Since the thermos in the family is mainly used for hot water insulation, it is also called a vacuum flask.The structure of the thermos is not complicated. Intermediate for the double deck glass inside, between the two layers into vacuum state, and silver plated or aluminum, vacuum can avoid heat convection, glass itself is a poor conductor of heat, silver plated glass containers can be internal to the external radiation heat reflection back. In turn, if the bottle is stored in a cold liquid, the bottle prevents the heat from the outside to radiate into the bottle.
The vacuum flask was invented by British physicist Sir James duval in 1892. He was on a gas liquefaction research work, liquefied gas in low temperature, first of all need to design a can make the gas container sealed off from the outside temperature, so he please glass technician berger for him blowing a double deck glass container, two layers of wall coated with mercury, and then take away the air between the two layers, forming a vacuum.This vacuum flask is called "du bottle", which can keep the liquid in it unchanged for a certain amount of time, whether it is cold or hot.
The bottle stopper, usually made of cork or plastic, is not easy to heat. Vacuum flask shell with bamboo, plastic, iron, aluminum, stainless steel and other materials, thermos bottle has a rubber gasket, bottle has a bowl shaped rubber mat, these are all for the sake of fixed glass with bravery, in case of collisions with the shell.
The worst place for insulation and cold storage is the bottleneck around the bottle. Therefore, manufacturing is always possible to shorten the bottleneck, the greater the capacity and the smaller the thermos bottle, the heat preservation effect better, under normal circumstances, can make the bottle within 12 hours of cold drinks stay at 4 ° C or so. Boiled water at about 60 ° C.