COSA Xentaur Hygrocontrol Type 83 - Manual (Page 7)

HYGROCONTROL Manual for Type 83 Page - 6 -
10% - mixed LiCl and ZnCl
2
solution
20, 35, 50, 65, 80, 95% - unsaturated LiCl solutions
The marked relative humidities relate to a temperature of 22°C and
do have a temperature dependency. The accuracy of the solutions at
22°C is +/- 0.5%, they are not toxic and are not dangerous to the
environment.
To assure the easiest handling and highest accuracy, the solutions
are enclosed in glass ampoules, which should be opened only before
usage. Opening is simplified by the weakened middle part of the
ampoules. Once opened the solutions may catch humidity from or
give humidity to their environment - so the time of usage is restricted
and they should be used for one calibration only.
5.2.3. Calibration Chamber
The calibration chambers we are supplying under No. 1810 (or 4716
for 12 mm diameter probes) are hermetically sealed chambers which
consist of three parts:
1) Main part with thread for coupling with probe tip
2) Removable bottom to put the solution in
3) O-ring to give tight connection between parts 1) and 2).
The chamber is made from Aluminium to achieve
a) Temperature equilibrium
b) easiest cleaning procedure.
Mechanical dimensions of the chamber are optimised to form a
closed body without edges. By this form a quick and stable
atmosphere of the desired relative humidity over the solution is
guaranteed.
Due to the temperature dependency of rel. humidity over salt
solutions, you should maintain a constant temperature of 22°C with
deviations of not more than 1°C. This can be done by placing the
probe in an area free from draughts, direct sunlight, radiators and
any other factors that might cause temperature fluctuations. Place
the instrument on an insulating base such as polystyrene and assure
that the instrument, calibration chamber and solutions are at the
same temperature before starting a calibration.
5.2.4. Mounting the Calibration Device
First remove the filter from the tip of the probe. The chamber may now
be screwed to the thread of the probe. The bottom of the chamber is
removable and it is here that the textile pad and the solution are to be
placed. To avoid improper humidity values, always clean the bottom
of the chamber thoroughly: use new pads, and new solutions.
Ensure that the calibration chamber faces downwards, to avoid direct
contact of the solution with the sensor. Before inserting the bottom
into the chamber, unscrew the chamber slightly, to help escaping air,
when you close the chamber. Tighten the chamber again after
closing!