Non-invasive compressed air flow measurement - FLUXUS G721 CA

Compressed air is a very expensive form of energy. This is due to its efficiency: for every joule of mechanical work which is done with a pneumatic tool, approximately twenty times the amount of electrical energy must be spent. However, despite this poor yield, compressed air is practically indispensable in many industries because of its production-related advantages. This makes it all the more important to use the valuable medium as efficiently as possible.

Measurement creates Transparency

If you want to avoid waste it's necessary to measure. Through the precise detection of the current volume flow, components of a system can be dimensioned in a particularly cost-effective manner through the fast and unmistaken identification of possible overloads (such as when air velocities are too high) or malfunctions in the network. The exact assignment of consumption proportions to individual production stages also offers possibilities for fact-based, economic decisions. Moreover, the volume-flow measurement indicates the amount of compressed air lost as a result of leaks – an important economic factor, as every third compressor is operated only to compensate for air losses.

But how do you best measure compressed air flows? Non-invasively, of course!

The  FLUXUS G721 CA compressed air flow meter is thus the ideal solution. FLEXIM’s non-invasive clamp-on ultrasonic technology is unique in that it can be applied to measure compressed air flow rates even at very low pressures (down to 3bar on steel lines and atmospheric pressure on plastic lines). Also even the lowest flow rates are accurately captures revealing the slightest flow rates from the smallest leaks where there should be none.

For this reason, the FLUXUS G721 CA is particularly suitable for non-invasively measuring quantities drawn off at individual points in the compressed air grid as well as detecting leaks within it. Due to being non-invasive by principle, the FLUXUS G721 CA can never be a potential source of leaks by itself.


  • Reliable and maintenance-free compressed air flow measurement from the pipe wall outside (starting at 45 psi on steel pipes; atmospheric pressure and below at plastic pipes)
  • Highly accurate due to paired, temperature compensating and traceable calibrated ultrasonic transducers
  • Extremely high measuring dynamics from the lowest to the highest flow velocities
  • Simple, cost-effective retrofitting without any disruption to supply and pipe works
  • No risk of leakage, No pressure losses
  • Bidirectional measurement: simple recognition of the flow direction
  • Ready for Advanced Meter Verification


Industry Applications

Technical Facts

Measurement uncertainty of the measuring system (volumetric flow rate)
Measurement uncertainty at the measuring point (volumetric flow rate)
±1…3 % of reading ±0.005 m/s
0.15 % of reading ±0.005 m/s
Flow velocity range
0.01...35 m/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
15mm ... 250mm
for temperature range
-40°C ... +170°C
4-20mA active/passive
4-20mA HART active/passive
4-20mA active/passive
Digital communication
Modbus RTU/TCP
Profibus PA
Foundation Fieldbus
Advanced Meter Verification (AMV)
Additional Information
For more detailed Information please download the Technical Specifications