TriOxmatic® 701

The electrochemical sensors of the TriOxmatic® series

Equipped with a special 25 micron thick membrane, the Model TriOxmatic® 701 features an enhanced resolution and a faster response time. This sensor is ideally suited for low level concentration applications; e.g. measurements of residual oxygen in the de-nitrification of biological sewerage treatment.

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The TriOxmatic® series (ECDO): proved and tested…

ECDO stands for Electrochemical Dissolved Oxygen Sensor. 60 years ago, Clark’s cell was introduced and WTW was among the first manufacturers to advance this principle for water and wastewater applications.

• Well proven technology
• Low investment costs
• Self-diagnosis system SensReg/SensLeck through 3-electrode system

The electrochemical principle
With the electrochemical method the O2 diffuses through the membrane of the TriOxmatic® sensor. The oxygen is transformed in a chemical reaction by using an electrolyte; thereby a current can be measured. The electrical current correlates to the oxygen concentration. For delivering precise results, the sensor will require the following conditions:
• Flow
• Continuous exchange of electrolytes
• Clean membrane

Patented Technology – 3 electrode system
In contrast to conventional membrane covered oxygen sensors equipped with 2-electrode technology, the TriOxmatic® sensor functions with a potentiostatically driven 3-electrode system. In terms of measuring technology, this means that the measuring system has two silver electrodes and a gold cathode (A). One silver functions as a non-current bearing reference electrode (R). And, the other is the live, counter electrode (G). The reference electrode thus displays significantly improved potential constancy, which in turn leads to considerably improved sensor signal stability and thus higher measuring accuracy.

The 3-electrode technology additionally allows precise monitoring of the electrolyte supply, i.e. the system displays when the electrolyte solution needs to be replaced.

Self-diagnosis system
All parts being relevant for the measurement, such as membranes are automatically monitored by the SensReg (used electrolyte)/SensLeck (leakage in the membrane) system. Any occurring incidents will be shown.

Maintenance-free due to special membrane
The membrane or the membrane cap plays a decisive role in all DO measuring techniques. Fouling or mud covering of the membrane or of the cap will affect the measurement reading. Unlike conventional membranes the Teflon membranes used by WTW are highly resistant to fouling. This allows operation without the use of additional cleaning accessories in most cases.

High accuracy
WTW sensors feature extremely low maximum errors of 1% of the measured value (i.e. 0.02 mg/ml at a measured value of 2 mg/ml), regardless of whether measuring in the upper or in the lower range of the instrument.

Stable readings right from the start
All WTW ECDOs provide stable and reproducible readings right from the start:
• No break-in
• No long-term drift
• No zero point drift due WTW‘s patented TriOxmatic® principle.

Analogue Sensor
O2 concentration
0.00 … 20.00 mg/l
0.0 … 60.0 mg/l
(depending upon the selected monitor model)
0.01 mg/l
0.1 mg/l

O2 saturation 0.0 … 200.0%
0 … 600%
(depending upon the selected monitor model)
0.1 %

Ordering Information:
201 644 TriOxmatic® 701 IQ Fast response time digital D.O. sensor for use in wastewater treatment plants, e.g. denitrification, for use with IQ SENSOR NET.
Supplied with accessory kit (ZBK 25i) comprising: 2 exchange membrane heads (WP 25i/2), 50 ml electrolyte solution (ELY/A), 50 ml cleaning solution (RL-AG/Oxi), 1x cathode cleaner (SF 300), without connection cable (SACIQ order separately)

201 676 TriOxmatic® 701-1,5
201 678 TriOxmatic® 701-7
201 680 TriOxmatic® 701-15
201 682V* TriOxmatic® 701-SO



Weight 5 kg
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