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The FLEXIM FLUXUS G721 is a technological breakthrough in the ultrasonic clamp-on volume and mass flow measurement of gases.
With its state-of-the-art hardware design and powerful digital signal processing it surpasses any other non-intrusive ultrasonic gas flow meter in terms of accuracy, reliability and versatility.

Highly sophisticated signal filters, faster than ever processing capacities and advanced measurement algorithms make the FLUXUS G721 ultrasonic clamp-on gas flow meter the standard setting measuring solution for any industrial application - even for the most challenging ones. The meter adapts itself automatically to the respective measurement conditions and compensates for flow profile disturbances such as beam dispersal and structure-borne noise, allowing for even more precise and reliable measurements. Extreme fast measurement cycles enable precise real time monitoring of highly dynamic processes.

Standard Setting Clamp-on Flow Measurement

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FLUXUS® G721 Ultrasonic Flow Meter for Gas


Measurement uncertainty at the measuring point (volumetric flow rate)
± 1 - 3% of reading ±0.02 ft/s
0.15% of reading ±0.02 ft/s
Flow velocity range
0.03 to 115 ft/s, depending on pipe diameter
Ex zone transmitter
ATEX/IECEx Zone 2, FM Class I /Div 2
Power supply
100-230VAC, 24DC, 12DC
Available transducers
Shear Wave/Lamb wave
For Ex zones
ATEX/IECEx Zone 1/Zone 2, FM Class I - Div2
For pipe sizes range
0.28 inch to 63 inch
For temperature range
-40°F to +392°F / WI: -328°F to +1112°F
4-20mA active/passive, 4-20mA HART active/passive, pulse/frequency/binary
Pt100/Pt1000, 4-20mA active/passive, Binary input
Digital communication
Modbus RTU/TCP, BACnet MSTP/IP, Profibus PA, Foundation Fieldbus
Advanced Meter Verification (AMV)


  • No process interruption for installation, no pipe works - maintenance-free (no need for frequent work in hazardous areas)
  • Certified for operation within hazardous areas (FMc Class I, Div. 2, ATEX, IECEx Zone 2)
  • Fast measuring dynamics (output of measurement data every 10ms), capturing highly pulsating flows
  • Reliable measurements of wet gas (up to LVF of 5%)
  • High operational safety with no risk of leaks
  • Independent of pipe material, wall thickness and internal pressure
  • Accurate and repeatable measurement readings - even at extremely low flow rates (high turndown ratio)
  • Highly cost efficient in comparison to wetted instrumentation
  • Every measurement system is pre-calibrated in-house (traceable to national standards) and delivered with a calibration certificate
  • Matched transducers, integrated temperature compensation (according to ANSI/ASME MFC-5.1-2011 regulations) and digital signal processing guarantee a high zero point stability and drift free measurement readings
  • Permanent coupling with unique couplant pads, FlexSpring secured mounting fixtures guarantee durable contact pressure also on heavily vibrating pipes
  • Bidirectional communication as well as remote parameterisation and diagnostic capabilities
  • Enabling complete monitoring of processes as well as supervision and control of critical operations
  • Advanced Meter Verification
Interested in learning more? Contact us!
(732) 382-5000