Large volume laminar flow machine

[Gorgok]

If going that direct i would ditch the whole snake in the back and just make the box ends and join the two with a pvc pipe outside the tank with bulkheads. Now if you could find 8" bulkheads...

 

[JamesHolt]

If going that direct i would ditch the whole snake in the back and just make the box ends and join the two with a pvc pipe outside the tank with bulkheads. Now if you could find 8" bulkheads...

Ask and ye shall receive

https://flexpvc.com/cart/agora.cgi?p=Bulkhead-Fittings-Sch80&p_id=8170-080&xm=on&ppinc=detail

Never under-estimate The power of Google-Foo... :lolspin:

 

[karimwassef]

I think using a bulkhead and PVC in this case may take more room and impede flow much more than the sealed acrylic ducting.

When I started this thread, I said that powerheads and propellers don't address the need because all they do is locally recirculate the flow in a tight loop and can't reproduce bulk flow. They also can't replicate the massive flow. Individually, that's still the case...

But by
using them in an array,
and individually caging them to pull volume from the other tank end,
and using two opposing cross-synchronized sets,
that don't need special valves and actuators,
with straight flow pumps (like the torpedo pump),
with low impedance to reversed flow,
and the flexibility of full programmability,
in a fully sealed ducted loop,
that's fully submerged and guided,
with no external seals or moving parts,
and completely covers both sidewalls,
with laminarizing boxes,
to create an alternating gyre,
I think this has inherited the elements that you've all helped me integrate.

We're close... Just need a baffle box that takes a propeller's output and ducts it into a straight 8.5" x 8.5" laminar flow using only 6" of total distance in front of it.

 

[karimwassef]

I knew I'd seen this stuff before...

I'm thinking of starting with this kind of structure and then going straight and parallel.

 

[karimwassef]

http://www.alibaba.com/product-deta...1768096482.html?spm=a2700.7724838.35.1.gNrSc6

These look promising. They need to be cut to size and then followed up with several stages of eggcrate to direct the flow forward.

 

[karimwassef]

ok. it fits, but it needs a guidebox before it and then straight baffles after it, and then an eggcrate

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[herring_fish]

How does a torpedo pump work and why is it better than others for this application?

 

[karimwassef]

torpedo is a brand name for a straight through pump. One of the thread contributors introduced it a few pages back.

I like the idea so much that I combined it with the propeller concept to come up with the latest version.

 

[herring_fish]

But how does it work. Is there a propeller inside to what?

 

[herring_fish]

Is there no way to actuate them. I know, I know but it really wouldn't be that hard.

If they could turn around, say 120 or 90 degrees, they could blow into the tank and them blow down the sidewall box toward the back of the tank to revers the slow with close to twice as much flow.

 

[Gorgok]

Ask and ye shall receive

Never under-estimate The power of Google-Foo... :lolspin:

Yeah i suppose i should have mentioned reasonable... Grainger had some I looked at for ~500 i think. At no pressure you need roughly a 8" pipe to flow the volume the powerheads (~40000gph) combined can move, so it should work, at least based on the chart i read. If the cost were reasonable it would make sense to make a smaller tank with a pipe instead of the complex snakebox in a larger tank. But at ~$2000 its probably cheaper to get a bigger tank and face the headache of making the snakebox fit in the tank (or assemble in place).

Still not sure you will have enough straightening of the flow with the powerheads that direct to output... I was visioning putting them in the back corners of the snakebox to blow across the whole back and have it loop to the front from the far side bend. But as said, that has other issues of the flow past the other set of powerheads being disturbed.

But as is, are you planning to have a un-braced tank so that the snakebox can be dropped in once assembled? Or add bracing after the snakebox is set in?

 

[JamesHolt]

Karimwassef,
What do think about these instead of a power head setup..

http://www.hotwoods.com/iceeater.htm

 

[karimwassef]

Yeah i suppose i should have mentioned reasonable... Grainger had some I looked at for ~500 i think. At no pressure you need roughly a 8" pipe to flow the volume the powerheads (~40000gph) combined can move, so it should work, at least based on the chart i read. If the cost were reasonable it would make sense to make a smaller tank with a pipe instead of the complex snakebox in a larger tank. But at ~$2000 its probably cheaper to get a bigger tank and face the headache of making the snakebox fit in the tank (or assemble in place).

Still not sure you will have enough straightening of the flow with the powerheads that direct to output... I was visioning putting them in the back corners of the snakebox to blow across the whole back and have it loop to the front from the far side bend. But as said, that has other issues of the flow past the other set of powerheads being disturbed.

But as is, are you planning to have a un-braced tank so that the snakebox can be dropped in once assembled? Or add bracing after the snakebox is set in?

I considered the external tank and plumbing and the headaches there were larger IMO than the channel box (much prefer channel or duct to snake )

The tank being only 24" high and the overflow set at 20" should reduce the pressure enough to not need bracing.

Having said that, I haven't found any builders who would consider it. The engineering margin with a thick glass ... It's there! But commercially, they won't do it. That means I'll likely have to accept the channel section as a built-in glass duct. The plastic ends can then be slid in through the DT. The attachment and maintenance access... Unsolved.

Also need to consider the penalty of an enclosed glass duct that is permanently inaccessible... Still, we bury massive underground piping all the time.

In terms of where to place the pumps. Pointing straight down eliminates the need for any complex baffles or ducting. In fact, I expect that the flow I'm looking for will be perfectly emulated in the inaccessible glass duct ... Amazing, right? Damn the need for an open top tank!!

The straight pump location means that all the energy is basically in the right direction already. It also means that they're not creating a blocage in the duct. The overall impedance is very low... There's also no chance with recirculating flow between the pumps in this orientation.

I've basically packed all the difficulties and pains in the design and put them in the 6" in front of the propellers. But... I think that is manageable, adjustable, fixable, and maintainable. It's even got a decent price tag and low power usage...

 

[karimwassef]

No actuators, motors, grease, valves, bulkheads, or massive expensive piping. It's simple...

Until you get to the output section.

 

[karimwassef]

Karimwassef,
What do think about these instead of a power head setup..

http://www.hotwoods.com/iceeater.htm

Wow...

I don't think that's reef safe but wow!

It's basically one giant propeller pump made of steel.

Hard to compare since the flow is measure in lbs instead of gph. It's also AC, so speed control is more complex.

 

[JamesHolt]

It says you can use it in salt water..
For speed control you would just need a VFD to run it off of..(Single Phase of course)
But I guess between the cost of the "pump" and the VFD, and a Micro-PLC,,you would probably be about the same cost-wise.. Also it isnt reversable so,, theres another problem..
Would make a hell of a powerhead though...lol....talk about cleaning the gunk out of a tank

 

[sculpin2]

In a somewhat related note, I'm in the process of building a sumpless 40B tank with reversing bulk circular flow. The basis of the system is two banks of oppositely pointed powerheads (one RW-8 + 1-2 others per side) that are switched on and off by timer to emulate tides (plus waves). Additional baffles were added to the viewing portion of the tank to encourage circular flow. I plan on filling the space behind the baffles with live rock debris as a pseudo refugium. The flow pattern will be: clockwise 4 hours (all right driving pumps on), nadir 2 hours (both small opposing pumps on), counter clockwise 4 hours (all left driving pumps on), nadir 2 hours (small opposing pumps on), and repeat. I may add a couple of additional small pumps for the nadir portion. I'm mostly done with the tank build at this point and am working on the hood/stand.

Attaching egg crate. Weldon #4 worked nicely.

Front baffles. One slipped during gluing, thus the messy silicone job.

In tank "sump" with directional powerheads.

Display area.

Top down.

Under skimmer pumps.

I am hoping to have water in it in a week or two and am looking forward to seeing if the concept actually works.

Hope this is relevant!

Mike

 

[dkeller_nc]

Karim - I didn't read through the whole thread (bit late for that tonight), but did read through the first 3 pages and the last 2, so I think I understand what you're trying to accomplish.

And there's a way to do it without pumps. And, a very long time ago, I saw it in action. Essentially, you install the "U" shaped channel as you've illustrated in the back of the tank, but the channel is open at the top, and is taller than the tank. In it, a large paddle is installed that forms a fairly close seal to the sidewalls of the channel. This paddle is actuated with a variable-speed electric motor and a cam. The cam bears on the top of the paddle (above the paddle's pivot), until it goes far enough to slip out, whereupon the paddle returns by spring force.

What this does is move a very large amount of water en masse, raising the water level in front of the paddle by 5 or 6 inches. This surge travels down the channel, through the diffuser and into the tank. The spring return of the paddle causes a surge in the opposite direction.

My memory of this is fuzzy; I saw it at an engineering department at a University some 30 years ago. But the water movement in this tank was a very close model of the surge that occurs on a reef crest, and IIRC, that was what its intended purpose was.

 

[ericarenee]

Karim - I didn't read through the whole thread (bit late for that tonight), but did read through the first 3 pages and the last 2, so I think I understand what you're trying to accomplish.

And there's a way to do it without pumps. And, a very long time ago, I saw it in action. Essentially, you install the "U" shaped channel as you've illustrated in the back of the tank, but the channel is open at the top, and is taller than the tank. In it, a large paddle is installed that forms a fairly close seal to the sidewalls of the channel. This paddle is actuated with a variable-speed electric motor and a cam. The cam bears on the top of the paddle (above the paddle's pivot), until it goes far enough to slip out, whereupon the paddle returns by spring force.

What this does is move a very large amount of water en masse, raising the water level in front of the paddle by 5 or 6 inches. This surge travels down the channel, through the diffuser and into the tank. The spring return of the paddle causes a surge in the opposite direction.

My memory of this is fuzzy; I saw it at an engineering department at a University some 30 years ago. But the water movement in this tank was a very close model of the surge that occurs on a reef crest, and IIRC, that was what its intended purpose was.

This is very similar to what i Remember from Newport Aquarium Wave TANK....
Thou i was not ALLOWED BEHIND THE SCENES (BOOHOOO) to see how they done it all.. I know there was baffles in each end...

You are in the same kinda Thinking as this thread has been....

Nice work on your tank. If you have a build thread please post ..

Erica Renee.. The Geeky CHIC With lots of power tools..:wavehand:

 

[karimwassef]

In a somewhat related note, I'm in the process of building a sumpless 40B tank with reversing bulk circular flow. The basis of the system is two banks of oppositely pointed powerheads (one RW-8 + 1-2 others per side) that are switched on and off by timer to emulate tides (plus waves). Additional baffles were added to the viewing portion of the tank to encourage circular flow. I plan on filling the space behind the baffles with live rock debris as a pseudo refugium. The flow pattern will be: clockwise 4 hours (all right driving pumps on), nadir 2 hours (both small opposing pumps on), counter clockwise 4 hours (all left driving pumps on), nadir 2 hours (small opposing pumps on), and repeat. I may add a couple of additional small pumps for the nadir portion. I'm mostly done with the tank build at this point and am working on the hood/stand.

Attaching egg crate. Weldon #4 worked nicely.

Front baffles. One slipped during gluing, thus the messy silicone job.

In tank "sump" with directional powerheads.

Display area.

Top down.

Under skimmer pumps.

I am hoping to have water in it in a week or two and am looking forward to seeing if the concept actually works.

Hope this is relevant!

Mike

Wow, Mike! Hardcore. Where have you been?

Looks like you're right there with where I was going with some differences. I wasn't willing to put baffles in the DT. So that's what I mean by hardcore. Are you planning on covering it up?

Based on the baffle locations and shapes, it looks like you're planning to direct the flow so that it forms two loops, one on each half tank. Is that right or did I misunderstand?

You're also running the "sump" back as an open top. I was thinking of sealing mine to create a strong pull from the opposite side, rather than letting the surface levels to fluctuate in relation to the pressure changes. Also the output in mine is sealed and baffled to stop the propellers forming local loops. It's also straight lined under the water level to direct any surface action back into the forward direction. It's like a "top baffle".

I think those are all nice to have but you've got the crux of the concept. You can synchronize those RWs and even try shorter pulses to see the flow pattern that results.

When are you going to be up and running? I was worried about the expense of making a model that I wasn't going to use... And you're doing most of it. What good luck to learn from your build!

Welcome!