45 or 90 elbow. Does it really matter?

Discussion in 'Equipment' started by Vhuang168, Feb 25, 2017.

  1. Vhuang168

    Vhuang168 Supporting Member

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  2. roostertech

    roostertech reef noob

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    I think at 1" pipe diameter, the difference won't be that visible. I'll be more interested in the same test for 3/4 and 1/2
     
  3. yellojello

    yellojello Guest

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    Read the comments. Looks like drain might have more of a difference because of air pockets?
     
  4. jonmos75

    jonmos75 Supporting Member

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    There can be difference but not significant as a 45 degree reduces the flow of half what a 90 degree fitting does, yet you need (2) 45's so they almost become equal in flow loss.

    Here is a chart of flow restrictions based on pipe size and fittings
    http://www.engineeringtoolbox.com/pvc-pipes-equivalent-length-fittings-d_801.html

    The FMM with flow sensors has shown a lot of the NSI beta testers they did not have as much flow in their tank that the originally thought and plumping plays a big factor in reduction of flow.
     
  5. sfsuphysics

    sfsuphysics Supporting Member

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    I wasn't a fan of how they did that test setup, two 45s next to each other that makes a gradual 90. Now whether or not that makes a difference is to be seen, but maybe they should have found a way to do that test with a single 45 vs a single 90 and see if there was any noticeable difference, then bump it up to 2 45s vs 1 90.
     
  6. rygh

    rygh Supporting Member

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    Just over size the pipe a bit, and you can pretty much ignore all that nonsense.
    Larger pipe = lower velocity.
    lower velocity = less kinetic energy change at elbows, and less friction in the pipe.
    But not just by a little!
    Pipe volume is a function of the square of the diameter.
    Friction and kinetic energy is a function of the square of the velocity.

    So: Doubling a pipe from 3/4" to 1.5" pipe = 1/16 the losses.
     
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  7. xcaret

    xcaret Supporting Member

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    I've never put too much attention to the math involved in flow loss; ~5' of head loss when I had the tanks was not a crucial thing for me but If I had to be pumping a la CalAcademy style reef, then yes, lots of numbers to figure or for those of you guys who have a tank on the main floor, sump in garage or basement then I guess would be a pretty good issue to deal with.
     
  8. Flagg37

    Flagg37 Colorado member

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    Not only that but the ratio of volume to surface area is much less with the larger plumbing.
     

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