Leak detection method and leak detection device for sealed container

摘要

PROBLEM TO BE SOLVED: To provide a leak detection method, suitable for examination of leaks for a cartage filed with metallic sodium used for especially a sodium-sulfur battery, which enables continuous and sure detection of leaks in a sealed container with a connecting portion sealed between a container filled with content, and a cap, and to reduce inspection cost. SOLUTION: In this leak detection method for the sealed container 5 formed by sealing the connecting portion 4 between the container 2 filled with the content 1, and the cap 3, after covering the container 2 with the cap 3, the container 2 is previously filled with a nitride gas or an argon gas mixed with a helium gas at a concentration of 1 to 20 vol.%; the connecting portion 4 between the container 2 and the cap 3 is sealed to form the sealed container 5, a detecting head 10 is mounted detachably from the sealed container 5, so as to envelop the connecting portion 4 between the container 2 and the cap 3; and after ensuring airtightness of a space 7 formed by the detecting head 10, the container 2 and the cap 3, including the connecting portion 4 between the container 2 and the cap 3, the leak in the connecting portion 4 between the container 2 and the cap 3 is detected by a leak detector 20.