Near-Silent Bellows Uses Water Flow And Magnetic Coupling

Fan noise is a contentious issue among the computer community. Some don’t notice it, others rage against it as an annoyance and distraction. Some turn to liquid cooling, while others look to passive solutions to eliminate the scourge. [Matt] of [DIY Perks] may have found a far more oddball solution, however.

The build is essentially a giant bellows, but the manner in which it operates is unlike anything we’ve seen previously. To shift the large pusher plate inside back and forth, [Matt] initially experimented with building his own linear motor out of coils and magnets. After that failed, he began to tinker with a system of moving a magnet back and forth through a tube with water pressure from a pump, which would then drive the pusher plate through magnetic coupling. This looked promising, but reversing the flow proved difficult. After building his own set of water valves to change the flow direction, the bellows began to work slowly, but with limited performance. Realizing the valves weren’t up to scratch, [Matt] rebuilt the system with 10 pumps, set up in two banks of 5. With the pumps hooked up in series, they supplied plenty of pressure to force the bellows back and forth. Reed switches were used to reverse the flow at either end to make the bellows run continuously.

In testing, the bellows compared well with a bank of four large case fans, though at 20 times the size. Suffice to say this is not exactly a compact solution. We look forward to seeing [Matt] do more with the bellows, with his intention being to use it as the primary cooling system for a computer. Of course, if this looks too complex, you could always consider a mineral oil setup instead. Video after the break.

38 thoughts on “Near-Silent Bellows Uses Water Flow And Magnetic Coupling

  1. I’m hoping to see the follow up video, where he starts noticing the water go through color changes as the magnet turns into a hollow shell, and eventual discovery of where all the iron and neodymium oxides precipitated.

      1. Distilled water will still make things rust – just needs a bit of dissolved air for that – which it will pick up eventually even if it was initially devoid (which it won’t be). Also the distilled water will be very happy to grab metal ions – lots of room for them to drop into – so any galvanic corrosion type mixed metal action can happen too.

        Won’t be all that quick but with flowing water for mechanical wear and the inevitably of oxygen diffusing into the water it will happen eventually. The question is how fast.
        Still way better to use distilled, perhaps with a little biocide and corrosion inhibitor than normal tap water, but it doesn’t mean it will never ever happen.

        1. It’s a race between the physical wear of the nickel/copper cladding as it moves back and forth, and the galvanics caused by the dissimilar metal fittings in the system. Not to mention the magnetic fields affect on that. Add one abrasive particle to accelerate the process. Plenty of entropy to feed on here.
          The magnetics of the pumps should pickup all the Feo2 until they seize. Wonder if the Nd2O3 will remain in suspension, or be deposited as well? Will it turn the water Aqua, or Pink? Or will it crystallize on surfaces for a nice dichroic effect? Or will it just be a boring blue grey sludge? Could be fun to watch!

  2. 10 water pumps, I wonder how much power this thing uses.

    The closest match in physical appearance appears to be a “QR30E pump”
    Input: DC 12V, 4.2W
    Max Head(lift height): 3M
    Max rated current: 350mA
    Qmax: 240 L/H

    Since 5 are active at a time, that should be 21W
    I suspect in terms of efficiency that five 3W (12V 0.25A) 20cm PC Case Cooling Fan 17.52CFM (29767 L/H) each would win hands down.

      1. Wins only if you can actually generate the force to produce the static pressure. In this implementation he needed 5 pumps in series just to get the thing to move: using just one pump stalls. Add any significant backpressure and either the pumps will stall out or the magnet will decouple.

    1. Really will depend on how well it can deal with static pressure, and set up. I would be rather surprised if any PC style fan could match this for pushing through high resistance – so with the extra extra dense fin count radiators it might well outperform them both in cooling and poweruse.

      I would be very surprised if any normal computer setup found this massive box beneficial on efficiency – but trying to cool a dual CPU and multi GPU type system or a whole rack it might – as for that heatload you need lots and lots of radiator and fans (and probably more pumps) – where this box I expect will push through a double or triple stack of high density rads (assuming the magnetic coupling is strong enough).

  3. While watching the video I was constantly asking myself why he went for that complicated setup with the magnets. Since he is using pumps anyway, why not make a spring loaded hydraulic actuator instead? That way he would only need one set of pumps to pump in one direction and the spring would push it back the other way.

  4. Obviously a completely ridiculous, inefficient and impractical way to move air, and even to get a SquareSpace sponsorship. But kudos to him for doing it, because I didn’t.

    What’s next? An oversized Roots blower? Actually not a stupid idea: no valves, only two moving parts, no sliding seals, arbitrarily low friction…

  5. I’m impressed by the determination here!

    After 15 years in my livingroom, I moved the PC (which by now is just a storage / compute server) into the basement. Wow! I had just taken the noise for granted, but now when I stand in just the right place in the basement I’m like “what is that roar?”

    I’m a huge fan of passive cooling. The Android TV that took over media player duties is passive. All our laptops are passive. Phones and tablets are passive. The Intel Celeron N4000 really impresses me — I never though Intel would reach this ARM-like level but it’s happened and people just take it for granted. My new N4000 is 50% faster than my 10-year-ago core 2 duo laptop, but it’s passively cooled and sips power. The old laptop made so much fan noise I could hear it across the house!

    The weird thing is, the reason we have so much fan noise these days is entirely bad software engineering, largely in websites (Javascript) and browsers. I remember when I noticed that my battery life was decreased by about 30% if I was logged into Slack all day! It’s infuriating that so many users don’t get any benefit at all out of the last 20 years of CPU development. The browser is still slow, it still burns your lap and deafens your ears, the battery is still brief. There’s no palpable improvement at all. You still sometimes see the computer struggle to render characters as fast as you are typing!!!

    So for me, I run the browser in the basement and view it over VNC. Way less work than inventing a new cooling system.

      1. You certainly can be right – but as motherboards tend to have less heat generating components on them now (more of its been put inside the CPU) if you take away all the heat from the CPU efficiently the motherboard will quite likely be alright with no air moving – all the air volume of the case to warm up, and the entire surface area of the case to radiate the heat of that warmed air.

        Wouldn’t really recommend it, it would be hard to do with standard components anyway – but it certainly can be done under very specific conditions (quite a few laptops are actually like that internally air only flows over the CPU/GPU heatsinks, which may or may not have some connection to the system RAM or other heat generators).

        These days the more likely thing to have issues with no moving air and lack of big heatsink are the high speed flash drives I would think – they might be remarkably energy efficient overall but the do run rather warm when pushed. (also don’t seem to have self preservation throttling as well sorted as the rest of the system – though that’s a very small sample size observation)

        1. Quite likely the power regulation components in your motherboard expect to see some airflow, so having no case ventilation whatsoever will cook the capacitors. Same thing for your graphics card – if you add a water block, you also have to add bigger heat sinks to the RAM and power regulator chips or else they’ll overheat.

          You don’t need to vent the air outside of the case, just have enough motion inside the case that you don’t develop hot spots.

Leave a Reply to turtle-z Cancel reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.