What thermos measures to prevent the three ways of heat transfer??
Due to the vacuum flask is mainly used for hot water heat preservation in the family, so it is also called thermos. The structure of the vacuum flask 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. Cold storage liquid on the other hand, if the bottle, the bottle can prevent the outside heat radiation in the bottle
Heat preservation principle of the vacuum flask Modern thermos is British physicist Sir James dewar invented 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 and call "Bottle", can make in the liquid inside regardless of ling, hot temperature remain unchanged within a certain time.
Thermos bottle stopper, cork is often used to or plastic, these two kinds of materials are not easy heat conduction. 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.
Vacuum flask of insulation, cold insulation function is the worst place around the bottleneck, more calories in it with the help of the conduction mode of circulation. 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 drink stay in 4. C. Water in the 60 s. C. Vacuum flask and closely related to people's work and life. With its stored chemicals in the lab, picnics, football game people use it to store food and drinks. In recent years, the outlet of the vacuum flask added many new things, make the pressure vacuum flask, contact vacuum flask, etc. But the heat preservation principle remains the same.
