O2X
DUO
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Introduction
The O2X DUO sensor is designed to continuously measure dissolved oxygen levels in
liquids. The O2X DUO is effective in saving energy costs associated with aeration
systems in an activated sludge process. In addition, accurate measuring of dissolved
oxygen allows for better control of nitrification/denitrification.
The O2X DUO features two different principles of measuring; Clark Cell electrode or
optical cell. See section 3 below.
1.
A few words about this manual
This manual details installation procedures and operational features of the Cerlic O2X
DUO sensor. Menu navigation and technical data for the BB1/BB2 control box can be
found in the BB1/BB2 service manual
.
2.
Design
The O2X DUO sensor is manufactured with SS2343 (316SS) stainless steel. Built-in
flushing nozzles allow for the most accurate readings with little maintenance. The
electronics is protected in the rugged casing, ensuring its reliability in very demanding
environments.
The sensor has a fixed, shielded 10 m (33’) M12 cable used for signal transmission
between the sensor and the BB1/BB2 control box. The cable sheath is made of Hytrel
and is highly resistant to aggressive materials and fluids.
3.
Measuring principle
Clark cell,
The electrode is a Clark type electrode with FEP membrane . The Clark cell
detects the oxygen though its reduction at the Gold electrode. The sensor consists of a
Gold cathode and Silver anode. A membrane covers the gold & silver electrodes and
blocks access of solids to the electrodes. Only dissolved gases such as oxygen can pass
thru the membrane, hence the reduction current responds to the oxygen concentration.
Active components included in the electrode are treated to maximize their life span.
Inside the electrode there is also a temperature sensor mounted in a way that minimizes
problems with temperature adjustments. This provides compensation of the electrode
due to temperature changes. There is a connector on the electrode for the O2X amplifier
cable. The temperature can be read on the BB1/BB2 and can be used as secondary
signal when an O2X sensor is configured to use two mA outputs. The temperature
measurement is not a precision measurement but should rather be seen as an indication.
Optical cell,
The optical cell is using phase shift technology to determine the oxygen
concentration. A special coating is applied to the acrylic disc in the top of the optical
electrode and called sensor cap in the manual. The optical cap is not sensitive to UV
light, but it is recommended when doing an air calibration to have the sensor in the
shade. The Clark & Optical cells can be interchanged in the O2X DUO sensor but an
air calibration must be preformed. There is a connector on the electrode for the O2X
amplifier cable. The temperature can be read on the BB1/BB2 and can be used as
secondary signal when an O2X DUO sensor is configured to use two mA outputs. The
temperature measurement is not a precision measurement but should rather be seen as
an indication.