漏率公式与判据和内部气体含量的分析研究(二)

Analysis and Research on Leak Rate Equations,Failure Criteria and Internal Gas Concentration (2)

在对氦质谱细检漏漏率公式的分析和对密封腔体内外气体交换过程公式的推演中,以氦气标准漏率LHe代替等效标准漏率L,引用了氦气交换时间常数τHe,使公式更为真实和简单直观。通过漏率偏差的分析和内部气体含量的计算表明,能够应用本文的公式对密封腔体内外气体的交换过程进行工程计算。计算分析了现行我国国家标准和美国标准各种试验条件漏率判据所对应的τHe,着重指出漏率符合接收判据并不能有效保证内部水汽含量要求。讨论了这些标准中进行的改进、存在的密封性等级及进一步改进的必要,并提出了建议进行研究的内容。

Analyzing the mathematical equations on helium mass-spectrometer-type fine leak test and the exchange process of gases between package cavity and environment, this article illustrates the method of employing helium standard leak rate τHe instead of equivalent standard leak rate L which is imagic. The introduction of the time constant τHe makes the equations in the article more practical to be utilized and easier to be understood. The analysis of leak rate deviation and the calculation of internal gases concentration have proved that the equations in the article could be used in engineering to calculate the process of the exchange of the gases between hermetically sealed package cavity and the environment. Different time constants τHe scorresponding to the failure criteria in various test conditions of leak rate test in both national military standard and America military standard are calculated and analyzed. Those that are acceptable in the leak rate test are not sure to meet the demand of internal vapor concentration. Some improvements in the contemporary standards are discussed such as hermatization grade. The article puts forward the proposal that there exists the necessity that some part of the contemporary standards should be further improved and points out the prospectus that should be further examined.