Measuring Principle - After the doppler procedure,the ultrasonic flow-meter sends out an ultrasonic signal (usually 1 to 5 MHz) in an angle in the measuring tube. Parts of these ultrasonic signal send reflecting particles back to the receiver.The reflected float moves in the direction of or away from the sender, the frequency of the returned signals deviates from the original signal.
Advantages of Ultrasonic Doppler Flow-meter
1.Simple assembly of existing pipes 2.Not intrusive,no maneuverable part,no pressure loss 3.Wear free 4.Suitable for media with solid interest
Disadvantages of Ultrasonic Doppler Flow-meter
1.The speed of the particles and the reflecting and scattering effects can generate false measurement 2.Speed of sound of the particle material must strongly differ from that of the fluids. 3.High flow velocity speed of the media is essential,otherwise the particles tend to rest in the pipes. 4.Ultrasonic field is frequently deflected directly in the boundary current.Thereby strong dependence on the flow profile