Introduction: Quid Cross-Duct Ultrasonic Flowmeteres? 2. Quomodo Cross-Duct Ultrasonic Flowmeteres opus? 2.1 Transducer Elementes 2.2 Tempus Principli 2.3 Doppler Principle 3. Claves Compones Cross-Duct Ultra. Volum 3.1 Transducers 3.2 Signal Processor 3.3 Display et output 4. Advantae Cross-Duct Ultrasonic Flo. wmeters 4.1 n