The model of a cryogenicentrapment pump is selected mainly accrding to the water vapor evacuation rate and the capacity of the vacuum chamber and the refrigerating coil in the vacuum chamber Generally speaking ,the longer the pipeline is,the higher the gas entrapment speed will be .Normally, the evacuation rate we recommend can be 4 times higher than the current evacuation rate,as aresult of which,the vacuum evacuation time will be shortenedby30%~80%,Once the general specification of the cryogenic entrapment pump and the surface area of the refrigerating coil are determined,the temperature and refrigerating capacity can be calculated according to the additional thermalloads(e,g,the heat in the connecting pipeline or in the production process).