I’ve seen these things in several cities. Basically it’s a circular base that’s pretty big, say 100 feet across, with a metal structure rising up from the outer edge. Basically the structure looks like several rings stacked on top of one another supported by criss crossing members. This frame rises maybe fifty feet from the ground. Anybody know what these things are? Some kind of antenna, transmitter, missile silo? I’ve seen several in different cities here in the US, but I saw a bunch in the London area when I was over there. It’s been driving me nuts not knowing what they are.
Maybe it’s just the New Jersey part of me talking, but for some reason I think they’re expandable fuel tanks. Which are empty when you see them.
Or maybe it’s radar… 
natural gas tanks. there’s one near where I live. They rise and fall within the outer structure
This is an old picture of such a structure in the background. They are used to store and meter gas.
A big cylindrical thing that goes up and down? What kind of erection is that?
Thanks all(except Lumpy). That’s exactly what I was talking about.
Little postscript here:
If you rate NYC landmarks by mentions on radio traffic reports, the “Elmhurst Gas Tanks” have the Statue of Liberty, the Empire State Building and Yankee Stadium – all combined – beat cold.
Doughboy, welcome to the board. I do not see any reason for your coment against lumpy. While you can see that others have done what we could to help you out, there is nothing wrong with inserting a little humor and levity. There is nothing to indicate he meant any kind of offense and I do not think you should take it that way. We all post jokes and it is ok as long as it is not meant to be offensive or it totally disrupts the thread. So, lighten up and enjoy the board. Soon you’ll be making jokes too.
Yeah, but how much traffic goes close enough to the Statue of Liberty for it to be used as a landmark? “…and the roads in the immediate vicinity of the Statue of Liberty are still extremely flooded…”
Not anymore - they were taken down a few years ago.
SirRay, the E.G.T are gone (stunned smilie goes here)!?!?
Being a Manhattocentric kind of guy (…not really, as my prior NYC posts should attest…)I did not know that! Thank you for the news, as I will now update my cerebral files.
Damn, tearing them down ought to rank right up there with the destruction of Penn Station, Ebbet’s Field and the Central Park Casino.
This raises the question (to me, at least): what’s the purpose of them rising and falling? Seems to me there’d be a much less expensive way of measuring the amount of gas within.
frog, I do believe the raising and falling allows the tank to contain a variable quantity of gas under uniform pressure.
frogstein, it is for storage. If you want to store gas at constant pressure you need variable volume. That way you can meet peaks of uneven demand.
You can liquify so that you have part liquid part gas. Then you can use a constant volume but this has other problems (pressure and temperature).
So, it depends on the gas. Propane can be liquified at normal temperatures so you can buy a bottle of liquid propane. Natural gas on the other hand will not liquify at normal temperatures so either you need a huge volume, OR you have huge pressure OR you have to keep an extremely low temperature to keep it liquified.
Thirty-five years ago I lived within sight of those tanks. Sorry that they are gone.
frogstein They rise and fall as gas flows in and out. They act as a reservoir. High usage, gas flow out is higher than gas flow in, so the tank sections collapse. During periods of low usage the tanks refill and the sections expand to full height.
I could not say for certain, but the weight of the top tank section may be what provides the pressure to force the gas through the lines to the end users.
Slight hijack:
Here in the St. Louis area, Laclede Gas stores some of their gas under high pressure by pumping it into underground storage caverns in Northern St. Louis County.