Flow Meters for Fluid

Fuji Electric delivers high performance ultrasonic Flow Meters to optimized for 0.5-inch to 234-inch pipe diameters. The portable ultrasonic flow meter is ideal for flow surveys, verifications, and energy/BTU measurements. The fixed unit offers high performance measurement in a versatile and easy to setup package. The Duosonics model is a hybrid pulse doppler-transit time unit for irregular profiles, non-Newtonian flows, and applications lacking sufficient upstream/downstream straight run mounting requirements.

Measurement principle – Transit time difference method

pair of sensors are installed on the outside wall of the pipe, facing each other slantingly.  Ultrasonic waves are propagated diagonally between the upstream and downstream sensors.
In one case, the wave is “carried” by the fluid, in the other it is “braked”. It therefore takes a different time to switch from one sensor to another. This difference is proportional to the measurement principle of ultrasonic flowmeters for liquid speed and therefore to the flow rate of the fluid.

transit time difference method

Anti-bubble measurement (ABM) system

The 32 bits  microprocessor based electronics allows a high accuracy (±1%), a response time of 1 second or less, a very good immunity to air bubbles (ABM system) and to change of fluid pressure and temperature (continuous calculation of sonic speed).

signal averaging

Flange mounted FST flowmeter – High accurate measurement

Three pairs of sensors offer an accuracy of ± 0.2%.  . The FST model is suitable for all energy-saving applications where its high precision and the absence of pressure loss help to reduce consumption and costs.
The FST measurement principle is the transit time difference method with parallel three measuring paths.

Transit time difference method with parallel three measuring paths


  • Water supply and sewage systems  : leakage investigation of water pipe and investigation of the flow direction in the water distribution pipe
  • Thermal or electric power plants : flow rate measurement of the boiler water supply, condenser circulating pump and turbine oil
  • Heating/cooling systems : flow rate measurement of hot water and chilled water in heating and cooling
  • Stations thermales : water extracted quantity measurement
  • Food manufacturing plant : flow rate measurement of raw material and washing water
  • Other industries : flow measurement of all homogeneous liquids capable of ultrasonic wave propagation (service water, sewage, industrial water, seawater, pure water, water for irrigation, oil etc.)
Models débitmètre FST débitmètre M-flow Débitmètre time Delta-C Débitmètre time delta-C étendu FSC PORTAFLOW-C
Mounting method Flanges Clamp-on outside the pipe
Clean liquid with no air bubbles ++ ++ ++ ++ ++
Sewage, drainage + + + + +
Viscous liquids + + + + +
Oil + + + + +
Corrosive liquids + ++ ++ ++ ++
Non-conductive liquids ++ ++ ++ ++ ++
Low-velocity fluids na + + + +
Pulsating fluids na (1) (1) (1) (1)
High-temperature fluid + + + + +
High-pressure fluids + ++ ++ ++ ++
Protection IP66 IP65 IP66 (IP67 option) IP67 IP64
Flange mounted DN50, DN80, DN100 mm na na na na
Clamp-on detectors na  FSSA detector
25 to 225 mm (outside diameter) / -40 to +100°c
Capteur FSSA
na FSSC detector
50 to 1200 mm (outside diameter) / -20 to +120°c
Capteur FSSC
na FSSD detector
13 to 300 mm (outside diameter) / -40 to +100°c
Capteur FSSD
na FSSE detector
200 to 6000 mm (outside diameter) / -40 to +80°c
Capteur FSSE
na FSSH detector
50 to 400 mm (outside diameter) / -40 to +200°c
Capteur FSSH
Pressure max PN40 No limit
Fluid temperature -40°C to +150°C Depending on the detector used
Flow velocity 0 to ±0.3…10 m/s 0 to ±0.3…10 m/s 0 to ±0.3…32 m/s
Accuracy ±0.2 % ±1.5 % ±1.0%
Depending on diameter and velocity
Power supply voltage 100-240 V AC 50/60 Hz 100-240 V AC 50/60 Hz ou 20-30 Vcc 100-240 V Ac 50/60 Hz 12 hours battery
12 V Ac ou 100-240 V AC

na : Not applicable
(1) : Suitable under conditions
+ : Suitable
++ : Best suitable

Ultrasonic Flowmeter Detector (FSS Series)

Ultrasonic Flowmeter TIME DELTA-C (FSV/FSD Series)

Ultrasonic Flowmeter TIME DELTA-C Advanced Type (FSV Series)

Ultrasonic Flowmeter Detector (FSG Series)