Determination of peaking of pipes
In a method for determining the seam peaking of a pipeline, measured values of the internal pipe geometry are recorded adjacent to a sought point P of the seam peaking, at which the measurement of meaningful measured values is difficult or impossible due to a weld seam present there, and a trend is determined from the measured values and a value of the seam peaking is determined on the basis of the trend.
1 . A method for determining a seam peaking of a pipeline comprising,
measuring, with an array of ultrasonic sensors, values of an internal pipe geometry adjacent to a sought point of the seam peaking, at which the measurement of meaningful measured values is difficult or impossible due to a weld seam present there, wherein the sought point of the seam peaking is an indicator of a deviation from a theoretical roundness of the pipe that can lead to increased crack formation in and around the weld seam, wherein at least two measured values are recorded on either side of the sought point of the seam peaking in a circumferential direction of the pipe,
determining a trend from the measured values,
based on the trend, determining a value of the seam peaking,
determining an angular position of an inner wall of the pipe on either side of the sought point, and
determining, via an intersection of the angular position, the seam peaking of the sought point of the seam peaking.
2 . The method according to claim 1 , wherein values from the measured values, that were measured directly at the weld seam are not used by the method for determining the seam peaking.
3 . The method according to claim 1 , further comprising: comparing neighbouring measured values of the measured values with one another and determining outliers, wherein the outliers are an indication of a presence of the weld seam at a specific location, wherein the presence of the weld seam at the specific location is inferred from measured data from one or more previous measurements at other axial locations of the pipeline, and wherein the outliers and measured values determined in this way at locations of an expected weld seam are not used for the seam peaking determination.
4 . The method according to claim 1 , wherein at least two points of an inner surface of the pipe are determined in an circumferential direction of the pipe on either side of the sought point of the seam peaking, which are each approximated by interpolation to a straight line whose point of intersection corresponds to the seam peaking.
5 . The method according to claim 1 , wherein the trend is determined by using one of the following steps:
a) determining, using a plurality of measured values via a linear regression, the angular position or a straight line;
b) determining, by each neighbouring sensor of a sensor carrier, an inclination of the inner wall of the pipe, and determining, based on a median value of the inclination, the angular position or the straight line; and
c) determining, by spatially neighbouring sensors of the sensor carrier, an inclination of an inner wall of the pipe, checking whether the inclinations contain an outlier, and wherein only inclinations are used to form a mean value which, seen from the outlier, lie adjacent to the sought point of the seam peaking.
6 . The method according to claim 1 , wherein in an event that the seam peaking is provided with a negative sign and corresponds to a retraction, determining a mirroring of the measured values over an ideal circular arc geometry, determining the seam peaking, determining a mirroring over an ideal circular arc geometry for the determined value of the seam peaking and an extent of the retraction, is determined therefrom, where in the mirrorings are determined using a Kelvin transformation.
7 . The method according to claim 1 , wherein a sensor carrier comprises a plurality of sensors, and the sensor carrier has a width in a circumferential direction of the pipe, which corresponds to at least 70% of an expected seam peaking width, wherein the width of the sensor carrier corresponds to a maximum of 130% of the expected seam peaking width.
8 . A pig for determining a wall thickness measurement and/or a geometry measurement and/or a crack measurement in a pipe, the pig having a sensor carrier that comprises a plurality of sensors, and a control system and/or software which is configured to perform the method according to claim 1 .
9 . A computer program product comprising a non-transitory computer-readable medium loadable into a program memory, and comprising program instructions to carry out all the steps of a method according to claim 1 when the program is executed.