Measuring and testing – With fluid pressure – Leakage
Patent
1997-11-17
1998-10-27
Brock, Michael
Measuring and testing
With fluid pressure
Leakage
73 3103, 73 407, G01M 304, G01N 700
Patent
active
058279490
DESCRIPTION:
BRIEF SUMMARY
SPECIFICATION
1. Technical Field
The present invention relates to a method and system for measuring external leakage.
2. Background Art
In a gas supply piping system, a vacuum apparatus, etc. in a semiconductor fabrication system etc. requiring high purity gases and a highly-clean atmosphere, an external leakage must be prevented with all efforts. An external leakage arises usually at a connecting portion of parts, and to prevent it, there have been considered welding techniques and joint methods which do not lead to an external leakage. As a result, there has been established a technique in which an external leakage is less than the limit of detection of the present He leak-detector.
However, even if component parts and connecting techniques have been improved, contaminants may be caught between the parts when the system is constructed, or defective parts can not be avoided perfectly. Accordingly, as a matter of fact, an external leakage is inspected after construction of a fabricating process, to confirm security of the process.
As a method of measuring an external leakage, there is one using the above-described He leak-detector. In this method, the inside of piping etc. to be measured should be highly evacuated, and a point to be inspected should be bagged and blown by He gas, which requires a great deal of time and labor. Particularly, the longer the line to be measured is, the greater the required time and labor become. Further, its sensitivity is not so good, which is another drawback.
The present invention provides a method and system for measuring external leakage, which can obviate the above-described problems of the conventional method of measuring an external leakage, can measure simply, and have good sensitivity.
DISCLOSURE OF THE INVENTION
Briefly speaking, to obviate the above-described problems, a method of measuring an external leakage, according to a first gist of the present invention, comprises the steps of: introducing a first gas different from main component gases of an external atmosphere around the portion where the external leakage should be measured into the inside of that portion; adding H.sub.2 gas (or an H.sub.2 containing gas) to the first gas at a point downstream from that portion; and measuring gas components entering from the external atmosphere around said portion where the external leakage should be measured, by an atmospheric pressure ionization mass spectrometer at a point downstream from the H.sub.2 gas adding point.
According to a second gist of the invention, a method of measuring an external leakage in a gas supply piping line having a plurality of branch piping lines comprises steps of: introducing H.sub.2 gas (or a H.sub.2 -containing gas) into at least one of the branch piping lines; introducing a first gas different from main component gases of an external atmosphere into the rest of the branch piping lines; and measuring gas components entering from the external atmosphere by an atmospheric pressure ionization mass spectrometer at a point downstream from the branch portion.
According to the third gist of the invention, a method of measuring an external leakage comprises steps of: letting the inside of a portion where the external leakage should be measured be under lower pressure relatively to an external atmosphere; introducing, then, a first gas different from main component gases of the external atmosphere into the inside from a point downstream or upstream from the above-mentioned portion up to given pressure; and introducing the above-mentioned first gas to an atmospheric pressure ionization mass spectrometer to measure gas components entering from the external atmosphere at said portion where the external leakage should be measured, by the atmospheric pressure ionization mass spectrometer.
According to fourth gist of the invention, a system for measuring an external leakage comprises: a gas supply source for introducing a first gas into the inside of a portion where the external leakage should be measured; an H.sub.2 gas adding source for adding H.su
REFERENCES:
patent: 5485016 (1996-01-01), Irie et al.
Kanno Yohichi
Ohki Atsushi
Ohmi Tadihiro
Brock Michael
Knuth Randall J.
Osaka Sanso Kogyo Ltd.
Politzer Jay L.
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