mikea wrote:
> On Mon, Apr 05, 2010 at 12:15:45PM -0400, TexasRF@aol.com wrote:
>> Larry, I wonder why your aversion to using water?
/*snip*/
> Water is just about the best solvent there is, and has the distinct
> advantage of being non-flammable. Water-based solutions are, on the other
> hand, pretty conductive, which isn't necessarily desirable in gear that
> uses high voltages.
Wrong, water (H2O) is an insulator. It is used with nearly 40 kV on
collectors of
klystrons and other high power UHF transmitting tubes.
Dirty water is conductive and it doesn't take much to render distilled water
conductive,
but you start with steam distilled water. ($1/Gallon at the most around here,
$0.49 / gal
at some food stores.)
> There's a large and publicly-available body of work on
> water-cooling.
>
> I don't know how much info is available on oil cooling; it is flammable,
/* Not necessarily, some cooling fluids would be hard to burn,
water will burn freely if
you separate the oxygen and hydrogen */
> which isn't necessarily desirable, either: there _will_ be leaks, and
> oil-resistant flexible seals cost a bit more than vanilla synthetic
> flexible seals. You might be able to use one of the silicone oils, but they
> pose some problems of their own, especially having to do with their extreme
> slipperiness. Even so, DC-444 (Dow Corning 444) is good up to 444°F, which
> is well above where you'll want to run tubes, is used as a heat transfer
> medium in solar-heating systems, and doesn't eat rubber as far as I know.
>
> One of the very nicest properties of water is its heat capacity: a _lot_ of
> energy is required to get it to boil.
Absolutely, almost anything you add diminishes it.
I vote for "steam distilled water" with a conductance detector in one of the
hoses.
It is cheep and can be replaced 4 time a year for purity. Keep all iron, steel
and most
plastics out of the cooling circuit. (use rubber or neoprene hoses)
--
Ron KA4INM - The next election, I know what is going to happen, I'm going
to help.
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