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The non- intrusive ultrasonic gas flow meter for operation in hazardous areas

The FLUXUS G809 is FLEXIM's dual channel ultrasonic clamp-on flow meter for bi-directional flow measurement of gases in hazardous areas ATEX, IECEx Zone 1.

The FLUXUS G809 series is perfectly suited for demanding industrial and process applications. With its flameproof housing, compact design, and the corrosion resistant ATEX, IECEx Zone 1 – FM Class 1. Div. 1 rated transducers mounted in “fit for purpose” rugged mounting fixtures, the system’s mechanical stability and permanent contact with the pipe surface is assured.

The FLUXUS G809 gas flow meter allows for inherently bi-directional gas flow measurement of operational (gross) volumetric flowrate. Standard (net) volume flow can also be provided at a user-entered fixed temperature/pressure. The FLUXUS G809’s two measurement channels make the device perfectly suited for difficult measurement points, and it is completely unaffected by gas density, viscosity and composition as well as temperature and pressure.  Even in wet gas applications with up to 5% Liquid Volume Fractions, the G809 gas flow meter is applicable and accurate. The non-intrusive design of the G809 flow meter means the transducers are mounted on the outside of the pipe wall. This way the system does not suffer from wear and tear or clogging and creates no risk for leaks or pressure drops inside the pipe.

Due to its matched and paired transducers as well as internal temperature compensation (compliant to ANSI/ASME), the measurement system is drift free and zero stable ensuring accurate readings. The gas flow meter can be applied on inner pipe diameters ranging from 0.4 inch up to 83 inches (with no limitations on pipe wall thickness or material) and media temperatures from -40 °F up to 210 °F.


  • ATEX / IECEx Zone 1FM Class I, Div. 1 approvals
  • Bi-directional flow measurement of liquids and gases
  • Cost effective: No pipe work, no process shut-down, maintenance-free
  • Zero-point stable and drift free - Carefully matched and temperature compensated transducers (fully ANSI / ASME compliant)
  • Retrofittable - No pipe modification required, no process shut-downs
  • Maintenance Free - Free of wear & tear and abrasion, not prone to clogging or corrosion, no fugitive emissions
  • High tolerance to entrained solids and gas wetness
  • Independent of pipe size, material, operating pressure, and gas composition
  • Flexible configurable outputs


Industry Applications

Technical Facts

Measurement uncertainty at the measuring point (volumetric flow rate)
± 1...3 % of reading ±0.02 ft/s
Measurement uncertainty of the measuring system (volumetric flow rate)
0.15 % of reading ±0.02 ft/s
Flow velocity range
0.03.. 115 ft/s, depending on pipe diameter
Ex zone transmitter
FM Class I - Div1
Power supply
100-230VAC, 24DC
Available transducers
Shear wave/Lamb wave
for Ex zones
FM Class I - Div1
for pipe sizes range
0.28 inch to 63 inch
for temperature range
-40°F to +392°F
4-20mA active/passive
4-20mA HART active/passive
4-20mA passive intrinsic safety
Digital communication
Modbus RTU
Additional Information
For more detailed Information please download the Technical Specifications