M Series

Panametrics aluminumoxide moisture probe
Applications

FeaturesThis Panametrics aluminum oxide moisture sensor probe
measures moisture concentration in gases and nonaqueous liquids from trace to ambient levels. It is designed
to be used in conjunction with all Panametrics moisture
analyzers for industries including:• Intrinsically safe when used in conjunction with certified
electronics or zener barriers• Petrochemical• Natural gas• Industrial gas• Semiconductor• Furnace gas/heat treating• Power generation• Air dryer• Pharmaceutical• Aerospace• Superior sensitivity, response speed and calibration stability• Optional temperature sensor• Calibrations traceable to national standards• Designed for in situ applications or in conjunction withsample conditioning systems• True absolute humidity sensor• Wide dynamic range

Panametrics hygrometer systems
and moisture probes
Panametrics aluminum oxide moisture probes have set thestandard of performance and value in industrial moisturemeasurement for more than 40 years.
In use, M Series moisture probes are coupled to Panametrics
hygrometer consoles by an interconnecting cable. Easeof use, wide measurement range and rigorous calibration
standards make these systems the preferred choice forindustrial moisture measurement worldwide.

Superior performance
Film thickness of the oxide layer is critical to the performanceof this type of sensor. Panametrics manufactures sensors
with an oxide film thickness that causes them to exhibit true
absolute humidity, rather than relative humidity response.
This critical film thickness also gives the M Series probe quick
response and exceptional calibration stability.

Rigorous calibration standards traceable tonational standards
Each Panametrics aluminum oxide sensor is individuallycalibrated in one of the world’s most advanced moisturecalibration facilities. Developed over several decades, thisfacility uses flow, temperature and pressure measuring
devices, traceable to national standards, to generate
precisely known moisture concentrations to which eachprobe is exposed during the calibration process.
All data is gathered and stored by a dedicated computer
system. Calibrations are repeated over a period of months
to determine the stability of each individual moisture probe.
Only those probes that meet Panametrics demanding
specifications for accuracy and stability are shipped tocustomers.

Theory of operation in gases and liquids
The direct measurement of water vapor pressure isaccomplished easily and effectively in both gases andliquids by the M Series aluminum oxide moisture sensor. The
sensor consists of a porous oxide layer over which a very thincoating of gold is evaporated. The base and the gold layer
form the two electrodes of what is essentially an aluminumoxide capacitor. Water vapor is rapidly transported throughthe gold layer and equilibrates on the pore walls of the oxidelayer. The number of water molecules absorbed on the oxide
structure determines the conductivity of the pore walls. Eachvalue of pore wall resistance provides a distinct value ofelectrical impedance, which in turn is functionally related to
the water vapor pressure. This functional relationship holds
for measurements made in either gas phase or liquid phase.

Installation flexibility
M Series probes are designed to be located at the process,exactly where the measurement is needed. Cable length
between the probe and hygrometer may be 2000 ft (610 m)
or more. Pressure range is from vacuum up to 5000 psig (345bar) with no minimum flow requirements. Sample cells make
M Series probes easy to install, and the cells are available ingeneral purpose, Type 4 weatherproof, and Type 7 explosionproof housings.
Remote installation of the probe and wide operating
parameters minimize measurement lag time and thepotential for sample contamination associated with longsample runs back to an analyzer. This feature is extremely
important in the measurement of very low moisture content
or where rapid changes occur.
When the integrity of the measurement is threatenedby conductive or erosive particles, or adverse process
conditions, sample conditioning will be required. Panametrics
manufactures turnkey sample-conditioning systems thatmaintain the integrity of the sample’s moisture content whileremoving the contaminants. These designs have been fieldtested and have proven to be reliable, while requiring little orno maintenance.

Specifications
Moisture probe
Intrinsic safety
Intrinsically safe when connected to a Panametrics Moisture
Series analyzer, PM880 portable hygrometer or intrinsicallysafe barriers in accordance with the user’s manual.
M Series moisture probe:
BAS01ATEX1096X
II 1 G EEx ia IIC T4 (-20°C to +80°C), and CSA C US Class I,
Division 1, Groups A,B,C&D T4, LR44204-23
European compliance
Complies with EMC Directive 2014/30/EU and PED 2014/68/EUfor DN<25
Type
Aluminum oxide moisture sensor
Calibration
Each probe is individually computer calibrated against
known moisture concentrations, traceable to national
standards.
Dew/frost point calibration ranges• Overall capability: 140 to -166°F (60 to –110°C) by request• Standard calibration range: 50 to -112°F (10 to –80°C) withdata provided from 68 to -166°F (20 to -110°C)• Ultralow calibration range: -58 to -148°F (-50 to –100°C)
with data to -166°F (-110°C)

Accuracy• ±3.6°F (±2°C) above -148°F (–100°C)• ±5.4°F (±3°C) below -148°F (-100°C)

Repeatability• ±0.4°F (±0.2°C) above -148°F (–100°C)• ±0.9°F (±0.5°C) below -148°F (–100°C)

Temperature• Operating temperature: -4°F to +140°F (–20°C to +60°C)• Storage temperature: -22°F to +158°F (–30°C to +70°C)
Operating pressure (dependent on mount)• Flange process connection (M1):
5 µHg to 75 psig (6 bar)
• Threaded process connection (M2):
5 µHg to 5000 psig (345 bar)
Flow range• Gases: Static to 10,000 cm/s linear velocity at 1 atm• Liquids: Static to 10 cm/s linear velocity at a density of 1 g/cc

Input voltage
1 VAC, 77 Hz

Optional temperature sensor
TypeNonlinear negative temperature coefficient (NTC) thermistor(resultant temperature linearized by microprocessor)

Panametrics, a Baker Hughes business, provides solutions in
the toughest applications and environments for moisture,oxygen, liquid and gas flow measurement.
Experts in flare management, Panametrics technology also
reduces flare emissions and optimizes performance.
With a reach that extends across the globe, Panametrics’
critical measurement solutions and flare emissions
management are enabling customers to drive efficiency
and achieve carbon reduction targets across criticalindustries including: Oil & Gas; Energy; Healthcare; Water andWastewater; Chemical Processing; Food & Beverage andmany others.

Operating range–22 to 158°F (–30 to 70°C)
Accuracy±0.9°F (±0.5°C) overallResponse time (maximum)
1 second in well-stirred oil or 10 seconds in still air for a 63%
step change in increasing or decreasing temperature

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(05/2021)

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