Detecting foreign matter

“We wanted to separate wood and stock from good (sunflower seed),” says one West Coast seed processor. “Some of the colors overlap, so the distinction is difficult.”

In April, Key Technology introduced a new fluorescence-sensing sorter in its Optyx Raptor line, called FluoRaptor. It incorporates what it has called “the most powerful laser in the food industry” to improve high-speed detection and removal of defective product, extraneous vegetable matter (EVM) and foreign material based on varying chlorophyll levels, coupled with color, size and shape variables.

The seed processor is incorporating the FluoRaptor into its processing lines. Today it is able to effect rapid and efficient sorting. His line is equipped with both camera and fluorescent laser sensing systems. “We can put multiple sensors into the sorter for a more comprehensive solution.”

The FluoRaptor can be used with a wide variety of vegetable products including peas, corn, carrots, potatoes, and spinach and other tender leaf products. It can be used to remove lettuce and cabbage core as well as insects, animal parts, cardboard, plastic, metal and glass.

A mix of sorters may include two or more cameras and a laser positioned for different view of the product. “You can find a lot of flexibility in how we configure our equipment to applications,” says Bret Larreau, product manager-sorters for Key.

The user interface displays an image of the food product as the laser illuminates them. Operators can adjust “reject” levels so product falls within prescribed quality parameters.

The more powerful laser system makes differentiating objects with and without chlorophyll much easier. The power density of the FluoRaptor laser improves the signal-to-noise ratio, thus providing a more accurate image, or “product signature,” to enhance detection capability of even very small defects.

The laser is protected by the only Class 1 laser enclosure in the industry, the company claims. “The great thing about a laser is you get a lot higher intensity than you do with a black light tube,” says Larreau.
One of the advantages of the system is quick changeover.  Larreau notes that camera-only fluorescence-sensing sorters require changing mechanical parts. Changeover may take several hours. The FluoRaptor, however, can be changed in seconds with simple product setting procedures.

While the laser system is state-of-the-art, it does not need to displace other devices, including mechanical systems to sift out foreign matter before it gets near the packaging systems.

“People forget about mechanical systems, and they shouldn’t,” says Larreau. “We use vibratory sorters before product even reaches the detection devices. A small piece of wire or glass run across a bar grader will let small pieces of foreign matter fall through. Foreign particle removal is a system solution, not just a piece of equipment.”

Key’s Optyx system offers high-performance connectivity standards including Camera Link, FireWire and Ethernet.