Note that it's possible to (mostly) hermetically-seal non-helium, air-exchanging breather holes of HDDs for use in submerged mineral oil applications. It's typically done by adhering a flexible membrane over the air port.
The Race to Seal Helium HDDs (2021)
111–120 of 138 posts
Re: The Race to Seal Helium HDDs (2021)
#112Earlier quoted context omitted.
vacuums tend to collapse on themselves, I think it might be more costly in structural elements to prevent that?
Thermoses have vacuum in the walls, and they are very thin, much thinner than a hard-drive case.
I think they do get designed specially for resisting the vacuum collapsing the walls, but you're right, it can probably be done!
Re: The Race to Seal Helium HDDs (2021)
#113If anyone has a helium drive you can check it's levels - S.M.A.R.T. ID 22 If you are bored I'd be interested to hear what level it's at on old drives. Like is it still 100% after a year? [edit] I assume the 100/64h means 100% maybe not [1] https://www.reddit.com/r/windows8/comments/11ndk0o/what_is_c... https://en.wikipedia.org/wiki/Self-Monitoring,_Analysis_and_... [1] https://www.reddit.com/r/DataHoarder/comments/wl…
I've got 3 drives at around 20K hours and all 3 are showing "100" in helium level.
Re: The Race to Seal Helium HDDs (2021)
#114I wanna be this guy when I grow up. Seriously, how realistic is it to get a job like this guy's? Open ended, no rules, just solving problems... Most days I'm fine with a boring specialized engineering career, but this one got to me...
Any career in fundamental research is more or less like that. From what I've seen personally, academics and government labs are the two biggest places you can find the most open ended roles. Each comes with their own caveats, of course.
Re: The Race to Seal Helium HDDs (2021)
#115An interesting side-story here is how the R&D here was sustained through three corporate acquisitions - from IBM to Hitachi GST to WD.
Re: The Race to Seal Helium HDDs (2021)
#116What would happen if you had a rigid structure that helium could permeate, but nothing larger could, and then filled it up with helium and waited? Would most of the helium exit, until it was balanced with just the partial pressure of helium in the atmosphere? That would be nearly a vacuum, wouldn't it?
I don't think so. Ignoring the fact that what you're describing sounds suspiciously like a Maxwell's demon, I think the equilibrium would be at a higher pressure because helium escaping against an overall pressure gradient would be doing work. In essence, at the boundary I think the rate at which helium escapes would not simply be proportional to the gradient created by the internal pressure and the exterior partial…
This relates to the difference between how a real gas and how an ideal gas behave in this scenario.
The difference in this situation will be very small in my opinion, broadly because the gas molecules in the atmosphere still have comparatively high mean free paths and therefore won’t interact with the “escaping” helium molecules.
Re: The Race to Seal Helium HDDs (2021)
#117What would happen if you had a rigid structure that helium could permeate, but nothing larger could, and then filled it up with helium and waited? Would most of the helium exit, until it was balanced with just the partial pressure of helium in the atmosphere? That would be nearly a vacuum, wouldn't it?
It would be a vacuum I guess, but generally not in the normal sense because this is the case with most metals. You don't really consider the interstitial space between the atoms in the crystal lattice a vacuum even though there is space for small atoms (He/H) to diffuse through.
The OP is imagining a device with a “hollow core” of atmospheric pressure helium surrounded by a solid and continuous membrane.
Since this hollow core would be much larger than the crystalline structures in a metal would this not therefore be a very weak comparison?
Re: The Race to Seal Helium HDDs (2021)
#118Earlier quoted context omitted.
One MRI machine uses about 2,000L of liquid He, which expands to around 1:770 in gaseous form. So roughly 1,540,000L of helium gas per machine.
MRI machines borked the MEMS accelerometers in iPhone due to helium contamination. I assume most smartphone sensors are now helium-tolerant.
Nope. They just added a warning so it's your fault if you get any helium atoms in your oscillator.
https://support.apple.com/guide/iphone/important-safety-info....
Re: The Race to Seal Helium HDDs (2021)
#119Earlier quoted context omitted.
Wouldn't be a fire risk because there's no oxygen available. But hydrogen is chemically reactive and over time it could corrode or weaken the materials inside the HDD.
That's not the main problem. The main problem is hydrogen is fucking painful to contain.
Not as painful as helium. Bigger atom but it leaks more.
Re: The Race to Seal Helium HDDs (2021)
#120Earlier quoted context omitted.
Pretty sure it would simply equalize to the external pressure. Consider it another way. If you have such a device with a vacuum inside, would it not pull in the external helium over time to reduce the vacuum?
> Pretty sure it would simply equalize to the external pressure. External partial pressure of helium which is extremely low. > Consider it another way. If you have such a device with a vacuum inside, would it not pull in the external helium over time to reduce the vacuum? It would, but only until the partial pressure of helium inside is equal to the partial pressure of helium outside (assuming the membrane is permeab…
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