Why can't a small thermos be compared with traditional heat preservation?

Small thermos can't compare with traditional thermal insulation, because the vacuum space of small-capacity thermos is small and the heat dissipation is faster, which is not as good as that of large-capacity thermos. Therefore, when we choose a thermos cup, we should try to choose a more moderate one, and the thermos cup will be better.

Generally speaking, the thinner the cup material, the longer the heat preservation time. However, the cup is easy to be damaged and deformed, which affects the service life. Measures such as covering the outer layer of the inner container of the thermos cup with metal film and copper plating can also increase the degree of insulation.

inner structure

One way to make a container similar to a thermos bottle is to take a jar and wrap it in foam insulation. Thermal insulation works for two reasons. First of all, foam is a poor conductor of heat. Secondly, the air trapped in the foam is not conducive to heat conduction. Therefore, the electrical conductivity decreases.

Because the air is divided into tiny bubbles, foam insulation materials also play a role in eliminating convection in foam to a great extent. Therefore, very little heat is transferred through the foam. Facts show that there is a better insulator vacuum than foam. A vacuum means no atoms. A complete vacuum contains no atoms.

It is almost impossible to achieve a complete vacuum, but it can be close to a vacuum. Without atoms, conduction and convection can be completely eliminated.

There is an evacuated glass bottle liner in the thermos. Inside the thermos bottle is a glass layer, and there is a vacuum around the glass. Glass bottles are easily broken, so they are wrapped in plastic or metal shells. Many thermos bottles can actually be unscrewed and the glass bottle liner removed.