Research On Pumping Of Vacuum Glazing

As the extremely superior performance in thermal insulation and heat preservation, as well as its good noise reduction performance, Vacuum glazing become a wonderful transparent material for making doors and Windows. In order to overcome the disadvantages of the traditional vacuum glazing, the production process of vacuum glazing is improved. However, the unreasonable process parameter in the new technology limits the vacuum glazing production efficiency. In order to product vacuum glazing faster and better, the optimization of process parameters is imperative.In this paper, the pumping link of new type vacuum glazing production process is studied through software simulation. Research content contains the main two parts in pumping process:the molecular flow state and the viscous flow state. The main optimization parameter in the research is glass plate spacing in pumping process.The CFD method is used for transient simulations in study of pumping process under viscous flow state. By comparing the simulation results we concluded the influence of distance between the plate in pumping process:When plate spacing is greater than 0.4 mm, the influence on the pumping process is little, while the plate spacing change from 0.4 mm to 0.3 mm, there was a dramatically increase in pressure difference between the flow area center and edge relative to other plate spacing. At the same time, the pressure drop speed on air flow area center point slows down significantly. So the plate spacing of 0.5 mm is the better process parameter concluded from simulation results in combination with the height of the support.The molecular tracking model used in Monte Carlo method is used for reference in research on pumping process under molecular flow to obtain the distribution of time molecules used during flying out of valley. Molecular tracking process needs corresponding mathematical model and then the help of Matlab software for program simulation. Pressure-time function P (t) is deduced using flight time distribution results combined with the existing theory which describes the pressure in valley changing with time. Conclusions are obtained through P(t) s of different plate spacing:under the molecular flow regime, pumping rate began to drop sharply if the plate spacing is less than 0.5 mm,while if the plate spacing is more than 13 mm, the hinder effect on pumping process of glass plates is little. So the glass plate spacing should be greater than 0.5 mm when pump under molecular flow regime.Combining with the results from two parts of research we concluded:1. Add pumping pipeline for coarse vacuum and the aperture is located in at the center of the longer side of vacuum chamber.2. For vacuum glazing whose support height is 0.5 mm, set the glass plate spacing is 0.5 mm in pumping process, it means the two glass plate keep good contact with and seal immediately after pumping.