Endress+Hauser Prosonic S FDU90 ultrasonic sensor

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The Prosonic S FDU90 ultrasonic sensor is designed for continuous, non-contact level and flow measurement and has a 70 mm blocking distance. The small blocking distance allows the FDU90 to maximise filling capacity in short-range applications.

The blocking distance of an ultrasonic sensor is the distance measured from the sensor face, in which true level echoes cannot be distinguished from the transient characteristics of the sensor. When fill levels extend into the sensor’s blocking distance, accurate evaluation of the ultrasonic signals cannot be derived. This makes minimising blocking distances crucial to maximise filling capacity. In low-range applications, capacity gains of between 8% and 25% can be attained by the FDU90. In case of accidental flooding, the sensor’s IP68 protection and optional anti-flooding tube (air-trap) guarantees reliable measurement.

The FDU90 measures the level of liquids, pastes, sludges and powder to coarse bulk materials. The sensor is also used for flow measurement in open channels and measuring weirs. It is suited to harsh ambient conditions and can be connected up to 300 m from the signal transmitter. Operating pressure range is 0.7 to 4 bar, and temperature range is -40 to +80°C, with integrated temperature compensation.

Initially developed for the water/wastewater industries, the chemically resistant PVDF material of the FDU90 makes it suitable for chemical storage applications. Storage tanks can be filled up to the 70 mm blocking distance so fewer chemical deliveries are required. Other applications include sewerage tunnels, dosing tanks and conveyer belts.