Vacuum formed bags of products such as hot dogs are sealed in a vacuum chamber so as to remove all air which could cause premature spoiling of the product. As air is removed from the bag during the vacuum forming process, the bag shrinks about the product so that the resulting package has a uniform and fixed configuration. All similarly sized packages of the same product obtain a uniform configuration after vacuum packaging. Thus the surfaces of the packages are uniformly contoured. In some instances during a vacuum sealing process, a seal is not properly made or the package incurs a leak which allows air to enter the package. Air entering the package quickly deforms the contours that are created during the vacuum sealing process. Because there is no efficient way to detect whether a seal has been broken or a leak occurs, many products which are vacuum sealed in this manner are packaged by hand to allow an operator to inspect every package. The operator inspection method is insufficient and unreliable at full production speeds.
Camera systems have been used to map the profile of packages with structured lighting but the analysis tools available to a camera system are limited and cannot reliably determine a leaking package. Structured lighting such as a laser line projected at an angle across a package can provide a line indicating the profile of the package which can be captured with a camera. However, the line can be distorted or undetectable as it blends with the colours and reflections of the package being analysed. Camera systems are also delicate and very expensive to implement. In addition, camera systems are not well suited for the harsh, wet, and caustic environment where vacuum packed food products are often located. Adding new undamaged package profiles for new packages or products to a camera system typically requires technical personnel to acquire training images and then modify the vision tools used to create a corresponding new production setup. This new package training process can be timely.
The present invention was developed in order to overcome these and other drawbacks by providing a high speed, reliable and cost effective system and method for determining whether a package has been properly vacuum packed while maintaining a good seal.
Kevin J. Jones (Mechanicsville, Va.), Johannes J. M. de Koning (Glen Allen, Va.), Geoffrey J. Parnell (Moseley, Va.)
Flexicell Inc. (Ashland, Va.)