Measurement Platform For Outgassing Rate Of Insulation Materials

Along with the development of cryogenics industry in China,demand of liquid oxygen,liquid nitrogen,liquid hydrogen and liquefied natural gas(LNG)keeps growing,as well as demand of cryogenics storage and transport vessel.Therefore,insulations of cryogenics vessels are required to perform better with the growing demand.Outgassing is one of the critical characteristic affecting high vacuum insulation performance.Based on GB/T 31480-31480,an outgassing rate of insulation materials test platform is built.Design of the test platform,vacuum system design and calculation of the selection,control system,and other auxiliary test equipment selection are discussed in the paper.An outgassing rate test is conducted after platform is set up with a test cavity.The baseline outgassing rate is 1.5?10-8Pa?m3/s,which satisfies design requirements,was achieved.Using constant volume method,outgassing rates of three kinds insulation materials like aluminum foil +glass fiber paper,glass fiber paper,and aluminum foil were investigated respectively.Experimental results show that aluminum foil + glass fiber paper and glass fiber paper outgassing rate significantly decreases with the increase of extraction time,the former outgassing rate decreased from 2.24?10-7Pa?m3/s to 6.06?10-8Pa?m3/s,as well as the latter outgassing rate decreased from 1.24?10-6Pa?m3/s to 4.86?10-7Pa?m3/s.The outgassing rate of aluminum foil is almost zero.Mass spectrometer analyses showed that the gas composition inside outgassing are H2 and H2 O.The outgassing rate test platform and gas composition of mass spectrometry analyses could be applicable for future thermal insulation materials,and support design of cryogenic vessels and provide important data for the selection of insulation material.