Five Magnetic Separator Myths, Part Three: Is the Highest Gauss Magnetic Separator Always the Best?

Often, Bunting will receive questions asking if a magnetic separator can be designed in a specific size. This is a simple enough request. However, things become more complicated when the enquiry also requests a specific Gauss value.

It is understandable why customers would inquire about Gauss, as it is frequently quoted by companies supplying magnetic separators. It is also the standard used by HACCP, which is the most widely used program for ensuring food safety. However, customers are not always provided with information about the specific relevance of Gauss. What is Gauss? Is 100,000 Gauss better than 10 Gauss? In this blog, we will answer some of these questions.

“Gauss” is defined as the cgs (centimeter-gram-second) unit of measurement of a magnetic field. This is also known as the “magnetic induction” or “magnetic flux induction.” One gauss is equal to one Maxwell per square centimeter.

Unfortunately, this definition does not necessarily help the customer, and may only add to their confusion. Additionally, this definition does not truly assist the customer in understanding if one magnetic separator is truly stronger than another. It is more effective when customers have set parameters to work within, such as the Food Safety Modernization Act stating food processors are required to have 10,000 Gauss.

There are several inherent problems associated with purchasing a magnetic separator based on the “Gauss” value alone:

1) How can you be certain the magnetic separator you are purchasing truly has the level of Gauss quoted?

2) Do you have a Gauss meter to measure and verify the Gauss yourself? Have you been trained to use this tool? It can be difficult for an untrained person to use a Gauss meter, and can lead to some wild results being obtained. It is important that a plant operator is able to get consistent results in order to avoid the mistake of replacing magnets that are still performing optimally.

3) Different levels of Gauss will be found at various different points on the magnetic separator. Do you know where the highest Gauss reading is located on the magnetic separator?

4) Higher Gauss magnetic separators do not necessarily provide the best metal separation, as the ability of the magnetic separator to capture metal particles is not a function of Gauss alone.

Fortunately, Bunting has answers. There is a quick and simple way to measure and assess magnetic attractive force on magnetic separators such as grate magnets, plate magnets, and tube magnets. By performing this physical test, the “Gauss” reading is at least partially removed from the equation. The process is simple and utilizes one of Bunting’s magnetic pull test kits.

First, record the pull value when the magnetic separator is new, or get the value from your supplier. You can use that number as your baseline as you do your test. This will allow you to compare the percentage loss of pull strength as the same amount of percentage loss for Gauss.

To perform a pull test, use a spring balance with a 6 mm 0.5” steel ball on the end. Place the steel ball on the surface of the magnetic separator. Then, the steel ball will be pulled away and off of the magnetic separator. A reading will be taken on the spring balance—this is the pull force. Then, repeat this test at several different locations on the magnetic separator.

After conducting this test, you will then have a real, meaningful, tangible measurement to guide you. With a magnetic pull test kit, you can conduct this same test on various other magnetic separators, and you will be able to independently confirm which magnetic separator requires the greatest amount of force to extract the steel ball from the magnetic field.

As part of an internal auditing system, this test can be repeated at regular intervals as a way of ensuring the magnetic separator is not losing strength. This is a very simple and very effective method of assessing the magnetic strength of smaller magnetic separators. This method does not need extensive training, and does not require high tech, costly equipment.

If magnetic force is important when requesting the price for a magnetic separator, it is recommended that you do not only state the Gauss level. Rather, you should also ask for the pull force measurement. After receiving the magnetic separator, you can then conduct your own pull test to ensure that the purchased equipment meets the ordered specification.

For more information on magnetic separator strength and pull test kits, contact Bunting today.