IMPROVED PIPELINE INSPECTION USING LINESCANNING

WELD QUALITY AND WELD INSPECTION ARE MAJOR CONCERNS OF PIPELINE CONSTRUCTION. PRESENT INSPECTION METHODOLOGY REQUIRES SIGNIFICANT TIME DELAYS BETWEEN WELDING AND ACCEPTANCE OF THE WELD. THE COST OF THESE DELAYS IS ENORMOUS CONSIDERING THAT PIPELINE COSTS RUN UPWARDS OF $10 6/MILE AT RATES OF APPROXIMATELY 10 MILES/WEEK. ON-LINE MONITORING CAN BE EXPECTED TO PROVIDE A MINIMUM OF 10% ACCELERATION IN PROJECT SCHEDULE WITH ASSOCIATED BENEFITS IN BETTER INSPECTION QUALITY, RECORD KEEPING AND FEEDBACK TO THE WELDING SYSTEM. AN INNOVATIVE APPROACH TO THIS INSPECTION PROBLEM IS TO FOLLOW THE WELDING PROCESS WITH A LINESCAN X-RAY IMAGING SYSTEM DESIGNED TO OPERATE ON THE HOT WELD. THE X-RAY GENERATOR, X-RAY CONVERTER SCREEN AND LINESCAN CAMERA SYSTEM MUST BE DEVELOPED FOR COMPACT SIZE, SENSITIVITY TO APPLICABLE INSPECTION CODE REQUIREMENTS, AND ENVIRONMENTAL RUGGEDNESS. THE SYSTEM WILL AUTOMATICALLYSCAN THE PIPE WELD FOLLOWING EACH PASS OF THE AUTOMATIC WELDER OR BE USED TO INSPECT THE ROOT PASS AND FINAL PASS OF MANUAL WELDERS. THE LINESCAN DATA WILL BE IN VIDEO FORMAT FOR DISPLAY AND STORAGE. THIS IMAGING FORMAT READILY ALLOWS IMAGE PROCESSING FOR IMPROVED DEFECT ANALYSIS AND FITNESS-FOR-SERVICE ESTIMATIONS. THE PHASE I STUDY WILL ESTABLISH THE REQUIRED PERFORMANCE PARAMETERS AND PROVIDE AN INITIAL DESIGN FOR THE DETECTOR SYSTEM. PHASE II EFFORT WILL DEVELOP A TOTAL SYSTEM.