System for Assembly of Flanged Joints

A method for the control and monitoring of the assembly of a bolted flanged joint, the bolted flanged joint including a first flange having a first sealing surface, a second flange having a second sealing surface, a gasket between the first flange and the second flange, and at least four bolts to retain together the flanges and the gasket of the bolted flanged joint when assembled, the method including the steps of:

• obtaining directly or indirectly at three or more points around the flanges a flange gap between the first flange and the second flange to determine a respective three or more flange gap measurements;
• calculating from the three or more flange gap measurements an initial misalignment between the first flange and the second flange or between the first sealing surface and the second sealing surface;
• if the initial misalignment is greater than a predetermined magnitude of misalignment, then:
• determining from the initial misalignment which of the at least four bolts is the first bolt to tighten;
• setting an initial tightening torque or tightening load for a bolt load applicator;
• indicating the first bolt to tighten using a bolt assembly pattern indicator;
• beginning initial tightening of the first bolt;
• monitoring nut or bolt head rotation to check for issues and halting joint assembly if issues detected;
• monitoring the flange gap measurements;
• if the monitoring of the flange gap measurements indicates that the misalignment has been corrected, then commencing a standard bolt tightening pattern by indicating a second bolt to tighten;
• if the monitoring of the flange gap measurements indicates that the misalignment has not been corrected when the initial tightening torque or tightening load is reached on the first bolt, then obtaining the flange gap at the three or more points around the flange to obtain a respective three or more flange gap measurements, calculating a current misalignment then determining from the current misalignment which of the at least four bolts is the second bolt to tighten, then repeating the indicating, tightening and monitoring steps of the first bolt for the second bolt, then if misalignment has not been corrected after at least one third or one quarter of the bolts have been initially tightened, halting joint assembly;
• if misalignment has been corrected, then commencing a standard bolt tightening pattern;
• if the initial misalignment is less than the predetermined magnitude of misalignment, then commencing a standard bolt tightening pattern.