Double-periphery external CT detection device based method and system for on-line detection of large-diameter pipe wall

Abstract

The invention relates to a double-periphery external CT detection device based method and system for on-line detection of a large-diameter pipe wall. The system includes an X-ray source, an area array detector I and an area array detector II, and a control and image processing system. The signal lines of the X-ray source and area array detector are connected to the control and image processing system. A circular orbit is fixed in the pipeline, so that the center of the circular orbit superposes with the center of circle of a cross section of the pipeline and the overlap; the X-ray source, area array detector I and area array detector II are respectively fixed on the circular orbit; the area array detector array detectors I and II are symmetrically arranged on both sides of the pipeline in offset arrangement, so that a cone beam produced by the X-ray source covers the outer wall area of the pipeline. The invention can scan and reconstruct the image of the outer annular region of the larger-diameter pipeline by using low-energy ray and smaller size detector; the ray beam has smaller field angle, and good ray consistency; and the invention can be used for reconstruction of the three-dimensional image of external annular region of pipeline wall (including fixed pipe).

Description

technical field [0001] The invention belongs to the technical field of pipe wall defect detection, and relates to a method and system for online detection of large-diameter pipe walls based on a double-circumference external CT (Computed Tomography, computerized tomography) detection device. Background technique [0002] Pipeline transportation has been widely used in petroleum, chemical, metallurgy, pharmaceutical, energy and environmental protection industries, and has become the lifeblood of modern industry and national economy. Pipeline transportation is responsible for the transportation of high temperature, high pressure, flammable, explosive and toxic media. Once leakage or explosion occurs due to the existence of defects, it may lead to catastrophic accidents. During the production, processing and use of pipelines, there will inevitably be defects such as corrosion, cracks, and pores. Therefore, the use of non-destructive testing technology to implement periodic acti...

AI Technical Summary

Problems solved by technology

Limited to the detection conditions of the large-diameter pipe wall in service, the distance from the ray source to the center of rotation is not large enough and the diameter of the object to be detected is relatively large. If the opening angle of the ray beam is large, the difference between the edge ray intensity and the central ray intensity is large. These It is difficult to meet the application conditions of traditional external CT; if the detector is only placed on one side of the object, the opening angle of the ray beam is smaller, but the collected ray projection data is half that of traditional external CT, which may affect the outer ring area of ​​the object image reconstruction quality

Images