Leak detection, calibrations and reference flows: Practical example

Calcatelli, Anita; Bergoglio, M.; Mari, D.

doi:10.1016/j.vacuum.2007.04.019

Cited by 36 publications

(26 citation statements)

References 9 publications

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“…Calcaletty [4] makes an analysis of the metrological leak detection method based on the application of mass spectrometry with tracer gas (generally helium).…”

Section: Fig 3 Caulked Assembly Used At Shock Absorbers Systemsmentioning

confidence: 99%

Systemic analysis of the caulking assembly process

Rodean¹,

Beju

Brindasu

2017

MATEC Web Conf.

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Abstract. The present paper highlights the importance of a caulking process which is nowadays less studied in comparison with the growing of its usage in the automotive industry. Due to the fact that the caulking operation is used in domains with high importance such as shock absorbers and brake systems there comes the demand of this paper to detail the parameters which characterize the process, viewed as input data and output data, and the requirements asked for the final product. The paper presents the actual measurement methods used for analysis the performance of the caulking assembly. All this parameters leads to an analysis algorithm of performance established for the caulking process which it is used later in the paper for an experimental research. The study is a basis from which it will be able to go to further researches in order to optimize the following processing.

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“…Calcaletty [4] makes an analysis of the metrological leak detection method based on the application of mass spectrometry with tracer gas (generally helium).…”

Section: Fig 3 Caulked Assembly Used At Shock Absorbers Systemsmentioning

confidence: 99%

Systemic analysis of the caulking assembly process

Rodean¹,

Beju

Brindasu

2017

MATEC Web Conf.

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“…20 showing the behaviour of the scaled conductance in the full range from molecular to viscous though the transition regime depending on the pressure (mean free path) [22,[28][29][30].…”

Section: Calibration Of the Instruments Involved In The Leak Detectionmentioning

confidence: 99%

“…If the leak detector provides the value of the flow-rate it will be necessary to trace the instrument to a primary flow-meter through calibrated leaks, which may be of Fig. 15 Schematic of a leak measurement apparatus [22] the geometrical types, Fig. 17 (hole in a membrane, small capillary tube) or of the permeation type.…”

Section: Calibration Of the Instruments Involved In The Leak Detectionmentioning

confidence: 99%

“…Table 2 lists both mass or volume flow-meter available at I.N.RI.M. [22] and the expanded uncertainty values for the various ranges as listed in the BIPM database [23]. Geometrical leaks: (a) capillary type [13] and (b) holes in membranes [17] Leak Detection: General Remarks and Examples…”

Section: Msld Unitmentioning

confidence: 99%

“…Many leak detectors are automated in order to reduce operator's influence; that has increased enormously the use of those devices in areas not previously considered in many industries, not only in research field. Figure 15 shows an example of application of the MSLD [22], in which a commercial detector is used for approval tests of various components in cryogenic industry (compressors, heat exchangers) as well as in automotive industry (light alloy rims for automobiles or trucks, cylinder heads) for which the threshold value of the leaks must be defined to accept or to reject the considered components. The objects are tested by pressure-vacuum technique with helium as tracer gas.…”

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confidence: 99%

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Leak Detection: General Remarks and Examples

Calcatelli¹

2011

Integrity of Pipelines Transporting Hydrocarbons

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Structure defects may be detected by all the non-destructive analysis techniques from radiography, magnetic particles, liquid penetrating, to ultrasounds, to eddy currents, etc. Nevertheless, to evaluate the quantity of liquid or gas that may be lost in the surrounding ambient specific techniques related to leak detection should be considered. Frequently the maximum acceptable leaks must be evaluated to select the method suitable for the specified object and, finally, to compare the solutions on the basis of costs-benefit relationship. Various leak detection methods and related instrumentation are available (bubbles, ultrasound emission, radar, pressure/vacuum variation, thermal conductivity, halogens, radioisotopes, selective ion pumping, mass spectrometry). Before starting any type of leak testing, it is necessary to decide whether leaks have to be located or measured. Checking the tightness of an object or device implies the measurement of gas flow coming out from a defect or entering through it and reference devices should be provided by primary or accredited laboratories. After a short review of methods/instrumentation attention is given to the calibration of any kind of systems and methods to guarantee the validity of the whole test. General Considerations on LeaksIt is not possible, to date, to have systems or components absolutely tight even if the technology had enormous developments (Fig. 1). Containers always have a leak, be it of gas or liquid from a high-pressure artefact whether entry of fluid in an object kept at low pressure (Fig. 2).And then, some components for the operation of which a degree of tightness has to be guaranteed should be subjected to a control apt to show any leakage due to material defect, faulty workmanship, non hermetic assembly, material degradation The tightness test is a non-destructive test and may be defined as "a test performed to verify compliance of materials or components to specified requirements, using techniques that do not damage the characteristics or working performances".Only in a very lucky situation, so very rarely, a leak is represented by a cylindrical channel, more often it is due to a tortuous small duct or may also occur through a permeation process.The leak usually is not deformable, so it has a constant value unless strong mechanical or thermal stress occurs through the walls of a container located between two environments kept at different pressures (Fig. 3). A real leak causes a change of the pressure in the container and it is through a "hole" on a wall connecting the interior of the container with the atmosphere. Even a virtual leak causes a change in pressure inside the considered volume, but it is caused by the evolution of gas or vapour within the system itself, such as desorption of gas from the material of the container or diffusion within the wall followed by emission inside the chamber.A tightness test implies, therefore, measuring the flow of gas (the amount of gas in time), that escapes from the defect or enters in. Over the years ...

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Methods of Leak Detection

Bley¹

2016

Handbook of Vacuum Technology

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Leak detection, calibrations and reference flows: Practical example

Cited by 36 publications

References 9 publications

Systemic analysis of the caulking assembly process

Systemic analysis of the caulking assembly process

Leak Detection: General Remarks and Examples

Methods of Leak Detection

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