How Thermos Vacuum Flask Work?
This article is about the stainless steel double wall vacuum insulated thermos flask, not for vacuum flask with glass inner.
How heat escape from a container/vessle/jug?
Heat can be escape via air, metal, plastic, water, but nearly can’t escape via vacuum layer.
Different material has different R-value
What we need to do is create a vacuum layer to prevent heat escape for your thermos vacuum flask.
We need to add copper lining on inner wall to reflect heat inside to prevent heat escape.
We need to use smaller bottle mouth to prevent heat escape for thermos vacuum flask.