ATF starts to break down at 170-175F which is why transmission failures are
so common. Running thru an air cooled cooler is one way to extend the life
and mitigate the temperature rise.
I hope we dont want to run the tubes at the seal temperature maximum either.
Carl
KM1H
----- Original Message -----
From: "Ron Youvan" <ka4inm@tampabay.rr.com>
To: "amps" <amps@contesting.com>
Sent: Monday, April 05, 2010 12:49 PM
Subject: Re: [Amps] liquid cooling
> Larry wrote:
>> The recent discussion on water cooling amp tubes got me thinking. Again.
>> (not a good thing)
>>
>> Basically I would like to play with liquid cooling but I can't/won't use
>> water. While I was still working, I worked on a multi-kilowatt amplifier
>> that was oil cooled. It went into the avionics bay of an aircraft where
>> all the rest of the equipment was also oil cooled.
>>
>> As I recall, the oil looked and felt like mineral oil, but I'm sure the
>> military wouldn't use something that common and cheap and low flash
>> point. At the time, I pulled up the MSDS for the oil but no longer have
>> it and of course I can't remember the numbers.
>>
>> K8CU talks about using ATF for cooling liquid here:
>>
>> http://www.realhamradio.com/liquid-cooling.htm
>>
>> Unfortunately, there is no indication in the article that he or anyone
>> else actually used ATF. Now ATF contains sulphur compounds that eat
>> silver plating and cannot normally be used in things like dummy loads
>> because of this property. However, a set of heat exchangers used for
>> tube cooling would not have that problem.
>>
>> K8CU also mentions mineral oil and says it is not suitable due to the
>> low flash point. I have to wonder about that because for one I would
>> hope nothing in a system I would build would ever get hot enough to
>> worry about flash point and two, it probably won't flash anyway due it
>> being in a closed system with little or no free air/oxygen.
>>
>> What I'm looking for is someone who has actually done liquid cooling
>> with something other than water. No, I have no interest in "flat earth"
>> theories, or what you think you remember from a thermodynamics class you
>> sat through 40 years ago. I want actual test results and operational
>> data from real world applications.
>
> The L3 company has a division that makes "MDC IOT" transmitting tubes,
> their date for
> these tubes indicates the cooling oil they use, which is a synthetic
> fluid.
> --
> Ron KA4INM - The next election, I know what is going to happen, I'm
> going to help.
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