Anforderungen an Vakuumpumpen zur Verwendung in explosionsgefährdeten Bereichen

The Directive 94/9/EC describes the conception and structure of equipments and protection systems for use in potential explosive atmospheres on the European Market. It becams legal validity the 1^st July 2003. For help the manufactures to fulfill the requirements, the following paper want to give informations to the manufactures and also to the operator of explosion protected vacuum pumps to the application of the existing legal and, partly, to the normative regulations, which are still under evaluation. There are shown the legal and normative regulations as well as the essential requirements for ensuring the explotion protection for vacuum pumps. Possibilities to avoid ignition sources at operations in, and the discharge of potential explosive atmospheres are also given.     

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.     

Neue Möglichkeiten zur Grobvakuummessung in explosionsgefährdeten Bereichen

Absolut pressure gauges with fully electronic signal processing designed according to explosion protection tech nique »Intrinsic Safety« for use at hazardous locations offer many advantages at reduced cost. Capacitive pressure transducers with aluminium oxide diaphragm guarantee an optimum of corrosion resistance (especially important for chemistry applications). The absolute pressure is measured with high accuracy. Temperature‐ and long‐term drifts are minimized. The gauges do not have damageable moving parts and are insensitive to vibrations and pressure shocks. An integrated current loop interface allows automatic switch‐on and read‐out of the gauges.     

Druckversuch an Scheiben zur Prüfung der Wasserstoffversprödung von Metallen

Disc-Pressure-Testing of Hydrogen Embrittlement An apparatus for disc-pressure-tests is presented. The bursting pressure with helium and with hydrogen is measured versus the rate of pressure increase. Under hydrogen most metals show a distinct minimum of bursting pressure. Some explanations for this minimum are proposed. The maximum ratio of bursting pressures x = (P_He/H_H2)_max is taken as an indicator for hydrogen embrittlement. Steel similar to SAE 4137 (34 CrMo 4) is tested in several states (tempered, normalized, cold-rolled), as well as austenitic steel, various other metals (V, Nb, Ta, Mo) and some amorphous metals. The disc-pressure-test is shown to be easy and useful for determining hydrogen embrittlement. Even austenitic steel exhibits some embrittlement (x = 1.5). The strongest embrittlement occurred in amorphous metal Vitrovac 0040 with x = 9.8.     

Die Zerstörungsfreie Prüfung der Hubbänder der OTTO-HAHN-Brennelement-Wechselmaschine nach einem speziellen Ultraschallverfahren

The Guarantee of Quality for the Steel Hoops of the Refueling Machine of the Nuclear Ship OTTO HAHN by Way of a Special Procedure with Ultrasonic The basic overhaul and renewal of the refueling machine constructed 1965–1967 for the reactor system of the nuclear ship OTTO HAHN required among other things the replacement of the lifting hoops which are necessary for raising the fuel elements and guiding the gripping device. These steel hoops are the critical components of the refueling machine. Therefore the quality assurance of the material was articularly specified. On way of ensuring this guarantee of quality is to carry out tests involving the use of ultrasonic equipment as desired and applied here. The process is explained and its application with the results obtained is described.     

Der Beitrag der zerstörungsfreien Prüfung zur Zuverlässigkeit und Verfügbarkeit korrosionsgefährdeter Komponenten von Chemieanlagen

The part of Nondestructive Testing of Ensure Reliability and Availability of Components of the Chemical Process Industry under Corrosive Conditions Corrosion and wear failures very often are initialized or at a minimum influenced by faults in design, manufacturing and installation. If we reduce these faults, the result will be an increasing working life of the components. To solve this problem, we recommend the consequent use of NDT-techniques.     

Methoden zur mechanischen Charakterisierung von modifizierten Implantatoberflächen in der Orthopädischen Chirurgie

Methods for the mechanical characterisation of modified implant surfaces in orthopaedic surgery Nowadays, on average approximately 10 % of all hip and knee endoprostheses have to be exchanged within the first 10 years. Implant revision is often necessary following aseptic or septic loosening. Hence, today implants for orthopaedic surgery are increasingly being coated for better osseointegration. Coatings have to be biocompatible and meet high mechanical requirements, whereby the adhesive strength and the abrasive wear resistance of the coatings take on a key role. This study presents different methods to asses these parameters experimentally using two innovative coatings (TiN, TiO2‐Cu) exemplary. The adhesive bonding strength of the coatings was investigated using different standardised methods, such as the arbour bending test, scratch test and the standard adhesive test. Wear resistance was determined after 1.5 million cycles in a special testing machine. The investigations showed for both coatings, TiN and TiO2‐Cu, good adhesive strength and wear resistance. The adhesive strength and wear resistance of bio‐active, wear reducing or anti‐allergenic surface coatings can be determined reliably using the above‐mentioned methods.     

Meßwertstreuung in Abhängigkeit von der Werkstoffhärte bei Kleinlasthärteprüfungen nach Vickers und Knoop

Dispersion of Vickers and Knoop diagonals as a function of workpiece-hardness at low load testing . A statistical analysis of low load hardness test results measured under industrial conditions by the comparative use of Vickers and Knoop indenters was carried out. Accordingly, recommendations can be given for the number of indentations necessary to ensure a constant shape of the distribution of sample means all over the investigated hardness area from approx. 150 up to 950 daN/mm₂.     

Diffusionsvorgänge in der Kontaktzone von Titan/Stahl-Sprengplattierungen

Diffusion in the contact zone of explosion-welded titanium-clad steel plates. After diffusion heat treatment, the intermetallic compounds Fe₂Ti and FeTi were found to exist in the contact zone of titanium — Clad steel plates. The bond strength of these clad plates may possibly be impaired by the segregation of titanium carbide in the FeTi layer. In addition, cavities form adjacent to the intermetallic phases in the titanium after prolonged heat treatment. Titanium concentration in the fusion zones was found to be 55 ± 2 w/o (balance iron). After heat treatment of this specimen, FeTi was found to be predominant.     

Einsatz physikalischer Analysemethoden zur Charakterisierung von dünnen Schichten und Grenzflächen in der Halbleiterindustrie

Characterization of thin films and interfaces are necessary in semiconductor industry to ensure high yields and the required reliability of the products. Requirements to thin film and interface analysis are reviewed, and typical applications in semiconductor industry are shown. Thin film characteristics which have to be determined using physical analysis techniques are film geometry, surface and interface roughness, chemical composition, and microstructure. Advances in physical failure analysis are essential to the reduction of feature size and introduction of advanced materials and processes for future technology generations. Future trends are discussed. To reduce the time for problem solving in the manufacturing process, out of‐fab characterization tools will partly move to“at‐line” labs which are located next to or sometimes inside the cleanroom.     

Oberflächenspezifische Analysenverfahren (AES/SAM,ESCA/XPS,SIMS) und ihr Einsatz zur Untersuchung von Verschleiß-Schutzschichten

Surface-Specific Analytical Methods (AES/SAM, ESCA/XPS, SIMS) for the Investigation of Wear-Resistant Coatings This paper gives a brief review of the analytical possibilities by combining some analytical methods of surface analysis for the study of the uppermost layers of atoms of technical interesting materials (metals). The physical fundamentals, limitations and differences of the methods: Auger electron spectroscopy, X-ray photoelectron spectroscopy and secondary ion mass spectrometry are discussed – especially in comparison with the well-known electron microprobe analysis. Finally the application of surface analysis for the characterization of the chemical surface composition of wear-resistant coatings before and after tribological operation is demonstrated.     

Reliability of masonry walls subjected to in‐plane loading: A slip failure along head joints / Zuverlässigkeit von Mauerwerkswänden bei Belastung in der Ebene: Versagen entlang der Stoßfugenflucht

Masonry structures are a sustainable, economical and traditionally widely used type of construction. However, current masonry design codes are rather conservative, so there is a growing need for revision i.e. calibration of safety factors to improve the allocation of material resources. In this paper, we investigate the probability of occurrence of slip failure along head joints (perpends) in masonry subjected to in‐plane loading. An appropriate limit state function is established and the masonry material properties and loads are defined as random variables in order to simulate likelihood of occurrence of a slip failure regime along the head joints. Furthermore, an example of masonry wall with probabilistic analysis outcomes using Monte Carlo simulation is presented and recommendations for further work are provided.