NEW-TECHNOLOGY FLOWMETERS
	Coriolis	Magnetic	Ultrasonic	Vortex	Multivariable differential pressure
Paradigm case application	Clean, medium- to high-speed liquids and gases in pipes of 2 inches or less	Clean, conductive liquids flowing through a full pipe	Clean, swirl-free liquids and gases of known profile	Clean, low-viscosity, swirl-free, medium- to high-speed fluids	Clean liquids (L), steams (S), and gases (G)
Fluids	L, G, S	L	L, G, S	L, G, S	L, G, S
Disadvantage	Price; limited line sizes	Doesn't meter nonconductive fluids	Transit time requires relatively clean fluids	Affected by vibration; somewhat intrusive	Permanent pressure drop-depends on primary element
Advantage	Accurate	Nonintrusive; minimal pressure drop	Nonintrusive; minimal pressure drop	Minimal pressure drop; accurate	Reduced cost; integrated solution
Principle of operation	Mass flow proportional to amount of twist in tube	Flow rate proportional to amount of voltage generated when liquid moves through a magnetic field	Flow rate determined by difference in time it takes an ultrasonic pulse to travel upstream vs. downstream	Flow rate proportional to number of vortices generated by bluff body	Measures mass flow by inferential method, measuring pressure and temperature

TRADITIONAL-TECHNOLOGY FLOWMETERS
	Differential Pressure	Positive Displacement	Turbine	Open channel	Thermal	Variable area
Paradigm cases	Clean liquids, steams, and gases	Clean, noncorrosive liquids and gases	Clean, steady, medium- to high-speed flowing liquids or gases	Clean, free-flowing streams or partially filled pipes	Clean gases of known heat capacity	Clean liquids and gases where high accuracy is not required
Fluids	L, G, S	L, G	L, G	L	L, G	L, G
Disadvantage	Permanent pressure drop-depends on primary element; orifice plates subject to wear	Moving parts subject to wear; requires clean fluids	Moving parts subject to wear; requires clean fluids	Weirs and flumes require obstruction; pressure loss depends on technology	Limited use for liquids; low to medium accuracy	Low accuracy; many do not have output
Advantage	Low cost; well understood	Accurate: measures low flow rates and viscous flows	Reliable; well understood	Limited accuracy, depending on technology	Low cost; measures mass flow	Low cost; many do not require power
Principle of operation	Flow rate proportional to amount of pressure drop created by constriction in pipe	Fluid trapped into compartments of known volume and emptied; flow rate determined by counting how often this happens	Flow rate proportional to speed of spinning rotor	Level or depth used to determine flow with weirs and flumes; area velocity measures flow rate and level or depth	Flow rate proportional to speed with which heat dissipates in the fluid	Flow rate indicated by how high the fluid lifts a float

Source: Flow Research, Inc. (www.flowresearch.com)

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