Diagnostics of the technical condition of heat exchangers tube bundles at hazardous production facilities during the period of shutdown maintenance is considered in the article. Possible approaches to solving the problem associated with the limited time for examination, the large total length of the tubes in bundles and the vagueness of the diagnostic features of tubes defectiveness are analyzed. Use of the traditional methods of non-destructive testing, including endoscopy, does not allow to perform control of the technical condition of heat exchanger tubes. Relatively recently, for the examination of the internal clearance of small-diameter pipes, the method of acoustic pulse reflectometry, known in science and technology, was used. PAKT-04 device was produced for express- inspection of heat exchangers. This method was implemented in the device. Experience of using the device is presented. The principle of acoustic pulse reflectometry and the characteristics of the device are reviewed in brief. The features of defects on the reflectogram and masking their interference are shown. It is proposed for characterizing the wear of the tubes to introduce a generalized quantitative parameter called the «defectiveness degree». This parameter considers the degree of erosion of the inner wall, presence of deposits, blockages, holes. It is determined by the change of signal propagating in the tube. The value of defectiveness degree indicates the applicability of the tube for operation in the heat exchanger. Examples are demonstrated related to tubes wear and the value of this parameter. The results of measuring the parameter on different heat exchangers are discussed.
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