From Flow Measurement
Variable area flowmeters were invented in the nineteenth century but were not
introduced for general industrial use until the 1930s. They became very popular
and widely used since they offered a low-cost alternative to the differential pressure
flowmeter-especially in smaller pipe sizes.
The original designs introduced were available for visual indication of flow rate
only. In the 1940s designs became available with secondary functions such as
transmission, alarm, recording, and totalizing. Variable area flowmeters are available
in pipe sizes from 1/8 inch (0.3 cm) to 8 inches (20 cm) and full scale flow
rates from less than one ml/minute to over 1000 gpm (3800 lpm) of water and
approximately 30 scc/minute to 2500 scfm (71 nm3/min) of air.
Since they are in-line devices, they have been designed for a wide range of line
pressure ratings, pipe connection types, and many different materials of construction.
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Topics of Interest
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