Geräuscharme Flüssigkeitsring‐ Vakuumpumpen

Besides the requirements for processing, increasing investment charges and working expenses gain more and more importance during the past years as well as the noise level and noise development. Within this work new information's elaborated with regards to noise development were presented for liquid ring vacuum pumps. Based on these test and design data and its interpretation, a new pump type was designed. These studies resulted in a new type range, which corresponds to now‐a‐days standards with regards to increasing requirements on noise development. Combining new knowledge with the up‐to‐now experiences makes us considerably reduce the emissions at source. Latest technologies and production methods enabled us to create a robust construction at a favourable price.     

Die flüssigkeitsfördernde Vakuumpumpe

Within the scope of these works, with regards to the carry of liquid new knowledges as to the processes within the liquid ring vacuum pumps are introduced. Basis of any new development is the comparison of test data of different constructions and its interpretation The new vacuum pump allows — compared to other constructions — within a safe process the carry of fourfold the liquid quantity. For far of the ranges the carry of liquid does not show significant impairments of suction capacity and power input. Despite of fluctuating liquid quantities, these vacuum pumps persuaded in an extensive series of tests at well‐known users under process conditions with regards to their quiet running and constancy of the process parameters.     

Erweiterung der Anwendungsbereiche für Flüssigkeitsringpumpen

New application horizons for liquid ring vacuum pumps – extended capabilities in combinations with side channel blowers After many years of technical evolution and optimisation for specific applications liquid ring technology accepted is now a widely way of generating vacuum. With the launch of closed circuit cooling systems a plug and play solution with integrated water supply is now available. The combination with the highly efficient and compact side channel blower G‐BH8 leads to a considerably extended performance range and remarkable energy savings.     

Vakuumerzeugung durch Produktdampf-betriebene Strahlpumpen in der Kunstfaserindustrie

Vacuum generation by product vapour driven jet pumps in the plastic fibre production For industrial application in the fiber industry product vapour driven jet pumps in combination with liquid ring pumps for generation of vacuum have proved and succeeded. The most important advantages of such vacuum systems are the high operational reliability, small wear and tear, customized design, low environmental impact, reasonable investment costs and simple operation.     

Die Flüssigkeitsring-Vakuumpumpe als verfahrenstechnische Maschine

Liquid ring vacuum pumps have many and diversified applications in the process industry. Primarily they are used to transfer gases and vapours from a lower to a higher pressure level. Due to the specific principles of operation, a heat and mass transfer between the gas or vapour and the sealing liquid takes place also. This can be utilised to perform unit operations. Beside transportation and compression of gases the pump can perform the following operations: exchange of heat, condensation/evaporation, absorption/desorption as well as chemical reactions. Because of these features is the liquid ring vacuum pump a ?process engine”? and an interesting alternative to other process apparatus. Following the definition of H. Brauer (1985) is the objective function of a process engine achieved by a moving element, whereas the objective function of a process apparatus is achieved without any moving element. For nearly all possible combinations of sealant, gases and vapours reliable empirical principles to determine the suction volume and the power requirements of liquid ring vacuum pumps are at hand. Besides has the use of liquid ring vacuum pumps to perform unit operations a long successful tradition. However, the field of applicability can be enlarged if the feasibility of the engine for individual unit Operations can be predicted with the help of physical models. Due to the eccentrically arranged rotor a sickle shaped space is formed between rotor hub and liquid ring where suction, compression and discharge of an gas/vapour mixture can be realised if the suction and discharge slots are arranged in a suitable manner. As the seal liquid is in direct contact with the gases and vapours all reactions inside the pump develop in the direction of a thermodynamical equilibrium between the two phases. An important consequence of this feature is the limit of operation of liquid ring vacuum pumps: the suction pressure has to be above the vapour pressure of the seal liquid. Another consequence is the possibility to utilise this type of pumps for unit operations. The turbulent surface of the liquid ring which is formed by a dense hale of droplets is ideal for heat and mass transfer processes. Following an attempt of C. Pfleiderer, the azimuthale distribution of the static pressure and the contour of the liquid ring can be determined under considerably simplifying assumptions. One of these simplifications is that the condensation and evaporation in the pump is neglected. The further simplifications deal with the significant idealisation of the geometry. Taking back the simplifying assumptions step-by-step and including the thermodynamical circumstances it is possible to calculate the azimuthale distribution of the static pressure and the real contour of the liquid ring for the condensation and the evaporation. These attempts can be carried on to taking several components in the vapour-portion of the gas/vapour mixture into account and form the basis of the calculation of the absorption and desorption. In this case the assumption that the thermodynamical equilibrium is attained instantly is no longer valid.     

Membranvakuumpumpen als Turbo‐Vorpumpen

Diaphragm Vacuum Pumps for Backing Turbo Pumps State‐of‐the‐art turbo pumps with integrated molecular drag stage can be operated with forevacuum levels in the mbar range. Therefore oilfree diaphragm vacuum pumps can be used for backing. Advances of diaphragm technology and electronic drives for speed variable operation make diaphragm pumps even more compact, powerful and reliable. Long term tests running for more than five years indicate a diaphragm lifetime in excess of 40,000 hours and an excellent ultimate vacuum over the full operating time. Especially with variable speed drive systems maintenance intervals similar to turbo molecular pumps are now reachable.     

Flüssigkeitsring-Vakuumpumpen

Liquid ring vacuum pumps – Oldtimers of vacuum technology and yet highly up-to-date Liquid ring vacuum pumps were developed over a hundred years ago. In the meantime, vacuum technology has evolved considerably and offers optimum economic and technical solutions for a wide variety of applications. However, liquid ring vacuum technology still has its reason for existence and is the most suitable principle for vacuum generation in some applications. Thanks to its functionality it is perfectly suited for the extraction of humid gases or vapours. Due to the use of process-compatible operating fluid and the possibility of different construction materials, it can be perfectly matched to different operating fluids and process conditions. In addition, it is available in many sizes on the market and can therefore extract very small and very high quantities of gas and vapour.     

Vakuumverdichterkombinationen aus Flüssigkeitsring- und Drehkolbenverdichter

Reicht das geforderte Vakuum einer Anlage unter den erreichbaren Druck eines Vakuumverdichters hinaus, so werden zwei oder mehrere Vakuumverdichter in Reihe geschaltet, um den geforderten Vakuumdruck zu gewährleisten. Durch Serienschaltung mehrerer Verdichter gelangt man bis in den Hochvakuumbereich mit Drücken von p=0,1 Pa bis 10^?5 Pa oder darüber hinaus in den Bereich des Ultrahochvakuums. Betrachtet man die Bereiche des Grob- und Feinvakuums mit Drücken von p=100 kPa bis 0,1 Pa, also den Druckbereich von sechs Zehnerpotenzen, so wird dieser Vakuumbereich durch Serienschaltung von zwei verschiedenen Vakuumverdichtern folgender Bauarten erreicht: z.B. Hubkolbenverdichter mit Membran- oder Drehschieber- oder Flüssigkeitsringvakuum- oder Vielzellen- oder Drehkolbenverdichter. Im Folgenden wird die bisher wenig beachtete Vakuumverdichterkombination, bestehend aus einem Flüssigkeitsringvakuum- und dem Drehkolbenvakuumverdichter, beschrieben, die insbesondere in der Verfahrenstechnik beim Absaugen von Gasen und Dämpfen große Bedeutung besitzt. Is the pressure in the vacuum system less than the pressure which one vacuum pump can reach, connecting two or more vacuum pumps where in series, will enable reaching the required vacuum pressure. By connecting vacuum pumps in series, it is possible to reach pressure in the high vacuum between p=0,1 Pa to 10^?5 Pa or in the ultrahigh vacuum. For low or medium vacuum with pressures between p=100 kPa to 0,1 Pa, this is a range of six decimal powers, series combinations of the following vacuum pumps types are used e.g.: piston vacuum pumps in combination with diaphragm vacuum pumps or rotary vane vacuum pumps or liquid ring compressors or rotary piston compressor. The following article will describe the vacuum pump combination with an liquid ring compressor and an rotary piston compressor, which has attracted only a little interest up to day. This combination has importance in process engineering for exhaust of gases and vapours.     

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.     

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.     

Multi Inlet Turbomolekularpumpen

Multi Inlet Turbomolecular Pumps for the Latest Generation of Analytical Instruments The analytical market is driven by new challenges from the areas of medicine, pharmacy, environment protection, airport security etc. to develop corresponding detection methods for gases, pyrotechnical products and proteins etc. Without vacuum technology, many physical principles of measurement like e.g. mass spectrometer and electron microscopy, would be unthinkable today. Analytical instruments based on mass spectrometers require a high vacuum to operate. The pressure range is between 10^?3 and 10^?10. Turbomolecular pumps as supplied by the company oerlikon leybold vacuum for the analytical market are suited for generating such low pressures. The latest technology trend is detailed and presented in this article. Innovative solutions are, for example, multi‐inlet turbomolecular pumps with custom housings or cartridge solutions for direct installation within the analytical system.     

Selbsttrocknende Membran‐ Vakuumpumpen für feuchte Gase

Diaphragm vacuum pumps have proved their superiority as dry‐running systems over other types of vacuum pumps in many applications, and in particular in the medical, analysis, and process engineering sectors, as well as in the chemical industry. These pumps deliver the media without any contamination of content, have a high gas tightness, and can be designed as chemically resistant with regard to those parts which come in contact with the media. Although they are in principle relatively insensitive towards condensates which may be formed or conveyed with the media, liquids in the vapor or gas flow may be the cause for the prolongation of a vacuum process, which can be considerable and is certainly undesirable. This applies in particular to applications involving multi‐user vacuum systems in chemical laboratories, which under certain circumstances may contain very substantial volumes of condensates, and to the use of pumps in steam sterilizers (autoclaves) and vacuum drying cabinets. These examples of applications will be considered in greater detail hereinafter. The condensates which occur in the pump head of a diaphragm vacuum pump cause interference in that — due to re‐evaporation during the suction cycle — they incur a substantial reduction in the usable suction capacity of the pump. This problem can be resolved by means of a drying system for diaphragm vac uum pump heads. The drying system makes use in this case of the pressure differential which pertains between the pump chamber and the atmosphere outside the pump. The function of the drying system can be described as follows: A solenoid valve vents the pump head in a cyclic manner, with the result that liquid in the pump head will be blown out, while the process vacuum in the process engineering system will continue to be maintained. Diaphragm vacuum pumps equipped with this drying system have provided excellent results, for example in the chem ical laboratory, both in individual diaphragm vacuum pumps as well as in multi‐user vacuum systems. Extremely good experience has also been gained in the evacuation of sterilizer autoclaves and vacuum drying cabinets with the use of diaphragm vacuum pumps fitted with the drying system. When using the drying system on steam sterilizer autoclaves, another favorable effect is also encountered: The vapor fraction in the pumping medium is cooled in the diaphragm pump head to below the evaporation or boiling temperature, with the result that the vapour condenses. This reduces its volume to a fraction of the initial value, which is the equivalent of an additional suction capacity, in the same manner as with a condenser. The condensate which occurs with this process is blown out of the pump heads by the drying system, and, as a result, can no longer cause interference due to re‐evaporation.     

CXS chemical dry vacuum pump brings smart vacuum to the process industry

The chemical sector as a whole has been quick to recognise the clear advantages of dry vacuum pumps over traditional wet technologies, and dry vacuum pumps are now well established around the world as an efficient, reliable option. A new trend is now emerging: for vacuum to be seen as a ‘utility’. In response, dry vacuum technology is being developed by manufacturers to be available on demand in a ‘plug and pump’ system that requires minimum set‐up and maintenance. The most advanced chemical dry vacuum pumps, such as the new CXS pump from Edwards, deliver exceptional energy efficiency and performance, are cost‐effective to run, and are environmentally sound.     

Vacuum oxygen decarburization (VOD) of stainless steel

High costs for vacuum generation and maintenance can be overcome by replacing steam ejector pumps with mechanical vacuum pumps, initially for the vacuum degassing (VD) process but later also for the vacuum oxygen decarburization (VOD) process. Initial concerns about the technical suitability of mechanical pumps for vacuum processing of large heat weights have proven unfounded. There is no real technical upper limit. With detailed knowledge about the vacuum process mechanical vacuum pumps can be successfully engineered for any heat weight where a steam ejector pump would previously have been selected. In fact, suction speed of mechanical vacuum pumps can be ideally controlled to fit the various phases of vacuum processing. This article will show how mechanical vacuum pumps contribute to significant cost reduction and to the possibility of automation of decarburisation, thereby achieving better process control.     

Membranpumpen mit hoher Kompression durch tangentiale Membraneinspannung

Diaphragm pumps dominate the field of rough vacuum (down to 1 mbar) in modern industry and science. Their construction is quite simple and therefore warrants great reliability. Diaphragm pumps are oil‐free, maintenance free, have a low noise level and a long lifetime. Up to now, problems occurred in generating lower vacuum pressure. With a completely new tangential diaphragm insertion as well as with improvements of the gas flow, and the form and position of the valves, the of a Puchheim pump company now solved this problem: The tangential diaphragm pumps reach an ultimate pressure of 20 mbar (single‐stage) and less than 1 mbar (double‐stage). A pump head provides a pumping speed of 36 l/min at atmospheric pressure.     

New Turbomolecular Pump with Central Opening for Free Axial Access. Eine neue Turbomolekularpumpe mit zentraler Öffnung für freien axialen Zugang

Standard turbomolecular pumps show typically one annular active intake area on the high vacuum flange side (single‐flow pumps). The central circular part of the inlet of the compressor turbine is blind for pumping. The new design proposes a central opening of a turbomolecular pump all along the axis. This central bore can be used e.g. for mounting of feed throughs, manipulators, windows or for coupling to further vacuum devices, in particular also for enclosing tube‐like vacuum systems. This design allows a multi‐use of a pumping port at a vacuum vessel without reducing there the pumping speed. Moreover, the new design is ideal for axial or radial differential pumping arrangements as e.g. needed for all gas jet like set‐ups or other pressure reduction stages.     

Kondensatoren ‐ Ideale Vakuumpumpen ‐ Real berechnet

The accurate design of condensers in the vacuum technology with the help of 'real' flash calculation is possible due to the easy access to calculation programs and databases. The article shows with a simple example, how important the knowledge of the real condensation‐behaviour can be, when designing a modern, effluent reduced vacuum system. In addition, design failures on vacuum condensers can cause trouble in the performance of vacuum pumps.     

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.     

Der Alleskönner der Messtechnik

The all‐rounder of measurement technology – Monitoring of vacuum properties The Novion is an all‐rounder of vacuum measurement technology. The newly developed sensor is based on a novel ion source and an integrated TOF mass spectrometer. The new vacuum measuring instrument is versatile: precise total pressure measurement over a wide range and simultaneously determination of helium partial pressure and residual gas analysis. By using the patented ion source, the instrument also achieves a high dynamic range without the use of a cost‐intensive electron multiplier, down to the UHV range. The Novion comes with a compact design, easy maintenance and an intuitive operation. The article covers the fields of application of this multi‐method sensor and explains its functionality in detail.     

Kompakte trockenlaufende Vakuumpumpen. Compact Dry Vacuum Pumps

Diaphragm vacuum pumps are more and more used e.g. as roughing pumps for wide‐range turbo molecular pumps, gas analysers and other laboratory applications. Recent progress as a result of numerically optimised planar diaphragm technology and electronic drive systems make these systems even more compact, powerful and reliable. Maintenance intervals beyond 40.000 hours of continuous operation – similar to the interval of turbo molecular pumps – seem now reachable with variable speed systems.