Adeyemi,

Sensirion and TSI both make rather nice flow sensors.

(we use the SFM3000 extensively)

Temperature and humidity? Honeywell HIH-4000 isn't bad, but if you want all-digital, the ENS 210 is our preferred choice.

Hi James -

Thanks a lot for your response. I am following up on them. Sensiron, indeed, has a good sensor for humidity but none for measuring airflow in a vessel without a pipe/duct.

Are you using SFM3000 in a pipe? Do you think it can be used in a non pipe/duct application?

Adeymi,

Yes, these would not be terribly suitable - although it is true that the SFM3000 is essentially an empty tube of constant diameter, there might be some slight reduction in flow. I'll take some photographs later today.

If flow speed accuracy is crucial, I'd go for an 'open' hot wire anenometer.

https://www.dantecdynamics.com/hot-wire-and-hot-film-probes

and

https://www.pce-instruments.com/us/measuring-instruments/test-meters/anemometer-pce-instruments-hot-wire-anemometer-pce-423-det_2131338.htm

if you need a hand-held solution rather than a fitted sensor.

Thanks again James.

In term of accuracy, we are a bit flexible. I will try the SFM3000 and see how we can fit it into the vessel. Will appreciate pictures of how is fitted for your application.

I have also heard about the hot wire anemometer. It will be worth a trial indeed. Thanks

Adeyemi Jinadu

Any thermal method (the SFMs use a micro-engineered hot wire) will be susceptible to the nature of the gas: so a flow of nitrogen at 1 litre/s will have a slightly different reading from a flow of oxygen at the same volumetric flow rate.

But that can be calibrated out. If the gas mix stays constant from one measurement to the next.

Good luck!

I attach some shots down the bore of our SFMs - we use them in a ventilator-like system.

Thanks a lot James. This is very helpful. I will give it try and let you know how it goes.