Portable Doppler Flowmeter

The MainFLO flowmeter is designed for flow measurements in open channels under open surface flow conditions.

It is based on the DVP submerged Doppler velocity sensor and exploits its advanced signal processing capabilities.

The portable version of MainFLO is adapted to the needs of measurement campaigns thanks to its autonomous battery operation.

For permanent installations, the MainFLO is available with a central unit that can be connected to a power supply (MainFLO 'Fixed').


Flow measurements in open channels:

  • Sewerage and stormwater networks for permanent measurements or diagnostic campaigns, infiltration or capacity studies
  • Water treatment plant inlet/outlet
  • Tracking and recording of spills
  • Irrigation channels
  • Rivers for flood monitoring and flood prevention
  • Verification of existing flowmeters

Main benefits

  • Integrates algorithms to evaluate the quality of the measurement
  • Measurement of low water levels (15 to 20 millimeters above the DVP sensor)
  • Automatically switches to the flow calculation mode using height/flow tables, when the water level is too low, or the quality of the Doppler measurement is poor.
  • Large velocity range (bi-directional): +/- 1 cm/sec to +/- 5 m/sec
  • Suitable for measuring infiltrations, through its signal quality on low velocities.
  • Stationary (powered) and portable (battery-powered) versions
  • Bluetooth wireless communication
  • Rich operating software (MainFLO, WinFluid)
  • 2-year warranty, extendable to 3 years


  • Bidirectional velocity measurement by immersed Doppler technology
  • Height measurement by immersed piezometric sensor; optional use of a non-contact ultrasonic sensor on the Fixed version
  • Atmospheric pressure compensation box (Portable version)
  • Piezometric sensor: 0-150 mBar or 0-350 mBar; other ranges available
  • Spectral analysis of the velocity distribution for the calculation of the mean velocity on the wetted surface
  • Velocity accuracy: ± 2% of the read value for V ≥0.5m/s; ± 0.01 m/s for V<0.5m/s
  • Accuracy of the piezo height sensor: 0.1% PE
  • Flow Calculation:
    — by area/velocity table
    — by height/flow table, when the quality of the velocity signal or the water level is too low
  • LCD display for real-time measurement monitoring
  • Data logger function:
    — Files of time-stamped measurements: Velocity, Level, Flow, Signal quality, Temperature, Speed of Sound
    — Capacity: 4 GB of non-volatile memory (ex: 200 days of data every 2 minutes)
  • IP67 sealing level
  • Operating temperature: -20 to +60°C
  • USB/RS232 and Bluetooth communication
  • Available in Ex certified version (Class I / Zone 1)


  • Power Supply:
    — 7 Ah rechargeable lead acid battery (12 Ah optional); 6 months autonomy for a measurement every 2 minutes.
    — external power supply 9-28 VDC
  • Outputs: 2 count/alarm contact outputs
  • Material: Polypropylene copolymer resin
  • Dimensions: 124mm 246mm 270mm
  • Weight: 5 kg


  • Power supply: 10-28 VDC
  • Outputs: 2 count/alarm contact outputs and 4 4-20mA outputs (flow, velocity, height, etc.)
  • Material: Aluminium
  • Dimensions: 82mm 150mm 222mm
  • Weight: 2.5 kg

Related products

  • Installation accessories in stainless steel 316: Sensor support plates and straps adjustable by spacers
  • Output connection cables with waterproof connectors
  • Hydreka's operating software (MainFLO, WinFluid), allows in particular the generation of standard profiles (circular, rectangular, ovoid ...) or any other profiles.
  • Velocimeters and profilers


MainFLO fixed
MainFLO cerclage
MainFLO different set-ups
MainFLO- Conversion screen
MainFLO screen
MainFLO cerclage inox, installation
MainFLO cerclage inox, installation
MainFLO, on the field
MainFLO, on the field
MainFLO, on the field
MainFLO, on the field
MainFLO, on the field
MainFLO, on the field