DIY Overflow and sump Using - Professor Dirk Bellstedt Designs

Hmm was so ready to make some sort of comment, first to mind was drop the T connection to get a bigger difference between syphon and overflow, the other was that you probably had silicon inside the pipe and that that was causing your slow flow rate ... but I felt I had to test this before leaping to a theory.

So .. on my circulating bare bottom tanks I have a return branch that feeds a few small tanks that all via syphon back to the main line. On the one tank I use a overflow/syphon similar to yours except I use the polly fitting that reduces the inside diameter at each fitting.

The experiment - switch off the main pump and let all the flow finish (now the overflow is primed)



I then dumped 13l into the top tank and timed how long it would take to drain it all.



Result it took 5minutes and 12 seconds to drain all 13l.

My conclusion, I am getting double your flow rate - what is the difference? I have not used and glue, my T connector is 1/2 down the nu shape and my inlet pipe is longer than the lowest bend in the nu. Maybe if I used the other connectors I could get better flow - for now this is all I need.


Not sure this helps but it is all I have ;-)

Later Ferdie

 

Ferdie the difference is that you are in Joburg where everything is faster and better and Jubby is in Slaapstad....

Another reason is that your pipe is thicker and you are using internal fittings.

Kind regards,

Dirk

 

LOL - Joburg is only perceived as faster cause people chaise their own tails ... Slaapstadt you chaise any tail.

Back on point .. Prof you made me go digging, green plumbing is 20mm.



Now for the internal fittings allowing for more flow ... it feels right on the syphon side i.e. second elbow from the inlet, but I have no clue why.

 

@f-fish Nice idea of using the pump to prime the overflow
Mine didn't use any glue besides on the air tube section, all the pipes fit together and are totally movable. Helps with adjusting it to hold onto the tank nice and tight.

I think having the T junction lower is causing more pressure thus the improvement in flow rate.

5 min for 10 liters = 110 liters a hour..
But 100 - 200 liters a hour is still on the very low side

How are these illusive figures of 1000 liters a hours achieved ?
Doubling the pipe diameter 40mm is going to cause a 10 x more flow? really ?

@stombringer101 are you going to be using an overflow system ? built it yet ? what kind of flow rate are you getting and what size pipe did you use ?

 

If I may... working in the chemical industry has its benefits. I'm going to refer to 3 things. Pipe diameter, flow and pressure. Seeing as we are looking at a gravity system it is safe to say that the pressure will have little if any fluctuation. Due to the pressure constant the flow will react as follows... I don't have the formulas with me now so I'm using example values. If a 20mm pipe allows a gravitational flow of 200l/h (used as a reference value). A 25mm pipe will allow 400l/h flow where a 40mm pipe will tenfold the flow to 2000l/h. The bends be it 45 or 90 degree bends won't affect your flow because of the hydraulic concept. All the bends will do is slow the velocity which will lower your exit pressure due to it being an open ended system.

 

I did some calculations and here are the scenarios... These calculations are with no head pressure and no compensation for upward flow in the overflow system. Plain and simple water down a pipe at gravity. (So please don't crusify me if you try these specs and flood the house)


Scenario 1. Pipe length = 150cm (Average length of a filter pipe). Drop = 100cm (average height from tank edge to floor). Roughness coefficient = 150 (General smoothness value of plastics).

20mm Pipe = 4080l/h
25mm Pipe = 7380l/h
32mm Pipe = 14100l/h
40mm Pipe = 25380l/h

Scenario2. Pipe length = 150cm (same as above). Drop = 150cm (For the guys with higher displays). Roughness coefficient = 150 (Same as above).

20mm Pipe = 5100l/h
25mm Pipe = 9180l/h
32mm Pipe = 17580l/h
40mm Pipe = 31620l/h

As you can see the flow drastically increases as the pipe diameter increases... Not sure how to compensate for the upward flow section. Maybe the educated forumites can lend a hand.

 

Great Double D,

At last we are getting a professional involved, pipes, flow rates and pumps are not rocket science and have all be done before, so this is not such a difficult problem to crack. Thanks for giving the advice and then Jubby can finally overflow

Kind regards,

Dirk

 

No problem prof @Dirk Bellstedt

Flooded enough rooms in my life...

P.S. When you feel better and have some time available I posted those angels we spoke about at the expo :amuse:

 

Will have a look there.....

 

As I've said in the past... increasing the pipe increases flow EXPONENTIALLY. You are getting MORE than 10x based on the figures we've just seen.

 

Ok I re did it with 40mm internal diameter pipe, exact same design/bends elbows as the last time ..
Allot more flow about 600 liters a hour..

Any more suggestions ?

 

Hi Juddy,

Your pump is obviously much too strong, you are trying to get a victoria Falls into your aquarium which is not feasible.

 

I think you are right professor, Think i should says "done and working perfectly" ?

its a 200 liter tank so 600 liters a hour should be good enough for the sump ? I will just restrict the pump a little and call it an experiment well done

 

How is butcherman getting 1500 with what looks to be the same size pipe and bends,

I see the last join is a "y" joint will that be better then the T joint i am using

 

Oh P.S thank you once again to @Zoom @Dirk Bellstedt @Double-D @stormbringer101
and the rest of the participants in this thread for all your assistance with my little DIY project

I have learned allot .. and hopefully i am a better plumber/builder and fish keeper because of it

 

Juddy,

I have all along thought that you have not understood my whole endlessly long thread and your last comments prove that you have not understood it. Flow rate alone does not decide the efficiency of a biological filter it is the volume of the biological filtration medium (note not mechanical filtration medium) that decides how effective a biological filter is. You need to read through that thread again because you are just trying to force the flow rate which is not what it is about. READ OLD THREADS AGAIN AND AGAIN TO UNDERSTAND THEM!

Kind regards,

Dirk

 

I know you are right, i will re-read

I just keep thinking along the lines of "the minimum turn over recommended by LFS and filter sales men"
and should be aiming for quality filtration over quantity.

 

It is far easier to suck out the little bit of air in 2 than to try and get the syphon going. The end of which might not be that easy to reach.

 

I added in the air-pipe to suck out the air .. but now I am scared that I might have a small slow air leak ..maybe thats reducing the flow..

I am running a test now .. and the water level in the tank seems to be raising by about 1mm an hour.
It will take a long while but if it continues at the rate the tank will eventually overflow.. so I need to reduce the size or flow of the .

Ideally i think the pump head must be below that of the overflow flow rate so it can never drain the sump or overflow the tank..