Sealing design material selection

The mine idler s failure work presents by inflexibility or stuck. The practical experience requires a good performance of idler s life, reliability, rotational resistance, sealing performance, as well as noise and vibration. To address these requirements, one must control strictly various aspects as the design, material selection, manufacturing, assembly, testing and working environment. However,... 

The existence of these imperfections, recognized by the presence of voids, scratches and machine striations, allows micro pathways to exist through which fluid, often under pressure, can flow, thus causing a leak. In conventional engineering design practice these pathways are sealed by deforming a softer material between the two surfaces being sealed. The seal, and the selection of the material, is dictated usually by three factors, namely ... 

Both the CNIS/Gc ratio (Fig. 6.14a) and the seale factor (Fig. 6.14b) decrease substantially with the MAH concentration for the composites with complete separation. This behavior suggests that single values of CNIS are of little value for a comparison of relative toughness of materials of different eomposition or as a parameter for material selection and product design. In these eases, a fracture mechanics approach should be carried out to make comparisons of materials with different degree of adhesion relative to an equivalent state of stress. 

PEM fuel cells have emerged as the most common type of fuel cell under development today. As stated above, they also are commonly referred to as proton exchange membrane fuel cells based on the key characteristic of the solid electrolyte membrane to transfer protons from the anode to the cathode. The solid electrolyte avoids problems caused by liquid electrolytes used in other systems, and the temperature range of <100°C enables rapid start-up under low temperature operation, with operation possible down to subfreezing temperatures. The lower temperature also allows a wider range of materials to be used and enables relatively easy stack design in terms of sealing issues and material selection. This type of fuel cell is the most feasible for use under transportation applications. 

Tubular or box shapes should be used whenever possible to minimize edges and inside corners. If possible, the metallic materials selected should have the best resistance to corrosive attack or be alloyed to enhance coatings performance. A particular attention to design should be made to minimize the dwelling time of atmospheric condensation and provide special attention to surfaces shaded from the sun [5]. Large enclosed spaces that have not been totally sealed, such as the insides of box girders, should be coated, or ventilated, with fans if necessary. Decisions on coatings should not be left to the casual attention of inexperienced personnel. It is quite clear that... 

Conventional seal designs/novel materials selections ... 

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