FDA Metal Detection Standards / Food and drug metal detector / food metal detection system

HOW A METAL DETECTOR WORKS

The most widely-used type of metal detector in the food industry functions on the principle known
as the "balanced coil" system. This was first registered as a patent in the 19th century, but the
first industrial metal detector was not produced in the UK until 1948.
The progress of technology has taken metal detectors from valves to transistors, to integrated
circuits and more recently, into microprocessors. Naturally this has increased their performance
giving greater sensitivity, stability and flexibility, as well as widening the range of output signals and
information they provide.
All the same, modern metal detectors are still unable to detect every particle of metal passing
through them. The physical laws applied in the technology limit the absolute capability of the instrument. Consequently, as with any measuring instrument, metal detectors have restrictions on accuracy. These restrictions vary depending on the application, but the main criterion is the size of the detectable metal particle. Despite this, though,metal detectors perform a valuable and essential role in process quality control. Two Main Categories for General and Foil-Wrapped Products In the main, modern metal detectors fall into two main categories. The first consists of systems
with a general purpose search head. These are capable of detecting ferrous and non-ferrous
metals as well as stainless steels, in fresh and frozen products - either unwrapped or wrapped,
even in metallised films. The other main category consists of systems which have a ferrous-in foil
search head. These are capable of detecting ferrous metals only within fresh or frozen products
which are packed in a foil wrapping. The "Balanced Coil" System:

How it Works

All general purpose metal detectors work essentially in the same way, although for optimum performance
you should select a metal detector which has been designed specifically for your application.Construction t echniques ensure that independent mechanicalmovement of the search head's
components, and the ingress of water and dirt, are prevented. "For optimum performance you
should select a metal detector which has been designed specifically for your application"
As you will see in diagram 1, the typical detector is encased in a metal box. This houses the coil
components, and provides a shield to protect them. The aperture - the tunnel through which the
A Guide to Metal Detection products pass - is lined with a non-metallic material (usually plastic), which provides an hygienic environmental seal for the internaomponents.The ratio of the aperture size to the size of the product is important, to achieve optimum performance. The sensitivity of the detector is measured at the geometric centre of the aperture, which is the least sensitive point. This is inversely proportional to the size of the aperture - in particular, to the smaller of the two sides.In all, there are three coils in the system. The transmitter coil generates a field, rather like a radio transmitter. This process,
designed to make a metal particle identifiable, is called "illuminating" the metal particle. The
second and third coils are receivers, connected together to detect the presence of an
"illuminated" metal particle. The response is related to theThe realiy detector sensitivity depends on the products and operating environment .

1,Be widely used for medium or small package and bulk food,medicine product lines and so on . For example ,frozen dumplings ,meatballs,aquatic products,sanitary napkin,chafing dish material,prepared food .

2,The machine has learning function of automatic indentification for different detection products , to try its best to reduce the influence of material effect .

3,According to the different products and lines , we can customize different sizes and reject system .l

4,Suitable for wet, dry ,dust ,dew environment , made of stainless steal ,has HACCP attestation , waterproof IP65 .