The ultrasonic tubular transducer is activated at the centre thereof by two symmetrical electromechanical converters. The vibration generated by the two electromechanical converters is converted and then transmitted to the tube via a coupler. The ultrasonic transducer can be vibrationally isolated from the interfaces thereof by caps equally suitable for connecting the transducer to a stationary frame, a free end or another similar ultrasonic transducer. A device for pre-stressing electromechanical converters has a hole bored at the centre thereof in order to allow cables from the transducer as well as from adjacent transducers to pass therethrough.