Electro Drum Magnets
Bunting’s Electro Drum Magnets are heavy-duty magnetic separators suitable for applications in the automotive recycling industry as well as the aggregate, mining, and minerals industries. These heavy-duty magnetic separators are designed to separate and recover large pieces of ferrous tramp metal out of the product stream. Our current range of Electro Drum Magnets is the result of decades of continuous design improvement that we have achieved by working closely with our customers in order to create the best product for their unique needs. Today, we offer two models of Electro Drum Magnets: the FED, or Frag Electro Drum, and the SED, or Slag Electro Drum.
Bunting’s Electro Drum Magnets start off with a non-magnetic shell (commonly made of manganese steel) that is fitted with welded stainless-steel wiper bars. Within this shell are stationary electromagnetic coils, which the shell then rotates around at a speed that is determined by the diameter and the volume of material being processed.
We have computer designed our electromagnetic coil in order to achieve maximum energy and induction efficiency. The design of this coil features a mild steel core that is wound with either anodized aluminum foil or Nomex covered aluminum wire, which has an insulation above class ‘H’. While the covers surrounding it are rotating, the magnet system itself remains stationary.
To achieve specific separation goals customers may have, Bunting offers two different models of Electro Drum Magnet:
The FED, or Frag Electro Drum, is designed to provide maximum purity of recovered ferrous metals. It continuously removes ferrous metals from a product stream using an alternate pole design. This method maximizes ferrous purity. It is typically used in applications such municipal recycling and automobile recycling facilities where the ferrous fraction is recovered from the shredded material stream.
The SED, or Slag Electro Drum, is designed to achieve maximum recovery of ferrous metals. It has a radial pole design that maximizes ferrous metal separation by firmly holding metal to the drum shell throughout the entire 180-degree cycle.
Bunting’s Electro Drum Magnets have been designed to take on the most difficult, heavy-duty applications, and are specifically designed to handle large, irregular pieces of ferrous tramp metal. Large, heavy pieces of ferrous metal require a very strong and deep magnetic field to pull them out of the material stream. The Electro Drum Magnet generates this powerful magnetic field using its electromagnetic coils.
When Electro Drum Magnets are operating, material is fed onto the drum at one out of three different points (depending on what your process configuration is). Below, we explain the three types of feeding arrangements:
1) Material is fed onto the top of the Electro Drum Magnet. The drum shell attracts and holds magnetic material to its surface before discharging it beneath the drum.
2) Magnetic material is fed onto the center of the Electro Drum Magnet. The magnetic material that is attracted is rotated up over the magnet and is discharged opposite to the in feed.
3) Magnetic material is fed beneath the Electro Drum Magnet which snaps the ferrous material up to the drum. The drum shell captures and holds magnetic material to its surface. Then, the material is carried up and discharged over the top of the drum.
In all three configurations, and non-magnetic materials simply free-fall down and forward following their normal trajectory.
Bunting offers two models of Electro Drum Magnets, designed to suit specific applications.
Model FED (Frag Electro Drum)
The design of the FED features one single main coil that stretches the full width of the drum. This produces an alternating polarity along with a single auxiliary coil. This design is best suited to situations where magnetic materials may be burying or entrapping non-magnetic materials. FED Frag Drums are designed so that extracted magnetic materials roll over the face of the drum. This releases any non-magnetic materials that may be caught between ferrous material and the magnet’s face.
The design has asymmetric bipolar coils that consist of a main coil. This main coil concentrates maximum flux at the point of extraction. Then, a secondary coil works to ensure that ferrous material is carried around the drum and reaches its appropriate discharge point.
The magnetic field here alternates—this “flips” the magnetic material while it is traveling around the drum. By doing this, stray non-magnetic particles fall or are removed from the product stream. This produces a cleaner magnet product.
The coils are ducted between the core and the coil, as well as between the coils themselves. This maximizes the heat dissipation of the coil and results in a higher efficiency magnet. This coiling system also minimizes the gradient from any surface, which results in significantly reduced hot spot temperatures.
Key design features include:
• Axial pole design provides continuous high field strength at the separation zone. Effective magnet width is maximized as a result, ensuring even cover wear and minimum burden depth of material.
• High-intensity primary coil concentrates maximum flux at extraction point, while the lower-intensity secondary coil facilitates transport of ferrous material to discharge point.
• Ducted coils provide improved coiling, resulting in a low winding temperature that permits higher intensity and a longer coil life.
• Wear covers are 8mm thick (minimum) in manganese steel, and incorporates bolted joints to allow easy cover replacement.
Model SED (Slag Electro Drum)
The Slag Electro Drum Magnet, or SED, features two or more symmetrical coils (depending on width) that produce a continual radial pole.
The magnet system on the SED was specially designed by our engineers using computer design software in order to maximize efficiency. This magnet system consists of a mild steel core that is wound with anodized aluminum foil. While the covers rotate, the magnet system itself remains stationary. The 2, 3, or 4 coil, continuous pole design, is made up of coils that concentrate maximum flux at the point of extraction. At the same time, an extension pole ensures that magnetic material is carried around the drum where it reaches the point of discharge. By arranging poles radially over the width of the drum, the highest level of separation is achieved and maximum entrapment of metals is ensured as a result.
Additional features of the SED include:
• Main shell cover with robust construction. The shell cover is fabricated from 8mm thick wear-resistant manganese steel which is fully welded to the end flanges.
• Wear cover: Similarly constructed from 8mm thick wear resistant manganese steel, this wear cover has bolted joints that allow ease of replacement. On the wear cover, there are wiper bars fitted across the whole width of the shell, as well as at regular intervals around the drum shell’s circumference.
• Low carbon steel end flanges have one end fitted with an inspection cover, facilitating easy visual inspection of the coil and windings.
• Copper split flange bearings allow easy maintenance.
• Fixed bearings: Pedestal bearings with locking rings clamp the magnet securely in its working position.
• Easy Adjustment: An adjuster arm makes it easy to adjust the position of the magnet system within the drum, and this arm is fitted with a turnbuckle and cone locking ring. The customer may set the magnet position and thus the discharge of ferrous metals in accordance with their discharge chutes, which ensures maximum separation efficiency.
• Drive: A BS Pitched Simplex platewheel is bolted to a robust drive ring.
• Power Supply: 380/415v, 3ph, 50Hz or 230/460v, 3ph, 60 hz.
• Finish: Steel is finished with one coat of primer and two coats of RAL high performance alkyd enamel.
The transformer rectifier works to provide power to the magnet at the correct Amps. This is dependent on magnet design, input voltage, and ambient temperature.
• The tank is a fully welded steel enclosure to IP65, and has a bolted lid for easy access to oil and components. For easy oil changes, the oil level gauge is fitted to the front of the tank and a drain plug is provided.
• The terminal chamber on the front of the tank houses incoming AC and outgoing DC terminals. Taps are located inside the chamber, allowing outgoing DC voltage to be changed.
• Double wound transformer to BS EN 60076.
• The silicone diode, full wave bridge connected rectifier is stack mounted on an aluminum heat sink to BS 4417 ABCD.
• Diode protection is equipped with fast-acting semi-conductor fuses. The surge suppression is fitted to protect diodes against surges from the magnet coil following switch off.
• Steel is finished with one coat of primer and two coats of RAL high performance alkyd enamel.
• Starter box that features a start/stop button, a lockable isolator, and a current sensing relay to detect magnet low power and overloads, with terminals provided for remote access.
• To prevent side spillage, 150mm high spillage rings can be fitted to the end flanges. These rings are fabricated in sections, allowing easy replacement if damaged.
• Drum can be mounted onto a base frame and supplied complete with geared motor, chain dive, and guard.
• To reduce downtime, a split platewheel can be provided for easy replacement. Platewheel may be ANSI if required.
Electro Drum Magnets are widely used in the recycling industry, especially in environments that are particularly difficult and arduous. Some examples include:
• Automobile and vehicle recycling and recovery facilities
• Municipal waste and recycling facilities
• Steelworks recovery facilities