Metallic particles can enter the production process through raw materials, wear on machines, tools or components that come loose during operation.

Even when they are small and difficult to perceive, these particles can reach equipment, remain in the final product and compromise the quality of the processed material.

Magnetic grids are used to retain ferrous contaminants during the passage of granulated or powdered products. Installed at strategic points along the line, they increase the material's contact with magnetic surfaces and help prevent particles from advancing to more sensitive stages.

What are magnetic grids?

Magnetic grids are static equipment formed by one or more rows of magnetic bars or tubes organized within a structure.

During the passage of the product, these bars attract and retain the ferrous particles present in the material.

The grilles can be installed in free passages or internally in ducts. When located inside a duct, their structure may have side handles or a drawer-type system to facilitate removal and cleaning.

This configuration can be applied to materials such as:

• Sugar;
• Flours;
• Grains;
• Plastics;
• Ceramics;
• Minerals;
• Pigments;
• Food products;
• Granulated raw materials;
• Powder materials.

The definition of the model depends on the characteristics of the product, the flow and the level of retention required.

How do magnetic grids work?

In gravity applications, the material crosses the grid and passes close to the magnetic bars.

Ferrous contaminants are attracted to the surface of the pipes and remain retained until cleaning.

Some configurations have dispersers responsible for directing the product and preventing it from passing through regions far from the magnetic field. In grids with more than one row, the arrangement of the bars can cause the material to follow a zigzag path, increasing contact with the retention surfaces.

This operation makes grates especially useful in processes in which the product flows by gravity within:

• Ducts;
• Funnels;
• Silos;
• Gutters;
• Unloading points;
• Power systems;
• Machine inputs;
• Steps prior to packaging.

What is the difference between magnetic bars and grids?

The magnetic bar is the component responsible for generating the field and attracting ferrous contaminants.

The grid brings together several bars in a single structure, creating different retention points along the passage of the material.

While a bar can be used individually in specific applications, the grid offers a larger contact area and directs the product so that it passes close to more magnetic surfaces.

This configuration can be advantageous when:

• The flow occupies the entire width of the duct;
• There is a large volume of material;
• The particles are distributed throughout the product;
• It is necessary to increase contact with the magnetic field;
• The operation seeks to reinforce contamination control.

The quantity and arrangement of bars must be defined according to the needs of the process.

Why install magnetic grilles in ducts?

Pipelines are strategic points because they concentrate the passage of material between different stages of production.

By installing the grate directly in this flow, the operation can perform retention without depending on an external stage.

Among the main advantages are:

• Taking advantage of the product’s own movement;
• Installation at specific points on the line;
• Greater contact between the material and the bars;
• Retention before more sensitive equipment;
• Lower risk of particles advancing through the process;
• Possibility of integration into the existing structure.

The installation must allow equipment to be removed for cleaning and inspection. Therefore, drawer-type systems can facilitate access to the bars without requiring major disassembly.

Simple grids or with more than one row?

The number of rows influences the path taken by the material.

Single row grid

It can be recommended for processes with a lower level of contamination or when there is little space available for installation.

The material passes through a single layer of magnetic bars.

Grid with two or more rows

It offers different points of contact during the passage.

The bars can be positioned alternately, forcing the product to change direction and move closer to the magnetic surfaces.

This configuration may be recommended when the process requires tighter control or when particles are small and difficult to capture.

The choice must consider the flow, the available space and the ease required for cleaning.

Ferrite or neodymium: which magnet to use?

Grids can be constructed with different types of permanent magnets.

Ferrite models can meet industrial applications with less demanding conditions. Neodymium magnets, also known as rare earth magnets, offer greater magnetic intensity and can be recommended for retaining smaller particles or applications with more rigorous standards.

The choice must consider:

• Type of contaminant;
• Particle size;
• Distance between the material and the bar;
• Working temperature;
• Product characteristics;
• Retention requirement;
• Environmental conditions.

In special applications, other magnetic materials can also be evaluated.

What should be analyzed before installation?

The efficiency of the grid depends on the correct dimensioning and its integration into the process.

Before choosing, it is important to analyze:

Product type

Dry, free-flowing materials behave differently than wet, sticky or clumpy products.

Granulometry

The size of the particles influences the way the product passes between the bars and the risk of clogging.

Flow

The grid must allow the necessary volume to pass without compromising the pace of production.

Duct dimensions

The structure must be compatible with the shape and size of the installation point. The grids can take on square, rectangular, elliptical shapes or adapted to the system geometry.

Temperature

The temperature of the product and the environment must be considered when choosing magnets and construction materials.

Cleaning frequency

The greater the amount of contaminants, the shorter the interval between cleanings should be.

Does cleaning interfere with efficiency?

Yes. As particles accumulate on the bars, they create a layer over the magnetic surface.

When this accumulation becomes excessive, new contaminants may find less space to adhere, reducing retention efficiency.

Therefore, it is necessary to establish a cleaning routine based on actual process conditions.

The frequency may vary according to:

• Quantity of particles found;
• Volume processed;
• Number of hours of operation;
• Product type;
• Level of control required.

During cleaning, it is also important to prevent the removed contaminants from falling back into the duct or returning to the material.

How do you know if the grid is suitable for operation?

Some signs may indicate that the equipment or routine used needs review:

• Metallic particles found after the grid;
• Accumulates very quickly in the bars;
• Difficulty in passing the product;
• Frequent obstructions;
• Excessive need for cleaning;
• Grid incompatible with duct dimensions;
• Changes in the volume or type of material processed.

The operation must also be reevaluated when there is an increase in production, a change in raw material or a change in the required quality standard.

Strengthen control of ferrous contamination

Magnetic grids create a retention barrier directly in the material flow.

By bringing different bars together in the same structure, they increase contact points and help prevent ferrous particles from entering machines or remaining in the final product.

To achieve the expected performance, it is necessary to consider the type of material, flow rate, duct shape, contamination level and cleaning frequency.

ITAL develops magnetic grids in different dimensions, formats and configurations, according to the characteristics of each industrial application.

Contact the technical team and find the right solution for your production line.

Talk to ITAL

WhatsApp: (11) 96416-4821