Magnet sweepers use magnets to pick up ferrous materials, like nails, screws, nuts and bolts. They can be quite useful around the house or jobsite and can help prevent popped tires or damage to machines. The setup is quite simple, so we decided to make one!
We knew we needed a removable/hinged cover for the magnets. A cover protects the magnets from damage, but more importantly it creates a way to remove the attracted materials easily. Without a cover, we'd have to remove each nail or screw one by one. That's not something we want to do with rusty junk picked up with a magnetic sweeper! We used a scrap piece of aluminum sheet metal, bent to fit our sweeper. We screwed the aluminum cover on each end to create a movable hinge.
We attached a thin steel sheet to the bottom of the wood, allowing us to just stick magnets right to it. This made it easier to test out various magnets. Countersunk Magnets can be a better, permanent option.
You could use smaller magnets, but they wont reach across the same distance with as much force as larger magnets do. If you decrease the magnet size, youd also want to decrease the gap between the magnets and the ground. The magnets in our sweeper are about 2 off of the ground. That may not seem like much distance, but our sweeper has trouble picking up tiny steel balls from 2" away!
The strength also depends on the size of the object and the amount of ferrous material in that object. Youll see more pull force to a large, thick steel washer than to a small staple! We talk a bit about this in our previous Magnetic Grates and Magnets vs. Steel articles.
Why is this? If we consider the field lines of a magnet a magnetic circuit, this can help us see why configuration one doesnt perform well at all. The magnet circuit shorts itself. The fields flow from one magnet to the next and dont extend very far at all.
The second configuration placed one row of magnets with their north poles facing the ground and the second row with their south poles facing the ground. This created a strong field in the middle of the rows as the field flows from one row field to the next.
We thought we would come up with some conclusive data pointing to which configuration worked best but it turns out that it can depend on distance (again). Configuration three measured best at 2 away, while configuration two measured best at 1 away. Configuration one didnt do as well in either tests.
Plate magnets can be placed in chutes, over conveyor belts and below conveyor drive pulleys. Chute installation kits can include a pre-drilled piano style hinge and a handle. Installed in suspended position, plate magnets include four welded eyebolts.
These magnets are provided in different strength and sizes. Product depth and the distance away from the product determine the strength. Shallower product depth provides better separation of ferrous metals from product. The size is determined by chute or conveyor belt width. The most common plate magnets are listed in the tables below. They are also offered with three different faces (collection area).
Ourmagnetic platesare the simplest and cheapest equipment for the protection of the installations of crushing and milling. The permanent magnet provides the following advantages: no consumption of energy, constant magnetic field, no maintenance and possibility to work in any place.
Suspended Plate Magnet Suspended Plate are designed for effective tramp metals extraction from the high volume material by installation above Conveyors. Using big size ferrite and properly designed configuration ensure the tramp iron can be taken from thick layer material flow by heavy duty plate. For fine metal powders in thin layer materialflow, light duty plate made of rare earth magnet is available also.
Can be installed in chutes, feed tables or over conveyor belts. Choose magnet strengths and sizes to match your requirements. Hinged plates swing out for easy cleaning. Self-cleaning models save downtime and labor.
Magnetic Chute, Chute Magnet, Hammer Mill Plate Magnet, Underflow Magnet, Plate Magnet, Quick-Clean Plate Magnets, Food Grade Magnetic Plate China Supplier Magnetic Chute (Hammer Mill Plate Magnet) extracts Tramp Iron from chopped sugar cane during processing to ensure that crushing rolls are not damages and that crushing rolls are not damages and that the finished 
Plate Magnets, Magnetic Plate, Magnetic Plate Separator, Flat Face, Pole Face, Tapered Step Face, Standard Permanent Plate Magnets China Supplier Plate Magnets are used to remove ferrous fines, as well as large pieces of tramp iron, from many types of free-flowing and pneumatically conveyed material. Bunting Plate Magnets are easily installed in enclosed flow lines. 
Tapered Step Face Magnetic Plate, Spout Plate Magnets, Single-step and Double-step Plate Magnets, Magnetic Separator Plates China Supplier Tapered Step Face Plate Magnets feature a diverter to provide maximum tramp metal separation and superior wash-off protection for high volume, below-the-flow applications. The diverter protects collected metal from being washed back into the product flow, while 
Suspended Plate Magnet Separator, Strong Magnet Suspended Permanent Magnetic Separator, suspended permanent magnetic iron separator, strong plate magnet, Armenia auto dry drum suspended magnetic separator, magnetic plate China Supplier HSRCYB series permanent Suspended Plate Magnet Separator is suitable for continuous-duty occasions with few iron materials to be removed. This equipment has a strong magnetic field 
Customized Permanent Magnetic Plates, Customer Standard PlateMagnet,Rare Earth NdFeB Magnet Separator Suspended Plate Magnetic Plate / Block Underflow Magnet,Magnetic Plate Separators,Conveyor Magnet Plate,Chute Magnet These units are designed to be positioned on the underside of angled chutes, product drop off points or opposite each other to form a housed chute magnet. Customized Permanent Magnetic Plates 
Overhead Plate Conveyor Magnets, Overhead Plate Magnets, Conveyor Magnets, Suspension Magnet, Forklift Magnet, Tramp Metal Magnet,Permanent-Type Recovery Magnet Overhead Plate Conveyor Magnets Overhead plate magnets are designed to remove ferrous contamination from conveyed product Applications: Overhead plate magnets are designed to remove ferrous contamination from conveyed product on a conveyor belt or open chutes, 
Suspension Magnet, Suspension Permanent Magnets Separator,Suspended PlateMagnet,Suspended Magnetic Separator Plates,Suspension Separator Suspension Magnet are designed for high separation performance in over-the- belt conveyor applications. These heavy duty permanent magnets incorporation all welded construction are particularly effective in removing tramp metal in high volume applications. Produces strong magnetic field attraction. The separator body adopts rare earth 
Suspended Plate Magnet,Manual Cleaning Suspended Magnets,OverbandSuspension Magnet,Suspended Permanent Magnet,Heavy DutyIndustrial Suspended Magnetic Separator Plates Suspended Plate Magnet are designed for effective tramp metals extraction from the high volume material by installation above Conveyors. Using big size ferrite or Ndfeb and properly designed configuration ensure the tramp iron can be taken from thick layer material flow 
Spout Plate Magnets,Tapered Step Face Magnetic Plates, Single-step OR Double-step Plate Magnet, Spout Magnet, Ramp Pole Surface Magnetic Plate Separator, Tramp Magnet Spout Plate Magnets feature a diverter to provide maximum tramp metal separation and superior wash-off protection for high volume, below-the-flow applications. The diverter protects collected metal from being washed back into the product 
Rare Earth & Ceramic Exposed Pole Plate Magnets,Tramp Metal Magnet,Magnetic Plate with Raised Poles,Raised / Exposed Pole SurfacePlate Magnet,Tramp Magnets Exposed Pole Plate Magnet are designed for removing tramp metals from the low volume materials flow. They will be installed below the materials flow in the process line.Exposed Pole Magnet recommended for placing beneath 
Flush Face Plate Magnets, Smooth Face Plate Magnet,Flush Face Magnetic Plate,Magnetic Plate Separator,Conveyor Magnet, Flat Face Plate Magnets, Magnetic Sheet Separator Flush Face Plate Magnets have ideal metal sepration performance when assembled over the flow chute or belt applications with low-density product flows. Downstream processing facilities will be under continuous magnetic protection because plate magnets 
A) Gauss readings using a gaussmeter. Gaussmeters measure the number of lines of flux in a magnetic field. This is an accurate measurement of the magnetic field but is an expensive piece of equipment. One of the drawbacks is that the sensitivity of the gauss-meter will produce different results with the slightest movement. When monitoring the performance of a magnetic separator over a period of time, accurate comparisons will be very difficult.
B) Pull tests are the most common method. This requires a pull test scale ( spring loaded scale graduated in ounces or pounds ) and various test fixtures. When comparing test results, whether between different magnet manufacturers or an in-house scheduled audit, it is imperative that the same procedure and apparatus are used in each test. If a smaller ferrous test fixture is used than what was used in the previous test, the results will differ greatly. The reason for this is the larger the ferrous test fixture, more of the magnetic field will be absorbed, therefore, producing higher test results.
Pull tests produce two end results- pulling power and holding power. Both of these results are of equal importance. Pulling power relates to the "reachout" of the magnetic field. Depending on the application, a magnet that has the power to draw ferrous contaminants out of a product stream should have the ability to retain that ferrous contaminant. Therefore in comparison the reach out would be more critical than the holding power. Plate magnets typically fall into this category.
Holding power relates to the breakaway force required to remove the ferrous test fixture from the working surface of the magnet. Grates and drawer type magnets typically have 1" diameter magnetic tubes mounted on 2" centers. Quite often there are two or more rows of staggered tubes. While reach out is still important, it is more critical to the performance of the separator that it have the maximum achievable holding power. The staggered configuration of the magnetic tubes causes the product to cascade over one row of tubes and fall directly below on top of the following row of tubes. This ensures the weakly magnetic particles will be captured and retained and not return to the cleaned product.