How to build a 750 GPH AIr LIft?

[Heinrich]

Since this is pull not a push system you shouldn't worry that much about inlet pipe size. Your procent submergence will likely be between 93-95%
Look on e-bay for good deals on air compressors.
Your pumping low pressure so a large diaphragm compressor is a better idea.

Another cool thing is that with two airlifts you can use a cheap threeway air valve or solenoid to give you wave action, simply switching the output from one pump to the other and returning your water to two different sides of the tank. The "header tank simply needs to be split in two for this.
I was looking at designing an economic closed loop wave system using airlifts and it seems pretty easy to do. Look at the ATS systems that use bioballs to prevent air bubbles from getting into the main tank.

I think the 750g sound pretty conservative too, talking with people who use 6ft airlifts pumping more than 2000gph. The problem is meassuring the actual flow through those. Even a 4 ft airlift will give you waterflow equivalent to 1" pipe draining down ~18" or so.

I'd like to see someone build a wavemaker model of airlifts. Giving alternating current in the tank with almost no electricity cost.
I'd estimate you get about 1000gph with 1" pipes feeding airlifts. All that for about 35W of electricity.

I want to see how the project is going.
good luck
93! Heinrich

 

[piercho]

Shane: you have mail.

Heinrich: the project's going fine - on paper!
The dual pump system sounds fantastic but maybe for a future system. Right now I'm trying to combine a periodic air lift with a 5G RCSD. The RCSD would cycle an algae scrubber along with the on/off action of the air lift. As the RCSD builds head as it pushes water out, the air lift would turn on and be at full flow the moment before the RCSD vents, turning the air lift off. This all happens in a small tank in a closet immediately behind the main tank. My main concerns at the moment are too much foam in the scrubber tank, vent noise, and foam escaping the scrubber into the main tank.

I've seen the Eco-wheel method of using bio-balls to catch micro-bubbles.

Could you clarify me on the inlet pipe diameter issue? I was using the entire length of plumbing (inlet and outlet) to figure my head loss. Since my inlet plumbing was the longest with the most bends I was going to use very large pipe (1.5" and 2") for it. Are you saying that this isn't necessary? I should only figure outlet pipe plumbing resistance in the head loss? I must be misunderstanding you. Also, why do you say that a diaphram pump will work better for me than a linear piston pump like the Medo LA-45b? That pumps best operational range is from 1 to 2 psi, about where I need it. I'm not argueing here, I'm no kind of M.E., I'm just trying to understand.

As far as a finish date, none is set. The tank is progressing OK as it is (just a DSB with ocassional skimming and a little caulerpa) but it does need more gas exchange and better nutrient export. And I'm hoping that the Medo that I want will show up on eBay in the mean-time, too!

 

[Heinrich]

Well the dual airlift doesn't need two pumps, just ONE airpump. The output of the airpump is diverted between the two airlifts via two solenoids or a three way valve. That means a wave motion if the airlifts pump to different ends of the tank.

A few bioballs work very well to catch air bubbles and still let plankton through. Easy and inexpensive.

The medo are good but consume more electricity, there are other options, but the pumps I was researching at that head height 2psi wasn't a piston pump. Couldn't find it on the online catalog and don't want to do the research right now, nor do I have an aquatic-eco catalog handy.

RCSD would be something to play with. I was toying with the idea of tumbling gracillaria to grow it in a tank that is used for the airlifts, which acts as a bubble eliminator at the same time. Split so the flows can be diverted to two different sides.

It's still necessary to plumb inlet as big as possible but has a tiny amount less effect. Basically the water flows into the lower density area of the airlift. Pretty similar to running down into a chamber say 3/4s filled with water.
So its not quite as important as pushing dia on those pumps. They do very poorly on pushing against resistance. Go with as large dia as possible on both, inlet will have maybe a 25% less effect on friction. That's all.
In the meantime just throw an airstone in your tank to give circulation. They work well as airlifts too.

So good luck on the airpump, they have one there right now, see the DIY reply to adjusting your CC skimmer.
Have fun!
93! Heinrich

 

[piercho]

Aquaculture Supply Air Lifts

Aquaculture Supply Air Lifts

I have recieved 2 of the last (discontinued) AS air lifts, a 1" slip fitting lift and a 1.5" compression fitting lift. These were referenced by snailman, above. The 1" lift is described bellow.

The body is a 4" length of white s40 PVC pipe. At a cross-section at the pipe's middle, 8 holes are drilled at 45 degree intervals. I cannot determine the hole size, but they are fairly small, maybe 1/16". Over these holes a 1.5" length of slightly larger PVC is positioned and held in place by rigid silicone dams at the top and bottom. So, in between the two pipe sections there is and air space. This air space is penetrated by a 1/8" insertX(MPT?) fitting set in the middle of the outer pipe. So, air injected into the insert fitting flows into the air space between the pipes and out the holes drilled in the 1" pipe. Nothing fancy. No array of holes (well, a 1X8 array) like is shown in the Spotte book. The holes aren't drilled at any special angle, etc. To duplicate the lift would be a simple DIY project. The 1.5" lift has a 1/4" insert instead of a 1/8" insert.

I'm still shopping for an air pump that meets my desires. Yes, I'm watching eBay. We are getting into crunch time at work on my current project. Anyway, it may be a while before there is any more news from me on this subject. Good luck to those of you who are pursuing similar projects on your own and please post your results here on the DIY board.

 

[LiquidShaneo]

Have you decided which pump you are looking for? I've picked up a number of Medo's on EBay recently (two 502's and one 602) for a very inexpensive price. In reviewing EBay, there is an auction that's selling 4 vaccuum pumps (VP0625) that might work for your application depending on how much air you need to supply:

http://cgi.ebay.com/aw-cgi/eBayISAPI.dll?ViewItem&item=1697604701

http://www.medousa.com/pdf/linear.htm

http://www.medousa.com/pdf/Vp0625.pdf

Not sure if this is what you're looking for, but I thought I'd give you a heads up.

Shane

 

[piercho]

This pump: http://www.medousa.com/pdf/La-45b.pdf , is what I'm looking for. About $230, new, from koi-pond suppliers. I saw the AC0602 on eBay but dicked around and missed the bid. I'm considering just paying the $$$ for a new blower (La-45b): it's quieter and more power efficient than a similar compressor.

 

[Snailman]

I have a MEdo linear piston airpump and it has been running for years and I love it. Lots ot sell on eBay cheap so keep your eye out. Liquid Shaneo has bought a whole pile of them there real cheap. Maybe you could talk him out of one.

 

[piercho]

Believe it or not! I finally built and tested the thing on the bench.
Components:
- large green tube is a 5G RCSD. It hooks to the base of the lift (and tank outlet) by 1 1/4" hose. The vent hose is 3/4", as is the vent pipe (unseen) inside the RCSD.
- large black tube with a white cap at the top and bottom is a collection tank. This is where the lift outlet is debubbled. The RCSD vent and recylce are also here. The lift tube outlet is inside the collection tube, just at the water line. The white cap on top keeps water from blowing out, muffles the lift tube noise, and has a 3/4" air exhaust. The 2" elbow at the bottom of the collection pipe returns water to the tank.
- the white thing at the base of the lift pipe is a air injector.
- the test tank holds about 50G of water.
-the aluminum thing sitting higher than the outlet (1st picture) is medo 602 air pump.
Specifications:
Lift Pipe: ~4' X 1.5" ABS
Inlet/Outlet pipe: 2" ABS
Air Injection: 1.5 CFM (measured by displacement).
Performance:
900-1200 GPH

Average performance was right around 1000 GPH. You shold note that this lift has a lot of plumbing pipe length and bends (5!) that would not be present in a direct-drilled tank.

 

[piercho]

I've decided to use this system, but there ain't no way I'm having all those big slip fittings beneath the water line, so I've got a unified-body lift+RCSD about half built.

A couple of notes:
-Any kind of induced head (inlet screens, etc) REALLY cuts the performance.
-Tapping a fitting at the top of the inlet and outlet pipes, i was able to use a small venturi to suck out the air, and keep the air sucked out of the outlet pipe.
-This thing can be noisy. Rev 1 has a lot of designed-in dampening.

Another pic showing the return pipe and some cetail of the RDSD.

 

[wizsmaster]

are you still running this system, if, or if not ... why? if you don't mind

thanks,

marco

 

[JaredWaites]

Marco,

Your one of those bring the threads back from the dead guys huh?

lol it was from 02. Try to PM him, his last post was yesterday.

 

[piercho]

I discontinued its use when I moved the tank to a new house. The Lift/RCSD was constructed before uni-seals became available and I did not trust the silicone seals at the underwater joints after the tank move. I shut the whole tank down 8/1/07 to prepare for yet another house move. The present plan for a new tank does not include an RCSD/lift. I've found methods to get the gas exchange without the lift, and the surge/water motion can be efficiently achieved now with electronically controlled DC pumps, like theTunze Stream.

 

[wizsmaster]

Jared,

Not usually .. but i figured it was a great time to see how peoples views, and hands on operation over a longer period have changed, and what lessons they have learned ... what modifications, or improvements have come from it.
Are you running a coral propagation setup?

Howard,

I'm looking for a less expensive way to provide flow inside frag tanks & LR bins. I know that there are a few coral propagation operations that use air lift units to assist in their flow requirements ... I cannot remember whom of the top of my head though. Lost all of my bookmarks & notes a few months ago in a hdd crash.

Have you seen more recent write-ups, or commercially available airlifts for the aquarium hobby?

Thanks,

--marco

 

[bristle]

I think the worst part about them is the noise from the compressor and the salt creep. When the bubbles pop at the surface, they send little droplets EVERYWHERE. You'll find salt...well...everywhere.

 

[Cristina_j]

what does "RCSD/lift" stand for?

thanks,

cristina

 

[piercho]

RCSD: Reverse Carlson Surge Device. A vacuum surge that sucks water in when the surge device is triggered. It differs from most surge devices in that it neither creates bubbles or has moving parts. My lift had a 7 gallon RCSD that worked in parallel with a 1.5" X 4' lift, both on the same air source. As the RCSD vessel charged up (water was displaced out by air) the lift would flow faster and faster (increasing air pressure) until the RCSD fired, which shut off the lift for a few seconds (no air pressure) until the RCSD filled with water and the cycle started over again. With 2 Medo AC602 pumps charging it (as well as a 4" X 4' skimmer) it fired about every 30 seconds.

The downside was that the whole apparatus was fairly big, and the RCSD firing was pretty loud, even thow I vented it outside.