Daily necessities have shells made of bamboo strips, iron sheets, plastics, etc. on the outside and bottle bladders on the inside. The bottle bladder is made of double-layer glass. Both sides of the interlayer are plated with silver and other metals, and the middle is evacuated. There is a stopper at the mouth of the bottle, which can maintain the temperature inside the bottle for a long time. Those that hold hot water are usually called thermos bottles; those that hold cold food are usually called ice bottles.
Thermos flask: scientific invention by James Dewar of Scotland
The concept of a thermos flask is very simple: the bottle has an inner wall and an outer wall; there is a vacuum between the two walls, and there is nothing A thing (not even air in it). Heat cannot be transferred through a vacuum, so any liquid poured into a bottle can maintain its original temperature for a long period of time.
This is why thermos bottles keep drinks warm in the winter and cold in the summer. Many people who have taken many trips find it difficult to imagine what it would be like without a thermos.
But the thermos was not invented until 1892, although its inventor did not realize how useful it would be at that time. The inventor was Scottish scientist James Dewar.
Liquid oxygen was produced at a low temperature of -240 degrees Celsius. In order to preserve this liquid oxygen, Dewar designed a bottle in which heat cannot be transferred in or out. The thermos flask we use now , evolved from this "Dewar bottle". Dewar's thermos bottle is designed based on heat transfer: first, it is made of a two-layer glass bottle, with a vacuum in the middle of the bottle, which isolates the air from the heat second, the bottle wall is coated with mercury, which can reflect the heat radiation back into the bottle just like a mirror reflects light; third, the bottle mouth is capped with a stopper to prevent heat from escaping from the bottle mouth. To hold boiling water, it became a thermos flask.
However, it was German glassmaker Reinhold Berg who realized that thermos flasks would be useful in various situations. He patented the thermos flask in 1903 and made plans to bring it to market.
Berger even held a contest to find a good name for his thermos. The winning name he picked was "Thermos", the Greek word for heat.
Berger's product was so successful that he was soon shipping thermos bottles around the world.
Thermos flasks often serve scientific purposes, for example, when liquids need to be kept at a constant temperature. Vaccine, serum, and other liquids were also often shipped in thermos bottles.
Nowadays, thermos bottles are no longer coated with mercury. Before the 1960s, they were plated with silver, but now they are plated with magnesium oxide.
How to check the insulation quality of thermos bottles?
1. Check whether the teat tip (i.e. the air extraction nozzle) at the end of the bottle is intact. If it is broken, the vacuum between the sandwich layers of the bottle will be destroyed and the heat preservation ability will be lost.
2. Check the bottle bladder for signs of explosion.
3. Check whether the mouth of the bottle is round. If the mouth of the bottle is not round, the stopper cannot be sealed, which will reduce the heat preservation ability.
4. Check whether the asbestos pad has been displaced or fallen off. The asbestos pad is the three round black spots in the middle of the bottle. It is supported between the inner and outer bladders. If it is displaced or falls off, the bottle will burst because it cannot withstand the pressure of the water it should hold.