Leak Testing


Also found in: Acronyms.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Leak Testing

 

in vacuum technology, the detection of the site of failure of the hermetic sealing in a vacuum system by means of instruments called leak detectors.

The simplest technique for locating leaks uses a discharge leak detector, which detects leaks in glass walls by means of the spark generated when the probe of the detector touches the defective site. The smallest leak detectable with such instruments is estimated at 10–4 Newton meter per sec (10–3 liter mm Hg per sec).

Mass spectrometers are used to discover smaller leaks in walls made of glass and other materials, such as metals. A leak is located by the penetration of a tracer gas, usually helium, which is sprayed on the walls of the system. A mass spectrometer that detects helium is integrated with a vacuum system, and the presence and magnitude of the leak are determined from the reading of the recording device on the mass spectrometer. Helium detectors can detect leaks of 10–15 Newton meter per sec (10–14 liter mm Hg per sec). Other tracer gases, such as argon, are also used.

Certain leak detectors use a halogen as a tracer gas. Their operation is based on the emission of alkali metal impurities as ions by several metals, such as Pt and Ni, when the metals are heated. Such emission increases in the presence of halogens, thus causing surface ionization. Freons are most often used as the tracer gas in such detectors. The presence and magnitude of a leak are determined from changes in the ion current. Halogen detectors can discover leaks as small as 10–9 Newton meter per sec (10–8 liter mm Hg per sec).

Other methods of leak testing, such as the use of luminescent substances and tracer atoms, are less commonly used.

REFERENCE

Lanis, V. A., and L. E. Levina. Tekhnika vakuumnykh ispytanii, 2nd ed. Moscow-Leningrad, 1963.

L. E. LEVINA

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Leak testing is key to achieving quality throughout the production process from battery cell manufacture to vehicle assembly.'
It is particularly suitable for leak testing large-volume objects such as piping, valves, heat exchangers,
This inherent permeability of many components effectively relegates tracer gas efforts to leak testing. Only in certain cases, it may be possible to design single-use assemblies for in situ tracer gas testing, allowing pre-use leak testing at the point of use (post-deployment) with a high degree of sensitivity.
A new multi-channel leak detector reportedly achieves unprecedented test speeds for lower-cost leak testing in high-volume production.
As pipe sizes become larger and the products inside them become more aggressive, the criteria for selecting plugs for product-isolation purposes and for pipe-work leak testing have had to be upgraded, according to Huntingdon Fusion.
As pipe sizes become larger, and as the products inside them become more aggressive, the criteria for selecting plugs for product isolation purposes and for pipe-work leak testing have had to be upgraded.
"Switching from leak testing with helium to leak testing with diluted hydrogen has been all positive for us," says Philip Stephenson, senior procurement engineer for Hill Phoenix.
This capabilities brochure highlights the company's extensive experience in pressure decay, mass flow, helium accumulation and mass spectrometer leak testing. The brochure also recognizes typical applications for the company's equipment and solutions that include automotive components, other transportation components, medical components and consumer products.
The leak testing regime set out in the F-gas legislation calls for all chillers or air conditioning systems with a refrigerant charge of 3kg but under 30kg to be leak tested annually (though for hermetically sealed compressor systems annual leakage checks are carried out 6kg up to 30kg), from 30kg up to 300kg every six months and over 300kg every three months.
Manufacturers of products seeking application-specific information regarding leak testing and functional testing of plastic products can access an online library of leak-test and functional-test applications at the InterTech Development Co.
Leak testing can be performed with various non-destructive test methods, among them acoustic emission (AE), on both, pressure vessels [1-4] and pipes or pipelines [5].
The ILS 500 is a multi-program workstation for trace gas leak testing. Using the ILS 500, all of the designing of a control interface for a leak test station is taken care of in one package.