OEM paramagnetic oxygen gas sensor modules

The parametric measuring principle for oxygen sensing works in a concentration range from ~0% O2 and up to 100% O2. The physics is rather complex, and there are different measurement approaches in order to exploit the fact that the oxygen atom is paramagnetic, because of the two unpaired electrons. Some measurement approaches use a temperature imbalance between thermistor pairs caused by a magnetic wind in order to determine the oxygen concentration. Our principle, used in the OXYPA paramagnetic oxygen sensor module, is quite different; we measure the force that is necessary to keep a pair of nitrogen filled glass dumbbells in a high magnetic field. The force is proportional to the oxygen concentration, because the higher the oxygen concentration, the higher the force needed to keep the dumbbells in place. The output signal from the OXYPA paramagnetic oxygen sensor has practically no cross sensitivities from other gases. This, together with other positive features such as long lifetime, fast response time and low signal drift, makes the OXYPA the obvious choice for analyzing gas mixtures with gases that would potentially destroy or falsify the signal in a zirconia based oxygen sensor.

The OXYPA paramagnetic oxygen sensor module in the Angst+Pfister Sensors and Power product program is compact and of a very high quality. The OXYPA is designed for installation in gas analyzers or gas measurement systems equipped with process control modules, and is a forced flow type of sensor with in- and outlet gas connection ports in either 3 mm or 1/8” size. The design of the OXYPA is almost perfect cubic with dimensions 80x78x93 mm and a weight just over 1 kg.

The OXYPA paramagnetic oxygen sensor module has 5 standard measurement ranges; 0-5%O2, 0-10%O2, 0-25%O2, 0-100%O2 and 80-100%O2. The latter measurement range is very useful for oxygen generator applications, where tough tolerance requirements are needed. The output signal is 4-20 mA linear, optional 0-1 V/0-4 V/0-10 V linear.

The most popular application, among many, for the OXYPA paramagnetic oxygen sensor module for is in excess oxygen analysis/exhaust monitoring applications in virtually all types of combustion systems. The OXYPA measures the oxygen concentration independent of the concentration level of all other gases present in a combustion process application. 

Another popular application for the OXYPA paramagnetic oxygen sensor module is monitoring of the oxygen content in fermentation vessels, biochemical fermenters and sewer gas, where there is a high content of sulfur containing gases. The OXYPA measures reliably and is designed for such harsh environments by using materials, such PVDF, Glass, Steel 1.4571, Gold and Viton, that can all withstand corrosive gases. 

The main feature of the OXYPA paramagnetic oxygen sensor module is the very low drift, which is achieved by a combination of a heated cell (55°C), matching the right materials and a long burn-in phase in the factory. The signal repeatability is better than ±0.03 %O2 and the zero-point drift is lower than ±0.1 %O2/week. Every single module has passed an rigorous quality check that guarantees excellent performance in a given application. The total errors, including tilt, temperature, pressure and flow, are so low and manageable that many customers adapt a plug-and-play & minimum maintenance approach during the installation and operation of the OXYPA module.

If you have any questions, please do not hesitate to contact Peter Felder. 

Product details

Figure 2. Front and backside pictures of the almost cubic OXYPA OEM paramagnetic oxygen sensor module; the backside (left) shows the electrical terminal block connection, the frontside (right) shows the in- and outlet gas connection ports. The signal adjustment ports (zero and full-scale) are also shown in the picture to the right.