2 Functional Description
Brief functional description
The DULCOTEST
®
Sensor for free
chlorine CLO 1 / CLO 2 is an ampero‐
metric three-electrode sensor without a
membrane. The DULCOTEST
®
Sensor for
free chlorine CLO 1 / CLO 2 can be used
to determine the concentration of free
chlorine in water.
The DULCOTEST
®
Sensor for free
chlorine CLO 1 / CLO 2 measures the
content of hypochlorous acid (HOCl) in
water.
Typical applications:
n chlorination of swimming bath water
(CLO 1)
n chlorination of drinking water (CLO 1)
n combating legionella in house water
installations up to 70 °C (CLO 2)
The sensor signal depends on the con‐
ductivity of the sample medium.
The sensor signal is flow-dependent. The
rate of flow in the DGMA module must
therefore be kept constant at ± 5 l/h.
2.1 Construction
The DULCOTEST
®
Sensor for free
chlorine CLO 1 / CLO 2 is an open, three-
electrode sensor without a membrane. It
comprises a sensor cap and the sensor
shaft. The electrolyte-filled sensor cap
constitutes the reference system. The
ring-shaped reference electrode in the
measuring chamber is above the electro‐
lyte and contacts with the working elec‐
trode (cathode) and the counter electrode
(anode).
Both electrodes on the sensor shaft are
immersed in the measuring (sample)
water. The amplifier electronics are
located in the sensor shaft. The electrical
connection is above this.
The temperature sensor for temperature
compensation is incorporated in the lower
part of the sensor shaft .
2.2 Measured variable
CAUTION!
Oxidising agent
Possible consequence: Slight or
minor injuries, material damage
If there are additional oxidising agents
in the sample medium such as, e.g.
chlorine dioxide, ozone or chloramine
then these are also detected by the
sensor. In other words, the sensor is
not specifically calibrated for chlorine
but detects all oxidising agents in the
sample media.
This should be considered when con‐
figuring the process to prevent incor‐
rect measurement and concomitant
incorrect metering.
Free chlorine (HOCI, OCI
-
, Cl
2
). Free
chlorine is the sum of chlorine gas (Cl
2
),
hypochlorous acid (HOCI) and hypo‐
chlorite (OCI
-
).
Functional Description
14