Hygienic and Safe: Rolling Bearings for the Food Industry

In the food and beverage industry, the reliability of machine components and their hygienic quality play a crucial role. Rolling bearings used in this sensitive area must satisfy special requirements in order to meet the strict hygiene standards and safety regulations. The protective measures involved are two-pronged: On the one hand, it is necessary for the bearings to be designed so that they will not be damaged during the processing of food and subsequent cleaning with high pressure, steam and chemicals. On the other, the machine components must be prevented from contaminating the food with any grease, rust or dirt.

In this article, we explain how manufacturers comply with these special requirements in the further development of their rolling bearings and which technologies are used to do so. We also present the different designations and characteristics of the manufacturers’ products.

Requirements for Rolling Bearings in the Food Industry

The bearings need to be adapted to handle the different environments involved in the particular application. For this reason, bearing manufacturers offer various designs and options for their products. For instance, the components may have to withstand permanently wet or moist environments, high pressures, very hot or cold temperatures or corrosive liquids. It is therefore necessary for the bearings to meet the following criteria:

1. Corrosion-Resistant Materials: When used in moist environments, it is particularly important for the bearings to be made of a corrosion-resistant material such as stainless steel (e.g., AISI 440C or AISI 316) or plastic to prevent any rust from forming.
2. Food-Grade Lubricants: The lubricants employed need to be approved for at least occasional contact with foodstuffs. NSF H1-certified lubricants fulfil this requirement and are also formulated to be taste-neutral and non-toxic. If the bearing may come into frequent contact with food, it is advisable to choose a lubricant with an even higher food safety rating, such as NSF H3, where NSF stands for the National Sanitation Foundation. A few food manufacturers also specialise in certifications like “kosher” or “halal”, which confirm that the materials and lubricants used comply with certain religious standards. These quality seals mean that the bearings have not been lubricated with greases or lubricants derived from animals but instead use food-safe and allergen-free lubricants that are either of vegetable or synthetic origin.
3. Sealing: The bearings are often fully sealed to prevent lubricants from escaping or impurities from penetrating the bearing. The seals used must be temperature-stable, chemically resistant in order to withstand aggressive cleaning agents and made of food-grade materials. Click here to find out more about seals.
4. Easy-to-Clean Design: The bearings need to be designed so that they are easy to clean and able to withstand high pressure, such as from high-pressure cleaners. It is also essential that they are resistant to cleaning agents and disinfectants. Fully sealed bearings are easier to clean effectively.
5. Temperature Resistance: If the bearing is to be used in either very hot environments, such as an industrial furnace, or very cold environments, such as a cold room, it is essential to select a type that is suitable for the particular operating temperature concerned. Temperature-resistant materials and lubricants are crucial in such situations.

Food-Safe Products in the PICARD Range

Our range includes an extensive selection of products that are especially well-suited to the food industry, including:

• Deep groove ball bearings (open, covered or sealed) from FAG and SKF
• Ball bushings from INA and Bosch Rexroth
• Radial insert ball bearings, housings, housing units and covers from FAG, SKF, SNR and ZEN

Manufacturer-Specific Aspects?

The product designations vary depending on the manufacturer and the product category.

For example, you can identify suitable ball bushings for the food industry by the suffix “NR” at Bosch Rexroth and by the suffix “RROC” at INA (Schaeffler).

Other important designations are found below.

Deep Groove Ball Bearings?

Radial Insert Ball Bearings, Housings, Housing Units and Covers

The product characteristics of radial insert ball bearings, housings (housing units) and covers are designated using different prefixes and suffixes depending on the manufacturer:

• Schaeffler (FAG): The suffix “TV” indicates plastic housings, while “VA” refers to stainless steel bearings. The suffix “FD” is important for the food industry, as it indicates that the bearing has been lubricated with food-grade grease.
• SKF: The “Food-Line” offers bearings specially developed for the food industry. The first part of the designation indicates the design, followed by the housing material: “C” stands for a composite material suitable for food and “SS” for stainless steel. With radial insert ball bearings, the suffix “SS” likewise indicates stainless steel components, while “ZM” identifies galvanised inner and outer rings, threaded pins made of stainless steel and seals and flanges that feature stainless steel inserts. In addition, their seals also have food-grade rubber lips and lubricant. “DFH” (“Designed For Hygiene”) designates a completely sealed housing unit with a cover.
• ZEN: The housings are made of either plastic (“T” for thermoplastic) or stainless steel (“S”) as indicated in the designation prefix. The type of lubrication is specified in the suffix, and bearings suitable for foodstuffs have the suffix “FDA” or “GA351”.
• SNR: All SNR bearings made of corrosion-resistant stainless steel are food-safe, regardless of which lubricant is designated. The prefix “S” indicates that the housing is made of stainless steel. According to the manufacturer, radial insert ball bearings with the designation “SUC” are designed for stainless steel housings. Information on whether the selected SNR product is suitable for the food industry can also be found in the product properties in our online shop.

Rolling Bearings with Solid Lubricant – An Innovation in Food Technology?

Manufacturers such as SKF, Schaeffler (FAG) and NTN offer rolling bearings with a special food-grade polymer lubricating oil: SKF labels them as “Solid-Oil” (W64F), FAG as “LubTect” (LT), NTN as “Solid Lub” (LP09) and SNR as “LubSolid” (LSA). The advantage of these solid lubricants is that the bearings never need to be regreased thanks to their full lubrication, which reduces the maintenance required and extends the service life. At present, however, this remains rather expensive, and availability is often very limited. As such, this type of bearing is not yet very affordable and is by no means standard. Nevertheless, this technology could result in significant innovations in the food industry in years to come.

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