I would recommend to check into the datasheet for flow volume versus
dissipation, if it is a well-spec'd tube. As for size of condensor, you are
talking vapor cooling I guess. One good source of info is to find an older
Thomson tube catalog, when they described their vapotron cooling technique in
the 1970s. Then they had Supervaporton. Once they went to Hypervapotron, it got
a lot more complicated in some ways, simpler in others. For instance, no need
for a condensor at all. But water purity and oxygen level, plus the type of
plumbing used, became very important. This is similar to CPI's multiphase
cooling, where the phase changes from steam to water in the water jacket of the
anode.
I have been using a pair of 4CW250,000B tetrodes all week as a pulsed 200 amp
power load. No RF, just DC driven with a pulse generator. They are loading my
plate power supply for testing, before I finish the RF amplifier that will be
drawing that current next spring. The power supply and capacitor bank (250 uF)
must function well together before i stick a very expensive cavity amplifier on
the end of the cable.
Each Eimac tetrode has 40 GPM flowing, water is about 1 Megohm-cm resistivity,
to allow no more than a mA or so of current in each 9 foot long 1.5 inch ID
water hose. The real amplifier will need 130 GPM in the anode, and 5 other
water loops of < 1 GPM for filament, screen, and cavity. When water cooling
shoot for keeping the temp rise across the anode at about 5 - 10 deg C or less,
and keep the flow reasonable for the pipe size, using standard pipe
calculations. Too much flow will erode fittings. Too high a resistivity will
strip ions from fittings and cause metal to move around and get plated in
places you'd rather not (like inside of anode or hose fittings). For hoses,
design them as a cylindrical resistor of water, and figure out the ohms per cm
or meter, and then just make them long enough to keep leakage small, under a mA
if possible. Use rubber, or polymer hoses or even PVC pipe, nothing with a lot
of dark carbon (black hose). RCA use to say something like 4 Meg ohm pe
r kV of
plate voltage I believe.
Happy Holidays
John
K5PRO
> Id like to test a Class C industrial tube (Not on a ham band!) Ive had for
> almost 25 years when I stripped the self excited oscillator for parts. The
> questions would be how to calculate the necessary flow volume based on plate
> dissipation, size of condensor, suitable hosing, controls, sensors, and all
> that good stuff.
>
> Carl
> KM1H
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|