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. The analyzer can be supplied explosion-proof and suitable for hazardous areas.

Product Features

  • Suitable for use in ATEX, IECEx, TC TR Ex & CCSAUS certified Hazardous Areas
  • Optional status LED’s 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%, 0-1% for H2 or He
  • Stability ±0.5% per month (of span)

Technical Specifications

Measurement TechnologyThermal Conductivity sensor
Measured GasesAir, Ar, CH4, CO2, H2, He or N2 (more available on request)
Gas RequirementsNon-condensing sample with particles ±3μm
Measurement RangeSelectable from 0-5 up to 0-100%
50-100% up to 99-100%
Measurement Range (H2 & He)Selectable from 0-1% up to 0-100%
50-100% up to 99-100%*
Display Resolution0.1%
Display TypeBacklit LCD
Intrinsic Error (Accuracy)< ±2% of span**
Response Time (T90)Standard < 20 seconds**
Repeatability±0.2% of span
Linearity±1% span
Zero Stability±0.5% of span per month
Span Stability±0.5% of span per month
Sample Flow Rate100 to 500 ml/min (0.2 to 1.27 scfh)
Sample Flow Rate(Ex)270 to 330 ml/min (0.54 to 0.66 scfh))
Sample Flow Effect
(calibrated at 300 ml/min)
< 1% of span for flows:
100 to 500 ml/min
Sample PressureAnalyzers are callibrated at atmospheric pressure and must be operated with an atmospheric vent, unless otherwise stated
Maximum Safe Pressure4 barg (58 psig)
Sample Temperature5 to 45°C C (+32 to +104°F) max
Sample Cell Temperature+50°C (+122°F)
Electrical Specifications
Analog Inputs2 off 4-20 mA inputs
One for an external sensor that can be displayed on the screen
One to act as an active compensation for the process conditions
Analog Outputs2 off 4-20 mA outputs
Output RangesPrimary range is set to the calibrated range of the instrument
The second is user selectable
Alarms2 off single pole changeover (SPCO) relays (250 V, 5 A max)
DataloggingThe user can use the digital communications to log the output from the analyzer
The unit will store 40 alarm points and the min/max O2 concentrations with date and time stamp
Digital CommunicationsMODBUS RTU over RS485 Protocol
Power Supply24 V DC; 1.5 A max
Operating Conditions
Ambient Temperature0 to 40°C (32 to 104°F)
Mechanical Specifications
Warm Up Time< 25 minutes
Stabilization Time5 minutes
Dimensions172 x 234 x 234mm (h x w x d)
Wetted Materials316 stainless steel, boroscillicate glass, platinum, (plus O-ring)
O-Ring MaterialsViton, Silicone or Ekraz
Gas Connection1/4” NPT FEMALE GP models, 1/8” NPT FEMALE Ex & GP2 models
Ingress ProtectionIP66, NEMA 4X
Hazardous Area Classification
Ex d IIB +H2 T6 Gb
Ex tb IIIC T85°C Db IP66
IECExEx d IIB +H2 T6 Gb
Ex tb IIIC T85°C Db IP66
Temperature Ranges for ATEX and IECEx as per O-ring TypeSilicon: Ta = -40°C to +55°C
Viton: Ta = -15°C to +55°C
Ekraz: Ta = -10°C to +55°C
CCSAUSClass I, Division 1, Groups B,C,D T6
TC TR Ex-Cert1Exd IIB+H2 T6 Gb
*Ranges 80–100% up to 99–100% will require a flowing reference and selection of the 4-port model (for H2 and He only)
**The typical intrinsic error and response time will be as above.
Certain gas combinations and/or ranges may have different specifications.
Please consult Michell Instruments for specific cases.
For example, CO2 / N2 would be < 50 seconds for T90.
Note: If the 4-port version is selected then a reference gas with a flow rate of 300ml/min is required

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