| 摘要 |
PURPOSE:To eliminate an erroneous judgement at the next cycle, by purging an airtight chamber in a short period of time when a gas leak was detected. CONSTITUTION:Prior to an inspection of an object 7, helium gas is put into a refrigerant passage. A bell-jar 1 is lowered to allow the object 7 to be put into an airtight chamber 5, and a valve 20 of a rough exhausting system 13 is opened to conduct a rough exhaustion up to a prescribed pressure. And then, a valve 21 of a pretest exhausting system 15 is opened, a vacuum exhaustion valve 25 is opened in such a manner as to maintain the pressure, and the exhausted gas is led to a pretesting helium gas detector 24 for execution of a pretest. When a coarse gas leak was detected in the process of the pretest, the bell-jar 1 is raised to discharge the gas to the atmosphere. And, immediately after that, compressed gaseous body is jetted from a gaseous body jetting nozzle 28 into the bell-jar 1 to blow residual gas away from the inside. |
