Method and apparatus for measuring a characteristic of a plastic container

A system for inspecting plastic containers comprising:

• an emitter assembly including a light energy source for directing light energy through at least two sidewalls of each plastic container as the plastic containers successively travel on a transport path past the light energy source;
• a sensor assembly including a sensor for sensing a portion of the light energy that passes through the sidewalls of each plastic container, wherein said emitter assembly is positioned on a first side of the transport path and said sensor assembly is positioned on an opposite side of the transport path such that the plastic containers pass between said emitter assembly and said sensor assembly;
• and
• a computer connected to said sensor assembly and responsive to a signal related to the light energy absorbed by the sidewalls of each plastic container, wherein the signal is generated based on the sensed portion of the light energy that passes through the side walls of each plastic container, and wherein said computer is for determining at least one characteristic for each of the plastic containers based on the signal wherein the at least one determined characteristic includes the average thickness of the sidewalls of the plastic container and the average thickness of the sidewalls is used to determine a second characteristic.

A method for inspecting plastic containers, the method comprising the steps of:

• directing light energy from a source of light through at least two sidewalls of each plastic container as the plastic containers successively travel on a transport path past the source of light energy;
• sensing with a sensor a portion of the light energy that passes through the sidewalls of each plastic container, wherein the source of light energy is on a first side of the transport path and the sensor is on an opposite side of the transport path such that the plastic containers pass between the source and the sensor;
• generating, for each plastic container, a signal from the sensed portion of the light energy that passes through the sidewalls of the plastic container that is related to the light energy absorbed by the sidewalls of the plastic container;
• inputting the signals to a computer;
• determining, by the computer, at least one characteristic for each of the plastic containers based on the signal wherein the at least one determined characteristic includes the average thickness of the sidewalls of the plastic container.