Date: Mon, 13 Apr 2015 07:46:17 +1200
From: Steve Wright <stevewrightnz@gmail.com>
To: amps@contesting.com
Subject: Re: [Amps] Amps Digest, Vol 148, Issue 15
On 13/04/15 00:10, amps-request@contesting.com wrote:
> The anode air cooler could be removed. In its place, a small copper (or
> aluminum) liquid cooling block --considerably smaller than the original air
> cooler-- could be made in a machine shop in a couple of hours.
The cooling will be worse than air cooling, not better, as the ceramic
and other parts of the tube have no cooling at all, unless I add a fan,
which I dont want to do. I want a fully integrated low-maintenance system.
> I would use distilled water, and replace it regularly. It's cheap, readily
> available, and is a better coolant.
>
And its a pain in the butt tocks always having to jigger with the amp.
I build things so that I am more a liability to them than the other way
around.
Steve
## so exactly what is the issue with oil vs distilled water ??? Distilled
water
can be found in 4 litre jugs, cheap, at any grocery store. To the best of my
knowledge,
distilled water will extract heat a lot faster / better than oil. I only saw
1-2 small tubes in the
entire Eimac catalog that used oil cooling. All their big commercial broadcast
tubes are either
air, or water, or vapor phase cooled tubes. Or multi-phase cooled.... which is
a combo of
water cooled and vapour phase cooling.
## at least if you had a leak..with distilled water, you wont get a mess like
with oil.
If it was me, Id use a combo of distilled water + water wetter. The water
wetter,
added to the distilled water, stops bubbles forming. Water wetter is sold at
any
automotive parts stores. I use it in both my engine radiator.....and also in
my roots
type supercharger on my mustang V8... ( intercooler-heat exchanger-
pump-degas loop).
## At the local race track, they will not allow the use of glycol mixed in
with distilled
water in any engine radiator. They will only allow distilled water + water
wetter.
Distilled water + water wetter is a proven winner. It will reduce engine
coolant temps
by at least 20 deg F. Water wetter is sorta like soap, reduces surface
tension.
A lot of the water wetter products have a rust inhibitor included in their
formulation.
## last year, I tested distilled water vs tap water with just a fluke 87
dvm. The
dc resistance of distilled water is sky high compared to tap water. Distilled
water is
a superb insulator. Dunno what happens to the dc resistance once water
wetter is
added to the distilled water. I should re-run the test. For a tube cooling
application
it’s a moot point, since it’s a closed loop anyway.
## Viscosity of distilled water + water wetter is going to be a lot less vs
oil. Distilled
water should flow easier through the tube, plumbing and any external pump +
radiator.
## However, the xfmr oil I used in my dummy load is low viscosity stuff. It
sloshes around
just like water. For a closed loop setup, oil or water will work of course.
The big advanatge
to oil is its boiling point will be a helluva lot higher vs water. In a
closed loop system, under
just 5-15 psi of system pressure, plus water wetter being used, the boiling
point of water
will be a lot higher than the normal 100 deg C.
Jim VE7RF
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