[Lewie]

Does anyone know the difference, if any, between nitrogen purged versus argon purged binoculars? A quick search on the Internet made it sound as though nitrogren and argon were synonyms.

Thanks,

Lew

[solentbirder]

Hi Lew,
Both are suitable for purging binoculars and I certainly wouldn't make it a factor in choosing between makes/models. The molecules of Argon gas are larger than those of Nitrogen gas and you could argue this makes it harder for Argon to escape from a sealed unit. This is really hair-splitting though and in practice makes no difference.
Cheers
John

[Gramayr]

..they glow dfferent colours when charged with electricity.. doesn't help tho I guess..

[barry robson]

Hi Lawrie

Try contacting Dave Morgan at Minox who purge their bins with argon gas - he's very helpful.

It's dave(AT)minoxuk.co.uk or log on to the Minox site at Birdforum and pose the question there - you're bound to get lots of info!!

Cheers

B

[Swissboy]

Originally Posted by barry robson

Hi Lawrie

Try contacting Dave Morgan at Minox who purge their bins with argon gas - he's very helpful.

It's dave(AT)minoxuk.co.uk or log on to the Minox site at Birdforum and pose the question there - you're bound to get lots of info!!

Cheers

B

Oh, and please pass it on to all of us, thanks.

[Edward woodwood]

theoretically argon will purge slightly better...

i bet no one would ever notice the difference though

[engineer]

Nitrogen has an atomic number of 7, whereas argon has an atomic number of 18. Hence, argon is larger as John said. Larger molecules don't leak as easily as do smaller molecules.

Another issue is that argon is much, much less likely to react than nitrogen with other elements. This would make Ar filled bino's stay the same longer.

[Lewie]

All:

Thanks for all the good replies. I appreciate it.

Lew

[Tero]

Why would you want to carry all that extra argon weight over light nitrogen?

[Caty on the Bay]

Originally Posted by Tero

Why would you want to carry all that extra argon weight over light nitrogen?

You are joking, correct? The densities of the gasses, even under pressure, is low enough that one would not notice.

[normjackson]

Given the context of the temperatures a binocular is likely to be subject to and the materials inside it, not really convinced there is any significant difference between the reactivity of argon and nitrogen.

From Graham's Law :
http://en.wikipedia.org/wiki/Graham's_law
given that the atomic mass of Argon is 40 and the molecular mass of Nitrogen 28 the rate of effusion of nitrogen should be about 1.2 times that of argon. Not sure that is particularly significant either; eg. long term I'd have thought the quality of the O-rings is far more important.

[engineer]

Originally Posted by Tero

Why would you want to carry all that extra argon weight over light nitrogen?

It steadies the binoculars.

[elkcub]

As an former Space Agency employee I can assure you the quality of the O-rings is far more important for gas integrity than whether Argon or Nitrogen is used, assuming the O-ring material is suitable for use with the gas in question, which would be determined prior to material selection, fabrication, and subsequent assembly, and done in such a way to be validated by non-invasive testing at random or ad libitum intervals by a panel of independent recognized experts. This opinion draws on extensive related prior experience, but is neither authorized by nor reflects the policy of my former employer, and may be modified or changed as any data become available.

[bradshrike]

O-Ring failure is overrated and generally only occurs on those rare cold mornings in the Everglades.

As to gas, I prefer Helium to either Argon or Nitrogen... makes even a 15x56 a joy to carry.

[elkcub]

Originally Posted by Brad_A

O-Ring failure is overrated and generally only occurs on those rare cold mornings in the Everglades.

As to gas, I prefer Helium to either Argon or Nitrogen... makes even a 15x56 a joy to carry.

... with a tether.

[Tero]

Helium leaks through o rings. This is known for NMR magnets, in a vacuum container.

[mrpjdavis]

[quote=engineer]Nitrogen has an atomic number of 7, whereas argon has an atomic number of 18. Hence, argon is larger as John said. Larger molecules don't leak as easily as do smaller molecules.[quote]

Ah but, argon is a monatomic gas (i.e. consists of single atoms) and nitrogen is a diatomic gas (molecules contain two atoms), which would make nitrogen molecules physically much bigger. An argon atom has a relative mass of 40, a nitrogen molecule has a relative mass of 28. I suspect that he difference in mass is far less significant than the difference in physical size, as far as leaking out is concerned.

In reality, it matters not a jot, but I am an ex science teacher, and old habits die hard....

Pete

[Edward woodwood]

blimey Mr Davis

I was just gonna post that myself...

getting back into skool mode for tomorrow...

Tim, unfortunately still a science teacher

[ceasar]

Lotsa Gas going around on this thread!
Bob