A vacuum bottle is a container that can isolate the gas from the outside temperature

Vacuum bottle refers to a container that can isolate gas from external temperature or isolate external bacteria.
The modern vacuum flask was invented in 1892 by British physicist Sir James Dewar. At that time, he was doing a research work on liquefying gas. To liquefy gas at a low temperature, he first needed to design a container that could isolate the gas from the outside temperature. So he asked Berg, a glass technician, to blow a double bottle for him. Two-layer glass container, the inner walls of the two layers are coated with mercury, and then the air between the two layers is sucked out to form a vacuum. This kind of vacuum bottle is also called "Du bottle", which can keep the temperature of the liquid in it unchanged for a certain period of time regardless of whether it is cold or hot. Because the thermos bottle is mainly used for hot water heat preservation in the family, it is also called a thermos bottle. The structure of the thermos bottle is not complicated. The middle is a double-layer glass liner, which is vacuumed between the two layers and plated with silver or aluminum. The vacuum state can avoid heat convection. The glass itself is a poor conductor of heat, and the silver-plated glass can radiate the inside of the container outward. The heat energy is reflected back. Conversely, if a cold liquid is stored in the bottle, the bottle prevents heat from radiating from the outside into the bottle.
The contents of the vacuum bottle can be completely isolated from the air to prevent the product from oxidative deterioration and bacteria breeding due to contact with the air, and use its high-tech concept to upgrade the product grade. The vacuum bottle prevailing on the market is made up of a cylinder into an ellipsoidal container plus a piston placed at the bottom. Its design principle is to use the contraction force of the spring to prevent air from entering the bottle, resulting in a vacuum state, and to use atmospheric pressure to push the piston at the bottom of the bottle forward. However, since the spring force and atmospheric pressure cannot give enough force, the piston cannot be too tightly attached to the bottle wall, otherwise the piston will not be able to rise and move forward due to excessive resistance; Therefore, vacuum bottles have very high requirements on the professionalism of manufacturers.