Carl wrote:
> Sounds like a job for good old PCB transformer oil maybe???
>
Actually good old Dow Corning 200 fluid.
There are no normal cooling fluids that have a greater thermal
conductivity than water.
I worked on a project with an engineer many decades ago trying to come
up with a substitute fluid for a solar heating system that could be used
in northern climates and not freeze at night. We had some pretty good
stuff (basically 200 fluid of different viscosities), but it was expensive.
As to those talking about tubes submerged in oil such as the rectifiers
in X-ray machines, that is primarily for insulation
73
Roger (K8RI)
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: <TexasRF@aol.com>
> To: <larry@w7iuv.com>; <amps@contesting.com>
> Sent: Monday, April 05, 2010 12:15 PM
> Subject: Re: [Amps] liquid cooling
>
>
>
>> Larry, I wonder why your aversion to using water?
>>
>> 73,
>> Gerald K5GW
>>
>>
>>
>> In a message dated 4/5/2010 11:07:23 A.M. Central Daylight Time,
>> larry@w7iuv.com writes:
>>
>> 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.
>>
>> 73, Larry
>>
>> Larry - W7IUV
>> DN07dg - central WA
>> http://w7iuv.com
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