PROCEDURE DETERMINING LOCAL DISPLACEMENT OF TRUNK PIPE- LINES Russian patent published in 2003 - IPC

FIELD: test and diagnostics of pipe-lines, evaluation of values of vertical and horizontal displacement of their axes with the aid of intrapipe inspection tools. SUBSTANCE: procedure includes determination of three components of vector of absolute angular velocity and apparent acceleration of intrapipe inspection tool with the help of platform-free orientation and navigation system, of increments of its path with the use of odometer and of its position with reference to pipe-line with the aid of ultrasonic pickups. Measurement results are entered into storage of computer. Intrapipe inspection tool is passed n times through one and same section of pipe-line in time intervals characterized by various steady temperature and weather conditions. During each passage momentary temperature and profile along circumference of pipe are established in 8 equally distance points, as minimum, and entered into computer as function of present time and distance covered as well as gas pressure on front and rear walls of intrapipe inspection tool. On execution of n passages of intrapipe inspection tool stationary computer determines increments of all measured parameters with respect to corresponding parameters of first passage as well as gradients of temperature in horizontal and vertical planes for similar points of welds referenced to plane of horizon. Geographic coordinates of reference points of pipe-line are established by means of stationary computer by signals of transmitters of global positioning system and inertial orientation and navigation system with due account of signals of odometer of tool and welds of pipe-line. Parameters of drift of inertial system by which correction to its functioning algorithm is entered are determined by exposed difference of three coordinates of corresponding reference points and local displacement of pipe-line is computed. EFFECT: possibility of determination of local displacement of sections of gas pipe-line in geographic or geodetic coordinates for detection and prediction of stress corrosion and dangerous mechanical stresses in them. 3 cl, 3 dwg