Key Specifications
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Accuracy
± 2 mm + 0.17% of measured distance
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Operating Temperature
-40 °C … 80 °C
(-40 °F … 176 °F) -
Operating Pressure / Overpressure Limit
0.7 bar … 4 bar abs
(10 psi … 58 psi) -
Maximum Measuring Range
Liquids: 10 m (33 ft),
Solids: 5 m (16 ft) -
Wetted Parts
PVDF (fully sealed housing IP68 / NEMA6P)
Applications
The FDU91 ultrasonic sensor provides continuous non-contact level measurement for liquids, pastes, slurries, and bulk materials of various particle sizes. It’s also used for flow measurement in open channels and weirs. Measurement accuracy remains unaffected by dielectric constant, density, or moisture content. The self-cleaning feature prevents buildup of deposits. Suitable for hazardous areas, with maximum measuring ranges of 10 m (33 ft) for liquids and 5 m (16 ft) for solids.
This sensor enables continuous non-contact level monitoring of liquids and bulk materials in silos, conveyors, stockpiles, and crushers, as well as flow measurement in open channels and weirs. Particularly effective in confined space applications.
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Process connection: Threaded
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Temperature range: -40 to +80°C (-40 to +176°F)
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Pressure range: +0.7 to +4 bar (+10 to +58 psi)
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Maximum measuring range: Liquids 10 m (33 ft), Solids 5 m (16 ft)
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Dead zone: 0.3 m (1 ft)
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International explosion protection certifications
Key Benefits
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Integrated temperature sensor for time-of-flight compensation ensures accurate measurements despite temperature fluctuations
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Hermetically welded PVDF sensor with excellent chemical resistance
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Ideal for harsh environments with remote transmitter mounting capability (up to 300 m)
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Minimal deposit buildup thanks to self-cleaning effect
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Automatic sensor identification simplifies commissioning with FMU90/FMU95 transmitters
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Weatherproof and submersible (IP 68 rated)
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Optional built-in heater prevents sensor icing for reliable measurements



