Michell Instruments XTC601 Specifications

Oxygen & Binary Gas Analyzers

XTC601 Binary Gas Analyzer

Thermal Conductivity Technology in Safe or Hazardous Areas

A robust, linear and stable thermal conductivity analyzer for measurement of binary gas mixes such
as air in hydrogen, nitrogen, argon, helium or carbon-dioxide. The sensor is housed in a rugged
casing, making it suitable for a wide range of applications. When the flame arrestors are fitted, the
analyzer becomes explosion-proof and suitable for hazardous areas.

Highlights

• Suitable for use in ATEX, IECEx, TC TR Ex & CCSAUS
certified Hazardous Areas

• Optional status LEDs following NAMUR standard

• Compact and rugged design with an EExd enclosure and
4-20 mA output

• Touch-screen display allows calibration or adjustment
without the need for a hot works permit

• Accuracy of better than ±2% full scale

• IP66 rated enclosure

• Low cost of ownership due to minimal maintenance

• Ranges available: 0-5 up to 0-100%

• Stability ±0.5% per month (of span)

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Applications

• Hydrogen coolant in electricity turbines

• Product quality in air separation plants

• Syngas production

• Helium recovery

• Fuel cell research

• Gasification

• Product quality such as air in argon for double glazing

• Can be coupled with an XTP601 for measuring oxygen in
varying backgrounds

• Ar or He in food and beverage plants

Oxygen & Binary Gas Analyzers

Biogas Plant

Michell XTC601 Thermal Conductivity Analyzer for Safe or
Hazardous Areas

The XTC601 binary gas analyzer is designed to measure the
percentage of a selected gas in a binary mix. Using thermal
conductivity with high quality thermistors, the sensor is
reliable and highly stable. The analyzer is housed in an
explosion-proof case and is rated ATEX Cat II for use in
hazardous areas. For installation in non-hazardous areas, a
general purpose version is available.

Features

High Sensor Stability Reduces Calibration Costs

The sensor in Michell’s XTC601 binary gas analyzer largely
eliminates drift associated with other comparable devices,
improving the stability of the measurement. This allows
longer calibration intervals and reduces both labor and
consumable costs.

Reliable Long-Term Performance

The thermal conductivity sensor has no moving parts, and is
therefore not affected by vibration or movement. This makes
it suitable for offshore and similar installations.

Non-Depleting Technology

The non-depleting sensor technology means that there
is no regular replacement of cells, thus greatly reducing
maintenance time and the cost of ownership. The cell
performance is consistent and does not drift as it is not
consumed by the process.

Easy Installation with Local Display

The XTC601 binary gas analyzer provides two 4-20 mA
outputs and is housed in a robust and weather-proof
casing, allowing the analyzer to be placed at the point of
measurement.

The closer the analyzer can be installed to the sample point,
the better, for many reasons. These include, faster overall
speed of response (for safety), less sample line or cabling
(saves cost) greater choice of installation points (flexibility).
Also having a local display does not require two operators (or

walking back and forth to the control room) for maintenance
or diagnostics.

External Sensor Input

The unit has the facility to accept a 4-20 mA signal from an
external source such as dew point sensor, temperature probe
or user-defined sensor, and display it on the screen. This
saves the cost of buying and installing an external display
for another parameter that only requires occasional visual
inspection.

Technology

Thermal Conductivity Sensor

Thermal conductivity (TC) is a property of all gases. This
can be exploited as each gas has a different TC value and is
used to determine the level of one gas in a binary or pseudo­binary mix. Air is a good example of a pseudo binary mix as it
has a fixed proportion of oxygen and nitrogen (both with very
similar thermal conductivities). The analyzer can be supplied
with a fixed or flowing reference.

The XTC601 binary gas analyzer utlizes thermal conductivity
technology to accurately measure one of the two gases
present in the sample. The instrument is very stable which
gives the user confidence in the measurement. This is
important in safety applications such as CO
monitoring.

Measurement Principle

The measuring principle is via matched thermistors in a
Wheatstone Bridge configuration. One thermistor is in the
sample cell and the other is either in a sealed (or flowing)
reference chamber. The whole assembly is heated to +50°C
to ensure an iso-thermal environment. This provides an
accurate and stable platform for measuring the target gas
concentration.

membrane

2/H2

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