Panametrics M2LW-00-010-0 M2LW M-Series Probe with Thin Film AluminumOxide Sensor

Product Highlights

• Intrinsically safe when used in conjunction with certified electronics or zener barriers
• Superior sensitivity, response speed and calibration stability
• Optional temperature sensor
• Calibrations traceable to national standards
• Designed for in situ applications or in conjunction with sample conditioning systems
• True absolute humidity sensor
• Wide dynamic range

Applications

This 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:

• Petrochemical
• Natural gas
• Industrial gas
• Semiconductor
• Furnace gas/heat treating
• Power generation
• Air dryer
• Pharmaceutical
• Aerospace

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

Film thickness of the oxide layer is critical to the performance of 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.

Each Panametrics aluminum oxide sensor is individually calibrated in one of the world’s most advanced moisture calibration facilities. Developed over several decades, this facility uses flow, temperature and pressure measuring devices, traceable to national standards, to generate precisely known moisture concentrations to which each probe 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 to customers.

The direct measurement of water vapor pressure is accomplished easily and effectively in both gases and liquids by the M Series aluminum oxide moisture sensor. The sensor consists of a porous oxide layer over which a very thin coating of gold is evaporated. The base and the gold layer form the two electrodes of what is essentially an aluminum oxide capacitor. Water vapor is rapidly transported through the gold layer and equilibrates on the pore walls of the oxide layer. The number of water molecules absorbed on the oxide structure determines the conductivity of the pore walls. Each value of pore wall resistance provides a distinct value of electrical 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.

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 (345 bar) with no minimum flow requirements. Sample cells make M Series probes easy to install, and the cells are available in general purpose, Type 4 weatherproof, and Type 7 explosion proof housings.

Remote installation of the probe and wide operating parameters minimize measurement lag time and the potential for sample contamination associated with long sample 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 threatened by conductive or erosive particles, or adverse process conditions, sample conditioning will be required. Panametrics manufactures turnkey sample-conditioning systems that maintain the integrity of the sample’s moisture content while removing the contaminants. These designs have been field tested and have proven to be reliable, while requiring little or no maintenance.