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Re: [TCML] Large Plsma Tube
The formula for the energy released by the implosion of a vacuum device that
I have seen used in industrial safety documents in places that I have worked
is the energy released by the adiabatic expansion of the atmosphere into the
vacuum chamber.
For the curious, the formula that I have seen is on this page (think Work =
energy released during the implosion):
http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/adiab.html
On Dec 2, 2007 2:15 PM, Nick Field - HVFX Ltd. <nick.field@xxxxxxxxxx>
wrote:
> Hi Scott, All,
>
> Wayne Strattman of Strattman Design (http://www.strattman.com/) is a
> master of large plasma tubes and globes. I had the privilege of
> visiting his shop in Boston a couple of years ago and he had an amazing
> range of very nice equipment and beautifully made stock, from simple
> neon stuff to amazingly intricate sculptures.
>
> Wayne told me a story about one of the workers at his glass supplier who
> was permanently scarred in a fairly horrific way by the implosion of a
> large sphere whilst vacuum testing. From Wayn's description of the
> accident this guy was lucky to escape with his life.
>
> The guys who work for Wayne have been doing this for years, and they
> still have the occasional nasty accident. I'm not saying you shouldn't
> try this at home folks; I'm sure someone on this list has a vacuum
> processing system that would put Wayne's to shame. But before anyone
> orders their 36" sphere, they should bear in mind that handling large
> fragile pressure vessels needs a heck of a lot more thought that just
> 'apply vacuum, add gas and seal'.
>
> Safe Coiling,
>
> Nick
> --
> _____________________________
> HVFX Ltd. - Managing Director
> Mob - + 44 (0)798 514 1873
> Tel - + 44 (0)207 060 4839
> Fax - + 44 (0)207 117 3065
> www.hvfx.co.uk
>
> Scott Bogard wrote:
> > I order 12-in lighting globes from renovators supply warehouse for $9,
> > http://www.rensup.com/globes/40004.htm
> > but depending on your patience level, it may not be worth the effort to
> build a sealing/discharge system. I have been told you can order complete
> globes up to 36-in from corning glass, but you will pay a little more than
> $9! And I can't find them on their website. But if you did get one, all
> you would need to do is apply vacuum, add gas and seal. Good luck, I'm sure
> others will provide useful insights as well.
> >
> > Scott Bogard.
> >
> >> Date: Sun, 2 Dec 2007 11:36:48 -0800
> >> From: btmeehan@xxxxxxxxx
> >> To: tesla@xxxxxxxxxx
> >> Subject: Re: [TCML] Large Plsma Tube
> >> CC:
> >>
> >> Where do you guys get the big globes from? (or even medium or small
> sized
> >> globes) Do you have to have a glass-blowing setup in order to really
> play
> >> with these things or do you just order pyrex chemistry glassware?
> >>
> >> On Dec 1, 2007 7:35 AM, Bill Lemieux <gomezaddams@xxxxxxxxx> wrote:
> >>
> >>> PS: I forgot to mention the end-seals. Because the ends will probably
> >>> have to be flat, you should consider using 1/2" thick plate to span a
> >>> 6" distance. This is a bit on the overkill side for 15PSI of
> >>> pressure, but better safe than sorry! Make sure you don't introduce
> >>> any small cracks when you drill the plates for your electrodes, and
> >>> polish all edges to eliminate sharp edges or pits from drilling or
> >>> cutting. Use fine emery paper for this.
> >>>
> >>> Forget about using plastics for your end plates, it won't last. Among
> >>> other things, atmospheric helium and hydrogen will leak in (through
> >>> the material) over the passing years... possibly changing the
> >>> appearance of your discharge significantly. You're going to have
> >>> problems with that using epoxy seals anyway, but if the exposed area
> >>> of the epoxy seal is tiny and the thickness great (ie; .25") they
> >>> ought to be good for many years.
> >>> The higher pressure you can operate at, (approaching atmospheric) the
> >>> slower this leak problem will be.
> >>>
> >>> This is why old epoxy-sealed HeNe lasers died after about ten years -
> >>> the helium would diffuse out through the seals. Amazingly, because
> >>> there was still a low pressure inside the tube, you could rejuvenate
> >>> those old tubes by sticking them in a bag of cheap balloon helium, and
> >>> operating the tube - you'd check it every few days and eventually it
> >>> would be working as good as new. Take it out of the bag, and it would
> >>> once again be good for years. Of course, with modern diode lasers and
> >>> even cheap hard-seall HeN lasers being so plentiful, that isn't worth
> >>> the effort. Epoxy-sealed HeNe lasers are worthless now.
> >>>
> >>> - "Gomez"
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