Researsh Of Formation Mechanism Of Opening Bubbles Under Float Glass

The open bubble defects under glass produced in production and the production process were studied,and combining the theory of literature and related experience,several possible mechanisms of float glass tin bath bubbles were mentioned.Experiments are designed to verify the mechanisms and industrial production situation.According to the experimental results and the production situation,the possible mechanisms are treated,retaining reasonable parts and throwing away unreasonable parts,then a reasonable mechanism is obtained.Glass samples with close bubbbles under glass were selected when a mount of open bubble defects appeared in production process and the gas chemical components in these bubbles were detected.The result showed that the main gas caused the open bubble defects was hydrogen.The solubility of hydrogen in tin solution was measured by an indirect measurement method.The experimental results were consistent with the relevant literature values in the changing trend,and the solubility of hydrogen in tin solution increased with the increase of temperature.Using the data that equal the relative values of hydrogen solubility determined by experiment plus the hydrogen solubility value at 600? in related literature to fit the Severt equation and then using the fitting equation to verify the hydrogen solubility values at 600? and 1000? in related literature,the error is no more than 7%.The result shows that the main state of hydrogen in molten tin is atomic state.Paving small pieces of refractory brick at the bottom of a graphite groove to assemble a tin bath and then simulating the tin bath environment to detect the impact of tin bath with different hydrogen permeation on bubble formation.And the result suggests that the refractory brick with low hydrogen permeability has a good inhibitory effect on hydrogen diffusion,while the refractory brick with high hydrogen permeability has a bad inhibitory effect on hydrogen diffusion.And when the external conditions change,the tin bath with low hydrogen permeability is not easy to produce bubbles,while the tin bath with high hydrogen permeability would produce lots of bubbles.The hydrogen bubble formation mechanism of tin bath was obtained by ratiocinating according to the experimental results,the situation of production line,the continuity of temperature distribution of tin liquid and the conditions of bubble formation in tin bath.When the temperature of the tin bath rises,the hydrogen in the bottom space of the tin bath diffuses into the tin liquid through the refractory brick and dissolves in the tin liquid,leading to the tin liquid oversaturated.And the hydrogen atoms in supersaturated liquid diffuse into the opening holes on the surface of refractory brick where bubble cores exist and then two hydrogen atoms recombine into a hydrogen molecular,leading the bubble to become large and finally forming bubbble defect on glass belt.After one bubble is released,it will leave part of the air source in its original position,so that bubbles can be continuously produced until the equilibrium state is reached at that temperature.After cooling down,the gas in the gas space under tin bath is supplemented so that the occurrence of bubble defects would be repeatable.