Selection of anemometer and pressure differential measure device for air tunnel

[HilaryE]

Dear All,

I develop a lab air tunnel in order to measure pressure drops before and after a wall of little pills. I send attached the concept of tunnel.

1. I search online stores looking for an optimum anemometer/pitot tube in terms of cost/quality. Expected range of velocities to be measured is 0.1m/s – 15m/s. Velocities at which the pressure drop will be measured are: 0.1, 0.32, 0.46, 1.42, 6, 8.25, 10.5, 12.75, 15. Required sensitivity of an anemometer would be, say, 0.02m/s, as the lowest measured velocities will be 0.1, 0.32, 0.46m/s.

https://www.globaltestsupply.com/pr...2qqobkvzEgRFv4o45v5Y9xpBktjAvz58aAsWQEALw_wcB

Unfortunately, a lot of devices like this from the link has a minimum measurable air velocity 1m/s. Can you recommend some affordable makes/brands of anemometers for low velocities?

2. I am also looking for an air pressure differential measure device (probes for pressure difference measure are marked in green in the attached drawing). Expected pressure differences are in range 0-500Pa. I am looking for a unit that would be an economical option. I find units like this linked below, affordable, but they are not suitable for this application.

https://www.valuetesters.com/uei-em201spkit-digital-differential-manometer-static-pressure-kit.html

Thank you.
Regards

 

[danw2]

I can't help you with a pitot tube or a windmill.

TSI-8475 is a hot wire anemometer (thermal dispersion) meter with a low range down to 0.05 to 0.5m/s

Mechanical Gauge: Dwyer 2000-5000PA, range: 0-500 Pa[ also lower ranges

4-20mA transmitter: Dwyer 607-4 range: 0-2.0"w.c. (498 Pa)

 

[HilaryE]

@danw2
Thank you for your kind reply.
I will check listed meters and hardware.
Thank you.

 

[FacEngrPE]

Devices that measure velocity pressure - pitot probe,, orifice plates - loose accuracy at low flow rates. This is related to velocity pressure being a function of the square of the fluid velocity. Hot wire anemometers are a better choice if you need low end accuracy (they are relatively expensive, and fragile).
If you chose to use a differential pressure device, you may need to use a low range and high range transmitter to get useful resolution (sometimes these can be the same model differential pressure transmitter, scaled differently). Your turn down range 150:1 is too much to expect out of a single differential pressure transmitter, and still have reasonable low end resolution.
Fred