Leak tightness of bolted flange gasketed joints and stuffing box packings

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It is well established that the major cause of failure of bolted joints and valves is leakage. The latest North American survey showed that leakage from these two pressure vessel components represents an important amount of the total fugitive emissions produced by industrial equipments. The gaskets and stuffing box packings used as sealing elements in these equipments are not the only parameters to blame. With today's increasing environmental consciousness and strict environmental protection laws, attention has focused not only on improving sealing products, but also implementing better design calculation methods that minimize fugitive emissions from industrial process equipments. While over the years the validity of the current extensively used flange design method has raised increasing inquiries, there is no documented design method for stuffing boxes. Even though a substantial effort has been put towards reducing fugitive emissions, preventing leakage remains one of the biggest challenges. A fundamental understanding of the general behaviour of the gasket in a bolted joint or the compression packing in a stuffing box must be conducted in order to delimit the leakage controlling parameters. Our recent studies on gaskets show that their performance depends not only on the working conditions (pressure and temperature), but also on the mechanical components (rigidity, facing geometry, surface roughness) on which they are mounted. The proposed research project aims at improving gaskets and optimizing their general performance within the equipment they are used. Its objective is to pursue fundamental research work on bolted gasketed joints. In parallel, it is our goal to extend the gained knowledge to the study of stuffing box packings. Although, the application is different, the leakage flow mechanism of pakings is practically controlled by similar parameters such as contact pressure, surface roughness, geometry, type of fluid and temperature. An important part of the work will be devoted to the development of analytical models and numerical FEM models. These models will be validated experimentally on real bolted gasketed joints and stuffing box packings.