Manufacturing process of vacuum flask

- Jun 19, 2020-

Manufacturing process editor

The core component of a vacuum flask is its bladder. The following four steps are required for the manufacture of bottle bile:

Bottle preform preparation

The glass material used for vacuum flask belongs to sodium calcium silicate glass commonly used. Take uniform and impurity free high temperature glass liquid and blow it into the inner and outer glass preforms with wall thickness of 1 ~ 2mm respectively in the metal mold (see glass manufacturing).

Making bile billet

The inner bottle is placed in the outer bottle, the mouth of the bottle is sealed as a whole, and the bottom of the outer bottle is provided with a catheter for silver plating and air extraction operation. There are three kinds of glass bottle blank: bottom drawing sealing, shoulder shrinking sealing and waist sealing. The bottom sealing method is to cut the opening of the inner bottle preform and the bottom of the outer bottle preform, put the inner bottle into the bottom of the outer bottle and fix it with asbestos plug pad, then close the bottom of the outer bottle, connect the small tail tube, and fuse the two bottle mouths. The method of shoulder reduction sealing is to cut the opening of the inner bottle preform and the outer bottle preform, put the inner bottle into the upper end of the outer bottle and fix it with asbestos plug pad, shrink the outer bottle shoulder and fuse the two bottles, then connect the small tail catheter. The waist sealing method is to cut the opening of the inner bottle preform and the outer bottle preform and cut the waist into two sections, put the inner bottle into the outer bottle, fuse the waist again and connect the small tail catheter.

Silver plated

A certain amount of silver ammonia complex solution and aldehyde solution as a reducing agent were injected into the interlayer of the flask billet through the small tail tube for the silver mirror reaction. The silver ions were reduced and deposited on the glass surface to form a silver mirror film thin layer.

vacuum

The liner of the silver-plated double billet is connected with the vacuum system, and heated to 300 ~ 400℃, which causes the glass to release all kinds of adsorbed gases and residual moisture. At the same time, the vacuum pump is used to extract air, and the vacuum degree of the interlayer space of the bottle bladder is up to 10-3 ~ 10-4mmhg.