If you need to measure flow in systems with stable pressure and
temperature (between -20oC and +240oC) - natural gas flow to boilers and
dryers, compressed air metering, steam metering or gas metering in
breweries, for example - then Spirax Sarco’s new VFM 3000 digital vortex
flow meter could be the instrument for you. It uses a signal conditioner
that processes pulses from two internal piezoelectric sensors to provide
a 4-20mA signal that is proportional to flow rate. Accuracy is within
+/-1% of measured flow, and the instrument has a typical turn-down ratio
of 12:1 (though this will depend upon the gas being measured). The meter
body is manufactured in 316L stainless steel with a titanium alloy vortex
shedder, making it suitable for use with corrosive gases and clean steam.