Product description
CCS240/241
8
Hauser
1
4
5
6
7
8
2
3
A0037109
1
Fixed cable
2
Sensor shaft
3
O-ring
4
Large anode, silver/silver chloride
5
Gold cathode
6
Measuring chamber
7
Membrane cap with dirt-repellent membrane
8
Screw cap for securing the membrane cap
3.1.1
Measuring principle
Chlorine dioxide levels are determined in accordance with the amperometric measuring
principle.
The chlorine dioxide (ClO
2
) in the medium diffuses through the sensor membrane and is
reduced to chloride ions (Cl
-
) at the gold cathode. At the silver anode, silver is oxidized to
silver chloride. Electron donation at the gold cathode and electron acceptance at the silver
anode cause a current to flow which is proportional to the concentration of chlorine dioxide in
the medium. This process does not depend on the pH value over a wide range.
The transmitter uses the current signal to calculate the measured variable for concentration in
mg/l (ppm).
3.1.2
Effects on the measured signal
Flow
The minimum flow velocity of the membrane-covered measuring cell is 15 cm/s (0.5 ft/s).
When using the CCA250 flow assembly, this corresponds to a flow rate of 30 l/h (7.9 gal/h)
(upper edge of float at level of red bar mark).
At higher flow rates, the measured signal is virtually flow-independent. However, if the flow
rate falls below the specified value, the measured signal depends on the flow.