Magnet inspections on location

Why magnet inspections?

Particularly in the food industry, magnet measurements and/or the validation or inspection of magnets is a requirement. Why?

1. To ensure the quality of the finished product.
2. For compliance with HACCP, the international food safety standard.
3. To keep up to date with ever-improving techniques for optimal separation/filtering of metal contaminants.

Does a magnet lose strength over time?

In principle, permanent magnets retain their strength for a lifetime, but there are a few things that could cause permanent degradation of the magnetic strength:

• Heat: Sensitivity varies based on magnet quality; some types of neodymium magnet begin to lose strength at temperatures above 60 °C. The magnetic strength drops to zero once the Curie temperature is reached. The maximum temperature to which the magnetic strength is guaranteed is always listed in our product specifications. Ferrite is the only material that also weakens at low temperatures (below 40 °C).
• Impact: An impact load can alter the structure and direction of the magnetic spins .
• Contact with external magnetic fields.
• Corrosion: The magnet can corrode after damage to the magnet or magnetic coating or when directly exposed to damp air. For this reason the magnets are often built-in and/or protected.

When overloaded, electromagnets can overheat, possibly resulting in corrosion of the coils. This, too, will cause degradation of the magnetic force.

What can you expect?

We check your magnets in the process line annually. In addition to measuring and inspecting the magnetic field strength, we also provide recommendations for process improvements. We document the measurements in an inspection certificate that can be used for audits.

How are the measurements performed?

Our technicians know exactly how and where they must measure, and perform the measurements on-site with a calibrated gauss meter. They take care to interrupt your processes as little as possible and carefully analyse all the installed magnet systems. For Goudsmit magnets, we then compare the measurements with the original values. If the magnet is from another supplier, we compare the measured magnetic strength with that of a similar magnetic separator.

Be sure to also read the blog from our service experts.

What does the inspection certificate show?

The inspection certificate includes the description and location of the measured magnetic separator. The flux density is shown as the measured value, the original value and a minimum value. The minimum flux density is of great importance. After all, the effectiveness of your system depends not on the highest but the lowest value. We compare the data with those from past measurements.

We also provide a report in which we include any recommendations we may have for process optimization. This report contains our evaluation of aspects such as the following:

• Is the magnet placed at the correct (i.e. most effective) location in the process line?
• Does the magnet meet the standard (overall minimum flux density)?
• What is the physical condition of the magnet system?
• Are there signs of wear?
• Is there a risk of obstruction of the product flow or machine damage?
• Is the magnet safely accessible for cleaning?
• Is the deferrization rate (i.e. iron separation) optimal?
• Is the magnet strong enough?
• Is the magnet being cleaned correctly and often enough?

The answers to these practical questions provide insight into the current quality of both the product and the process and can help you improve the process.

Do you have questions or would you like to make an appointment? You can request a magnet inspection via our contact form.

You are also welcome to contact us by phone (040 - 221 32 83) or email () to discuss the options.