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

A testing device based on symmetrical structure is designed to solve the outgassing rate testing problem of less than 10⁻⁸ Pa·m³/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·m³/s～5×10⁻¹⁰ Pa·m³/s.