Advanced Paramagnetic Oxygen Transmitter

The APX Advanced Paramagnetic Oxygen Transmitter is specially designed with advanced background gas compensation that makes it suitable for applications with defined or undefined hydrocarbon gases including vapor recovery, flare gas and refinery gas.

The unit's advanced background gas compensation not only measures the thermal conductivity of a gas, but the heat capacity and viscosity as well. By measuring these extra variables, it is better equipped to differentiate background gases that have the same thermal conductivity, such as nitrogen and ethylene. This gives the APX the advantage over other meters to reliably measure oxygen in a broader range of applications with known and unknown background gases.

An onboard microprocessor gives the unit the computing power to provide automatic oxygen signal compensation and integrated signal-processing algorithms to provide enhanced linearity and accuracy for reliable, long-term measurement.

The APX also has sophisticated error-checking software with user-programmable defaults and error limits to detect abnormal measurement conditions.

It is easily programmed using the multilevel, menu-driven software via an RS232 interface to provide convenient access for changing defaults, analog output scaling and calibration.

Electronic components are housed in a weatherproof/explosionproof transmitter package that can be installed right at the measurement point to simplify wiring and provide trouble-free operation The rugged transmitter has no moving parts, making it insensitive to vibration. Its unique dual-chamber, temperature-controlled cell design provides resistance to contamination and temperature or flow sensitivity.

How It Works
Oxygen's paramagnetic property causes an oxygen-containing gas sample to move within the magnetic field. The gas movement creates a "magnetic wind" that is sensed by the thermistor pairs. Oxygen concentration and background gas compensation are determined by the transmitter's microprocessor.

The APX requires 115-VAC power and provides a 4-20 mA output signal that is fully programmable for zero and span. The output is proportional to oxygen concentration and internally compensated for background gas and/or atmospheric pressure variations.

Panametrics, Inc., 221 Crescent Street, Waltham, MA 02453. Tel: 781-899-2719; Fax: 781-894-8582.