Malvern Instruments Spraytec, User Manual

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These alarms can be used to guard against two possibilities:
.
High spray concentration – in some applications the spray concentration is
too high for accurate results to be obtained. This situation is detected using
the
Min Transmission warning and error level values.
.
Low spray concentration – in some applications the spray concentration
may be too low for accurate results to be obtained. This situation is de-
tected using the
Min Scattering warning and error values.
Set the Warning threshold in the first column and the Error threshold in the
second column. When a threshold is reached, a warning or error symbol will be
shown in the record views and the Size History view.
The parameters in the dialogue are:
.
Use Default Values – if this is selected a set of default alarm settings is
used for measurements. In most cases these allow routine measurements to
be made. If measuring very concentrated or very dilute sprays, the user may
need to enter custom alarm values, so they must deselect this check box.
.
Min Transmission (%) – sets the minimum transmission which will be
accepted as part of a measurement. If the measured transmission falls below
the Error level set here, no Particle Size Distribution is calculated. This er-
ror occurs at high spray concentrations.
.
Min Scattering – relates to the average scattering intensity recorded across
the active detectors. If the average scattering falls below the Error level set
here a particle size distribution is not calculated. This error occurs at very
low spray concentrations.
Spray profiles
The Spray profile options let the user define the path length of the laser beam
through the spray. This is the distance through the spray plume that the laser
beam travels. It allows the spray concentration to be calculated accurately.
An advanced option allows users to specify the spray plume geometry, improving
the accuracy of data analysis. The user can define the shape, size, and position of
the spray plume in relation to the measurement zone.
$
To use a Spray profile:
While creating an SOP or using manual measurement:
.
On the first Analysis dialogue click the Edit... button under Data han-
dling .
.
Select the Spray Profile tab. This initially has a default path length set:
C H A P T E R 1 0
S p r a y t e c
P a g e 1 0 . 1 2
M A N 0 3 6 8