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Re: (Flammable Caps, and) Hydrogen Sparkgaps.
Tesla List wrote:
>
> Original Poster: Sam Barros <sambarros-at-yahoo-dot-com>
>
> Therefore, Hydrogen is the very best gas you could possibly have in a
> sparkgap. It will heat up 5 times slower and get rid of the heat much
> faster. It will be smaller, and quench extremely well. The pipes will
> never oxidise either!
> Now, we already know this because all high-performance spark gaps
> (Marx banks, Trigatrons, etc…) are Hydrogen filled (sometimes at high
> pressures to further increase heat capacity and breakdown voltage).
> So, we should all agree that a Hydrogen gap would be THE way to go for
> a TC.
> Now, why don’t we use them? Well, it is difficult to make one. Now,
> here is my idea (You’ll love it:-)
>
> Ok. I am going to build a nice RQ gap, and close off both tops with
> PVC caps. I’ll raise the copper tubes a bit of the PVC pipe to avoid
> melting and I’ll fit 2 valves. Than, I’ll purge all the air from the
> gap and run it on My TC. There will be no oxidising, and the
> performance should be dramatically better.
> Note: I considered the fact that the pipes might vaporise and the
> vapour will lower the breakdown value of hydrogen before it deposits
> back into the walls. Maybe a way to circulate the gas would be
> necessary. That would greatly add to the difficulties of the system so
> I’ll leave it for now.
>
> Any ideas, comments?
>
The hydrogen will leak through the PVC remarkably quickly. As you noted,
hydrogen has a very low viscosity (why they use it in high performance
cooling applications like turbogenerators), so it has low drag through
tiny holes. It is also small in diameter (almost as small as He). So,
you'll need some sort of scheme to keep your container filled with H2.
Perhaps a small electrolysis rig? The commercial H2 filled devices use
glass and ceramic which is a bit more H2 impervious, and, most
important, they have a palladium H2 reservoir with a heater. H2 is
absorbed (or perhaps adsorbed, I'm not sure of the storage mechanism)
into the palladium, and then gradually released by heating the
palladium.
There is also some interesting info in Craggs & Meek where they talk
about running trigatrons in radar service (high rep rate, etc.) and
found that some oxygen in the chamber was actually helpful (as compared
with straight nitrogen or argon). I don't recall what it helped, off
hand, though. And, Fruengel seems to like quenched argon or hydrogen
gaps (the kind with a zillion stacked disks).
--
Jim Lux Jet Propulsion Laboratory
ofc: 818/354-2075 114-B16 Mail Stop 161-213
lab: 818/354-2954 161-110 4800 Oak Grove Drive
fax: 818/393-6875 Pasadena CA 91109