Apparatus and method utilizing signal modulation detection for analyzing the internal pressure of containers

A method for analyzing the internal pressure of containers, said method comprising the steps of:

• inducing vibration in a surface of a closed container by imposing a magnetic field on the surface;
• detecting sound resulting from the vibration;
• deriving original information representing the detected sound;
• testing said original information to determine whether a modulating distortion is present in said original information, and if so compensating for the effects of said modulating distortion, thereby producing demodulated information;
• determining whether a frequency component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined frequency condition, wherein the predetermined frequency condition corresponds to a range of acceptable frequencies, including comparing the information to the range of acceptable frequencies;
• and
• determining whether an amplitude component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined amplitude condition, wherein the predetermined amplitude condition corresponds to a minimum or a maximum amplitude threshold, including comparing the information to the amplitude threshold.

A method of operating a manufacturing line, the method comprising:

• passing closed containers through a container inspection system, and at the container inspection system
• inducing vibration in a surface of each of the closed containers;
• detecting sound resulting from the vibration;
• deriving original information representing the detected sound;
• testing said original information to determine whether a modulating distortion is present in said original information, and if so compensating for the effects of said modulating distortion, thereby producing demodulated information;
• determining whether a frequency component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined spectral frequency condition;
• and
• determining whether an amplitude component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined spectral amplitude condition.

A method of operating a manufacturing line, the method comprising:

• passing closed containers through a container inspection station, and at the container inspection station
• inducing vibration in a surface of each of the closed containers;
• detecting sound resulting from the vibration;
• deriving information representing the detected sound;
• determining whether a frequency component of said information corresponds to a predetermined spectral frequency condition;
• and
• determining whether an amplitude component of said information corresponds to a predetermined spectral amplitude condition by comparing said amplitude component to a range of acceptable values delimited by a lower limit and an upper limit;
• accumulating, from a plurality of containers inspected at the container inspection station and judged to be satisfactory by satisfying said predetermined spectral frequency condition and said predetermined spectral amplitude condition, amplitude data for the amplitude components of said containers;
• analyzing said amplitude data to derive an average value and a deviation therefrom;
• and
• resetting at least one of said lower limit and said upper limit in dependence upon said average value and said deviation.

Apparatus for analyzing the internal pressure of a closed container, the apparatus comprising:

• vibration means for inducing vibration in a surface of the closed container;
• sound detection means for detecting sound resulting from the vibration;
• information derivation means for deriving original information representing the detected sound;
• and
• data processing means arranged to:
• (a) test said original information to determine whether a modulating distortion is present in said original information, and if so to compensate for the effects of said modulating distortion, thereby producing demodulated information;
• (b) determine whether a frequency component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined spectral frequency condition;
• (c) determine whether an amplitude component of (a) said original information, if no modulating distortion has been found therein, or (b) said demodulated information, if modulating distortion has been found in the original information, corresponds to a predetermined spectral amplitude condition;
• and
• (d) produce a first output signal if said frequency component and said amplitude component correspond to said predetermined spectral frequency and amplitude condition respectively, and a second output signal if said frequency component fails to satisfy said predetermined spectral frequency condition or said amplitude component fails to satisfy said predetermined spectral amplitude condition.

A manufacturing line having a container inspection station and transport means for moving closed containers through the container inspection station, the container inspection station comprising:

• vibration means for inducing vibration in a surface of a closed container at the container inspection station;
• and
• sound detection means for detecting sound resulting from the vibration,
• wherein the manufacturing line further comprises:
• information derivation means for deriving information representing the detected sound;
• and
• data processing means arranged to:
• (a) determine whether a frequency component of said information corresponds to a predetermined spectral frequency condition;
• and
• (b) determine whether an amplitude component of said information corresponds to a predetermined spectral amplitude condition by comparing said amplitude component to a range of acceptable values delimited by a lower limit and an upper limit;
• (c) accumulate, from a plurality of containers judged to be satisfactory by satisfying said predetermined spectral frequency condition and said predetermined spectral amplitude condition, amplitude data for the amplitude components of said containers;
• (d) analyze said amplitude data to derive an average value and a deviation therefrom;
• and
• (e) reset at least one of said lower limit and said upper limit in dependence upon said average value and said deviation.