The reason why the temperature of cryogenic storage tank is getting lower and lower

Pearlescent sand deflates. The evaporation of low temperature storage tank increases and the vacuum degree decreases. It may be the cause of pearlite outgassing. Pearlescent sand has certain particle size and temperature requirements when filling. When the particle size and temperature of pearlescent sand are inappropriate, after running for a period of time, pearlescent sand will release water vapor, reduce vacuum degree and increase evaporation.