Extracting foreign metal fragments from liquid lines

Magnattack Global

Friday, 27 April, 2018

Extracting foreign metal fragments from liquid lines

Hygienic and efficient metal fragment control in liquid processes without the limitations of liquid trap magnet systems.

Finger-style inline liquid trap magnets (also referred to as finger pot magnets) are a conventional way of extracting foreign metal fragments from liquid lines such as chocolate, soup, beverages and similar ingredients. They consist of a number of magnetic fingers/cartridges/tubes which are welded to a lid. The magnetic fingers are projected down into the flow and retain metal fragments as the liquid flows in, around and out of the pot magnet housing.

However, such magnetic trap magnets have a number of inherent problems that can have a negative effect on separation efficiency and metal fragment control. Users reported difficulty in handling bulk liquid magnet systems, found the time taken to clean multiple finger bars excessive and had experienced issues with magnet fingers becoming bent or, in some cases, breaking off.

Recognising these problems Magnattack decided to develop a modernised magnetic separation solution for use in liquids.

The solution

After consulting with users who were experiencing these difficulties, Magnattack developed the RE80 Liquid Pressure Pipeline System (PPS). The Liquid PPS features +11,000 Gauss magnet elements, designed to intercept the flow of liquid product lines. The RE80 probes successfully extract and retain foreign magnetic fragments such as work-hardened stainless steel and stone particles, fine wear fragments and rust.

The Liquid PPS Magnets offer hygienic and efficient magnetic separation and have proven to be a major success in efficiently removing foreign metal bodies from liquid lines in hundreds of applications over many years.

The PPS Systems have been proven effective in a wide variety of applications, some of which include syrups, chocolate, soup, sauce, beverages, viscous pet food slurries, ice-cream manufacturing, cheese processing, pie manufacturing, brine, fruit juice and food paste.

With the development of advanced magnetic separation systems, such as the RE80 Liquid Pressure Pipeline Magnet, the food industry can be assured of the highest level of metal contamination risk reduction without risking important sanitary and food safety considerations.

The systems are certified by HACCP International and conform to current industry food safety standards such as International Food Safety Standard 0909MAGSEP 1-2010.

Liquid Pressure Pipeline System v liquid trap magnets

Cleaning efficiency

Liquid trap magnets present cleaning difficulties due to numerous 1″ bars (typically 5–7 fingers). This has often resulted in contaminants being missed at cleaning intervals and has also made it difficult for operators to detect cracks or fatigue in the magnet fingers.

In comparison, Liquid PPSs feature only two, larger probes, therefore reducing cleaning and downtime. Each probe can be removed individually, ensuring it is able to be fully inspected and cleaned before being returned to the product flow. This system can also be CIP cleaned prior to cleaning of magnets.


Liquid trap magnets are often heavy and the entire pot lid must be removed for cleaning. This can potentially result in operator WHS risks. To overcome this, Liquid PPS probes are lightweight and operators need only to remove one probe at a time — therefore reducing the risk of injury caused by handling and lifting heavy equipment.

Leaks and blockages

Liquid trap magnet lids are necessarily large to incorporate multiple bars, so more force over a larger area incurs more lbs per sq inch pressure, which makes them harder to seal than BSM or tri-clamp connections. Most housings are cast stainless steel, which is magnetic. This hinders the entry and exit of the magnets, making it difficult to align for a good seal.

The Liquid PPS offers efficient magnetic separation without leaks, blockage or distortion. Also available within the PPS range is the well proven and patented tear drop probe magnets, that assist in flowability and also minimise bulk density breakdown. BSM or Triclovers seals are used to securely seal probes to the housing, therefore reducing the risk of leakage.


The ‘dead-zone’ in liquid trap magnets provides a space for contaminants and product to rest — this is often unhygienic and risks magnetic contamination returning to the product flow.

In contrast, the sanitary construction of the Liquid PPS System and high-intensity magnet elements installed at right angles eliminate dead-zone and increase magnetic separation efficiency with over 80% coverage of product stream as required by Food Safety Standard 0909MAGSEP 1-2010.


Breakage of magnet fingers is a frequently reported issue. Most liquid trap magnet designs consist of 1″ diameter magnet bars welded to the lid. Often, fatigue and accidental dropping of the magnet results in magnet fingers becoming dented, bent or broken.

The risk of damage is minimal in RE80 Liquid PPS Systems. They are constructed using solid structural fixing, larger diameter bars and structural welding techniques to avoid fatigue and breakage. In addition, the PPS comes with 3 years’ warranty on the magnet structural integrity.


In the case of one magnet finger becoming damaged, the entire pot lid and all fingers on a liquid trap system must be replaced. This can be a costly exercise.

In contrast, the Liquid PPS system is much more cost effective to repair as, in the unlikely event of damage, only one probe would need to be repaired or replaced.

Specialised focus

Magnattack Global technicians concentrate solely on the food, beverage and pharmaceutical industries. This specialised focus ensures that the company is able to provide a current, relevant and knowledgeable source in regards to foreign metal fragment control.

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