MSDC Klystrons ran around ten feet @ 32KV applied.
Don WA4NPL
Quoting Roger <sub1@rogerhalstead.com>:
> Although both distilled and deionized (DI) water have an affinity for
> copper and other metals, I'd not expect that to be much of a problem
> with the intermittent service at an amateur station. For good measure a
> small vinyl tank (5 or 10 gallons) could be used as a holding tank with
> the metal parts only receiving water when running. Use a buffer tank
> (one or two quarts) so with a pump failure the tube will have that
> reserve for protection.
>
> Likewise I'd stay away from soft solder connections like a radiator, but
> at amateur power levels it doesn't take a lot of water for efficient and
> sufficient cooling. However it does depend on the area of heat transfer
> from the anode to water. As a wild guess, I think it'd probably take
> between a pint and a quart per minute for a legal limit amp, or even one
> of the contest monsters.
>
> In another conversation the subject of water hose length came up. For
> those using anode water cooling how long a piece of tubing do you use
> for safety and isolation between the plate and ground, or where leaving
> the enclosure? It's been over 20 years since I worked with this stuff
> and "as I recall" we used between 15 and 20 feet of coiled hose from the
> anode running 6 Kv DC. IIRC it wasn't a lot more even in the big RF
> generators. I don't think we ran over 8 or 10 Kv DC on anything.
>
> 73
>
> Roger (K8RI)
> Carl wrote:
>> I would think that a cooling or heater core with soldered assembly would
>> create problems with the water purity pretty fast? Cant have anything in the
>> water to promote conductivity. Maybe a micro rice box plastic radiator
>> would work.
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message -----
>> From: "Randall, Randy" <Randy.Randall@healthall.com>
>> To: "'Carl'" <km1h@jeremy.mv.com>; <jtml@vla.com>; <amps@contesting.com>
>> Sent: Friday, December 18, 2009 11:24 AM
>> Subject: RE: [Amps] water cooling
>>
>>
>> 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
>>>>
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>> Confidentiality Notice: This e-mail message, including any attachments, is
>> for the sole use of the intended recipient(s) and may contain confidential
>> and privileged information. Any unauthorized review, use, disclosure or
>> distribution is prohibited. If you are not the intended recipient, please
>> contact the sender by reply e-mail and destroy all copies of the original
>> message.
>>
>> _______________________________________________
>> Amps mailing list
>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|