Semiquantitative Test Method for Degradation Ratio of Vacuum Degree of Vacuum Glazing by Photoelastic Method

Vacuum failure will lead to insulation function failure and increasing huge potential security problems for vacuum glazing, it is necessary to inspect the vacuum degree value of the vacuum glazing in service. In this work, the relationship between the bearing behavior and vacuum degree value of the vacuum glazing was studied by experiment, the experiment results show that the bearing behavior of vacuum glazing showed a greater than 50% reduction after the vacuum degree lose completely in vacuum cavity of the vacuum glazing. One test technique for degradation ratio of vacuum degree of vacuum glazing by photoelastic method was developed in this study. Through linear proportional relationship between support stress spot size and degradation ratio of vacuum degree observed via photoelastic method, vacuum degree completely disappear and stress spot size is 0. So, the ratio R(less than or equal to 1) represent the relative differential pressure between the support stress spot size tested in-situ and the support stress spot size measured in vacuum degree intact environment. The degradation ratio of vacuum degree is (1-R) %. Obtaining qualitative or semi-quantitative assessment of vacuum degree degradation ratio of vacuum glazing through observe support stress spot size with photoelastic apparatus.