The Naked Scientists

The Naked Scientists Forum

Author Topic: krypton gas in diving  (Read 6137 times)

Offline johndiver

  • Jr. Member
  • **
  • Posts: 43
    • View Profile
krypton gas in diving
« on: 18/02/2005 13:25:54 »
When a scuba diver works in cold water wearing a dry suit, we inflate the suit with a little bit of air to make it more comfortable and provide some insulation from cold water. In arctic diving, sometimes argon gas is used for its superior insulation properties (as opposed to  helium, which transfers too much heat from the diver to the water). Neon is not used as it causes narcosis in the diver. However, has anybody any idea why krypton is not used? I would think its insulation value is greater than argon's, but haven't found if it is a problem physiologically or if the cost of krypton is too great.


 

Offline Ylide

  • Moderator
  • Hero Member
  • *****
  • Posts: 905
    • View Profile
    • http://clem.mscd.edu/~mogavero
Re: krypton gas in diving
« Reply #1 on: 21/02/2005 02:47:12 »
Krypton is inert physiologically so it's probably the cost.  Argon is the most abundent of the noble gases in the atmosphere (something like 0.5-1%) so it the easiest and cheapest to obtain.  



This message brought to you by The Council of People Who Are Sick of Seeing More People
 

Offline chimera

  • Sr. Member
  • ****
  • Posts: 475
    • View Profile
Re: krypton gas in diving
« Reply #2 on: 21/02/2005 19:25:14 »
quote:
Originally posted by Ylide

Krypton is inert physiologically so it's probably the cost.



Funny enough, it's krypton, not argon they managed to make some compounds with... (xenon was the first of the 'noble' gases to be found reacting with fluor - didn't know they had done quite a bit since then), but you are probably correct about the availability.  

http://mooni.fccj.org/~ethall/fluor/fluor.htm
 

Offline Ylide

  • Moderator
  • Hero Member
  • *****
  • Posts: 905
    • View Profile
    • http://clem.mscd.edu/~mogavero
Re: krypton gas in diving
« Reply #3 on: 22/02/2005 01:28:38 »
Yeah, krypton chemistry is spiffy.  It is still inert in the conditions in the human body, though.  (i.e. no toxicological effects)



This message brought to you by The Council of People Who Are Sick of Seeing More People
 

Offline chimera

  • Sr. Member
  • ****
  • Posts: 475
    • View Profile
Re: krypton gas in diving
« Reply #4 on: 22/02/2005 12:02:56 »
Wow! They research EVERYTHING these days... (the article is from 1964)

http://ajplegacy.physiology.org/cgi/content/abstract/208/3/407

and it seems strangely krypton is the odd one out, and has a slight inhibitory effect on (frog) nerves.

(And I was going to make a joke about how unlikely it is for a diver to be brushing his teeth (fluor) while breathing noble gases. Tsk.)
« Last Edit: 22/02/2005 12:09:15 by chimera »
 

Offline Jaap

  • First timers
  • *
  • Posts: 1
    • View Profile
Re: krypton gas in diving
« Reply #5 on: 18/05/2005 14:26:04 »
Hi

I happen to have a small bottle of Krypton that is left over and should be returned to the gas company so I'm thinking about using the rest of it as suitgas for my diving this weekend...
Krypton should be about twice a insulating as Argon. Lets se if I'm around after the weekend ;-)

« Last Edit: 18/05/2005 14:26:57 by Jaap »
 

Offline anthony

  • Full Member
  • ***
  • Posts: 65
    • View Profile
Re: krypton gas in diving
« Reply #6 on: 21/05/2005 13:49:14 »
Helium probably isn't used because the molecules are so small. You may have noticed helium balloons deflate. This is the reason why many helium balloons you can buy are metal coated, to stop the molecules penetrating the balloon. Helium is a monoatomic molecule, whereas hydrogen is diatomic and so doesn't have this problem. Mind you, I wouldn't have expected the size difference between helium and argon to be as large as between helium and hydrogen, something for someone to look up maybe. Of course, there are other reasons why divers don't use hydrogen in their suits. I suggest the reason why argon is used is just availablility, but it would be interesting to look up the solubilities in water/blood too.
 

Offline daveshorts

  • Moderator
  • Neilep Level Member
  • *****
  • Posts: 2583
  • Physics, Experiments
    • View Profile
    • http://www.chaosscience.org.uk
Re: krypton gas in diving
« Reply #7 on: 21/05/2005 14:08:52 »
Can I please volunteer not to go diving with a diving suit filled with an explosive gas mixture... as there will enevitably be some air seeping in there somehow...
 

Offline johndiver

  • Jr. Member
  • **
  • Posts: 43
    • View Profile
Re: krypton gas in diving
« Reply #8 on: 28/05/2005 15:52:35 »
Helium is not used as a dry suit insulator because it is a conductor of heat. Those tiny atoms transfer heat more easily than any other gas I know of.
I get the impression that argon is used as an insulator primarily because of its low cost and it is inert chemically.
During deep dives (below 30m) the pressue really changes things. For example, nitrogen gets pushed into the nervous system and creates a narcotic effect; oxygen becomes toxic at partial pressures exceeding 1.6 ATA. Here's a quote from an excellent reference written by Lee Somers, PhD.
"The ultimate hydrostatic pressure levels under which a human may function have not yet been determined. In dry chamber experiments with various breathing mixtures, helium has been successfully tested to 2,000 feet, neon to 1,000 feet, and nitrogen-oxygen below 300 feet. Helium produced no noticeable effects, and presumably, actual saturation diving using helium will eventually prove feasible at least to that test level. Neon seems to impose no mental or physiological limitations, but because it is more dense than helium, problems of pulmonary ventilation may impose a working limit below some depth (estimated to be 700 feet). Saturation exposures with nitrogen have not been conducted below 100 feet, although there is no reason to assume that they are not possible. The limiting factor with nitrogen rather than respiratory functions will be the narcotic effect at increased pressure. The limiting factor with air is the inevitability of lung damage from prolonged exposure to elevated oxygen partial pressures."
Good luck, and don't fill your suit with hydrogen!
 

Offline johndiver

  • Jr. Member
  • **
  • Posts: 43
    • View Profile
Re: krypton gas in diving
« Reply #9 on: 08/06/2005 05:00:45 »
Further reading uncovered fact that many inert gasses cause narcosis when breathed under pressure. Xenon is said to be so narcotic as to be useful as anesthetic.
 

The Naked Scientists Forum

Re: krypton gas in diving
« Reply #9 on: 08/06/2005 05:00:45 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums