3 Magnet Audits Conducted For Food Safety

Testing Magnetic Separators in Food Processing Plants

In one week, we have conducted Magnetic Separation Audits at three separate UK food processing plants.  The audits form part of the quality management system of each company and are used for both internal and external food quality and safety assessments.

A Magnetic Separation Audit involves the physical testing and inspection of all Magnetic Separators.

Physically Testing the Magnetic Strength

The first part of the inspection assesses the magnetic strength.  This involves using a Pull Test Kit which includes a spring balance and various sizes and shapes of magnetically susceptible steel test pieces.  A Gauss Meter is not used as the readings can be inaccurate and variable.  The physical test involves placing the steel test piece on the surface of the magnet (on a magnetic pole) and measuring the amount of force (in kgs) that is needed to remove the item from the surface of the magnet.  This is then repeated and an average reading recorded.

Visually Assessing the Magnet

The second set of tests involve the visual inspection of the Magnetic Separators and we are checking for:

  • The amount of metal contamination captured by the Magnet;
  • Signs of damage or wear;
  • Weld integrity;
  • Fixings and any related safety issues (e.g. missing restraining nuts);
  • Cleaning regimes and ease of cleaning;

Findings

In the three recent audits there were a number of findings including:

  • Magnetic Separators were in locations where it was extremely difficult to clean and may be considered a safety risk;
  • Welds on a Magnetic Separator had been eaten away by the acidic product resulting in liquid penetrating the Tube Magnet.  This caused the magnets to expand within the stainless steel casing and also destroyed the magnetic field;
  • Damaged Tube Magnets
    Tube Magnets where the welds have failed and liquid has seeped inside the stainless steel casing causing the magnets to expand and lose all magnetic strength
  • The magnetic strength of some Magnetic Separators (especially those that had been installed for some time) was very poor and the level of separation would be minimal;
  • In some locations, Magnetic Separators had been removed from the process but were still registered in the system;
  • The positioning of some Magnetic Separators could be changed to improve the metal separation performance;

Action

Following the Magnetic Separation Audit, a full report, with all the test results, is written and submitted with recommendations.  This then forms part of the food processing company’s internal quality audit system and is refereed to when there are inspections from external third parties and customers.  Commonly the audit is repeated on a annual basis using the same test parameters.

Similar audits are also undertaken in other industries including Plastics Production and Recycling.  An annual health check ensures that the Magnetic Separators are performing to their maximum potential and achieving the separation goals for which they were originally installed.

For more information on the issue of Metal Contamination and Metal Separation, 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

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

 

 

 

Developing Business in Poland at SyMas 2017

Bunting Support TEKPRO at International Trade Fair for Powder & Bulk Solids Technologies in Krakow, Poland

As part of their export business development strategy, Tom Higginbottom from Bunting will be supporting their Polish distributor TEKPRO at SyMas, the powder and bulk solids trade fair in Krakow, Poland (18-19 October 2017).

SyMas is an international exhibition focused on the processing, transport and storage of bulk goods, powders and granules.  TEKPRO are on stand A68.Bunting_at_SyMas17-2

Company TEKPRO Sp. z.o.o. was founded in March 2007 by Danish company TEKEMAS A/S  and the Swiss Dietrich Engineering Consultants sa .  They specialise in providing individual equipment and complete plants to handle and process bulk materials to the Polish market.

“Attending the exhibition and supporting the TEKPRO team is very important,” explained Bunting’s Sales Engineer Tom Higginbottom.  “Being at SyMas allows us to gain an understanding of the market, meeting existing and potential customers, and discussing the industry in general.”

Bunting_at_SyMas17-1TEKPRO will be displaying Bunting FF Drawer Filters and Grate Magnets on the stand.  Tom and the TEKPRO sales team will be giving advice to visitors about eradicating the problem of metal contamination using both Magnetic Separators and Metal Detectors.

“Over the next 2-days it will be great to have an opportunity to get to know the TEKPRO team.  We will also take the opportunity to provide some additional training.  We are really looking forward to the show, and spending time in a very beautiful city,” said Tom.

For further information on removing metal contamination from bulk goods, powders and granules with Magnetic Separators and Metal Detectors please visit the TEKPRO stand at SyMas or contact us on:

Other relevant Bulk Goods, Powders and Granules Articles

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:

Temperature Effect on Rare Earth Magnetic Separators

Neodymium Magnet Damage From High Temperatures

If a Neodymium Rare Earth Tube Magnet is put into a red-hot fire, then it would not be surprising if the magnetic properties are destroyed.  However, what if the same Tube Magnet is just exposed to steam being flushed through a pipeline system to clean the pipes?

Tube Magnets manufactured with high quality Neodymium Magnets are able to operate well in temperatures up to 100 degrees C.  There is a gradual drop in magnetic strength when the temperature rises above 80 degrees C, but this loss in magnetic strength recovers when the temperature falls back to normal levels.

However, as soon as the Neodymium Rare Earth Tube Magnets are exposed to temperatures exceeding 100 degrees C, the magnetic strength becomes compromised.  On returning to normal operating temperatures below 80 degrees C, there is an irreversible loss in magnetic strength and permanent damage.

Bunting Magnetic Liquid TrapIn a pipeline which is cleaned using steam, the temperature will be above 100 degrees C for a period of time.  This will certainly damage any standard Neodymium Rare Earth Tube Magnets or Magnetic Separators (e.g. the Magnetic Liquid Filter) installed in the pipeline.  However, most users are totally unaware of the potential loss in magnetic separation performance and that the ability of the Magnetic Separator to remove small pieces of metal contamination has been permanently compromised.

Magnetic Separators in High Temperature Environments

There are types of Neodymium Rare Earth Magnets that are designed to operate in high temperature environments.  These tend to be lower in magnetic strength at room temperature, but the magnetic field does not degrade as quickly as standard Neodymium Magnets at higher temperatures.  Also, on returning to normal temperatures, there is only a small irreversible loss in magnetic field, which is only experienced when first exposed to high temperatures.

This type of high temperature Neodymium Rare Earth Magnet should be used in pipelines which are being cleaned for prolonged periods with steam.

Tube_Magnet_FireFor applications where there are extreme high temperatures (exceeding 150 degrees C), then the best option is to use Samarium Cobalt Rare Earth Magnets (SmCo).  These retain their magnetic properties in temperatures up to 300 degrees C.  However, such applications are rare.

It is recommended that the magnetic properties and strength of any Magnetic Separator installed in a pipeline cleaned with steam or in an environment where there is constant exposure to high temperatures is checked on a regular basis (e.g. during an annual Magnetic Separation Audit).  The best way to do this is with a Magnetic Pull Test Kit.

For further details on Magnetic Separators designed for high temperature applications, please contact our technical sales team on:

Metal Found In Rice

Magnetic Separator Ensuring Food Safety

There are a lot of negative Food Safety reports about metal being found in food (e.g. Morrisons’ Green Beans, Sainsbury’s Bread), but there is also a great deal of good practice.

Whilst undertaking an annual Magnetic Separation Survey at a rice processing factory, we were able to see the importance of installing metal separation equipment.

Fine Iron on Bunting Grate MagnetThe Food Processor had installed Bunting FF Drawer Grate Magnets at the base of hoppers holding Basmati rice prior to packing.  For maximum fine iron removal, the Grate Magnets were constructed with high strength Rare Earth Magnets with magnetic fields of approximately 11,200 Gauss on the surface.

A schedule had been established for the Grate Magnets to be cleaned on a weekly basis.  During the Survey, the amount of fine iron captured and held onto the surface of each of the Tube Magnets was found to be  substantial.  Subsequently, one of the recommendations was to increase the cleaning frequency.  This would then ensure that the Magnetic Separators were working optimally as performance can drop if the Magnets are laden with captured metal.

Where Does the Metal Come From?

Fine Iron on Bunting Grate MagnetThe majority of rice processed in the UK is imported from South-East Asia.  The process of collection, storage and transportation results in fine iron being introduced.  Additionally, very small amounts of fine iron may be introduced during the handling of the rice at the UK plant.  This could be from the wear of processing equipment.

Does the Amount of Metal Vary?

The UK food processor has very little control on the amount of metal present in the delivered rice and even working closely with the rice grower to improve Food Safety standards does not ensure a metal-free product.  As with all food imports, there are many stages of handling and storage where metal contamination occurs.  The amount of metal can vary significantly and, subsequently, the frequency of cleaning the Magnetic Separators will alter.

Good Food Safety Practice

As demonstrated at this rice processing plant, Magnetic Separators will separate magnetically susceptible metal (including work-hardened stainless steel) prior to any product reaching the consumer.  Annual reviews with the suppliers of the equipment will provide assurance of metal-separation performance.

For more information on good Food Safety practices and removing metal contamination, or to request a Magnetic Separation Audit, please contact the Bunting team on:

Phone:  +44 (0) 1442 875081

Email:  sales@buntingeurope.com

Via the website

Fine Iron on Bunting Grate Magnet
Fine iron captured by a Bunting Magnetics Europe Rare Earth FF Drawer Grate Magnet

Bunting Magnetics Review of Southern Manufacturing 2017

Southern Manufacturing 2017 News and Views

The 2017 Southern Manufacturing & Electronics Show held at FIVE in Farnborough, UK (21st to 23rd March) proved to be a great place to showcase Magnets, Magnetic Assemblies, and Magnetic Separators.

The 2017 Show was of a similar size to 2016 with a good number of visitors.  One of the highlights of the Show was the wide range of 3D printers.  They included UV curing systems, double material heads, and fibre impregnated polymers.

On the Bunting stand, we found that people were looking for inspiration and one of the most common questions was ‘How can we use Magnets to fix a problem?’

“Being at the show gave us the opportunity to talk through potential applications with customers,” explained our Technical Sales Engineer, Matthew Swallow.  “One customer involved in mouldings was looking for high temp magnets that could operate above 300 degrees.  We talked to them about Samarium Cobalt (SmCo), which is specifically designed for use in high temperature applications up to 350 degrees.  We are now working with them on the project.”

“We also met a company who were searching for an alternative to a bonded radially magnetised magnet with the objective of giving their motorbike more power.  They were not aware that the new radial sintered Neodymium Magnets are over 4.5 times more powerful.”

Bunting Teardrop Tube MagnetThere was a great deal of interest in the recently launched Teardrop Tube Magnet.  The new Magnetic Separation is used in processing plants to capture fine magnetic contamination.  The ‘Tear’ design is ideal when processing fine powders that have a tendency to bridge.

“We simply would not have got some enquiries if we were not at the show,” said Matthew.  “On one project, we were generally speaking with an existing customer who then mentioned the need for a much stronger sintered Neodymium Magnet.  However, they were really concerned about the subsequent assembly difficulties and safety implications.  They were unaware that we build Magnetic Assemblies and we are now in the process of arranging for the customer to send us the metal work for us to assemble.”

As a showcase for UK manufacturing, the Show proved to be a great success.

For further information on Magnets, Magnetic Assemblies, or Magnetic Separators, please contact our Technical Sales Team on:

Bunting_Magnetics_at_Southern_Manufacturing_2017-1675

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?!!?

Magnetic Separators Are Not Dangerous!??

9th of 10 Magnetic Separation Myths

In school science, we learn about magnetism by playing with small permanent magnets.  It is fun, seeing how iron filings are affected by the magnetic field.  Our bodies are also constantly exposed to the Earth’s Magnetic Field.

So how can Magnets be dangerous?

In the 1980s, the concept of permanent magnetism changed with the development of the ‘Rare Earth Magnet‘.  The new permanent magnets produced a Magnetic Field and Force far higher than traditional Ferrite or Ceramic Magnets.

Since the 1980s, the magnetic strength of Rare Earth Magnets, like the Neodymium Iron Boron type, has increased.  Tube or Cartridge Magnets (as used in Magnetic Separators like Grate Magnets and Drawer Magnets) commonly use Rare Earth Magnets.  The high permanent magnetic force enables the attraction and capture of very fine or weakly magnetic materials.  This is vitally important when processing and producing plastics, foodstuffs or pharmaceuticals.

Bunting Magnetics Europe Ltd FFS Magnet-0095

But are they dangerous?

A strong Tube or Cartridge ‘Rare Earth’ Magnet has a surface magnetic reading of around 12,000 gauss.  The ‘Ferrite’ type has a surface field of 1,500 gauss.  In terms of magnetic force, the difference is enormous.

However, the real test comes when using a spring balance to pull a small steel ball bearing off the surface of the Tube Magnet.  When the steel ball is pulled off the Ferrite Tube Magnet, the force needed is negligible.  On testing the Rare Earth Tube Magnet, over 2kg of force is required.

Now we know that magnets attract.  So if two Rare Earth Tube Magnets are placed near each other, they will naturally want to go together.  The speed of the two items moving towards each other increases until they meet and the resultant collision is substantial.  If a hand or finger is in between the two Tube Magnets, the force of the attraction could result in serious injury.  People have been known to break or badly bruise fingers just by having them caught between two attracting Rare Earth Magnets.

So, the answer is a loud yes.  Magnets can be dangerous.  Luckily, advice and guidance is provided when advising users about Magnetic Separators.  And many Magnetic Separator designs include excellent safety features.

For further information on Rare Earth Magnets, Magnetic Separators, and Safety Advice, please contact us on:

Phone: +44 (0) 1442 875081
Email: sales@buntingeurope.com
Via the website

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