FLUXUS® F704 - The ultrasonic flow meter for permanent installation

The FLUXUS® F704 is FLEXIM's flow meter for permanent installation in nearly any liquid flow metering application - especially in the industrial environment. Its non-intrusive measurement technology ensures a precise bi-directional, highly dynamic flow measurement over a wide turndown ratio.

Enclosed in a robust metal field housing, the F704 flow meter is completely water-tight and designed for usage in rough environments. As the transducers are mounted on the outside of the pipe wall in rugged VARIOFIX mounting fixtures, the system does not suffer from wear and tear or clogging, can't be a risk for leaks and will not cause any pressure drops inside the pipe. Process interruptions or even production stops are a thing of the past with the F704.

Due to its matched and paired transducers as well as the internal temperature compensation (compliant to ANSI/ASME regulations), the measurement system is drift free and zero stable ensuring accurate readings. Moreover, as the transducer calibration data is automatically loaded by connecting the transducer to the transmitter the set-up times are significantly reduced. As of its exceptional dual-uP technology, the high number of measuring cycles per second and the adaptive signal processing, the FLUXUS® F704 flow meter produces stable and reliable measuring results even under the most difficult conditions.


The F704 flow meter is the ideal instrument for monitoring chemically aggressive, toxic or just media that you want to keep inside the pipe.

The liquid flow meter can be applied at inner pipe diameters ranging from 6 mm up to 12 m (no limitations on pipe wall thickness or material) and media temperatures from -40°C up to 200°C (-170° up to 600°C with the WaveInjector mounting fixture). The measurement is pressure independent and can take place on pipes of almost any material and on almost any liquid.

With up to two measurement channels, the FLUXUS F704 permanent liquid flow meter can be applied to difficult measurement points where other meters fail and is completely unaffected by viscosity, composition and toxicity of the medium itself as well as dust and humidity on the pipe wall outside. Due to innovative Hybrid trek Mode implemented in the flow computer, also liquids containing a high content of solid particles or gaseous loads can accurately be metered.

Further, with its wide range of electrical inputs and outputs, the FLUXUS F704 flow meter can handle a variety of process parameters within liquid flow metering applications. Input quantities such as temperature and/or pressure can be used by the flow meter, together with the measured flow, for the calculation of further quantities like thermal energy / BTU, mass flow rate, density, etc.

The FLUXUS F704 flow meter is also available in an ATEX / IECEx Zone 2 / FM Class I, Div. 2 approved version, allowing its usage in the respective hazardous areas. FLEXIM also offers liquid flow meters for usage in ATEX Zone 1 environments, such as the FLUXUS F800 and FLUXUS F801 (for Offshore usage).




  • Non-intrusive - Installation without process interruption or production stop

  • Virtually maintenance free due to permanent coupling pads and and rugged mounting fixtures

  • Low installation and operation costs (independent of pipe pressure and size)

  • Highly accurate, reliable and stable measuring results even under difficult conditions

  • Versatile electrical inputs and outputs for the optimal adaptation to the individual application needs

  • Ideal solution for the measurement of aggressive, corrosive or toxic media in hazardous areas ( FM Class I, Div. II / ATEX / IECEx Zone 2 version available)

  • Exhaustive internal database with complete parameter set of a variety pipe materials and media

  • Ideal solution for permanent thermal energy / BTU metering

  • Volumetric and mass flow measurement at up to 600°C hot pipes by using the patented WaveInjector Solution 


Chemical industry

  • Measurement of nearly any liquid
    • corrosive or toxic media (acids, bases)
    • non-conductive media
    • highly viscous media
    • media containing fibers or solid particles, long-chained polymers and much more
  • Measurement of high temperature liquids, such as heat transfer media (water/glycol at 250°C) and thermal oils (up to 400°C) or molten salts (up to 600 °C)

Petrochemical industry

  • Measurement of basic materials as well as intermediate and final products
  • Measuring at high temperatures, for example tar, bitumen, quench liquids

Power plants

  • Measurement of the cooling water, boiler feed water, condensate and heat circuits
  • Measurement of fuel lines
  • Measurement of reservoir water lines and large tubes for hydroelectric plants

Oil and Gas

  • Measurement of all hydrocarbon liquids, on high pressure systems and high temperatures (Upstream, Midstream and Downstream)

Facility management / Energy Metering - BTU

  • Monitoring and optimization of heating and air conditioning systems in large building complexes
  • Pump control

Pharmaceutical and semiconductor industry

  • Measurement of ultra pure fluids, even in PVC, PFA and glass pipes

Food and beverage industry

  • Hygienic contact-free measurement of liquids
  • Thermal energy measurement in the energy supply of central boilers and sanitizing machines

Water and Wastewater industry

  • Flow measurement on large diameter pipes (influent, effluent, sludges)
  • Consumption and distribution measurements
  • Measurement on underground pipelines - IP68 transducers are buried in the ground
  • Chemical flows (small pipe and low flows)

Mechanical engineering and plant engineering

  • Leak detection on hydraulic systems
  • Measurement of cooling lubricant
  • Monitoring of heat and cooling circuits and of pumps


Technical Facts

FLUXUS® F704: liquid flow meter for permanent installations
Flow channels 1 or 2
Operating temperature range of transmitter -10°C ... 60°C
Degree of protection (acc. EN60529) IP65
Functional Safety (acc. to IEC / DIN EN 61508) SIL2
Available Hazardous Area Classification (optional) ATEX and  IECEx Zone 2 or FM Class I, Div. 2
Outputs A variety of combinations are available from the following:
current (0/4 mA ... 20 mA), voltage, frequency, pulse, alarm
Inputs Maximum 4, Available are: Temperature (PT 100 4-wire), current, voltage
Communication Protocol HART or Foundation Fieldbus or ModBus RTU or RS485 or BACNet
Media temperature -40°C ... 200°C (-170°C ... 600°C with High Temperature WaveInjector mounting fixture)
Pipe diameter range 6 mm ... 12.000 mm
Flow velocity range 0,01 ... 25 m/s
Measurement accuracy ±1.6 % of reading, ±0.01 m/s (standard)
±1.2 % of reading, ±0.01 m/s (extended calibration)
±0.5 % of reading, ±0.01 m/s (field calibrated)
Repeatability ±0.15% of reading, ±0,01 m/s



Technical Specification FLUXUS F70x
application/pdf, English, 1.04 MB
Brochure FLUXUS® Liquid
application/pdf, English, 2.19 MB