摘要
为解决在假密封源氦加压检漏技术中存在的问题,明确计算公式和检验方法,本研究利用分子流状态下漏率与温度、样品尺寸、漏孔两侧高低端压力的计算公式,推导得出假密封源的氦加压检漏公式。对推导后公式研究发现,通过指示漏率R计算实际标准漏率L时具有双值特性,须在细检漏后再进行粗检漏以排除大漏孔的存在;GB/T15849给出的计算公式为氦加压检漏公式在满足一定条件下(t_(1)和t_(2)<<P_(0)×V/L)的简化公式,直接使用会放大拒收点,导致结果错判。本研究讨论了在不同内腔体积和合格漏率条件下加压压力、加压时间和净化时间对拒收点的影响,结果表明:增大加压压力、延长加压时间以及缩短净化时间能够提高指示氦泄漏率R,从而提升检漏灵敏度,且当净化时间影响较小时,加压压力和时间需满足PEt1≥QP_(0)^(2)V/L^(2)。给出了氦加压检验试验条件选择原则。
In order to solve some problems existing in the helium pressure leak detection technology of the pseudo-sealed source and clarify the calculation formula and test method,the paper deduces the helium pressure leak detection formula of the pseudo-sealed source by using the calculation formula of leakage rate and temperature,sample size and,and high and low pressure on both sides of the leak hole under the state of molecular flow.Through the research of the derived formula,it shows the actual standard leakage rate L is characterized by double value when the indicating leakage rate R is used to calculate the actual standard leakage rate L.It is necessary to carry out crude leakage detection after fine leakage detection to eliminate the existence of large leakage holes;The calculation formula given by GB/T15849 is the simplified formula of helium pressure leak detection formula under certain conditions(t_(1 )and t_(2) P_(0)V/L).Direct use will magnify the rejection point and lead to misjuded results.In this paper,the influence of pressure,pressure time and purification time on rejection points under different cavity volume and qualified leakage rate has been discussed.The results show that increasing the pressurization pressure,prolonging the pressurization time and shortening the purification time can improve the indicating helium leakage rate R,so as to improve the leak detection sensitivity.When the influence of purification time is small,the pressurization pressure and time should meet PEt1≥QP_(0)^(2)V/L^(2).and the selection principle of helium pressure test conditions is provided.
作者
徐卓
史晨钟
马妍
张云
XU Zhuo;SHI Chenzhong;MA Yan;ZHANG Yun(HTA Co.,Ltd.,Beijing 102413,China)
出处
《同位素》
CAS
2024年第3期280-287,共8页
Journal of Isotopes
关键词
假密封源
氦加压检验
检漏公式
粗检漏
细检漏
dummy sealed source
Helium pressure test
formula for leak detection
gross leak detection
fine leak detection