How long can a high quality thermos flask maintain the water temperature at room temperature?
The thermos flask is generally made of ceramic or stainless steel material, plus a vacuum layer to hold water. The top of the thermos flask is sealed tightly. The vacuum layer can isolate the water and other liquids inside from the outside air, so as to delay the heat dissipation of the liquid in the thermos flask, so as to achieve the effect of heat preservation.
Since the purpose of the thermos flask is to keep the temperature, what is the insulation effect of the thermos flask you buy in daily life? And how long can a good thermos flask keep the temperature?
Let's do an experiment: at room temperature of 20 ℃, put ice into the thermos flask, fill it up and place it on the table. In this state, after 6 hours, the ice does not melt. This shows that the holding time of the thermos flask is at least 6 hours, which is already a high-quality thermos flask. (Note: according to the capacity and caliber of the thermos flask, the temperature of the liquid in the thermos flask will be different after holding the temperature for a period of time. )
The length of holding time of thermos flask is not the most important indicator to judge whether the thermos flask is a high-quality thermos flask. At least for our health, we need to focus on another indicator, that is, the material of the thermos flask.
The thermos flask is made of stainless steel, which is also food grade. 304 stainless steel is an approved food grade stainless steel material with beautiful surface, good corrosion resistance and heat resistance. Its corrosion resistance and rust resistance are much higher than other stainless steel materials, and the cost is twice as high as that of common 201 stainless steel.
In addition to the material to use 304 stainless steel, choose stainless steel thermos flask should pay attention to "heavy metal". Heat cup also need to test heavy metals, the elements are as follows: cadmium, lead, nickel, arsenic, chromium.
For our life safety, we should buy the thermos flask with good safety performance.