Fridge Motor Air Pump

[Ca++]

Rounding up a lot of these ideas, I had another, that I then found existed. I may of even seen it before. A water pump in the tank (bldc so near silent) and a venturi to draw air into the water flow. I have found youtube vids, and amazon sell the venturi's for pennies. It's very much like the microbubble nozzles I can't get, but lower pressure, so you get bigger bubbles. What I have seen uses just a pipe as jetting, but I feel the air could be broke up more, with a gauze to break up the air, without adding a lot of resistance.
I will have to have a play, but this basic idea seems well covered

That seems to work well, just out the box. I don't know where it's from, but I'm interested

 

[420PyRoS]

Venturi systems work good.

Our Emergency bilge system was venturi based. If ingress of water was too much for normal pumps to keep up, we would open venturi lanes off the 10 Bar fire main that would create suction, AKA a venturi, to help remove water.

Air vaccum generators work the same way creating a vaccum from pressurized air or water flowing by.

Typical shape of fluid pressure venturi piping.


Also vaccum generators as well.




Not to mention the irrigation type you have shown. Water/air type.

 

[Ca++]

I gave it a run. 600a3 pump (4 meter head) and a small venturi around 1/4" to match. Results look promising. The air inlet has a spring 1way valve I had to remove, but then the little pump created enough low pressure, to pull in air, turning the water stream white. My bowl was churning around nicely, so still a perfectly good circulatory pump.

Using air stones in my tank, I have the water at atmospheric pressure, with the bubbles passing though. With this venturi and my pump, I have bubbles in water at maybe a 25% higher pressure. My mind is telling me any extra water pressure, will lead to a greater oxygen transfer. Just like putting bubbles into pop. Or conversely, how cavitation pulls gas from fluids. I was told a few posts back, that the swirly machine was giving good oxygenation, and couldn't think why. Maybe, this is it. It's mixing better, at increased pressures.

I have an oxygen test kit around. I will see what I can do

 

[JKD]

If you dissolve air into water under pressure it will generate micro-bubbles when released into atmospheric pressure. This process is used in Dissolved Air Flotation.

 

[Ca++]

The bends can be pretty traumatic, where divers must lower the pressure upon them slowly, or gasses form bubbles within bodily tissue. It's good to put a name to it.

My water had stood for weeks, and it, and my hands, smelt of algae setting this up. 6 hours later

I'm going to call it 12. It's not natural light, but it's past a reasonable 8, and carries pigments past 12. I will check again in the day, and report back if it's different enough. Temps in the goldilocks zone, perhaps 23c

This suggests 8 is all I should expect. Perhaps it is pressure getting me higher, which would be temporary. Which is fine, just as long as it gets delivered.

I have used the kit on tap, to see 8. My eyes calibrated

 

[Drop That Sound]

The Mysterious Discovery of ‘Dark Oxygen’ on the Ocean Floor

Researchers believe they have discovered oxygen being produced 4,000 meters below the sea surface, and think polymetallic nodules—the sought-after bounty of deep-sea miners—could be the source.

www.wired.com

Drop a couple of these bad boys in the res

 

[Ca++]

Is this the pump I'm waiting for?
(the next line is actually an ebay )

12V Brushless Double Head Diaphragm Vacuum Pump Diaphragm Pump PWM Speed Control​

The motor should be about silent, but the pumps are still a similar diaphragm. Each 6L, which is like a decent 3 outlet. It's not the cam I was thinking of though

Nice BB there, showing it's good kit. I'm not entirely sure what I'm looking at though.

Is the bearing sat in a black case, with another behind it? There is a gap between them, where maybe a cam lives. In the first pic, we see the pump heads are at different heights, so likely don't share a cam, like a mirrored pair might. I was hoping for apposing motion for noise cancellation. Is that gold bit really hitting that black plastic, and if so, what about the other side?

£30 used, from a lot of sellers. One claims they come from the states to china, in a stripped state. New ones are 5x the price.

I like that they tick over on 5v, and won't stall at that, if blocked. Obviously there is speed control involved (or not, if you don't want it), and with a total 12L capacity, I can unload that a lot with my 1-2L requirement.

 

[Rocket Soul]

Is this the pump I'm waiting for?
(the next line is actually an ebay )

12V Brushless Double Head Diaphragm Vacuum Pump Diaphragm Pump PWM Speed Control​

The motor should be about silent, but the pumps are still a similar diaphragm. Each 6L, which is like a decent 3 outlet. It's not the cam I was thinking of though

Nice BB there, showing it's good kit. I'm not entirely sure what I'm looking at though.

Is the bearing sat in a black case, with another behind it? There is a gap between them, where maybe a cam lives. In the first pic, we see the pump heads are at different heights, so likely don't share a cam, like a mirrored pair might. I was hoping for apposing motion for noise cancellation. Is that gold bit really hitting that black plastic, and if so, what about the other side?

£30 used, from a lot of sellers. One claims they come from the states to china, in a stripped state. New ones are 5x the price.

I like that they tick over on 5v, and won't stall at that, if blocked. Obviously there is speed control involved (or not, if you don't want it), and with a total 12L capacity, I can unload that a lot with my 1-2L requirement.

The price difference between used and new would have me somewhat suspicious. But 30 bob is a bargain so not much risk for test and assess.

 

[Ca++]

I think they might be from oxygen generators. The kind ill people have. They must be highly reliable (like life depends on it reliable) and owned by a responsible company. One who is maintaining them, and disposing of them.
The other option is air samplers. Where after contamination, it's best to change them.
There is a good sized supply of these on the used market.

I'm a bit reluctant, as it's a 12v 60w psu used. That's likely over 15w even at 5v. As much as pwm can do, it's still a 15w pulse. My 2L AC pump, for example, is 4w (rms, so 6w peaks). I may have to use such pwm, that the current is still rising in the winding, before the pulse ends. Which isn't unreasonable.
I don't have a lot of funds to play with. I can buy what I need, but have to watch what I waste.

Some of the cams used are pretty brutal in vac pump.

Not even any lube.

 

[Orange's Greenhouse]

Have you ever looked at the koi pond pumps (hailea v- series)? If they fail the owner looses thousands worth of fish. So they are reliable and quiet.

 

[Ca++]

I looked at the piston ones, but the pond suppliers are invested in noisy cheap designs. They sell the promise of less noise, again and again. For decades. They have no reason to up their game.

If they actually used a motor, instead of a vibrator, that should help. The piston one's use a motor, but just AC. Then proceed to shake something vigorously. To no net gain.

I'm looking for near silence. I have been using an app to listen to mine while I made tweaks. The lump is 3db quieter since I put a silencer on the diaphragm inlet. It's futile though. It's in an MDF box, I'm putting in another mdf box. Hung on elastic, as pictured in the random thread. I put carpet around, and it still had a 199hz resonance passing through walls.

My builds are quiet. No humming. An air pump shouldn't be my biggest problem. Though in this instance, it's the drywall cupboard it's in, being an absolute nightmare.

Having a motor as the power source will be an instant bonus, and if EC, then all the better. The screw compressor might then be king, but reciprocal parts are the norm. I need to slow some larger one's down. Halving somethings speed, means it carries 25% of the energy. Energy that is noise potential. These blue pumps have a metal washer as part of the diaphragm, but perhaps it can be changed.

 

[Orange's Greenhouse]

I have the Hailea V-10 for my fishtanks. It is silent in the sense that the air bubbles popping are louder than the pump. So the 35 dB the manufacturer claims is aligning well with reality. But you seem to have better insight into what "pond suppliers" make.

Pumps are not noisy because of the energy they use but because of vibrations. Using a heavy housing and decoupling reduces that noise.

 

[Ca++]

Our pumps are vibrators, with the armature attached to the diaphragm. The power consumption is therefore used directly to make vibration. These are not power efficient designs, so I would hope to use less power replacing them. Seeing that 60w makes me think of motor poling noise. As it moves between sizable permanent magnets. The cheaper smaller pumps use brushed motors though. Offering very little life expectancy. I'm perhaps still looking for what I need.

I have been looking at panel deadening material. Like bits of lead, to give the pump casing a bit of weight in the right places. I can't say just how loud it is, as my app is scaled entirely backwards. It only serves for comparative measurements. The bubbles are louder, but that is just hissing where the ear is sensitive. The bubbles make no bass at the tank, as that's dampened out. The pump makes the bass, that seems quieter, but carries through the fabric of the building. This drywall cupboard is really something though. You could probably hear the footsteps of spiders on it. I put in a shelf to work on, and had to put foam between the shelf and it's support. Just so I could put things down quietly.


The Hailea pumps do well in group tests. As do the little Tetra one's with a spider like appearance. Neither lasted me though. Neither will fit in the box I just made either lol

 

[Ca++]

Tried the small Hailea today. ACO 9601. The 2w 3.2L seemed promising beside the 4w 2L rating of the AP2 I use. It just can't get near the output though. The feet are great on it, and it's tone improved by the use of an internal chamber. Like I use an external one, but while the 2L bottle is like 100%, the Hailea is challenged for space, so maybe 20% quieter. Just weak though. I'm going to use the AP2 and maybe a variac. I have built a second box, for the box and bottle to go in now. Also turned the pump within it's box, and done a few laps with silicone tube before exiting. I may get some pics up later.

 

[Ca++]

Some time later..
Some of you may of seen this already (edit: like a post earlier..)

No vibration, no pulsation at the tank, but the bit of noise between the two, resonated in the drywall cupboard. Sound wave, upon wave, building up, into a sound tsunami, knocking through the wall.

Then I had a breakthrough (not the wall breaking, it was a brainwave)

It's all about the little elbow in the corner. Without it, the pressure waves caused by the pumps piston like action, travel easily down the pipe. Now, with this elbows restriction, The peak of the pulse stretches the silicone hose a little, then as the pressure drops, the hose contracts again. Releasing the stored energy. The difference was drastic. But I went with a bit more air volume, for greater elasticity

About 2 meters in there now. The chugging is about gone, but I will keep the 2L arrester. it gives 100% smooth flow. I could still hear the 50hz AC mains though. So..

I can hear it, if I put my ear on it. Or the hose by my ear.

That will do.

 

[Ca++]

Something really strange about plugging your pump in, and hearing nothing in a quiet room. It's only when the bubbles break the surface, that you know it's working. Even in my problem cupboard, I have not needed to hang that thing. Silent at a few inchs away, isn't a misuse of the word.

It's beyond my expectations. I think anyone wanting to do something similar, should try just a stock pump, with the external bottle, both together in a single box. An old speaker might be useful.

Don't do the youtube tricks of stuffing your pump with wadding. It's a fire risk, and dampens the pumps movement, which slows the flow. It will create micro plastics, that may damage the pump seals or block your airstone. It's not a good idea, and the pumps pneumatic hammering will still reach the tank/buckets