Practically Measuring Magnetic Separator Strength

Technically Assessing Magnetic Separator Power

A Magnetic Separator is designed to attract, capture and hold magnetic particles.  The magnetic strength needed to successfully achieve that design objective is commonly stated in a magnetic separator supplier’s quotation or specified in the tender.  This ‘Magnetic Strength’ is usually referenced in terms of ‘gauss’, a unit of measurement.  However, the ‘gauss’ value can be very difficult to accurately measure.

20180424_173613
Fine iron contamination captured on Tube Magnets

There is a more practical method of assessing the magnetic strength.  This removes any ambiguity whilst providing simple, repeatable, and comparable data to assess most Magnetic Separators.

Measuring Magnetic Strength

The magnetic strength of a Magnetic Separator is often referenced in terms of ‘gauss’.  Gauss (symbolized G) is the centimetre-gram-second (cgs) unit of magnetic flux density. A flux density of 1 G represents one maxwell per centimetre squared (1 Mx ­ cm -2 ).  It is named after the German scientist Carl Friedrich Gauss.

Gauss can be measured using a Gaussmeter.  However, it is important to note that the Gauss rating on its own does not fully indicate the strength of a magnet.  Additionally, gaussmeters can give a range of readings dependent upon the orientation of the probe and several other variable parameters.

Proposals for Tube Magnets often include details of length, diameter and the gauss reading.  With the gauss reading being so difficult to test and prove, purchasers and users are unable to check that the Tube Magnets supplied actually meet the specification of the quote and the order.

However, in terms of Magnetic Separation the objective for the user is simple; the magnetic force must enable the attraction and capture of any magnetically susceptible metal.  That ability can be measured as a function of the effort needed to remove a specific steel item from the surface.

The Method

Measuring the effort needed to remove a steel item from the face or surface of a Magnetic Separator is achieved using a spring balance and is commonly called a ‘Pull Test’.  The magnetic test piece (e.g. a 6mm ball bearing welded onto a non-magnetic attachment ring) is clipped onto the end of the spring balance.

Bunting Magnetics Pull Test Kit
A Pull Test Kit ‘Spring Balance’

The magnetic test piece is placed on the surface of the Magnetic Separator and force applied at the other end of the spring balance until it is detached.  The force required to remove the magnetic test piece (measured in kgs) is recorded on the measurement scale of the spring balance.

Measurements are taken in the centre of the Tube Magnet and on the end poles.  They are repeated three times and the average recorded as the force required to remove the magnetic test piece at each point.

The following video explains the Pull Test technique.

This simple but effective method does not record or provide any indication of the gauss, but accurately provides data that can be used to compare the condition of a Magnetic Separator over time and compare the performance with other similar designs.

Pull Test Experiments

Magnetic Separator designs vary considerably depending on the application.  The Pull Test technique is suitable for measuring the magnetic strength of smaller Magnetic Separators such as Tube or Cartridge Magnets and Plate Magnets.

Tube or Cartridge Magnets are often used stand alone or as part of a Magnetic Separator configuration (e.g. Drawer Filter or Liquid Trap).

Bunting Magnetics Pull Test Kit
Magnetic Test Piece

A small steel ball is used as the magnetic test piece when measuring the magnetic strength of a Tube or Cartridge Magnet (the photograph shows a 6mm diameter ball)

The metal test piece is attached to the end of the Spring Balance and then placed into the magnetic field, being attracted to the magnetic pole.

Bunting Magnetics Pull Test Kit
Magnetically Attracted Metal Test Piece

In a series of experiments, we used the Pull Test technique to assess the magnetic strength of Tube Magnets with Ceramic (Ferrite), Standard Neodymium Rare Earth, and High Strength Neodymium Rare Earth Magnets.

The tests were undertaken using three different sizes of steel ball in the magnetic test piece (6mm, 12mm and 25mm) and introduced non-magnetic spacer to assess the magnetic strength at specific distances away from the surface (3mm and 6mm).  All the recorded measurements are in kilograms (kg)

Ceramic (Ferrite)

Gap 6mm Ball 12mm Ball 25mm Ball
None 1.25 1.75 2.5
3mm NR NR 1.2
6mm NR NR NR

Graph - Ceramic Tube Magnet

Note:  all measurements are recorded in kilogrammes.

Standard Neodymium Rare Earth

Gap 6mm Ball 12mm Ball 25mm Ball
None 2 4.25 9
3mm 1.2 1.6 2.45
6mm NR 1.25 1.5

Graph - Std Neo Tube Magnet

Note:  all measurements are recorded in kilogrammes.

High Strength Neodymium Rare Earth

Gap 6mm Ball 12mm Ball 25mm Ball
None 3.75 9 14.5
3mm 1.5 2.5 4.6
6mm 1.1 1.5 2.25

Graph - High Strength Neo Tube Magnet

Note:  all measurements are recorded in kilogrammes.

In all cases, the drop off in magnetic strength as you move away from the surface of the Tube Magnet is significant and this highlights the need for metal contamination to come into contact with the surface.  Arrangements where the Tube Magnets are configured as a Grate (i.e. are lined up and equally spaced) commonly have a deflector above the gap between the Tubes that directs material in the area of maximum magnetic strength.

Comparison

The tests highlight the difference in magnetic strength on the surface, with high strength Rare Earth magnets producing nearly 3 times as much pull as Ceramic magnets.

Findings During Magnetic Separator Audits

Magnetic Separator Audits often highlight issues that had previously gone undetected.  The first check focuses on the physical integrity of the Magnetic Separator, inspecting welds, and assessing wear and damage.  Once these have been completed, the measurements are taken.

The most common findings when undertaking magnetic separator audits are:

Weld Failure

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Consequence of weld failure on a Liquid Magnetic Filter

Magnetic Liquid Filters, fitted into pipelines, have Tube Magnets that are welded to a lid and project down into the product flow.  Metal is attracted and captured on the surface of the Tube Magnet.

In cases where the welds have failed (e.g. poor manufacture, eaten away by acidic or alkaline liquids), liquid will seep into the tube and onto the magnets.  The magnets then swell and lose magnetic strength, ultimately splitting the outer stainless-steel casing.

Tube Magnet Wear

When material falls directly onto the surface of a Tube Magnet, over time the surface can be worn.  Wear usually occurs on the poles where magnetic particles have been captured.  Once the outer stainless-steel casing has been breached, the Tube Magnet should be replaced.

Weak Tube Magnets

Magnetic separation audits highlight the variance in magnetic strength of Tube Magnets.  Often, the Tube Magnets have been installed for some time and details of the original specification have been lost.  When testing the magnetic strength, some Tube Magnets are found to have very poor strength and provide little if no metal separation protection.  This is of great concern when the Tube Magnet is positioned to protect a particular item of processing plant where metal contamination damage could result in production downtime and costly repairs.

Conclusion

The Pull Test Experiments highlights the importance of physically checking the real magnetic strength of a Tube Magnet and not only replying on the stated gauss.  Including details of the force needed to detach a 6mm steel ball from the surface of the Tube Magnet in the request for quotation and the order, protects the user and ensures that the supplied equipment is as exactly as stated.

This ‘Pull Test’ measurement technique also enables a regular comparative test that will immediately highlight any drop in magnetic strength.  This can be used in annual audits or inspections as part of a plant’s quality management system.  A change in ‘pull’ strength may be the result of physical (e.g. failed weld, broken magnets from being dropped) or excessive heat.  The reduced magnetic force may result in the magnetic separator no longer being fit for purpose.

For further information on measuring the strength of a Magnetic Separator, please visit our website or contact us on:

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

Photographs taken and videos produced by Paul Fears Photography

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

Quality and Environmental Accreditation for Bunting Magnetics Europe

Bunting Successfully Transition to ISO9001 2015 Quality and ISO14001 2015 Environmental Standards

Bunting Magnetics Europe has successfully transitioned to the new ISO9001:2015 Quality and ISO 14001 :2015 Environment Standards.  The certification covers the manufacture and supply of Magnetic Separators, Metal Detectors, and Magnets and Magnetic Assemblies from their European manufacturing headquarters in Berkhamsted, UK.

Denis_Elkins_Bunting_Magnetics_Europe-2171

Denis Elkins, Bunting Magnetics Europe’s Quality Assurance Manager, explained the importance of transitioning to the ISO9001:2015 Quality standard.

“Bunting has held the ISO9001 quality standard since May 2005.  The quality of our products, manufacturing processes, and business management is of utmost importance to us and our customers, and, we believe, is one of the primary reasons for our continued success.”

The ISO 9001:2015 Quality Standard was revised in 2015 and now has a definitive focus on business performance.  The process approach has been combined with risk-based thinking, promoting the Plan-Do-Check-Act cycle at all levels in the organization.  The new standard acknowledges that modern organisations will have several management standards in place, and the 2015 version has been designed to be easily integrated with other management systems.  The new version also provides a solid base for sector-quality standards (automotive, aerospace, medical industries, etc.), and takes into account the needs of regulators.

Bunting also recognises the importance of adopting good working practices in accordance with international Environmental Standards and originally attained the ISO14001 standard in February 2002.  The ISO14001:2015 Environmental Standard sets out the criteria for a certifiable environmental management system.  It maps out a framework that a company or organization can follow to set up an effective environmental management system, regardless of its activity or sector.

“We have been actively involved in the environmental sector supplying metal recycling equipment for many years,” explained Denis, “and so maintaining this environment standard was simply common-sense.  As a UK manufacturing company we recognise that we have a responsibility to protect the environment and the standard provides the framework to implement, measure and manage the most effective methods of operation to reduce waste and pollution.”

For further details on Bunting Magnetics Europe Ltd or our range of Magnetic Separators and Metal Detectors, please contact our technical sales team 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:

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

28 In Line Magnets Remove Metal from Baby Food

Record Sales for In Line Magnets in 2016

A record 28 Pneumatic In-Line Magnets (PIMs) have been supplied to a major global Baby Food products company in Germany.  The Magnetic Separators are installed into food processing lines to attract and remove any magnetically susceptible materials.

Pneumatic_InLine_Magnet_Bunting_Europe-1608
2 PIMs ready for despatch to Germany

Metal is commonly found in food during processing.  The metal can originate from a breakdown of processing equipment (e.g. failure of a screen or pump), or even be delivered with the food raw materials.  The vast majority of food producers use Magnetic Separators and Metal Detectors to remove and detect any rogue metal before any food product leaves the production plant.

Pneumatic In-Line Magnets (PIMs) are specifically designed for installation into pneumatic conveying systems.  The 28 supplied for the Baby Food application are fitted with extremely powerful Neodymium Iron Boron Rare Earth Magnets.  These produce the highest magnetic field and capture even small shards of metal and work-hardened stainless steel.

The internal design of the PIM ensures that the product flow is not compromised.  The powerful flat-faced magnet with two tapered-steps is mounted on one side of the PIM and swings out from the body for easy cleaning.  To ensure there is no leakage during operation, the flat-faced magnet is held firmly into place by long-threaded bolts.

Bunting Magnetics In Line Magnet-10

The key design features of the PIM are:

  • Designed for unobstructed product flow;
  • Compression couplings speed in-line installation;
  • For dilute phase conveying up to 15 psi;
  • Best suited for horizontal installation;
  • Optional portable cart available for easy handling;
  • Powerful Rare Earth magnetic field covers entire cross-section of product flow;
  • High-energy Rare Earth tapered step plate magnets are standard;
  • Magnet swings out for easy cleaning;
  • All finishes available including food and sanitary;

Other articles discussing ‘Metal In Food’ include Green Beans Found Contaminated with Metal at Morrisons and Metal found in Sainsbury’s Bread.

For more information on the Pneumatic In-Line Magnet or any Magnetic Separator, please contact our team on:

Phone:  +44 (0) 1442 875081

Email:  sales@buntingeurope.com

Via the website

Bunting Magnetics In Line Magnet-25

10 Magnetic Separator Myths

Magnetic Separator Fact and Fiction

Trying to ascertain what and whose Magnetic Separator will provide the best metal separation can be difficult.  Often, the decision is made even more difficult with claims and counterclaims about levels of Gauss and what the Magnetic Separator can actually capture.  In this blog, we try to dispel these myths and make selecting the right Magnetic Separator a little easier.

Myth 1 – You Should Always Use the Strongest Magnetic Separator

Strongest is always best, or is it?  Commonly, companies will call and request a quote for a Magnetic Separator with the strongest magnet.  But is that actually what they need?

magnetic-pull-test-kit-bunting-magnetics-blog

Myth 2 – All Rare Earth Magnetic Separators Are The Same

A client has a metal contamination problem and needs to install the most suitable magnetic separation.  The metal is small and so they believe that a Magnetic Separator with Rare Earth Neodymium Magnets is what they need as this produces the strongest magnetic field.  So he picks up the phone and orders a Rare Earth Magnetic Separator and his problem is solved.  Or is it?

Myth 3 – The Highest Gauss Magnetic Separator Is Always The Best, Or Is It?

On a regular basis, we will receive an enquiry requesting a Magnetic Separator of a specific size.  However, it is only when the enquiry also requests a specific Gauss figure that it all starts becoming a little complicated.

Myth 4 – Stainless Steel Isn’t Magnetic, Or Is It?

The vast majority of stainless steel used in plants processing foodstuffs, chemicals, plastics and handling bulk materials whether in solid, liquid or powder form, is non-magnetic.  Or is it?bunting-ffs-magnet-with-stainless-steel-washer-and-wingnut-0086

 

Myth 5 – Do Magnets Lose Strength Over Time?

It is a question we frequently get asked:  When will the Magnetic Separator start losing its magnetic strength?  In normal operating conditions, a magnetic separator will not lose any magnetic strength.  However, there are occasions when other factors do affect the magnetic strength.

Myth 6 – Is A Magnetic Field Uniform Along the Surface of a Tube Magnet?

On a typical Cartridge or Tube Magnet, the magnetic field on the surface is not even along the whole length.  As shown on the photograph, magnetically attracted materials agglomerate at specific points along the length.  So why is that?

Myth 7 – We Guarantee 100% Metal Separation

In the perfect world, installing a Magnetic Separator will enable 100% metal separation with 0% product loss.  However, is this even remotely possible?

Myth 8 – You Can Block a Magnetic Field

A common question asked by users of Magnets and Magnetic Separators is whether a Magnetic Field can be blocked in the same way that lead blocks radiation.  This can be an important issue when considering the location of a Magnetic Separator and whether it is near instrumentation, control panels, or is in an area freely accessible by employees.

horseshow-magnet-1

Myth 9 – Magnetic Separators Are Not Dangerous?!??

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?

Myth 10 – It Is Easy To Clean a Magnetic Separator

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.

For further details on Magnetic Separator Myths or to discuss any Metal Contamination and Separation issue, please contact our technical sales team on:

100-with-a-smile

 

Getting Metal Out of Spices

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

Most households have a collection of spices in one of their kitchen cupboards.  Adding spices to food when cooking is now a common practice, but how are they processed and prepared?

Most spices are grown in the tropical regions of the world, with some thriving in the cool misty highlands. Many of the seed spices come from more temperate areas, such as coriander seed, which is grown in Northern India, Africa and the wheat producing areas of South Australia and Western New South Wales.

BUNT-2910 Perfect Plants 5

The nature of the location and how the spices are collected mean that there is a high risk of metal contamination.  Most spice plants use a series of Magnetic Separators and Metal Detectors to remove and detect any problematic metal.  Indeed, many UK supermarkets and food retailers (eg M & S) have strict guidelines on the use of Metal Removal equipment.

The plant shown in the flowsheet is a generalisation of a typical spice producing operation and highlights suitable locations for both Magnetic Separators and Metal Detectors.

On Delivery

Ideally, it is always best to remove metal before it enters the process.  The metal tends to be larger in size and easier to separate.  At this early stage, the delivered spices can be passed over a High Intensity Rare Earth Drum Magnet.  This automatically removes magnetically susceptible metal prior to the spices moving on to storage.

Prior to Processing

Metal damages processing equipment and so it is always best practice to ensure protection by installing a Magnetic Separator.  The spices can be passed over a simple Plate Magnet prior to grinding, protecting the grinding plates from damage.Plate Magnet Bunting Magnetics-9805

After Grinding

The process of grinding may liberate entrapped metal and may introduce fine iron into the process.  A Plate Housing Magnet followed by a Quicktron Metal Detector removes any metal.

At this stage, the spice may be sent directly to bagging.  There are several types of Magnetic Separator that are often used to ensure a metal-free product including a Pneumatic In-Line Magnet on the pneumatic line, and a Grate Magnet or Plate Housing Magnet just prior to packing.  A FS Metal Detector can also be used to remove any non-magnetic contamination.

After MixingBunting Magnetics In Line Magnet-2

Once the spices are mixed into a blend, they can be passed through a Centre Flow In-Line Magnet and Quicktron Metal Detector prior to storage in drums or containers.  Prior to the spices being bottled, a final stage of Magnetic Separation is often used.  This is commonly a form of Grate Magnet followed by a Quicktron Metal Detector.  The final check on the bottled spice is often undertaken using a conveyor-type Metron C Metal Detector.  The bottles are then packed ready for despatch.

The multiple stages of Metal Separation may appear excessive, but are required due to the nature of the process.  Metal in a wide variety of forms can be introduced at any stage in the process, especially after grinding and mixing.  Installing different designs of Magnetic Separator and Metal Detector at different points in the process will ensure the best protection against metal contamination.

For further information on removing Metal from a Spice processing plant 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:

 

 

 

 

 

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?!!?