Functional Description; Construction; Measured Variable; Function - ProMinent DULCOTEST CLO 1 Manual Del Operacion

2 Functional Description

Brief functional description
The DULCOTEST Sensor for free chlorine CLO
®
1 / CLO 2 is an amperometric three-electrode
sensor without a membrane. The
DULCOTEST ® Sensor for free chlorine CLO 1 /
CLO 2 can be used to determine the concentra‐
tion 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 instal‐
lations up to 70 °C (CLO 2)
The sensor signal depends on the conductivity 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 electrolyte and
contacts with the working electrode (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.
Functional Description
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 inju‐
ries, 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 cali‐
brated for chlorine but detects all oxidising
agents in the sample media.
This should be considered when configuring
the process to prevent incorrect measure‐
ment and concomitant incorrect metering.
Free chlorine (HOCI, OCI
is the sum of chlorine gas (Cl
acid (HOCI) and hypochlorite (OCI

2.3 Function

Gold wires with a diameter of 2 mm are used as
the working electrode (cathode) and counter
electrode (anode); a silver ring coated with a
layer of silver halide is used as reference elec‐
trode. After the sensor has been electrically
connected to the controller, a potentiostat is used
to ensure there is a constant polarisation voltage
for the required electrode reaction on the working
electrode, independent of the current flow. The
current flow (depolarisation current) produced,
- , Cl ). Free chlorine
2
), hypochlorous
2
- ).
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