[SBE] nitrogen

[Gary O'Guinn]

No I believe the question was "has anyone used *liquid nitrogen*..." The 
question was answered; it was stated that it would be difficult to 
regulate the evaporation rate - the pressure -. We use a low pressure 
nitrogen generator at our transmitter site. It was expensive up front, 
but it saves us the expense of purchasing and transporting nitrogen 
tanks- especially since our transmitter site is 62 road-miles from the 
studio. It had a few startup problems. Mainly the supplied high pressure 
air compressor was under rated, so it kept failing. It was eventually 
replaced with an larger external unit and it has been operating well. We 
pressurize three 800 ft transmission lines at about 4 lbs pressure.

Gary O'Guinn
KTUU-TV Anchorage

Larry Will wrote:

> In line with Barry said about N1Hi.

>

> Wasn't the original question about "has anyone used nitrogen instead 

> of dry air for pressurization of MW lines?

>

> and WHY has NO ONE answered the question - a common problem with this 

> SBE reflector.

>

>

> I will answer it  now.

>

> I have used both dry air and nitrogen on large rigid lines, smaller 

> M/W lines and 2 way radio lines.  Both have their place.  I have also 

> very successfully cleared 12 gig elliptical lines that got "filled" 

> with ice due to leaks (mainly from failed windows in the dishes with 

> no radomes) where the birds picked holes in the windows.

>

> I did this on days when the air temp was well above freezing by 

> heating the nitrogen as it left the bottle (in the building) on its 

> way up to the leak.  It took quite a while - sometimes a day or two 

> and many bottles but the water was finally purged and the circuit 

> returned to normal fade margin.  Much cheaper than riggers and new cable.

>

> Now to answer the original question - using compressed nitrogen rather 

> than compressed air means simply from chemistry 101 is that nitrogen 

> is inert that is no corrosion no oxidation etc occurs.

>

> At my plants I always used nitrogen rather than dry air when it was 

> practical.

>

> Larry H. Will, P.E.

>

> Retired D.E.

>

> NJ Public TV.

>

>

> At 04:56 PM 5/6/2009, you wrote:

>> preferably the hot kind, freshly exhaled...

>> On May 6, 2009, at 15:50 , Dennis C. Brown wrote:

>>

>>> CO-2 is heavier than air.  Wouldn't that make shipping more expensive?

>>>

>>> Gary Blievernicht wrote:

>>>> My suggestion was to use CO-2 for the ingredient in bubble packs.

>>>> I've long worried that the more bubble packs the more air trapped

>>>> in them the less to breathe.

>>>>

>>>>

>>>> ------------------------------------------------------------------------ 

>>>>

>>>>

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>> -- 

>> Henry M. Seiden

>> henry<at>techworkspro<dot>com

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