In laser
diffraction (static light scattering) the scattering pattern, obtained from
illumination of dispersed particles with a laser
beam, contains information about particle size. The interaction between
particles and light is mainly dependent on particle
size, shape, surface roughness and refractive indices of material and dispersing
medium.
For a specific material, the scattering
pattern of a particle
is unique for its size. Deconvolution of the sample scattering
pattern with an optical model such as
Mie or Fraunhofer results in the
particle size distribution.
For analysis request and more information, see also the main website of Delft Solids Solutions: www.solids-solutions.com
The laser diffraction technique is especially applicable for samples with a broad or bimodal distribution and for information on size trends in series of samples. Materials can be characterized in the range of 0.04 to 2000 µm and dispersion can be made in water, organic liquid as well as air. The measurements are performed on a Malvern Mastersizer, Coulter LS 230 or a Cilas 1064. The report consists of a graph showing the cumulative and differential volume distributions and statistics as the mode, mean and median diameter, skewness and kurtosis, standard deviation etc.
laser
diffraction, photon
correlation spectroscopy and light
scattering all give a particle
size analysis in some cases based on brownian
motion. The droplet
size is important for the nozzle design of a spray. The particle size of
a powder is not measured with doppler effect, this needs dynamic
light scattering or static light scattering which gives the particle
size distribution with fraunhofer diffraction.
laser diffraction
is a dynamic
light scattering technique that gives the particle size distribution and
droplet size analysis.
The laboratory of Delft Solids Solutions
makes measurements of
particle size distributions of powders and characterization of sprays. laser
diffraction is widely used for spray nozzle design, special spray adapters
are available. Particle
size distribution analysis is rapid and accurate.
Particle size distribution
on malvern instruments or use of pids technology with dispersion of submicron
samples on the beckman coulter or even sympatec gives a characterization according
to the principles of dynamic
light scattering.
Photon
correlation spectroscopy is a static
light scattering technique for submicron
particle size analysis in low concentration.
Beckman Coulter makes products
that are used in hospital laboratories, physicians' offices and group practices.
The company provides a variety of laser
diffraction systems for medical research, drug discovery and biotechnology
applications.
The LS Series is a system of multifunctional particle characterization tools.
Its patented state-of-the-art, laser-based technology permits analysis
of particles without the risk of missing either the largest or the smallest
particles in a sample.
The LS technology is based on both the Fraunhofer and Mie theories of light
scattering. The LS differs from other laser-based instruments by virtue of its
wide dynamic size range, number of size channels and sample measurement options.
The particle size analyzers are the most capable and sophisticated particle
size analyzers available on the commercial market today. In fact, many of the
sub-systems are so unique they're patented, i.e. the patented detector pattern
with 126 optical detectors. The LS uses reverse Fourier lens optics incorporated
in a patented binocular lens system. This enables the LS to optimize light scattering
across the widest dynamic range in a single scan.
Reproducibility is one of the most important factors in laser
diffraction particle size analysis. Tighter product specs allow manufacturers
of bulk and particulate materials to have a higher quality product. And while
the industry standard for reproducibility is 2%-4% under ideal conditions, the
LS Series, typically, has better than 1% reproducibility!
The measurement of particle size is an extremely important parameter across
most branches of industry.
The stability, chemical reactivity, opacity, flowability and material strength
of many materials are affected by the size and characteristics of the particles
within them. Getting things right at every stage of production, from R &
D through to manufacture and quality control of the finished product is vital.
Malvern has a range of sizing solutions from sub-nanometre to millimetres in
size.
Malvern Instruments is the worlds leading supplier of particle sizing instrumentation.
The following pages are a brief user selection guide designed to help you choose
the correct Malvern system to meet your needs. Please note that this is intended
only as a guide. To select the system for your exact requirements, please consult
your local Malvern representative.
sprays are wet, messy,
often highly concentrated, complex and frequently of extremely short duration.
To measure them successfully requires an instrument which addresses these problems
from the design stage through to the laboratory or experimental rig.
Among the major advantages offered by laser
diffraction as a technique for characterizing the droplet
size distributions of sprays
are the rapid acquisition of data for subsequent analysis and a relatively large
measurement volume, coupled with ease of use.
Sympatec is one of the other large particle size instrument manufacturer. It
mainly uses Fraunhofer and is used for characterization of powder
and spray.
light
scattering techniques - laser diffraction - photon
correlation spectroscopy - phase doppler
velocimetry - electrical techniques
- electrical sensing zone - optical
techniques - scaning electron microscopy
- other particle analyses - gravitational
sedimentation - sieve analysis homepage