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View Full Version : Using airpump as an air lift pump?



foodchain
11-03-2011, 09:50 AM
I have had 3 large pumps burn out on me in the last 6 months. This is getting expensive fast as these pumps are pushing 2" lines.
So I am looking for alternatives. And had an idea. When I was young, I had an undergravel filter, with a riser tube and an airstone. The airstone, confined in the tube pushed the water out the top of the tube when turned on. There you have charcoal attachments, etc. Through observation and trial and air I learned that smaller bubbles moved more water than big ones. Now the concept of large amounts of water being moved UP by the lifting power of the air by displacing the water intrigues me a little. I would THINK...don't know yet, this is where you all come in....that you should be able to lift water this way for your growbeds, etc. AND have the water oxygenated at same time. So my math is a little rusty, but this is similar to the differential pressure equations I used to run...and for the life of me I can't connect the dots here. But I have run some basic hands on tests. With one air stone, in a 325 gallon biodeisel tank, inside a 3/4 inch PVC, I can raise the water roughly 4 inches over the surface. This was just the little blue cylinder shaped stones. Nothing fancy. However it got me thinking. One atmosphere is 32 feet, so as long as I am not lifting more than 32 ft, which isn't going to happen I think this may have some use. But I am missing some critical pieces here. If you replaced the single stone with a bubble wall, you would get more volume of air, in smaller bubbles off the same sized air pump. Smaller bubbles are key, as they move more air. As air is compressable, I don't think this would work in a high pressure setup, but I do believe it has low pressure, high volume applications in a vertical setup, of course as air goes up. Is my logic right, or did I burn out a fuse somewhere and need to think in a different direction? Thoughts, opinions, etc welcome.

cookie
11-04-2011, 09:04 AM
It might work to move water out of the tank but at what flow rate? If you are burning up pumps like that maybe check to see if you are running high head pressure. That kills even the best pumps early.

Maybe check into a regenerative blower to push a bunch of air into a lift pipes like that then if your grow bed surface level is level with FT a tube connecting them should flow it back if you are running rafts. If you are trying to get it way up to a gravel bed I don't think there would be that much luck but that is a guess.

foodchain
11-04-2011, 09:20 AM
Very good idea on that. The regenerative blowers I have seen are very expensive though. Unfortunately the water pumps are cheaper. I am not at the house, so I can't check the pump's name, etc but I think it was rated at 57 or 58 ft head pressure, and my heighest bed is 6ft? Maybe? I think...I have to look at this more, but I think they are getting burned up by either running at 1/2 phase I think it's called? Basically not enough power is getting to them is what an electrictian told me, and it makes them work harder. Moving the water down/out isn't a problem. Via grade and gravity I can move water anywhere down hill I need to. It's the getting back part I have problems with. Now with that said I have learned that I can use a smaller pump and pump straight up to the tallest point, then using a larger one through manifolds distributing in multiple beds. So by going to the highest point, then allowing gravity to pull it down through a manifold saves money in both size of pump, but also electricity...in theory. I haven't hooked a voltmeter to it to monitor usage probably should. I think the problem comes in the diameter of the pipe. Smaller pipe would have more pressure from air bubbles to lift water up. If I use a smaller pipe and/or more air and smaller bubbles if possible I think I should be able to increase lifting force. But that's the problem....blower I have seen are super expensive, don't know how to make smaller bubbles....this leaves me using smaller pipe. BUT if I go any smaller I am not sure it will move enough water to complete the ebb and flow. It's circle of trouble here I can't seem to break.

cookie
11-04-2011, 09:39 AM
Voltage drop? I doubt you are running 3 phase pumps and single phasing them. They would burnout much faster then that.

If its voltage dropping from to long a wire run can you pull new bigger wire? The amount of air needed to really move as much water as a pump might take more juice then the pump takes if I am thinking right. Plus the amount of small tubes it might get out of hand.

Can you switch to a smaller pump by a wee bit and run less amps?

What is amperage of the pump and wire size plus length of the wire run?

foodchain
11-04-2011, 09:47 AM
Sorry, I am not an electrician. I know fish breeding/aquaculture. Could be voltage drop, it is a lot of wiring involved. I will have an electrician take a look at it, as I doubt I either know enough, or have the right tools. But I used to be an underwater welder, and I am familiar with voltage drop off over long distances of leads. And that I would guess is my best starting point. I am not familiar with a wee bit...heard the term, but can't place it....or maybe my memory is slipping. Humor me for a moment, and please explain.

cookie
11-04-2011, 11:15 AM
A wee bit would be going to the next smaller size pump to lessen the amp draw to keep the voltage up preventing motor burn out if that is the problem. Was every pump the same and lasted the same amount of time or did the first one last way longer? What does the tag on the motor say and how far from the panel is it would be a decent start to see if that is the problem as I assume residential 14 wiring in the run unless different. get some pics if you can

If the motors are all that is burned out the pumps should still be good so maybe you could stick new motors on them.

underwater welder? Welding pipe was hard enough for me just at the union school I could not imagine underwater. My cover passes were awesome and I got to the point I could do cover shc 80 in one pass with a gas torch but still have an ugly root pass with 1/8 6010. Thank goodness I was better and trouble shooting and fixing A/C problems as it made work easier.

foodchain
11-04-2011, 11:25 AM
Okay, I will see what I can do about pics when I get home. It won't be until late tonight at the earliest as I am working 2 full time jobs. BUT...I will do my best to get them to you.
All 3 pumps are the same. It is the motors that burned out. But I am not sure as to the WHY.
The first one ran for about 2 years, then pooped out with motor hot as hell. The second, went a couple of months later, and the 3rd a couple of weeks. I believe this is electrical. I am planning to tear down the garage and redo the wiring anyway as I am drawing too many amps as it is. I think, with it bein winter I will have to isolate systems and downsize to the bare bones till spring. Spend this time getting set up/rewired and hit the ground running.
UW Welding isn't hard...the problem is the welds are brittle as the water flash cools the bead VERY quickly. But DC current is awesome to see travel up and down the inside of your dive helmet as a little blue lightening bolt...very close to the eyes though....not a whole lot of room in there. DO NOT get between the arc and the ground clamp. Salt water conducts electricity VERY well. And as everything is video taped from the top of your helmet, and everyone on deck can hear your coms....they know when you crossed in front of ground. Only do that a couple of times before you remember. Kinda like smashing thumb with hammer...you learn quick. Thanks for the input. I don't know how to post pics, so I will email them too you if you PM me your email.

cookie
11-04-2011, 11:55 AM
With the first pump lasting a long time you might have higher head from sludge buildup in the system piping or maybe poor electrical connection at an outlet,or other problems then the wire run. Testing amp draw would have helped narrow this down. I like to test the amp draw and note it in the manual or diagram in the control panel so another tech will have that info later to compare a motor they might suspect of having troubles.

I would really check to make sure the piping coming out of the pump is free and clear with the first pump lasting a while then the next 2 dying faster and faster but I never like to rule out electrical as most problems are. Did you notice decreased flow over the first two years?

To post pics you could upload them to a photobucket type account and use a link that you paste into the post that will put the pic in automatically.

Double check your outlets and make sure they are quality ones as you might get proper voltage until load is applied,you want to get good outlets not the 50 cent ones and use the screws to hold the wire down.

Can you get replacement motors for the pumps? That might save money on replacement costs.

That would be crazy to see lighting in a dive helmet! I saw lighting go over my arm once from a breaker that had some crap leak on it and it found ground over my arm sweat to the edge of the panel but I was sweaty enough the outside of my arm let the 277 fly over it only burning off some hair.

foodchain
11-04-2011, 12:05 PM
You got lucky.
These are 220 pumps I think? I don't know AC well....showing my 4th point of contact here....the 3 prong plug, like a clothes drier or home welder. Whatever the cause is, it made the pump motors work harder, hence the heat in my opinion. I did find a fish in the first one...some how got passed screens and pulled in far enough I didn't detect it for a while. Once removed though, that first pump never worked quite as good. Assuming this damaged it, like dead heading. But that wouldn't explain the other two. Unless the dead heading caused stress on the motor, which in turn caused a heavier draw on the power grid, heating up the connections/insulation along the way. Would this cause a phase issue or partial connection then? If so, I may have a fire hazard. UH OH. Now you got me thinking.

cookie
11-04-2011, 01:35 PM
I did mostly industrial work but if the legs are imbalanced with voltage IE 105 on one then 145 on the other that would cause it to heat up.

You sure they are 220 pumps? http://electricalsafety.lbl.gov/assets/ ... ations.pdf (http://electricalsafety.lbl.gov/assets/docs/NEMAPlugReceptacleConfigurations.pdf) what plug does it match?

With three phase I saw lots of single phase damage with defective contactors but I I assume by now you have checked and cleaned out all the piping and intakes.

Without a meter and ammeter to try to troubleshoot this gets hard. Its really a good investment to have one as just using it to trouble shoot stuff can save on having someone come out to do it.

foodchain
11-08-2011, 08:08 AM
It's fish in the pumps. Whatever screens you think you have....don't rely on one. Solids getting caught in pumps will burn them up. Regardless if it's a stick, rock, or fish. Damn lot of money to have wasted on such a simple concept. Hate it when the obvious kicks my *ss.