Abstract: There is disclosed a method for inspecting leakage of a sealed container which is effectively used for detecting a leaking place such as a pin hole, crack, etc. of a sealed container which contains foods, pharmaceuticals, chemical industrial products, etc. A method for inspecting leakage of a sealed container according to the present invention comprises changing an internal pressure of a vacuum chamber provided with an eddy-current displacement sensor to a predetermined degree of vacuum from a normal pressure after putting a sealed container to be inspected having a conductive material on at least at a portion of the container in the chamber; detecting an amount of expansion of the sealed container at the degree of vacuum in time sequence by the eddy-current displacement sensor; and determining any change in the amount of expansion after a time when the detected amount of expansion shows the maximum value, thereby to determine any pin hole formed in the sealed container.

Abstract: An inverter-type resistance welding machine includes a keyboard for inputting desired welding current command data corresponding to commanded values, a display unit for displaying, in the form of a numerical table or graph, the welding current command pattern data inputted by the keyboard, a memory for storing a plurality of the welding current command patterns set by the keyboard and from which these patterns are read out in response to a selection command from the keyboard to serve as a control command of the inverter, and acceptability decision means which successively accepts detected welding current at the time of welding for making a comparison with the reference welding current command pattern over a full range of values, checking correlation between the detected welding current and the reference welding current command pattern and determining whether the detected welding current lies within a predetermined tolerance.