“Heat pumps — status and trends” in Asia and the Pacific

In Asian and Pacific regions, economic growth in the last decade has propelled the use of air-conditioners for space cooling along with the use of reversible heat pumps for year round space conditioning. This has led to the rapid increase of electricity demand for air conditioning in summer. To cope with the increasing power demand and the requirement for efficient energy use for space conditioning, governments and energy supply utilities have encouraged effective use and leveling of power load using a heat pump with thermal storage systems and gas cooling systems, by enacting financial and promotional supports. Status and trends of heat pumps in Asian and Pacific regions, related to the use of heat pumps for space heating and cooling were surveyed from the view points of climate, energy consumption, technologies, markets and promotion measures.     

Regional report Europe: “heat pumps — status and trends”

By 1997 about 90 million heat pumps have been installed worldwide, only less than 5% are located in Europe, historically the cradle of this “thermodynamic heating and cooling process”. The majority of the approximately 4 million installed heat pumps are imported reversible air-to-air systems in southern Europe and only 30% represent the typical European-made heating only electric driven compression systems for space and water heating in buildings in central and northern Europe. The first and second oil crises has been the main cause for a first European heat pump “boom” at the end of the seventies. Consequently the following drop in energy prices negatively influenced the market in some countries. The new renaissance in Europe in the middle of the nineties was initiated by the understanding of sustainable development for a more efficient energy use and the related protection of the environment.     

Versuche mit MoS2-Beschichtung zur Verbesserung der Notlaufeigenschaften zwischen Hubring und Flügel der Flügelzellenpumpen bei Verwendung von schwerentflammbaren Druckflüssigkeiten der Gruppe “HFC”

Tests with MoS₂-Coating to Improve the Emergency Operating Characteristics between Cam-Ring and Vanes of the Vane Pumps when Operating with Water Glycol Fluids The relatively poor wear- and corrosion-protection properties of water glycol fluids. Lead to premature wearing of some hydraulic components. In this report we will show, how in the case of vane pumps with a special surface coating improved emergency operating characteristics can be achieved between the moving parts and thereby an increase in the service life of these pump.     

Neue Einsatzmöglichkeiten für Strahlpumpen

Jet pumps are “pumps without moving parts” for the conveying, compressing and mixing of different types of gas, vapour, liquid and solid. For finding new fields of application and for optimising the jet pumps, detailed theoretical and experimental analyses are required. New calculation programs and testing of the pumps on the test bench is the basis for the development of jet 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.     

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.     

Moderne Hochkompressions‐Turbopumpen

Modern high compression turbopumps – Theory and Practice The performance of turbopumps has shown a rapid development since their invention in the middle of the last century. Even though there are limitations due to geometry and general functionality, with the help of clever combinations of standard turbo pumps with Holweck stages, applications nowadays are possible where in the past ion getter pumps were needed. In particular modern high compression turbo pumps are suitable for generating UHV even in combination with small and simple backing pumps.     

Überlastgrenzen bei Hochvakuumpumpen

High-vacuum pumps have a limited inlet pressure above which they cannot function. Recognizing and dealing with the approaching overload conditions is an important aspect of vacuum system operation. This paper outlines the basic considerations for selecting the pressure at which the high vacuum pumps are started, emphasizing the importance of mass flow (throughput) limits rather than the pressure as such. Some basic parameters, such as the ratio of pumping speeds of the roughing pump and the high vacuum pump are associated with the choice of the cross-over pressure. Practical engineering recommendations are offered for system design and operation. Adverse system effects (e.g., backstreaming and oil loss) resulting from pump overload are noted for momentum transfer pumps (diffusion pumps and turbomolecular pumps) and capture pumps (sputter-ion pumps and cryogenic pumps). To prevent any adverse effect, normally, the transient pressure rise during switching should not be longer than a few seconds.     

Abpumpverhalten von Roots‐ und Schraubenvakuumpumpen

Pump down characteristic of Roots pump combinations Combinations of roots pumps and screw type vacuum pumps are often used in industrial vacuum applications because of their high pumping capacity, their compact dimensions and their good energy efficiency. In load lock applications, the type of load control has a high influence on the evacuation time as well as on the energy efficiency of the pump combination. The operation limits of roots pumps are discussed and means to prevent an overload of the pump are introduced.     

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.     

Geräuschberechnungen zur Gestaltung kavitationsarmer Flüssigkeitsringpumpen

A model for calculating the cavitation noise is presented and applied to water ring pumps. The results reveal the influence of hydraulic and constructional parameters. The constants in the semi-empirical equations are derived from experimental data of selected pumps. These equations allow to predict the noise for different operating conditions and geometrically similar pumps. The results provide guidelines for a substantial reduction of cavitation and cavitation-related noise by proper constructional measures.     

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.     

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.     

Heat sources — technology, economy and environment

Heat sources for heat pumps in buildings as well as in industry are discussed. Furthermore, some environmental aspects concerning choice of heat source are highlighted. Only systems for heat pumping are included, i.e. air-conditioning types which can also partly work as heat pumps are excluded. Recent heat pump installations in Sweden are mainly in small systems. Ambient air, exhaust air, soil and rock are the most common heat source types. Data on COP, investment costs, working fluids, present Swedish market etc. for these types of heat sources are given. Data on industrial heat pump installations in some countries and distribution of these according to heat pump type and industry sector as well as heat source temperatures are reported. Process integration aspects when choosing heat source size and temperature are also discussed as well as the relation between these parameters and the choice of heat pump type. Finally, the influence on the economy of the heat source temperature is presented. The cost-effectiveness of heat pumps for reducing CO₂ emissions compared with other heating technologies is discussed. The main results are: (1) heat pumps can in many cases in the future contribute to a reduction of CO₂; (2) there is a rather big difference, for larger systems a major difference, between the water-based and the ambient air-based heat pumps in terms of efficient reduction of greenhouse gas emissions.     

Prüfung von Vakuumpumpen zur Verwendung in explosionsgefährdeten Bereichen nach der Richtlinie 94/9/EG (ATEX 95).

In the following article are described the fundamentals of the EC Type Examinations of vacuum pumps. The essential components of the test are mentioned and explained. Proceeding on the present experiences at the test of vacuum pumps, references for the preparations of EC Type Examinations and for the design of the test samples are given. References for the suitable design of vacuum equipment are mentioned.     

Liquid helium centrifugal pump characteristics from 80 g/s to 1200 g/s

The large amount of data collected from three different centrifugal liquid helium pumps tested, namely with 80, 600 and 1200 g/s nominal mass flow are reviewed. The data include the analysis of the characteristic curves, their total efficiencies, their Net Positive Suction Head (NPSH) and the slip factor. The 1200 g/s pumps tested are of the full emission type, with curved blades, whilst the other pumps have straight blades. The pumps were also tested at different rotary speeds. The pumps were manufactured by Barber & Nichols (Denver, USA).     

“Low-Tech” Innovations

This paper is about an industrial sector which, according to the usual socio-scientific indicators, is referred to as “low-tech”, respectively as non-research intensive and which mostly comprises “traditional” industries. The interest in this sector is motivated by the contradictory situation that, on the one hand, the debate about the perspectives of modern societies focuses on the rapidly growing importance of technological innovations, knowledge and research-intensive economic sectors while, on the other hand, traditional industries make up a considerable fraction of employment and production, especially also in developed economies. On the basis of the results of extensive empirical research, this contribution tries to find answers to the basic question, whether one can speak of an innovation mode typical of the low-tech sector. The institutional based innovation systems approach forms the categorical basis of the analysis. In order to elucidate the specific features of low-tech innovations, they are, in conclusion, compared to the general characteristics of high-tech-based innovation processes.     

Präventivwartung und Wartungsintervalle von Vakuumpumpen

Preventive Maintenance and Service Intervalls for Vacuum Pumps – Avoidance of Equipment Failure and Production Downtime In the day to day private business certain preventive maintenance work e.g. for cars or motorcycles are necessary to maintain the expected mobility in our work and private life. Preventive maintenance and keeping the service intervals for vacuum pumps in all kind of vacuum systems in the work environment are important tasks for the service personel and the system operators. In this article the author wants to provide an overview with recommendations for preventive maintenance and service/overhaul for the most commonly used vacuum pumps.     

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.     

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.