Cushing, Oklahoma, dubs itself the pipeline crossroads of the world. The tagline is emblazoned on a giant roadside sign fashioned out of pipes on the corner of Main Street and South Stiles Road. It has a valve and everything.
Something about hydraulics, pneumatics, and the effect of 1ATM over a silly gigantic soda can. That evaporation and out gassing. Can’t leave the liquid exposed to air or it will outgass. Can’t fill the can or empty the can if it’s sealed or it will implode or explode. So they float a cover over the stuff.
Why aren’t those tanks closed at the top?
They are covered, the lid lowers as the fuel drains.
You cannot have a gaseous headspace with petroleum, it’s dangerous.
Something about hydraulics, pneumatics, and the effect of 1ATM over a silly gigantic soda can. That evaporation and out gassing. Can’t leave the liquid exposed to air or it will outgass. Can’t fill the can or empty the can if it’s sealed or it will implode or explode. So they float a cover over the stuff.