Method and apparatus for detecting holes in plastic containers
AssigneePlastic Technologies, Inc.
InventorsDonald W. Hayward, David A. Bogstad, Donald Wayne Miller
Life of this patent
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Abstract
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.
Claims14
A method for monitoring the production of blow molded plastic containers for detecting a hole in the container comprising the steps of:
- introducing pressure fluid to the interior of a preform in a mold cavity to form a blow molded plastic container;
- acoustically sensing the sound of pressure fluid travelling through a hole in a wall of the container;
- providing a rigid columnator adjacent the mold cavity to focus and intensify the sound produced by the pressure fluid travelling through the hole in the plastic container;
- and
- producing a control signal in response to the focused and intensified sound from the columnator.
Apparatus for monitoring the production of blow molded plastic containers for detecting a hole in the container comprising:
- a conduit for introducing pressure fluid to the interior of preforms in mold cavities to form blow molded plastic containers during the production of the containers;
- a sensor for sensing the sound of pressure fluid travelling through a hole in one of the containers and for producing a control signal in response to the sound;
- a columnator included in said sensor for focusing and intensifying the sound, said columnator being formed as a rigid tube having an open end adjacent the mold cavity containing the one container;
- and
- a container rejecter for receiving the control signal produced by said sensor for rejecting the one container having the hole therein.
A method for monitoring the production of blow molded plastic containers for detecting a hole in the container comprising the steps of:
- introducing pressure fluid to the interior of heated preforms in mold cavities to form blow molded plastic containers during the production of the containers;
- providing a rigid columnator and positioning a distal end of the columnator adjacent a path of travel of the mold cavities during said introducing of fluid pressure;
- acoustically sensing the sound of pressure fluid travelling through an incomplete finish of a one of the containers with the columnator;
- and
- producing a control signal in response to the focused and intensified sound from the columnator for rejecting the one container.
Dependencies are inferred from the claim text.