Method and apparatus for inspecting heat-resistant multilayer containers made of synthetic resin

A method of inspecting a heat-resistant multilayer container made of synthetic resin characterized by projecting light to an upper end portion of a mouth portion and a lower thread portion of the mouth portion of a heat-resistant multilayer container formed by blow forming a parison made of main resin and heat resistant resin, receiving light passing the upper end portion and the lower screw thread portion of the mouth portion, extracting and detecting a light having a specific wavelength, outputting the light as an electrical signal and evaluating the quality of the heat-resistant multilayer container in accordance with the output signal value.

An apparatus for inspecting a heat-resistant multilayer container made of synthetic resin, comprising a lighting device for emitting light, a light projecting device connected to the lighting device for transferring and projecting the light to an upper end portion of a mouth portion of a heat-resistant multilayer container made of synthetic resin, a light receiving device located opposingly to the light projecting device for receiving and transferring the light passing through the upper end portion of the mouth portion of the container, a sensor for extracting and detecting a light transmitted from the light receiving device, and a signal processing circuit means for processing an electrical signal from the sensor to provide an indication of the condition of the heat-resistant multilayer container made of synthetic resin.

An apparatus for inspecting a heat-resistant multilayer container made of synthetic resin, comprising a lighting device for emitting light, a plurality of light projecting devices each connected to the lighting device for transferring and projecting the light to an upper end portion and a lower screw thread portion of a mouth portion of a heat-resistant multilayer container made of synthetic resin, a plurality of light receiving devices located opposingly to the light projecting device for receiving and transferring the light passing through the upper end portion and the lower screw thread portion of the mouth portion of the container, a plurality of sensors for extracting and detecting lights transmitted from the respective light receiving devices, and a plurality of signal processing circuit means for processing electric signals from the respective sensors to provide an indication of the condition of the heat-resistant multilayer container made of synthetic resin.