Ozone gas analysis with the ULTRA.sens®
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Ozone gas analysis with the ULTRA.sens® based on selective UV light-emitting diodes Figure 1: ULTRA.sens® ozone measurement module with integrated auto-zero function (AZF) Ozone O3 is an unstable gas that is formed by adding energy with oxygen. The service life (half-life) of ozone is approx. 20-100 hours, after which it decomposes back into oxygen O2. Ozone must therefore be produced in an ozone generator before use. Appropriate gas sensors are required to control the ozone concentration. Until now, toxic mercury vapour lamps have been used as the radiation source in these gas sensors. Wi.TecSensorik GmbH has now succeeded in developing a gas sensor based on UV LEDs that is mercury-free and delivers excellent measurement results. Ozone is used to sterilise surfaces, water and air, as it is a strong oxidising agent and therefore kills viruses, bacteria, fungi, etc. Its intense odour makes it perceptible even in very low concentrations (<<1ppm). The odour threshold is around 0.02 ml/m³ (0.02 ppm). Ozone measuring devices must therefore be able to detect even the smallest concentrations in the ppb range. With the ULTRA.sens® AK250, measuring ranges of 01000ppb O3 can be realised with a detection limit of <5ppb O3.

NDUV ULTRA.sens® Wi.Tec-Sensorik GmbH uses a special UV photometer (ULTRA.sens®) for this purpose, which utilises different UV light-emitting diodes (UV LEDs) as radiation sources in the range from 230 nm to 400 nm. In the UV photometer, the gas sample to be analysed is irradiated by pulsed UV radiation and the proportion of absorption in the cuvette is measured. The concentration in the cuvette can be calculated very precisely from this absorption using the Lambert-Beer law. This calculation is supplemented by additional algorithms so that the analysis result is independent of the current...

Figure 2: Gas flow diagram with upstream auto-zero function (AZF) Figure 3: ULTRA.sens® with a 25 mm long analyser cuvette (AK25) in process version (stainless steel) for detecting high ozone concentrations in the vol.% range. Data Sheet: ULTRA.sens O3-Gasanalyse Wi.Tec-Sensorik GmbH Schepersweg 41-61 D-46485 Wesel Germany