English (GB)
7
5.1 Functional principle of measurement
• Sample water is taken at a representative position and passed
to the measuring cell via an integral filter.
– The water flow rate can be adjusted on the measuring cell.
– A float switch serves to signal a sample water deficiency and
for example trigger an alarm.
• Part of the water is taken from the measuring cell and routed
through the three-electrode assembly.
– The agent to be determined (Cl
2
) is converted at the
noble-metal electrode.
• The material to be determined generates an electric current:
– in the µA range
– proportional to the concentration of the parameter Cl
2
(total
chlorine)
– The measuring cell is controlled by a potentiostat integrated
into the measuring amplifier.
– An exactly defined potential of the working electrode is
retained by means of the third electrode (reference
electrode). This results in a linear response for the
measuring cell as well as a stable zero point for the
measurement.
• The measuring amplifier Conex
®
DIA:
– amplifies the current
– calculates it using the calibration parameters
– displays the concentration as a numerical
value
– controls a gas dosing unit or a dosing pump as final control
element.
A water sample without buffer solution can be taken at the sample
water tap. This tap is located before the measuring cell.
6. Technical data
6.1 Used chemicals
The following chemicals are used:
• 91835799 (549-300), buffer solution: ready for use
• buffer solutions consumption: < 360 ml/day
– One container lasts about two weeks.
For further data, see the installation and operating instructions
enclosed with the components.
6.2 Dimensional sketch / drilling diagram
Fig. 2
Dimensional sketch
Measured
parameters
Free chlorine
Sample water
temperature
0 °C to +40 °C
Inlet pressure
0.2 bar - 6 bar (free outlet)
Permissible
ambient
temperature
+5 °C to +40 °C
Sample water flow
rate
Minimum 4.5 l/h
Wetted parts
materials
PMMA, PVC, steel, PTFE, EPDM
Electrode materials Glass, PVC
Connections
Inlet: for PVC tube 6/12 mm or PVC pipe
12 x 1.2
Outlet: for PVC tube 6/12 mm
or PVC pipe
12 x 1.2
Sensitivity
< 10 ppb
Accuracy
< ± 5 % of full-scale value
Repeatability
< ± 3 %
Response time
T
90
approximately 60 seconds
Measuring range
for measuring
parameter Cl
2
0 - 20.0 mg/l
T
M
03
71
19
4
5
0
6
