permettant de determiner la composition d'une matiere et de detecter la presence de polluants dans le sol
RU2740869C1 (ru) Система и способ для наблюдения по меньшей мере одного характеристического свойства многофазной текучей среды
CA1319395C (fr) Identification de fluides et interface entre fluides
EP0216474B1 (fr) Sonde pour mesurer et/ou exercer un contrôle en fonction de la grandeur d'une caractéristique d'un matériau et méthode pour utiliser cette sonde
EP0116116B1 (fr) Compensation des effets d'entrefer dans des sondes à courant de Foucault
GB2246866A (en) Borehole water content logging system and method
Singh et al. Measurement of moisture content with a penetrometer
JPH0552798A (ja) 水分計用センサー並びにそのセンサーを用いた水分測定方法

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): AL AM AT AU AZ BB BG BR BY CA CH CN CZ DE DK EE ES FI GB GE HU IL IS JP KE KG KP KR KZ LK LR LS LT LU LV MD MG MK MN MW MX NO NZ PL PT RO RU SD SE SG SI SK TJ TM TR TT UA UG US UZ VN AM AZ BY KG KZ MD RU TJ TM

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): KE LS MW SD SZ UG AT BE CH DE DK ES FI FR GB GR IE IT LU MC NL PT SE BF BJ CF CG CI CM GA

DFPE Request for preliminary examination filed prior to expiration of 19th month from priority date (pct application filed before 20040101)
121 Ep: the epo has been informed by wipo that ep was designated in this application
REG Reference to national code

Ref country code: DE

Ref legal event code: 8642

122 Ep: pct application non-entry in european phase
NENP Non-entry into the national phase

Ref country code: CA