Thermos flask is invented by the scientists named Dewar in England. In 1900, he first compressed hydrogen becomes a liquid, that is liquid hydrogen. This thing starting from a bottle, and it did not have such thermos flask at that time. So he developed his own. His vacuum approach that made double bottle, deprived of air in the compartment, and cut off conduction. But this is after the thermal radiation can also affect insulation, Dewar vacuum compartment and coated with a layer of silver or reflective coatings, thermal radiation blocking back. Use a plug blocked the mouth of the bottle. This thermal conductivity three are cut off bottle liner is a long time to maintain the temperature. He will use this bottle to store liquid hydrogen. Later, there is a wide range of application, and then almost every family has thermos vacuum flask.
Thermos flask is composed of liner, shell and additional components. The thermos liner: glass bottles from both internal and external combination. Both connected into one bottle at two sidewall gap evacuated to weaken the thermal convection, jar, plated shiny silver film reflectance infrared thermal radiation. Vial at high temperature, the heat energy of the contents does not radiate outward; cryogenic vial, bottle outer heat not inwardly radiation, thermos effectively controlled conduction, convection and radiation of the three kinds of heat transfer pathway. Apart from the flask that made of glass, there is also vacuum flask made of stainless steel, which is what we usually refer to stainless vacuum flask. Bottle the gall insulation performance the metal bottle gall rugged, difficult to damage, but the thermal conductivity is much larger than the glass, made somewhat less. Single or double wall plastic container, filled foam insulation, lightweight and convenient, not broken, but the insulation performance is worse than vacuum bottle gall.
The vacuum flask can be divided into three categories: first is the small mouth bottle. Usually it is known as thermos flask. It has small diameter of the mouth, good insulation properties, mainly used to hold boiling hot water, fried avid concoction, hot drinks and cold drinks. Second is the big mouth portable thermos vacuum flask. Usually, it is also known as ice bottles. Mouth diameter of large items pick and place convenient the main costumes ice, sorbet, with a container of cold drinks, iced pharmacy, liquid gas, anti-fermentation substances also bloom hot food, hot drinks with container. The third is the cup-shaped portable thermos. Usually it is known as insulated cup. The mouth portion is large diameter, small capacity, mainly for eating with a short time and it can reduce the influence of ambient temperature on the contents.