GE Sensing APX Specifications

GE

Sensing

APX

Panametrics Advanced
Paramagnetic Oxygen
Analyzer

APX is a Panametrics product.
Panametrics has joined other GE
high-technology sensing businesses
under a new name

_

GE Industrial, Sensing.

Applications

A complete oxygen analyzer typically used in
applications such as:

• Vapor recovery

• Barge loading

• Flare gas

• Refinery gas

• Olefins such as ethylene and propylene

• Pure hydrocarbons

Features

• Advanced background gas compensation for varying
gas mixtures

• Infrared (IR) through-glass keypad for easy
programming in hazardous areas

• Certified for use in hazardous areas

• Resistant to liquid upsets

• No moving parts

• Universal AC input

• Long term calibration stability

• Calibrate in N2only, but use in any background gas

g

Panametrics Advanced Paramagnetic
Oxygen Analyzer

The APX advanced paramagnetic oxygen analyzer is the
newest addition to the Panametrics line of
thermoparamagnetic oxygen transmitters and analyzers.
The APX is specially designed with advanced background
gas compensation that makes it ideal for applications
with defined or undefined hydrocarbon gases, including
vapor recovery, flare gas and refinery gas.

Advanced Background
Compensation

The APX’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
additional physical properties, the APX is better equipped
to differentiate background gases that have significantly
different or varying diamagnetic effects. This gives the
APX an advantage over other, traditional dumbbell
paramagnetic oxygen analyzers, which do not
automatically compensate for the inherent diamagnetic
effects of changing background gases. The result is that
the APX reliably measures oxygen more accurately in a
broader range of applications with either known or
unknown background gases.

Top Performance and Ease of Use

An onboard microprocessor gives the APX the computing
power to provide automatic oxygen signal compensation
and integrated signal-processing algorithms. This
enhances linearity and improves 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, including a
loss of flow to the analyzer or a pressure spike.
The APX is easily programmed through the multilevel,
menu-driven interface, which provides convenient
access for changing defaults, analog output scaling and
calibration.

Rugged Design and
Low Maintenance

Sensor and electronic components are housed in a
flameproof and explosion-proof enclosure with

How It Works

Oxygen’s paramagnetic property causes a gas sample
containing oxygen to move within a magnetic field.
Thermistor pairs, which are part of a wheatstone bridge
circuit, sense the “magnetic wind” created by the gas
movement. The resulting signal, along with heat capacity
and viscosity measurements, is used by the
microprocessor to calculate the oxygen percentage
accurately.

Choice of Ranges

The APX provides a 4 to 20 mA output signal that is fully
programmable for zero and span. The output is
proportional to oxygen concentration and is internally
compensated for background gas and pressure
variations. The APX is available in a wide variety of
measurement ranges.

Dual-Chamber Design

Flow schematic of the APX thermoparamagnetic oxygen measuring cell.
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. Additional sensor
elements are used to measure gas heat and viscosity. Oxygen
concentration and background gas compensation are determined by the
transmitter’s microprocessor.

Induced
gas flow

Upper

measurement

chamber

Upper

flow-through

chamber

Sample

inlet

Sample

outlet

Wind

generating

(cooled)

thermistor

Wind

receiving

(warmed)

thermistor

Magnetic

field

weatherproof protection, allowing installation right at the
measurement point to simplify wiring and provide
trouble-free operation. The unique dual-chamber,
temperature-controlled, oxygen-sensor design provides
resistance to contamination, while minimizing
temperature and flow sensitivity.

GE

Sensing