4 ms·

How would hydrogen work instead? Or is it not trustworthy enough if there's an oxygen leak inside and a spark occurs?

by cordite 11y ago

deleted 11y ago
[deleted]
woodman 11y ago
Hydrogen is much harder to contain. [0] [0] https://archive.org/details/cihm_81141 https://archive.org/details/cihm_81141
donatj 11y ago
Hah, and then hard drives crash AND burn. I'd think nitrogen would be a better option, my shop fills my tires with it, supposed to be easier to contain.
- woodman 11y ago
  "Usage of helium inside a hard drive helps to reduce the drag force acting on the spinning disk stack and lower the fluid flow forces affecting the disks and the heads. As a result, HDD makers can install up to seven platters into a standard drive and also use lower-power motors and mechanics. This reduces the power consumption of the HDDs."
  - donatj 11y ago
    Would nitrogen not? What about a vacuum then?
    - cataflam 11y ago
      Nitrogen is pretty close to air, which is already 80% nitrogen. The gain would be minimal. As for vacuum, it's harder to maintain, and wouldn't work anyway : https://news.ycombinator.com/item?id=11593997 https://news.ycombinator.com/item?id=11593997
    - b101010 11y ago
      "Disk drives depend on the head floating on a cushion of air, they are not designed to operate in a vacuum" https://en.wikipedia.org/wiki/Flying_height https://en.wikipedia.org/wiki/Flying_height
      - XorNot 11y ago
        I've always found that odd these days. Given that we're already not doing dumb magnetic manipulation anymore, is it not feasible to use a static magnetic field between the head and platter to the cushion the drive at all? The magnetic interaction with the platter would be presumably predictable, since it's the oscillation that's used to write the data.
    - gambiting 11y ago
      Considering that normal hard drives have regular in them, and regular air is over 78% nitrogen, I guess bumping it to 100% nitrogen wouldn't make any difference.
    - raverbashing 11y ago
      I would guess viscosity of a fluid is a function of atomic weight and intermolecular forces, both are higher in N2 than in He
    - Grishnakh 11y ago
      Nitrogen = air. Around 77% of air is nitrogen, much of the rest of oxygen, then some CO2, and the rest is trace gases. You don't get any improvement in most things by using pure nitrogen instead of air, unless one of those other gases was causing you a problem (in the case of tires, oxygen degrades the materials the tires are made of). The point of helium is that its molecules are much smaller and lighter than that of regular air so there's less friction. You don't get that with nitrogen. You would get it with hydrogen though (which is quite a bit smaller even than helium), though there's probably some other problem with H2 that prevents that. And yeah, a vacuum should be ideal; the problem there is probably that atmospheric pressure, at 14.7psi (IIRC) is pretty significant, strong enough to hold your suction-cup-mounted cellphone to your car windshield, so you have to have a pretty robust hard drive enclosure to maintain that vacuum without crushing. Vacuum chambers are usually really beefy. It would be interesting to see a vacuum hard drive; I wonder if WD ever tried that, just to see what it could do. They probably just can't make it and stick with the regular 2.5" or 3.5" form factors. Maybe a double-height 3.5" size (with the internals being the same size as a regular 3.5" drive, the rest just being extra structure) would be possible.
basicplus2 11y ago
Large power station alternators are hydrogen cooled.. that's right the whole alternator is filled with hydrogen. you have to monitor how close you get to the upper explosive limit. at a tenth the windage and ten times the heat transfer capacity of air, the stator and rotor can be a hell a lot closer and magnetic coupling more efficient therefore massive savings in construction and more efficient energy conversion to electrical energy
- todd8 11y ago
  Strange, but true: - https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generator https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generato... - http://www.power-eng.com/articles/print/volume-113/issue-6/features/hydrogen-cools-well-but-safety-is-crucial.html http://www.power-eng.com/articles/print/volume-113/issue-6/f...
gambiting 11y ago
Hydrogen escapes from any container you put it into. Normally it's contained in 70kg lead bottles(1kg of hydrogen per bottle), but all of it still evaporates within 3-4 weeks naturally(and as it does so, it makes the metal brittle).
jandrese 11y ago
Hydrogen is a reactive gas. It is much more difficult to work with. Helium being a noble gas avoids many of the worst complications like making metal containers brittle.

How would hydrogen work instead? Or is it not trustworthy enough if there's an oxygen leak inside and a spark occurs?

by cordite 11y ago

How would hydrogen work instead? Or is it not trustworthy enough if there's an oxygen leak inside and a spark occurs?

deleted 11y ago

[deleted]

woodman 11y ago

Hydrogen is much harder to contain. [0] [0] https://archive.org/details/cihm_81141 https://archive.org/details/cihm_81141

donatj 11y ago

Hah, and then hard drives crash AND burn. I'd think nitrogen would be a better option, my shop fills my tires with it, supposed to be easier to contain.

woodman 11y ago
"Usage of helium inside a hard drive helps to reduce the drag force acting on the spinning disk stack and lower the fluid flow forces affecting the disks and the heads. As a result, HDD makers can install up to seven platters into a standard drive and also use lower-power motors and mechanics. This reduces the power consumption of the HDDs."
- donatj 11y ago
  Would nitrogen not? What about a vacuum then?
  - cataflam 11y ago
    Nitrogen is pretty close to air, which is already 80% nitrogen. The gain would be minimal. As for vacuum, it's harder to maintain, and wouldn't work anyway : https://news.ycombinator.com/item?id=11593997 https://news.ycombinator.com/item?id=11593997
  - b101010 11y ago
    "Disk drives depend on the head floating on a cushion of air, they are not designed to operate in a vacuum" https://en.wikipedia.org/wiki/Flying_height https://en.wikipedia.org/wiki/Flying_height
    - XorNot 11y ago
      I've always found that odd these days. Given that we're already not doing dumb magnetic manipulation anymore, is it not feasible to use a static magnetic field between the head and platter to the cushion the drive at all? The magnetic interaction with the platter would be presumably predictable, since it's the oscillation that's used to write the data.
  - gambiting 11y ago
    Considering that normal hard drives have regular in them, and regular air is over 78% nitrogen, I guess bumping it to 100% nitrogen wouldn't make any difference.
  - raverbashing 11y ago
    I would guess viscosity of a fluid is a function of atomic weight and intermolecular forces, both are higher in N2 than in He
  - Grishnakh 11y ago
    Nitrogen = air. Around 77% of air is nitrogen, much of the rest of oxygen, then some CO2, and the rest is trace gases. You don't get any improvement in most things by using pure nitrogen instead of air, unless one of those other gases was causing you a problem (in the case of tires, oxygen degrades the materials the tires are made of). The point of helium is that its molecules are much smaller and lighter than that of regular air so there's less friction. You don't get that with nitrogen. You would get it with hydrogen though (which is quite a bit smaller even than helium), though there's probably some other problem with H2 that prevents that. And yeah, a vacuum should be ideal; the problem there is probably that atmospheric pressure, at 14.7psi (IIRC) is pretty significant, strong enough to hold your suction-cup-mounted cellphone to your car windshield, so you have to have a pretty robust hard drive enclosure to maintain that vacuum without crushing. Vacuum chambers are usually really beefy. It would be interesting to see a vacuum hard drive; I wonder if WD ever tried that, just to see what it could do. They probably just can't make it and stick with the regular 2.5" or 3.5" form factors. Maybe a double-height 3.5" size (with the internals being the same size as a regular 3.5" drive, the rest just being extra structure) would be possible.

basicplus2 11y ago

Large power station alternators are hydrogen cooled.. that's right the whole alternator is filled with hydrogen. you have to monitor how close you get to the upper explosive limit. at a tenth the windage and ten times the heat transfer capacity of air, the stator and rotor can be a hell a lot closer and magnetic coupling more efficient therefore massive savings in construction and more efficient energy conversion to electrical energy

todd8 11y ago
Strange, but true: - https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generator https://en.wikipedia.org/wiki/Hydrogen-cooled_turbo_generato... - http://www.power-eng.com/articles/print/volume-113/issue-6/features/hydrogen-cools-well-but-safety-is-crucial.html http://www.power-eng.com/articles/print/volume-113/issue-6/f...

gambiting 11y ago

Hydrogen escapes from any container you put it into. Normally it's contained in 70kg lead bottles(1kg of hydrogen per bottle), but all of it still evaporates within 3-4 weeks naturally(and as it does so, it makes the metal brittle).

jandrese 11y ago

Hydrogen is a reactive gas. It is much more difficult to work with. Helium being a noble gas avoids many of the worst complications like making metal containers brittle.