X-radiographic ellipse projection laser positioning method for small-diameter pipe

Abstract

The invention relates to an x-radiographic ellipse projection laser positioning method for a small-diameter pipe. The method includes steps of: (1) arranging an X-ray machine beside the small-diameter pipe to enable a radiation window of the X-ray machine to align with a weld and enabling a laser beam, emitted by a laser designator of the X-ray machine, to pass through the weld and to be positioned onto a laser positioning plate arranged at a film side of the weld; and (2) adjusting the angle of the radiation window to enable a distance g to be controlled within a range from 3mm to 10mm, wherein the distance g is between a laser projection point on the laser positioning plate and an edge of the weld. The invention, aiming at installation and maintenance of the small-diameter pipe of a boiler in an electric power system, provides the ray method which is suitable for an on-site operation. The method improves work efficiency and ensures detection quality.

Description

technical field [0001] The invention belongs to the technical field of power system power generation and power equipment manufacturing and processing, in particular to a small-diameter tube X-ray photographic ellipse projection laser positioning method. Background technique [0002] Small-diameter tubes are the core components of boiler heat exchange in power plants. Due to their poor working conditions, the leakage of small-diameter tubes often leads to shutdown of the boiler, resulting in major economic losses. Therefore, preventive inspection of small-diameter tube welds is carried out through various non-destructive testing methods It is very important, and it is also one of the main detection items for boiler metal supervision and inspection. [0003] The eccentric distance method is generally used to image the ellipse of the weld seam during on-site photography. The opening width of the ellipse is controlled according to the distance between the focus of the ray and th...

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Problems solved by technology

[0003] The eccentric distance method is generally used to image the ellipse of the weld seam during on-site photography. The opening width of the ellipse is controlled according to the distance between the focus of the ray and the center plane of the weld seam. The calculation formula for the opening, S 0 =(b+q)L 1 / L 2 ,S 0 — translational distance; L 1 —Transillumination distance; L 2 —the diameter of the projected small pipe; b—the height of the weld; g—the distance between the openings, but L is limited by the environment on site 1 Changes occur frequently. If measurement and calculation are required for each transillumination, the working time will be greatly increased and the work efficiency will be reduced. It is not suitable for on-site inspection of small-diameter pipes.

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