ABB's Magnos28 Oxygen analyzer delivers unprecedented accuracy

Highly accurate, rapid measurement of oxygen content is vital in a wide range of process industries, from industrial gas production to steel manufacture.

Hear Gary Egerton Business Development & Process Analytics Sales Manager of ABB Measurement & Analytics tells us about ABB’s new Magnos28 analyser and how its radically new structure and manufacturing methods ensure unprecedented accuracy and high response rates.

The new microwing technology offers unprecedented repeatability and precision, giving users confidence in controlling their process. A new digitally based manufacturing process ensures quality so that every sensor made offers a consistent performance.

Designed to be robust and offer reliable operation, the sensor reduces downtime, while also offering increased selectivity for complex gas streams. A rapid response ensures tighter and faster control of the process, making it ideal for when oxygen concentrations change rapidly.

Its high-definition measurement abilities offer improved accuracy at high and low concentrations, giving more precise control of the process. The ability to set individual measuring ranges also allows the analyser to be easily tailored to specific measurement requirements. The analyser also provides long term stability, with calibration of the zero-point with ambient air or nitrogen required only once a month in most applications.

The Magnos28 offers improved drift stability, helping to realize very low measuring ranges of from 0 to 0.5 vol%. With improved sensitivity at very low oxygen concentrations, it offers drastically reduced moisture influence, while its response to other dia- and paramagnetic gases matches theoretical values, reducing measurement uncertainty.

An ingenious system of internal gas flow management directs the process gas instantly to the highly responsive microwing, giving up to a 15 percent improvement in response time. Its internal chamber volume is reduced by factor of three. Combined with completely redesigned gas paths and optimized drillings, this results in rapid gas exchange.

For extra speed there is also a special version offering a rise time of less than 1.3 seconds, making it one of the fastest magneto-mechanical oxygen sensors available. A minimum required gas flow of only 0.15 l/min makes the Magnos28 the perfect choice for processes with rapidly changing oxygen concentrations.

Minimizing external influences delivers unprecedented resolution. A wide dynamic range and high suppressed ranges are achieved by an immediate 32 bit A/D conversion next to the physical sensor, minimizing signal noise. This improves performance across complete 0.5 to 100 vol% O2 range.

Reduced temperature and pressure effects are achieved by a gas flow bypass system thermally decoupled from the sensor block. This ensures defined internal flow and minimizes influences on the detector temperature balance. Intelligently arranged sensors also detect and compensate for external influences.

The Magnos28 is produced using the latest digital manufacturing technology, enabling sub-micrometer precision to ensure each device performs to specification.

This completely new approach is ideally suited to paramagnetic oxygen measurement. It allows the analyser to have a very low mass and high width-to-thickness ratio, together with an optimized magnetic field distribution in the measurement position.

Employing tolerances one-hundred times smaller than the width of a human hair, the microwing is automatically positioned and bonded to a platinum wire. This accuracy gives perfect alignment in the center of the magnetic field, with all processes carried out under absolute clean conditions to give maximum reproducible quality.

Each step is tightly controlled and verified, ensuring accurate production of each sensor. The patent pending sensor balancing process, together with the laser ablation process that etches off miniscule amounts of wafer coating, avoids the need for complex manual tasks conducted using a microscope.

Careful selection of inert materials minimizes drift and significantly improves solvent resistance - neither glue nor solders are used within the core of the Magnos28, while special coatings protect sensitive parts, such as the pole shoes.