Method and apparatus for external pipeline weld inspection

Apparatus for external inspection of a pipeline circumferential weld, comprising:

• a track for clamping circumferentially around the pipeline having a track interior surface and a track exterior surface, when the track is clamped around the pipeline the track interior surface faces toward the pipeline and the track exterior surface faces away from the pipeline;
• an x-ray detection sensor and an x-ray source each independently mounted on the track exterior surface on opposing sides of the track, the x-ray source and the x-ray detection sensor are each mounted parallel with the track exterior surface and parallel with the pipeline and are independently movable circumferentially around the track exterior surface;
• a plurality of mounting pads attached only to the track interior surface to space the track radially apart from the pipeline and to allow the x-ray detection sensor and the x-ray source to be securely mounted on the track exterior surface;
• means to move the x-ray source and the x-ray detection sensor with respect to each other clockwise and anti-clockwise around an initial position while sampling x-ray radiation detected at a number of positions to determine a position of maximum strength of the x-ray radiation signal detected, whereby the center point of the x-ray source may be located and the x-ray source and the x-ray detection sensor substantially aligned with each other;
• wherein the radiation x-ray source is collimated into a narrow fan beam illuminating the x-ray detection sensor and the detector is shielded by a radiation absorbing housing to reduce scattering of the x-ray radiation;
• and
• wherein the x-ray detection sensor and the x-ray source reside a distance above the track, such that the track is not located between the x-ray source and the x-ray detection sensor.

Apparatus for external inspection of a pipeline circumferential weld, comprising:

• a track having a track interior surface, a track exterior surface and track upper and lower surfaces, the track detachably clamps circumferentially around the pipeline whereby the track interior surface faces toward the pipeline and the track exterior surface faces away from the pipeline;
• an x-ray source assembly on a first motorized buggy and an x-ray detector assembly on a second motorized buggy each independently mounted on the track exterior surface on opposing sides of the track, the x-ray source assembly and the x-ray detection assembly are each mounted parallel with the track exterior surface and parallel with the pipeline and are independently movable circumferentially around the track exterior surface via the first and second motorized buggies, the x-ray source assembly includes an x-ray source and the x-ray detection assembly includes an x-ray detection sensor coupled to image collection equipment;
• a plurality of mounting pads attached only to the track interior surface to space the track radially apart from the pipeline and to allow the x-ray detection sensor and the x-ray source to be securely mounted on the track exterior surface via the first and second motorized buggies, the first and second motorized buggies attaching to the upper and lower surfaces of the track and residing on the track exterior surface;
• means to move the x-ray source assembly and the x-ray detector assembly with respect to each other clockwise and anti-clockwise around an initial position while sampling x-ray radiation detected at a number of positions to determine a position of maximum strength of the x-ray radiation signal detected, whereby the center point of the x-ray source may be located and the x-ray source assembly and the x-ray detection assembly substantially aligned with each other;
• wherein the radiation x-ray source is collimated into a narrow fan beam illuminating the x-ray detector and the detector is shielded by a radiation absorbing housing to reduce scattering of the x-ray radiation;
• and
• further comprising means for moving the x-ray source assembly and the x-ray detector assembly circumferentially around the pipeline whilst remaining substantially in alignment,
• wherein the x-ray detection sensor and the x-ray source are mounted on their respective assemblies at positions longitudinally spaced away from the track, such that the track is not located between the x-ray source and the x-ray detection sensor.