Re: Plasma ball purged out/remedies?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Jan Wagner by way of Terry Fritz <twftesla-at-qwest-dot-net>" <jwagner-at-cc.hut.fi>


 > I know that this may strictly be "off topic" but since plasma globes were
 > recently mentioned on the list I'd like to say that
 > I have had a such a globe for three or four years and recently the display
 > has become very thin and hazy - it used to have bright lavender (argon?)
 > arcs terminating in red (neon?) pads over the years these have become
 > less bright now there is just a purple glow around the central
 > electrode.

Yeah, these don't last forever. Diffusion of the noble gasses through the
glass, water vapor from the glass getting inside the globe. No way to fix.

Rising the output voltage and current of the HV driver will give you
better streamers again for a while, but the problem is that then also
heat generation in the globe goes up... spot heating of the glass around
the electrode. Because gas pressure is so low, there's not enough
convection to get sufficient heat transfer away from the electrode.
So if you run it for "too long", the glass will crack, and there goes
your plasma globe. :-(  (this was the fast fate of my second,
large tube-style argon filled globe. powered it with a 50W SSTC -
too many watts... implosion.)


 > So I am looking for way to re-juvenate the globe to restore original
 > quality of the display.

AFAIK, not possible. At least not keeping the same gas mixture that's in
the globe (or rather, that _was_ in it). You'd have to refill the globe or
get another one.


 > Or will the globe actually have to be refilled- only,other than
 > replacement,this really seems like the worst possible scenario as it is
 > radical surgery; also I live in the UK where such facilities seem to be
 > scarce or non-existant- who might provide such a service?

Strattman (www.strattman-dot-com) does refills. The only place I know that
does refills, on this planet. ;) They also make very cool globes, tubes,
and panels.
    http://strattman-dot-com/pricing.html#plasmarepair
They aren't in the UK, but if your plasma globe is large then refill cost
vs postage/courier may still work out as "relatively affordable".

OTOH, from www.ebay.de - search for "Plasmakugel" - you can find many
small 20..30cm diameter toy globes with 2 year warranty for around 20EUR
or so.

cheers,
   - Jan

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  Jan OH2GHR