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-   -   Water pressure/flow rate (https://www.askmehelpdesk.com/showthread.php?t=212713)

  • May 5, 2008, 07:12 AM
    wizy
    Water pressure/flow rate
    Can water pressure be estimated from flow rate from a known size of pipe. I`m in the UK so metric units would be best for me

    Many thanks Michael
  • May 5, 2008, 07:41 AM
    massplumber2008
    Wizy:

    I just asked Capuchin to drop in...

    I believe capuchin is expert over in Mathematics... also from UK, I think..? Should be able to resolve your question... good luck.

    Give Capuchin some time to get to your post... Mark
  • May 5, 2008, 08:15 AM
    Capuchin
    Pressure only depends on the height of water.

    Hydrostatic Pressure in a liquid

    This page explains it quite well.

    If you have no way to measure the height of your system, then you'll have to give me some time to look into how the pressure affects the flow rate - or hopefully one of the other experts can help - I'm a little busy at this time of year.

    Mark, for your information, I'm a science expert - specifically physics, which regrettably means I need to know some math ;)
  • May 5, 2008, 08:53 AM
    massplumber2008
    Duly noted Cap!

    Thanks for popping in... Mark
  • May 5, 2008, 05:23 PM
    jlisenbe
    This one ought to be interesting. Just out of curiosity, why wouldn't you simply put on a valve and pressure gauge?
  • May 9, 2008, 08:54 AM
    wizy
    Quote:

    Originally Posted by Capuchin
    Pressure only depends on the height of water.

    Hydrostatic Pressure in a liquid

    This page explains it quite well.

    If you have no way to measure the height of your system, then you'll have to give me some time to look into how the pressure affects the flow rate - or hopefully one of the other experts can help - I'm a little busy at this time of year.

    Mark, for your information, I'm a science expert - specifically physics, which regrettably means I need to know some math ;)

    Capuchin Thanks for the reply My problem is with the mains cold feed so not possible to measure the head of water. The link page looks interesting, I'm busy to so going to take me a while to wade through the information
  • May 9, 2008, 09:10 AM
    wizy
    Quote:

    Originally Posted by jlisenbe
    This one ought to be interesting. Just out of curiosity, why wouldn't you simply put on a valve and pressure gauge?


    jlisenbe Thanks for the reply The quick answer is I haven't got a pressure gage!!

    I feel pressure, flow rate/pipe size, volume and time must be linked if you have any 3 the 4th could be calculated?
    It would be a simple matter to measure an amount of water into a container over a set time the pipe size being known the volume of water being driven by the pressure? i.e. the unknown quatity
  • May 9, 2008, 02:52 PM
    jlisenbe
    Let us know how it works out. Sounds interesting.
  • Apr 24, 2010, 05:39 PM
    Nhan123
    Quote:

    Originally Posted by wizy View Post
    jlisenbe Thanks for the reply The quick answer is I haven't got a pressure gage!!!

    I feel pressure, flow rate/pipe size, volume and time must be linked if you have any 3 the 4th could be calculated?
    It would be a simple matter to measure an amount of water into a container over a set time the pipe size being known the volume of water being driven by the pressure? ie the unknown quatity


    Mathematically: Flow (L/m) = Pressure (psi) * Resistance

    Now you'll need to determine the Resistance of your pipe. The
    Resistance is a function of the pipe's internal diameter (ID) times its length (m).

    Do you still want to continue setting up this mathematical formula on or to buy a pressure gauge for $10.00? :)

    p.s.: I think you still need to know your pipe's Resistance in your volume & time idea.

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