James Dewar (1842-1923) was a Scottish physicist and chemist living in London. During his life, he managed to receive many prizes and medals, to make an incredible number of discoveries, many of which played an important role in the development of the exact sciences. Among his achievements in physics, his contribution to the study of temperature conservation with the help of a device he created, called the “Dewar vessel,” is considered to be noteworthy. This unit is designed to store various substances at elevated or low temperatures.
History of creation
The Dewar flask is an upgraded version of the device, which was developed by the German scientist Weinhold. However, it has significant differences. Weinhold’s invention looked like a glass box with double walls, and Dewar significantly changed this design. By analogy with the box, his device was also double-walled, a vacuum was created between the walls of this device, and they were silver-plated, and in order to reduce the evaporation of liquid, the throat of the device was narrowed.
Application
Today, the production of Dewar vessels has reached industrial proportions, since they are used everywhere not only in various industries, but also in everyday life. Few people know that a thermos is also a Dewar vessel. As far as industry is concerned, Dewar vessels for liquid nitrogen and other cryogenic liquids are most often used here. Also, this device is often used in veterinary medicine and for storage of various biological materials.
Since different types of vessels have different purposes, they are used in different ways, although in all cases, before placing the contents in the vessel, it is necessary to bring it to the appropriate temperature, i.e., heat or cool. The temperature of the substance that is inside the device is maintained due to two factors: thermal insulation and the processes occurring with it.
Thermos
The most famous and popular type of Dewar vessel is a thermos. At the beginning of the 20th century, Reynold Burger slightly altered this device to make it suitable for domestic use. The glass flask was placed in a metal case, making it thereby safer and more durable, and the plug that was installed on the Dewar vessel was replaced with a stopper and a lid.
Initially, the inventor hoped that such a device would be used to store food, but as a result, a thermos became popular precisely because he could keep the temperature of drinks for a long time. The birthday of a thermos can be considered September 30, 1903, because it was on this day that the Burger received a patent for his invention and began production.
Although the story does not end there. Dewar, who found out that the upgraded version of his device was a commercial success and helped Burger to make decent money, filed a lawsuit. But since his device was not patented, the court did not satisfy his requirements.
The Dewar vessel, invented by a Scottish scientist, gained wide popularity almost immediately after its birth and does not lose it to this day. It is widely used both in industry and in everyday life, which makes it one of the most important inventions of the 19th century.