Part 1 Rapid improvement of thermos liner
The heat preservation effect first appeared on the thermos bottle.
The post-80s and 90s may still have an impression of the bright red and green thermos at home when they were young. The glass liner is plated with a layer of mercury to make a mirror surface. The inner wall is silver and there is an extended “little tail” at the bottom. (This is a tail pumping vacuum process). This thermal insulation process is simple and effective. But as we all know, glass has a flaw – it breaks easily.
The craft is constantly evolving.
In the 1990s, Japan was the first to use stainless steel vacuum insulation liner instead of glass liner. This kind of liner can not only ensure the thermal insulation performance, but also is not easy to break, and the light-carrying thermos cup is also pushed out in time. The stainless steel thermal insulation liner has two layers of stainless steel. A special process is used to extract the air in the middle to form a vacuum layer, which blocks thermal conduction and slows down heat loss, so as to achieve thermal insulation effect.
After the breakthrough of vacuuming technology from tail to tailless, the “little tail” at the bottom of the inner tank disappeared.
Since then, as an important factor affecting the quality and safety of thermos cups and pots, stainless steel liner began to appear “contest”.
Part 2 Continuous update of stainless steel
In simple terms, stainless steel is a kind of steel. During the smelting process, the properties of steel are improved by adding alloying elements such as nickel, chromium, and manganese, so that it has corrosion resistance, and it becomes stainless steel.
304 stainless steel is widely used in the food and medical industries. After being treated with special craftsmanship, it is often seen in the inner liner of the thermos cup, tea leaks, etc.
In the thermos cup products, the liner has been fully upgraded, and 316 stainless steel is generally used. Compared with 304 stainless steel, 316 stainless steel has higher requirements on the content of nickel and chromium, and because of the addition of molybdenum element, the corrosion resistance and high temperature strength are greatly improved. The properties are more stable, and the tea has no peculiar smell.
Standards are still rising.
As a low-carbon series of 316 steel grades, 316L stainless steel has better acid resistance, corrosion resistance and oxidation resistance, so it can be used to hold beverages such as milk, coffee, juice, etc. in addition to drinking water.
* In order to ensure the taste of the drink, it is recommended not to serve it for a long time.
Friendly reminder: When buying a vacuum flask, you need to look for regular channels and merchants. Unqualified stainless steel liner will have the safety risk of heavy metal migration during use, which will affect your health.
In theory, as long as the quality of the insulation layer is well controlled and made thick, the insulation effect can be achieved well. This is also one of the key reasons why many people mistakenly believe that “the heavier the thermos, the better”. In fact, the thermos cup has an important usage scenario – “carrying”. When going out, users prefer to carry only “water” itself, so lightweight is an advancement direction of the thermos cup and pot industry. At the same time, it takes into account the thermal insulation performance and lightweight, which tests the craftsmanship and level of the enterprise.