Working principle
The design principle of the emulsion bottle is to use the force of the spring to shrink the air into the bottle, causing the vacuum state, and using the atmospheric pressure to push the piston forward of the bottle bottom. However, because the spring force and atmospheric pressure can not give enough strength, the piston can not fit too tightly with the bottle wall, otherwise the piston will not be able to go up because of too much resistance; otherwise, if the piston is easy to advance and prone to leakage, the vacuum emulsion bottle requires very high professionalism of the manufacturer.
History
The modern thermos was invented by British physicist Sir James Dewar in 1892. At that time, he was carrying out a research work on gas liquefaction. The gas should be liquefied at low temperature. First, the emulsion bottle needed to design a container to separate the gas from the outside temperature. So he asked glass technician Berg to make a double glazing container for him, and two layers of inner wall were coated with mercury.
Then the air between the two layers is pumped out to form a vacuum. The vacuum bottle is also called “duer”, so that the liquid contained in it can remain unchanged for a certain period of time.