ENDRESS+Hauser's new optical oxygen sensor, Oxymax W COS61, offers significant benefits in terms of long-term stability with minimal maintenance.
The accurate and continuous measurement of the concentration of dissolved oxygen (DO) is critical in water management applications such as sewage treatment and water treatment plants, fish farming and monitoring river and surface water.
The heart of the Oxymax W COS61 sensor is an optical lens containing fluorescence-active molecules and when excited by a short-wave light pulse, the molecules emit a red light, the intensity and duration of which depends on the DO concentration. No liquid flow is required as the optical sensor takes accurate measurements even in still water.
Delivered as a pre-calibrated sensor, COS61 can be immediately installed at the measuring point without running-in time or on-site calibration.
Self-monitoring alerts the user when a sensor cap needs replacement, typically every 14 months or more, a process that takes a few minutes. With the new cap in place, the sensor may be easily calibrated in air.
Apart from a measuring range of 0 to 20mg/L, COS61 also features digital signal processing, which allows impressive cable lengths of 100m to the transmitter. This allows the transmitter and operator to be situated at a much safer distance away from the process being monitored.
The older amperometric diaphragm sensors are highly maintenance intensive since they tend to become contaminated by H2S or NH3 and require a running-in time before stable values are generated.
By comparison, Endress+Hauser's COS61 optical oxygen sensor needs to be accessed for maintenance three or more times less often.
Since COS61 is built on the standard 40mm design, it can directly replace the older amperometric diaphragm sensors. Retrofitting costs are therefore minimised and existing transmitters, flow assemblies and immersion tubes may continue to be used.