Patent ID: 7506532

Claim:
A method for calibrating ultrasound clamp-on flowmeters, comprising: arranging radiating surfaces of two sound transducers acoustically opposing one another in planes that are mutually parallel; positioning said sound transducers at a mutual distance x0+xd in a first position, x0 being the distance for optimum acoustic coupling of said two sound transducers and xd being the deviation from this position that is designated as the deviation; measuring a sound transit time t1 between said sound transducers in said first position; repositioning said sound transducers at an other mutual distance x0+xd+Δx in a second position; measuring an other sound transit time t2 between said sound transducers in said second position; and calculating an acoustic calibration factor Ka from the distance difference Δx and the time difference Δt=t2−t1 using the formula Ka=Δx/Δt.