Metal Contaminated Sugar Alert

Latest Metal Contamination Food Safety Alert

On the 28th July 2018, the UK Food Standards Agency released a food alert announcing ‘Tereos UK recalls Granulated Sugar due to the presence of small metal pieces‘.  This is the third report of metal being found in food reaching the consumer in 2018 after six metal contamination alerts in 2017.

Metal In Sugar

Metal enters the food manufacturing process via many different avenues.  Metal can be present in ingredients being delivered to a food processing plant and unless removed at source can enter the process and cause significant damage.  Equipment failure and wear can also lead to metal contamination and is usually removed with the right combination of magnetic separators and metal detectors.

The source of the metal contamination in the granulated sugar is presently unknown and an investigation is most likely underway.  The sugar is sold in the UK by the retailers Iceland, Poundland, and Sainsbury’s and has been recalled.  The metal contamination will be costly in terms of direct financial cost and reputation.

Getting Metal Out of Sugar

Removing metal contamination from granulated sugar is commonly achieved using Drawer Filter Magnets and Plate Magnets.  Plate Magnets are installed in chutes where the sugar flows over the surface.  Due to the small size of the sugar granules Neodymium Rare Earth Plate Magnets are preferable, producing the highest magnetic attractive force to remove small ferrous and magnetically-susceptible work-hardened stainless steel.

SC FF drawer - no tr#14B20B

Due to the potential sticky nature of the sugar, sleeved Drawer Filter Magnets are often preferred, in an easy-clean design.  The Rare Earth Tube Magnet sits tightly inside a fixed stainless steel outer tube.  Cleaning forms part of a daily maintenance schedule, with the Tube Magnets being withdrawn from the sleeves to drag and deposit metal contamination in a discharge chute.

Magnetic Separation Audits

Bunting engineers conduct regular Magnetic Separation Audits at many food manufacturing plants.  An audit involves the visual and physical inspection of every magnetic separator in a plant to check on the location, suitability integrity (ie checking welds and for wear), and magnetic strength (which can deteriorate with excessive heat, weld damage, or if dropped).  In April three Magnetic Audits were conducted and highlighted a number of issues that have since been addressed.

For more information on preventing Metal Contamination Food Safety Scares, or to arrange a free onsite survey and audit of a particular plant or process, please contact the Bunting team on:

Phone:  +44 (0) 1442 875081

Email:  sales@buntingeurope.com

Via the website

Other Food Safety Articles

 

Our 2017 Review

A Look Back at Our News & Blogs from 2017

2017 has been another busy and exciting time for Bunting Magnetics Europe with some great news stories.  In this blog we look back at the past 12 months and review the stories that hit our headlines.

January

bunting_master_magnetsWe started the year by announcing that Bunting had acquired leading UK Magnetic Separator and Metal Detection company Master Magnets.  This changed the Magnetic Separator landscape in Europe.

At the same time, the Bunting team was exhibiting at the Arabplast exhibition in Dubai.  The plastics focused event was attended and visited by plastics professionals across the region.  Sales were even made on the stand!

Our 7th of our 8 Magnetic Separator Myths examined the impossibility of achieving 100% metal separation.

To finish off January, we announced record sales in 2016 despite the backdrop of Brexit and political uncertainty.

February

We started the month with our 8th Magnetic Separator myth, asking if it was possible to block a magnetic field.

Bunting also joined the British Plastics Federation, reflecting our longtime involvement in the sector providing metal separation solutions.

Bunting at Exposolidos 2017

Our exhibition focus in the month was Exposolidos in Spain with our local representative SMED Tecnica.

In February, we also asked the question of whether our Environmental future is simple down to design?  This was written in response to the growing awareness of the environmental impact of waste that would gradually intensify through the year.

We finished off the month with the launch of the Teardrop Tube Magnet, ideal for use in fine powders where bridging might be an issue.

March

The strength of a Magnetic Separator is often expressed in ‘gauss’.  However, the vast majority of people are unable to measure gauss and so we showed a simple practical way to check the magnetic power using a simple spring balance.

Our 9th Magnetic Separator myth highlighted the dangers of strong Magnets and our 10th myth looked at ways to easily and safely clean captured metal off  Magnetic Separators.

We also investigated a US FDA report stating the ‘Ingesting Metal Fragments Can Cause Injury‘.

In March, we exhibited at the Southern Manufacturing and Electronics show in Farnborough UK.

April

Metal is commonly found in spices and we examined a typical plant and identified the best locations for Magnetic Separators and Metal Detectors.

We also reported that we sold a record number of Plate Magnets in 2016 for export to Indonesia and 28 In-Line Magnets to a German baby food producer.

New Bunting Sales EmployeesWith the continued growth of the business, we were thrilled to announce the appointment of two new sales engineers, Tom Higginbottom and Gordon Kerr.

In April, UK supermarket Morrisons was hit by a metal-in-food scare and we looked at how this could have happened and ways in which such a problem could have been prevented.

May

Our Food Safety theme continued in May when, during a metal separation survey, we found large amounts of metal safely captured when processing rice.  Our Perfect Plant review assessed the best methods and equipment location to ensure that metal is removed from Processed Vegetables.

Exports continued to proved successful with the shipment of a HFS Drawer Magnet to a Plastics recycling company in France.

Our technical review in May reviewed the effect of high temperatures on Rare Earth Magnetic Separators.

June

There was a political flavour to news in June after the UK’s general election and we investigated what the leading parties were promising with regards to the environment.  At the same time, Bunting and Master Magnets were jointly exhibiting at Waste 17, a major UK recycling show in Manchester.

The week after, Bunting supported local representative BMS France at the FIP Solution Plastique exhibition in Lyon, France.

To mark the UK’s Food Safety Week, we reviewed recent cases of ‘metal’-in-food’ and the potential implications for the manufacturer, sales outlet, and customer.

July

Denis_Elkins_Bunting_Magnetics_Europe-2176In July, we were thrilled to announce the successful transition to ISO9001 2015 Quality and the ISO14001 2015 Environmental Standards.

In the media there was increasing attention on the issue of plastic waste in the environment and we commented on the necessity of a global strategy for Plastic Waste.

August

The environmental theme continued in August asking if the UK could realistically increase their metal packaging recycling rate by 10% by 2020.

September

As a prelude to RWM17, the UK’s largest waste and recycling show, we looked at 3 UK Waste and Recycling Facts such as asking how much waste do we actually generate?

Bunting Master Magnets at RWM17

After exhibiting at RWM, there were many questions being asked by exhibitors and visitors about the future of the event despite the importance of recycling and the global waste problem.

October

Bunting Magnetics Europe at Interplas 2017

The UK’s leading plastics show, Interplas, is held every 3 years and, as in previous years, it was very well supported by both exhibitors and visitors.  The environmental issues associated with plastic waste was gathering momentum.

Removing metal from fine powders can be extremely difficult and we produced a technical report looking at the best techniques and ideal equipment.

Tom Higginbottom attended the successful Bulk Solids & Powders show SyMas in Poland with the local Bunting representative TEKPRO.

November

The Manufacturing and Engineering industries have been concerned about the lack of young engineers and hopefully initiatives such as Tomorrow’s Engineers Week will help address this issue.

We were also excited to report two consecutive record sales months in September and October.  2017 was proving to be as successful as 2016.

Our latest Perfect Plant review focused on the brewing of beer and ensuring that all metal is removed to protect delicate processing equipment and the taste of the beer.

December

Pantomine BlogThe BBC TV series Blue Planet had highlighted the global problem of plastic waste in our oceans.  However, as the pressure increased on the plastics sector, we asked whether Plastic was the Pantomime Villain of the recycling world?

We hope you have enjoyed reading our news and blogs in 2017.  If there are any topics that you would like reviewed, then please get in touch and send an email to Paul our press officer (press@buntingeurope.com).

For further information on Magnetic Separators or Metal Detectors please contact the Bunting team on:

Getting Metal Out of Beer

Ideal Locations for Magnetic Separators and Metal Detectors in a Brewery

Thankfully, it is very unlikely that you will ever find a piece of metal in your glass of beer.  However, when tramp metal in the form of screws and nails is accidentally introduced during the brewing process, it damages processing equipment and can even affect the taste of the beer.  In this article we look at the best methods of ensuring that the brewing process is unaffected by tramp metal.

Bunting_Magnetics_Europe_Brewery_Plant

As with any food process, there are many locations where metal can be inadvertently introduced.  With raw materials being collected from the fields and then transported to the brewery in large trucks, contamination by metal and other materials is unavoidable.

Here we look at a typical brewery and identify where Magnetic Separators and Metal Detectors could be located to remove any metal contamination.

Location 1 – Malt In-feed Line

When the malt is delivered by truck or rail, it is commonly pneumatically transported into storage silos.  A Pneumatic In-Line Magnet and/or Metal Detector would ensure that any tramp metal in the raw material feed is removed prior to storage.

Bunting Magnetics In Line Magnet-2

A Pneumatic In-Line Magnet is designed to easily fit into a pipeline without causing any obstruction.  It has a magnetically strong Plate Magnet mounted on one side which attracts and holds any ferrous metal.  This is then manually removed on a regular frequency.

The Metal Detector identifies and then ejects any remaining metal contamination, both ferrous and non-ferrous.  As most metal contamination at this stage is ferrous, installing the Metal Detector after the In-Line Magnet reduces the amount of metal detection rejects and thus reduces the loss of product.

Location 2 – Prior to Milling

cartridge_magnetsGrate Magnets are commonly positioned in or above the in-feed hopper to the mill, especially if there has been no previous metal separation or detection.  A Grate Magnet is a series of Tube Magnets designed in a grid to fit inside a hopper.  For maximum protection of the mill, the Grate Magnet uses a set of high magnetic strength Rare Earth Neodymium Tube Magnets.  Such protection ensures that no tramp metal enters the mill where it can cause serious and expensive damage.

Location 3 – Hot Water Feed to Mash Tun

Bunting Magnetic Liquid TrapWater is a common source of metal contamination in food processing plants and is also the one in-feed material that is often overlooked.  The nature of water means that rust is common and a simple Magnetic Liquid Trap is used to attract and capture any rogue ferrous metal, even in a very fine form.  A Magnetic Liquid Trap is designed to be easily introduced into a pipeline, with flanges or any other connector.  Inside the body, high strength Rare Earth Neodymium Tube Magnets project down into the material flow, attracting and capturing any ferrous or weakly magnetic materials.  The Tube Magnets are removed from the process and manually cleaned.

Location 4 – Between Mash Tun, Lauter Tun and Brew Kettle

Magnetic Liquid Traps could also be located between the Mash Tun, Lauter Tun and Brew Kettle, especially is there has been limited protection earlier in the process.

Location 5 – Hops In-feed Line

Protection is important whenever raw materials are introduced into the process and Grate Magnets and a Quicktron Metal Detector will ensure that hops entering the brew kettle are metal-free.  This design of Metal Detector is for free-fall material.  As the material enters the metal detector, any metal is detected and then automatically rejected.  The Grate Magnet reduces the amount of material lost during the rejection process by removing any ferrous metal.

Location 6 – Between Brew Kettle and Whirlpool/Settling Tank

After the brew kettle , a Magnetic Liquid Trap, with special Neodymium magnets designed to withstand high temperatures, will provide final protection prior to settling.

Location 7 – Yeast In-feed Line

As on the hops in-feed line, a combination of a Grate Magnet and Quicktron Metal Detector will ensure that any metal does not enter the process.

Location 8 – Between Conditioning Tank and Filter

To protect the filter, a Magnetic Liquid Trap is often installed after the conditioning tank.

Location 9 – Prior to Bottling

p-TRON-GM-V2As in many food processing plants, it is good practice to install a Metal Detector (in this case a P-Tron) at the final stage of the process.  This provides a final stage of protection to ensure that any metal introduced into the process from damaged processing equipment such as the filter or in the pipes is detected and removed.

This is a typical example of a Brewing Operation.  However, each plant is unique and often a site visit is required to assess and recommend the best ways to ensure a metal-free end product.

For further information on removing Metal during the brewing process using Magnetic Separators and Metal Detectors, please contact the Bunting technical sales team on:

Other Food Plant Reviews include:

Bunting_Magnetics_Europe_Brewery_Plant

 

 

 

The Challenges of Removing Fine Iron from Powders

Magnetic Separators Designed for Processing Powders

Removing metal contamination when the tramp metal and material is granular is far more straightforward than when in a powder form.  To determine the best solution to remove fine iron contamination from powders, it is necessary to have a good understanding of the way the fine materials behave.

Powders are produced and used in a wide variety of industries including food, pharmaceuticals, refractories, and chemicals.  It is estimated that 80% of materials used in industry are in a powdered form.

flour-791840_960_720A ‘powder’ is defined as fine dry particles produced by the grinding, crushing, or disintegration of a solid substance.  The nature of a powder means that the handling and processing tends to be problematic as powders exhibit similar properties to both solids and liquids.

Metal contamination, commonly in an iron form, can be introduced into a material at any stage within a process.  Tramp metal that is undetected and remains in the product before the powder production stage, becomes significantly reduced in size and, subsequently, increasingly difficult to extract.

Magnetically susceptible metal contamination (i.e. iron) is commonly removed using Magnetic Separation Equipment, which traps metal using Ceramic Ferrite or Rare Earth Neodymium Iron Boron (Neodymium) Magnets.  Although there are Magnetic Separators where the magnetic field is produced via an electrical current, the vast majority utilize permanent magnets such as Ceramic Ferrite and Rare Earth Neodymium Iron Boron (Neodymium).  Ceramic Ferrite Magnets produce low strength but deep magnetic fields, while Neodymium Magnets create the strongest permanent magnetic presently commercially available.

Where Does The Metal Originate?

Metal contamination commonly originates in a powder from two sources:

  1. Primary large tramp metal, such as a nail, screw or bolt;Tube Cartridge Magnets Bunting Magnetics-5
  2. Primary or Secondary fine tramp iron. Primary fine iron or magnetic particles are often present in the raw material.  This originates from primary processing, transportation, or even naturally occurs in the original material.  Secondary fine iron originates from a larger tramp metal source that has been reduced in size during the process.  Typically, this could be from a nail, screw or bolt that has been through a size reduction process, or from damaged or worn processing equipment.  Another common source of secondary fine iron contamination is rust, falling into the process from weathered and worn processing equipment such as chains, hoists, and building cladding.

The separation and detection of tramp metal is easier when the metal contamination is in a larger form and can be successfully removed using a wide range of suitable Magnetic Separators and Metal Detectors.  Magnetic Separators using standard strength Ceramic magnets, with deep magnetic fields, are ideal.  A good example is the Plate Magnet, often installed in a chute, in a housing, or as part of an In-Line Magnetic Separator.

Quicktron05A_Sodium Bicarbonate 2

Larger metal contamination is also easier to detect on a Metal Detector.  Metal is detected as it passes through the coil of the Metal Detector and an automatic reject system removes it from the flow.  For detection, the magnetic field generated by the Metal Detector has to see a state change.  Finer sized metal produces a lesser state change and thus increases the difficulty in detection.

In a project in Pakistan, a processor of fine Sodium Bicarbonate is using a Quicktron Metal Detector to remove the larger tramp metal.

Removing larger tramp metal with a Magnetic Separator and Metal Detector prior to the processing stage not only prevents the metal from being reduced in size (e.g. converted into a secondary source of fine iron contamination), but also protects delicate processing equipment such as granulators, shredders, and mills from being damaged by the metal.

Once in a powder form, there are processing parameters to consider when assessing the optimum method to remove fine iron contamination.

How Does a Powder Flow?

When a powder is sprinkled, it remains light and free.  However, when the same powder is vibrated or compressed, it may become very dense and even lose the ability to flow.

Individual grains in a powder cling to each other in clumps, in accordance with the Van der Waals force.  This coagulation often results in the fine iron being trapped in among clean product.  The ability of any Magnetic Separator to attract, hold and separate the fine iron is dependent on the iron being as close to the magnetic field as is physically possible.  If the fine iron contacts the surface of a Magnetic Separator with a high strength magnetic field, it will be held.  However, when the fine iron is held inside a coagulation of powder, then it could be held out of the reach of the maximum magnetic force.  Thus, it will not be separated.

The way a powder flows impacts on the design of the Magnetic Separator.  Powders flowing in a hopper may experience classic flow problems such as ratholing, bridging or flooding, all of which could be exacerbated by the design of Magnetic Separator.

Different Designs of Magnetic Separator

Plate Magnets Bunting Magnetics-9797High strength magnetic fields, as produced by Neodymium, are needed to capture fine iron metal contamination.  There are four main magnet configurations suitable for handling powders.

  1. Tube Magnets (also known as Rod Magnets and Cartridge Magnets), often in a multi-rod Grate configuration;
  2. Flat-faced Magnetic Plates;
  3. Cone-shaped Magnets;
  4. Magnetic Drums with a curved magnetic arc;

Although occasionally a Tube Magnet may be used on its own, it is more commonly part of a larger multi-cartridge Grate system.  The Magnetic Grate is designed to fit inside a hopper, or can be supplied complete with a housing (i.e. as a Drawer Filter Magnet).ff-neo-4

In operation, powder falls freely onto the surface of the Tube Magnet where fine iron strikes the surface and is held by the strong magnetic field.  To ensure that the powder makes contact with the Cartridge surface, deflectors are often deployed above the gaps between the Cartridges.

Powder build-up on the surface of a Magnetic Cartridge will reduce the separation efficiency.  Also, in severe cases, a slight build up on the surface of the Cartridge may quickly cause a blockage of the whole housing.

Such blockages can be prevented by ensuring that there is optimum space between the Magnetic Cartridges.  Also, in some cases, the mounting of an external vibrating motor on the side of the hopper or housing will provide enough disturbance to prevent any material coagulation.  The frequency of the vibration needs careful consideration as it could affect the flow ability of the powder.  Additionally, when vibrators are used, the Magnetic Cartridges need to be manufactured to withstand prolonged periods of vibration.

Bunting Teardrop Tube Magnet

‘Teardrop’ shaped Tube Magnets are specifically designed to stop the build-up of fine powder on the surface.  The sharp edge of the teardrop faces up into the product flow and allows material to flow around the edge and into the magnetic field.  Magnetic particles are captured and held underneath the Tube Magnet.

Flat-faced Magnetic Plates are ideal when it is possible for the material to flow over the surface.  For fine iron removal, the Magnetic Plates would use high strength Neodymium Magnets.  This magnetic field is further enhanced when a Tapered Step is added to the face of the magnet.  Captured iron migrates behind the step and away from the material flow, reducing the risk of re-entering the cleansed product.

As well as being fitted into chutes, Magnetic Plates are incorporated into housings.  The Plate Housing Magnets resist bridging and choking to remove tramp iron and ferrous fines from flow-resistant bulk materials.  The stainless steel housings mount easily to enclosed spouting or directly on processing equipment.

There are optional square, rectangular, and round adapters for easy connection to existing chute work.  A baffle at the top of the housing helps break up clumps and directs product flow over the unit’s two powerful Plate Magnets.

Bunting Magnetics In Line Magnet

Plate Magnets are also used in In-Line Magnets and there are two designs:

  1. Gravity In-Line Magnets (GIM) – The Plate Magnets are positioned in round, sloping spouting where material is under gravity flow.  For effective tramp metal capture, the spouting should be angled no more than 60° from horizontal;
  2. Pneumatic In-Line Magnets (PIM) – These designs are for use in dilute phase pneumatic conveying systems (up to 15psi). They can be installed easily with optional factory-supplied compression couplings and work best in horizontal runs with the plate magnet down to take advantage of material stratification;

Another design of In-Line Magnet is the Center-Flow, although the magnetic field is generated in a Cone configuration instead of a Plate.  The Magnetic Cone is positioned in the center of the housing, allowing the powder to flow in the space left between the housing.  Center-Flow In-Line Magnetic Separators are commonly used in dilute-phase pneumatic conveying lines up to 15psi.

To achieve optimum contact with the product flow, a conical magnet is suspended in the center-line of the housing.  This tapered, exposed-pole cartridge has a stainless steel “nose cone” to direct the flow of materials around the magnet.  The tapered poles of the cone magnet allow ferrous fines to collect out of the direct air stream.  Additionally, the trailing end of the magnet is an active magnetic pole and holds any tramp metal that is swept down the cone.

Both types of In-Line Magnet are designed with clamps and doors to enable easy access for cleaning.

drumIn specific applications, a high strength Neodymium Drum Magnet will enable the best level of separation.  The Drum Magnet is gravity-fed, usually via a Vibratory Feeder.  The Drum Magnet has a stationary high-strength magnetic arc positioned inside a rotating outer shell.  When material flows onto the drum magnet, the magnetic field projected by the stationary magnetic assembly inside the shell captures fine iron and holds it securely to the drum’s stainless steel surface.  With contaminants removed, the good product falls freely to a discharge point.  As the drum rotates, the captured fine iron travels along the drum surface and out of the magnetic field, where it is discharged.

There are various magnetic field configurations possible, but the most suitable for removing iron from powder is one that produces a Radial Magnetic Field.  This ensures that once captured, the fine iron does not leave the Drum surface until it moves out of the magnetic field.

Processing powder on a Drum Magnet presents more difficulties that other designs of Magnetic Separators.  Firstly, it is recommended that the Vibratory Feeder has an air bed to produce a consistent feed of powder.  Standard Vibratory Feeders may deliver powder in clumps, significantly affecting the separation performance.

Secondly, the shell of the Drum Magnet should be rotated at high speeds.  This will result in some of the powder pluming, and this can be minimized by keeping the distance between the end of the Vibratory Feeder Tray and the rotating surface of the Drum Magnet to a minimum.

The high rotation speed of the Drum Magnet significantly reduces the amount of product lost to the magnetics.  This is because there is less material on the surface of the Drum at any one time, reducing the chance of entrapment.

The use of Drum Magnets operating at high rotational speeds has been very successful in removing fine iron from abrasives, refractories, and other applications where the material has a high specific gravity.

Ensuring Powder is Metal-Free

As the demand for finer and purer powders increases, so does the need to remove even the finest iron.  Understanding the properties and behavior of the powder is vitally important when considering the optimum method of fine iron separation.  Often the ultimate solution is a series of Magnetic Separators and Metal Detectors located at strategic points within the process.

For further information on removing fine metal contamination from powders with Magnetic Separators and Metal Detectors please contact us on:

Getting Metal Out of Processed Vegetables

Ideal Locations for Magnetic Separators and Metal Detectors in a Vegetable Processing Plant

Processed vegetables are a vital part of the food chain.  Tens of thousands of bags of pre-cut carrots and freshly prepared kale are bought in supermarkets daily.  Frozen vegetables have been very popular since Clarence Birdseye invented the quick freezing method in 1924.  Also,  often-unnoticed processed vegetables are present in many everyday food items such as tinned soup, baby food, sauces, and ready-made meals.

However, processing vegetables takes a great deal of care and attention as the products are often delicate and can be easily damaged.

BUNT-2286 4 8.5x11 plants

As with all processed foods, there is always the risk of metal contamination.  Metal can be introduced at various stages in the process.  The design and positioning of the Magnetic Separator or Metal Detector has to also respect the delicate nature of the product.

Untreated Vegetables Feedstock

During the collection and transportation of the raw vegetables, there is always a high risk of metal contamination.  This can be remove using a Plate Magnet.  To avoid contact with the vegetables and eliminate the risk of damage, the Plate Magnet is suspended above the incline conveyor feeding the washer.  Metal is attracted up onto the face of the Magnet and held until cleaned.  This is ideal to remove larger metal items such as screws and nails.

Post Washing

The vegetables washing process frees dirt and other detritus including metal particles.  Prior to the washed vegetables being fed into a drier, a Permanent Magnetic Pulley, replacing the standard head pulley of a conveyor, attracts and automatically removes any free metal before entering the drier.  Again, there is no physical content between the Magnetic Separator and the vegetables.  After drying, the vegetables are fed into a dicing machine.

Prior to Dicing

Plate Magnet Tapered Step-9545
Plate Magnet Tapered Step

The blades on a dicing machine are delicate and expensive.  Metal contamination can cause significant damage.  To ensure that no metal is present, the dried vegetables are fed over the surface of a Plate Magnet.  This enables higher levels of separation that when the Plate Magnet is suspended as the material is passing closer to the area of maximum magnetic strength.  Any potential damage to the vegetables as they flow over the surface of the Plate Magnet is limited.  Metal is captured and then held under the lip of a tapered step on the surface of the Magnet.

Undersized Vegetables

Smaller sized diced vegetables are often taken on a different route.  They can be mixed with water, for ease of transportation, before being reintroduced into the process.  Immediately after dicing, the smaller particles fall through a Quicktron Metal Detector to remove any small ferrous and non-ferrous metals (including any broken blades from the dicer).  Water from the external source is passed through a Magnetic Liquid Filter Magnet to ensure that any rust or other ferrous metal contamination is not introduced into the process.  The Undersized Vegetables are mixed with the water and then re-introduced into the process.

Final Packed Product

Metron 05C Metal Detector
Metron Metal Detector

The final stage of weighing and packing includes 3 steps of Metal Removal and Detection.  Prior to weighing, the processed vegetables are passed over the surface of a Plate Magnet to ensure that all ferrous metal contamination has been removed.  After weighing, the vegetables fall under gravity through a Quicktron Metal Detector where any non-ferrous metals are removed.  Finally, after packing, the finished packed batch of processed vegetables are passed through a tunnel-type Metron C02 Metal Detector as a final check prior to shipment.

This is a typical example of a Vegetable Processing Plant.  However, each plant is unique and often a site visit is required to assess and recommend the best ways to ensure a metal-free end product.

For further information on removing Metal from Processed Vegetables using Magnetic Separators and Metal Detectors, please contact the Bunting technical sales team on:

Phone: +44 (0) 1442 875081
Fax: +44 (0) 1442 875009
Email: sales@buntingeurope.com
Web: http://www.buntingeurope.com

Other Food Plant Reviews include:

Plate Magnets Remove Metal from Tobacco

Record Export Sales for Plate Magnets

Bunting Magnetic Europe manufactured a record number of Plate Magnets for Export to Indonesian tobacco processing plants in 2016.  Each Plate Magnet is installed to magnetically attract and hold tramp metal and nearly 100 were manufactured.

Plate Magnets are used in tobacco processing to remove metal contamination introduced from collection and transportation of tobacco leaves, or in the process.  The Metal Contamination can be large in the form of a nail or bolt, or as small shards.  Metal can damage delicate processing equipment such as the blades on the tobacco leaf cutter, which can prove to be very costly.

Metal Found in Plastic Recycling Bunting MagneticsPlate Magnets are available in two magnet strengths.  Standard Ferrite or Ceramic Plate Magnets are suitable for larger tramp metal.  However, for removing metal from tobacco, higher strength Rare Earth (Neodymium Iron Boron) Magnets were required.  These produce exceptionally strong magnetic fields and capture very fine magnetic particles.

Although many Plate Magnets are installed in chutes, these models for this tobacco installation were mounted above the conveyors.   Metal contamination is magnetically attracted up off the moving conveyor and onto the face of the Plate Magnet.  The amount of metal captured by the Plate Magnets was substantial.

Each Plate Magnet had a Flat Face and was designed to be Self-Cleaning.  They were also supplied with a mounting kit and removable lever.

The specifications of the Plate Magnets supplied were:

  • 31 Rare Earth (Neodymium Iron Boron) Plate Magnets with 165mm (6.5″) deep magnetic field;
  • 38 Rare Earth (Neodymium Iron Boron) Plate Magnets with 125mm (5″) deep magnetic field;
  • 29 Rare Earth (Neodymium Iron Boron) Plate Magnets with 90mm (3.5″) deep magnetic field;

Bunting Plate Magnets

Plate Magnets are one of many designs of Magnetic Separators used in the process sector.  The type of Magnetic Separator is dependent upon the application and the type of metal contamination.

For further details on Plate Magnets or addressing any Metal Contamination and Separation issue, please contact our technical sales team on:

Other articles on Plate Magnets include:

It Is Easy To Clean A Magnetic Separator

10th of 10 Magnetic Separation Myths

The Magnetic Separator has done its job and captured that potentially damaging item of ferrous metal.  Now it is time to remove the captured metal from the surface of the Magnetic Separator.  It should be easy, shouldn’t it?  However, due to the high magnetic power cleaning metal off a Magnetic Separator is becoming increasing difficult and a health and safety concern.

So, is it possible to make the cleaning process easier?

One of the most used Magnetic Separators is the Cartridge or Tube Magnet.  The diameter of the tube is commonly 1 “ or 25.4mm and the length can vary enormously.  They are used in a wide range of Magnetic Separator designs such as Drawer and Grate Magnets and can be supplied in a range of strengths for different applications such as:Bunting Cartridge Tube Magnetic Separators-6256

  • Ferrite – The lowest strength and good for general tramp iron such as nuts and bolts
  • Rare Earth – The strongest magnet and is ideal for fine ferrous contamination and abraded stainless steel;

As already mentioned, the most common problem for users of high strength, Rare Earth Tube Magnets is cleaning.  The magnetic field is so strong that removing captured metal from the surface of the Tube Magnet can be very difficult and a health and safety risk.  So how can the captured metal be removed?  Here are a few examples, some of which may be a little unorthodox:

  • Use a heavy cloth and push the captured metal along the tube surface to the non-magnetic end where it will then discharge. A heavy cloth is recommended as shards of metal may penetrate the cloth;
  • Use heavy duty gloves and a similar technique to the heavy duty cloth, although using PPE for such applications should be discussed with your Health and Safety Officer;
  • Use putty or a similar substance as the metal on the surface of the Tube Magnet becomes embedded in the putty. You may need to move the putty along the Tube surface from points of high to low magnetic intensity;
  • Fit a rubber sleeve over the Tube Magnet before installing into the process line.  Metal is captured on the outside of the rubber sleeve and when it is rolled off the Tube Magnet, the metal is removed at the same time;Bunting Cartridge Tube Magnetic Separators Putty & Gloves

 

Techniques that are not recommended are:

  • Using high pressure water. This may move metal around the surface of the Tube Magnet from the point where the water is striking the surface to the opposite side, but does not effectively clean the magnet;
  • Using high air pressure, where the same problem as with high pressure water occurs;
  • Using high pressure water and air also poses health and safety risks;
  • Rubbing metal off with an unprotected hand. This can result in injury with metal becoming embedded in the surface of the skin;

Cleaning the Cartridge or Tube Magnet is important as it ensures that optimum separation performance is maintained.  Any cleaning process will need discussion with your Health & Safety Officer and we provide free help and support.  For further details on cleaning or on the range of Magnetic Separators and Metal Detectors supplied by Bunting, please contact our technical sales team on:

Other Magnetic Myths reviewed in this series include:

  1. Should You Always Use the Strongest Magnet?
  2. All Rare Earth Magnets are not the Same;
  3. The Highest Gauss Magnet is not always the Best;
  4. Stainless Steel Isn’t Magnetic, or is it?;
  5. Do Magnets Lose Strength Over Time?
  6. Is a Magnetic Field Uniform Across the Surface of a Tube Magnet?
  7. We Guarantee 100% Metal Separation
  8. You Can Block a Magnetic Field
  9. Magnetic Separators are Not Dangerous?!!?

Bunting Secures Record Export Order for Magnetic Separators

Bunting Magnetics Europe Ltd has secured their largest single export order from a German processing plant designer and builder.  The record order is to manufacture and supply 63, high-strength, Rare Earth Plate Magnets, which will be installed in a tobacco manufacturing operation in Indonesia.

Bunting Plate Magnets
Plate Magnets designed and manufactured by Bunting Magnetics for use in a tobacco processing plant overseas

The Plate Magnets are used to remove metal from the shredded tobacco.  Metal enters the tobacco process at various points, including at source, with the raw material infeed, and during the slicing and cutting of the leaves.  The Plate Magnets attract and hold the magnetically susceptible particles, including abraded stainless steel.  This prevents damage to delicate processing equipment such as the cutting blades as well as maintaining the quality of the end product.

The recent order in June 2016 was for 63 Rare Earth Plate Magnets and followed an earlier order for 26 placed in February 2016.  Another large Export order for Plate Magnets was secured in 2015.

Two different models of Plate Magnet are being supplied, with 34 having a magnetic face width of 609mm and a 125mm deep magnetic field and 29 with a face width of 508mm projecting a 90mm deep magnetic field.

A Plate Magnet comprises of a stainless steel box or housing into which high strength Rare Earth blocks are positioned.  The type of Rare Earth block and configuration of the blocks within the housing dictate the shape, strength, and depth of the magnetic field.  A deep magnetic field was important in this application.

Head of Sales, Dave Hills, explained the importance of the order:

“Developing export business is vital for our continued growth in the UK.  This is our single largest order for Magnetic Separators on record and is the result of a prolonged focus on developing business overseas.  On this project we worked closely with the German client and had several meetings in Germany to understand their requirements before we proposed the best metal separation solution.  This is a very exciting development for Bunting Magnetics in Europe.”

The Plate Magnets will be manufactured and supplied in batches in specially designed transportation boxes and are due to be despatched between June and August 2016.

For further details on the Bunting range of Magnetic Separators and Metal Detectors please contact our technical sales team on:

Bunting Plate Magnets
Plate Magnets designed and manufactured by Bunting Magnetics for use in a tobacco processing plant overseas

3 Types of Ferrous Metal Found in Plastics Recycling

Metal Removed by Magnetic Separators

Metal is a major cause of equipment damage, production downtime and poor end product quality, especially when recycling materials such as plastic.  So what types of metal can be found?  Here are 3 examples taken directly from a UK plastics recycling plant.

  1. Fine metal shards and even dust – The metal found on the face of this ultra strong Rare Earth Plate Magnet is quite fine and has been lifted up out of conveyed material.  Fine iron is difficult to separate and can cause significant wear to plant and also contaminate the final product.  In this particular installation, Plate Magnets were used both suspended above the conveyor and positioned in chutes (where material flows over the magnet face), but fine iron can also be removed using Drum Magnets;Fine_Iron_on_a_Bunting_Plate_Magnet
  1. Nuts, Bolts and Screws – This is a more typical example of metal contamination that tends to be either present in the delivered reclaimed plastic or introduced into the process from plant wear or during maintenance.  Nuts, blots and screws cause significant damage to process plant and can be costly in terms of equipment repair and production downtime.  In this installation, these ferrous metal items were removed from the product stream using a Magnetic Pulley although Drum Magnets are also used;Metal Found in Plastic Recycling Bunting Magnetics-2
  1. A Large Spanner – An extreme, but not unusual, example of metal contamination.  The damage that a tool such as a spanner can cause is huge in terms of cost and downtime.  Introducing a spanner into a shredder or granulator could have disastrous consequences.  The spanner in this photograph was separated using a Magnetic Pulley.  On other plants both Drum Magnets and Twin Pole Overband Magnets are commonly used;Metal Found in Plastic Recycling Bunting Magnetics-3

We are putting together a library of metal items that have been found in process lines and would welcome your feedback and photos.  Please send us your stories to press@buntingeurope.com and we will add these to this news blog on our website.

For further details on the Bunting range of Magnetic Separators and Metal Detectors please contact our technical sales team on:

Export Order for 12 Custom Plate Magnets

Removing Metal From Shredded Tobacco

Bunting Magnetics Europe Ltd has designed, manufactured and shipped 12 large and custom designed Self-Clean Plate Magnets to a customer in Italy for an export project in Indonesia.  The export order was valued at over £50,000 and was the result of close cooperation between the Bunting Europe engineering team based in Berkhamsted in the UK and the Italian customers engineers.

Bunting Magnetics Plate Magnets-0959

Plate Magnets are a simple form of Magnetic Separator with blocks of magnets magnetically arranged inside a rugged stainless steel fabricated housing to project a magnetic field on the flat surface of the plate.  The projected magnetic field captures both fine ferrous contamination and larger pieces of tramp ferrous metal from various types of free flowing material (including powdery, moist, lumpy, and abrasive products through to large material that might choke, bridge, or cause rapid wear in Magnetic Cartridge or Tube based separators).

For the Italian project, the objective was to remove tramp ferrous metal contamination from tobacco to protect damage to delicate and expensive cutter blades.  The product flow was poor with a high moisture content and so a Plate Magnet was the best suited design of Magnetic Separator for the application.  Due to specific application requirements, the Plate Magnet was custom designed to produce a specific shape and intensity of magnetic field.  Each Plate Magnet had a face of 600mm by 130mm with a depth of 45mm and weighed approx. 50kgs.  These were the largest Plate Magnets manufactured in the UK by Bunting.  The custom design, using high-energy rare earth magnets, meant that a peak magnetic field of over 10,000 gauss was produced on the surface, which was flat as recommended for low density product flows, inverted installations and sanitary applications.

The Plate Magnets were positioned inside chutes and due to the size and weight of each unit, the customer required each one to be self-cleaning, whereby any captured metal would be automatically removed and discarded.  The self-cleaning design requires a counter plate to be placed against the surface of the Plate Magnet.  During the self-cleaning process, both the counter plate and the main body of the Plate Magnet is pulled away from the chute then the counter plate is pulled away from the main body.  Any magnetically entrapped material is held against the counter plate and becomes demagnetized as the Plate Magnet moves away allowing the ferrous material to falls away into a discharge collection area.

The 12 identical Plate Magnets were designed, manufactured and despatched within 9 weeks.  The size, weight and magnetic strength of each Plate Magnet dictated that each unit had to be packed separately for shipment to Italy.

Dave Hill, Bunting’s Head of Sales, explained how Bunting secured the order.  “Being flexible and having the engineering capabilities in Europe to custom design the Plate Magnet for the client was vitally important.  Ultimately, that was the deciding factor.”

Plate Magnets are a very versatile and easy Magnetic Separators to install and use, providing very effective metal contamination protection.  For further information or to discuss a specific application, please contact us on: