S
singularity
- 37
- 8
Hi,
I've seen a lot good said about these pumps and decided to go with them for my purposes.
One thing I kept hearing about is how quiet they are. I guess "compared to what", is the question, as well as perhaps "under what circumstances", would be another.
One thing I quickly discovered is that the air manifold on them leaks like a sieve. Not so much from the joints where the hose hooks up to the manifold, but all around the adjustable air valves. If any air is allowed to escape here, noise comes with it. The noise is from the dual diaphragms hammering back and forth in tandem at line frequency, and so it has the the capability of being disturbingly loud.
In addition, one method people seem to speak of to quiet their pumps is to suspend it by some shock absorbing cord or hang it by its own cord in order to ensure it doesn't transmit vibrations into whatever it's sitting on. This can and should probably be largely disregarded, because the first step must be minimize the noise it's creating at the point it creates it, stop the very source of the noise, and then worry about muffling what's left of it later. Essentially you don't put a band-aid over a knife wound without at least first pulling out the knife.
While I was playing around with it I quickly discovered that tilting it was a very bad idea. The "connecting rod" between the dual diaphragms is rectangular and housed between transformers in a gap that's too narrow to allow clearance for it to rotate, but that doesn't prevent it from trying!!!
What you have then is obviously the shaft grinding up on the sides of the transformer and that makes the pump very loud indeed. The only way I see to avoid that, is in keeping the pump level, such that the center of gravity on that shaft works to prevent it from rotating rather than the opposite.
If yours is making a hammering sound, you need to take it apart and center that shaft.
Now, back to the air leak issue. I didn't spend good money on all of this pumping power to have it leak anywhere, where it's doing no useful work for me, and instead works against me by alerting neighbors, for example. This is intolerable.
After some quick research I found a method that seemed to make a lot of sense, tested it out for myself, and it works like a charm.
Basically, you use a glass jar, which is very stiff and won't be inclined to vibration by the pump, thereby very effectively containing the noise from it inside the jar. The jar needn't be any larger than a typical Mason jar, but it could be as large as a pickle jar as well. Preferably you would have a jar with a plastic lid, instead of a thin metal one. Thin metal lids will be prone to rusting very rapidly, leaking, and not as completely effective at damping noise.
All of your hose inputs from the pump, and hose outputs to the airstones, need to go through the lid. So it helps to have a lid with a large enough area to accommodate them all.
I am using several little honey jars, slightly smaller than a Mason jar and maybe a bit wider, with a plastic lid. This gives me enough room to drill 2 holes that accommodate the 1/4" inputs from the pump, and at least four 3/8" outputs.
If you use good drill bits, start small with pilot bits and work your way up to the final size, you'll get very accurate holes. The accuracy helps in keeping them from getting too large, and too out of round, that would create a poor seal.
The nice thing here is that the hoses are much softer than the lid, and we can use this to squeeze the hoses through a smaller hole, creating an interference seal which doesn't leak at all. This to me is far superior to having to try relying on any kind of a sealant or glue.
I think it's probably imperative to have both outputs of the pump feeding into a single jar, just as they do into a manifold. This provides each diaphragm with required backpressure which should provide for optimal operation efficiency, as well as for maximum noise and vibration damping. The diaphragms work in tandem and so should be damped the same.
If you used separate jars for each output, then you will end up with unequal loading for each side of the pump which is going to create stress and with it additional noise, and reduced reliability. You don't want the fragile diaphragms to have to absorb such shock, instead you want their loads as balanced and as tame as possible to generate the least stress on them to begin with, and use the air compression/damping ability inside the jar to snuff out the rest, whilst containing whatever is left over.
If you have additional lids then you can make up additional combinations of outputs. What I intend to try next is a quarter inch feed from the first jar into a second jar that will have additional 3/8" outputs for more airstones and possibly another piggyback jar which will have a 1/4" compression loop with that same leaky air manifold that I previously removed, just in case I really need adjustability. This is obviously not as ideal since they do leak and will continue to, but noise from the diaphragms hammering back and forth at line frequency should be completely damped by then that it won't be a bother, and their slight leakage will just be a tradeoff in not having to have X^n lids with every conceivable hole pattern if I just need some air to evaporate chlorine out of a bucket of water or whatever. You always have to give something up for additional convenience.
Another nice component of this setup is it allows you to pre filter the air flow, rather than letting your airstones serve double duty as air filters and get clogged up in short order.
I've already tested water filtering in a bigger jar, like you would with a bong. It works but I think the water only so effective anyway and makes it louder than it needs to be. Ice in the jar to cool the airflow is a complete waste.. Having the ice agitated by the air stream and rattle against the side of the jar makes it louder than anything, and any cooling that takes place is rapidly lost to heat in the airline likely within the first few feet, such that by the time it hits the airstone it's at ambient temp and so it can't cool the bucket, but I tried it for science.
I think what I'll do then for filtering is cut a cheap open cell foam sponge into a disc shape such that it fits into the jar as a diaphragm, and feed both air hoses through it into the bottom of the jar. The outputs will sit above the sponge on the top side of the jar, so that the airflow is forced through the sponge and the crap will collect in the bottom. This will filter the very worst of it, without impeding airflow at all. The airstones are obviously much finer than the smallest particle sizes that the sponge will pass, so they will still get clogged but hopefully not as fast.
One has to realize that airstones getting clogged this way is a source of contamination and potential for infection. If all of the air going to them passes through this single checkpoint that we have easy access to, then we can treat it.
Speaking of checkvalves, I think it's also possible that the jar, so configured, could act as one.
Lastly, I would like to note that the airflow is no hotter than ambient, either, and so this metal encased diaphragm pump is a good design from that perspective.
When I first tested this pump it was far too loud to live with and I thought I wouldn't be able to use it, but the jar damper renders it inaudible from the next room and it's more likely that the sound of the bubbles will be louder.
I've seen a lot good said about these pumps and decided to go with them for my purposes.
One thing I kept hearing about is how quiet they are. I guess "compared to what", is the question, as well as perhaps "under what circumstances", would be another.
One thing I quickly discovered is that the air manifold on them leaks like a sieve. Not so much from the joints where the hose hooks up to the manifold, but all around the adjustable air valves. If any air is allowed to escape here, noise comes with it. The noise is from the dual diaphragms hammering back and forth in tandem at line frequency, and so it has the the capability of being disturbingly loud.
In addition, one method people seem to speak of to quiet their pumps is to suspend it by some shock absorbing cord or hang it by its own cord in order to ensure it doesn't transmit vibrations into whatever it's sitting on. This can and should probably be largely disregarded, because the first step must be minimize the noise it's creating at the point it creates it, stop the very source of the noise, and then worry about muffling what's left of it later. Essentially you don't put a band-aid over a knife wound without at least first pulling out the knife.
While I was playing around with it I quickly discovered that tilting it was a very bad idea. The "connecting rod" between the dual diaphragms is rectangular and housed between transformers in a gap that's too narrow to allow clearance for it to rotate, but that doesn't prevent it from trying!!!
What you have then is obviously the shaft grinding up on the sides of the transformer and that makes the pump very loud indeed. The only way I see to avoid that, is in keeping the pump level, such that the center of gravity on that shaft works to prevent it from rotating rather than the opposite.
If yours is making a hammering sound, you need to take it apart and center that shaft.
Now, back to the air leak issue. I didn't spend good money on all of this pumping power to have it leak anywhere, where it's doing no useful work for me, and instead works against me by alerting neighbors, for example. This is intolerable.
After some quick research I found a method that seemed to make a lot of sense, tested it out for myself, and it works like a charm.
Basically, you use a glass jar, which is very stiff and won't be inclined to vibration by the pump, thereby very effectively containing the noise from it inside the jar. The jar needn't be any larger than a typical Mason jar, but it could be as large as a pickle jar as well. Preferably you would have a jar with a plastic lid, instead of a thin metal one. Thin metal lids will be prone to rusting very rapidly, leaking, and not as completely effective at damping noise.
All of your hose inputs from the pump, and hose outputs to the airstones, need to go through the lid. So it helps to have a lid with a large enough area to accommodate them all.
I am using several little honey jars, slightly smaller than a Mason jar and maybe a bit wider, with a plastic lid. This gives me enough room to drill 2 holes that accommodate the 1/4" inputs from the pump, and at least four 3/8" outputs.
If you use good drill bits, start small with pilot bits and work your way up to the final size, you'll get very accurate holes. The accuracy helps in keeping them from getting too large, and too out of round, that would create a poor seal.
The nice thing here is that the hoses are much softer than the lid, and we can use this to squeeze the hoses through a smaller hole, creating an interference seal which doesn't leak at all. This to me is far superior to having to try relying on any kind of a sealant or glue.
I think it's probably imperative to have both outputs of the pump feeding into a single jar, just as they do into a manifold. This provides each diaphragm with required backpressure which should provide for optimal operation efficiency, as well as for maximum noise and vibration damping. The diaphragms work in tandem and so should be damped the same.
If you used separate jars for each output, then you will end up with unequal loading for each side of the pump which is going to create stress and with it additional noise, and reduced reliability. You don't want the fragile diaphragms to have to absorb such shock, instead you want their loads as balanced and as tame as possible to generate the least stress on them to begin with, and use the air compression/damping ability inside the jar to snuff out the rest, whilst containing whatever is left over.
If you have additional lids then you can make up additional combinations of outputs. What I intend to try next is a quarter inch feed from the first jar into a second jar that will have additional 3/8" outputs for more airstones and possibly another piggyback jar which will have a 1/4" compression loop with that same leaky air manifold that I previously removed, just in case I really need adjustability. This is obviously not as ideal since they do leak and will continue to, but noise from the diaphragms hammering back and forth at line frequency should be completely damped by then that it won't be a bother, and their slight leakage will just be a tradeoff in not having to have X^n lids with every conceivable hole pattern if I just need some air to evaporate chlorine out of a bucket of water or whatever. You always have to give something up for additional convenience.
Another nice component of this setup is it allows you to pre filter the air flow, rather than letting your airstones serve double duty as air filters and get clogged up in short order.
I've already tested water filtering in a bigger jar, like you would with a bong. It works but I think the water only so effective anyway and makes it louder than it needs to be. Ice in the jar to cool the airflow is a complete waste.. Having the ice agitated by the air stream and rattle against the side of the jar makes it louder than anything, and any cooling that takes place is rapidly lost to heat in the airline likely within the first few feet, such that by the time it hits the airstone it's at ambient temp and so it can't cool the bucket, but I tried it for science.
I think what I'll do then for filtering is cut a cheap open cell foam sponge into a disc shape such that it fits into the jar as a diaphragm, and feed both air hoses through it into the bottom of the jar. The outputs will sit above the sponge on the top side of the jar, so that the airflow is forced through the sponge and the crap will collect in the bottom. This will filter the very worst of it, without impeding airflow at all. The airstones are obviously much finer than the smallest particle sizes that the sponge will pass, so they will still get clogged but hopefully not as fast.
One has to realize that airstones getting clogged this way is a source of contamination and potential for infection. If all of the air going to them passes through this single checkpoint that we have easy access to, then we can treat it.
Speaking of checkvalves, I think it's also possible that the jar, so configured, could act as one.
Lastly, I would like to note that the airflow is no hotter than ambient, either, and so this metal encased diaphragm pump is a good design from that perspective.
When I first tested this pump it was far too loud to live with and I thought I wouldn't be able to use it, but the jar damper renders it inaudible from the next room and it's more likely that the sound of the bubbles will be louder.