Simple appraisal method of vacuum insulation performance;
(1) Pour boiling water into the thermos cup, tighten the cork clockwise, or touch the outer surface of the cup with your hands after 2 ~ 3 minutes. If there is obvious temperature rise in the cup, it means that the product has lost its vacuum degree and cannot achieve good heat preservation effect. The outside of the thermos cup is always cold.
(2) See if the internal seal is tight. Check whether the plug is properly matched with the cup body, whether the cup cover is freely screwed in and out, and whether there is water leakage. You can fill a glass of water for four or five minutes or shake it hard to verify whether it leaks.
Stainless steel thermos cups are mainly divided into: ordinary thermos cups (the heat preservation time is generally less than 3 hours after boiling water is poured in) and vacuum thermos cups (boiling water can be kept warm for more than 8 hours through vacuumizing).
Extended data:
1. The main reason why the thermos cup is not insulated is that the vacuum layer between the two shells is destroyed. There used to be a vacuum inside, but now there is air inside. So the thermos cup loses its heat preservation function.
2. The principle of thermos cup is the same as that of thermos bottle. Both of them adopt double-layer shells, and the air between the two shells is pumped out into a vacuum environment. The heat transfer ability of vacuum is very poor, which greatly reduces the convection and conduction of heat energy.
3. Good thermos cup, but it's on the lid. It can be said that the thermal insulation performance of the thermos cup is determined by the thermal insulation performance of the bottle cap. Many common thermos cups are polished inside, which can refract thermal radiation and infrared rays. In this way, the heat energy can be retained in the cup to the greatest extent.
Selection method of thermos cup:
1, the weight comparison shows that the material is better, which everyone should pay attention to.
2. The lid of the thermos cup is very important. It is best to choose a cup made of PC for the lid of the thermos cup, because PC is environmentally friendly and will not produce harmful substances due to high temperature, and other plastic products are not suitable.
3. Observe whether the bottom of Dan in the thermos cup is smooth and has obvious curves. If so, the quality is good.
4. Pour a cup of boiling water into the thermos cup, then cover the thermos cup to see if the surface of the thermos cup will be hot. If you feel that the surface of the thermos cup is very hot, it means that the insulation effect of the thermos cup is poor and the quality is not very good.
5, the material of the thermos cup is very important, especially the inner container of the thermos cup is preferably 304 steel, which can be well insulated and will not produce metals harmful to the human body.