油蒸汽流泵的抽速表达式

通常将油扩散泵和扩散喷射泵(油增压泵),统称为油蒸汽流泵。其工作原理与涡轮分子泵相似。在涡轮分子泵中。由高速旋转的叶片带走气体分子,以完成抽气过程。而在油蒸汽流泵中,抽气过程是由各级喷嘴吹出的高速蒸汽射流,把被抽气体(空气)分子携带到前级压力端。实践证明,无论是涡轮分子泵、油扩散泵或扩散喷射泵,在其相应压力范围内,都具有平滑的抽速特性曲线。 多年来各国学者已对油蒸汽流泵的抽气过程,进行过深刻的分析和讨论。最近德国学者M.Wutz更从气体动力学的角度来探讨油扩散泵的机理,提出了泵的何氏系数的计算表达式。国内许多专家…     

油扩散泵两种抽速测量方法的比较

本文提出了介绍油扩散泵两种抽速测量方法的比较研究。所使用的方法是试验罩法和带有辅助抽气系统的流导管法。这个辅助抽气系统是在流量低于 １０－５Ｎｍｓ－１（～０．１μｌｓ－１）时的很低压力下使用。人们发现为了得到在重叠压力范围用两种方法测量油扩散泵抽速比较结果，当规管距泵口法兰是Ｄ／２时，即得到泵本征抽速的试验罩法的同样位置，流导管法中的流导管应安排在距泵口１．２Ｄ的高度。     

油蒸汽流泵的抽气量和它所需的蒸汽喷射量之间关系的探讨

本文根据气体分子碰撞理论，讨论了油蒸汽流泵的蒸汽射流中起抽气作用的油蒸汽分子在流动过程中与空气分子之间的碰撞次数。求出了泵的抽气量与它所需的各喷嘴蒸汽喷射量之间的数量关系。     

变截面矩形槽牵引分子泵二维抽气理论的研究

本文对牵引分子泵抽气机理进行了深入分析，考虑了通道返流和工作间隙泄漏对泵抽气性能的影响。采用有限差分法对通道内气体分子宏观运动速度分布进行了计算，提 出了牵引分子泵二维抽气理论。     

扩散泵用定压法测量抽气速率计算公式的探讨

用定压法测量扩散泵的抽气速率是目前各国从事扩散泵研究和生户的工作者所接受和使用的一种方法,而其在测量时所引起的种种误差已做了许多研究和探讨（１）。但本文则对在不同温度下所进行的抽气速率测量和滴管内由于油柱上升而引起的计算误差加以分析最后推荐较合理的,简便的扩散泵用定压法测量抽气速率的计算公式。     

轴流分子泵研究(四)──关于单叶轮在过渡流区域内的抽气特性

1.引言 为阐明轴流分子泵的抽气机理,笔者不久前曾对轴流叶轮在分子流区域内的抽气特性进行了研究(1)(2)。 在用油扩散泵作前级泵时,前级真空端的真空度要保持在10～(-4)乇以上,这时构成轴流分子泵的全部叶轮就可以认为形成分子流。但是若只是用油旋转泵作前级泵时,前级真空端的真空度则变为10～(-3)～10～(-2)乇。其结果,据我们推测,在构成轴流分子系的叶轮中靠近出气侧的几个叶轮上,气体分子之间的碰撞次数等于叶板与气体分子之间碰撞次数,即变成所谓的过渡流状态。关于过渡流区域的研究甚少,对它怎样处理目前还没有一个准确的方法。 Scb…     

一种新型的扩散泵喷咀

本文以气体动力学理论为基础，论述了如何通过改进扩散泵的第一级喷咀来提高扩散泵的抽气速率。     

油蒸汽流泵设计的实践与认识

本文内容有二，第一部份根据德国学者Ｒ．亚开耳的《汽流高真空抽气机的理论》的二次近似计算的比抽速的表达式，考虑到扩散面积和喷咀角度对抽气速率的影响，而建立和求解偏微分方程组，推导出扩散泵在最佳抽气速率时的喷咀出口直径和喷咀角度的近似计算公式，可以用作油扩散泵喷咀设计计算的参考。第二部份简要介绍了按动量交换原理所推得之蒸汽量及喷咀喉部面积计算公式的两种表达式和按理想气体状态方程所推得之蒸汽流泵喷射级扩压管之喉部面积计算公式以及扩压管入口直径计算公式。最后提到多级蒸汽流泵各级串联工作的变流量设计问题。     

径向流涡轮分子真空泵

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。     

油扩散泵的工况分析与结构设计

在泵口压强为１０－４～１０－３托时，油扩散泵的抽速明显下降，而扩散喷射泵（油增压泵）尚未有效地发挥作用，形成薄弱区段．因此研制在高压强端抽气能力较强的油扩散泵，将能弥补这段不足，从而为真空应用设备在高压区段大量排除气体，提供理想的抽气设备．     

喷嘴角度对水银扩散泵抽气性能影响的DSMC模拟研究

扩散泵由于其大抽速、连续稳态工作的优点,有望应用于未来聚变堆的偏滤器抽气系统中,以降低目前托卡马克装置中广泛采用的捕集式低温泵所带来的高氚存储量问题。由于氚相容性的限制,目前的商业油扩散泵无法直接应用于聚变堆中,水银将是理想的扩散泵工作介质。为了支持未来聚变堆偏滤器抽气系统的水银扩散泵设计,需要针对水银扩散泵开展设计优化研究。本文采用直接模拟蒙特卡洛方法,基于KT-150扩散泵结构,研究了喷嘴角度对水银扩散泵的抽气速度及水银返流率的影响。结果表明喷嘴角度为45°时能够达到最佳的抽气速度1.53m^3/s,同时返流率没有显著提升。     

Das Vakuumsystem der TOSKA-Spulentestanlage

Plasma confinement in fusion reactors requires large magnetic fields which are generated by superconducting solenoids. The coils of the future reactor ITER have a size of some 18 m × 10 m. Their construction is a technical challenge: the body of the coil suffers from large mechanical forces, originating from the magnetic field, as well as substantial thermal stress resulting from the cooling to 4.2 K. Nevertheless, the coils are required to be absolutely vacuum tight since no loss of the refrigerant helium is permissible. In the Research Center Karlsruhe (FZK) prototype coils are tested in operation under high vacuum conditions. The test chamber has a volume of 170 m³. It is pumped by an oil diffusion pump with a nominal pumping speed of 16 000 l/s. As fore and roughing pumps, a combination of Roots and rotating vane pump are employed. The available effective pumping speed of the oil diffusion pump has been measured by two different procedures: via the resulting equilibrium pressure in case of an injected stationary gas flow, and via the time-dependent decrease of pressure during pump-down. The measurements give an effective pumping speed of some 2 000 l/s. The main reason for the small pumping speed (as compared to the nominal value) is the small conductances of the inserted vacuum components and baffles. When the heating power of the oil diffusion pump is reduced to one half, the pumping speed decreases only slightly, whereas the maximum throughput decreases to one third.     

Using the Edwards 9B3 diffusion pump for circulation in a dilution refrigerator

Problems with the oil cracking have been encountered in using the Edwards 9B3 diffusion pump with Edwards 200 grade pump fluid. These have been solved by using a different fluid, reducing the power to the heater without a loss of pumping speed and by constructing a more effective cold trap.     

镀膜设备真空系统主泵的配置

真空系统是真空镀膜设备的主要组成部分,其主泵的选择对真空性能影响很大,真空镀膜设备的发展要求真空性能清洁无油,动态抽速大.传统的以油扩散泵为主泵的设备不能满足要求,本文叙述了油扩散泵、分子泵及低温泵的特点及北京北仪创新真空技术有限责任公司开发以分子泵及低温泵为真空系统主泵的镀膜设备情况.     

Comparison of two pumping speed measuring methods of oil diffusion pumps

This paper presents a comparative study of two pumping speed measurement methods recommended for oil diffusion pumps. The methods used are the test dome method and the conductance tube method with an auxiliary pumping system which is used at very low pressures when the throughput is below 10^?5 Nm s^?1 (～ 0.1 μl s^?1). It is found that, in order to obtain the comparative results in the overlapping pressure region on the speed measurement of oil diffusion pumps by these two methods, the conductance tube in the conductance tube method should be located at a height 1.2 D from the pump mouth when the position of the inlet gauge is at a distance D/2 from the pump flange, i.e. at the same position as recommended in the dome method to obtain the intrinsic speed of the pump.     

新型K-800A高真空油扩散泵的研制

介绍了新研制的高真空油扩散泵在拓宽抽气速率范围、提高临界前级压力、降低返油率方面的创新设计。给出了新研制的K-800A高真空油扩散泵各项技术指标的实测结果。     

蒙特卡洛法在HIRFL-CSR钛升华泵设计中的应用

介绍了用蒙特卡洛法计算HIRFL-CSR钛升华泵对于不同气体吸附系数在分子流条件下的吸附概率,并分析了挡板的形状、位置设置对于吸附概率的影响.通过实验测试,发现HIRFL-CSR钛升华泵对H2的抽速与计算值接近,证明用蒙特卡洛法模拟计算、设计钛升华泵是可行的.     

对油封机械泵一些主要性能的分析

该文介绍了油封机械泵的抽速与入口压力的关系、泵抽气效率下降的原因,指出泵入口管道的流导和油蒸汽逆流是造成泵抽速下降的主要原因.其次,还对油封机械泵的消耗功率与入口压力的关系进行了分析,指出最大功率时所对应的入口压力,同时还对泵油温度对功率的影响作了分析;给出对泵油性能的要求.     

A new energy-efficient approach to high vacuum pumping

Recent experiments have shown that an efficienty trapped mechanical rotary pump operating with completely degassed oil is capable of pressures in the 10^?7 mbar range. By greatly enlarging the zeolite trap and mounting it immediately adjacent to the work chamber it can be made to funtion simultaneously as a high speed sorption pump for vapours. Outgassed vapours from the work chamber and vapours originating from the pump oil are both pumped by the zeolite. The zeolite is operated at room temperature except during bakeout and is maintained at very low surface coverages to obtain corresponding low equilibrium pressures of water and hydrocarbons. Gases which are not sorbed by the zeolite are pumped by the mechanical pump. Vapour pumping continues for periods of months even when all power to the system is shut down. High vacuum is attainable within a few minutes after reapplying power. If desired, the zeolite can be cooled to raise the pumping speeds for all gases to approximately those for vapours, and to reduce ultimate pressures to the 10^?8 mbar range. This principle can be used as the basis for practical pumping systems which provide clean high vacua with low power consumption. Two pumping stations with speeds for vapours in the 12/s^?1 and 400ls^?1 range, respectively, are discussed.     

Der Beginn einer Erfolgsgeschichte

The beginnings of a successful story The exciting invention of the molecular Pump by Wolfgang Gaede was followed by his new ‘Device of Producing High Vacua’ in 1913. It was announced in the second edition 1913 of E.Leybold's cataloge. Three years later Langmuir in the USA presented a similar pump called ‘condensationpump’, but with clearly better pumping speed. Another design of a pump with two stages was invented by Prof. Volmer in Berlin. Other European companies announced similar pumps. Because Gaede claimed the prinziple of evacuating gas by diffusion, he and Leybold succeeded in making all of them to ask for licences. Respective to Langmuir they exchanged licence to each other. By the time this ‘diffusion pump’ was produced from metal instead of glas, and used special mineral oil, not mercury. In the middle of the 20.century it became a most important tool for creating high vacuum, available with a few liters per second to some thousend liters of pumping speed.