Contaminations with glass, ceramics, stones, and similar materials also constitute a serious problem. X-ray detection systems for food are therefore used for such applications. Sesotec RAYCON systems furthermore offer additional advantages compared to conventional metal detectors (and other X-ray systems available on the market). For example, RAYCON allows the parallel inspection of two different products. Incorrectly placed or overlapping products also are no problem at all. And apart from contaminations, other product defects such as missing product components also can be detected.
The X-rays for "radiographing" are generated by an electric X-ray tube.
A line-shaped detector that measures the arriving radiation is
positioned above the conveyor belt (see picture on the right). X-rays
have a very high energy and are thus able to penetrate solid bodies.
Depending on the density of the inspected object the X-rays, when
passing through the product, are attenuated to a higher (high density)
or lower (low density) degree. The detector converts the remaining
radiation into an electrical signal, and differences in the density of
the inspected object can thus be represented in an image. The higher the
density of a material, the darker
its representation on the X-ray image, and vice versa. The image
processing software detects the contrast differences in the image,
highlights the contaminants or the missing products, and outputs a
Some examples of radiographs taken of inspected food products:
Basically X-ray systems can detect any contaminants whose density
essentially differs from the density of the product to be inspected.
Usually this applies to metals such as steel and stainless steel, but
also to glass, sandstone, quartz, shale, and many others. Sesotec RAYCON
systems also detect contaminants that contain higher-value elements
such as PVC, PTFE, raw bones, and salt lumps. Another special feature of
X-ray systems is that apart from contaminations they also are able to
detect other product defects. Missing products in packings, unwanted air
bubbles, overweight or underweight, broken products, shape deviations,
and even incorrect positions of individual components can be detected to
some extent. This not only guarantees product purity, but also further
improves the quality of the end product.
Application examples for Sesotec RAYCON systems:
However, even X-ray technology is not able to detect all types of contaminants. For example, it is not possible to detect thin foils, insects or molluscs, hair, wood, fibres, textiles, and plastics consisting only of hydrocarbons (PP, PA, PC, etc.).
X-rays are classified as ionising radiation, which in case of improper
use may be dangerous for persons and for their surroundings. The risk
potential, however, depends on the energy and on the dosage of
radiation. Since the production and processing of food of course is a
highly sensitive field, the European Union has passed a specific
directive 1999/2+3EG concerning the use of inspection systems on X-ray
basis to guarantee 100 % safety of the inspected products:
"Food may be inspected with X-rays if the absorbed dose [...] with a maximum radiation energy of 10 MeV does not exceed 0.5 Gy."
Sesotec RAYCON X-ray systems have been designed to operate far below these permitted statutory limits.
The maximum permissible X-ray voltage for the inspection of food is 10 MeV (mega electron volt)=10,000 keV (kilo electron volt)
Sesotec RAYCON systems operate with max. 80 keV (125 times less than permitted)
With additional safety aspects we furthermore guarantee the absolutely safe use of our X-ray systems in the inspection of products in the food sector:
For operators of X-ray systems it furthermore is important that the
maximum permissible X-radiation outside the system is 0.5 μSv/h.
Sesotec RAYCON systems here cause radiation values of less than 0.2 μSv/h.
The operation of Sesotec systems therefore is absolutely safe.