CFETR堆芯真空室抽气系统的初步设计

根据中国聚变工程实验堆(CFETR)堆芯真空室的尺寸、偏滤器工作气压及抽气要求,模拟计算出低温泵在偏滤器口对燃料粒子的有效抽速约43 m~3/s,运用粒子平衡法计算出堆芯真空抽气所需的低温泵的数量,并验证了氦灰抽除的可行性和分析了低温泵对氚滞留的情况。通过计算堆芯真空室抽极限真空所需要的抽速和前级抽气系统的平均有效抽速,初步设计了维持泵的数量和预抽气的前级泵组。CFETR堆芯真空抽气的初步设计为后续真空系统的工程设计及建造提供了理论依据。     

何氏系数的定义、表达型式及其应用

本文介绍了1932年何增禄先生为了评价扩散泵各种喷咀结构的抽气效率,在他的论文中首先提出了"抽速系数"(Speed Factor)的定义和表达式.这个系数的提出促进了扩散泵性能有很大的提高,结构也有很大的改进.人们为了表彰他这一贡献,将这个系数定名为"何氏系数"(Ho Coefficient).后来人们以泵口直径为标准来评价泵的抽气效率,将这个系数又分别定义为:"何氏系数"为泵的实际抽速与泵体内径与顶喷咀外径之间的环形抽气面积上按分子泻流计算的理论抽速之比;而"抽速系数"则为泵的实际抽速与泵入口断面积上按分子泻流计算的理论抽速之比.这两个系数之间有一定的换算关系.德国学者Jaeckel(亚开尔)和Nller(缪勒)分别又给何氏系数提出了新的表达型式,便于计算.使何氏系数更加完善,在一些高真空泵的设计和改进上得到了广泛地应用.     

HL-2M装置真空室预抽气系统的研制

通过搭建HL-2M真空室整体预抽气系统,对真空室的设计、加工和安装工艺是否达到超高真空技术要求进行了试验检测.采用三套分子泵机组和一套低温泵机组作为主抽系统,对HL-2M真空室进行了预抽,72小时后真空室真空度达到3.7×10-5Pa,超过了预期的预抽真空度.在本底真空度为3.7×10-5Pa的条件下采用静态定容法测试...     

提高旋片泵抽气速率的探讨

前言 旋片式机械真空泵是目前国内外生产和应用较多的一种泵。我们合肥工大真空 专业74级师生,在南京真空泵厂开门办学过程中。在南泵和沈真所领导、工人、工 程技术人员的指导下,对旋片式机械真空泵抽气速率计算公式及有关数据进行了初 步计算和探讨。 一、抽气速率的定义: 在一定压强、温度下,单位时间内泵从被抽容器内抽除的气体体积,简称抽速。常用“S”表示。 1.名义抽速S名: 泵设计时所选定的标准抽速(760乇时旋片泵应达到或稍超过的抽速)。根据部颁标准,我国2X型旋片泵抽速系列有以下九种(单位:升/秒) 0.5、1、2、4、8、15、30、70…     

三级罗茨泵直腰茧形转子型线的研究

三级高真空罗茨泵是一种新型罗茨泵，具有极限真空高、压缩比高的特点．在１０～１０－３Ｐａ范围抽速大，并获得无油真空。用于溅射、离子镀及真空沉积设备等抽气，优于扩散泵和分子泵。     

我国一台大型空间环模设备获得超高真空

我国目前一台大型空间环境模拟设备,直径7米,高12米,容积400米~3。本文简介了超高真空系统的设计和调试情况,容器极限真空度为3.8×10~(-3)托。一、抽气系统的设计通常,大型空间环模室真空获得系统的设计可采用三种方案:早期(六十年代),采用大量的油扩散泵机组,尽量布满容器周围,如美国斯托克公司所研制的一台直径10米的环模室,用17台5万升/秒抽速的油扩散泵机组,容器极限真空为10~(-6)托。我们将此称为第一代抽气系统。第二代真空获得系统,是采用油扩散泵与20K深冷泵的组合抽气系统。由于引进有巨大抽速的深冷泵,抽气时间缩短,处理气体能力增大,极限真空达到10~(-8)托至10~(-9)     

三轴罗茨真空泵的抽气理论和结构设计

新兴行业的不断兴起给真空泵带来了快速发展的机遇,同时也对真空泵的集成化、高效率、节约空间、高技术含量提出了更高的要求。本文提出了一种三轴式的罗茨真空泵,对其抽气过程进行了介绍,并基于啮合原理,给出了一种典型的四叶圆弧型转子的型线方程。通过对抽气过程的建模分析,在抽气效率、压缩比、旋转应力和热变形等方面,与常规的双轴式罗茨真空泵进行了对比。计算和模拟结果表明,在空间尺寸增加不多的情况下,三轴式罗茨真空泵具有接近两倍的抽速、良好的压缩比和更好的动平衡特性的特点,具有较好的技术优势和发展前景。     

提高溅射离子泵抽速的研究

按抽气过程推出了溅射离子泵的抽速公式。实验研究了阳极结构、阴极材料对提高抽速的作用。通过离子泵抽氩清洗后抽速提高现象的分析研究.证实了阴极材料表层成分对离子泵抽速有几倍的影响;钛阴极的泵在抽氮气达到稳定值后,阴极表层即盖满 TiN,而泵的正常抽速是离子溅射 TiN 生成的钛原子在阳极表面抽气提供的。研究表明,理想的离子泵阴极材料不仅应当溅射率高,溅射膜有高的吸气性能,而且应对入射的被抽气体原子有足够高的扩散能力。     

NEG泵抽气性能仿真模拟与测试系统设计

烧结型非蒸散吸气剂(NEG)泵HV400具有对氢及氢同位素有很高的亲和力,即使室温状态下也能发生吸附效应。为了适用于EAST托卡马克中性束注入器工作条件下稳定抽气,针对HV400的抽气性能开展了模拟仿真和实验研究。采用Molflow软件仿真分析了工作状态下不同进气量的压力分布规律与抽气性能,得到了系统平衡压力与进气量以及抽速随着平衡压力而变化的特性曲线,发现三种气体在10^-3～10^-2 Pa时抽速有微小起伏,表明HV400对H₂、CO₂和N₂抽气性能稳定,评估结果与实际抽速相比误差分别为1.95%、3.13%和2.09%,均在合理误差范围内。基于标准化流量计法完成了NEG泵抽速测试系统设计与平台搭建,并进行了抽速性能测试实验,实验结果与仿真模拟都验证了系统设计的可行性,且在10^-3 Pa量级下抽氢效果最好,为NEG泵在中性束注入器的真空系统设计提供了理论依据和技术支持。     

变频调速在大型气冷罗茨真空泵JZJQH2500-224抽气系统中的应用

气冷罗茨真空泵及其机组应用领域十分广泛,在气冷罗茨真空泵组合抽气系统中,至今还未有通过变频控制组合系统的配套功率.本文根据罗茨真空泵消耗功率特性,介绍了如何利用变频调速降低大型气冷罗茨真空泵组合抽气系统的配套功率,并对大容器较快地抽真空.并介绍了变频器与PLC的连接方式.最后比较了采用变频调速的JZJQH2500-224抽气系统与未采用变频调速的JZJQ2500-24系统的不同点.     

Non‐contact vacuum pumps

Non‐contact oil‐free vacuum pumps are widely used in different technological processes such as nanomaterials industry, pharmaceuticals industry, food industry, medicine, etc., thanks to absence of oil seal, high discharge, long operating life, yet low energy consumption. Scroll pumps are of particular interest as they make it possible to isolate bearing assemblies with grease from the working volume of the pump with the help of bellows. Pumping characteristics of non‐contact vacuum pumps are greatly influenced by backward leakage through slot channels of the rotor mechanism. The conductance is the main value characterizing backward leakage. In this paper an efficient method for prompt conductance calculation of slot channels with any geometry with the minimal clearance at a certain point along gas flow direction is presented. The calculation error of the presented method does not exceed 6%. The presented method was used in mathematical models for the pumping process of scroll pumps, claw pumps and Roots pumps. This method is recommended for pumping characteristics calculation of different non‐contact pumps and gas flow rates in vacuum systems channels.     

Abpumpverhalten von Roots‐ und Schraubenvakuumpumpen

Pump down characteristic of Roots pump combinations Combinations of roots pumps and screw type vacuum pumps are often used in industrial vacuum applications because of their high pumping capacity, their compact dimensions and their good energy efficiency. In load lock applications, the type of load control has a high influence on the evacuation time as well as on the energy efficiency of the pump combination. The operation limits of roots pumps are discussed and means to prevent an overload of the pump are introduced.     

200吨级转子高速动平衡试验室真空抽气系统

叙述气冷罗茨真空泵机组应用于大容器的快速抽真空系统,可以提高抽气效率及其节约维修费用以及PLC、Modbus RTU、智能马达控制器等新技术在真空控制系统中的应用.     

关于真空除气使用的真空泵情况分析与讨论

为使真空泵的抽气能力能最大程度适应除气过程,在选用真空泵时需考虑到搅拌气体数量、设备表面放气和设备的漏气率.随着钢液真空处理技术的发展,能保证高效率、有效地脱除钢液中的气体成为迫切的问题.由于抽出气体有灰尘,维修次数多等综合因素,应采用抽气能力大、运转可靠性强、结构简单的蒸汽喷射泵而非机械泵.但近年来,钢液真空处理真空...     

Experimental Study of Oil‐Free Claw Vacuum Pump Characteristics

Experimental study of pumping characteristics of a pilot model of a claw single‐stage vacuum pump with identical rotors was carried out. The curves of pumping speed vs. pressure at different rotary speed and the ultimate pressure at different rotors speed were determined on a test unit. Indicator pressure diagrams in working chambers of claw vacuum pump were obtained with the help of special sensors. Thus, an experimental data bank concerning the pumping characteristics of claw vacuum pump was created. It may be used for estimation of mathematical model adequacy and further development of the pump design.     

油气混和状态真空抽气系统试验初步研究

根据系统抽真空要求,完成管路设计选型与抽空能力计算.针对混和型介质及系统防火防爆的特点,优先选用干式真空泵.通过搭建真空管路系统,针对不同抽速真空泵、不同管路长度、不同抽空容器、不同混和介质开展多组试验.试验结果分析表明,干式真空泵能够满足抽空要求:管路中最小管径的管路长度对抽真空时间有较大影响;在本次试验条件下,环境温度变化对抽空时间有一定影响.     

航天器氦质谱真空容器总漏率检测的灵敏度及可信度探讨

依据航天器氦质谱真空容器总漏率检测原理,讨论了检漏仪和真空容器直接相连、同真空容器主真空泵并联、在前级泵和主真空泵间等连接方式,逐项研究了总漏率测试的最小可检漏率、反应时间,分析各种连接方式的应用特点,认为对大型航天器氦质谱真空容器检漏系统,检漏仪连接在前级泵和主泵之间可得到较好的灵敏度和反应时间.通过测量不确定度的分析与评定,确定一般航天器氦质谱真空容器总漏率检测的相对标准不确定度小于10％.     

Deformations of Working Elements in Oil Free Scroll Vacuum Pumps

The mechanical and thermal causes of deformations of the orbiting and the fixed elements of oil free vacuum pumps are considered. Basic data for deformation calculation are geometric dimensions of the pump and dependence of working chamber volume on the orbiting scroll element rotation angle. Gas temperature and pressure values in each vacuum pump chamber are obtained with the help of a working process mathematical model. Deformation calculation is carried out by the finite element method realized in the software ANSYS. It is shown that deformations caused by pressure‐induced mechanical forces do not have considerable influence on the change of radial clearances between the scrolls. They may not be taken into account for pumping characteristics calculation. Thermal‐induced deformations are much greater, and the change of the clearances due to this cause may be 25 % and even larger.     

Verhinderung von Ölrückströmungen in Wälzkolbenpumpen

Prevention of oil backflow in Roots pumps - Residual gas analysis by quadrupole mass spectrometry In industrial vacuum applications too, there is a growing trend towards dry, oil-free, pump systems. But what does oil-free mean? All bearings and gearboxes used in roots and screw pumps require lubrication with oil or grease. While constructive measures are implemented to avoid contamination of the process gas by back-flowing lubricants from the pumps, no tests have yet been carried out on complete pumping stations to confirm their effectiveness. With the help of this report it is possible for the first time to make qualitative statements about the oil-free nature of dry pumping stations.     

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.