The World’s Only Portable Clamp-On Steam Meters: FLUXUS G601 ST and G608 ST

FLEXIM has been setting standards for 30 years, and with FLUXUS ST portable ultrasonic steam flow meters, boundaries for non-invasive measuring technology have been pushed again.

Non-invasive and efficient

FLUXUS ST measures steam flow non-invasively from the outside of the pipe. Non-invasive steam flow measurement means measuring without any interruption of operation and supply. Since clamp-on ultrasonic transducers are simply mounted on the outside of the pipe, installation requires just minimal effort and no opening of the pipeline.

The acoustic measuring method proves to be impressive with its exceptionally high measuring dynamics, high sensitivity at very low flow velocities and independence to flow direction. Due to this large flow range (flow velocities from 0.01 m/s up to 60 m/s), there is no need to reduce pipe diameter to fit an inline meter’s requirement of minimum flow velocity. Moreover, the non-invasive measurement does not cause any pressure loss. The transducer mounts can be completely insulated to reduce any heat loss to the environment.

With FLUXUS ST portable steam flow meters, for the first time ever, it is possible to capture all steam usage from very low to very high flow rates with one meter size.

Completely maintenance-free

Non-invasive steam flow measurement also means measuring without direct contact with the medium flowing in the pipe. FLUXUS ST has no moving parts. Therefore, FLUXUS ST is not subject to wear and tear and does not require any maintenance.

FLUXUS ST measures volume and mass flow of saturated and super­heated steam at temperatures up to 180 °C. The clamp-on ultrasound system is available as both a portable and a fixed-installation meter.

High-End Multifunctional Measuring Tool

The FLUXUS G601 ST is the new state-of-the-art portable Flow and Energy meter for all Flow and Energy applications found within the industry.

With the FLUXUS G608 ST, all these applications can be covered in hazardous areas. With an ATEX /IECEx Zone 2 certified transmitter and Zone 1 or Zone 2 certified transducers, portable metering is much safer with less effort.

In addition to non-invasive steam measurement, the FLUXUS G601 ST / G608 ST is also the meter of choice for measuring liquid flow, gas and compressed air flow, as well as energy flow in heating or cooling applications. All combined within one transmitter.

This makes the FLUXUS G601 ST the perfect tool for Energy Management and Maintenance, since only one measuring system is needed to handle all flow applications.

100% process availability is guaranteed when using a FLEXIM solution – the installation of a FLUXUS G601 ST does not disturb the steam process itself at any time.


  • Reliable and non-invasive steam measurement
  • Multi-functional – Measuring of liquids, gas, compressed air, thermal energy and steam flow.
  • The ideal measuring device for complete energy efficiency tasks (e.g. according to ISO 50001)
  • Non-invasive measurement for precise bidirectional, highly dynamic compressed air, gas, liquid and thermal energy flow rates
  • Portable, easy-to-use flow transmitter with 2 flow channels, multiple inputs/outputs and an integrated data logger with a serial interface 
  • Automatic loading of calibration data and transducer detection reducing set-up times and providing precise, long-term stable results
  • Li-Ion battery providing up to 25 hours of autonomous measurement operation
  • Proven clamp-on technology, transducers resistant to dust and humidity
  • Probe for wall thickness measurement available


Industry Applications

Technical Facts

Measurement uncertainty of the measuring system (volumetric flow rate)
Measurement uncertainty at the measuring point (volumetric flow rate)

±0.15% of reading, ±0.015 ft/s
Flow channels
saturated steam, superheated steam, liquids and gases, see technical specification for details
Process temperature
max. 356 °F
Process pressure
min. 44 PSIA
Pipe diameter range
1,80 inch to 39,40 inch
Flow velocity range
0.03 ft/s … 200 ft/s (depending on pipe size and transducer)
Explosion protection
Communication Protocol
Modbus RTU optional
Additional Information
please have your specific application tested for feasibility