Large Airpump Driver Skimmer

[areze]

I had read in another thread an idea that seemed solid.

take the overflowtube, go straight down, and put a T, straight through to a valve; close the valve till the water backs up. hopefully then only water exits into the skimmer through the valve, and the excess water and air exits the T outlet. you can also then control the water flow to the skimmer with a detour for the excess.

Id assume some small bubbles might get through the valve still; but hopefully not enough to be of any consequence.

 

[areze]

heres a drawing, close the valve till water comes out the overflow. hopefully then the valve is letting water through at the rate that the waters coming, not including air volume.

then close the valve more from there to tune the GPH to the skimmer.

 

[zapata41]

just wanted to show a few pics of the beastly skimmer in action

cup. 6" dia 6" tall

full shot, note it stands over 6' tall

bubbles in the bas of the neck

bubbles at the top of the neck 14" from base of neck to bottom of collection cup. neck is 4" dia

i am currently bleeding off 7lpm of air from my 65lpm air pump that is driving 2 - 9" swetwater fine pore diffusers that are under about 4-5' of water

enjoy

Tim

 

[areze]

why are you bleeding off the extra air? to underpower the stones and get finer bubbles? or something else?

 

[zapata41]

because there is simply too much air going into the skimmer. if i dont bleed off any air then i can shoot the bubbles to the roof, and with max air i get bubble bombardmanet, causing large bubbles to rise

Tim

 

[areze]

ah ok. Im looking at the next model down, (the 24 I think it was), for a much smaller skimmer than your monster. going to use 3 6" stones though, hopefully the underdriven stones will help keep the bubble size smaller.

really curious to see what those super fine pore stones would be like, but at 100$ a stone Im not going to find out

 

[zapata41]

also the super fine stone need 50psi to start working, ouch, that a big air pump there, or just run them off a O2 tank, lol very expensive

Tim

 

[areze]

yeah I saw that, figure some air must come out at low PSI. but still, I have no clue what youd use to get a steady 50psi of air at 60lit/min or so. air compressors can get the 50psi, but they dont pump 60lit/min I dont think, and they are very loud to boot.

 

[zapata41]

yeah i think those are more for low volume high pressure apps. where you would only run a few lpm through the diffuser, but at 100-500 micron pore size, i but the dont even makes bubbles, just pure thick foam like shaving cream style

Tim

 

[CaptiveReef]

DIY Skimmer

DIY Skimmer

Some nice skimmers!!!! Here is my DIY counter current skimmer, I can build one in an hour.

CaptiveReef

 

[Large Polyp Dave]

i've been looking at a bunch of threads this morning about airpump skimmers...

why are all airpump/airstone skimmers always so tall?


i understand that NW skimmers (like deltec/h&s/Bk/ER) NEED to be short because of back pressure on the venturi, but do airstone skimmers need to be so tall? or are people just making them tall because it increases skimmer efficiency?

would a short airstone skimmer run as well as a NW skimmer of equivalent height?

 

[tsalter]

They usually don't work if they are short. there is not enough water pressure on the stones to create small enough bubbles i believe. Some people on reeffrontiers tried to retrofit into normal skimmers and I think it just boiled the foam out of the skimmer.

Thats why I made mine that big.

 

[DrBDC]

CC skimmers need to be so tall because the whole concept of the bubble sticking to the crud is directly proportional to how long the bubble is in contact with the water before it gets to the surface. This concept applies to all skimmers. Even the needlewheel and Venturi would benefit somewhat from this as well. Think about how long it takes a bubble to rise in water. If it is taller it takes longer. And if there is a current flowing down, it will take longer yet. Really all the other types of skimmers were designed to get that same effect in a shorter more compact design. The best one would be sitting outside the house and strapped to the chimney and going 20+ feet high but you would be on the roof to clean the neck and collection cup! :lol:

 

[CaptiveReef]

Re: DIY Skimmer

Re: DIY Skimmer

<a href=showthread.php?s=&postid=6218993#post6218993 target=_blank>Originally posted</a> by CaptiveReef
Some nice skimmers!!!! Here is my DIY counter current skimmer, I can build one in an hour.

CaptiveReef

 

[BeanAnimal]

Captive can we get some details. Airpump size etc.

 

[tinygiants]

<a href=showthread.php?s=&postid=6411220#post6411220 target=_blank>Originally posted</a> by Large Polyp Dave
i've been looking at a bunch of threads this morning about airpump skimmers...

why are all airpump/airstone skimmers always so tall?


i understand that NW skimmers (like deltec/h&s/Bk/ER) NEED to be short because of back pressure on the venturi, but do airstone skimmers need to be so tall? or are people just making them tall because it increases skimmer efficiency?

would a short airstone skimmer run as well as a NW skimmer of equivalent height?

Assuming all other variables are the same yes. The only differnce in NW, becket, and airstone is the air injection method.

YUou must also consider the volume of air being injected.

Depending on the quality of the stones, bubble size will be different. Smaller bubles are better. Can a stone give bubbles as small as a NW? My medium pore stones do not. I will test fine pore stones tomorrow.

The next variable to consider is flow rate. NW and becket are either recirculating with a seperate feed or the y are fed with the injection pump. In my case I would have to reciculate, cause the pump running the injector is to fast for my tanks needs.

CC does help in creating a lengthened bubble dwell. Even with my larger bubbles, CC caused 1.2 seconds more dwell time. I expect this effect to be increased with smaller bubbles.

All these new ways of making short skimmers are compromisees. No mater what method is used to inject air, nothing is gonna improve efficiency like contact time. The best way to date to achieve contact time is through skimmer height. Increasing body size does increase water contact time by virtue of the larger volume, but it does not increase the bubble contact time.

Dale

 

[skerrytank]

<a href=showthread.php?s=&postid=6417652#post6417652 target=_blank>Originally posted</a> by tinygiants
Assuming all other variables are the same yes. The only differnce in NW, becket, and airstone is the air injection method.

YUou must also consider the volume of air being injected.

Depending on the quality of the stones, bubble size will be different. Smaller bubles are better. Can a stone give bubbles as small as a NW? My medium pore stones do not. I will test fine pore stones tomorrow.

The next variable to consider is flow rate. NW and becket are either recirculating with a seperate feed or the y are fed with the injection pump. In my case I would have to reciculate, cause the pump running the injector is to fast for my tanks needs.

CC does help in creating a lengthened bubble dwell. Even with my larger bubbles, CC caused 1.2 seconds more dwell time. I expect this effect to be increased with smaller bubbles.

All these new ways of making short skimmers are compromisees. No mater what method is used to inject air, nothing is gonna improve efficiency like contact time. The best way to date to achieve contact time is through skimmer height. Increasing body size does increase water contact time by virtue of the larger volume, but it does not increase the bubble contact time.

Dale

I understand the theory around bubble contact time and that taller skimmers are better because of the increase in contact time they give. Relatively short fat recirculating skimmers like BK seem to fly in the face of that theory and still perform well.

Does any one have any technical reference to actual skimmer tests run that measure the comparative quantity and concentration of skimmate produced by different skimmers, vs the power consumed. Obviously what we are all driving to accomplish is maximizing waste removal and the weight of dry grams of skimmate waste removed per hour.

It appears short fat recirculating skimmers can be made to perform fairly well, even if it may be through brut force. We may find the compromise in the increased energy price paid for over coming the tall skimmer contact time advantage is necessarily the driving factor in skimmer design if quality comparative testing was done.

 

[tsalter]

o2manyfish I believe did a test on reeffrontiers.

Yeah I agree about the recircs overcomming the tallness issue. But I still believe the reason why the new round of airstone skimmers are taller is just because people where having a hard time making a short one that worked and most of the people who made them are not worried about fitting them under a stand. I imagine I could make a fine small and squat air stone skimmer with a large enough tube. just make a radial manifold at the bottom 6" airstones pointed out like spokes. it would have to be at least 16" dia pipe though.

Contact time is important more height usually equates to better contact time. but I think for me it is easier just to make it tall as there was no height constaints in my fishroom.

 

[4Texans]

<a href=showthread.php?s=&postid=6419269#post6419269 target=_blank>Originally posted</a> by skerrytank
Relatively short fat recirculating skimmers like BK seem to fly in the face of that theory and still perform well.
...
[/B]

I do not think they are flying in the face of that theory, I think they are performing as one would expect.

You could test two skimmers of the short fat design, that are alike with the exception height. That is they would have the same pumps etc., yet make one taller.

I think you will find that no matter what one does, the idea still holds true. (I believe that the idea is something like the following.)

That is that:
- The more water volume skimmed, the better.

- The more surface area involved with air/water contact, the better.

(Smaller bubbles would have more surface area for the same volume of air. I suspect that ideal would be where as much water and air as possible existed in the water air contact zone so long as the adsorbed material could be extracted, and the collecting action of the dynamic bubble surface could be maintained.)

- The longer that the air/water contact is maintained, the better.

- The better the foam removal the cleaner the effluent.

That is if the foam becomes too dense before it is removed it could collapse into flocs that would stay in the effluent rather than be collected as waste.

If height is limited, then one would simply need to improve the other factors.

 

[chrisT]

Sorry if I missed it, but where is the water intake on this skimmer? I cant tell from any of the pics.