Method and apparatus for inspecting for airtightness failure

An airtightness failure inspection method for inspecting the leakage of a tracer gas from an inspection object in which said tracer gas is sealed under pressure, said method comprising:

• (1) an initial step of establishing a first flow path system for generating a constant flow of gas by a first evacuating pump in a cover, which is formed in such a manner as to surround an inspecting area of said inspection object and which is opened to the atmosphere at one end and is connected to a flow path at the other end thereof, and a second flow path system for generating a constant flow of gas which is independent from said first flow path system and which draws in the atmosphere from an atmosphere inlet port and discharges said atmosphere so drawn in from a second evacuating pump via a detector;
• (2) a pre-inspection step of sealing a tracer gas in said inspection object under pressure and placing said cover over an inspecting area of said inspection object;
• (3) a measuring step of switching a flow path system to a flow path system for introducing a gas including said tracer gas that has leaked from said inspecting area and which is drawn out of said cover by said second evacuating pump into said detector for measuring the amount of said leak from said inspecting area at the time of measuring the amount of a leak;
• and
• (4) a cleaning step of cleaning up flow paths constituting said flow path systems of said gas and instruments including said detector after said measuring is completed.