Method and apparatus for detecting holes in plastic containers

摘要

The invention relates to a method and apparatus for monitoring the production of blow molded plastic containers. It has been discovered that by sonically monitoring the production of a plastic blow molded container, the occurrence of a hole in the wall of the container being formed by a blow molding operation will produce a detectable noise signal. The noise signal is caused by the flow of pressure fluid through the hole. The flow of pressure fluid is caused by the pressure differentiating between the inside and the outside of the container being produced. The noise signal is of an amplitude and frequency readily recognizable from the ambient background noise.