Stan C. wrote:
>Hello gang.
> I have a chance to buy a water cooled amplifier using a single 3CW5000A7
> Eimac tube. I am told by Eimac that this tube is electrically the same as the
> popular 3CX3000A7. Here is my problem....I can get NO info on "how" to cool
> the tube. I have been looking into stainless steel heat exchangers,"fish
> tank" water pumps,water chillers,etc. I would like to hear from anyone who
> has ever built a cooling system,ran one,etc. From Eimac I was told the tube
> needs 7.7gpm to run at the rated dissipation (will never run even close to
> that). Most water chillers I see (small ones) only flow about 2-4gpm. And
> they are EXPENSIVE. So.....can anyone help out??
>
>Thanks for your time,Stan
>
>_______________________________________________
>Amps mailing list
>Amps@contesting.com
>http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>
There's some (not much) info in this document
http://www.g8wrb.org/data/Econco/tube-topics.pdf
about it.
Chapter 6 of the Eimac book 'Care and Feeding of Power Grid Tubes'
http://www.cpii.com/eimac/cfcontnt.htm
has more.
There's some complete data sheets on several water cooled triodes on my
web site http://www.g8wrb.org/ - you might find something useful
reading the data sheets on those tubes - in fact, there is (see below).
BTW, 7.7 gpm is not the sort of flow you are going to get from small
fish tank pumps, which some are suggesting. Just intuitively (thinking
about how long it takes to boil a kettle of water), that seems a hell of
a lot of water to dissipate 5kW to me. I just looked at the data sheet
on the Eimac 3CW40,0000A3
http://www.g8wrb.org/data/Eimac/3CW40000A3.pdf
and it needs
3 gal/min for 10 kW
4 gal/min for 20 kW
6 gal/min for 30 kW
8 gal/min for 40 kW
These assume an inlet of <= 35 deg C. I can't see why you would need
much more than 1-2 gal/minute myself. But you really should get the data
sheet (and if you have one. I'd like a copy for my web site). 7.7
gal/min seems very excessive.
Note that 3CW40,000A4 data sheet also mentions an Eimac Bulletin #16,
"Water purity requires in liquid cooling systems" I expect you will find
that on the Eimac site.
I know vapor cooling is very quite, and I expect water cooling is too,
but unless noise is an issue, I wonder if you should just go for air at
that power level - especially considering you say you will never run
even close to its limits. You might note that there are very few water
cooled tubes made of that power level - most are air cooled.
And if you buy the amp, and the tube dies, where are you going to get
another from? It does not seem Eimac sell it any more.
--
Dr. David Kirkby,
G8WRB
Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|