Exhaust Scrubber Flow Measurement

[lvaldez1350]

I am looking for a device that will contiuously measure flow on the inlet of an exhaust scrubber. I need it to be a permanent installation with a 4-20mA output so it can be hooked up to a PLC or other control system. The scrubber has a 36" round duct on the inlet and has flow rates around 30,000cfm. Any help with locating methods and manufacturers would be greatly appreciated.

 

[dpoppeli]

This Dwyer unit looks promising but I would check with the manufacturer. You would be measuring a peak velocity with the 18" probe but you said you were running this through a PLC so you could average the velocity into a CFM output.

http://www.dwyer-inst.com/htdocs/airvelocity/qsseries641.cfm

 

[lvaldez1350]

thanks dpoppeli for the help!

 

[quark]

Generally it is done with pitot tubes and a dp transmitter. The one suggested above is a good one which can take care of velocity variation across the width of duct. But you should have proper temperature calibration for exactly knowing the heat flowing out of the heated element. Moreover the error is high. (but it seems to be ok for your application)

The best bet can be an annubar, if you are flexible with your budget.

http://www.rosemount.com/products/flow/m485ann.html

Good Luck,