Patent ID: 9453776
Filing Date: 2016-09-27
CPC Classification: G01L,G01M

Claim Text:
1. An internal pressure inspection apparatus for a sealed container having a can lid that is attached to any of an upper end and a lower end of a can trunk, and that is deformed by an internal pressure of the container, comprising: a laser displacement sensor that measures a distance from a plurality of spots on a diametrical line of the can lid in a conveyance direction of the sealed container by irradiating the can lid of the sealed container with the laser beam continuously; and a controller that judges acceptability of the internal pressure of the sealed container based on the distance measured by the laser displacement sensor; wherein the controller is configured to: calculate a relative displacement value of the can lid by calculating a deviation between: a distance between the laser displacement sensor and a predetermined reference point; and each distance between the laser displacement sensor and other points; calculate an integral value of the relative displacement values; determine a fact that the internal pressure of the sealed container is acceptable if the integral value falls within a predetermined acceptable range between an upper limit value and a lower limit value; and determine a fact that the internal pressure of the sealed container is unacceptable if the integral value falls out of the acceptable range.