In ancient Rome, people already know that double-layer containers could keep warm. In the ruins of Pompeii, people once dug a double-layer container.

  The modern Dewar flask was invented by the Scottish physicist and chemist Sir James Dewar. In 1892, Duval told Berg to blow the glass into a special glass bottle. This is a double-layer glass container, the two glass walls are coated with silver, and then the air

between the two walls is evacuated to form a vacuum. The silver on the two layers of the

gallbladder wall can prevent radiation and heat dissipation, and the vacuum can prevent

heat dissipation by convection and conduction, so the temperature of the liquid in the bottle is not easy to change. Later, Berg used nickel to make the outer shell to protect the fragile glass bottle. At first, this kind of Dewar bottle was only used in laboratories, hospitals, and expeditions. Later, it was also used on picnics or train trips.

  On January 20, 1893, Dewar announced the invention of a special cryostat (cryostat)-later called Dewar. In 1898, he used a Dewar flask to liquefy hydrogen, reaching 20.4K. The next year, the solidification of hydrogen was realized, and the vapor on the surface of the solid hydrogen was extracted to reach 12K. The container invented   

silver plated in the middle and evacuated into a vacuum. This container was later transformed into a well-known commodity-a thermos. In 1925, popular cheap plastic thermos bottles began to be sold.

   At the same time, similar vacuum insulated containers are required for the shipment and storage of liquid gas in the laboratory. Dewar invented the metal Dewar flask for storing liquid oxygen in 1906. For a metal container with a capacity of 110,000 liters designed for railway transportation, the daily evaporation rate of liquid oxygen is about 0.1%, and the daily evaporation rate of liquid hydrogen is about 0.8%.