Patent ID: 7805259

Claim:
A method for detecting an operation malfunction of a leakage inspector that checks whether a device has a leak, wherein the method comprises: a calibration process comprising: applying pressure to an inside of a first device serving as a reference device; sealing air inside the first device; measuring a pressure change B 1 inside the first device, caused between an end point of sealing the air inside the first device and a first point that is elapsed a predetermined period of time from the end point, and of storing the pressure change B 1 in a storage section; and measuring a pressure change B 2 inside the first device, caused between the first point and a second point that is further elapsed the predetermined period of time from the first point, and of storing the pressure change B 2 in the storage section; and an inspection process comprising: applying pressure to an inside of a second device to be checked for a leak; sealing air inside the second device; measuring a pressure change B 1 ′ inside the second device, caused between an end point of sealing the air inside the second device and a third point that is elapsed the predetermined period of time from the end point, and of storing the pressure change B 1 ′ in the storage section; measuring a pressure change B 2 ′ inside the second device, caused between the third point and a fourth point that is further elapsed the predetermined period of time from the third point, and of storing the pressure change B 2 ′ in the storage section; calculating a value K as (B 1 ′−B 2 ′)/(B 1 −B 2 ); and signaling in response to the value K whether the operation malfunction is detected.