Re: Inert gas SG

["Bert Hickman" <bert.hickman-at-aquila-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Alex,

This information is sometimes a bit hard to find, and various sources
sometimes give somewhat conflicting numbers. From Sarjeant and Dollinger
("High Power Electronics), the breakdown voltage for some common
dielectric gases are:

Gas:		kV/cm
====		=====
Air             23.0
Nitrogen        22.8
CO2             24.0
SF6             67.0
Argon            3.4
Helium           1.3
Hydrogen        12.0 

As you can see, the breakdown voltage for helium and argon is very low
compared to most of the others. However, for best quenching, pure
hydrogen gas is the best performer. Static "quenching" spark gaps used
in early spark radio sometimes used pure copper electrodes sealed in a
container that was initially saturated with ethyl alcohol vapors. As the
gap was run, any oxygen was scavenged by the electrodes, and the alcohol
vapors were disassociated to leave a hydrogen atmosphere that was ideal
for rapid quenching.

Good luck, and let us know how your experiments work out.

-- Bert --

Tesla list wrote:
> 
> Original poster: "Alex Madsen" <alexmadsen-at-netzero-dot-net>
> 
> Inert gas SG
> I was thinking to avoid oxidation on SG one should be able to fill ones SG
> with an inert gas such as He, Ar or CO2(will the co2 brake down -at- 15kv?) and
> avoid the UV and x-rays produced in a vacuum. Unfortunately I can not find
> the breakdown (dielectric) voltage for any of these gases. Even in my Chem.
> and Phy. Handbook.  Does any one know where I can find this info? My pan is
> to build an air-tight Plexiglas box to go over my SG with some valves in it
> to let in the gas. If it is strong enough I will first evacuate it with a
> vacuum pump. If that does not work I would just have to flush it out with a
> lot of gas which could get expensive fast!! I will also need to build some
> sort of manipulator to adjust the SG.
> Comments please
> Alex Madsen    qpvvv
>     l                     ll
> 
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