air flow metering

[mechman]

Hi
what is the most suitable way of air flow metering in a duct and at a diffuser outlet.

Please let me have your oppinion

[nike123]

Hi
what is the most suitable way of air flow metering in a duct and at a diffuser outlet.

Please let me have your oppinion
http://testousa.com/435/

http://www.tsi.com/uploadedImages/Product_Information/Images/Large/8371_AccuBalance.jpg

[mechman]

how practical is it to use a pitot tube to determine the velocity (velocity pressure) in a duct? i.e if the pitot tupe is not held 100% perpendicular to the flow?

[Brian_UK]

how practical is it to use a pitot tube to determine the velocity (velocity pressure) in a duct? i.e if the pitot tupe is not held 100% perpendicular to the flow?
The pitot tube is the most reliable method that has been used for years.

You have to be a long way off line before the readings go silly, most people are able to hold the tube steady while the readings are being taken.

Just make sure that you set up the duct traverse points correctly.

[mechman]

how about a hotwire anemometer, or is the pitot tube more acurate?

[Brian_UK]

Pitot tube and manometer would be the most accurate of those two.

It also depends on how accurate you need to be for the application involved.

[Tesla]

At the outlet and on a coil a velocity grid is the most accurate and reliable. This is used by many air balancing companies and some manufacturers now have them built into the duct. For one off measurement in the duct the pitot tube is used.

[Yuri B.]

Apropos the air flow metering at difusers outlet.

Have made a use of this instrument recently

http://www.kimo.fr/?rt=index/getFt&id=430

Was turning open a difuser - it showed growing flow. Screwed the diffuser off at all - flow rate shown dropped almost by half!

[DC5-T]

Testo meters all the way, they have proven themselves in the Hvac field