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.     

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.     

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.     

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.     

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.     

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.     

Tribologische Sub‐Mikrometer Schichten für Mikrosysteme

With increasing interest in microelectromechanical systems (MEMS) a high demand on performance and lifetime arises. One option to improve this reliability is the optimization of friction and wear behaviour. Therefore we present a selection of well established systems that were scaled to serve as microtribological coatings. Hard and superhard coatings like DLC, CN_x, cBN and Alumina were investigated and optimized. For a better understanding of the tribological processes and the occuring effects in microsystems we used the macroscopic pin on disc test as well as nanoscale characterization like AFM based nanoindentation and a newly developed tape abrasive wear test.     

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.     

PVD‐Nanocomposite‐Beschichtungen für die Zerspanungs‐ und Umformtechnik

PVD Nanocomposite coatings for the machine cutting and deformation technique Physically and chemically separated wear‐protection layers exhibit increasingly more complex structures. Similarly to the a coil of compact materials increase also here solutions develop as composite materials, which are offered in the form of Nanocomposites. An industrially available solution represents the system MeN/Si₃N₄. This is to be introduced concerning its characteristics as well as its application type within the range of the machine cutting and deformation technique.     

Hydroform‐Technologie für hoch belastbare Stab‐Knoten‐Bauweisen

Hydroforming Technology for Highly Loaded Truss Structures Truss constructions are often prefered because they can be built up highly variably starting with simple elements. In the present study light weight structures for heavy loads handling systems are considered. The hydroforming technology offers the possibility to manufacture highly precise stress adaptive tubes and nodes for such structures. The tubes and nodes are manufactured from thin walled tubes. However, the expenses for hydroformed parts are quite high. In the present paper possibilities are outlined to decrease these expenses significantly by reducing the number of different elements that are needed for the constructions down to a minimum, furtheron, by a careful optimization of the structures and their elements, and by the utilization of variable hydroforming tools. Of primary importance, however, is that the hydroformed structural elements can be highly loaded, that they safely operate during their service life and that they are resistant against environmental influences. For the realization of hydroform parts and tools an integrated design concept is proposed. The influence of hydroforming on microstructure is also considered.     

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.     

Prüflecks für Schnüffel‐Lecksucher

In the testing of leak tightness and in the localisation of leaks by means of a test gas, proper operation and sensitivity of the employed instrument must be checked by a certified reference leak. In the so‐called sniffer mode of operation, the component under test is filled to overpressure with the test gas, so that in case of a leak there is a gas flow from the component to atmosphere. The atmospheric gas is sucked by the instrument and probed for its test gas content. For checking the instruments performance, commercial test leaks are available for various gas species, which deliver a well‐defined leakage. Construction and properties of such a test leak are described. The leak has an internal gas reservoir and a capillary as leak element. Because the inlet pressure at the capillary is kept constant by a pressure controller, the leakage remains constant over several years despite the gradual pressure decrease in the gas reservoir. The calibration of the leakage via the volume flow rate is described in detail. The volume flow rate can be measured by a liquid drop in a measuring capillary as well as a displacement piston in a dosing syringe.     

PVD‐Metallisierung von Polymerfolien für elektronische Anwendungen

The steady growing miniaturisation in the interconnection technique make the use of new techniques for structuring and basic materials for the steady growing mass market necessary. The new generation of flex materials affords high reliability in respect to the FPC rules to make product innovations in a big market possible. Especially the long time stable adhesion which is important for the use of the flexible materials in a large application field is object for further efforts of developments.