OBSERVER^TM
Second Generation of the Innovative Detector of Metal Contaminants in Aluminum Product Packages

Conventional metal detectors that are used in quality control in industry produce an electromagnetic alternating field. Any metal contaminants in the product to be tested deflect the field lines and can be evaluated as an electrical signal and thus be made visible. Diverse disturbances can adversely affect the detection accuracy attainable, however.
The major disturbances are the product effect (changing conductivity due to fluctuations in moisture, salt content and/or in temperature) and the influences of metallized packages, such as aluminum-coated foil. The latter is increasingly being used in the food and pharmaceutical industries as the diffusion-inhibiting properties of this type of packaging considerably extend the product shelf life.
So far, the only method for reliable detection of metal in aluminum packages has been X-ray technology. However, this technology is very expensive and requires elaborate safety measures to ensure protection against radiation.

By contrast, the new Sartorius OBSERVER^TM metal detector dispenses entirely with this controversial and, for the manufacturer, highly expensive technology. Without time-consuming fine adjustment, the OBSERVER^TM delivers optimal
results that are free of the effects of aluminum-coated packages and/or unstable product properties. The unit is equipped with specially developed sensors that operate on the basis of magnetic field measuring technology.
The products to be tested, such as baby food in jars with aluminum lids, are first premagnetized by the OBSERVER^TM on the infeed side of the belt during monitoring. Then the detector’s magnetic field sensor measures the remanent magnetism of any metal particles present. Moreover, the magnetic field sensor unit of the Sartorius OBSERVER^TM detects AISI 304 particles even if shearing or deformation has altered their crystal structure, as is common during a normal production run, and they have become magnetizable as a result. The Sartorius OBSERVER^TM offers all these advantages even at high conveyor belt speeds.

Moreover, the Sartorius OBSERVER^TM is a metal detector that is predestined to monitor composite packages of chips or ready-to-eat meals, aluminum lids on yogurt, and blister packages of tablets. Because aluminum does not have any magnetic properties, it is practically “transparent” for the Sartorius OBSERVER^TM, therefore enabling the actual final product to be tested for the presence of metal contaminants.

The new generation featuring the Sartorius OBSERVER^TM 300 now covers a wider detection range, enabling contaminants to be detected in bulk materials besides in packaged goods. In addition, the Sartorius OBSERVER^TM 300 is fully integratable into the quality assurance system Sartorius ProControl for WindowsÒ for ensuring 100% traceable recording of metal contaminants to comply with the applicable regulations and Directives. This new metal detector not only serves the needs of consumer protection in line with the International Food Standard, but also can indicate early on whether machines are defective, for example, if they release particles, before any real damage occurs. Further applications areas besides testing aluminum-packaged products in the food and pharmaceutical industries include detection of product flow in stainless steel pipes.