Do you need to measure very low flows? Look no further, the FLUXUS F721XLF low flow flow meter is the solution you need!

FLUXUS F721XLF is FLEXIM’s non-intrusive metering system for the reproducible and long term reliable measurement of extremely low flow liquid rates down to 1 gal/h and below on line sizes ranging from 0.4 inch to 2 inches independent of the pipe wall thickness and pressure ranges. The FLUXUS F721XLF low flow rate meter is available both in aluminum and stainless-steel housing with ATEX/IECEx zone 1/2, FM Class I Div. ½ certifications.

This low flow ultrasonic flow meter offers advanced data processing capabilities, sophisticated signal filters, bidirectional communication protocols and in-house system factory calibration to achieve highly accurate and repeatable measurements of extremely low flows.

FLEXIM is the much more cost-effective and safer alternative for measuring extremely low flows of any liquid

In comparison to wetted instrumentation, these low flow sensors do not suffer from mechanical stress or wear and tear by the medium and are thus not only much more cost efficient, but also offer significantly higher operational safety as the risk of leaks can completely be eliminated.

These low flow liquid flow meters offer high accuracy and repeatability at extremely low flow velocities. This is achieved with carefully matched and temperature compensated transducers (acc. to ANSI/ASME MFC 5.1-2011), highly sensitive electronics and sophisticated internal signal processing as well as a highly precise and traceable wet flow calibration (according to NIST standards) at FLEXIM‘s low flow calibration facility.


  • No process shutdowns or interruption of supply
  • No potential for leaks
  • Completely maintenance free
  • Accurate and highly repeatable low flow measurement
  • Applicable to any pipe and any liquid media
  • Rugged and hazardous area approved transducers and transmitters (ATEX / IECEx Zone 1/2, FM Class I, Div. 1/2)
  • Matched transducers, advanced digital signal processing (DSP) and efficient algorithms ensure stable measurements at very low flows
  • AMV Logo


Industry Applications

Technical Facts

Measurement uncertainty of the measuring system (volumetric flow rate)
±0,3 % of reading ±0.0006 m/s
Measurement uncertainty at the measuring point (volumetric flow rate)
±1,0 % of reading ±0.0006 m/s
Flow channels
Operating temperature of the transmitter
-40 °C ... +60 °C
Degree of protection
IP 65/66
Optional hazardous area classification
FM Class I, Div. 1/ 2 or ATEX / IECEx Zone 1 / 2
A variety of combinations are available from the following: current (0/4 mA ... 20 mA), voltage, frequency, pulse, alarm
Maximum 4, Available are: Temperature (PT 100 4-wire), current, voltage
Digital communication
Modbus RTU/TCP
Profibus PA
Foundation Fieldbus
Media temperature
-40 °C ... +200 °C
Pipe diameter range
10 mm ... 50 mm (independent of material and wall thickness)
Flow velocity range
> 0,003 m/sec (at stable media temperatures flows as low as 0,001 m/sec can accurately be monitored)
Calibrated accuracy
±1 % MV ±0.001 m/s
Advanced Meter Verification (AMV)