To provide an inspection method, for the airtightness of a composite insulating tube, in which the usage amount of a pressurization gas is reduced, in which the required time to fill the pressurization gas into the composite insulating tube and to collect the gas after an inspection is shortened, in which the airtightness of the bonding part of a core tube to a flange metal fitting can be inspected regarding respective end parts of the composite insulating tube, in which the operability of the inspection is good and in which a high internal pressure is not applied to a pressurization-gas supply jig.
In a method, the airtightness of a bonding part 4 to a flange metal fitting 3 attached and bonded, in a close contact state, to the outer circumference at the end part of a core tube 1 at a composite insulating tube is inspected. At this time, the internal space of the core tube 1 is partitioned, to be an airtight state, into a space on the side of an end part 4a on one side and a space on the side of an end part 4b on the other side by using a partition wall. A pressurization gas is pressurized and supplied 103 to the outer circumference on the side of the end part 4a on one side and at the end part of the core tube 1 and to one end of the bonding part 4 of a housing 2 to the flange metal fitting 3. Whether the pressurization gas is leaked from the end part on the other side of the bonding part 4 or not is detected 104, and the airtightness of the composite insulating tube is inspected.
SOGA MASASHIGE
KIRII MASANOBU
