Foreign Body Detectors

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1 Foreign Body Detectors "Foreign Body Detectors (FBD's) are an integral part of every manufacturing process line. Here we explain why permanent magnetic separation equipment is rapidly moving to the forefront of this critically important area" Foreign Body Detectors There are currently three categories that fall into the above heading, these being X-ray devices, Metal Detectors and Permanent Magnetic Systems. Every food manufacturing company operating under HACCP regulation will have either one or a combination of these pieces of equipment in place. X-ray devices are expensive options compared to detectors and magnets, and have a narrow application field in the food environment. Detectors however have a much broader use in any manufacturing process line. Due to the increase in competition in this area standards have been driven to new levels as suppliers try to remain one step ahead of their competition. Both X-ray and Metal detection equipment are very sensitive to their surrounding environment and can be influenced by a number of internal and external anomalies. Out of all the FBD categories permanent magnetic separation equipment offers more benefits and has a greater scope of application.

2 Magnetic Separators Magnetic separation equipment has been supplied to the Food, Chemical and Pharmaceutical industries since the early 1940's. Many advances have taken place since then, helped by the increasing demands put upon magnetic equipment by new processing techniques and advances in magnetic materials. Even though magnetic separation falls under the FBD title the equipment does not detect foreign bodies, they actually attract and remove contamination continuously from the product being processed without the need to stop the process line. This is especially prevalent when large throughputs of ingredients are required and continuous production of a finished product is critical. Detectors are generally located at the end of the process line to check finished products for contamination, separators however are placed in goods intake points, before and after process machinery and at the end of the process fine. This method of foreign body removal is much more effective as each magnet location only has to remove the contamination generated between itself and the previous magnet. This allows quality personnel to easily and accurately pinpoint the area of concern and investigate the cause of the contamination, this acts as an early warning system and will highlight wear and deterioration in critical machinery which could possibly avert a major machine failure. Magnetic Design Magnetic design and performance has improved in the last 10 years thanks largely to the advances in magnetic materials. Up until the early 90's most magnetic separators were manufactured using Ceramic magnetic materials, this was one of the few widely available and cost effective materials we had to work with. All magnetic separators today incorporate Rare Earth magnetic material, a'150 known as Neodymium Iron Boron. Rare Earth magnets are 6 times more powerful than Ceramic material thus greatly improving contamination extraction rates. This material was available in the late 80's but was 10 times the cost of 'Ceramic magnets which, meant it was not a commercially viable option. Now Rare Earth material is much more widely available and has dropped massively in price it is a prerequisite for any separator being supplied to remove ferrous contamination. Separators are continually evolving with advances in new and higher grades of Rare Earth material, units with magnetic performance exceeding 11,000 gauss are now readily available. It should be noted that any magnetic separator's performance reading and certification should be taken at the magnets attractive face and not on to surface of the base magnet as this is not where the contamination is held when attracted. There are around 20 different designs of magnetic separators currently being supplied into the food industry, ranging from Housed drum magnets for the processing of grain

3 through to heated liquid filter for jam, syrup and chocolate. Units are manufactured using food grade 316 stainless steel and are suitable for air or vacuum assisted lines, other units are capable of withstanding 20 bar operating pressure and temperatures in excess of 3500 C. Regardless of your manufacturing or processing technique there is a magnetic separator available to suit your requirements, further more every unit is incredibly easy to install into existing lines. Contamination Removal Separators that incorporate Rare Earth magnetic material are referred to as 'High Intensity' due to the high levels of magnetic flux they emit. Magnetic performance is measured in Gauss, which is the strength of the magnetic field at the separators attractive face, where the contamination is held. High intensity units are capable of removing not only ferrous contamination but also, stainless steel. Most process lines are constructed from 316 grade stainless steel which in its natural state is non magnetic. When any non magnetic stainless steel is broken from the line such as a blade, valve or line wear the pieces become magnetic and are attracted and removed from the product being processed by the magnet. The magnet will attract and secure the offending pieces of contamination until the unit can be cleaned. This is generally carried out between shift changeovers and line shutdowns. The majority of standard units require operator intervention to inspect and clean them however, a number of auto cleaning units are available which are either controlled by a PLC, main control room or by means of a interface with another piece of machinery, this ensures that periodic cleaning is taking place and all collected contamination logged for future reference should a complaint by a client or consumer is submitted. During recent trials it has been proven that sub micron sized contamination can be successfully removed from processed products. The question is how do you know that you have such minute contamination? Metal detector won't find it! and can't even be used for liquids or syrups etc. The most common and potentially damaging method is that your client has high

4 intensity magnets and they find that the product you have been supplying has contamination. How damaging would that be to your quality and reputation? Primary And Secondary There are two categories that magnetic separators fall into, primary stage for removing 'tramp' items such as nuts, bolts washers etc to protect process machinery and secondary stage which, have been designed to remove both tramp and minute pieces of contamination. When choosing a separator the following criteria must be considered to ensure that the effectiveness of the magnet is the best it can possibly be. Location Product flow characteristics Product throughput Magnet configuration Magnetic performance Accessibility All too often this, simple criteria can be overlooked when considering the type of separator which best suits your requirements, you may be able to argue a case that you have taken all necessary steps to show due diligence if an incident was to occur. Auditors and other independent bodies are quickly learning that magnets must be of the correct specification for their intended use. If you are in any doubt contact a magnetic separation company who will be able to give you the correct information, in fact many manufacturers are willing to carry out free onsite surveys to assess risk and recommend suitable equipment.

5 Limitless Applications Magnetic separators can be utilised in any manufacturing processes whether it is powder, granulate, liquid, syrups or pastes etc" Particular success has been achieved with heated chocolate. New application requirements are continuously advancing separator design. But I Already Have Detectors? For those of you who already have metal detectors at the finished product stage why not consider implementing magnetic separators at the ingredient processing stage to reduce and eliminate the possibility of contamination ever finding its way into a finished product. Not only is this method much more effective it will reduce product wastage as the magnets only removes the contamination and does not eject good product, a common fault with detectors. When the magnet is inline you know it is definitely working. Manually cleaned units do not have any funning or expensive service costs and due to the stability of the magnetic material will last indefinitely if cared for correctly. Summary In an ever changing environment with increased scrutiny being placed on food safety ever conscientious quality, engineering and commercial personnel should, at ever opportunity take all available means to reduce the risk of contamination being introduced into food products. For further information please contact: Peter Tedesco Magfield Manufacturing Pty Ltd 5/4 Ovata Drive Tullamarine Vic 3043 Tel Fax peter@magfield.com.au