German WTW FDO 701 (SW) dissolved oxygen electrode weighing approximately 1500gProduct Introduction:

1. Adopting Intelligent Thin Film Calibration (IQMC), no calibration is required;

2. C2 speed correction, high measurement accuracy;

3. Green light (GLT), long lifetime of fluorescent cap;

4. Equal path length reference system (EPRS), stable measurement without drift;

5. 45 degree design, unaffected by bubbles;

6. Unfilled electrolyte;

7. No low flow rate requirement.

German WTW FDO 701 (SW) dissolved oxygen electrode weighing approximately 1500gWorking principle

(1) A layer of fluorescent dye is covered on the thin film at the top of the sensor. When a short wavelength light is irradiated onto the fluorescent dye, it emits long wavelength red light when it returns from the excited state to the ground state. The red light is the test signal. The higher the concentration of dissolved oxygen, the shorter the duration of red light. By testing the duration of red light, the concentration of dissolved oxygen can be determined. The fluorescence based dissolved oxygen sensor has the following drawbacks:

1. The longer the film is in contact with water, the greater the signal drift

2. Fluorescent dyes are prone to aging after exposure to blue light

3. Sensors are more sensitive to bubbles

(2) With over 60 years of manufacturing experience, WTW has successfully overcome the above difficulties and launched the second generation of fluorescence based dissolved oxygen sensors. The technological advantages of second-generation sensors are mainly reflected in the following aspects:

1. IQMC technology: Each diaphragm undergoes strict calibration before leaving the factory, and the calibration data is stored in the chip on the diaphragm.

2. EPRS and other optical path reference systems: testing optical path and reference optical path, as well as symmetrical optical path systems, can synchronously eliminate the effects of optical component aging. Ensure high testing accuracy within the lifespan of the sensor.

3. GLT green light: Green light has a slightly lower energy compared to blue light, which can avoid the fading effect of fluorescent dyes and extend the service life of the film, usually up to 2 years.

4. 45 degree test: The sensor does not adopt a flat structure, but has a 45 degree slope, which can avoid the accumulation of bubbles and solve the problem of being easily disturbed by bubbles.

5. C2 light speed calibration: Fluorescence method ultimately boils down to the issue of testing time, so WTW's time testing system strictly calibrates according to the physical constant of light speed, ensuring accurate time testing.

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