Underground pipeline leak-detection method and apparatus

Abstract

This invention provides a leakage test method and a device including: marking a basic tendency of an underground line to be tested, injecting a tracer gas in a certain pressure composition of 5% hydrogen and 95% nitrogen to the line, testing the H2 signal along the tendency of the pipeline with a H2-sensitive probe of a movable hydrogen leak detector, converting the test signal to an electric signal then converting it to a digital signal by A / D conversion, memorizing and analyzing the continuously tested digital signals to judge the leakage orientation based on the change trend weak or strong of the test signal and judging the accurate position of the leak point by comparing with the maximum value of the memory and an indicator displays the maximum value of the concentration of the tested hydrogen and indicates the location of the direction and leakage definitely. Advantage: direct indication, accurate location to reduce work intensity of test.

Description

technical field [0001] The invention belongs to the field of pipeline leakage detection, and in particular relates to a method and a device for detecting underground pipeline leakage by using a hydrogen tracing method. Background technique [0002] In order to meet the production needs of urban and rural life and industrial fields, people have laid a large number of pipeline projects underground, and use these pipelines to transport water, oil, steam, gas (such as liquefied petroleum gas, natural gas) industrial products, etc. These pipelines are usually pressure pipelines. Before the newly laid pressure pipelines are put into use, pipeline leak detection is usually required to confirm that there is no leakage to ensure safe operation. In more cases, after the underground pipeline is put into use, it often causes leakage due to natural or man-made reasons such as pipeline corrosion and engineering construction, which affects people's daily life and normal production of enter...

AI Technical Summary

Problems solved by technology

For the leakage of the pipeline in operation, it is necessary to quickly and accurately find out the location of the leak point and organize on-site excavation and repair in time. The detection methods usually used include the flow balance method, the regional leak detection method, and the audio-audio method (see Chinese patents ZL94226766.4, ZL200420096839 .1 and the invention patent application with publication number CN 1808087A), related calculation methods (see Chinese patent ZL200420096159.X), etc., there are complex operations and environmental problems in terms of economy, sensitivity, accuracy, and detection effects in use. Noise interference, unsatisfactory detection results due to test conditions, expensive imported equipment, etc.

For example, the flow balance method and the regional leak detection method are complicated and cumbersome to operate, and can only judge the leaking pipe section; for the audio-audio method, it is greatly affected by environmental noise interference and the attenuation of the leakage sound propagation path, and the weak signal generated by the viscous fluid leakage is detected. The ability is poor; for the relevant calculation method, if the parameters such as pipe length and material are not accurately grasped, the use is very limited, and it is difficult to detect leaks in plastic pipelines and cement pipelines with poor noise transmission, and the cost of imported equipment is expensive

[0003] Chinese patent ZL01236193.3 discloses an "inflatable cable hydrogen leak detector", which is a device for leak detection of inflatable cables using hydrogen tracer method, which uses a hydrogen sensitive probe to convert the detected hydrogen signal into The electrical signal is directly amplified and indicated, without continuous data storage and any digital processing means. Only the signal amplitude is used as the criterion, and the detection personnel are reminded of the hydrogen content of different concentrations through the alarm. It is difficult to distinguish and determine the moving direction only by the change of the alarm volume in use. , it is necessary to constantly compare the strength of the signal received at the current position and the position just now. It is difficult to judge the change of signal strength for different sensitivity settings or different positions, and it is impossible to intuitively indicate the direction of the leak point and accurately locate it.

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