Tube and Grate Magnets

Nippon Magnetics™ tube magnets are ideal for removing magnetic attractive materials from liquids or powders. Common industries include food and chemical processing plants along with other processing facilities. Tube magnets can be installed in small spaces such as outlets of material chutes or dumpers on manufacturing lines.

Since most production lines in food processing industry are made of stainless steel, the question becomes: Will magnets capture stainless contaminates? Austenitic SUS304 and SUS316L are considered non-magnetic materials. However, when some kind of shock, such as cutting, tearing, twisting, shaving, polishing, pressing, welding, friction, or deformation, occurs and stainless becomes magnetic attractive. Contaminates in food lines are typically the result of one of these actions. Nippon Magnetics rare earth magnets provide high strength Gauss up to 15,000 Gauss and can capture these contaminates.

Our rare earth magnets are the heart of our tube and grate magnets and used in multiple industries to remove contaminates and incidental insertion of ferrous fines. Many designs offer a double wall design for easy cleaning.

High Gauss Tube Magnet 15,000 Gauss


Easily installed in narrow spaces such as raw material outlets and outlets in the production line.

Features and Benefits

  1. It can be used in liquid because it is a stainless steel pipe.

  2. We manufacture bar magnets with a maximum surface magnetic force of 15,000 Gauss*.

  3. We can manufacture it in units of 1 mm according to your desired dimensions.

  4. It is also possible to attach an inspection report with magnetic notation for countermeasures such as HACCP and ISO.

  5. Ion nitrite, tungsten spraying, Teflon processing, etc. can be performed on the pipe surface.

  6. With eye bolts, with handles, etc.

*15000 Gauss specifications are nominal values.


  1. Ultra high magnetic force type (15,000, 14,000 Gauss), high magnetic force type (12,000 Gauss), standard type (10,000 Gauss), heat resistant type (10,000 Gauss), ferrite type (φ25, φ32).

  2. Pipe material: SUS304, SUS316L, titanium

  3. Tap processing and male thread processing are also possible*. Standard tap specifications M6, M8 (depth 12 mm)

*Other than standard taps are possible

Micro pitch tube magnet excellent for removing SUS-based contaminate in fine powder

As the size of foreign matter becomes smaller, it becomes more difficult to attract with magnets.

Fine stainless abrasion powder has weak magnetism and cannot be adsorbed unless it approaches the magnetic pole part as much as possible. Therefore, a magnet with many magnetic poles is more effective. Micro pitch tube magnets combine high Gauss strength with close poles making the recovery rate for removing weak magnetic foreign matter much greater.

Features and Benefits

The gap between the poles is narrow and the number of iron powder adsorption sites has increased several times. Effective for removing weak magnetic foreign matter such as SUS powder.


  1. Pipe material: SUS316L

  2. Surface magnetic force: 10000 Gauss or more

Heat resistance temperature 200℃ High magnetic force even in high temperature environments!

The maximum operating temperature of bar magnets called semi-heat resistant bar magnets (Nd type) is usually 120 to 150°C.

The original magnetic force will be restored when the temperature returns to room temperature, but in that environment the magnetic force is lower than expected.

On the other hand, Sm-based heat-resistant bar magnets have the advantage that the decrease in magnetic force is small.

Features and Benefits

  1. Little decrease in magnetic force even in a high temperature environment.

  2. Cost reduction compared to conventional products


  1. Heat-resistant temperature 200℃

  2. Surface magnetic force: φ24.2 specification 11,000 Gauss/φ25 specification 10,000 Gauss

Triangle Magnet - Improves Iron removal efficiency >5%

It is effective for powder raw materials that are easy to deposit, and because the raw materials are hard to deposit on the surface with high magnetic flux density, the iron removal effect is improved.

Triangular bar magnet

Features and Benefits

Effective for powder materials that are easy to deposit


1.7 Tesla tube magnet


Ideal for recovery of weak magnetic materials.


  1. Pipe surface 1.7 Tesla (17,000 Gauss)

  2. Outer diameter size: φ50

World's first square bar magnet for suspension (patented)

The surface magnetic flux density of a bar magnet is high, but since the magnetic flux lines do not extend for a long distance, the magnetic flux density drops sharply a few millimetres away from the surface of the pipe. Therefore, even if a bar magnet was hung low, it would not be effective. Not so with NMI's suspended tube magnet maintains high flux over a greater distance.

We have developed a rectangular bar magnet for suspension that removes fine iron powder by maintaining a high magnetic flux density even if it is hung on a transported object and a certain distance is provided. (Patent No. 5865321)


Weakly magnetic foreign matter is collected by hanging it on a film, foil, paper, etc.

Catch foreign matter by hanging within the range of 1 to 10 mm above the conveyor surface.

Features and Benefits

(1) The product is not damaged because it is removed at a certain distance.

(2) The bar magnet has strong and weak points of magnetic force in the length direction, but the SSB type has a surface magnetic force of 10,000 Gauss (1.0 Tesla) in the length direction, so it collects magnetic foreign matter regardless of where it passes.


  1. Surface magnetic force 10,000 Gauss, 5000 Gauss or more under 5 mm

  2. Pipe material: SUS304

Grate Magnets

Grate magnets serve a number of applications. They can be placed on top of hoppers or vats to capture ferrous materials during the filling process or can be placed at the bottom of hoppers, silos, bins, vats, etc to capture ferrous material as the unit discharges. Grate magnets can be used with wet or dry materials. Various configuration are only limited by your imagination. They can be configured using any of the magnets listed above and nearly any configuration. It is popular to double tube grate magnets to make cleaning easier. Simply pull the inner magnets and the outer tubes are demagnetized and can then be wiped clean.

Grate Magnet in Case


It can be easily cleaned by connecting it with a flange, ferrule, etc., and incorporating it into the production line.

Features and Benefits

  1. It is possible to increase the iron removal rate by assembling in multiple stages (4 stages or more).

  2. Design and manufacture a casing that matches the installation space.

  3. Cleaning can be done more easily by using a double tube magnet.


  1. You can select the type of bar magnet.

  2. Casing material: SUS304, SUS316

  3. Connections other than flanges are possible.

Optional grate type magnet with casing

  • Double tube type

  • Round grid type

  • Vertical grid type

Automated Grate Magnet in Case


It has a double-pipe structure, and uses an air cylinder to automatically pull out the bar magnet and perform cleaning. The automated grate magnet is useful in application where it is not convenient to clean manually or where reducing labor is imperative.


Dedicated control panel included

Rotary magnet


The magnet rotates to collect iron while preventing the material from clogging. We also manufacture ferrule connection type.


  1. 100A, 125A, 150A, 200A, 250A, 300A connection.

  2. You can also specify the number and type of bar magnets.

For connecting rotary magnet 125A (double tube type)

Video Clips

Automated Grate Magnet Video

Rotary Grate Magnet Video