Transit time ultrasonic clamp-on transducers are clamped on the outside of a closed pipe at a specific distance from each other. The transducers can be mounted in V-mode where the sound transverses the pipe two times, W-mode where the sound transverses the pipe four times, or in Z-mode where the transducers are mounted on opposite sides of the pipe and the sound crosses the pipe once. For further details, reference pictures located under Table 2.2. The appropriate mounting configuration is based on pipe and liquid characteristics. Selection of the proper transducer mounting method is not entirely predictable and many times is an iterative process. Table 2.2 contains recommended mounting configurations for common applications. These recommended configurations may need to be modified for specific applications if such things as aeration, suspended solids or poor piping conditions are present. W-mode provides the longest sound path length between the transducers – but the weakest signal strength. Z-mode provides the strongest signal strength – but has the shortest sound path length. On pipes smaller than 3 inches [75 mm], it is desirable to have a longer sound path length, so that the differential time can be measured more accurately.
Post time: Jun-19-2022