| 摘要 |
PROBLEM TO BE SOLVED: To provide a differential pressure type leak test method capable of surely and efficiently preventing wrong determination due to internal defect and contributing to improvement of reliability and improvement of productivity. SOLUTION: According to this leak test method, pressurized gas is sealed in a material to be measured and a master, and a differential pressure change amount between both is measured to determine the presence/absence of leakage. When the leak amount L1 obtained in the first measurement (step S3) is larger than leak standard Ln (L1>Ln), in the lapse of fixed time, re-measurement is conducted (step S7). When this time measured leak amount Lk is larger than the leak standard Ln (Lk>Ln), the preceding leak amount and this time leak amount Lk are compared, the cycle of re-measurement is repeated until the difference (Lk-1-LK) is smaller than a preset valueΔLn, that is, until the internal pressure of the material to be measured becomes stable, thereby making final determination on whether no leak (step S9) or leak present (step S11).
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