Glass bubbles and causes

the bubbles and causes visible gas inclusions is composed of various kinds of gas bubbles in glass.
the size of the bubbles per cent range from a few millimeters to a few millimeters, the smallest bubble actually called & other; Blub & throughout; , look from the shape, the bubble also has all kinds of; A spherical, oval, and hair, bubble deformation is mainly in the products in the process of forming.
according to different causes, bubbles can be divided into: residual bubbles, the batch of secondary air bubbles, outside air bubble, bubble and refractory metal iron bubble caused by five.
( 1)
residual bubbles with the batch of material when heated to melt to produce a large amount of gas, in order to remove the glass melt in the gas, must be clear, sometimes because of the destruction of the melting system and residual gas inside the glass cannot be released. Raise the temperature, reduce the glass & ndash; — Gas interface surface tension, reduce furnace gas pressure, can promote the bubble overflow. Glass flow has a great influence on bubble overflow, fluid flow can take away, and often prevents bubble overflow, strictly abide by the rules of fusion system is to prevent the decomposition of the batch of the most important measures of bubbles.
( 2) Secondary air bubbles
clear glass with the dissolved gases in the state of equilibrium, if of vitreous conditions changes greatly, has clarified the often found there bubbles and grey bubbles in the glass, because bubble size is very small, glass when the low temperature viscosity is very big, want to eliminate the bubbles is very difficult, so they are a large number of residues in the glass. Residual glauber's salt decomposition also belong to the secondary breakdown phenomenon. In order to eliminate the secondary air bubbles, it is necessary to adhere to the correct temperature system and gas system.
( 3) Outside air bubbles
when loading into the stove, the air contained between particles to the batch of glass melt, in addition, for the broken glass block also contains a certain amount of gas, between all these gases should be removed in the process of clarification, however, the air outside and cooperate with the residual air bubble in the material, will remain in glass melt, the main preventive measures is: use the right amount of broken glass, according to the particles form a correct selection of raw materials.
( 4)
refractory bubbles in the glass and refractory materials, often see inside the glass to gather a lot of bubbles, this phenomenon is caused by the interaction of glass and refractory materials, when the refractory of lead oxide and silicon dioxide dissolves in glass melt, the reaction between the glass and the dissolved gases tend to release these gases and generate bubbles, refractory hole is also often contain gases, these gases because there is no other way out into the glass.
in order to prevent the generation of air bubbles, it is necessary to improve the quality of refractory materials, such as density, glass erosion resistance, mechanical strength, and lower iron content, and they must strictly abide by the melting system, do not make intensified erosion refractory temperature was too high.
( 5) Metallic iron caused by bubble
sometimes because the operation is not careful in the production or negligence, fell into the metallic iron in the glass, the metallic iron gradually dissolve in the glass, the glass coloring, and contains carbon in iron be vaporized into a bubble. In order to prevent the bubble, must be careful preparation, the batch of note in front of the melted YaoChi examination, using good quality metal as baptized into glass molding tool parts.