1、前言 近十几年来,油扩散泵在工艺上已有了显著的发展。近来,不使用液氮冷阱可获得10-9托的极限真空度,同一口径的泵抽速几乎提高了一倍;最大允许反压强及最大流量也大幅度地提高了,泵入口处工作液返油率已降低到10-3毫克/厘米2·分左右。 扩散泵性能的这些提高在很大程度上 1, Preface In recent ten years, the oil diffusion pump has made significant progress in the process. Recently, the ultimate vacuum of 10-9 torr can be obtained without using the liquid nitrogen cold trap, and the pumping speed of the same caliber is almost doubled. The maximum allowable backpressure and the maximum flow rate are greatly increased. The working fluid at the inlet of the pump The rate of return has been reduced to about 10-3 mg / cm2. These improvements in diffusion pump performance are to a large extent