Chris Johnson explains the considerations manufacturers must take when choosing bearings and lubrication in the food and beverage industry
When an Aldi supermarket customer recently discovered packs of KP branded Hula Hoops inside a pack of the discount store’s own-brand products, the media was quick to reveal that both products were made in the same place.
Consumers have long speculated that food giants produce both luxury and budget versions of goods for supermarket own-brands, but in the highly-regulated world of food and beverage manufacturing, a simple mistake during packaging is the least of manufacturers’ worries.
Some applications in the food and beverage industry use standard bearings with standard lubricants. However, the closer an application is to the ‘food line’ — the area of a production facility where the food is manufactured and packaged — there more challenges that facilities managers must consider.
One of the notable requirements of bearings in these applications is that the bearing materials should be corrosion resistant.
When operating in these environments, regulations require that bearings are subject to wash-downs or regular steam-cleaning.
What’s more, in some production facilities, these bearings will encounter aggressive cleaning products.
In any industry, choosing the bearing material depends on what is likely to come into contact with the bearing and for food and beverage manufacturing, water and food-grade cleaning products are almost inevitable.
The most commonly used stainless steel for bearings is 440 grade. Bearings made from this grade of steel are often used as they are cost-effective and can cope with heavy loads and high speeds.
While 440 grade stainless steel bearings are corrosion resistant, they can be corroded by caustic and other aggressive cleaners.
For example, in a fish processing facility, the bearings are likely to be exposed to salt water which can cause 440 stainless steel to corrode.
316 grade stainless steel bearings are a more corrosion resistant alternative. These are semi-precision and, as 316 stainless steel is softer than 440 grade, can only withstand low speeds and low loads.
However, they are suitable for low precision applications such as conveyors. 316 stainless steel is known as marine grade steel due to its excellent resistance to salt water.
For food and beverage manufacturers, 316 grade bearings can be the ideal choice, as they are also highly resistant to caustic and other aggressive cleaners.
Where similar corrosion resistance but higher speed and load capabilities are required, zirconia or silicon nitride ceramic bearings offer a third choice.
Zirconia is the lower cost option, but contact with steam will degrade the material over time. Both materials have high corrosion resistance and can be run without lubrication. However, the high cost of these bearings can rule them out for some applications.
Choosing a lubricant
Food grade bearing greases are classified as either H1 or H2 grade. To protect products from any risk of contamination, H1 greases are used where there any risk of incidental contact with food. H1 greases are non-toxic and comply with strict food health and safety regulations concerning base oils, additives and thickeners. They are odourless, tasteless and can even be halal and kosher certified.
H2 greases are used where there is no risk of contact with food, but it is becoming more common to see manufacturers specifying H1 grade lubricants throughout the entire factory.
Food and beverage manufacturers must also consider the grease’s water and chemical resistance as frequent steam-cleaning or wash-downs of equipment with cleaning fluids can remove standard greases.
SMB stock a range of lubricants approved for the food and beverage industry including H1 grade lubricants for use where incidental contact with food is possible.
While packaging errors, like the KP Hula Hoops and Aldi own-brand mix up, might make national news for food and beverage manufacturers, failing to meet regulatory requirements in manufacturing could result in much more damaging fines and loss of reputation.
Choosing the correct bearing and lubrication for each specific application will not only help manufacturers to meet standards regulations, but prolong the lifespan of production equipment.
A little like finding an extra pack of KP Hula Hoops in your discount pack, spending a bit of time considering your bearing requirements will always result in a win-win.
Chris Johnson is managing director of bearing relubrication expert, SMB Bearings.