The thermodynamic treatment of the cryosorption process in a cryopump Available to Purchase

The cryocondensation and cryosorption dominate the whole pumping process in a cryopump. Thus, it is prudent to study the cryosorption phenomenon from the thermodynamic viewpoint to enhance understanding of cryopumping. On the basis of the equilibrium between gas phase and adsorption phase, this paper has tried to deduce the relevant thermodynamic functions involving enthalpy, adsorption heat, entropy, Gibbs free energy, and the interrelations of the various parameters existing in the cryosorption process. These authors established an experimental system by using the ZDB‐150 cryopump with the closed cycle refrigerator, and conducted the experimental study of cryosorption for hydrogen on the ZX‐15 charcoal at the temperature of 18–22 K and in the pressure range of 10⁻⁴–10⁻⁷ Torr. Deducing from the experimental data, the above thermodynamic functions and the relationship among themselves in the cryosorption process were presented. It shows that this work is useful to the investigation of the cryosorption process in a cryopump.