Helium leak detectors: from a laboratory device to dedicated industrial leak test units

Bley, Werner Große

doi:10.1016/0042-207x(93)90112-n

Cited by 15 publications

(5 citation statements)

References 4 publications

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“…In each detection, the distance from the leak to the sensor plane (L p ) is considered to be approximately constant, because only the direction of the sensor plane is adjusted. When the leak is found, the location error L e is measured as the distance between the leak and the projection of the laser beam on the wall, and the direction error θ e is obtained from equation (5). Both the TDEULD and the DULD of our own design are implemented in this experiment for comparison.…”

Section: Methodsmentioning

confidence: 99%

“…Various leak detection methods have been developed and applied to leak-tight testing or pipeline leak detection, which include bubble immersion [3], radioisotopes [4], helium sniffing [5], halogen sniffing [6], flow measurement [7], differential pressure measurement [8], thermal conductivity [9], acoustic beamforming [10], ultrasonics [2,[11][12][13][14], etc. Among these leak detection methods, the ultrasonic method is widely used in compressed air leak detection, due to its simplicity, convenience, high efficiency and ability to find a wide variety of leaks.…”

Section: Introductionmentioning

confidence: 99%

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Compressed air leak detection based on time delay estimation using a portable multi-sensor ultrasonic detector

Liao

Cai

Shi

et al. 2013

Meas. Sci. Technol.

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The conventional ultrasonic method for compressed air leak detection utilizes a directivity-based ultrasonic leak detector (DULD) to locate the leak. The location accuracy of this method is low due to the limit of the nominal frequency and the size of the ultrasonic sensor. In order to overcome this deficiency, a method based on time delay estimation (TDE) is proposed. The method utilizes three ultrasonic sensors arranged in an equilateral triangle to simultaneously receive the ultrasound generated by the leak. The leak can be located according to time delays between every two sensor signals. The theoretical accuracy of the method is analyzed, and it is found that the location error increases linearly with delay estimation error and the distance from the leak to the sensor plane, and the location error decreases with the distance between sensors. The average square difference function delay estimator with parabolic fitting is used and two practical techniques are devised to remove the anomalous delay estimates. Experimental results indicate that the location accuracy using the TDE-based ultrasonic leak detector is 6.5–8.3 times as high as that using the DULD. By adopting the proposed method, the leak can be located more accurately and easily, and then the detection efficiency is improved.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Compressed air leak detection based on time delay estimation using a portable multi-sensor ultrasonic detector

Liao

Cai

Shi

et al. 2013

Meas. Sci. Technol.

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show abstract

“…Permeation and capillary leaks [31][32][33][34][35] are the most diffused standard leaks and helium is commonly used as tracer gas. The first type can be used to generate gas flow rates from 10 À12 Pa m 3 /s to 10 À4 Pa m 3 /s.…”

Section: Reference Leaksmentioning

confidence: 99%

Leak rate metrology for the society and industry

Bergoglio

Mari

2012

Measurement

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“…Laboratories usage, such as carrier gas for gas chromatography, powder carrier gas for thermal spraying, cold spraying, and use in thermoacoustic heat pumps are other fields of helium applications [1]. Important applications for helium also include pressurizing liquid fuel for missiles [6,7], deep-sea divers breathing mixtures to avoid nitrogen narcosis [8][9][10], lighterthan-air systems [3,[11][12][13], and leak detection [14,15]. The most well-known party application (i.e., filling balloons) has only contributed to about 8 % of helium's total consumption worldwide.…”

Section: Introductionmentioning

confidence: 99%