Vaisala K-PATENTS PR-43, Руководство пользователя

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The refractive index n
D
changes with the process solution concentration and temperature. For
most solutions the refractive index increases when the concentration increases. At higher
temperatures the refractive index is smaller than at lower temperatures. From this follows that
the optical image changes with the process solution concentration as shown in the figure
below. The color of the solution, gas bubbles or undissolved particles do not affect the
position of the shadow edge (C).
B B
C C A A
Low concentration High concentration
Figure 28 Optical images
The position of the shadow edge is measured digitally using a CCD element and is converted
to a refractive index value n
D
by a processor inside the instrument. This value is used together
with the measured process temperature to calculate the concentration.
Figure 29 From image detection to concentration
PR-43 Series User Guide M212455EN-B
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