A study of negative pressure wave method based on Haar wavelet transform in ship piping leakage detection system

2011 ◽  
Author(s):  
Zhongbo Peng ◽  
Jie Wang ◽  
Xuefeng Han
Keyword(s):  
Wavelet Transform ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Detection System ◽  
Haar Wavelet ◽  
Wave Method ◽  
Leakage Detection ◽  
Haar Wavelet Transform ◽  
Negative Pressure Wave

scholarly journals An Improved Negative Pressure Wave Method for Natural Gas Pipeline Leak Location Using FBG Based Strain Sensor and Wavelet Transform

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Qingmin Hou ◽  
Liang Ren ◽  
Wenling Jiao ◽  
Pinghua Zou ◽  
Gangbing Song
Keyword(s):  
Wavelet Transform ◽  
Natural Gas ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Strain Sensor ◽  
Wave Method ◽  
Positioning Accuracy ◽  
Natural Gas Pipeline ◽  
Leak Location ◽  
Negative Pressure Wave

Methods that more quickly locate leakages in natural gas pipelines are urgently required. In this paper, an improved negative pressure wave method based on FBG based strain sensors and wavelet analysis is proposed. This method takes into account the variation in the negative pressure wave propagation velocity and the gas velocity variation, uses the traditional leak location formula, and employs Compound Simpson and Dichotomy Searching for solving this formula. In addition, a FBG based strain sensor instead of a traditional pressure sensor was developed for detecting the negative pressure wave signal produced by leakage. Unlike traditional sensors, FBG sensors can be installed anywhere along the pipeline, thus leading to high positioning accuracy through more frequent installment of the sensors. Finally, a wavelet transform method was employed to locate the pressure drop points within the FBG signals. Experiment results show good positioning accuracy for natural gas pipeline leakage, using this new method.

Pipeline Leak Detection Based on Double Sensor Negative Pressure Wave

2013 ◽  
Vol 313-314 ◽  
pp. 1225-1228 ◽  
Author(s):  
Chun Xia Hou ◽  
Er Hua Zhang
Keyword(s):  
False Alarm ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Detection System ◽  
Low Frequency ◽  
Leak Detection ◽  
Frequency Component ◽  
Economic Losses ◽  
Single Sensor ◽  
Negative Pressure Wave

Pipeline leak lead to huge economic losses and environmental pollution. Leak detection system based on single sensor negative pressure wave often causes false alarm. In this paper the double sensor method is adopted to exclude false alarm by determining the propagation direction of the pressure wave. In order to remove the inverse coherent interference caused by pump running, the phase difference of primary low frequency component is used to identify the sign of the time delay between the double sensors. The experiment shows the mothod is effective.

Effect of rubber washers on leak location for assembled pressurized liquid pipeline based on negative pressure wave method

2018 ◽  
Vol 119 ◽  
pp. 181-190 ◽  
Author(s):  
Qiang Chen ◽  
Guodong Shen ◽  
JunCheng Jiang ◽  
Xu Diao ◽  
Zhirong Wang ◽  
...  
Keyword(s):  
Negative Pressure ◽  
Pressure Wave ◽  
Wave Method ◽  
Leak Location ◽  
Negative Pressure Wave

A Petroleum Pipelines Leakage Monitoring System

2004 ◽  
Author(s):  
Zhuang Li ◽  
Shijiu Jin ◽  
Likun Wang ◽  
Yan Zhou
Keyword(s):  
Monitoring System ◽  
Negative Pressure ◽  
Pressure Wave ◽  
Wave Speed ◽  
Freezing Point ◽  
Oil Field ◽  
Wave Method ◽  
Negative Pressure Wave ◽  
Leakage Monitoring ◽  
Petroleum Company

The petroleum leakage has been a serious problem these years in China. The leakage, mostly caused by human destruction, lasting a short time with a large amount of loss, is not only an economic loss for the petroleum company, but environmental pollution, a public issue. Thus a monitoring system, which can identify the leakage and locate the leak point in real time, is required. One of the challenges is the sensitivity of the system. The system is expected to respond quickly to locate the point so that the security personnel can find and mend the orifice in time. Another challenge is the accuracy of the locating result. Because of the features of Chinese petroleum: high viscosity, high wax content and high freezing point, the sound wave speed in the oil is not a constant along the pipeline and the leak point calculated by the traditional negative pressure wave method are invalid. In this paper, a modified negative pressure wave method was put forward according to the variation of the wave speed. A wavelet-based algorithm applied to calculate the leak point gives fairly satisfied results. The data acquisition, signal processing and the structure of the pipeline leakage monitoring system (PLMS) were analyzed. The system has played a big role on the pipeline network in Shengli Oil Field and long pipelines of East China Oil Bureau.

Monitoring of Natural Gas Pipeline Leaks

2010 ◽  
Author(s):  
Dongliang Yu ◽  
Likun Wang ◽  
Bin Xu ◽  
Hongchao Wang ◽  
Min Xiong ◽  
...  
Keyword(s):  
Acoustic Wave ◽  
Negative Pressure ◽  
Pressure Measurement ◽  
Pressure Wave ◽  
Wavelet Packet ◽  
Wavelet Packet Decomposition ◽  
Wave Method ◽  
Decomposition Technique ◽  
Natural Gas Pipeline ◽  
Negative Pressure Wave

Pipe is a very important tool for long-distance transportation of nature gas. In the long-term running, there will be inevitably an appearance of a rupture, leak or damage usually caused by manmade event or by nature disaster. Leaks may generate dangerous clouds of gas escaping from the high-pressure pipe and produce serious incidences involving fire and explosion endangering the life and property safety of people in and around the area. Monitoring of natural gas pipeline leaks will timely find out and locate these dangerous occurrences and reduce loss. Within the leak monitoring, the core contents are the accurate location of leaks as well as the rapid identification of different signal sources reducing false alarm ratio. Once a leak occurs, the supersonic jet of escaping gas can generate a non-linear & chaotic negative pressure wave signal based on static pressure measurement and an acoustic signal based on dynamic pressure measurement [1]. By properly interpreting these two kinds of signals together, it is possible to detect and locate the leak along the pipe. However, useful signals usually mix in the powerful backdrop signals and noises. In order to resolve the problem, the wavelet packet decomposition technique [2] is used to reduce the noises and get the feature signals of negative pressure wave and acoustic wave. Furthermore, a lot of different condition regulating signals for instance compressor start-stop, valve adjusting and gas turbulence can interfere with the accurate identification of leaks and result in false alarm. It is quite required to classify these similar signals. Thus, BP neural network [3] is used to quickly recognize the different pressure fluctuation signals. Finally, an integrated system developed by LabView is introduced to timely monitor the operation condition and locate the leak. Field tests indicate this system using negative pressure wave method, acoustic wave method, wavelet packet decomposition technique as well as BP network has a good effect.

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