OEM Paramagnetic Oxygen Gas Sensor Modules
The concept of paramagnetic oxygen gas sensor measurement principle lies within the fact that the oxygen atom has paramagnetic nature, 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. The Parox1200 paramagnetic oxygen sensor series developed by Angst and Pfister Sensors and Power is based on the measurement of force that is required to keep a nitrogen filled glass dumbbell under a magnetic field at its original position. The electrostatic force required to keep the dumbbell at its original position is directly proportional to the oxygen concentration.
The output signal of the Parox1200 paramagnetic oxygen sensor has practically no cross sensitivities from other gases. Another main feature of the Parox1200 paramagnetic oxygen sensor module is its very low drift over time, which is achieved by a combination of a heated cell (55°C), matching the right materials and a pre-defined burn-in phase at the application. The signal repeatability is better than ±0.03 %V O2 and the zero-point drift is lower than ±0.1 %V O2/week. Every single module goes through a 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 Parox1200 paramagnetic oxygen sensor module. All these features along with long lifetime, fast response and recovery times and low maintenance, makes Parox1200 the obvious choice for analyzing gas mixtures with gases that would potentially destroy or falsify the signal in most of the other types of oxygen sensors.
The Parox1200 series paramagnetic oxygen sensor is extremely compact. The sensor 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 out let gas connection ports in either 3 mm or 1/8” size. The sensor has a design of almost perfect cubic with dimensions 80x78x93 mm and a weight of just over 1 kg. The Parox1200 paramagnetic oxygen sensor module has configurable measurement ranges, with a standard of 0-25%V O2. The broad configurable measurement range of Parox makes it very useful for oxygen generator applications, where tough tolerance requirements are needed. Alternatively, the Parox series has a standard output signal of 4-20 mA linear with an option of having voltage based linear signal (0-1V, 0-4V and 0-10V).
The most popular application, among many, for the Parox1200 series paramagnetic oxygen sensor module is in excess oxygen analysis/ exhaust monitoring in virtually all types of combustion systems “Continuous Emission Measurement System” CEMS. In the combustion process in power plants, combined heating plants or steel production, the atmospheric oxygen O2 reacts with fuel. During combustion, undesirable pollutants are produced, such as CO and NOX. By measuring the O2 content, the combustion can be optimized and the formation of pollutants as well as fuel consumption can be reduced. This minimizes operating costs and protects the environment. The Parox1200 sensor measures the oxygen concentration independent of the concentration level of all other gases present in a combustion process application.
Another popular application for the Parox1200 series 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 Parox1200 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.
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.
