Technical Characteristics and Environmental Resilience
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Time-of-Flight Principle: The sensor emits ultrasonic pulses that reflect off the product surface. The distance is calculated based on the time it takes for the pulse to return. To ensure precision, the FDU90 features an integrated temperature sensor that automatically corrects the Time-of-Flight for changes in air temperature.
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Chemical and Weather Resistance: The sensor is hermetically welded and constructed from PVDF, providing excellent chemical resistance. With an IP 68 rating, the FDU90 is both weather-resistant and flood-proof, making it suitable for outdoor installation and wastewater applications.
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Self-Cleaning Effect: The vibrating membrane of the ultrasonic sensor naturally resists the formation of build-up. This self-cleaning property ensures consistent signal quality even when measuring dusty solids or steaming liquids.
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Flexible Installation: The sensor is installed separately from the transmitter (FMU90/FMU95), with cable distances possible up to 300 meters. This allows the electronics to be located in a safe, accessible area while the sensor operates in rough ambient conditions or hazardous zones.
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Minimal Blocking Distance: With a very small blocking distance of only 0.07 m (0.23 ft), the FDU90 is optimized for measurements in small tanks or channels where the liquid level may rise very close to the sensor.
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Optional Integrated Heating: To prevent the formation of ice on the sensor membrane in cold climates, an optional integrated heater is available, ensuring reliable measurement year-round.
Technical Specification Matrix
| Feature | Technical Details |
| Measuring Principle | Ultrasonic (Non-contact) |
| Max. Range (Liquids) | 3 m (9.8 ft) |
| Max. Range (Solids) | 1.2 m (3.9 ft) |
| Blocking Distance | 0.07 m (0.23 ft) |
| Process Temperature | -40 to +80 °C (-40 to +176 °F) |
| Process Pressure | 0.7 to 4 bar (10 to 58 psi) |
| Sensor Material | PVDF (Hermetically welded) |
| Degree of Protection | IP 68 |
Primary Applications
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Open Channel Flow Measurement: Monitoring water flow in flumes and weirs for environmental or industrial discharge applications.
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Liquid Level in Small Tanks: Level monitoring in chemical storage, wastewater sumps, and buffer tanks with low ceilings.
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Bulk Solids on Conveyor Belts: Measuring the profile or presence of coarse materials on belts, in crushers, or at stockpiles.
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Wastewater Treatment: Reliable level detection in grit chambers and sludge settling tanks where high humidity and aggressive gases are present.
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Hazardous Area Monitoring: Certified for use in explosion-hazardous areas where combustible gases or dusts may occur.
