Reliable, efficient machinery com- bined with technology plays a key role in the food processing
industry. Regardless of the industry segment, equipment must be designed to
withstand the rigors and safety constraints
of the food processing industry. Bearings
are critical components in food processing machinery, and decisions made by
designers and engineers — such as
lubrication, material and shielding options
— are integral in the life and performance
of bearings in these applications.
The U.S. food processing sector is
extensively regulated by state and federal
agencies. Federal agencies dominate the
regulatory oversight: USDA FSIS for the
meat and poultry processing businesses
and FDA for all other food processing
businesses. State agencies also have an
active role in overseeing food processing
businesses within their respective states.
All materials used in the food processing process, including the lubricants,
must comply with federal requirements.
And, depending on the application and
products, materials and components such
as bearings used in machinery may even
require USDA/FDA approval.
Lubricant selection is critical to bearing performance and life, yet it is often
overlooked by designers and engineers.
Bearing life in the harsh environments
found in food processing depends on
proper lubrication in terms of both type
and amount. Thousands of greases
and oils are available that are designed
to function in a variety of conditions.
Operating temperature is the primary
consideration when selecting a lubricant.
Temperature directly impacts the base
oil’s viscosity, which in turn impacts the
ability to support loads.
Lubricant selection not only depends on
the operating conditions the bearing will
face, but may also be subject to regula-
tory requirements. Manufacturers of food
processing machinery are often required
to use “food-grade” lubricants. These
lubricant types are broken into categories
based on the likelihood they will contact
food. The USDA created the original food-
grade designations — H1, H2 and H3
— and the designations are described as
H1 lubricants are food-grade lubricants used in food processing environments where there is some possibility of
incidental food contact.
H2 lubricants are lubricants used on
equipment and machine parts in locations
where there is no possibility that the lubricant or lubricated surface contacts food.
H3 lubricants, also known as soluble
or edible oil, are used to clean and prevent rust on hooks, trolleys and similar
Lubricants should provide good wear
and corrosion resistance. Lubricants used
in high-temperature applications such as
meat, poultry, fruit-vegetable and beverage processing should have high-temperature oxidation stability.
Machinery used in beef, pork and
poultry processing is typically exposed
to “wash down” conditions using high-pressure water and anti-bacterial solutions which are often caustic, or steam,
which can displace the grease. To avoid
grease displacement, greases with high
resistance to water washout are used and
fill 70-100% of the bearing (as opposed
to a typical fill amount of ~30%). While
this level of filling can negatively affect
rotational speed, it significantly improves
H1 lubricants used in these environments typically have synthetic, hydrocarbon base oils with urea, polyurea or aluminum complex thickeners. H2 lubricants
typically have mineral or PFPE base oils
with calcium soap or PTFE thickeners.
Bearing Design Considerations
for the Food Industry
By John Wallace, Vice President of Operations, AST Bearings