一种基于对称结构的固体材料放气率测试装置设计

Design of a Testing Device for Outgassing Rate of Solid Materials Based on Symmetrical Structure

为了解决小于10-8Pa·m^(3)/s的固体材料放气率测试问题,设计出一种基于对称结构的测试装置。通过对称结构的两个相同真空室分别作为样品室和空载参考室,避免了采用一个真空室先后分别测量空载时本底放气和放置样品后放气重复过程及引入的较大测量偏差;采用耐高温特殊石英材料制成的低放气率真空室,为实现放气率比较小的固体材料测试解决了真空室本底放气的限制条件;设计出用同一台真空计通过转换气路分别测量样品室和空载室内压力的对称结构,避免了原有动态流量法采用两台真空计分别测量时由于灵敏度的差异而引入的较大偏差;装置集成了标准气体流量计用于真空计的在线校准,提高了测量结果的准确性;采用的对称结构陶瓷加热炉,对样品实现25℃~1000℃范围的加热,设计的装置对材料放气量的测量范围为5×10^(-6)Pa·m^(3)/s~5×10^(-10)Pa·m^(3)/s。

A testing device based on symmetrical structure is designed to solve the outgassing rate testing problem of less than 10^(−8) Pa·m^(3)/s.In order to avoid larger measurement deviation due to the use of a vacuum chamber to successively measure the background outgassing at no-load and on-load,two identical vacuum chambers are placed symmetrically on both sides of a vacuum gauge,one as the sample chamber and the other as no-load reference chamber.The vacuum chamber with low outgassing rate is made of special high-temperature-resistant quartz material,therefore the vacuum chamber can test solid materials of low outgassing rate.A symmetrical structure is designed to measure the pressure in the sample chamber and the no-load chamber respectively with the same vacuum gauge by changing the gas path,which avoids the larger deviation caused by different sensitivity of two vacuum gauges when the dynamic flow method is adoped.Moreover,the device integrates a standard gas flowmeter for the on-line calibration of the vacuum gauge,which improves the accuracy of the measurement results.A pair of ceramic heating furnaces are used to heat the sample chamber and reference chamber at the same time in the range of 25℃~1000℃.The measuring range of the designed device for material outgassing is 5×10^(−6)Pa·m^(3)/s~5×10^(−10)Pa·m^(3)/s。