The Conveyor Challenge: Rolling Steady

Conveyors may appear to be a straightforward application, but when it comes to achieving consistently reliable performance, they are anything but predictable. Bearings are among the most mission-critical factors in conveyor performance, requiring careful consideration of operating load and speed for the type of bearings selected for a particular conveyor application.

The Solution: The Right Stuff

The key to a continuously running conveyor starts with the recognition that it is an interdependent system, requiring the right products working together for the situation. Timken engineers specify highly reliable products in key head and tail pulley positions. The choice between a spherical roller bearing or a more cost-effective ball-bearing housed unit should be made based on load and speed conditions, keeping in mind that the right bearing will likely save the greater cost of downtime in the long run.

Since many conveyor operations are exposed to harsh conditions, incorporating a quality seal is almost as important as having the right bearing, and upgrades often are worth the investment. Operators who want to increase conveyor dependability should consider adding an automatic lubrication system to provide a continuous supply of grease.

The Screen Challenge

Vibrating screens among the most demanding applications for antifriction roller bearings. Operating conditions result in high radial loads and high rotational speeds.

In addition, screens generate a lot of vibration on the bearing’s cage and rollers, further increasing operating temperatures. Complicating the matter, operators commonly run screens in inhospitable environments, including extreme temperatures and with heavy contamination exposures.

The Screen Solution

Timken offers a complete line of spherical roller bearings, including the 23 and 33 series. While the 23 series is more common, the 33 series bearings offer higher load capacity, as they maintain the same bearing bore and outside diameter.

Key to the spherical roller bearing design is the one-piece fully machined brass cage. The cage pocket wraps around the roller, providing excellent roller guidance as the rollers rotate in and out of the load zone. The roller end and cage pockets are engineered to promote lubrication flow and reduce operating temperatures.

Timken also offers a line of cylindrical roller bearings (CRB) with a rugged one-piece machined brass cage, designed for the unique conditions in vibrating screens. CRBs provide increased load-carrying capacity and lower temperature generation than traditional spherical roller bearing designs. Additionally, CRBs can have specially designed roller profiles to minimize stress across the roller contact and provide optimal performance.

Lubrication Essentials

A bearing lubricant must perform three basic functions:

1.      Reduce friction and wear by separating adjacent surfaces and limiting metal-to-metal contact.

2.      Transfer heat from the bearing surfaces.

3.      Protect the bearing surfaces from corrosion and dirt contamination.

Proper lubrication and generated film thickness in the raceway and roller-end contacts is vital to lifetime bearing performance, and ultimately the operation of the vibrating screen.

Because improper lubrication and/or abrasive wear will almost certainly reduce the life of the bearings and the screen, selecting the right lubricant and lubrication system are essential to uptime.