[Amps] water purity/conductivity in water cooled tube amplifiers

[Roger (K8RI)]

The system I worked on was installed around 1960 and AFAIK it came out 
of service around 2000 - 2010. As for the copper oxide, the  foot and a 
half to two foot long anodes of the tubes  in the 200+ KW generators 
looked like they'd been stuck in a sewer.  That deposit sure didn't look 
like what it really was :-D Back in those days changing the water was 
pretty much our only known option.

Just from the size of the pump, I think John's system was far larger 
than ours.

73, Roger (K8RI)

On 4/28/2018 1:37 PM, John Lyles wrote:
> I concur with Roger, and have always been taught to avoid using Brass 
> fittings in a high resistivity pure water system for amplifiers. Zinc 
> leaches out, but then again, I don't have systems with routine water 
> replacement, as we use Cuno or Culligan 'resin' beds and oxygen 
> removal bottles in a continuous purification loop. It is done in a 
> sidestream running a few GPM through these bottles, and they are 
> replaced about annually. The main DI system has 100 hp pump and is 950 
> GPM.
>
> In another building where I have a test amplifier and dummy loads, the 
> water does need replacement every 5 years or so, even with the 
> purification loop. Somewhere in the myrad of pipework, there are some 
> bad materials that will, over time, deposit copper oxide and other 
> coatings inside of hoses and anodes of tubes.
>
> John
> K5PRO
>
>
>
>> Date: Tue, 24 Apr 2018 11:21:01 -0400
>> From: "Roger (K8RI)" <k8ri at rogerhalstead.com>
>> To: amps at contesting.com
>> Subject: Re: [Amps] water purity/conductivity in water cooled, tube, >
>>     amplifiers
>> We use what we have, what we can afford, and / or what's available.?
>> That said, brass is one of the poorest metals to use with DI, or
>> distilled water.
>> BUT On the positive side, even with monster QRO amps, their runs are of
>> a relatively short duration.? I've seen around 30, 12KW RF generators?
>> that have shared cooling water running through them 24 X 7.? There was
>> the occasional down time for various reasons, but the resistivity was
>> only checked on a weekly basis.? 24 X 7 That's 168 hours each per week,
>> but with 30 that cooling system was receiving 5,040 hours per week.? If
>> the water is changed every 20 weeks, that is roughly 100,800 hours per
>> water change.? As I remember the water tank was somewhere between 500
>> and 1000 gallons
>> "IF" the amp has only a couple gallons capacity and it runs, say 25
>> hours per week, experience tells me that unless there is something
>> unusual about the system, "I would expect" the need to change the water
>> as once or twice a year. It might go several years.
>>
>> 73 and good luck,
>> Roger (K8RI)
>>
>>
>> On 4/23/2018 11:33 PM, Randy wrote:
>>> On 4/23/2018 9:28 AM, amps-request at contesting.com wrote:
>>>> ----------------------------------------------------------------------
>>>> I know that really pure water is actually corrosive and will do it's
>>>> best to gain ions in order to get to some natural level of
>>>> minerals/contaminants.??? I built the coolers out of several pieces of
>>>> brass and hard silver brazed it all together.? I know the electrical
>>>> current will cause an etching or eroding effect of the materials in 
>>>> the
>>>> cooler, but I used what I had.?? At this point, I have no idea how 
>>>> often
>>>> I will changing? out the water.? Could be after only 10 hours of 
>>>> use, or
>>>> it may be 100 hours and the cooler may rot out in no time.
>
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-- 
Roger (K8RI)


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