A KNOWLEDGE BASED SYSTEM' FOR- THE SELECTION AND DESIGN OF FLANGES, FOR PRESSURE VESSELS

Abstract

Bolted-flanged joints, are one of the main accessories, of the pressure vessel. They used to join the two parts of the vessel and also permit disassembly and cleaning of the internal parts. Flanges are also used for making connection for piping and nozzle attachments. Selection an,d.design of bolted-flanged joint includes selection of type of flange, bolt material, gasket material and designing of flange hub specifications, flange ring thickness, gasket dimensions, bolt size and number of bolts etc. Flanges for pressure vessels are usually designed as per ASME Boiler and Pressure Vessel Code section VIII Division 1/ Division 2 and TEMA. Flanges for pipes are selected according to ANSI B16.5 and API 605. Complete selection and design of flange is a time consuming process manually because it. involves processing vast amount of data and use of rough design-rules. Also manual design involves looking into different tables, graphic data and may involve human errors and has become a cumbersome job. Therefore, a knowledge-based system for the selection and design of flange, assumes great importance to bridge gap between a general engineer and tie available knowledge in this subject area and to reduce human efforts, time and cost. In view of the above, two knowledge based system "FLEX!" and "FLEX2" have been developed. "FLEX!" concerns with the selection and design of flanges for pressure vessels and "FLEX2" deals with selection of flanges for pipes. The software "FLEXIt has got some additional features as compared to other commercial softwares available. These additional features include automatic selection of type of flange, bolting material with its allowable stress according to ASME section II, bolt size,gasket material with gasket factor and gasket seating stress. "FLEX1" also provides information on flange ring thickness, flange weight, external load and moment consideration due to wind or seismic condition, design for full-face gasketed slip on flange, allowable stress for specified flange material, graphic display of sectional view of flange and presentation of results on standard format for calculation checking. (