Title: 370.011 OE501 Siemens Sitrans FUE080 Flowmåler.pdf
Velocity distribution along sound pathA sound wave travelling in the same direction as the liquid flow arrives at point B from point A in a shorter time than the sound wave travelling against the direction of flow (from point B to A).The difference in sound transit time indicates the flow velocity in the pipe.Since delay time is measured at short intervals both in and against flow direction, temperature has no influence on measurement accuracy.SITRANS F US flowmetersIn SITRANS F US flowmeters the ultrasonic transducers are placed at an angle θ in relation to the pipe axis. The transducers function as transmitters and receivers of the ultrasonic signals. Measurement is performed by determining the time the ultrasonic signal takes to travel with and against the flow. The principle can be expressed as follows:v = K × (tB,A – tA,B) / (tA,B × tB,A) = K × Δt/t² where v = Average flow velocity t = Transit time K = Proportional flow factorSITRANS FUS080 transmitter