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

 

 

 

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:

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:

Getting Metal Out of Chocolate

A Guide to the Best Locations for Magnetic Separators and Metal Detectors in a Chocolate Production Line

Chocolate is made from the exceptionally hard cocoa bean and this means that metal gets introduced into the process, especially from equipment wear.  However, a series of carefully selected and placed Metal Detectors and Magnetic Separators will remove any metal from the process before it becomes a bar that is loved by millions.

Magnetic Separator Location in a Chocolate Production Line
The locations for Magnetic Separators in a chocolate production process line

The Stages of Metal Removal

Stage 1 – When the cocoa beans are discharged from the delivery vessel, metal is removed by passing all the beans through a heavy duty Grate Magnet.  This captures any larger ferrous metal, like nails, nuts and bolts.

Stage 2 – After the cocoa beans have been cleaned and roasted, they are cracked with the shells being discarded and the nuts being fed into the process.  After cracking, the nuts can be fed on a conveyor through a Metal Detector (Metron C) before passing onto the grinder.  This protects the grinder from being damaged by metal freed in the cracking process.

Stage 3 – After the grinder, the nuts have been converted into a chocolate liquor.  The process of grinding will introduce fine metal into the process and this is removed with a Magnetic Liquid Trap followed by a P-Tron Metal Detector.

Liquid Chocolate Magnetic Trap
A Bunting Magnetic Liquid Trap with a Waterjacket

Stage 4 – The chocolate liquor passes through a hydraulic press where it is split into cocoa butter and cake for cocoa powder.  The cocoa cake is fed onto a grinder and screen with the packaged cocoa powder being passed through a Metal Detector Metron C on a conveyor as a final check.

Stage 5 – The cocoa butter is fed onto a mixer where sugar, milk and flavouring is added.  After mixing and passing through a series of rollers, the mixture is emulsified before being heated.  This molten hot mix is then passed through a Magnetic Liquid Trap with a waterjacket (the hot water in the waterjacket stops any material from cooling).   Care has to be taken in selecting the right magnets as high temperatures can irreversibly damage the magnetic field.  The magnets must be suitable for use in high temperature environments.  After the Magnetic Liquid Trap, the mixture is passed through a P-Tron Metal Detector to detect any non-ferrous metal that may still be present.  This joint protection is important to prevent damage to the next stage of the process (the moulds).

Stage 6 – After the chocolate is fed into moulds it is then cooled.  The final check is after cooling, when the moulded and formed chocolate is then fed on a conveyor through a Metal Detector (Metron C).  The metal-free chocolate is then packaging and despatched for sale to the millions of chocolate lovers all over the world.

Multi-stage Metal Detection and Magnetic Separation may appear excessive, but the best way to remove all metal from the process is to focus on areas where metal may be introduced or released as part of the production process.

For further information on ‘Getting Metal Out’ of Chocolate or any foodstuffs, please contact us on:

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