| 摘要 |
PURPOSE:To conduct an accurate leak test by blowing gaseous nitrogen for sealing to the joined part of a body to be tested locally and forming a gas film, and preventing a gaseous helium layer for detection from leaking to an atmosphere. CONSTITUTION:The inside 2 of a vacuum container 1 is evacuated by an exhauster 9, and when a specific vacuum degree is reached, a probe 4 is put close to the joined part 3 of the vacuum container 1 to blow the gaseous nitrogen 5A to nearby the joined part 3, thereby forming the gaseous nitrogen layer 5B. The probe 4 performs the evacuation from an exhaust port 7 and recovers the gas of the gas layer 5B so that it is scattered after striking on periphery of the joined part 3. This state is held for several seconds and then the inside surrounded with the gas layer 5B in the space of the joined part 3 and probe 4 becomes a vacuum space 11. Then the gaseous helium 6A is blown to the joined part 3 to form the gaseous helium layer 6B. The mixed gas 8 of the gaseous helium 6A after striking on the joined part 3 and part of the gaseous nitrogen 5A is recovered through the exhaust port 7. The gaseous helium 6A leaking from the joined part 3 to the inside 2 of the container is measured by a helium leak detector 10. |
