Permanent overband magnetic separators DND-AC

Installation of an overhead magnet

Most commonly the crossbelt magnetic separators DND-AC is suspended above and across the belt, however it is also possible to place the overbelt magnetic separator at the head of the conveyor (parallel to the belt). The kind of applied magnets depends on the position of the separator: if the magnetic separator is parallel to the conveyor belt.

It is possible to use weaker magnets (as at the end of the conveyor belt the material is quite loose). On the contrary, if the overbelt magnet is suspended across the belt, we recommend that stronger magnets are applied (as the material layer on the belt might be higher and compacter).

The standard version of the overband magnetic separator DND-AC M is fitted with strong permanent ferrite magnets. However, if you need stronger magnetic force (e. g. for mobile lines, grinders, mills), we recommend that the overband magnetic separator is equipped with extremely powerful neodymium NdFeB magnets from rare earth ores. A careful interference shielding ensures that the magnetic field is concentrated only on the material on the conveyor belt.

Measuring magnetic separator power

We take pride in thorough testing each overband and measuring its magnetic performance. We know that it is important for our customers to know the magnet performance at different distances from the magnetic separator. That is why we do not state the magnetic induction values only at the magnetic core, but also at a distance of 0 to 400 mm (measured in 50 mm increments) from the separator belt.

We measure the magnetic flux density in such a way that it corresponds as faithfully as possible to real conditions. Therefore, we do not measure the magnetic induction only at the magnetic core (as some manufacturers do and artificially increase the value of the magnetic induction in this way). We measure the magnetic flux density at the above mentioned distances from the separator belt. Such piece of information is important to the customer.

The practically measured values of the magnetic induction are stated at the corresponding overbands in the website section “Gauss charts”.

Of course, we provide a test report with measured magnetic induction values for each separator.

Practical magnetic separator testing

The measured value of the magnetic induction is clear information, but for many customers, it is more important to know the kind of ferrous objects our separator can really separate. That is why we performed a set of tests to better demonstrate the strength and functionality of our overbands. We selected 13 typical ferromagnetic pieces that our customers most often need to separate (nuts, nails, wires, steel balls, etc.) and measured how the distance between the overband magnet and the ferrous objects affects the magnetic attraction (i. e., how far from the separator belt the test pieces can be trapped). 

See the website section “Practical testing” for this piece of information - we are sure that it will provide our client with all the data needed for the selection of the right overband magnet.

Of course, our specialists are ready to help you choose the appropriate type of the magnetic separator.

Recommendation: Connection of a magnetic plate and magnetic roll

In order to achieve the highest possible degree of separation, it is recommended that – especially in case of a higher layer of material on the conveyor belt – the overband magnet DND is combined with the magnetic pulley MV (that is able to attract ferromagnetic particles from lower material layers).

SOLLAU – our products are welded by real professionals!

SOLLAU certifications:  
Authorization to perform welding on pressure equipment according to PED 2014 / 68 / EU
Pressure welder certificate according to EN-ISO 3834 - 2, EN 1090 - 2, EN 13480 - 1 to 5, EN 13445 - 1 to 5

Ferrite overbands - transversal placement

The main benefits of ferrite overband magnets include the following: high temperature resistence, long-term magnetic stability, affordable price, deep and very strong magnetic field (in case of stronger models). This separator is designed to be installed across the conveyor.

Neodymium overbands - transversal placement

An extremely strong (but relatively short) magnetic field and a low weight are the most significant benefits of neodymium overband separators. That is why the application of the neodymium separators is preferred at the places where it would not be possible to use heavy ferrite magnets or where a very high separation efficiency at shallower depths is required (e. g., in cases of mobile crushing and recycling lines). This separator is designed to be installed across the conveyor.

Ferrite plates - longitudinal placement

The main benefits of ferrite overband magnets include the following: high temperature resistence, long-term magnetic stability, affordable price, deep and very strong magnetic field (in case of stronger models).

This separator is designed to be installed longitudinally with the conveyor. Thanks to the installation above the end of the conveyor belt, the material is separated as soon as it falls from the end conveyor roller and is thus more permeable. This has a positive impact on the quality of the magnetic separation. Sometimes it can be the only suitable solution of magnetic separation, e.g. for materials with poor bulk properties or when the layer of material transported by the conveyor is high.

We recommend replacing the end conveyor roller with a non-magnetic one to increase the efficiency of the magnetic separator and prevent unwanted magnetization of the conveyor roller.

DND-AC M F PANTHER

• DND-AC M1 F PANTHER
• DND-AC M5 F PANTHER

DND-AC Ms F JAGUAR

• DND-AC Ms2 F JAGUAR
• DND-AC Ms6 F JAGUAR

DND-AC Mm F TIGER

• DND-AC Mm3 F TIGER
• DND-AC Mm5 F TIGER

DND-AC Ms F EKO

• DND-AC Ms2 F EKO
• DND-AC Ms6 F EKO

DND-AC N JACKAL

• DND-AC N5 JACKAL

DND-AC Nm WOLF

• DND-AC Nm5 WOLF

• JACKAL is in action! Strong, lightweight and immediately available! (case study)
• Separation of metals from Solid Recovered Fuels (SRF) - the most powerful separator on a special price! (case study)
• Separation of magnetic and non-magnetic metals in a municipal incineration plant (case study)
• Separation of iron and aluminum cans from non-metallic contamination (case study)

Why overband magnets by SOLLAU?

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