The A-20 Scanning Photo Sedimentograph uses the same
principle of operation as the VATSA-99 but is designed for
smaller particle size analysis from sodium down to 0.5 µm. The
A-20 sedimentograph uses the relationship defined in Stoke's
Law between the size of a particle and the speed at which it
sinks in a liquid is used for the determination of the
particle size distribution in sediment samples.
In the scanning photo-sedimentograph, a photometer for
determination of the optical density travels upwards along a
sedimentation cuvette under computer control. The change in
the concentration of sedimenting particles in the liquid is
measured as a function the height and evaluated in a computer
program and the particle size distribution of the sediment
sample is calculated from the values obtained. In order that
the measuring time might be further shortened, the speed of
the "fast scanning" is set so that only that time is required
which is actually necessary to measure even the smallest
particles.
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Menu-assisted analysis proceeds simply and quickly
utilizing computer function keys. Normally, the user will
specify a lower limit for particle size measurement to speed
up time of analysis. Size measurements stop once this limit is
reached, and all remaining sizes are then reported together as
a single quantity. If no limit is selected, distribution is
measured to the instrument's 0.5µm limit. Results may be
screen displayed or printed as tabulations, mass frequency
distributions or as cumulative distribution curves. Samples to
be measured are introduced in the 200 ml sedimentation tank (cuvette)
of the measuring unit.
Model A-20 comes complete with measuring unit and software
for use with a user-provided IBM-compatible computer.
Calibration Standards are dry quartz powders in 10g quantities
complete with certificate of analysis.
503-206 115V Scanning Photo Sedimentograph - A-20 80 lbs.
503-207 230V Scanning Photo Sedimentograph - A-20 80
lbs.
Size Analyzers
