Why does the stainless steel thermos not keep warm after a few months to a year? There is no collision when using.

Why does the stainless steel thermos not keep warm after a few months to a year? There is no collision when using.

Reasons for not keeping warm:

1, poor sealing affects heat preservation: the common thermos cups on the market are generally stainless steel and vacuum water containers with a lid at the top and tight sealing. Vacuum insulation layer can delay the heat dissipation of water and other liquids to achieve the purpose of insulation. The lack of gasket and the loose cover will make the sealing performance worse, thus affecting the thermal insulation performance.

2. Air leakage in the cup: There may be problems with the material of the cup itself, and some thermos cups are defective in technology. There may be pinhole-sized holes in the inner container, which will accelerate the heat transfer between the two cup walls, so the heat will be dissipated quickly. It is also possible that the interlayer of the thermos cup is filled with sand. This is a means for some merchants to make poor quality thermos cups. This kind of thermos cup is still very warm when it is bought back, but after a long time, the sand may react with the inner container, causing the thermos cup to rust and the insulation effect is very poor.