3 ms·
Many years ago, when Hyperloop's design was first announced, tlb pointed out that steel expands during summer, and that the expansion from SF to LA was roughly
by sillysaurusx 6y ago
Many years ago, when Hyperloop's design was first announced, tlb pointed out that steel expands during summer, and that the expansion from SF to LA was roughly 400m (if I remember correctly) over a so-and-so temperature difference during summer. Where does the steel go?
I'm not sure there's been a satisfactory answer to that question. Expansion joints are very hard when you need to maintain a vacuum.
- bodhiandpysics1 6y agoThis isn't actually a problem! We build gas pipelines all the time which suffer exactly the same problem. (and no, you don't want gas pipelines to leak!) You can use expansion joints, or grooved couplings that enable movement, and there are other solutions as well. I think the problem that people have is that they assume you need some really intense vacuum for hyperloop to work. .05 bar (the pressure at 60,000 ft) is fine, and so is some leakage into the pipeline, which you just have to pump out.
- bigbubba 6y agoNormal pipelines handle large amounts of thermal expansion in a way fundamentally incompatible with hyperloops: https://www.quora.com/Why-do-oil-pipelines-have-so-many-seemingly-unnecessary-bends https://www.quora.com/Why-do-oil-pipelines-have-so-many-seem... https://duckduckgo.com/?q=expansion+loop&iax=images&ia=images https://duckduckgo.com/?q=expansion+loop&iax=images&ia=image...
- pas 6y agoWhy would that be fundamentally incompatible?
- CyberDildonics 6y agoThe tube could sit on rollers and/or the expansion could go into pushing arcs out slightly more. There are probably a lot of solutions. It doesn't necessarily need to be a perfect vacuum. The less air in the tube, the less resistance there will be. I would guess there would be vacuum pumps constantly taking air out of it.
- markbaikal 6y agoThere are no expansion joints on continuous welded rail either. The track is instead clamped so strongly that it can maintain its alignment even under thermal stress. https://en.m.wikipedia.org/wiki/Track_(rail_transport)#Continuous_welded_rail https://en.m.wikipedia.org/wiki/Track_(rail_transport)#Conti...