WO2012007542A1 - Procédé et appareil de mesure optique - Google Patents

Procédé et appareil de mesure optique Download PDF

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Publication number
WO2012007542A1
WO2012007542A1 PCT/EP2011/062046 EP2011062046W WO2012007542A1 WO 2012007542 A1 WO2012007542 A1 WO 2012007542A1 EP 2011062046 W EP2011062046 W EP 2011062046W WO 2012007542 A1 WO2012007542 A1 WO 2012007542A1
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WO
WIPO (PCT)
Prior art keywords
light
sample
wavelength
detector
probe
Prior art date
Application number
PCT/EP2011/062046
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English (en)
Inventor
Matthew Rice
James Duncan Holloway
Original Assignee
Matthew Rice
James Duncan Holloway
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 Matthew Rice, James Duncan Holloway filed Critical Matthew Rice
Publication of WO2012007542A1 publication Critical patent/WO2012007542A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/49—Scattering, i.e. diffuse reflection within a body or fluid
    • G01N21/51—Scattering, i.e. diffuse reflection within a body or fluid inside a container, e.g. in an ampoule
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N21/4738—Diffuse reflection, e.g. also for testing fluids, fibrous materials
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/85—Investigating moving fluids or granular solids
    • G01N21/8507—Probe photometers, i.e. with optical measuring part dipped into fluid sample
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
    • G01N21/47—Scattering, i.e. diffuse reflection
    • G01N2021/4704—Angular selective
    • G01N2021/4709—Backscatter

Definitions

  • This invention relates to turbidity apparatus used for measurement of the concentration of a dispersed phase in a fluid. More specifically, this invention relates to a method and apparatus for accurately measuring very turbid samples, such as the fat concentration in dairy cream.
  • the turbidity of a fluid is the cloudiness caused by individual particles (dispersed phase) that are suspended in a fluid (continuous phase) and is a measure of the light scattered by the particles that is characteristic of the number and size of particles present in the sample.
  • Typical examples of turbid samples include emulsions (e.g. milk, cream, personal care products, home care products, deodorants), suspensions (e.g. waste water, deodorant), dispersions (inks, paints, coatings), foams (e.g. shaving cream, hair mousse, personal care products, home care products) and also biological fluids, bacteria, polymer emulsions etc.
  • Turbidity is a commonly employed technique for measuring the
  • Turbidity can be determined by either measuring the attenuation of a light passing directly through a fluid sample or by the measurement of scattered light.
  • turbidity is measured by monitoring scattered light at 90 degrees using a light that is not absorbed by either the continuous or dispersed phase.
  • ISO 7027 specifies 860 nm as the wavelength of the light as this wavelength is least influenced by dissolved light-absorbing substances present in natural occurring waters, while EPA 180.1 and patent publication US 5064590 specifies the light from a tungsten lamp with a peak wavelength of between 400 nm and 600 nm.
  • a wavelength can be chosen that will be absorbed by the dispersed phase.
  • This technique requires that discrete wavelengths of tight are absorbed by the dispersed phase (fat), typically between 2,5 Mm and 10 um.
  • a limitation with this technique is that even low concentration milk samples oft en have very high optical densities; typically a 3,5 % fat milk sample will require an optical path length of 37 um, as shown in patent publication US 4247773, in order to allow sufficient light to reach the optical detector.
  • Patent publication US 3 161768 describes a similar technique and teaches that optical path lengths of 10-100 ⁇ m are required.
  • Patent publication US 6937332 describes an improved turbidity apparatus that can monitor turbid samples up to 10000 NTU using a backscatter detector mounted at 138 degrees from the incoming light path.
  • the backscatter sensing system will extend the range of a conventional turbidity sensing systems when the fluid under evaluation is so turbid that light scattered from the incoming light cannot make it to the light detector.
  • the reason for this is that the detector is placed at a distance from the light source and as a result of multiple scattering; the absorption path-length is sufficiently long that all the photons become absorbed by the media.
  • publication US 6937 332 only extends the operating range to 10000 NTU where it is presumed above this turbidity that no light can make it to the detector.
  • Patent publications EP 0017007 and WO 8809494 describes a backscatter turbidity apparatus whereby the light source is placed in very close proximity to the detector, essentially at 180 degrees to the direction of the incoming light path, further reducing the absorption path-length, using two adjacent parallel optical fibers.
  • samples with turbidities above 10000 NTU can be monitored, such as emulsions tike milk and dairy cream, up to approximately 15 % fat content. Above IS % the output from the analyzer no longer changes and no further discrimination can be made.
  • Patent publication CA 1199813 describes a method and apparatus for measuring the consistency of pulp slurry utilizing dual measurement.
  • This publication teaches the utilization of a two-signal ratio comprising a water sensitive and non-water sensitive wavelength. The purpose of the ratio is to compensate for disturbing factors such as brightness, wood species or chemicals, it is described that the method and apparatus provides a measurement range of 0,05 to 15% in consistency is possible.
  • the present invention aims to remedy the disadvantages and improve on prior art and to provide a method and an apparatus that will provide measurement at high turbidities and/or fat concentrations by reducing the destructive interference of photons entering and leaving the sample matrix.
  • this method we artificially decrease the absorption path- length by selecting a wavelength that is absorbed by the continuous phase of the measurement media. The result is that fewer photons are being scattered back, and therefore the risk for destructive interference is reduced, resulting in an extended measurement range.
  • the present technique has been shown to increase the upper measurement range in dairy cream from 15 % to well over 50 % fat content.
  • an improved backscatter turbidity apparatus which is capable of measuring turbidities well in excess of 10000 NTU.
  • the method for determining the concentration or change in the size of the dispersed phase in a continuous phase comprises the steps of transmitting a light beam into the sample at a wavelength that wiil be appreciably absorbed by the continuous phase, measuring the amount of backscattered light and correlating the measured signal to the concentration of dispersed phase.
  • the backscattered light should be measured at a point that forms an acute angle at the midpoint of the transmitted light with respect to the light source.
  • Fig. 1 is an axial sectional view of a sensor head according to the present invention, which includes a central illuminating optical fiber and a juxtaposed optical fiber for detection of light;
  • Fig.2 is an end sectional view of the optical fiber sensor head as shown in Fig. 1, whereby the illumination and detection optical fibers are at an angle to one another;
  • Fig.3 is an end view of the optical fiber sensor head as used in the device of Fig.1, whereby a plurality of juxtaposed optical fibers are utilized;
  • FIG.4a & Fig.4b diagrammaticairy shows an apparatus according to the present invention
  • Fig.5a & Fig.5b is a schematic and simplified diagram showing the operation and components of the apparatus according to the present invention.
  • Fig.6a & Fig.6b are schematic and partial views of the backscatter of light on
  • Fig.7 is a graphical representation of the signals received on the basis of the fat concentration of a dairy cream sample.
  • Fig. 8 is a graphical representation of the signal received during the whipping of a dairy cream sample.
  • the principles of the present invention are disclosed by way of example by a probe 1 shown in Fig. 1.
  • the probe 1 can be made of any non-corrosive materia! relative to the media in the process. However, preferably the probe 1 is made of stainless steel construction.
  • the probe 1 illustrated in Fig. 1 shows a sanitary TriClamp* process connection which allows the probe to be inserted into a pipeline or the body or wail of a reactor.
  • the probe 1 can incorporate any other type of process connection such as a sanitary thread, Ingold* fitting, pipe thread(BSP, NPT), flange (e.g. DIN, ANSI), Swageiok* fitting , or alternatively, the probe 1 may have no process connection and be inserted or "dipped" into the process media by way of an open vessel or container.
  • optical fibers 2 and 3 for the transmission and detection of light, in Fig.1, the optical fibers 2 and 3 are protected by means of a flexible metal conduit 4.
  • a flexible metal conduit 4 it should be understood that the present invention is not limited to how the optical fibers 2 & 3, conduit 4 and probe 1 are mounted, and this can be done in different ways.
  • These components can for example be mounted by different mechanical means or they can be fastened using suitable glue S that is compatible with the media and conditions of the process.
  • suitable glue 5 would be an epoxy resin.
  • Fig. 1 shows an embodiment of the present invention using two optical fibers, however, it should be understood that the invention can be implemented with one or several optical fibers, and also without optical fibers, as will be shown in other embodiments in the following description.
  • Fig.2 is an end sectional view of the probe 1 as used in the device of Fig. 1, depicts a further embodiment of the present invention whereby the optical fibers 2 and 3 are at an acute angle to one another and are touching at the tip 7 of the probe 1.
  • Such a configuration as depicted in Fig.2 will maximize the amount of backscattered light by reducing the absorption path-length.
  • FIG.3 A further embodiment of the present invention is depicted in Fig.3, illustrating an end view of the probe 1 as depicted in Fig. 1 with a central illuminating optical fiber 9 surrounded by a plurality of juxtaposed detection optical fibers 8a, 8b, 8c ...8n.
  • Such an arrangement would provide greater light throughput and a greater region of process media to be monitored for the same absorption path length.
  • Fig.4a diagrammaticai!y shows an apparatus according to the present invention whereby the light transmitted to and received from the process media occurs via a singular light guide 17 to the measurement probe 1.
  • a light guide 17 may be any compatible material such as a quartz, silica or sapphire optical fiber or even a plastic light guide such as acrylic.
  • a light source 10 providing the necessary measurement wavelength is preferably a LED lamp or laser diode due to the low power requirements and narrow optical emission spectra of such devices, however other suitable devices include incandescent lamps such as halogen, tungsten, deuterium and mercury vapor, as weli as fluorescent lamps, in accordance with the present invention, the wavelength of the incoming light must be chosen that will be absorbed by the continuous phase of the process media.
  • An optical filter 11 can be utilized to obtain the desired optical wavelength and emission characteristics and can be placed either in front of the light source 10 as depicted in Fig.4a, or alternatively in front of the detector 20 as depicted in Fig.4b.
  • the optical filter 11 is a band pass or narrow band pass type of filter; however other filters such as laser line, long pass, short pass and colored glass filters could also be utilized.
  • the optical emission 12 from the light source may vary with temperature and/or aging of the lamp, in which case a reference detector 15 can be utilized to compensate for such variations by splitting the light radiated from the source 12 using a beam splitter 13 that will direct a portion 14 of the primary light to the reference detector 15.
  • the same beam splitter 13 is also utilized to direct light 19 returning from the sample 18 to the measurement detector 20.
  • narrow diameter optical fibers typically between 0,1 micron and a few millimeters, are utilized as the light guide 17, it is preferable to use a collimating lens 16 to ensure a good efficiency of light entering and exiting the optical fiber 17.
  • Fig.4b is a simplified apparatus according to the present invention whereby optical fibers 2 and 3 and light guide 17 as depicted in Figs. l-4a are not present. Instead, the light source 10, optical filter 11 and optical detector 20 are placed in dose proximity to an optical window 21 and, when in use, also close to the sample 18. The light radiated from the source 12 passes directly through the optical window 21 into the sample 18 where it is both scattered and absorbed, the resulting light 19 passes back though the same optical window 21, through an optional optical filter 11 and then to the detector 20.
  • the arrangement depicted in Fig.4b would be the preferred method for configurations whereby the measurement wavelength is not compatible for use with optical fibers, typically x-ray and mid to high infrared.
  • Figs. Sa and 5b are block diagrams showing the components included in the apparatus according to the present invention.
  • an analyzing unit 36 adapted to make the determination based on signals from the detector is utilized, the analyzing unit 36 consisting of numerous electronic and software devices including, but not limited to, a microprocessor, A 0 converter, lamp regulator, keyboard and display unit.
  • Fig Sa depicts a mode of operation whereby the light source 10 is emitting a broad wavelength spectrum with the monitoring of more than one light wavelength in the spectrum for the fight beam 12.
  • a beam splitter 13 is utilized to direct broad spectrum light 19 returning from the sample 18 to two separate measurement detectors 20a and 20b with individual bandpass filters 11a and lib for transmission and finally the detection of only the narrow wavelength spectrum.
  • Fig 5b depicts a mode of operation monitoring at more than one light wavelength by the use of more than one light source 10a and 10b, one light source for the emission of each respective light wavelength, in this mode of operation, each lamp is pulsed and measured alternatively; the procedure controlled and regulated using a microprocessor.
  • the detector 15, 20 utilized may be a device capable of only one electronic output, such as a photodiode, or alternatively, a
  • spectrophotometer capable of simultaneously providing detailed absorption measurements at multiple wavelengths. More than one light source 10, 10a, 10b and optical filter 11, 11a, lib could also be arranged to obtain the required measurement wavelengths. It may be desirable to monitor at multiple wavelengths to simultaneously determine the
  • concentration of more than one compound such as measuring both milk fat ⁇ dispersed phase
  • concentration of proteins dissolved in the continuous phase of a dairy cream sample Another example would be to simultaneously determine the concentration of the dispersed phase and the color of the continuous phase of a highly turbid sample.
  • the detector 15, 20 utilized should be compatible with the desired measurement wavelength corresponding with the light source.
  • a silicon photodiode or photomultipiier may be used, for NIR applications (800-3000 nm) an InGaAs device can be used, for mid-IR wavelengths (3000- 5000 nm) an InSb, HgCdTe or PbSe detector can be used, for long wave infrared
  • HgCdTe devices can be used and for an x-ray source ( ⁇ 200 nm) a photodiode with phosphor coating could be used.
  • the light source 10 and/or detector 20 may either be incorporated as part of the optical probe 1, placed in dose proximity to the measurement point as depicted if Fig.4b, or alternatively placed in a separate housing whereby tight is transferred to the measurement point and back utilizing optical fibers 2, 3 and 17.
  • the two optical fibers 2 and 3 are identical and contiguous to the way shown in Fig. 1.
  • the sample 18 Is illustrated by drdes (not drawn to scale) 23 representing tiie dispersed phase and the background 22 representing the continuous phase.
  • the light entering tiie sample is depicted by the arrow pointing towards 12 the sample via a first optical fiber 2, while tiie light exiting the sample is depicted by an arrow in a direction away from 19 the sample via a second optical fiber 3.
  • the wavelength of the light source is preferably 630 nm which has negligible absorbance for a continuous phase of water.
  • the wavelength of the light source is preferably 630 nm which has negligible absorbance for a continuous phase of water.
  • the multiple scattered light beams 24 only a portion of the light from the first optical fiber 2 will propagate to the second optical fiber 3, and this portion of scattered fight can be correlated to the concentration of the dispersed phase 23 present in the sample 18.
  • Figs.6a and 6b drastically simplifies the path of light by illustrating only one of multiple separate scattered light paths 24 that would occur between the first optical fiber 2 and the second optical fiber 3, however for illustrative purpose, it should be dear that for all possible paths of scattered light, the continuous phase 22 will have negligible influence on the intensity of the light.
  • Fig.6b illustrates the underlying mechanism of the present invention, whereby the wavelength and bandwidth of the incoming light 12 is selected so that the incoming light will be at least partially absorbed by the continuous phase 22 of the measurement medium 18. As illustrated by one of multiple scattered light paths 24, the amount of light 19 propagating from the first optical fiber 2 to the second optical fiber 3 is reduced in Fig.6b due to the absorption of light by the continuous phase 22 of the sample 18.
  • the present invention is not limited to the use of light in tiie visible area.
  • the term "light beam" is used for emitted electromagnetic radiation in any wavelength that could be used to achieve the absorption by the fluid sample.
  • the wavelength spectrum of the light source could vary depending on the implementation of the present invention.
  • the wavelength of the light source can be between 100 and 10000 nm, between 1000 and 10000 nm (IR), or between 1000 and 2000 nm ( NIR).
  • the light source emits light at a near-infrared wavelength, in which case the wide spectrum can be used or a band pass filter can be used to achieve a narrower band spectrum of wavelengths.
  • a prototype of the present invention was built and tested using a dairy cream sample.
  • the probe was constructed identical and contiguous to the way shown in Fig. 1, using a 1" TriClamp* type process connection 1 and two 600 ⁇ m silica optical fibers 2, 3 separated by a distance 6 of 50 ⁇ m.
  • Fig.7 shows a graphical representation of the measurement results of three separate light wavelength configurations with the same dairy cream sample having an initial concentration of 50% fat which was then gradually diluted with water.
  • the probe was evaluated using a wavelength that would be substantially absorbed by the continuous phase of the dairy cream sample.
  • the continuous phase of dairy cream is water which has a strong NIR absorption at 1440 nm.
  • a 1440 nm LED lamp was used in combination with a 1440 nm narrow band pass filter with a 10 nm bandwidth, represented by graph 26 in Fig.7.
  • the probe was also evaluated using a wavelength that would be partially absorbed by the continuous phase of the dairy cream sample.
  • the narrow band pass filter was not used, providing an optical emission wavelength of 1440nm with a 100nm bandwidth, represented by graph 27 in Fig.7.
  • the result of the first test 25 in Fig.7 was the same as the results disclosed in prior art (EP 0017007) whereby from the graph it is evident that the probe has a range up to about 15 % fat concentration, at which a maximum signal is reached the analyzer output no longer changes.
  • the mechanism behind this phenomena is destructive interference between the inbound and exiting photons due to multiple scattering of the inbound photons, and is typical of samples with very high optical density with a large refractive index contrast (difference between the refractive index of the dispersed and continuous phase), and when the inter particle size is less than the wavelength of the light e.g. milk & dairy cream.
  • the detector has lost the ability to discriminate between the individual small particles and only sees them as groups of particles.
  • the probe was evaluated using a wavelength that would be substantially absorbed by the continuous phase of the sample in order to overcome limitations with prior art.
  • the result of the second test 26 in Fig.7 clearly demonstrate a substantial increase in the upper measurement range of the apparatus, whereby the upper range was extended from 15% fat to at least 50 % fat which was the maximum concentration of the fat in the sample under test From the results 26, it is conceivable that substantially higher fat concentrations could also be analyzed.
  • the mechanism behind this phenomenon is the suppression of destructive interference of photons entering and leavingthesamplematrix.
  • the absorption path-length isartificiallydecreased byselectingawavelength that isabsorbed by thecontinuous phaseofthe measurement media resultingin fewer photons beingscattered back, and thereforereducing theoccurrenceofdestructive interference, resulting in an extended measurement range.
  • awavelength was selected thatwould have partial absorption bythecontinuous phaseofthe dairycream sampleby increasingthe bandwidth oftheincominglight. From the results 27, a benefitof this modeofoperation isto extendthelowerrangeofthe apparatus at theexpenseof resolution fromthe upper rangeofthe apparatus. In this modeofoperation 27 itis possible to monitorfrom approximately0,1% fatto at least 50%fat, whitethrough theprevious modeofoperation 26 itwas possibletooperatefrom approximately 2 %to at least 50%fat concentration.
  • the rangeofthe equipmentcould be increased by measuringat morethan onewavelength which would be dependent upon theconcentration ofthesample. From the results depicted in Fig.7, low concentrations,e.g. lessthan 10% milkfat,could be measured usinga non absorbing wavelength 25, while high concentrations, e.g. above 10% milkfat,could be measured using an absorbingwavelength 26or27.
  • Therangecould be manuallyswitched, or alternatively, a microcontrollercould automaticallyswitch between thedesired measurement wavelengths dependingupon theelectronic signals receivedfrom the detector.
  • Fig.8 shows a graphical representation ofa measurementcharacterizingchanges in the particlesizeand distribution for a 40%cream samplethatwaswhipped usingan electronic mixingapparatus.
  • Att* 0 (29 in Fig.8)theelectronic mixingapparatus wasturned on causing airbubblesto become entrapped in thecream sample leadingto a rapid increaseinthe analyzeroutputto a point wherea foam was presenton thetop ofthecream 30.
  • Thefoam graduallydisappeared which was alsonoted by a decreasein analyzeroutput 31, to a pointwhere thefoam was gone32 afterwhich timethecream started tothicken.
  • theanalyzeroutput graduallyincreasedto a point where is reached a constant value 34, shortly after which the cream became suddenly thick at the same time the analyzer output decreased 35.
  • process optimization such as controlling CIP cycles, product identification and quality control.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)

Abstract

Cette invention concerne un procédé et un appareil permettant de déterminer au moins la concentration ou la turbidité d'une phase dispersée en suspension dans un fluide, ledit procédé comprenant l'émission d'un faisceau lumineux (12) en direction d'un échantillon de fluide (18) et la détection de la lumière diffusée (19) par ledit échantillon de fluide (18). Cette invention porte plus spécifiquement sur le choix de la longueur d'onde utilisée pour le faisceau lumineux (12) de façon qu'au moins une longueur d'onde du faisceau lumineux soit absorbée par la phase continue, par exemple, l'eau, de l'échantillon de fluide (18), et l'utilisation de l'absorption dans la détermination de la concentration ou de la turbidité d'une phase dispersée, par exemple, une matière grasse.
PCT/EP2011/062046 2010-07-16 2011-07-14 Procédé et appareil de mesure optique WO2012007542A1 (fr)

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Application Number Priority Date Filing Date Title
SE1050813 2010-07-16
SE1050813-3 2010-07-16

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WO2012007542A1 true WO2012007542A1 (fr) 2012-01-19

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014044474A1 (fr) * 2012-09-20 2014-03-27 Voith Patent Gmbh Sonde de mesure et procédé pour quantifier des propriétés d'une suspension et/ou des substances la composant
WO2018013035A1 (fr) * 2016-07-14 2018-01-18 Brännström Gruppen Ab Procédé et appareil permettant de déterminer la teneur en matières solides dans un milieu liquide

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161768A (en) 1961-01-27 1964-12-15 Nat Res Dev Method and apparatus for the analysis of emulsions and suspensions
EP0017007A1 (fr) 1979-03-31 1980-10-15 Desitek Design und Vertrieb technischer Geräte GmbH Dispositif de mesure de la turbidité, notamment de fluides
US4247773A (en) 1978-12-06 1981-01-27 A/S N. Foss Electric Method for quantitatively determining fat in a fat-containing sample
CA1199813A (fr) 1981-12-07 1986-01-28 Tapio Parviainen Methode et dispositif optique de mesure de l'homogeneite des pates a papier
WO1988009494A1 (fr) 1987-05-27 1988-12-01 Societe Nationale Elf Aquitaine (Production) Dispositif pour la determination d'au moins la concentration de particules solides en suspension dans un fluide
US5064590A (en) 1989-05-26 1991-11-12 The United States Of America As Represented By The Secretary Of The Air Force Method of forming an ultra-thin nonlinear optical film
US5424545A (en) * 1992-07-15 1995-06-13 Myron J. Block Non-invasive non-spectrophotometric infrared measurement of blood analyte concentrations
US6635491B1 (en) * 2000-07-28 2003-10-21 Abbott Labortories Method for non-invasively determining the concentration of an analyte by compensating for the effect of tissue hydration
US6937332B2 (en) 1998-12-16 2005-08-30 Honeywell International Inc. Oil quality sensor

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3161768A (en) 1961-01-27 1964-12-15 Nat Res Dev Method and apparatus for the analysis of emulsions and suspensions
US4247773A (en) 1978-12-06 1981-01-27 A/S N. Foss Electric Method for quantitatively determining fat in a fat-containing sample
US4247773B1 (fr) 1978-12-06 1983-08-09
EP0017007A1 (fr) 1979-03-31 1980-10-15 Desitek Design und Vertrieb technischer Geräte GmbH Dispositif de mesure de la turbidité, notamment de fluides
CA1199813A (fr) 1981-12-07 1986-01-28 Tapio Parviainen Methode et dispositif optique de mesure de l'homogeneite des pates a papier
WO1988009494A1 (fr) 1987-05-27 1988-12-01 Societe Nationale Elf Aquitaine (Production) Dispositif pour la determination d'au moins la concentration de particules solides en suspension dans un fluide
US5064590A (en) 1989-05-26 1991-11-12 The United States Of America As Represented By The Secretary Of The Air Force Method of forming an ultra-thin nonlinear optical film
US5424545A (en) * 1992-07-15 1995-06-13 Myron J. Block Non-invasive non-spectrophotometric infrared measurement of blood analyte concentrations
US6937332B2 (en) 1998-12-16 2005-08-30 Honeywell International Inc. Oil quality sensor
US6635491B1 (en) * 2000-07-28 2003-10-21 Abbott Labortories Method for non-invasively determining the concentration of an analyte by compensating for the effect of tissue hydration

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014044474A1 (fr) * 2012-09-20 2014-03-27 Voith Patent Gmbh Sonde de mesure et procédé pour quantifier des propriétés d'une suspension et/ou des substances la composant
WO2018013035A1 (fr) * 2016-07-14 2018-01-18 Brännström Gruppen Ab Procédé et appareil permettant de déterminer la teneur en matières solides dans un milieu liquide

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