What am I?

[dalangdon]

The utility I work for used to use liquid nitrogen at the receiving substation by my workplace, but they stopped back in the early 90's. The tanks are still there though.

It was/is a fascinating mechanism. The whole substation is, as it's been there since the 30's, and still has some original equipment. The control house is a great WPA-era structure with a bunch of weird stuff in the basement. While almost everything else, including the dams, have been largely automated, they still keep old-school operators at that place, mostly because of the steel mill.

I know that our downtown network system uses oil filled conduits as a means of cooling conductors, but that is far above my paygrade

 

[bobbyderegis]

Can you imagine seeing that cannister after 9/11 on the streets of Manhattan? Up until a few years ago that would have caused a major public panic. Personally, I thought it was Toggle's laughing gas container. That's really why he's so cheerful all the time.
Bobby in Boston

 

[tolivac]

Some power company transformers use a nitrogen tank or and argon tank to use its gas to displace any air or oxygen from inside the transformer-this is to prevent oxidation of the transformer oil-if the oil becomes oxidized-instead of being an insulator it becomes a conductor.At the voltage these transformers operate it could mean the failure of the transformer and whatever homes and businesses it supplies power too.As power transformrs heat and cool-oxygen can be drawn into them-the nitrogen forms a "blanket" on top
of the transformer oil to prevent the air from getting into it.The nitrogen may also fill the unused space in a transformers "conservetor" tank-where the oil goes when it expands from heating.Its the tank you see above the transformer case.Some of the transformers in the transmitters have this.But they don't have the nitrogen tanks-have dehydrator pellets that absorb moisture and oxygen instead.
Oh yes RF transmission lines from the transmitter to the antenna for AM,FM and TV may have these lines filled with nitrogen or dehydrated air to prevent moisture entry and arc overs.The gas is maintained at a positive pressure so containiments can't get into the line.Have forgotten how may nitrogen tanks I have gone thru at radioi and TV stations-and dehydrator cartridges I have reviatalized.

 

[mielabor]

Aha, I already suspected that it was not for cooling. I can see that the nitrogen isn't liquid anymore once it has entered the tube into the manhole, otherwise ice formation would be visible. However, it seems rather cumbersome to have these dewars in the streets. I have never seen this here and I think that they would be quickly vandalised. All the interesting things you can do with liquid nitrogen!

 

[mielabor]

Now I think of it: has it something to do with pest control?