Are you going to use a pump or go the thermosyphon route? If the later the
pipe on the transmission cooler is too small. My old '48 International
Harvester Cub uses the thermosyphon system to cool the 18-20 HP engine. A
small car radiator would work OK and you would not need a pump or fan.
Randy AB9GO
-----Original Message-----
From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
Behalf Of Carl
Sent: Friday, December 18, 2009 9:54 AM
To: jtml@vla.com; amps@contesting.com
Subject: Re: [Amps] water cooling
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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> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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