Different type of Flow element
1.Differential Pressure
Orifice plate Pitot Venturi
Advantages - Simple,No moving parts.
Disadvantages - Susceptible to wear in dirty services except vertically. Orifice edge sharpness affects accuracy.
2.Turbine Rotor
Advantage - No moving parts
Disadvantages - Moving parts can wear.
3.Vortex
Bluff body
Advantages - No moving parts.
Disadvantages - Bluff body can corrode.
4.Positive Displacement
Oval gear Sliding vane Nutating disk
Disadvantages - Many moving parts subject to wear. Prefilters for dirty service.
5.Coriolis/Mass/Thermal Mass
Advantages - Very low maintenance (Coriolis) No moving parts,corrosive fluid may effect element.
6.Magnetic Field
AC Field DC Field
Advantages - Low maintenance element [