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.     

Wolfgang Gaede ‐ Wegbereiter der Vakuumtechnik

The inventions of Wolfgang Gaede were the beginning of the extensive industrial application of vacuum technology: the 1905 invented high vacuum mercury pump simplified the production of electric bulbs. From this time Gaede joined the company E. Leybold's Nachfolger research & development activities for 40years. Three of his inventions, the diffusion pump, the (turbo‐) molecular pump and the principle of “gas ballast” are worldwide in use even today. The most important stations of Gaede's biography are reported.     

Gaedes rotierende Quecksilberluftpumpe

The rotary mercury pump of Gaede Wolfgang Gaedes invention of a quickly acting high vacuum pump was induced by his studies about the Volta effect. The so far known pumps were not able to create sufficient low pressure to optain very clean surfaces. Alfred Schmidt, owner of the E. Leybold’s Nachfolger Company, Cologne, learned from the publication about the demonstration of the pump its importance. He made an agreement with Gaede to develop together the invention during 1906 and 1908 to a product for use in industrial application – first step into industrial high vacuum technology     

Der Gasballast

Wolfgang Gaedes last important invention: the Gasballast Gaedes invention of the rotating Mercury‐vacuumpump made highvacuum technology available for the industrial production. A second and third impact was given by gaedes molecular‐ and diffusionpump respectively, both depending on physikal effects firstly used for vacuum generation. Vacuum technology becomes increasing importance but the common oil sealed rotating pumps for fine vacuum suffer from contamination of the oil by vapor condensation. It was another invention from Gaede that eliminated this handycap in a very elegant way: the gasballast that is up to now a very important feature of this type of pumps.     

Engineering aspects of turbomolecular pump design

The development of modern (thin-bladed) turbomolecular high-vacuum pumps began in 1957 with the demonstration of the possibility of obtaining high compression ratios with axial flow compressors in the molecular flow regime. Thirty years later, such pumps had become the major method for high vacuum pumping. It had been apparent from the beginning that pneumatic compressors can be useful at any pressure provided a proper number of suitable impellers were used. However, theoretical studies, initially by Prof. A. Shapiro's group at MIT (Massachusetts Institute of Technology) dealt primarily with the pumping mechanism in molecular flow rather than with an optimum practical pump design. Some observations in such studies were misunderstood and the first pump designs were not optimized. Later, compound or hybrid pumps were introduced, which incorporated molecular drag pumping stages. In more recent years, pumps have been made which can exhaust directly to the atmosphere by means of added centrifugal-regenerative impellers. The use of different impeller types provides freedom to the designer to create pumps that match any reasonable desired performance.This paper will attempt to explore some of the engineering aspects of design, especially relationships of volume and mass flows, permissible pressure ratios in various density domains, and their relevance to power consumption.     

无油分子泵机组的组装

介绍了将ALCATEL公司生产的一台ATPl00涡轮分子泵、一台MDP50ll牵引分子泵及一台VRC公司生产的lBy6型干泵组装成无油分子泵机组的过程。文中给出了泵间配合的计算、机组方案的设计、连接管路、仪器支架的设计及选择。本机组所采取的设计方案使三个泵都最大限度地发挥了优点避免了缺陷，较好地满足了使用要求，为今后选购单泵和组装无油分子泵机组提供了可靠的理论和实验依据。     

100 Jahre HV‐Pumpe von Wolfgang Gaede. 100th Anniversary of Gaede's High Vacuum Pump

In 1905 Wolfgang Gaede invented a sturdy, quickly operating high vacuum pump, which was easy to use. It was produced and distributed under licence from E. LEYBOLD’s Nachf. This firstly allowed the application of high vacuum technique to industriel production. Gaede continued to work with Leybold just to the end of his life in 1945.     

Design and performance characteristics of sorption pumps

This paper describes the design and performance characteristics of two types of refrigerated Molecular Sieve Sorption pump that produces and maintains a pressure of the order of 10⁻³ torr in volume of 10–50 l. in case of evacuation of air from atmospheric pressure. The main feature of this method of pumping is its freedom from pumping fluids. Some of its applications along with its limitations are discussed. Applications to multistage sorption pumping and the use of sorption pumps in combination with mechanical dry pump are illustrated.     

Probable cause analysis of cracks observed on vertical centrifugal pump

Two identical vertical centrifugal pumps are used to cool the equipment used for electricity generation by combined cycle. One of these two pumps is cracked at its elbow, unlike the second which operates under the same conditions and which displays no anomaly. These cracks whose causes remain undetermined present a serious threat to electricity production. These causes may be of a mechanical nature related to the nature of material of the pump or related to the dynamic flow characteristics. The first hypothesis was excluded since both pumps are made from the same material (ductile iron (S-NC 20-2)), which leads us to analyze the second hypothesis by studying the flow occurring in the pump for particular operating conditions. Two scenarios are considered in this work, the first considering an improper attachment of the wheel upon its replacement, while the second deals with the possibility of a sudden closing of the valve “water hammer”. We therefore propose in this work, the numerical modeling of the flow through the vertical centrifugal pump. The study was conducted using the computational code Fluent. The studied pump provides a flow of 18,100 m³/h with a total head of 10.1 m head. Fluent simulation of the pump operation for the two selected scenarios and the comparison between the results obtained and those of the normal operation allowed us to conclude that a sudden closing of the valve is the most likely cause explaining these cracks on the one of two pumps.     

Geschichte der Vakuumtechnik. History of Vacuum Technology

The history of vacuum technology is more than 2000 years old. Over the past 400 years scientists, engineers and inventors such as Torricelli, Pascal, von Guericke and Gaede have been engaged in vacuum technology. Vacuum has become an essential instrument in science and technology and many processes could not exist without it. Furthermore vacuum technology has been developed as an individual industrially applied technology. The article describes the development of vacuum technology from ancient philosophical speculations about the mercurial glass pipe to the modern diffusion pump.     

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.     

Völlig ölfreie neue Vorvakuumpumpe für saubere Anwendungen

Totally oil-free vacuum pumps have been gaining popularity for applications where clean forevacuum is needed, or clean gases are being pumped. The trend for these simple applications has been to substitute the complicated and expensive process pumps used in the production of semiconductors with simpler alternatives. In order to produce such a cost effective oil-free vacuum pump, the well known reliable and robust piston principle has been adapted as a vacuum pump. The resulting product is made up of four stages of compression arranged in series producing an ultimate pressure of 3 ? 4 × 10^?2 mbar. All compression spaces are totally dry as is the crank case. For additional cleanliness the grease lubricated bearings situated in the crank case are separately sealed. The special valve geometry, and the use of new low coefficient of friction sliding materials, combine to produce a very robust and low maintenance pump. The new pump is capable of surviving operational accidents such as the ingestion of broken wafers or liquid water. Applications for this new pump include load locks, analytical instruments, and research.     

高效液相色谱输液泵流量脉动的研究

设计并搭建了输液泵输出流量脉动测试装置,在不同测试条件下,研究了高效液相色谱系统中常用的串联式和并联式往复柱塞泵的流量脉动。实验得到了这2种输液泵流量脉动率随流量或背压的变化趋势,并证实输液泵的流量脉动周期与凸轮运动周期接近。利用脉动阻尼器来降低流量脉动,可使2种输液泵在6.5 MPa背压下的流量脉动率降为原来的10%左右。该测试装置及方法可在高效液相色谱输液泵的设计改进过程中提供帮助。     

A Simplified Model to Estimate the Size Distribution Change of Polydispersed Aerosol for Cyclone Separator

ABSTRACT

Although the air-lift pump has been superseded by submersible pumps in raising water from wells and mines, it still provides an attractive means of lifting abrasive slurries because, unlike mechanical pumps, it has no moving parts to wear. However, current design of air-lift pumps must rely on empirical equations, or, at best, incremental computer solutions. Design is complicated by the fact that relative velocities of the phases change over the whole pump length. A new design equation is developed to predict the lift of an air-lift pump, given the flowrates of air, liquid and solid in the pump, and the dimensions of the air-lift tube. The new equation is baaed on well-established multiphase flow theory, and offers significant advantages over current design techniques. In combination with an equation for the overall pump efficiency, the new equation provides a method for optimizing the design parameters for the air-lift pump.     

Optimized annular triode ion pump for experimental areas in the LHC

The large hadron collider will be the world next generation accelerator to be operational in 2007 at CERN. The UHV requirements force the installation of ion pumps in the experimental areas of ATLAS. Due to the unacceptable particle background that standards ion pumps may generate, a reduction in the amount of material constitutive of the pump body is required. Hence, a stainless steel 0.8 mm thick body annular triode ion pump has been designed. A pumping speed of ∼20 l/s at 10⁻⁹ mbar is provided by 15 pumping elements. Finite elements analysis and destructive tests have been performed in its design. Final vacuum tests results are shown.     

叶片泵振动机理特性分析及改进设计

机械设备振动和设备组成、工作机理、工作状态等息息相关,船用常见设备如水泵、风机等由于工作机理各不相同,其振动频率特性也各不相同。通过对旋转类设备振动特征进行对比分析,分析设备主要振源及其成因,提出设备改进方向,并进行针对性改进设计,试验结果表明,取得了良好的效果。     

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.     

Operation and Improvement of Liquid Nitrogen Pumps with Radial High- Temperature Superconductor Bearings

This paper reviews the advantages of replacing the mechanical bearings of low-temperature pumps by radial high- temperature superconductor (HTS) bearings. Radial HTS bearings have the advantage of being non-abrasive, so that the working life is increased significantly. In this article, two types of liquid nitrogen pump with radial HTS bearings are proposed. To reduce heat leakage, one pump uses a permanent magnet (PM) coupling and the other uses a long hollow pipe coupling. Successful stable operation of these two pumps means that radial HTS bearings have the potential to be applied in liquid nitrogen pumps. Test results show that the flow rate is influenced mainly by rotational speed but not by the coupling component. Further designs of the two types of pump for practical applications are described, and their characteristics are analyzed: the pump with a PM coupling has lower heat leakage, whereas the pump with a long hollow pipe coupling can solve the force creep problem of the HTS bearing. The design of the pump with a long hollow pipe coupling is based on the pump that is already in practical use, and therefore has greater feasibility for practical applications. Finally, improvements of the liquid nitrogen pump by improving the structure of the pump and the performance of the radial HTS bearing are discussed.     

Supercavitating pumps for cryogenic liquids

Pumps for cryogenic liquids have a number of special mechanical and insulation problems because of the low temperatures. In addition there can be hydrodynamic problems due to trying to pump the liquid near its boiling point c causing cavitation. The problems of cavitation in pumping are discussed and the limitation and effects that this imposes on the pumps. The supercavitating pump enables many of these problems to be overcome and allows the pump to be operated at inlet pressures of one third of that of conventional pumps, which has clear advantages in the cryogenic field. The characteristics are given of some prototype supercavitating pumps that have been running for over two years.     

HYDRAULIC TRANSPORT OF ABRASIVE SOLIDS: THE AIR-LIFT PUMP

Although the air-lift pump has been superseded by submersible pumps in raising water from wells and mines, it still provides an attractive means of lifting abrasive slurries because, unlike mechanical pumps, it has no moving parts to wear. However, current design of air-lift pumps must rely on empirical equations, or, at best, incremental computer solutions. Design is complicated by the fact that relative velocities of the phases change over the whole pump length. A new design equation is developed to predict the lift of an air-lift pump, given the flowrates of air, liquid and solid in the pump, and the dimensions of the air-lift tube. The new equation is baaed on well-established multiphase flow theory, and offers significant advantages over current design techniques. In combination with an equation for the overall pump efficiency, the new equation provides a method for optimizing the design parameters for the air-lift pump.