Results 1 to 9 of 9
  1. #1
    Join Date
    Aug 2010
    Location
    windhoek
    Posts
    41
    Rep Power
    0

    air flow metering



    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



  2. #2
    Join Date
    Sep 2007
    Location
    Split Croatia
    Age
    57
    Posts
    6,175
    Blog Entries
    6
    Rep Power
    36

    Re: air flow metering

    Quote Originally Posted by mechman View Post
    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/Pr...ccuBalance.jpg
    Last edited by nike123; 19-09-2010 at 09:51 AM.

  3. #3
    Join Date
    Aug 2010
    Location
    windhoek
    Posts
    41
    Rep Power
    0

    Re: air flow metering

    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?

  4. #4
    Brian_UK's Avatar
    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    76
    Posts
    11,192
    Rep Power
    60

    Re: air flow metering

    Quote Originally Posted by mechman View Post
    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.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  5. #5
    Join Date
    Aug 2010
    Location
    windhoek
    Posts
    41
    Rep Power
    0

    Re: air flow metering

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

  6. #6
    Brian_UK's Avatar
    Brian_UK is offline Moderator I am starting to push the Mods: of RE Site Moderator : and general nice guy
    Join Date
    Mar 2001
    Location
    Dorset
    Age
    76
    Posts
    11,192
    Rep Power
    60

    Re: air flow metering

    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.
    Brian - Newton Abbot, Devon, UK
    Retired March 2015

  7. #7
    Join Date
    Aug 2007
    Location
    Sydney
    Age
    51
    Posts
    1,094
    Rep Power
    23

    Re: air flow metering

    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.

  8. #8
    Join Date
    Aug 2008
    Location
    Baltics
    Age
    62
    Posts
    786
    Rep Power
    16

    Re: air flow metering

    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!

  9. #9
    Join Date
    Dec 2010
    Location
    Fl,United States
    Posts
    16
    Rep Power
    0

    Re: air flow metering

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

Similar Threads

  1. flow switch connection
    By afeef in forum The Trail of Tears
    Replies: 18
    Last Post: 23-12-2009, 07:55 PM
  2. Pulling faster vacuums
    By Aranon in forum Fundamentals
    Replies: 31
    Last Post: 04-09-2009, 07:32 PM
  3. Flow Rate through Fan Coil Unit
    By deepu in forum Air Conditioning
    Replies: 4
    Last Post: 21-07-2009, 06:42 AM
  4. Capillary Tube Characteristics
    By Chef in forum Fundamentals
    Replies: 9
    Last Post: 10-03-2009, 02:03 PM
  5. High Liquid Line Temperature
    By airefresco in forum Commercial
    Replies: 37
    Last Post: 11-02-2009, 05:36 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •