Fast checking method for pipe defect and nondestructive testing apparatus

Abstract

The invention relates to a fast scanning method of pipeline drawbacks and a non-destructive detection device, which is more particularly suitable for fast scanning and non-destructive detection of drawbacks of the pipelines with insulation. The invention is composed of a guided wave sensor, a transmitting module, a receiving module, a signal generating module, a power amplifying module, a signal processing module, an A / D conversion module and an built-in computer system. The invention is suitable for comprehensive detection of drawbacks of pipelines with different diameters, detection of long distance pipelines, and detection of pipelines in inaccessible places. The invention has the advantages of fast and large-scale detection ability without contact, high efficiency; overcoming a plurality of limitations of the conventional non-destructive detection method; overcoming the restriction conditions of oil pollution, fouling, bending or heat insulation protective layer, judging and locating the drawbacks of the pipelines, reducing the maintenance range, avoiding unnecessary disassembly and replacement, reducing the intensity of artificial detection, and saving the human and material resource. In addition, the invention can achieve on-line monitoring, and evaluate the health condition of the element or predicts the service life of the element.

Description

Technical field [0001] The invention belongs to the technical field of non-destructive testing, in particular to a method for quickly scanning pipeline defects and a non-destructive testing device for pipelines with coating layers. Background technique [0002] Coated pipes are widely used in petroleum, chemical, metallurgical, natural gas, thermal power, nuclear power and heating industries or sectors, and the purpose is to transport various fluid media such as oil, water, gas, steam, etc. Since the fluid medium to be transported has the characteristics of high humidity, high pressure, high temperature and corrosion, the pipeline is not only corroded by the external conditions caused by the external corrosion of the pipe, but the pipe wall is easily thinned due to the erosion and corrosion of the fluid. The formation of chemical deposits (such as scale, etc.) of the liquid in the pipes can easily reduce the pipeline's ability to transport fluids and even block the pipes. The lon...

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Problems solved by technology

But for the detection of long-distance pipelines, especially buried pipelines, because torsional waves travel slower than longitudinal waves in pipelines (the propagation speed of torsional waves is about 3.2×10 3 m / s, the longitudinal wave propagation speed is about 5.3×10 3 m / s), the torsional wave is much shorter than the longitudinal wave in the pipeline (the torsional wave can propagate about 30 meters away, while the longitudinal wave can propagate about 100 meters in a single direction along the pipeline)

[0007] 3. It is not suitable for online detection due to the need to remove the coating layer

[0008] 4. The quantitative detection effect is not good, and the type, distribution, size and other information of defects cannot be judged

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