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Ultrasonic measurement
Prosonic FDU91F

Hygienic sensor for level and flow measurement for connection to FMU9x (measuring range up to 10m)

  • Prosonic FDU91F ©Endress+Hauser
  • Prosonic FDU91F ©Endress+Hauser
  • Time-of-Flight measuring principle

The FDU91F ultrasonic sensor for continuous, non-contact and maintenance-free level measurement of fluids, pastes, sludges and powdery to coarse bulk materials. Also for flow measurement in open channels and at weirs. Measurement is unaffected by dielectric constant, density or humidity and also unaffected by build-up due to the self-cleaning effect of sensors. Fully welded 316L with hygienic process connection available. Maximum measuring range in liquids 10m (33ft), solids 5m (16ft).


  • Integrated temperature sensor for Time-of-Flight correction. Accurate measurements are possible, even if temperature changes are present

  • Hermetically welded sensors (316L, 1.4404, 1.4435) for highest chemical resistance

  • Suited for rough ambient conditions thanks to separate installation from the transmitter
    (up to 300m)

  • Reduced build-up formation because of the self-cleaning effect

  • Integrated automatic sensor detection for transmitters FMU90/FMU95 for simple commissioning

  • Weather resistant and flood-proof (IP 68)

  • Hygienic process connections available

Field of application

Continuous, non-contact level measurement of fluids and bulk materials in silos, on belts, stockpiles or in crushers. Also for flow measurement in open channels and at weirs. Used in measurements in low structural heights.

  • Process connections: Thread, Tri-Clamp

  • Temperature: -40 to +105°C (-40 to +221°F)

  • Pressure: 0.7 to 4bar (10 to 58psi)

  • Max. measuring range: Liquids 10m (33ft), solids 5m (16ft)

  • Blocking distance: 0.3m (1ft)

  • International explosion protection certificates, hygienic certificates

Documents / Manuals / Software

Accessories / Spare parts

Predecessor / Successor

Predecessor: Prosonic FDU80F, Prosonic FDU81F, FMU801


Endress+Hauser AG
Kägenstrasse 2 4153 Reinach BL Switzerland
Tel.: +41 61 715 7700
Fax: +41 61 715 2888
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