Paul
While the Stanley Steamer article was novel and way cool (no pun
intended), doing a vapor phase cooled amplifier, for a few kW, is not
economically feasible nor recommended. Plain water cooling where you don't
boil it, is just fine to remove the sort of heat flux you can expect in
1500 watt tubes. When you get to where the limit of plate dissipation is
reached for a given flow, then concepts like vapor phase and multiphase
(without external condensor) make more sense. The anode cooler design
(pineapple is one way it is done) is very important, as well as the flow
to get enough turbulence. One preferred technique is to have locallized
vaporization of the coolant right in the anode fins, slots, cuts, but not
have a runaway condition. The subject is way more complicated that I can
recite here, but there are some decent old papers by various tube makers.
Headaches of vapor cooling include basically operating a water distillery
in your coolant circuit, so that you must start with very clean water, and
keep dissolved oxygen low (ppm) to prevent copper oxides from occuring and
ruining the heat transfer efficiency of the inside of the water
jacket/anode. If long life is important to your operation, you will need
to stay on top of ph, oxygen, and other factors which aren't as important
in conventional water cooling, and not at all with air cooling.
Just a free opinion. Why do it if it is so complicated? If you are trying
to remove 1000 watts/cm^2 in a copper anode, then it starts to really make
sense.
73
John
K5PRO
> Date: Sat, 27 May 2006 12:12:23 -0500
> From: Paul Nix <paul_nix@ticnet.com>
> Subject: [Amps] Curious About Design Specs For Vapor-Phase Cooled PA
> I've been fascinated with vapor-phase cooled amps ever
> since I was a kid and read the article in 'QST' (~1965)
> on 'The Stanley Steamer'.
>
> It used an EIMAC 4CX1500 that had the anode cooler
> converted to a 'pineapple' design for efficient cooling
> by 'boiling-water'.
>
> I believe that it was probably the
> forerunner to the Alpha PA70V.
>
> Does anyone know of any design specs
> on the design of the 'pineapple' structure ?
>
> I've gone through some old tube manuals, plus done
> some searching-on-the-Web, but all that I've found
> are a few pictures that show some big shortwave
> tubes with the 'pineapple' cooling structure but no
> design specs/papers.
>
> I think it'd be fun to take a small external anode tube
> (and cheap if it got broke!), remove the air cooled
> anode fins and attach a 'boiler'.
>
> Comments would be appreciated.
>
> Paul, WB5AGF
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|