I dont have any cooling specs on the tube, it is a 60's era Amperex which is
probably a Phillips or other Euro design. The tube doesnt have a water
jacket; I'll have to make one.
No, I dont want vapor, just water and the condensor would be fan cooled. Im
thinking of using an automotive external transmission cooler as a starting
point.
Carl
KM1H
----- Original Message -----
From: "John Lyles" <jtml@losalamos.com>
To: <amps@contesting.com>
Sent: Thursday, December 17, 2009 10:09 PM
Subject: [Amps] water cooling
>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
>
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