Method for measuring residual thickness of metal pipeline or metal pressure container after local corrosion

A technology for pressure vessels and metal pipes, which is applied in the field of measurement and can solve problems such as large errors

Active Publication Date: 2013-12-25
四川思科锐德智能科技有限公司 +1
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  • Summary
  • Abstract
  • Description
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  • Application Information

AI Technical Summary

Problems solved by technology

The existing formula for calculating the remaining thickness of the field fingerprint method ignores the current change problem when calculating the local corrosion, and thinks that the current flow of the local corrosion is the same as that of the uniform corrosion, which brings a large error

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  • Method for measuring residual thickness of metal pipeline or metal pressure container after local corrosion
  • Method for measuring residual thickness of metal pipeline or metal pressure container after local corrosion
  • Method for measuring residual thickness of metal pipeline or metal pressure container after local corrosion

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Embodiment Construction

[0062] The present invention will be described in detail below with an example.

[0063] see figure 1 , in this example, the pipe thickness is 10mm, the inner diameter is 304mm low carbon steel straight pipe, based on the principle of field fingerprint method, the measurement electrode probe matrix is ​​set on the outer wall of the metal pipe, the reference electrode pair is set on the reference plate, and the measurement electrode probe In the matrix, the probes in the circumferential direction of the pipeline are i=16 rows, and the probes in the axial direction are j=7 columns. Any two adjacent probes in the axial direction constitute a probe pair, which is used as a measuring electrode. Follow the steps below Measuring remaining thickness of localized corrosion in pipes:

[0064] (1) Input a constant current of 8A to the pipeline through the reference board. The current can be DC or AC with a frequency not greater than 20Hz. The distance between the current injection and o...

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Abstract

The invention discloses a method for preciously detecting/monitoring the residual thickness of a metal pipeline or a pressure container after local corrosion based on a field fingerprint technique. The method comprises the following steps: obtaining a sampling voltage through using a measure electrode probe matrix and a reference electrode, calculating according to the sampling voltage to obtain a field fingerprint coefficient FC, sequentially calculating pipeline resistance values of positions in which all probes are positioned, calculating current values of all resistors, calculating a current value of a column in which a resistance change appears to an adjacent column, and finally calculating the residual thickness of the pipeline or the pressure container after local corrosion. The method greatly improves the detection precision, can be used for certainly calculating the residual thickness after the local corrosion, has a higher precision than present common methods, can realize more reliable results than the present common methods, and provides reliable bases for the determination of hidden accident troubles caused by the corrosion.

Description

technical field [0001] The invention relates to a method for measuring the residual thickness of local corrosion of metal pipes and metal pressure vessels, belonging to the technical field of measurement. Background technique [0002] In the petrochemical industry, corrosion is the main cause of accidents in pipelines (such as oil and natural gas pipelines), accounting for 70% to 90% of the total number of accidents. Corrosion forms are divided into: general corrosion, local corrosion, pit corrosion, welding corrosion and erosion. At present, the petrochemical industry generally adopts resistance probe method and polarization probe method to monitor the corrosion status of pipelines online, but these methods can only detect indirect uniform corrosion, and have no ability to monitor extremely harmful localized corrosion. High-precision and high-reliability local corrosion monitoring methods and technologies are one of the technologies that are urgently needed for the safe op...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N27/20
Inventor 万正军甘芳吉许华文宋康廖俊必
Owner 四川思科锐德智能科技有限公司
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