PMA50 EEX

Application

Due to the extremely fast response time of the patented M&C magneto-dynamic meas­uring cell with no stagnant volume as well as the negligible cross sensitivity from other sample gas components, the portable M&C oxygen analyser PMA 10S does not normally limit its use for a wide variety of applica­tions where oxygen purity measurements are essential.

Description

The PMA 10S oxygen purity analyser, being an extended version of the PMA 10, is provided with an electronic suppression system which enables oxygen purity measureents within the expanded 99-100 vol.% range.

This measuring range is displayed on the analogue meter whilst the digital indicator remains for the 0- reading.

The electronic zero suppression system may be selected by means of a push button switch which is located on the control panel of the instrument.

The PMA 10S analyser can normally be used also for its standard PMA10 functions. Oxygen purity measurements could only be made discontinuously. The measuring accuracy of the analyser can be maintained when calibra­tion of the instrument with a certified gas takes place before the measurement proce­dure in order to avoid influence of ambient temperature and pressure. A measurement of 1 vol.% can be easily realized whilst the maxi­mum value remains at 100 vol.%. Other meas­urement within this range can be performed.

– Further technical data see leaflet PMA10, 13.1. –

Measuring principle of M&C ox­ygen analyser

The PMA 10S utilises the paramagnetic principle of operation to measure oxygen concentrations. The analyser measures the paramagnetic susceptibility of the oxygen in the sample gas by means of the M&C magneto-dynamic measuring cell. The physi­cal propertys which distinguishes oxygen from other gases is its paramagnetism. It is significantly higher comparing to other com­mon gases. This operation principle is one of the most accurate and reliable procedures to determine the oxygen concentration in a gas mixture from 0 to 100 Vol.%. The robust M&C cross-flow cell has no stagnant volume. Advantages are the fast response time, the flow rate up to 60 l/hr, the small volume of 2 ml, the extremely low drift, the absolute linearity and the negligible cross sensitivity against other sample gas components. With a proper sample conditioning and pressure, the M&C cell will never need replacing. The dumbbell with a small mirror at its centre is mounted in a strong inhomogenous magnet­ic field. The paramagnetic oxygen strength­ens the forces on the diamagnetic dumbbell and causes a shifting which is detected by a system consisting of light beam, mirror and a photo cell. A compensation current is induced via the feedback coil on the dumb­bell and leads to a reset of the dumbbell into its zero-position.

The required current is linearly proportional to the oxygen concentration