WO1991010123A1 - Procede et dispositif de detection des particules dans les milieux en ecoulement - Google Patents
Procede et dispositif de detection des particules dans les milieux en ecoulement Download PDFInfo
- Publication number
- WO1991010123A1 WO1991010123A1 PCT/SE1990/000858 SE9000858W WO9110123A1 WO 1991010123 A1 WO1991010123 A1 WO 1991010123A1 SE 9000858 W SE9000858 W SE 9000858W WO 9110123 A1 WO9110123 A1 WO 9110123A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- light
- rings
- detector
- particles
- laser
- Prior art date
Links
- 239000002245 particle Substances 0.000 title claims abstract description 92
- 238000000034 method Methods 0.000 title claims description 10
- 238000001514 detection method Methods 0.000 title claims description 7
- 238000009826 distribution Methods 0.000 claims abstract description 9
- 239000011521 glass Substances 0.000 claims description 11
- 230000003287 optical effect Effects 0.000 claims description 6
- 230000000977 initiatory effect Effects 0.000 claims 1
- 239000003546 flue gas Substances 0.000 description 14
- 239000000428 dust Substances 0.000 description 10
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 9
- 238000005259 measurement Methods 0.000 description 9
- 239000007789 gas Substances 0.000 description 5
- 230000001419 dependent effect Effects 0.000 description 4
- 238000000149 argon plasma sintering Methods 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 241000196324 Embryophyta Species 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 230000003628 erosive effect Effects 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 230000035945 sensitivity Effects 0.000 description 2
- 235000008694 Humulus lupulus Nutrition 0.000 description 1
- 244000025221 Humulus lupulus Species 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 150000001768 cations Chemical class 0.000 description 1
- 230000002950 deficient Effects 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000012631 diagnostic technique Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000007620 mathematical function Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000011514 reflex Effects 0.000 description 1
- 239000004449 solid propellant Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
- G01N15/0211—Investigating a scatter or diffraction pattern
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
- G01N15/02—Investigating particle size or size distribution
- G01N15/0205—Investigating particle size or size distribution by optical means
- G01N2015/0238—Single particle scatter
-
- 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
- G01N2021/4711—Multiangle measurement
- G01N2021/4716—Using a ring of sensors, or a combination of diaphragm and sensors; Annular sensor
Definitions
- the described device comprises an instrument for the con ⁇ tinuous detection of particles in flowing media.
- the detec ⁇ tion relates to particles above a certain size or within a certain size interval, the sensitivity increasing with in ⁇ creased size of the particles.
- a typical field of appli ⁇ cation is the measurement of the erosion capacity of par ⁇ ticles, also called erosiveness, in flue gases for gas tur ⁇ bines .
- the described phenomenon is an example of Fraunhofer diffraction of light .
- the pattern created is called diffraction pattern.
- the magnitude of the angles through which the light is deflected is determined by the size of the particles, which in this case is conside ⁇ rably greater than the light wavelength. At a larger dis ⁇ tance, the pattern is large compared with the cross-section area of the original beam.
- the non-deflected light will be concentrated at a focal point on the optical axis of the light.
- the light deflected by a dust particle forms conical surfaces of light which extend from the dust particle and light up the screen with light rings centered around the focus, separated by dark rings.
- Movement of the light-deflecting particles does not influence the diffraction pattern, since parallel light beams are always focussed on the axis and a given conical angle of deflection always results in the same radial displacement (s) in the focal plane of the deflected light.
- the angle of deflection is given by s/f, where f is the focal distance of the lens.
- the state of the art for measuring the size of dust particles is based, inter alia, on the use of a laser beam which is caused to pass the region where a study of the occurrence of particles and particle size is to be carried out.
- a plate with photo-sensitive diodes is placed in the focal plane of a lens which collects the light to the plate. Fraunhofer diffraction occurs at a large distance from the scattering source, but with the aid of a lens the pattern created may be studied at close hand.
- Particles of a certain size give rise to light rings with known radii and intensities. The light intensities in different rings are measured with photosensitive diodes.
- the collected measured values then provide information about the occurrence of particles, the size and quantity of the particles.
- Known equipment aims at measuring either the total mass or the size distribution of the particles in a flowing medium. Measurement of the total mass of particles in many cases provides insufficient infor ⁇ mation about the composition of particles.
- Another technique is to make use of square detectors, available on the market, with a large amount of photodiodes collected in a matrix. By collecting the measured values from photodiodes which are located at the same mutual distance from the centre of the detector plate, the same function can be obtained as with the ring detectors described.
- Simple, reliable instruments for continuous measurements over longer distances for example wide flue gas channels, which are designed to give alarm on the occurrence of particles above a certain size or within a certain size range, do not exist.
- No general particle measurement instrument is required here, but a device which is able to warn when too high contents of relatively large particles occur.
- Gas turbines may be used for extracting residual energy from flue gases in power plants fired with solid fuels .
- an instrument has been produced. This instrument is to warn when large particles above a certain size or within a certain size interval are detected.
- the measured light power in one single detector ring is a function of the diameter of a light scattering particle according to the formula above. In principle, one ring would be sufficient as such to provide information as to the size of the analyzed particle. The problem is that it is impossible to determine whether the measured light power emanates from one single large particle or from many minor dust grains, each of which scatters light and cooperates to form the measured value of the light power.
- J ⁇ (x) A + Bx 2 + Cx 4 + ...
- the received light power may be written as
- each preceding term is much greater in magnitude than the succeeding term.
- the light power value Pi is dominated by the term Aid 4 and the light power value for the second detector ring P 2 by the term A 2 d . If the detector rings are formed so that all sub-factors in the constants Ai and A2 are influenced to make Ai and A2 equal, the diffe ⁇ rence in received light power will be
- Pi - P2 (Bi - B 2 ) ⁇ . d 6 + (Ci - C 2 ) • d 8 + ...
- the difference signal formed from the two detector rings with the value Pi - P2 is dependent both on the total number and the size distribution of the particles in a manner which makes the measured value of the difference signal a good measure of the total erosiveness of the particles in, for example, a gas turbine.
- a measure of only the size distribution of the particles independently of the total number of particles within the measuring volume.
- the invention is based partially on known technique.
- a laser is mounted on the side of a flue gas channel.
- the beam from the laser passes a windowed opening into the flue gas channel, extends perpendicular to the flue gas flow and continues at the other side surface of the flue gas channel out through a similarly windowed opening in the channel.
- the light then hits a lens provided with a small oblique mirror at the front in the centre.
- the mirror deflects the concentrated, unbroken laser beam to the side, whereas the lens focusses light deflected by the dust particles onto a plate provided with photosensitive diodes, the task of which is to detect incident light powers of the light falling on the diodes.
- the novelty in this invention resides in the fact that measurement is performed in only a small number of detector rings, which may be achieved by utilizing a difference signal according to the above.
- the method used provides rapid information about the occurrence of the sought particle size. It utilizes relatively simple components, therefore becomes comparatively inexpensive, and is simple to handle compared with other equipment available on the market.
- the useful measuring distances for the instrument can be made several times longer than what is technically and economically reasonable with prior art methods.
- Figure 1 shows the relationship between recorded light power as a function of particle diameter, partly for a detector ring, partly for the difference power from detector rings positioned in pairs, all shown on a logarithmic scale.
- Figure 2 show curves which illustrate the relationship between received light power as a function of particle size for two detector rings with different diameters but with the same area.
- SA SE Figure 3 shows a schematic arrangement of all the components included in the device. In addition, the path of the light through the units is also shown.
- Figure 4 shows an arrangement of the measuring device, in which the output power from the laser is measured in an alternative manner.
- a preferred embodiment of a device for detection of undesired particles in flue gases will be described with reference to Figure 3.
- the light from a laser 1 first hits a spatial filter with a beam expander 2 which expands the beam and focusses this at a desired distance beyond the far edge of the flue gas channel, where the beam passes out from the channel through a window 3.
- a beam stop 4 is applied at the centre of the window 3 or, alternatively, at the centre of the lens 6, to divert the central light beam.
- the beam stop is formed as a mirror, which deflects the beam for further analysis .
- a light scattering dust particle 5 diverges the beams which fall upon it.
- the scattered light is collected in an achromatic double lens 6, passes through an interference filter 7 and thereafter illuminates the detector rings .
- the generated signals are forwarded to an electronic unit 9 for forming a difference signal, which provides information about the particle size.
- the somewhat oblique window 10 on the laser side which window is antireflex-coated only on the flue gas side, reflects light to a grey filter 11 which removes 99% of the incident light . After passage through an interference filter 12, this light is allowed to fall on a detector 13, which then provides information about the transmitted light power.
- Grains of dirt on the glass 10 may also give backscattering. Such light is collected by an interference filter 14 with a lens 15 and is measured with a detector 16. Any fouling of the glass 10 may then be recorded here.
- Transmitted light power from the laser can also be measured by an alternative arrangement of the equipment according to Figure 4.
- a beam splitter 21 in the form of a thin glass window is placed in the path of the laser beam at an angle of 45° to this.
- the reflex from the window, one side of which is antireflex-coated, is allowed to fall on a photodetector 22, which then provides information about the optical output power of the laser.
- the beam splitter is placed ahead of the spatial filter 2, any disturbances of the laser light from the oblique glass in the beam splitter then being filtered off before it is allowed to penetrate the measuring volume.
- the concentrated light beam which has been deflected by the beam stop 4 is first allowed to hit an oblique grey filter 17, which reflects a small and variable part of the light to a fiber-optic cable 18.
- the light from the fibre optics 18 is returned to one of the detector rings 8 to give both of these rings an equal amount of background light.
- the light which penetrates the grey filter 17 illuminates, after passage through an interference filter 19, a quadrant detector 20.
- the grey filter has filtered off 99.9% of the original light.
- the detector 20 gives information about transmitted power in combination with detector 13 or, alternatively, detector 22. Deficient centering and alignment can be read out with a detector 20.
- Calibration of the measuring equipment is carried out with the aid of a calibration glass which is placed at a definite distance in front of the lens, for example at the numeral 5, in Figure 3.
- Each calibration glass has been coated with particles of a definite size. This has been achieved by- dropping identical particles of a known size, suspended in a liquid, out onto glass plates. Four or five different sizes of particles which well cover the measuring range are suitable to utilize.
- the calibration glasses are placed in holders . When specific calibration glasses with known particle sizes are placed in the laser beam, the measuring equipment is trimmed for the best correspondence between measured values and the known particle sizes of each calibration glass.
- the grey filter may be replaced by a beam splitter, a semi-transparent mirror, etc.
- mirrors may be used, other light sources than lasers may be utilized, and it is also possible to replace photodiodes with other light-sensitive elements, such as photo-multipliers.
- the instrument may, of course, incorporate more than one pair of detector rings.
- the difference signal from, for example, different pairs of detector rings may control electronic units separately, the output signals thereof then being compared or weighed together.
- the device may be used also for other applications than what has been described here, for example for the detection of suspended particles in liquids or in other fields where it is desired to monitor a corre ⁇ sponding presence of dust particles .
Landscapes
- Chemical & Material Sciences (AREA)
- Dispersion Chemistry (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 Analysing Materials By Optical Means (AREA)
- Optical Measuring Cells (AREA)
- Glass Compositions (AREA)
Abstract
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP91502575A JPH05502943A (ja) | 1990-01-05 | 1990-12-20 | 流動媒体内の粒子を検知する方法と装置 |
FI923094A FI923094A0 (fi) | 1990-01-05 | 1992-07-03 | Foerfarande och anordnaing foer detektering av partiklar i ett flytande medium. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9000039-9 | 1990-01-05 | ||
SE9000039A SE465338B (sv) | 1990-01-05 | 1990-01-05 | Saett och anordning foer detektering av partiklar i stroemmande medier |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1991010123A1 true WO1991010123A1 (fr) | 1991-07-11 |
Family
ID=20378173
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1990/000858 WO1991010123A1 (fr) | 1990-01-05 | 1990-12-20 | Procede et dispositif de detection des particules dans les milieux en ecoulement |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0509045A1 (fr) |
AU (1) | AU7057291A (fr) |
CA (1) | CA2072743A1 (fr) |
FI (1) | FI923094A0 (fr) |
SE (1) | SE465338B (fr) |
WO (1) | WO1991010123A1 (fr) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995006238A1 (fr) * | 1993-08-20 | 1995-03-02 | Technische Universiteit Delft | Procede et appareil de determination des caracteristiques dimensionnelles de particules |
EP0848243A2 (fr) * | 1996-12-06 | 1998-06-17 | United Sciences, Inc. | Procédé et dispositif pour la surveillance de particules utilisant une source lumineuse à l'état solide à faisceau dirigé |
DE19912911A1 (de) * | 1999-03-22 | 2000-10-19 | Schako Metallwarenfabrik | Vorrichtung zur Erkennung von Rauch |
WO2003012402A1 (fr) * | 2001-07-27 | 2003-02-13 | Boehringer Ingelheim International Gmbh | Procedes de determination de la repartition granulometrique d'aerosols et dispositif de mise en oeuvre de tels procedes |
CN107941662A (zh) * | 2017-11-10 | 2018-04-20 | 吉林大学 | 一种利用强场激光检测火焰内颗粒物分布的装置与方法 |
WO2019243149A1 (fr) | 2018-06-21 | 2019-12-26 | Koninklijke Philips N.V. | Module de capteur laser avec indication de disponibilité pour utilisation |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0106684A2 (fr) * | 1982-10-15 | 1984-04-25 | Kabushiki Kaisha Toshiba | Dispositif de mesure des diamètres de particules |
EP0207176A1 (fr) * | 1985-06-07 | 1987-01-07 | Fritsch GmbH | Appareil pour la détermination de grosseurs de particules |
WO1988002855A1 (fr) * | 1986-10-14 | 1988-04-21 | North Sea Instruments Limited | Appareil d'analyse de particules |
GB2203542A (en) * | 1987-04-14 | 1988-10-19 | Secr Defence | Measuring particle size distribution |
GB2204678A (en) * | 1987-03-26 | 1988-11-16 | Joshua Swithenbank | Size and velocity measuring instrument for multiphase flows |
-
1990
- 1990-01-05 SE SE9000039A patent/SE465338B/sv not_active IP Right Cessation
- 1990-12-20 WO PCT/SE1990/000858 patent/WO1991010123A1/fr not_active Application Discontinuation
- 1990-12-20 EP EP19910902809 patent/EP0509045A1/fr not_active Withdrawn
- 1990-12-20 AU AU70572/91A patent/AU7057291A/en not_active Abandoned
- 1990-12-20 CA CA 2072743 patent/CA2072743A1/fr not_active Abandoned
-
1992
- 1992-07-03 FI FI923094A patent/FI923094A0/fi not_active Application Discontinuation
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0106684A2 (fr) * | 1982-10-15 | 1984-04-25 | Kabushiki Kaisha Toshiba | Dispositif de mesure des diamètres de particules |
EP0207176A1 (fr) * | 1985-06-07 | 1987-01-07 | Fritsch GmbH | Appareil pour la détermination de grosseurs de particules |
WO1988002855A1 (fr) * | 1986-10-14 | 1988-04-21 | North Sea Instruments Limited | Appareil d'analyse de particules |
GB2204678A (en) * | 1987-03-26 | 1988-11-16 | Joshua Swithenbank | Size and velocity measuring instrument for multiphase flows |
GB2203542A (en) * | 1987-04-14 | 1988-10-19 | Secr Defence | Measuring particle size distribution |
Cited By (15)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO1995006238A1 (fr) * | 1993-08-20 | 1995-03-02 | Technische Universiteit Delft | Procede et appareil de determination des caracteristiques dimensionnelles de particules |
NL9301446A (nl) * | 1993-08-20 | 1995-03-16 | Univ Delft Tech | Werkwijze en inrichting voor het meten van vormeigenschappen van deeltjes. |
US5764358A (en) * | 1993-08-20 | 1998-06-09 | Technische Universiteit Delft | Method and apparatus for determining the shape characteristics of particles |
EP0848243A2 (fr) * | 1996-12-06 | 1998-06-17 | United Sciences, Inc. | Procédé et dispositif pour la surveillance de particules utilisant une source lumineuse à l'état solide à faisceau dirigé |
EP0848243A3 (fr) * | 1996-12-06 | 1999-05-19 | United Sciences, Inc. | Procédé et dispositif pour la surveillance de particules utilisant une source lumineuse à l'état solide à faisceau dirigé |
DE19912911A1 (de) * | 1999-03-22 | 2000-10-19 | Schako Metallwarenfabrik | Vorrichtung zur Erkennung von Rauch |
DE19912911C2 (de) * | 1999-03-22 | 2001-07-19 | Schako Metallwarenfabrik | Vorrichtung zur Erkennung von Rauch |
WO2003012402A1 (fr) * | 2001-07-27 | 2003-02-13 | Boehringer Ingelheim International Gmbh | Procedes de determination de la repartition granulometrique d'aerosols et dispositif de mise en oeuvre de tels procedes |
US7247496B2 (en) | 2001-07-27 | 2007-07-24 | Boehringer Ingelheim International Gmbh | Process for determining the particle size distribution of an aerosol and apparatus for carrying out such a process |
US7453556B2 (en) | 2001-07-27 | 2008-11-18 | Boehringer Ingelheim International Gmbh | Process for determining the particle size distribution of an aerosol and apparatus for carrying out such a process |
CN107941662A (zh) * | 2017-11-10 | 2018-04-20 | 吉林大学 | 一种利用强场激光检测火焰内颗粒物分布的装置与方法 |
WO2019243149A1 (fr) | 2018-06-21 | 2019-12-26 | Koninklijke Philips N.V. | Module de capteur laser avec indication de disponibilité pour utilisation |
EP3588055A1 (fr) * | 2018-06-21 | 2020-01-01 | Koninklijke Philips N.V. | Module de capteur laser avec indication de disponibilité pour utilisation |
CN112639438A (zh) * | 2018-06-21 | 2021-04-09 | 通快光电器件有限公司 | 指示使用准备就绪的激光传感器模块 |
US11441998B2 (en) | 2018-06-21 | 2022-09-13 | Trumpf Photonic Components Gmbh | Laser sensor module with indication of readiness for use |
Also Published As
Publication number | Publication date |
---|---|
SE465338B (sv) | 1991-08-26 |
FI923094A (fi) | 1992-07-03 |
SE9000039L (sv) | 1991-07-06 |
SE9000039D0 (sv) | 1990-01-05 |
EP0509045A1 (fr) | 1992-10-21 |
CA2072743A1 (fr) | 1991-07-06 |
AU7057291A (en) | 1991-07-24 |
FI923094A0 (fi) | 1992-07-03 |
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