真空计量的新进展

真空计量学已发展成为计量学的一个新的独立分支，其研究内容已从传统的全压力测量与校准扩展到分压力测量与校准、气体微流量(漏率)测量与校准。本文描述了这三个方面的最新进展，从中可看出真空计量学的现状与发展趋势。     

比较法真空规校准装置性能研究

比较法真空规校准装置是真空计量的主要工作标准,主标准器溯源到静态膨胀式真空标准装置。为了保证量值传递数据的准确可靠,对装置的不确定度进行了分析和评定,同时对装置的计量性能稳定性和重复性进行了测试和研究。     

Ensuring primary realization of pressure unit in the vacuum range without typically utilized static expansion system

After the break-up of Czechoslovakia in 1993 the primary metrological standards authority almost fully remained in Slovakia. So we had to build our primary vacuum metrology anew. But we could do it using uptodate techniques that are more effective and they enable us to fulfil our task more effectively and in a shorter time.The steady demand to widen the lower pressure range and a steady demand for maximal accuracy collide with the financial possibilities open to a small country. So it is impossible to follow the classical pattern for the vacuum standards: liquid columns, static expansion system and dynamic expansion system. But it is possible to utilize contemporary progress in construction of piston manometers. This enables us to discard liquid column and static expansion techniques in favour of piston technique [Tesar J, Prazak D. Vacuum 2002; 67: 311, Tesar J, Prazak D, Krajicek Z. In:Proceedings of international symposium on Pressure and Vacuum, 2003. p. 169, Tesar J, Repa P, Prazak D, Krajicek Z, Peksa L. Vacuum 2004; 76: 491.]. Such system fulfils all the needs of a little industrial country and is economically acceptable.     

真空计量的现状及发展趋势

介绍了真空计量、真空计量标准、真空测量与校准技术、空间真空测量等方面的内容.基于真空计量的现状,提出了真空计量的发展趋势.     

Mit Nichts in die Kälte

With nothing into the cold – Dilution cryostats and vacuum equipment for quantum computers Dilution cryostats are used for various applications, for example on a large scale for the development of quantum computers, or for basic research in solid‐state physics. Vacuum technology plays a central role in generating the low temperatures. This article highlights the necessary features of vacuum pumps that circulate the so‐called ³He/⁴He mixture. In addition to the results of a field test with a multistage Roots pump, the use of pumping systems is discussed.     

真空冷却过程中水分蒸发沸腾的数值模拟（Ⅰ）：模型的建立

真空冷却过程是复杂的相变传热传质过程。在真空冷却期间,当真空室内的真空压力低于或者等于熟肉温度对应的饱和压力时,熟肉内部的水分将会沸腾蒸发以产生冷却效应。在能量和质量守恒的基础上,经过适当的简化,建立了真空冷却过程中水分迁移的数学模型。此模型能够预测真空冷却过程中熟肉内部的温度、压力和水分含量分布。     

甘露醇冷冻干燥室内真空压力特性的研究

冷冻干燥室的真空系统为冷冻干燥提供了真空环境,真空压力特性对冷冻干燥过程顺利进行至关重要,本文以甘露醇溶液的冷冻干燥过程为例,从三个方面对冷冻干燥室内真空压力特性进行了研究:一、真空度对冷冻干燥物料质量称量的影响;二、真空度对冷冻干燥物料瓶内温度的影响;三、真空度对冷冻干燥物料一次干燥速率的影响.通过实验,得出结论:真...     

VAKUUMWAAGEN Teil 1: Einleitung und Makrowaagen

Balances destined for weighing of goods in vacuum are labeled as vacuum balances. Macrobalances are designed for loads above 100 g. For comparison of mass prototypes without influence of buoyancy, vacuum mass comparators were designed. Large vacuum balances are used for the determination of the specific or the atomic mass of gases. Electromagnetic vacuum precision balances are used to investigate chemical reactions at reduced gas pressure and for thermogravimetric analysis. Production processes can be controlled by means of load cells of various design.     

Vakuummessung im Wandel der Zeit

Vacuum Measurement over the Course of Time — From Torricelli to bakeable digital wide‐range sensors for measurement from 10³ to 10^‐12 mbar Since the first vacuum measurement in the middle of the 17th century, various methods have been developed to measure total vacuum pressures. After establishing the kinetic theory of gases in the late 19th century, the development of different indirect measurement methods started. Hereby, the lower detection limit — located in the fine vacuum range for direct methods such as mercury tubes — has been continuously shifted down to the ultrahigh vacuum range. The combination of different measuring principles in wide‐range sensors soon allowed the measurement over extended pressure ranges — with just one device. Latest developments have yielded to the creation of a new generation of vacuum measurement: passive bakeable wide‐range sensors. Consisting of optimized ionization‐sensors and a novel integration of a digital Pirani principle, they are the first vacuum sensors for precise total pressure measurement over 15 decades — from atmosphere down to the ultra‐high vacuum (10⁺³ to 10^‐12 mbar).     

真空冷却过程的机理分析

真空冷却过程是复杂的相变传热传质过程,该过程涉及到扩散、传热、传质和相变等机理.在能量和质量守恒的基础上,经过适当的简化,建立了真空冷却过程中的数学模型.通过对结果分析发现,数值模拟的结果与实验数据吻合很好,误差在5%以内.数学模型可以准确预测真空冷却过程中的温度变化和质量损失,将有助于进一步理解和研究真空冷却机理.     

Die Entwicklung der Turbomolekularpumpe innerhalb der letzten drei Jahrzehnte

Development of turbomolecular pumps within the last three decades On the occasion of the 30^th anniversary of the “Vakuum in Forschung und Praxis” in 2018, the author puts the turbomolecular pump at the centre of the historical overview. From the first experiments, which led to the development of this key component of modern vacuum generation in high and ultra-high vacuum technology, to further developments up to the present day, individual technological advances made by Pfeiffer Vacuum – especially those of the last 30 years – are presented and future development trends are shown.     

蔬菜真空冷却工艺的实验研究

真空冷却是一种能提高果蔬贮藏品质并可延长货期的快速预冷方法。本文以卷心菜、大葱、豆角和韭菜为研究对象,利用BSVC5真空预冷机,针对加水、包装、降压和复压等工序进行实验研究。结果表明,真空冷却前对蔬菜加水和包装能够明显加快冷却速度和降低失重率,且加水量应低于6%;采用分阶段降压能使蔬菜降温更均匀,并根据蔬菜自身性质终压应控制在200～750 Pa范围内,采取引入冷空气复压的方法可以避免蔬菜温度回升。     

Vacuum metrology and its impact on research and industry

By accurate vacuum measurement, it is possible to control processes in industry, to ensure the necessary environmental conditions for many experiments in science and research and to support the commercial relationship between manufacturers and users of vacuum equipment. The main task of vacuum metrology, the science of vacuum measurement, is to provide traceability of vacuum measurements to the SI. In recent years, also the characterization of vacuum by partial pressure analysis and outgassing rate measurement, and the dynamics of vacuum measurement became an issue for vacuum metrology.     

Gas species, their evolution and segregation through the ITER vacuum systems

This paper takes the ITER fueling requirements and current knowledge of gas balance and exhaust from operating tokamaks to predict all likely gas inputs into the ITER Vacuum systems. Areas where gas dynamics modeling is relevant to the ITER design are highlighted. The design and operation of the ITER vacuum system gives an element of segregation of different gas flows and species. This paper analyses the time dependent gas segregation in the vacuum system resulting from different temperature dependences of cryogenic sorption and condensation processes of different gas species. As a specific example, the optimal transfer of ⁴¹Ar through the vacuum system is studied with respect to its decay and the resulting effects on the design of system components.     

Vacuum heat treatment and brazing of metallic materials

Vacuum heat treatment is applicable to most common metals. Vacuum heat treating processes show a distinct advantage over conventional processes in that vacuum heat treatment obtains a bright surface free of defects such as decarburization and intergranular oxidation. Distortion of the parts normally occuring during conventional processing is minimized in vacuum. Parts may therefore be processed in the fully machined condition. Vacuum furnace brazing renders the use of flux unnecessary; it allows the use of a wide variety of brazing filler metals; improves the physical properties of the joint by eliminating such defects as porosity and oxide inclusions; it enables the successful brazing of the nickel and cobalt base superalloys, a difficult task to achieve by conventional means. A cost comparison between vacuum and conventional heat treating processes indicates that vacuum is the most economical method of processing. The paper intends to relate the above to actual processes and to indicate where considerable savings in labour and time may be obtained by the application of vacuum processing.     

Das Vakuumschulen‐Zertifikat

Certification of Vacuum Trainings This article describes the certification process for quality assurance of vacuum trainings by the German Vacuum Society (DVG). This quality certification was established in 2014. The first certification has been completed, another is ongoing. The certification ensures all participants a certain level of teaching and learning content in both theoretical and practical parts of the trainings. The applicants are assessed by a team of auditors named by the DVG. The procedure also includes discussion about possible improvements. The spectrum of training courses that can be certified covers general vacuum trainings and special training like leak detection, coating technologies, or mass spectrometry. For further information please contact Dr. Michael Wahl, Tel. +49 631 205‐73‐3333, E‐Mail wahl@ifo.uni‐kl.de     

Pirani真空变送器的校准

通过对Pirani真空变送器的测量和校准,分析Pirani真空变送器输出信号和真空度之间的函数关系.由输出信号示值误差与真空度示值相对误差之间的关系,建立Pirani真空变送器的校准装置,并对某类型的Pirani真空变送器进行了测量,测量结果扩展不确定度U=0.046V (k=2),对应于真空度示值相对误差δ不大于±1...     

Kennfeldanalyse einer Schraubenvakuumpumpe

Operating Performance of Screw Vacuum Pumps This paper presents detailed analyses of the operating performance of a dry‐running screw vacuum pump. The characteristic parameters, suction speed and final attainable pressure ‐ which primarily define the operating performance of screw vacuum pumps ‐ are explored in experimental and theoretical investigations. Experiment and simulation in combination are used to show the correlation between the main physical and technical characteristics and the operating performance of screw vacuum pumps. This basic knowledge is essential for understanding the specific machine physics of positive displacement vacuum pumps, especially for screw vacuum pumps, and is useful in view of further design and optimization processes. The experiment covers measurements of the operating performance of the investigated isochoric screw vacuum pump working against ambient pressure. As operating parameters intake pressure (1000mbar to 10^‐3mbar) and rotor speed are varied over a wide range. The theoretical analysis of the operating performance contains simplifying models as well as simulations of the thermodynamic processing. The impact of external leakages, clearance vacuum flows and further losses on operating performance are described in detail.     

空间用油脂材料原位质损测试及出气成分分析方法

QCM（QuartzCrystal Microbalance）作为一种新型的高灵敏度质量传感器,具有测量精度高、稳定性好、体积小和工作温度范围广等优点,被用来监测微小质量的变化。针对QCM的原理,提出了将空间用油脂材料包裹在QCM电极上,在空间材料出气成分分析设备中原位监测材料的质损和出气成分的方法,并对实验方法进行了验证。     

真空开关测试中发现的几个关键质量问题

随着城市建设的发展，需要高压直接送电进入市区的负荷中心，因而要求大量使用占地面积小、安全可靠且无油的高压开关。本文描述了目前在我国中高压配电领域大量使用的真空开关的技术特点，针对真空开关检测中发现的不合格情况，重点介绍在应用和调试真空开关时如何更好地解决真空室漏气、操动机构配合、预防过电压和温升等关键性质量问题。