The thermal insulation effect of the thermos cup is mainly related to the manufacturing process of the product. The thermal insulation effect of different processes varies greatly. The common thermos cups are basically made of double-layer vacuum stainless steel and glass (the glass liner is coated with mercury for vacuum insulation). The production process and the thermal insulation effect of the thermos cup are not within the scope of this chapter, The experience shared today is not to teach you how to choose high-quality thermos cups. This article only explains the use methods.

When you have a thermos cup, its quality and capacity have become a foregone conclusion. If you want to improve the insulation effect of the thermos cup, you can only start with the use method and details! First of all, we should understand a scientific concept: a good conductor of heat can accelerate the loss of heat from an object, and a bad conductor of heat can slow down the loss of heat from an object. Stainless steel metal is an excellent conductor of heat. It absorbs heat quickly and dissipates heat quickly. Plastics, glass, ceramics and other materials are bad conductors of heat, and air is also bad conductors of heat. When it comes to heat, maybe you should ask me why all thermos cups are made of stainless steel and vacuum? The use of stainless steel is mainly determined by the characteristics of the material, such as safety, compression resistance and other factors. It is precisely because the air is a bad conductor of heat that the excess air should be pumped away, so the heat conduction will be slower! There are three ways of heat transfer: convection, conduction and radiation. Therefore, even in a vacuum environment, heat can be transferred, but the speed becomes slower. For example, the heat of the sun is transferred to the earth. The vacuum pumping of the thermos cup can only block the heat conduction as much as possible, but in fact, heat conduction will occur. When the temperature of the water in the thermos cup is higher than the external temperature, it can slow down the decline of the water temperature in the cup. When the temperature of the water in the thermos cup is lower than the external temperature, it can slow down the rise of the water temperature in the cup.

After understanding these principles, how can we prolong the insulation effect by using a thermos cup? First of all, when filling boiled water or ice water, we can put a little into it for preheating or precooling, then pour it out, and then fill it with boiled water or ice water (because the inner material will quickly absorb heat and reach the critical state), but don't fill the whole inner tank. Leave a gap (air is a bad conductor of heat) so that the water can't contact the cover, Due to the slow thermal conductivity of air, the bottle stopper isolates the convective heat transfer at the bottle mouth, and the water temperature drops slowly. Moreover, because there is air left, a large amount of air is discharged from the bottle due to thermal expansion at the beginning, and then the air temperature in the bottle decreases, which makes the atmospheric pressure in the bottle lower than that outside the bottle, which is more conducive to heat preservation.