Joyce Laird, contributing editor
For extremely contaminated environments, such as agricultural applications, insert bearings equipped with a 5-lip seal on both sides (fig. 1) can be used. The seal consists of a sheet steel insert with a vulcanized 5-lip contact seal made of a low-friction NBR compound. The steel insert, which protects the seal from solid contaminants, is held in place by a groove in the bearing outer ring. Each seal lip has a different design for sealing performance in response to different operating conditions, including dynamic misalignment. The outermost and innermost lips act as a labyrinth to prevent contaminant ingress and grease leakage. The three inner lips make constant contact with the inner ring shoulder.
Food and Beverage Industry
Bearing inserts made of stainless steel or ZMaRC-coated rings and housings made of composite materials and stainless steel are used in corrosive environments such as those in the food and beverage industry. The inserts have an extended inner ring on both sides and are fitted with a multiple seal.
They are filled with a food-grade grease and can be relubricated through the lubrication hole in the outer ring groove. This lubrication groove is located on the side opposite the locking device. All steel components of these bearings are made of stainless steel, including rings, balls, sheet metal parts of both seals and flingers, and grub screws.stainless steel bearing inserts are available for metric shafts from 20 to 50 mm and for inch shafts from 3/4 to 1-15/16 inches. The dynamic load carrying capacity of a stainless steel bearing is less than that of a same-sized bearing made of
The stainless steel bearing inserts are available for metric shafts from 20 to 50 mm and for inch shafts from 3/4 to 1-15/16-in. The dynamic load carrying capacity of a stainless steel bearing is less than that of a same-sized bearing made of high-grade carbon chromium steel.
Composite pillow block housings can be made of a lightweight thermoplastic composite material (fig. 2). They are designed to resist a wide range of chemicals and other treatments used during washdown processes of food and beverage applications. These composite pillow block housings can be used with stainless steel or ZMaRC-coated Y-bearings.
Stainless steel pillow block housings are made of cast austenitic stainless steel (AISI 300 series) (fig. 3). They are designed for more rugged applications to resist a wide range of chemicals and other treatments used during washdown processes of food and beverage applications. Stainless steel pillow block bearing units are particularly well-suited for applications with high speeds, heavy loads and where reliability and minimal maintenance are key factors. Stainless steel pillow block bearing units have a plugged threaded hole to accommodate a relubrication feature when relubrication is required.
High temperature applications
Units for high-temperature applications offer solutions for operating temperatures up to 350 °C (660 °F). They incorporate graphite-based lubrication solutions and have a large bearing internal clearance, which avoids seizing, even when they cool rapidly.
High-temperature bearings are designed for reduced complexity and decreased environmental impact in operating temperatures up to 350 °C (660 °F). Because SKF high-temperature bearings correspond to the ISO dimensions of grease-lubricated bearings, production efficiencies, and cost savings can be realized with a simple change to the SKF bearing solution.