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Posted

They are drying and or purging the cables as I understand it, not the boxes. I believe there is pretty much zero gas flow so once purged/ dried the the cables stay that way for a long time.

Nitrogen is used a lot to displace O2 for different reasons, it’s used in Beer brewing to prevent oxidation of the beer I guess. We even had an NIU (nitrogen inserting unit) on the Apache that pumped nitrogen into the fuel cells so the gas above the fuel wasn’t explosive, the NIU was really just an O2 concentrator, just the O2 was expelled overboard and what was left was mostly N2 and that was dumped into the aft fuel cell, the fwd fuel cell vent opened at a slightly lower pressure than the aft so the N2 flowed through both cells and overboard thru the front.

It had the side benefit if extending the life of the fuel cells it seemed.

Posted
2 hours ago, A64Pilot said:

They are drying and or purging the cables as I understand it, not the boxes. I believe there is pretty much zero gas flow so once purged/ dried the the cables stay that way for a long time.

Do you have a cite to support your belief?

It doesn't pass the sniff test: If no gas flow is required after 'the purge' then why do I see the tanks remain in place PERMANENTLY.  And, why do the cables need to be 'dried out' in the first place?  It seems far more likely that all the connections within the BOXES are prone to corrosion, NOT wires with all manner of insulation inherent in their construction.

Without out some form of verifiable proof one way or the other we are just another pair of SGOTIs disagreeing:D

Posted

It would be hard to seal the box to maintain a dry atmosphere.  

Not sure about why the cables need it either.  It is used in some communications cables to prevent moisture from condensing inside.

From Reddit - 

 

 

Posted (edited)
On 11/12/2024 at 12:51 PM, MikeOH said:

Do you have a cite to support your belief?

It doesn't pass the sniff test: If no gas flow is required after 'the purge' then why do I see the tanks remain in place PERMANENTLY.  And, why do the cables need to be 'dried out' in the first place?  It seems far more likely that all the connections within the BOXES are prone to corrosion, NOT wires with all manner of insulation inherent in their construction.

Without out some form of verifiable proof one way or the other we are just another pair of SGOTIs disagreeing:D

No I don’t have any kind of proof, and won’t because I really not that interested, but it is logical.

I have never seen it installed permanently, only when they are doing work, and even then I’ve only seen it very rarely, haven’t noticed it myself in years.

I had a friend now gone that started out life working for the phone company that told me. That’s not “proof” of course but it seemed logical to me.

He was the Dean at the A&P school in Americus Ga. started out teaching Avionics there years ago. He also told me that Bell telephone was the first to use a Solar Panel in Americus Ga. The first practical test of one in 1955. He was sort of a telephone and electronics Nerd.

I have no idea what a SGOT is

OK a simple search of “does the telephone company purge cables with nitrogen” turned this up.

Granted this is power cables, but I’m sure if I kept looking I would find it applies to any buried wire conductor cable even TV cables.

https://www.tdworld.com/intelligent-undergrounding/whitepaper/21165280/respond-rectify-and-restore-underground-electrical-systems

Edited by A64Pilot
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Posted
On 11/12/2024 at 10:51 AM, MikeOH said:

Do you have a cite to support your belief?

It doesn't pass the sniff test: If no gas flow is required after 'the purge' then why do I see the tanks remain in place PERMANENTLY.  And, why do the cables need to be 'dried out' in the first place?  It seems far more likely that all the connections within the BOXES are prone to corrosion, NOT wires with all manner of insulation inherent in their construction.

Without out some form of verifiable proof one way or the other we are just another pair of SGOTIs disagreeing:D

Telephone cables, especially old telephone cables have lots of problems when they get wet. Some of these cables that are still in service are well over 100 years old. the conductors were textile and paper insulated with a lead sheath. The lead sheath will corrode and get holes in it so they pump them up with dry nitrogen to dry them out. they need the bottles because they leak. If they keep positive pressure on the cables, it pushes the water out.

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Posted

Interesting article.  I will say that's more 'proof' than I can provide for my opinion! I have always seen them strapped to neighborhood phone boxes for years, but as you mentioned I've not noticed them recently.  Not sure what would have changed?  Maybe everything is fiber now and moisture not an issue?

SGOTI = Some Guy On The Internet

Posted
7 minutes ago, MikeOH said:

Interesting article.  I will say that's more 'proof' than I can provide for my opinion! I have always seen them strapped to neighborhood phone boxes for years, but as you mentioned I've not noticed them recently.  Not sure what would have changed?  Maybe everything is fiber now and moisture not an issue?

SGOTI = Some Guy On The Internet

In all cases it is much cheaper to install a fiber than replace the old multi conductor cables. the old cables are abandoned in place. 

In a past life I worked for the phone company or with the phone company for six years.

Posted
Just now, N201MKTurbo said:

In all cases it is much cheaper to install a fiber than replace the old multi conductor cables. the old cables are abandoned in place. 

Certainly.

I was trying to understand why I don't see the N2 tanks around anymore.

Posted
1 minute ago, MikeOH said:

Certainly.

I was trying to understand why I don't see the N2 tanks around anymore.

You are absolutely correct. they have mostly been replaced with newer technology so they don't have to maintain those ancient cables any more.

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