Question

Compare variable head flow meter with variable area flow meter.

Answer 1

Parameter	Variable head flowmeter	Variable area flowmeter
Working principle	Restriction or obstacle is placed in the path of flow to create a differential Pressure.	The pressure difference is kept constant by changing the restriction area.
Basic Construction	The construction depends on the type of primary element used. Accordingly these are of the following types 1) Orifice plate 2) Venturi tube 3) flow nozzle	Tapered transparent glass tube with lesser diameter at the bottom fitted with a metal float inside, called rotameter.
Maintenance cost	minimum	minimum
Use	Used in viscous fluid slurries and dirty fluids.	In laboratories and testing and production lines.