Vacuum flask Modern Thermos flask was invented by British physicist Sir James Dois in 1892. At that time he was working on a study to make gas liquefaction, gas to liquefaction at low temperatures, the first need to design a gas and external temperature isolation of the container, so he asked the glass technician Berg for him to blow a double-layer glass container, two layers of mercury coated, and then remove the air between two layers, forming a vacuum. This vacuum bottle is also called "Du bottle", which can keep the liquid in the inside regardless of the cold, heat temperature will remain unchanged for a certain period of time. Because the thermos in the family is mainly used for hot water insulation, it is also called Thermos. The structure of the thermos is not complicated. The middle is double glass bottle gall, between two layers vacuum state, and silver or aluminum, vacuum state can avoid heat convection, glass itself is the heat of bad conductor, silver glass can be the inside of the vessel radiating heat reflected back.
Conversely, if the bottle is stored in cold liquid, this bottle can prevent the outside heat radiation into the bottle.