Method and assembly for ultrasonic clamp-on flow measurement, and bodies for implementing the measurement

A method for ultrasonic clamp-on flow measurement, comprising a process pipe through which a liquid or gaseous process medium flows, center sound paths and off-center sound paths being taken into account, and comprising clamp-on ultrasonic transducers, the method comprising:

• injecting ultrasonic waves into the process pipe and into the process medium via at least one clamp-on ultrasonic transducer operating in a transmit mode;
• dispersing the ultrasonic waves within the process pipe via at least one body, which is disposed in an interior of the process pipe and used to implement a measurement of off-center sound paths;
• preventing a total reflection of the dispersed ultrasonic waves when the dispersed ultrasonic waves cross a boundary from the process medium to the process pipe via at least one second body, which is disposed on an inner wall of the process pipe and is used to implement a measurement of off-center sound paths so that the dispersed ultrasonic waves may leave the process pipe;
• receiving undisturbed ultrasonic waves of the center sound paths via the at least one first clamp-on ultrasonic transducer operating in a receive mode;
• and
• receiving dispersed ultrasonic waves of the off-center sound paths via the at least one second clamp-on ultrasonic transducer operating in the receive mode.