Bored! So lets design a Skimmer!

[mojoreef]

Ok so if you look at this one. I thought if we have a square box base, then take a acrylic tube (or large pvc) and cut it in half, putting half on one side and half on the other we could make a kind of revolving chamber as the mixing chamber. In between these two halves we would glue an acrylic flat sheet with holes drilled in it as a kind of bubble plate (so inbetween the red lines above) then do the same on the bottom but with smaller holes to keep the buubles count low below it (better for the intake of the recirc so the pump doesnt cavitate). You could build this section so it could be simply taken out for cleaning when that time arisies. I would say for the feed pump it should dump water above this mixing chamber, the water will be drawn down as the out flow of water would be below the mixing chamber.

The effect of that is that all raw water should have to go through our mixing chamber in order to leave the skimmmer, so output of the feed pump somewhere close to where you have drawn it. So for another step back, their are two main form and thus two main areas we are going to deal with total organic compounds. One area is going to be the mixing chamber to break down molecules and protien chains mechanically, so the tough ones. Now their are protiens and similar that are drawn to the air water interface, some like to jump right in and some like to have their tail in the air and the balance out. These protiens and similar take up location in the areas between the bubbles, where you see that ammount of water their. So if we capture them in the rising and accumulating foam column its an added bonus, this also makes a good entry point for those that like to use bacterial dosing bio pellets, the bacterial flock/biofilm that forms on the pellets can be shaken out of their reactor directly in to the feed pump, you could actually use the feed pump for the reactor as the feed pump for the skimmer if you wanted.

ok so back on track. What we need at this point I think is to find which kind of recirc pump we should go with, does anyone have the ability or equipment needed to put together a rough form of this, even just something to test a few different kinds of pumps on??


MOjo

 

[Sasquatch]

so? raw water is entering above this? where is the exit?

 

[mojoreef]

Same location you drew on your last one. my drawing is a side view right?


Mojo

 

[Sasquatch]

ah, ok, back to the lab lol, coming together a bit better in my head, need a redraw

 

[Guerry]

lets get some measurements together and I can build if you can think it LOL ?s to answer what size box , tube size to be split for recric area are we going to use becket ,needlewheel,injector or other

 

[TheKraken]

I had the opportunity to talk with Mike at the picnic. The more we talk the less i understand about skimming but I still feel like I have a front row seat!

I say the post in the morning and looked at the cross-section.... Where have I seen an oval of just about that size...

Turns out I have all sorts of examples on the floor at work as "square plastic recycle bin". Should reduce cost of fab.

On a seriouc note I have concerns over bubble plates and other mesh inserts as they tend to grow stuff and foul. Does Ozone/UV slow the accumulation?

 

[mojoreef]

The more we talk the less i understand about skimming but I still feel like I have a front row seat!

LOL thanks!!

On a seriouc note I have concerns over bubble plates and other mesh inserts as they tend to grow stuff and foul. Does Ozone/UV slow the accumulation?

So do I, but I wanted to rule it out first. What I was thinking when the plates came up is a way of seperating the big flow and turbulance in the mixing chamber and the section above, I dont want to screw up that section above with the violence below, so still wide open on that one. Ozone and uv are different but similar in others. Ozone if to high will actually distroy air bubbles so you need to maintain the proper levels. What it does for you is that it tends to break organics down into smaller, more hydrophilic pieces, and such pieces often are more readily biodegraded than larger pieces, so a good begining of the degradation process. UV you can look at it somewhat similar on the pro side, on the con side I have not noticed the over creation of oxidation.

mojo

 

[TheKraken]

At the Picnic I discussed a recirculating Beckett like thingy and Mike said "write it up!"

Note: This has nothing to do with anything else on this tread...

In watching my skimmer work for a few hours, The water and foam are injected at point A and start to circulate the chamber. In section B I have a sharp boundary of water (below, ready to exit skimmer) on foam (above, extracting proteins like mad right at the interface). I am really happy with the chemistry at B. Really small bubbles get carried with the current and exit as micro bubbles. In section C to some degree and certainty D the bubbles are expanding (atmospheric force?) and collapsing (combining) and otherwise misbehaving. At point D my skimmer burps as I get a nice head of foam as expected but the bubbles collapsing at the neck turn into large bubbles and push up the neck. When the air escapes the foam head drops until the next burp.

How do I maximize the performance of micro bubbles in region B?

For illustration I have drawn a tradition Beckett foam jet with the foam on top and a narrow connecting tube. I assume the tube has enough velocity that everything is blown along like a freight train. Higher pressure yields smaller bubbles an more flow clears the chamber quicker.

What if the post Beckett tube was widened to the point that the velocity decreases to the point that buoyancy would be observed. At the bottom of the chamber (H) the smallest of the bubbles would be carried with the flow and exit as micro bubbles. Bigger bubbles would collect at region G and hopefully be recycled by the Beckett to make another trip. The big bubbles are useless as they have a small surface for a large area and just make a mess.

In this design a collection vessel would be required for de-mixing the micro bubbles are removing the foam scum. This would not be a recirculating design as in recirculating the water. Rather we are modulating the velocity of the injector to adjust bubble production.

Please tell me where I went wrong

 

[TheKraken]

Bigger image for ease of viewing. Mod surgery?

 

[TheKraken]

Here is a movie of a prototype commercial skimmer that is just about the exact opposite of the above concept described above. It turns out that commercial waste water treatment cares a lot about separating fats, oils, and sludge from water. It seems like they embody the motto "if brute force does not work, you clearly did not use enough!"

Ozone Tech (Singapore) Pte Ltd.

 

[mojoreef]

At point D my skimmer burps as I get a nice head of foam as expected but the bubbles collapsing at the neck turn into large bubbles and push up the neck. When the air escapes the foam head drops until the next burp.

I have seen this happen from two different circumstances (thier could be more though) one is that you have an area (in your case) under the flange at the point where C flage connects to D tube, here bubbles might be nuilding as they have stayed in place and the skimmer is not perfectly level (which is impossible). The second is that you have reached a saturation point with in the B/C chamber and the bubbles are joining because of it. It might be worth a little test, take your air intake on the beckett and close it off to find the water level in the skimmer, mark that with a peice of tape, then let the air back in, then take another peek and do the math on what percentage air to water you have.

On the second concept I am a bit unsure of its overall use, I need a little more explaination...you know for the old and slow???


Mojo

 

[Sasquatch]

" At point D my skimmer burps as I get a nice head of foam as expected but the bubbles collapsing at the neck turn into large bubbles and push up the neck. When the air escapes the foam head drops until the next burp."

Ive found back pressure can do this, as the foam starts to climb its also clogging the neck, any restriction in the neck forces more water through the outflow (try putting your hand over the neck to seal it and you'll see.) so you have some surging going on raising and lowering of the water level,the burps can also happen in the pipe from the beckett head unit to the inlet area, I installed a small meshwheel recirc on the body, it ate all the burps and made a huge improvement

 

[Boomer]

OK, I listened to Mojo and just DIY this one.

 

[Guerry]

nice work Boomer, can you tell us more about the ins and outs of how your skimmer works

 

[Sasquatch]

nice work Boomer, can you tell us more about the ins and outs of how your skimmer works

its not a skimmer lol thats a mash separator for his still.

 

[TJL]

Hey Paul, that is a very cool link. Technically a little over my head but, understand enough to believe it solves some of your concerns/questions of fouling bubble plates and getting or adding more contact time to the reaction chamber. I really appreciate having you guys educate us all beyond Skimming 101

Cheers, Todd

 

[Peppie]

I to am grateful to you guys, for helping me better understand How a skimmer is to work.
All I knew before was I needed a HOB rated for double my water vol.
What I have gotten from this thread is. Tiny bubbles. Dwell time. % of air to water. All make a huge difference.
I have been trying to think of a way to keep those tiny bubble in the reaction chamber as long as possible with out having a 7' tall chamber.
I first thought about a Switch back design. Mixture travels up the chamber at a small angle, then switches direction, up another small angle, and so on. ( Kinda like a switch back road up a mountain.
I dont think it will work cause the tiny bubbles would turn into big bubbles by the time they got to the top. Even if they didnt, cleaning the angled baffles would be another problem. Plus there would be a great lose of velocity in that chamber by the time the bubbles got to the top.

Plan B
What if you used a chamber shaped like an Auger Bit? Would the results be the same as plan A ???

As I usually do, I am thinking out side of the box. Sometimes it works. Most times it dont. lol But at least you guys got me thinking.

I am starting to think the Air stone may be the easiest, simplest, most effective way to go.

 

[Boomer]

Todd

Hey Paul, that is a very cool link. Technically a little over my head but

Try this one, it is much more simple.

http://www.angelfire.com/ri/rpatro/research/Bubble/patroetal.pdf.

 

[Guerry]

nice read there Boomer, wish I could unstand it a little better. I plan to start build on Mikes design this weekend so we can start testing

 

[Sasquatch]

nice read there Boomer, wish I could unstand it a little better. I plan to start build on Mikes design this weekend so we can start testing

Cool! I just finished modding mine to the information gathered so far, when the glues dried Ill see what happens, if there's an improvement I will build a new one