KROHNE OPTISYS CL 1100 EN - Manual (Page 40)

7
TECHNICAL DATA
40
OPTISYS CL 1100
www.krohne.com 01/2013 - 4002492301 - MA OPTISYS CL 1100 R02 en
Ozone measurement
Ozone (O
3
) is an instable molecule of three oxygen atoms and a very strong oxidizing agent. At
room temperature it is a gas. Due to its instability it cannot be stored in pressurised cylinders
and has to be prepared on site.
O
3
is an eco-friendly disinfectant. However, its great disinfection strength can only be used to
good advantage in suitable reactors with a sojourn time of at least 3 minutes. The long-term
effect of O
3
is only a few minutes.
O
3
is measured potentiostatic with measuring and counter electrodes of pure gold and an
Ag/AgCl reference. The measurement shows good selectivity towards ozone. A precise potential
is applied to the measuring electrode, leading to an accumulation of negative charges on the
metal surface. O
3
molecules that hit the surface take a defined portion of the charge with them.
The controller measures the potential between measuring and reference electrode and
readjusts the charge on the electrode surface. The current necessary to maintain a constant
charge is a direct measure for the concentration of O
3
. The sensor design with 3 electrodes in a
single rod enables us to use our patented cleaning procedure ASR (patent Dr. A. Kuntze)
providing you with a low-maintenance measuring setup.
Ozon measurement
Figure 7-4: Ozon measurement
1 Reference electrode
2 Voltage measurement
3 Current needed to maintain the constant potential
4 Counter electrode
5 Measuring electrode