A lot of klystrons for UHF TV used ion-exchangers ( we called them scrubbers )
to help remove the brass / copper / stainless / whatever ions were present.
Don W4DNR
Quoting "Roger (K8RI)" <k8ri@rogerhalstead.com>:
Not sure what you are disagreeing with. Distilled water presents a
high resistance when first used, BUT, distilled and de-ionized water
is ion hungry, or rephrased, quite corrosive. It will take the
strength out of brass fittings to the point where you caqn crumble
them between your finger.. IE, hose barbs. It is the metal ions that
increase the conductivity. Tap water (with no salt) is still
conductive)
As the water ages, the dissolved metal ions lower the resistivity.
That's why we monitor the resistivity. Eventually the resistivity
gets low enough that the water needs to be replaced with, fresh,
clean, distilled water.
73, Roger (K8RI)
On 2/20/2017 7:05 PM, Ray, W4BYG wrote:
FYI: I'm afraid I have to disagree on the statement below about
distilled water being conductive.
In industrial experiments in the use of distilled water, I found
it to be very non-conductive. If I recall correctly, it has a
measured conductivity of 50 to maybe 100 micro-Siemens per
centimeter squared. That's not much. Pure water becomes
conductive only if it becomes contaminated with salt like
contaminates. For a comparison, seawater typically measures in the
thousands of micro-Siemens per centimeter squared, because of the
high salt content.
While working on a clients project to do so, I spent many hours
attempting to inject RF into water of various solutions. It was
very difficult in the lab trying to get RF to propagate thru pure
water. Other more contaminated solutions not so much..
73,
Ray, W4BYG
On 2/20/2017 12:43 PM, Jim Thomson wrote:
Date: Thu, 16 Feb 2017 00:15:55 -0500
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
To: Big Don <bigdon39@gmail.com>
Cc: "amps@contesting.com" <amps@contesting.com>
Subject: Re: [Amps] SS amps watercooling - was PowerGenius XL
Wouldn't Amps, or Ham Amps be a better reflector for this thread?
Were talking distilled water here. If it's conductive enough to present
a danger, it's long past time for a replacement.
When I was a Tech (before going back to college) it was rare to have
water spraying around inside those 100, 200, and even 250 KW generators
and the load coils were exposed.
Water cooling is a simple, mature technology. Water cooling is rather
simple. It's the monitoring that can get complicated. In high voltage
areas, we used linear (solenoid) coils of clear Tygon tubing to get the
necessary high resistance.
The simplest was a clear plastic block, drilled and tapped for all the
water exhausts. You could see at a glance how well any water circuit
was doing. Simple, cheap, and foolproof "IF THE OPERATOR PAID ATTENTION".
73, Roger (K8RI)
On 2/15/2017 5:24 AM, Big Don wrote:
Water-cooled amps HEALTH TIP --
There are enough ways to *electrocute* yourself playing with amps
without having leaked water spraying everywhere....
Don N7EF
#### Wife uses distilled water for her breathing machine at
night. I just checked the
resistance of distilled water... vs tap water. Distilled water
resistance is sky high, I mean
really high. Distilled water comes in 4 litre jugs, dirt cheap
at any of the local grocery stores.
## I use it myself for the mustang engine and supercharger. Ditto
with the ford fusion.
At the telco I worked at, we used nothing but distilled water for
the huge 2 v dc cells, typ
24 in a series string. We brought in pallets loads of 5 gal
distilled water containers. We also
used distilled water for the big start batteries for the
emergency generators. These days,
start batteries are all sealed.
## distilled water is so dirt cheap, and resistance is so high,
and LDMOS only uses 50 vdc,
whats the issue ? You could toss a bucket of distilled water
into a 7 kv dc B+ supply..and
nothing will happen.
## BTW, per einacs care and feeding, it sez air cooling will
remove 50 watts per square CM
of internal anode area. Vapor phase cooling will remove 135
watts per square CM of
surface area. Water cooling will remove 1000 watts per square CM.
Vapor phase cooling is
only more eff, in that it does not require a pump, and uses a lot
less water. Depending on the size
of the rad, and if its mounted vert or horz, u may not even
require a fan for the rad.
## water cooling requires more water circulation, and a big rad,
and forced air through the rad,
but it will remove heatr faster than any other method... except
maybe freon.
## If u look at modern HVAC cooling sytens on commercial
buildings these days, they now mount the
huge rads parallel to the roof, instead of vertical. Heat
rises, and the rads work more eff if mounted
horz vs vertical. They still use a fan below the rad though.
telcos use lotsa AC during winter, due to the
heat of the equipment, so in winter, night time, cool wx, the fan
for the rad is not always required.
## In a lot of cases, they will shoot water through the vert
mounted rads, to cool em. They use
freon to do the actual cooling, and water to cool the freon, then
more water to cool the rads,so 3 loops
in total.
## For LDMOS, the pair of water lines could easily be routed to
else where, then a speed
controlled fan on a small rad, and ditto with a variable flow
rate pump. A 12,000 BTU small rad
from jegs, or any of the other speed shops cost < $50.00 And
thats for a .75 inch thick core.
The higher capacity rads are just thicker, like 1.5 inches thick.
I use one for my auto tranny.
oem cooler is marginal when a supercharger is used, so added a
high eff bar + plate type rad, in
series with oem rad, problem solved. Old style tube and fin
type rads are going out of vogue these days.
Small oil coolers and auto tranny rad coolers would work just fine
with distilled water.
## U would end up with a dead quiet LMOS setup. Use enough
combiners, and you could get..on paper,
5 or 10 kw pep out if required. Combining 2 or even 4 ... of
those 2.4 kw pep output LDMOS amps
has already been done. So you could use them as building blocks.
This is all into a dummy load
of course, for pure scientific analysis.
Jim VE7RF
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