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介绍了用于扩散泵低压端双级径向流分子泵详细结构、性能预示及性能测量。性能预示的基础是自由分子流和扩散反射的概念。就现有设计所采用的叶片与环的厚度值来讲，我们认为必须考虑到这些厚度对于泵性能的影响。预示了压强比及速度系数，几乎与转子速度成指数关系并取决于前级泵抽速及气体载荷的程度。 这次研制的泵，转子转速每分钟为３４００转，预示着它的抽速大约为作为前级泵的扩散泵对于氮和空气的抽速的１４及１０倍。预示的性能大体上在实验误差范围内与测得的性能是一致的。 如果人们想在较高的流率下设计适度的压强比，为了（ａ）对于给定的系统医强来说．增加扩散泵的抽气量，（ｂ）对于给定的扩散泵抽气量来说，降低系统的压强，那么就可以在扩散泵的低压端采用径向流涡轮分子泵。
The detailed structure, performance prediction and performance measurement of two stage radial flow molecular pump used in diffusion pump are introduced. The basis for performance prediction is the concept of free molecular flow and diffuse reflection. In terms of the blade and ring thickness values used in existing designs, we think it is important to consider the effect these thicknesses have on pump performance. Predicting the pressure ratio and velocity coefficient, which is an exponential relationship with the rotor speed and depends on the degree of pumping speed and gas load of the foreline pump. The pump developed at this time had a rotor speed of 3400 rpm, indicating a pumping speed of about 14 and 10 times the pumping speed of the foreline pump for nitrogen and air. The predicted performance is generally consistent with the measured performance over the experimental error range. If one wants to design a moderate pressure ratio at a higher flow rate, for (a) for a given system strength. Increasing the bleed pump’s bleed volume, (b) Reducing the system pressure for a given bleed pump bleed, then a radial flow turbopump can be used on the low pressure side of the bleed pump.