gas flow measurement


Thread Starter


I'm looking to set up a "cheap and cheerful" system to monitor the amount of nitrogen gas our equipment uses on a 24/7 basis.

I would like to install it individually on a per machine basis; I was thinking of a flowmeter connected to a small plc or something.....

The nitrogen comes in to the machine(s) from a standard 1" pipe or something like that....

Also, I would like to be able to look at any arbitrary window of time and see the quantity of nitrogen that was used for that period...

Does anyone know of specific flowmeters or other devices that would work well?

Remeber folks, I'm a "simple simon", so keep it basic for me!!
Any flowmeter will do.
Your pipe size is small for accurate orifice plate, but yes. Rotameter c/w XTR: Ok
Vortex: yes, Yokogawa have size down to 3/4 "

Keven Dunphy

Good morning "Simon"...

A flow solution from Micro Motion would fit the bill. An R-Series Flow
Meter would cost you less than $2800. It would require no straight pipe
run, and would be immune to changes in static pressure or temperature...
this would certainly seem to fit the goal of simplicity. It would output
a 4-20mA signal as well as incorporate a local display with totalizer.

If you would like more information, please check out the website at or phone the Customer Support Center at

Keven Dunphy
Process Gas Marketing Manager
Micro Motion, Inc
a Division of Emerson Process Management
303 530 8048
Here's what you do, and it is simple.

Pick your flowmeter of choice. Properly sized, a turbine would work well.

Make sure it has a scaled pulse output (a frequency output).

Connect the scaled pulse output to the PLC.

Write a totalizer register for the PLC. (new pulse added to all old pulses)

You can write as many totalizer registers as you wish (last minute, last hour, last shift, last day, etc.)

Either pick a PLC with a datalogging function, or use a simple single channel pulse datalogger (available from many companies, and private labels)

That's the simplest and easiest way to do the app.

Walt Boyes
Contributing Editor
Flow Control Magazine