[SBE] More on Thread named: Ultrasonic Leak Detection

[PuebloTallTower at aol.com]

Ladies and gentlemen:
 
I am sort of old, yet enjoy the informative threads as they present 
themselves...
 
I am so old that most of the high power installations I have worked, were 
"pressurized" coaxial systems, and I will provide you with my overview of the 
thread as it has presented itself.
 
 
Remember, nothing in life is perfect, anything designed not to leak, and that 
has seals and junctions will eventually leak.  (consider oil hydraulic 
systems for example).
 
However, if one really wishes to isolate minute leaks in a system as 
described, my fall back has always been to use automotive technology, as anything that 
has to do with cars and their systems and operations will be dirt cheap...
 
There has always existed what are called "refrigerant leak detectors" these 
items are very reasonable in cost, and are sensitive down to parts per billion 
... were one to simply inject some r-134a into the pressurized system, one 
could actually trace all the leaks easily.  My mechanic has shown me a leak in 
the case seal of my freon automotive refrigerant pump, that amounts to the loss 
of one can of freon in 25 years...    the sensor/detector is less than a 
hundred bucks and a 12 oz can of 134a without oil is 5 bucks.
 
now on the other hand, the reason for pressurization is to simply keep the 
rain from ingressing into the wave guide or coax.  a few ounces of positive 
pressure can do this easily.  we can receive a few ounces of positive pressure 
from a house hold aquarium pump which is rated for continuous service, and is 
designed to run a long time, simply use an automotive freon style desiccant 
canister, ahead of the air pump, and you have real dry air.  
 
I observe that leaks are not a problem as long as you have a positive flow 
that makes it to the end of the line in question.
 
For my own ham radio purposes, I determined a long time ago, simply allowing 
the air filled transmission line to "breath" at a proper pressurization port, 
having it breathe through a desiccant filter, keeps the line dry, as there are 
never any positive nor negative pressure on the line as the barometer moves 
up and down.
 
a closed line (-inside coax flange with pressurization port plugged) - will 
always suck in moisture during a rain storm, but an open one  in  the building 
will not.  the telephone guys figured this out a long time ago, and please 
notice that the bottom of the overhead line tap boxes, is always open to 
atmosphere, even though the multipair "Old time lead lines" and now poly wraps were 
sensitive to moisture.  
 
out of time now, good luck...    hope it reads well, as I have not had time 
to re-read   
 
 
Harvey E. Smith
2020 Baculite Mesa Road
Pueblo, CO., 81001-2456

719 546 1418
719 671 2671
PuebloTallTower at aol.com or
HarveyEsmith at aol.com





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