Re: water spark gaps

["Tesla list" <tesla-at-xxxxxxxxxx>]

Original poster: Terry Fritz <twftesla-at-uswest-dot-net>

Hi Steve,

	Although electric water cannons are off-topic on the Tesla coil list, we
need to take a look at them to be sure a water spark gap would avoid the
"explosion" thing.  Richard Hull has worked with water cannons as described at:

http://www.richmond.infi-dot-net/~rhull/highenergy007.htm

The picture shows a rather dramatic firing at only 150 joules!  Our gaps
may "dissipate" only around 5 joules per bang but at 120 times per
second...  Also the gap may produce explosive or at least flammable gasses
even on a good day...  There may be a chance that high energy discharges in
water will break the water into H2 and O2 gas and then ignite it to really
give a good "bang" either right then or after the gas has built up for
awhile.  Obviously, such effects are undesirable in our application.  If we
cause a small explosion of the water dielectric, there is some danger and
the possibility for gap damage to occur.  However, I wonder if a tiny
little explosion would help quenching?  Obviously this has gotten a little
messier than I had anticipated but it still seems promising taking into
account to data from our water cannon friends.  I originally was thinking
of a fairly well enclosed thing, but now it looks like it will have to be
able to safely handle a small explosion to at least on the experimental
version till such details can be worked out.

I am glad I asked first before messing with all this.  I would not have
seriously considered explosions before!

On another note, this takes pure de-ionized water and all that to get a
high electrical resistance which is important for a water gap (although
adding axillary gap may be an alternative).  I "assume" one of those fancy
bottled waters, like Aqua-Pure, would be appropriate?


Cheers,

	Terry



At 10:15 AM 11/30/2000 -0500, you wrote:
>On Wed, Nov 29, 2000 at 06:09:30PM -0700, Tesla list may have written:
>> Original poster: "$" <Steve-at-g8cyerichmond.freeserve.co.uk> 
>> 
>> Some years ago I experimented with discharging caps through water spark
>> gaps. I stopped for eone reason only, it is extremely dangerous!!. The short
>> puls at high energy simply converts water to high high pressure steam (i'm
>> talking about steam at 100s of degrees C.
>
>Actually....I seem to remember reading a couple of years back some articles
>on some weapons researchers using this. Their "gun" would simply dump 
>electrcity into water on very short order (I am guessing capacitor discharge)
>and using the resulting explosion to fire a projectile.
>
>Accorrding to my memory, which is based on the article (though tends to be
>faulty over long periods of time) it wasn't just steam, it was actually
>producing water plasma. 
>
>As a side note, they said that while it made a very effective weapon, it
didn't
>scale up well. As they were having problems creating large versions of their
>weapon.
>
>-Steve
>-- 
>"You can't legislate intelligence and common sense into people"
>                -- Will Rogers 
>