SKF says it has extended its range of large bearings for roller presses, with a sealed version that prolongs service life in equipment such as high pressure grinding rolls (HPGRs).

Its Explorer spherical roller bearings (SRBs) in the 241 series are now available up to 1,250 mm bore, with this series and sizes commonly used in HPGRs in cement and mining operations.

“Using sealed bearings is the best way to increase mean time between failures,” Daniel Ortega, Product Line Manager for Sealed SRBs at SKF (pictured), says. “It is a long-term investment that increases machine availability and reliability.”

The new version – which is sealed on both sides – offers up to double the lifetime of an open bearing and has shown in tests that it reduces grease consumption by up to 99%, SKF says.

In a HPGR, four large spherical roller bearings are usually used. During a maintenance interval of three months, normally 540 kg of grease is used for certain sizes. With sealed Explorer spherical roller bearings, only 7 kg of grease is needed during the same interval, according to the company, reducing both cost and environmental impact.

In addition, the sealed SRB can be remanufactured twice, which further extends service life. This raises productivity and machine availability while lowering total cost of ownership.

The new bearing has been redesigned to have a higher load-carrying capacity. Bearings with a bore diameter below 1,000 mm have an HNBR seal that is retained by a snap ring. Larger bearings use a G-ECOPUR seal that is bolted to the bearing’s outer ring.

The sealed bearing can be used on its own, or as part of an SKF three-barrier solution.

Roller press bearings often wear out because ineffective sealing leads to lubricant contamination. The sealed bearings overcome this problem – and this delivers several advantages, SKF says:

• First, bearing failure relates to more maintenance interventions, which carries a higher risk of accident and injury and expensive shutdowns;
• The new design also offers a maintenance benefit. Rather than stopping production for preventive maintenance of the bearing, the wear of the roller press roller determines when a service is needed; and
• The bearings are available with short delivery times – even in the largest sizes.