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Finding risks where they occur

Blind spots are undesirable when inspecting the quality of food and its packaging. Part 3 of our series regarding the pulsed X-ray technology available exclusively from HEUFT explains how they can be specifically avoided in a wide variety of applications in order to achieve maximum safety during the detection of foreign objects, defects or product incompleteness along food lines.

It is quite easy with beverage bottles: if they are contaminated with glass splinters, metal particles or other solid foreign objects they can almost certainly be found on the base of the container. Gravity pulls them down regardless of whether the bottles, which are transported upright, are still empty or already filled with liquid contents. Therefore a base inspection with careful pulsed X-ray technology, which the modular HEUFT premium systems for an empty bottle examination and full container inspection have to offer, is generally quite sufficient in order to identify them reliably. It is quite different in the case of liquid food, smoothies, baby food or jams: the higher consistency of such preparations can actually prevent them from sinking – dangerous contaminants then "float" freely in the product frequently very close to the fill line. This makes them disappear too easily from the field of vision of an X-ray detection which only covers the base area.

It is good that HEUFT now has a new stand-alone solution available for such products which emits its X-ray pulses from the side thus covering the complete volume of stand-up pouches, squeeze bottles, carton composite packaging or food cans standing on the conveyor belt in a confined space. The upper of the two X-ray flash modules in the extremely compact HEUFT eXaminer II XS can be electrically adjusted in height and precisely aligned for maximum detection accuracy around the sensitive area of the fill line. This increases the reliability of the foreign object detection in the difficult area around the fill line significantly – and also provides initial information about the filling quantity contained which can be further specified by the uncomplicated integration of additional modules for an exact fill level detection. And glass splinters, metal particles, hard plastic fragments or small pieces of bone are detected reliably in all areas of the filled food packaging from the base to the shoulder.

A continuous X-ray inspection

This is highly precise with an unequalled low radiation exposure. However only with full containers which are transported upright and have a simple, flat base. On the other hand it is considerably more difficult to always detect every splinter solely with the X-ray based sidewall inspection in the case of jam or baby food jars with a base dome, base grooves or alignment and press marks, that is embossing, in this area. Therefore, two further precisely adjustable X-ray modules are also integrated in the HEUFT eXaminer II XAC full container inspector which make such objects hidden behind the base curvature or other material structures visible – in conjunction with the HEUFT reflexx² image processing system with learning ability. As a result a complete base inspection without blind spots is ensured even in the case of thickness variations. And the two strobes for the sidewall inspection cover the rest.

A top-down inspection with the compact HEUFT eXaminer II XB can also be sufficient for food jars with a small height and width as well as approximately the same finish and base diameters. A simultaneous X-ray examination of two containers positioned next to each other at once is even possible in such cases so that the maximum possible throughput can be increased to an impressive 2,400 products per minute. Furthermore the system checks final products in thermoform packaging, pouches, flow packs or boxes for absence of contamination, completeness and integrity. Products with missing or defective product and packaging components are also identified in addition to solid foreign objects. The smart multiple flash option makes the continuous examination of particularly long products and packaging material possible. And there will soon be a new version of the top-down inspector which will also cover particularly wide full packaging material such as frozen pizza boxes completely during the careful and precise X-ray inspection.

An impressive detection reliability

Special systems for an X-ray based pipeline inspection carry out a reliable foreign object detection even before the packaging process: in this way the HEUFT eXaminer XT also finds minute objects made of glass, metal and other high density materials in an unpackaged liquid or paste-like product mass. This makes it ideal for all those who want to process, fill or supply pre-inspected bulk goods. The optional use of an additional X-ray strobe, the so-called dual beam technology, makes the analysis of two overlapping single images possible in the course of this – and with that a 3D reconfirmation of the examination result from a different perspective. A further development of the system based on the highly automated HEUFT SPECTRUM II platform with further optimised X-ray, image processing and rejection technology will follow shortly for even more safety during the detection and rejection of contaminated jams, sauces or fruit preparations.

All the HEUFT eXaminer II systems achieve unprecedented maximum values regarding resolution and image quality due to the use of new X-ray generators, full-field image converters and high-voltage components. The objects to be detected in the undistorted, pin sharp images can be divided into four contrast categories with the HEUFT reflexx² image processing system: product inhomogeneities and packaging components which absorb the X-ray flashes to a lesser extent are thus clearly differentiated from medium and strongly absorbing contaminants such as bones, ceramic fragments, steel or hard glass – and thus harmless deviations from really critical faults. This keeps the proportion of incorrectly rejected good products at the lowest level. Compared to metal detectors the pulsed X-ray technology from HEUFT stands out because neither the inherent signal of saline or acidic products, the so-called product effect, nor metal packaging components can impair its extraordinary detection performance.

Full food safety

This detection reliability does not only extend to partial areas of the food and packaging material to be examined due to the various possibilities for positioning and aligning the compact X-ray flash modules. A continuous complete inspection which makes foreign objects, defects or incompleteness visible wherever they actually occur is generally possible whenever product safety requires it – be it in the middle of the product, at the fill line or at the bottom of the packaging.