1. Hi Ronan,

I just found this great site this week, and have been reading every post until my head hurts. Once I saw your thread on figuring out flow rates and head loss I felt like i was back in school. I love this stuff. Anyway, I have a chemical engineering degree and plan to figure out your TPR Examples on my spare time. Hopefully this will help me keep my engineering skills fresh.

I was also wondering if the BF drain gap equation changes if you add a diffuser?

Thanks alot
Newbie

2. welcome to the forum.

as far as bottom drain dome gap height and air diffuser. the air diffuser won't nesserally effect the gap height. but the air diffuser will effect the water currents coming along the bottom of the pond.

in realty, aerated bottom drains can cause more boyunt ( lighter debrie ) from making it down into the drain. due to there is a more projected current upwards and away from the drain. due to the air diffuser in essence is forming a simplified air lift pump.

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as far as hitting on your engineering skills. the goal of TPR's ( trigental point returns ), air diffusers on dome of bottom drains. is to provide extra current within the pond. which can be translated into velocity of the water. the faster the water is moving. the less likely a single peice of debrie will settle out of the water and stick to the pond bottom.

the TPR's help keep the outer rim of the pond water currents at a higher velocity. ((outer edge of pond bottom ))

if you looked at water currents from a aerated bottom drain. you would see something like a donunt shape. and with this takes care of the middle portion of the pond (( between wall and drain )) (( maintains higher velocites across middle portion of pond bottom.))

then the drain gets the area nearest to the drain. in keeping up the higher velocites. (( centter of pond bottom ))

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and to rehit on the gap height. the gap height is to deal with friction loss (( dynamic head loss )) at the dome. if you set the dome to low to pond bottom it would be like shutting a valve, and causing dynamic head loss.

setting the dome too high. and you loose coverage area around the dome, that the drain itself keeps clean.

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all in all. the air lift pump calculations are still above my head.

all in all. the calculating of the velocities area the bottom drain measures x amount away from bottom drain are still above my head.

i am not an engineer. never graduated from highschool and only a couple computer collage classes. so if i am wrong plz correct me!

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just to re-hit on the question of yours. if you streched it all out. i could possible for see a yes to your question about gap height and an air diffuser on the dome of a bottom drain. but at that point i think you would be getting into some sort of fluid dynamics that would fall into say an engine or some sort of specialized container. were there is a critical point of tring to mix something or keep liquids from mixing as they went down the drain.
Last edited by boggen; 02-24-2007 at 02:14 AM.

3. Originally Posted by boggen
TPR's, SQUARE shape pond.

the goal of below info and diagrams. is give idea of were to place tprs and what they can do to help keep the pond itself clean of muck and debrie, and fish poo, and etc...

everyone pond is different, and because of that, i ask that you apply the info. just don't take it on blind thought.
1. no drains, no TPR's, all the debris just collects in bottom of the pond
2. simple a bottom drain. with a pond size bigger than what the bottom drain can suck into it.
3. air diffuser on top of the bottom drain.
4. single TPR. note it throughs symetry of the water currents in the pond way off
5. 2 TPR's symtrey is not completely achived. 2 corners have more debrie build up than other 2 corners.
6. 4 TPR's symtry is achived
7. 1 tpr, coming out the side of pond with a 90 inside the pond.
• this can be a bad thing. with stuff sticking into pond. mainly due to fish can bumb into it and harm themselves. if you have ever witness fish spawning, you would truely understand how much the males shove the female around. (( think a bunch of 5 year old kids that were all given lots and lots of surgar and caffine ))
8. 2 tprs, coming out pond side with a 90's inside pond. symetry not completey achived.
9. 4 tprs, coming out pond side with a 90's inside pond. symetry achived
10. TPR's pointed directly at drain. aka no debrie is removed from pond.
square ponds or rather trap crap corner ponds. are abit of a pain to deal with. mainly due to the corners will love to collect debrie and muck. its just something of matter of life when dealing with sharp corners.
• the thought behind diagrams 4 - 6, is to show a safe way to add tprs to a pond, and keep fish from banging into them.
• the thought behind diagrams 7 - 9, is to show a way of point tprs into corners to clean them out.
• sadly, they require plumbing inside the pond. my personal preference is i don't like to see plumbing inside a pond. than and fish can harm themselves on stuff inside a pond.
• the postioning of tprs is not a great use of tprs. granted they may clean the corner, but you loose alot of effective-ness for the rest of the pond bottom in keeping it clean of debriee and muck.
In diagram #6, are those TPR pipes sticking out into the pond? Are they angled down at all? Thanks

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