why are there three spots in the thermos?
So hot water bottle contains three black spots, the three small black spots, is a factory specially to fill in three pieces of asbestos. Asbestos elastic, can absorb part of the residual water vapor in the interlayer, increase the efficiency of the thermos of insulation
For thermal insulation, thermos adopt two layers of glass, inside and outside the middle smoke to the air, forming a vacuum heat insulation, and in order to reduce the contact area of two layers of glass, only in the bottle is the joint of two layers of glass, the other parts without contact, in this way, after the tank filled with water, shake from the tank to encounter outside bile, make the thermos damaged, in order to make the two layers inside and outside the force at the same time, increases the three difficult to heat transfer, good elastic rubber material, because it is in front of the silver in the 3 rubber pieces, so after the silver plating on three points not silver plated, we can see three black spots.
This is normal. Vacuum flask is double vacuum, black spots is between two layers of pillar, if there is no black spots, inside because of will not bear water pressure and burst.
