Hyperbolic boiler tube leak location based on quaternary acoustic array
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Leak Detection
Steam leakage is one of the major issues for the structural fracture of pipes of nuclear power plants. Therefore a method to inspect a large area of piping systems quickly and accurately is needed. In this paper, we proposed the method for the detecting steam leakage by using image signal processing. Our basic idea come from heat shimmer which shine with a soft light that looks as if it shakes slightly. To test the performance of this technique, experiments have been performed for simple heat source and steam generator. Results show that the proposed technique is quite powerful in the steam leak detection.
Leak Detection
Leakage (economics)
SIGNAL (programming language)
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The leakage-induced acoustic vibrations are guided by the pipelines and discretized into several modes. Different modes exhibit different dispersive behaviors and generate vibrations of different directions. In this study, the modal characteristics of acoustic vibrations in different directions are investigated theoretically and experimentally. The dispersive natures and the displacement distributions of the guided wave modes in fluid-filled pipelines are analyzed using the guided wave theory. Theoretical analysis predicts that the axial vibrations are dominated by a single non-dispersive longitudinal mode, while the radial and circumferential vibrations are dominated by more than one dispersive modes respectively in the frequency range 0–2.5kHz. Then the experimental investigations convince the theoretical predictions and demonstrate that the axial vibrations are dominated by an individual non-dispersive guided wave with small attenuation rate in the frequency region 0–2.5 kHz. These discoveries demonstrate that, at information acquisition stage, exclusively picking up the axial vibration can significantly improve leak detection and location in the pipelines compared to the conventional detection of the radial vibration.
Leakage (economics)
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In this preliminary paper, we present a spatial filtering technique based on the wave equation for an one-dimensional waveguide and apply it to extract an acoustic leak signal, which is a symptom of a leak from a pipeline system, embedded in severe background noises. Two sets of sensor array, each of which consists of a pair of PVDF film elements, are installed at the both ends of the monitoring interval, so that the measured wave motions are decomposed into positive and negative traveling wave components. After an appropriate processing of these traveling waves, the background noises, which come from outside of the monitoring interval, are canceled and only the leak signal remains. Some preliminary experiments show that the proposed method can provide 10–100 times progress in the S/N ratio even if both the leak signal and the background noise are in the same frequency band.
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This paper describes generally the status of boiler tube leak knowkedge and its application, from the three points of view: the leak mechanisms, the leak detection methods and the diagnose technology of the remaining life. And the boiler leak expert system is also discussed briefly.
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This article discusses the use of a detection system to pinpoint leaks in a steam generator in time to prevent damage from steam washing, cutting, or overheating. The topics of the article include the need for timely leak detection, traditional methods, high frequency acoustic emission leak detection, complete boiler coverage, major components of the system, and an overview of its operation.
Overheating (electricity)
Leak Detection
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Gas or water leaks in pipes that are buried under ground or that are situated in the walls of buildings may occur due to aging or unpredictable accidents, such as earthquakes. Therefore, the detection of leaks in pipes is an important task and has been investigated extensively. In the present paper, we propose a novel leak detection method by means of acoustic wave. We inject an acoustic chirp signal into a target pipeline and then estimate the leak location from the delay time of the compressed pulse by passing the reflected signal through a correlator. In order to distinguish a leak reflection in a complicated pipeline arrangement, the reflection characteristics of leaks are carefully discussed by numerical simulations and experiments. There is a remarkable difference in the reflection characteristics between the leak and other types of discontinuity, and the property can be utilized to distinguish the leak reflection. The experimental results show that, even in a complicated pipe arrangement including bends and branches, the proposed approach can successfully implement the leak detection. Furthermore, the proposed approach has low cost and is easy to implement because only a personal computer and some commonly equipment are required.
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Leak Detection
Discontinuity (linguistics)
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Boiler tubes in power plants are often leaked due to various material degradations including creep and thermal fatigue damage under severe operating conditions such as high temperature and high pressure over an extended period of time. To monitor and diagnose the tubes on site and in real time, the acoustic emission (AE) technology was applied. We developed an AE leak detection system, and used it to study the variation of AE signal from the on-site tubes in response to the changes in the boiler operation condition and to detect the locations of leakage based on it. Detection of leak was performed by acquiring and evaluating the signals in separate regimes of high and low frequency signal. As a result of these studies, we found that on-line monitoring and detection of leak location for boiler tubes is possible using the developed system. Thus, the system is expected to contribute to the safe operation of power plants, and prevent economic losses due to potential leak.
Acoustic Emission
Leak Detection
Leakage (economics)
Condition Monitoring
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Leakage (economics)
SIGNAL (programming language)
Leak Detection
Acoustic Emission
Echo (communications protocol)
Gas leak
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