Membrantechnologien für Vakuumpumpen

Diaphragm Technologies for Vacuum Pumps Diaphragm vacuum pumps are used in chemistry and as roughing pumps for high vacuum systems. Both planar diaphragms and moulded (also as »structured«) diaphragms are common. Long term tests confirmed that after some hundred hours of operation the ultimate vacuum of pumps with moulded diaphragms deteriorates due to fatigue and abrasion of the elastomer. In addition the pumping speed curve of moulded diaphragms is unfavourable for practical applications. Planar diaphragm pumps show a superior pumping speed curve and — depending on manufacturing quality — a stable performance over the whole lifetime in excess of 10,000 hours.     

Vakuumpumpen für das Chemielabor

The choice of a vacuum pump for the chemical laboratory depends more and more on economical and ecological qualifications. The water jet pump, widespread because of its simple and robust design, can satisfactorily fulfil these qualifications only in a few applications. Rotary vane and diaphragm vacuum pumps are of much more complicated design; the most outstanding assets, however, are that they work without contamination of water; further, they provide a large pumping speed also at low suction pressures.     

Kommunikationsoberfläche Membran‐ Vorbild für moderne Nanoanalytik

A central event in the life of a cellular system is the interaction between the exterior and the interior compartments. Biochemical signals arrive at the cellular surface, bind to their membrane bound receptor followed by a conformational change triggering the release of an internal chemical or electrical signal.This basic principle is followed by all our perceptive abilities like sense of smell or taste, but also by different signal transduction pathways involved in nerve conductivity, vision, sense of touch or hearing. To follow and mimic this principle of parallel registration is one of the aims of modern nanobiotechnology. If we are able to specifically biofunctionalize small arrays of a solid surface, which could be an electrode or a semiconductor, this approach will enable us to build up devices called “biochips” or “biosensors” that allow the determination of bioactive molecules with high specificity at lowest concentrations. Potential pharmacological active substrates might be screened as well as new receptors may be determined. Applications in genomics as well as proteomics are realistic. The major prerequisite for such a broad spectrum of applications is the fabrication of receptive surfaces. Biomolecules have to be surface‐adsorbed in a highly reproducible, oriented and well organised fashion, a task which in biology is taken by the cellular membranes as external or internal receptive surfaces. The physical principles like hydrogen bonds, electrostatic or hydrophobic interactions that lead to such an organized surface are well known. To synthesize molecular building blocks and to position them onto an otherwise unspecific surface is one of the challenges of nanobiotechnology combining biological knowledge and chemical skills with biophysical techniques that allow to handle or analyze even single molecules.     

Betriebsmittel für mechanische Vakuumpumpen in der chemischen und der verwandten Industrie

All vacuumpummps which use a liquid as a sealing-agent have to take care of their specific demands. In this paper liquid-ring-vacuum-pumps will be short mentioned, because the user is familiar with this pumps and alternative fluids. Using other fluids in other mecanical vacuumpumps are not in operation in the field of the various applications frequently. You will find some ideas for using other fluids which are possibly used in rotary-vane vacuum-pumps to find more consideration in the future.     

Explosionsgeschützte Membran‐Vakuumpumpen nach Richtlinie 94/9/EG (ATEX 100a)

For equipment of a mechanical nature which is intended for use in areas subject to the risk of explosion, Directive 94/9/EC (often referred to as ATEX 100a) and its implementation in national law establishes for the first time binding safety requirements in the form of protection targets to be achieved. To fulfil these targets, pump manufacturers are obliged to determine the necessary safety measures for their products in a specific manner, and implement them accordingly. Taking as a basis a gas delivery pump for the chemical industry and environmental engineering, the article describes a number of important sources of ignition which are to be avoided with regard to the mechanical part. It also describes the means by which this can be achieved. One key topic is the drive motor of the gas delivery pump and the certification of its manufacture according to directive 94/9/EC. If the requirements of a particular application with regard to explosion protection are too special for them to be fulfilled with a standard pump, the pump manufacturer carries out customer‐specific projects. The author provides an example to give an insight into the performance of such projects.     

Sicherheitnorm DIN EN 1012 – 2 für Vakuumpumpen und VBG 16

The European Standard EN 1012 – 2 Compressors and vacuum pumps – safety requirements is established in March 1996. The English text will be published in 1997. This standard is deduced from the ?Mashinery directive”? which has the state of a law in all EC member states and superseeds all so far existing national standards on this subject. In Germany for vacuum pumps it is the ?Unfallverhütungsvorschrift für Verdichter”? (compressors and vacuum pumps) VBG 16, which now is partially replaced by the new standard EN 1012. In the following the contents and the mode of employment of the new standard is discussed.     

Aufbau und Eigenschaften verschiedener ölfreier Vakuumpumpen für den Grob- und Feinvakuumbereich

The development of high vacuum pumps and systems during the last 35 years can be characterized by a trend of gradual elimination of liquids exposed to vacuum environment. The need for high purity vacuum process equipment precipitated the development of new pumping techniques: iongettering pumps, turbomolecular pumps and cryopumps. During the last 5 years, a number of dry coarse-vacuum pumps have been developed. Some are entirely oilfree, some still use lubricants at the seals separating the driving mechanism from the vacuum side. This review contains general design and performance characteristics of four classes of equipment: hermetically sealed pumps using bellows to isolate the driving mechanism, a variety of multistaged positive displacement blowers, pumping trains based on turbo-drag pumps, and multistaged reciprocal piston pumps. It is entirely practical to achieve pressure of 10⁵ to 10⁶ while discharging to atmosphere. Despite a complete absence of conventional lubrication in some of these pumps, periods exceeding 10000 hours without maintenance are obtained, providing a viable technology for clean vacuum systems.     

Mechatronische Lösungen für trockenlaufende Vakuumpumpen. Mechatronic solutions for dry vacuum pumps

Mechatronik is a combination from Mechanics and electronic and can be defined as a special view and method of engineering. The main difference compared with the traditional way of mechanical and electronic design is the other way of specification and engineering. Interfaces and specification are focused on different blocks and modules on a functional way, independent how it is realized. The results are not only new innovative solutions with better usage of the modern control possibilities. Also for the interfacing, installation and support this way of engineering give many advantages and possibilities for cost reduction. This paper shows on dry vacuum pumps and systems in the chemical and pharmaceutical industry the actual solutions which are available to use these advantages.     

Entwicklungstendenzen von Vakuumpumpen für die Grob‐ und Feinvakuumtechnik. Developing trends of vacuum pumps for the roughly and fine vacuum technology

Presently coarse vacuum and fine vacuum is generated in engineering arrangements mainly with rotating displacement compressor pumps and some special current machines as well as by means of combinations of these pumps. Besides, took place in last decades a noteworthy change of the used styles of vacuum pumps and her parameters which is not concluded up to the today's day. She will also continue in future with the advancement of vacuum pumps and with the new development of machines and investment‐engineering requirements. In the following contribution some promising developing trends are outlined, outgoing by the today's developing state of the mostly used vacuum pumps, for the closer future. This is sensible because in last decades important ranges of application as for example the food industry or the microelectronic one and the pharmaceutical industry came.     

p‐TCOs für Transparente Elektronik

p‐type TCOs for use in transparent electronics In this article, a new type of semiconducting material is introduced. Transparent conducting thin films are already established in our everydaylife. But the type of these so‐called ?TCOs”? is dominated by electron transport, that means they are n‐type. To get transparent p‐n‐junctions and therefore transparent electronics, the missing part is a transparent p‐type material. Researchers all over the world have found different approach to produce this new generation of materials. At the Fraunhofer Institute for Surface Engineering and Thin Films (IST) in Braunschweig it is now possible to produce these kind of thin films as well.     

Kohlenstoffbasierte Beschichtungen für automotive‐Komponenten

Carbon‐based coatings for automotive components The outstanding properties of carbon‐based coatings are the low friction against steel and the wear resistance, interconnected with the high hardness. In lubricated systems coatings only work in the mixed and boundary friction regime; this means as long as primary body and counter body are still in contact. The properties of coatings can be adjusted in wide ranges. A purposeful adaptation requires that the tribological system is sufficiently well understood. It has been shown that solutions based on coatings are only sub‐optimal if the coating is only introduced at the end of the designphase. A greater benefit is obtained, when the scope for development as given by a coating is utilized already in the early design phase. The coating is accepted as a design element. To test the suitability of the selected coating quickly and inexpensively in advance, the usual standard laboratory tests are not always appropriate. A test set‐up has to be close enough to the application to generate useful results. These considerations are illustrated using the example of a piston pin coating. The roughness of the primary body and of the counter body is of particular importance for the adjustment of the coating system, when high loads are applied. The example presented here shows that the usual indicators for surface roughness like R_a and R_z are not always sufficient.     

Kollektorbeschichtungen für die EUV‐Lithografie

Collector Coatings for EUV Lithography Extreme ultraviolet lithography (EUVL) is the next generation lithogra phy method operating at the wavelength of 13.5 nm (14 times shorter than current lithography systems), enabling semiconductor scaling to resolutions of 22 nm and below [1]. This paper presents the successful coating of the world's largest ellipsoidal collector mirror for EUV radiation with a diameter of 660 mm ( Fig. 1 ). In order to achieve the required peak reflectivity of more than 65 %, the ellipsoidal collector was coated with a highly reflective, laterally graded multilayer using the dc magnetron sputtering system “NESSY”. A maximum reflectivity of the laterally graded multilayer of more than 65 % was achieved for radii smaller than 220 mm. For radii between 230 mm and 320 mm the reflectivity decreases to a minimum of 58 %. The targeted wavelength remains constant at (13.50 ± 0.05) nm over the entire collector surface which is well within the tight specifications for high volume manufacturing.     

Ventillose Flüssigkeitsring‐Vakuumpumpen

Valveless liquidring‐vacuumpumps Besides the procedural requirements in recent years, investment‐ and operation costs become more and more important. In the context of this essay concerning the simplification of the construction and reduction of the costs of wear the latest technical expertises to the processes in liquid ring vacuum pumps have been presented. The analysis of present single stage liquid ring vacuum pumps with valve technology over the whole pressure range was source for a new development. Result of the examinations is now a product range, which sets new standards concerning the more and more important cost consciousness. The combination of latest perceptions with existing experiences lead to a considerable simplification of the construction and an improvement of the operating behaviour. Latest technologies and possibilities of production made possible a robust and low‐cost construction.     

Entwicklung und Herstellung eines neuartigen,bauartzugelassenen Tankcontainers für Bortrifluorid und andere hochverdichtete Gase

Development and construction of a new type, design-approved tank container for boron-tri-fluoride and other highly compressed gases A new type of tank container was developed and tested during a period of about two years and approved by the Bundesanstalt für Materialprüfung (BAM) for transporting boron-tri-fluoride and nitrogen. The total weight of this tank container is about 1500 kg and its capacity about 450 litres. This tank container - in comparison to single pressure gas bottles - allows the transport of larger quantities and shall replace gas bottles or bottle batteries in a safe way or shall be used as a supplement to them. Since the container is mounted on a supporting structure, it can be moved by fork lifters, fork-lift trucks or cranes. The transport can be made by truck, rail or ship.     

Plasmaprozesse für 3D‐Formteile

Plasma treatment and coating processes for 3D parts Many articles of our daily use are only able to feature their outstanding performance due to innovative plasma surface treatments. Semiconductor components like flat panel displays, solar panels, DVD / Blu‐ray Discs, as well as optical components, coated glass panes, cutting tools and other components with reduced wearing are just a few examples. One important quality feature is to reach uniform properties over the entire surface to be treated. In case of planar or slightly curved surfaces this can be relatively easily achieved by using common plasma sources. For complex 3D parts, the effort required for uniform surface treatments greatly increases, and complex movements of the 3D parts are often required to achieve uniformity. This article deals with the plasma surface treatment and plasma coating of such complex 3D parts referring to some selected examples.     

PM‐Werkstoffe für warmgehende Werkzeuge

PM‐Materials for Hot Working Tools Tools and wear parts for compacting tools are subjected to high abrasive wear and mechanical loading at elevated temperatures. MMC's based in iron‐ or nickel with hard particles are developed and investigated. The materials were manufactured from powders by hot isostatic pressing (HIP) and subsequently heat treated. Diffusion between hard phases and metal matrix brings about certain micro structures which were tested with respect to the resistance against sliding abrasion at room and elevated temperatures. Three‐point bending tests and thermal cycling of the material was utilized to characterised the mechanical behaviour. Based on this results a toolkit for a roller press for briquetting was produced and brought into application.     

Anforderungen an Metalloxid‐Schichten für Interferenzoptik

Metal Oxide Films for Interference Optics: Demands on Quality – State of the Art in Production Demands on quality and stability of PVd‐metal oxide coatings are increasing with modern optical systems, complex structures and extension to short and long waves. Deposition requires always, independent on starting material, reactive technologies. Basic PVd‐processes are either fast running but low in particle energy (evaporation), or exactly the other way round (sputtering) or have disturbing side effects (arc ablation). It is shown how they are modified and improved to become effective in reliable and fast deposition of high quality, low defect films. This is performed by adding ions and plasma species or combining magnetic fields and operate the various hybrid processes in continuous or pulsed modes. Characteristic data of the processes are presented as well as properties of metal oxide films produced with energetic reactive, continuous and pulsed plasma processes.