一、前言 从宇宙开发到食品加工的广阔领域里都离不开真空技术,尤其是在化工、医药、食品及电工材料的真空浸渍、真空冷冻干燥等工艺过程中,排出的气体主要是水蒸汽及其它可凝性蒸汽。其工作真空度多为10～(-1)～10～(-3)托。国外通常用罗茨泵与油封机械泵组合进行抽气。为此, I. Introduction From the development of the universe to the vast field of food processing are inseparable from the vacuum technology, especially in the chemical, pharmaceutical, food and electrical materials, vacuum impregnation, vacuum freeze-drying process, the gas is discharged mainly water vapor And other condensable steam. The working degree of vacuum for the more 10 ~ (-1) ~ 10 ~ (-3) care. Pumps and oil seal mechanical pumps are commonly used in foreign countries to pump gas. to this end,