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Particle Size Particle ShapeParticle concentrationAnalyzer

EyeTech

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A new technology for measuring particle size

in combination with particle shape and concentration.

COMBINED LASERTECHNOLOGY & DIA

- New laser technique for measuring particle size

and concentration

- Dynamic Image Analysis for particle characterisation

Content

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In laboratory and production environment

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Why Particle Size Analysis?

Particle size controls many important product characteristics, such as:– Viscosity– Flow-ability– Sedimentation– Optical Properties– Impact/Compressive strength– Agglomeration

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What is the size of a particle?

Size Related Properties :V = VolumeW = WeightS = Surface AreaA = Projected AreaR = Sedimentation Rate

Conventional techniques derive particle size from a (physical) property.

Usually Particle Size is expressed as the diameter of a sphere with similar property -> equivalent sphere

D min

D max

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Equivalent Sphere

These diameters are fundamentally different for the same particle.The equivalent diameters differ for any non-spherical material.Thus, every PSA technique yields different results for non-spherical materials

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Conventional PSA Techniques

The measurement of particle properties has several drawbacks:

- Sphere is an extreme particle shape, not reflecting real particles- Significant errors for non-spherical particles- Particle size results dependent on used technique- Some Instrument response requires calibration depending on the technology used

- Particle size analysis limited to the measured property

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A Modular Particles Analyzer for measuring

� Size

� Shape

� Concentration

in all phases

EyeTech

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EyeTech Measurement Principle

Single Instrument – Dual Measurement Channels

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The EyeTech performs high resolution particle size &

shape analysis and calculates concentration.

The EyeTech combines two methods of analysis:

Laser channel: particle size measurement & concentration

Video channel: shape characterization by acquiring

images of moving particles and analyzing them with

Image Analysis software

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EyeTech Measurement PrincipleSingle Instrument – Dual Measurement Channels

Range lens A: 0.1-300 µm

Range lens B: 10-3600 µm

LASER CHANNEL

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EyeTech Measurement Principle

The rotating laser beam scans single particles within its focus.

The diameter of the particle is directly correlated to the duration of the obscuration.

The principle measurement is a time interval, not an intensity measurement.

The time domain is independent of particles’optical or physical properties

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EyeTech Measurement Principle

From the duration of the obscuration (t) and the knownrotation velocity of the laser beam (v) the particle diameter(D) can be calculated:

D = v . t

In relation to the high speed of the rotating laser, the particles are stationary. So, particle movement does noteffect particle size measurement.

No requirement for pre-knowledge of:- Refractive index - Temperature- Viscosity variation - Electrical conductivity

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EyeTech Pulse Analysis;Off-Center rejections

Pulse Profile

Off-Center

Pulse Transition

Derivative Profile

Pulse Transition

On-Center

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EyeTech Pulse Analysis; Derivative Pulse Signal

Minimum width and maximum amplitude indicate on-center interactions.

Amplitude

For accepted particlecrossings, the anglebetween the particleboundaries and the laser beam approaches90°.

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EyeTech Pulse Analysis; Out-of-Focus rejections

Pulse Profile

Derivative Pulse

Focused Laser Beam

Derivative Pulses too wide;

Out-Of-Focus pulses are

rejected

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EyeTech Pulse Analysis Concept; Transparent Particles

Opaque Particles Translucent Particles Transparent Particles

Pulse Profile

Particle Size Measurement is independent of particle’s transparency

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Concentration Measurement

Only legal pulses are collected in an optical volume

(defined by the thickness of the laserspot, the focus

depth of the lens and radius of circular movement of

the laser) giving the possibility to calculate

CONCENTRATION

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-No pre-knowledge of sample necessary Refractive/Absorption Index, etc.

- Single Particle SizingDetection of minor fractions

-Applicable to a large variety of samplestransparent, translucent, opaque, airborne, liquidborne

-Possibility of time dependent measurements Crystal growth, dissolution properties

-Concentration measurementsize and concentration at same time � kinetic analysis

Application Advantages

Direct laser measurement

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EyeTech Measurement Principle

Single Instrument – Dual Measurement Channels

DYNAMIC IMAGE ANALYSIS CHANNEL

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Reasons for DynamicImage Analysis

• Seeing is believing, See your particles.

• Better characterization of your materials.

• Detection and quantification of shape influences.

• Validation technique for the laser Channel or other particle size equipment.

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EyeTech Video Channel

• Video Channel collects digital images used for:– Visualization during laser measurement– Dynamic Shape Analysis– Grabbing Images and Recording Movie

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Dynamic Image Analysisthe way it is done

� Real time images of particles in motion are collected

420 µm

18 µm

Image Conversion

� Images are converted into a grid containing a collection of picture elements (pixels). Each individual pixel has a value for brightness (grey level):

0 = Dark; 255 = White.

� All images are analyzed according to a pre-defined set of Image Analysis characteristics.

� Measurement is finished when the measurement end condition is met (#of particles/images, confidence level,time)

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Dynamic Image Analysis

• For each individual particle, size and shape parameters are determined.

• The EyeTech Image Analysis software automates set-up and measurement.

• EyeTech software includes many IA procedures such as:– Pre-processing procedures– Image Filters– Region of Interest– Out-of-focus Rejection– Morphology Operations– Grouping according to size/shape– (Re-)processing of stored images and movies

– Lens Calibration

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Dynamic Image Analysis

• Pre-ProcessingImage quality can be improved using automatic pre-processing procedures, e.g.: Contrast Enhancement:

Contrast Enhancement increases the number of gray levels

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Image Analysis TermsBasic Image Analysis terms:

Macro Size Descriptors

Ferret Diameters

Determination of distributions of:- Minimum Ferret- Maximum Ferret- Average Ferret

Average Ferret diameter:

F1 + F2 + F3 + F4 … F36 36

For a sphere size = diameter

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Image Analysis TermsBasic Image Analysis terms:

Macro Size Descriptors

�Perimeter

�Equivalent Diameter

This parameter gives the diameter of a circle of

equal area to the object.

�Specific Length

This parameter gives the average length along a

sinus-like object (fiber) and is given by the

formula:

π

AreaDiameterEquivalent *2=

)Area*16-Perimeter² (Perimeter*¼ +=ngthSpecificLe

Spe c ific Le ng th S pe c ific Le n g th

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Shape Analysis TermsBasic Image Analysis terms:

Macro Shape Descriptors

[ min Ferret diam.]

Aspect Ratio = --------------------------

[ max Ferret diam.]

[Area * 4 π]Shape Factor = ------------------(Circularity) [Perimeter]2

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DSA ParametersComparing Shape Factor to Aspect Ratio

Shape Factor Aspect Ratio

1 1

<0,1 1

0,785 0,707

0,604 0,577

0,436 0,250

0,160 0,100

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Image Analysis TermsShape Descriptors

Additional Parameters:• Over 40• User defined• ÌSO-parameters• Elongation• Curl-index• Modification Ratio• Compactness• Roughness• Wadell’s Sphericity• Solidity• Convexity• Average Concavity• Fractal Dimensions

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Parameters

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• No difference in particle size distributions fordifferent materials

• With Dynamic Image Analysis, the differenceis evident

Quantifying equivalent diameters

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Quantifying shape differences

• The difference in the shape factor and maximum Ferret diameter are obvious!

Max. Ferret Diameter:

Shape Factor:

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Application Advantages

Particle classification using strategic shape filters Selection of particles of interest by their shape in a large matrix

Dynamic Shape Analysis

Accurate determination of agglomeratesSpecific shape of agglomerates are used to select them

Visualization and characterization of foreign particlesSelection of foreign particles by their shape

More accurate characterisation of non-sphericalRods, fibers, Aggregation, Foreign Particles