Selected thermos bottle how to hear?
An outer glass broken inside, the inner glass bravery also issued a "buzzing" sound, it is of the bile in the convection of air inside the sound..Good thermos buzzing sound, sound is bigger, the better
Ears close to the bottle mouth, feeling of suction, buzzing sound is good
3, check whether the silver plating is uniform, because silver plated to avoid the thermal radiation, prevent heat loss. 4, to see if the thermos bottle mouth round, inserting the cork is tight or leak. People usually choose listening thermos, this is unscientific. An outer glass broken inside, the inner glass bravery also issued a "buzzing" sound, it is of the bile in the convection of air inside the sound
1, look at the bottom of the inside side of tail gas is complete. If the tail gas breakdown or was knocked off, belong to the damaged goods, because inside is two layers of glass, no air, tail gas damage that has been in the air, no heat preservation effect. 2, a finger gently knock inside place of glass, if the sound is ringing, good inside is no crack.
