Advantages
- Non-invasive, so no pressure drop
- Measures flow of fluids and slurries that ordinarily cause damage to conventional sensors
- Responds quickly to changes in velocity
- Eliminates local mechanical and electrical noise, permitting use in a variety of locations
- Works with a variety of pipe sizes and flow conditions
- Accommodates flow in either direction
- Measures independently of temperature, pressure, density, viscosity, and electrical conductivity
- Non-contact, lack of moving parts greatly reduce maintenance requirements and sensor fouling
- Easy installation.
Disadvantages
- Doppler: can’t measure gas flow
- Time-of-travel: requires relatively clean fluid
- Excess solids or entrained gases may block ultrasonic pulses
- Requires steady flow, can’t handle wide and/or rapid fluctuations