Appendix B: Cooling water
B40IB006EN-D
49
Appendix B: Cooling water
The cooling water is required to avoid heat transfer
from the chamber to the goniometer.
TIP: For more information on the installation of the
water supply, refer to chapter 4.6
The cooling water hoses can be connected directly
to the mains water supply provided that the water
quality requirements are fulfilled (see table B.1) and
an appropriate filter is used.
If the cooling water does not fulfill the quality re-
quirements in table B.1, a closed cooling unit must
be used. This unit must contain water of the required
quality.
However, in order to prevent the formation of depos-
its and corrosion in the unit, we recommend the fol-
lowing water quality instead of tap water:
•
Use distilled water.
•
Add 1,68 grams (20 mmol) of NaHCO
3
per liter
of distilled water.
•
Check the pH value; it must be between 8.0 and
8.3.
•
If the pH value is too low, add Na
2
CO
3
to the
mixture until the pH is in the above mentioned
range.
•
If the pH value is too high, add NaHCO
3
to the
mixture until the pH is in the above mentioned
range.
.
Saturation index:
SI = pH - pH’s
Ryznar Index:
RI = 2 pH’s - pH
pH: Is obtained and corrected by the addition of
chemicals as stated before.
pH’s: Is calculated according to
pH’s = (9,3 + A + B) - (C + D)
with the following values:
A = Conversion value of total dissolved material in
milligrams per liter (mg/l)
B = Conversion value of the temperature of the cool-
ing water in degrees Celsius (°C)
C = Conversion value of the calcium hardness (NOT
the total hardness), in German degrees (°D)
(1 °D = 10 mg CaO per liter)
D = Conversion value of the bicarbonate content in
chemical equivalent per liter (1 chemical equiv-
alent/liter = 61 mg/l for bicarbonate)
The conversion values A, B, C and D can be deter-
mined from table B.2.
NOTICE
Risk of damage
Do not use plain de-ionized or bidistilled water!
Table 11-1: Requirements on cooling water
quality
Cooling water
Condition
Remarks
Water quality
Tap water
If suitable.
Saturation index
(see below)
< 1
Ryznar index (see
below)
5.5 to 7.5
Dissolved organic
material
use of
KMnO
4
< 20 mg/l
Chloride
< 250 mg/l
Flow rate
0.7 to 1.5 l/
min
Temperature
15 to 25 °C
Pressure
4 bar max.
Water filter
(supplied with the
Anton Paar flow
controller)
16 µm filter-
ing
Part of the
pressure
reducer.
Table 11-1: Requirements on cooling water
quality
Cooling water
Condition
Remarks
