Modified Durso for CPR Overflow

Discussion in 'I made this!' started by verbal, Nov 19, 2003.

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  1. verbal

    verbal Astrea Snail

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    Hey everyone,
    Just wanted to show some pics of a modification I've come up with for a Durso-inspired standpipe in a CPR overflow. I tried this design first:

    http://home.att.net/~rstockman/overflow.htm

    However, there was too much turbulence created as the water flowed through the holes. I then tried the square notch in the standpipe in place of the holes, but this was no better for me. I had turbulence and, hence, loud noise.

    I tried to come up with a way to create more laminar flow down the pipe. I thought why not just put another tube in there to break up the turbulence.

    I toyed with some flexible tubing at first but then discovered CPVC. I use 5/8" CPVC tube inside the 1" PVC standpipe. I reamed a hole in the original PVC cap large enough to accept the CPVC, then capped the CPVC with the appropriate cap with some holes drilled in it.

    There's some pics below.

    I have a 600gph CPR overflow matched with a ViaAqua 3600 pump in the sump. I guess we're probably getting 400-500gph of flow, and this standpipe has handled this nicely.
     

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  2. Click Here!

  3. verbal

    verbal Astrea Snail

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    Another photo:
     

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  4. verbal

    verbal Astrea Snail

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    One last shot:
     

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  5. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    :eek: :eek: :eek:

    NICE WORK VERBAL!!

    I'm floored. You are a PVC artist! [smiley=beatnik2.gif]

    Any shots of it in action?

    8)
     
  6. verbal

    verbal Astrea Snail

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    Here it is in action:
     

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  7. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    Wow that's smooth. I don't see any turbulance. I think you nailed it! Nice work. :)
     
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  9. Land_Fish

    Land_Fish Guest

    The over flow holding area on the pre-filter looks like it is sealed? Is this true? and how does this work?
    I have heard alot of bad thing when pretianing to CPR overflows so I don't know much about them and never seem them in action.
    I really want to know what I am looking at to cut to the chase here.

    But it looks cool Verbal. Karma coming at ya.
     
  10. verbal

    verbal Astrea Snail

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    The overflow holding area has a loose fitting acrylic top. The big complaint with these overflows is that air eventually builds in the U-turns of the siphon, slowing siphon rates until, potentially, all siphon is lost. CPR has manufactured these units with a port on top of the U-turns to allow hobbyists to remove this air as it builds up (either by mouth or via a pump).

    I must admit that I do see air collecting at the top of the u-turns. I know this slows my siphon rate. I have not however lost siphon entirely, even during power outages. I do suck the air out of the u-turns everyday, though. The standpipe modification has no impact on this property of the overflow.

    Here's a picture showing the air evacuation port and where the air tends to trap. Hope this helps.
     

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  11. verbal

    verbal Astrea Snail

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    And here's a schematic of flow through the unit.
     

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  12. Matt Rogers

    Matt Rogers Kingfish Staff Member

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    I don't see that as a unique flaw to CPR overflows.
    In the old school overflows, I'd get air in the u-tubes too. I'd have to stick an air-line up there and suck it out occasionally. Your way looks easier.