Re: [TCML] Gaps (Brown PVC)

["David Rieben" <drieben@xxxxxxxxxxx>]

Hi Adam,

Up close and personal (within a few cm of the plasma
source) the UV is likely considerably more concentrated
than the UV of natural sunlight, striking the surface at a right
angle. The entire spectrum of sunlight on a clear day striking
at a right angle of the irradiated surface adds up to just over
1 kW/ square meter. I don't know how much of this energy
falls within the UV spectrum but I feel reasonably sure that
the UV radiation from the plasma of an SG of a say 2 kW
coil system from just a few cm away would be considerably
stronger than the UV spectrum of natural sunlight. OTOH,
PVC that is ruined by lying in all of the available sunlight
of the open elements 24/7 for a year or so would be exposed
to considerably more total UV than in the case of a medium
sized coil's SG UV exposure since Tesla coils are (usually)
ran on a very low duty cycle over any extended period of time.
I do know from personal experience that the plasma of an elec-
tric arc emits quite concentrated UVs, as I have sustained a
nasty "sunburn" on the exposed skin of my arm from arc
welding before when I was welding in a short-sleeved shirt!

David

----- Original Message ----- 
From: "Yurtle Turtle" <yurtle_t@xxxxxxxxx>
To: "Tesla Coil Mailing List" <tesla@xxxxxxxxxx>
Sent: Monday, February 25, 2008 4:04 PM
Subject: Re: [TCML] Gaps (Brown PVC)


> Agreed. I've built some of the largest Ozone
> generators in Georgia. However, I've been working with
> PVC for decades, including in the tropics, and UV
> alone will not only brown, but completely destroy pvc
> pipe in only a year or so of sunlight. How much more
> UV does our spark gap put out than the sun?
>
> Adam
>
> --- Peter Terren <pterren@xxxxxxxxxxxx> wrote:
>
> > Don't just think of UV. There are a lot of nasty
> > reactive ions around the
> > gap including ozone and NOx. Also simple copper
> > oxide deposition is black
> > and will stain too.
> > Peter  http://tesladownunder.com
> >
> > ----- Original Message ----- 
> > From: "David Rieben" <drieben@xxxxxxxxxxx>
> > >
> > > ... Even Bart backed off of his original statement
> > > a bit by restating that he wasn't necessarily
> > saying that
> > > the UV would not cause browning of the PVC, only
> > that
> > > IF the temperature alone was causing it, then
> > there ob-
> > > viously was a serious deficiency of cooling. I had
> > thought
> > > that the UV was the issue in my case too but it
> > had been
> > > so long ago that I had forgotten many of the
> > details and
> > ... However, the posts that you and Adam
> > > have sent in concerning this does seem to verify
> > my suspicion
> > > of UV as the main culprit of this PVC degradation.
> > >
> > > David Rieben
> > _______________________________________________
> > Tesla mailing list
> > Tesla@xxxxxxxxxxxxxx
> > http://www.pupman.com/mailman/listinfo/tesla
>
>
>
>
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