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Assuming a drive contains helium at standard temparature and pressure, and contains about a liter in volume. That would be about 1 gram worth of helium per driv

Assuming a drive contains helium at standard temparature and pressure, and contains about a liter in volume. That would be about 1 gram worth of helium per drive.

margalabargala 2y ago
Hard drives are much, much smaller than one liter.
robocat 2y ago
0.05 gram Helium assuming: (1) half of drive volume is used for platters, (2) at 15° Celcius (3) at 1 atmosphere (I'm guessing not pressurised since that would defeat purpose of using Helium, although might be less than 1 atmosphere).. 0.376 litres for total 3.5-inch HDD volume from my first Google result: "Width: 101.6 mm, Height: 25.4 mm, Length: 146 mm". Actual volume used for platters is less than that. Helium is light ~ 0.169 g/litre from "0.169 kg of Helium is 0.999 m3 at 15°C": https://microsites.airproducts.com/gasfacts/helium.html https://microsites.airproducts.com/gasfacts/helium.html Note that I think comment assumed one litre of normal air not Helium: "The density of dry air is 1.2929 g/litre at STP".
- deleted 2y ago
  [deleted]
joezydeco 2y ago
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.
- banish-m4 2y ago
  MRI machines borked the MEMS accelerometers in iPhone due to helium contamination. I assume most smartphone sensors are now helium-tolerant.
  - joezydeco 2y ago
    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-information-iph301fc905/ios#:~:text=Exposing%20iPhone%20to%20environments%20having,damage%20or%20impair%20iPhone%20functionality https://support.apple.com/guide/iphone/important-safety-info....
    - lazide 2y ago
      Legalese - even cheaper than engineering, apparently.
- Y_Y 2y ago
  GE says over its lifetime (roughly 13 years) an MRI machine will use about 1e4 litres of liquid helium. Two thousand litres is a good estimate for the capacity of a machine, but it's not a useful figure unless you know how often you need to replenish it.

Assuming a drive contains helium at standard temparature and pressure, and contains about a liter in volume. That would be about 1 gram worth of helium per drive.

margalabargala 2y ago

Hard drives are much, much smaller than one liter.

robocat 2y ago

0.05 gram Helium assuming: (1) half of drive volume is used for platters, (2) at 15° Celcius (3) at 1 atmosphere (I'm guessing not pressurised since that would defeat purpose of using Helium, although might be less than 1 atmosphere).. 0.376 litres for total 3.5-inch HDD volume from my first Google result: "Width: 101.6 mm, Height: 25.4 mm, Length: 146 mm". Actual volume used for platters is less than that. Helium is light ~ 0.169 g/litre from "0.169 kg of Helium is 0.999 m3 at 15°C": https://microsites.airproducts.com/gasfacts/helium.html https://microsites.airproducts.com/gasfacts/helium.html Note that I think comment assumed one litre of normal air not Helium: "The density of dry air is 1.2929 g/litre at STP".

deleted 2y ago
[deleted]

joezydeco 2y ago

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.

banish-m4 2y ago
MRI machines borked the MEMS accelerometers in iPhone due to helium contamination. I assume most smartphone sensors are now helium-tolerant.
- joezydeco 2y ago
  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-information-iph301fc905/ios#:~:text=Exposing%20iPhone%20to%20environments%20having,damage%20or%20impair%20iPhone%20functionality https://support.apple.com/guide/iphone/important-safety-info....
  - lazide 2y ago
    Legalese - even cheaper than engineering, apparently.
Y_Y 2y ago
GE says over its lifetime (roughly 13 years) an MRI machine will use about 1e4 litres of liquid helium. Two thousand litres is a good estimate for the capacity of a machine, but it's not a useful figure unless you know how often you need to replenish it.