Solid-Housed Bearings Defeat Fossilized Dirt

July 10, 2008
Preset clearance, positive locking, and torque confirmation ended installation problems.

Jessica Shapiro
Associate Editor

A bearing change did away with installation problems and cut contamination-related wear for a mineral processor. EaglePicher mines diatomaceous earth for filters, insect control, and dynamite. Processing of the mineral takes 8-ft-diameter blowers rotating at 900 rpm. Two bearings support the 2.9375-in.-diameter shaft on which the blowers mount.

The mildly abrasive material’s microscopic particles were finding their way into the bearing during the on-site assembly of the old bearings. In addition, the bearings sit outside and see a wide variety of weather conditions.

The assembly itself was another issue. The original installation method involved premeasuring the clearance and then tightening the tapered adapter nut in increments, using feeler gages to ensure that the bearing was sufficiently tight to the shaft.

When the bearings on one large blower failed, EaglePicher tried Rexnord ZAF6000 Series Shurlok bearings with auxiliary end caps. The new bearings are solid-housed units that are shipped greased and ready to install with a preset clearance. A positive locking system keeps the mounting tight during operation. A tapered adapter sleeve promotes shaft grip and eliminates shaft damage caused by loose bearings.

A built-in Optical Strain Sensor (OSS) ensures proper in stallation torque. Installers get the bearing as close to zero clearance as possible, then tighten the locknut until the OSS window changes color, indicating they’ve correctly mounted the bearing on the shaft.

The preassembled nature of the bearings helped keep the fine particles of diatomaceous earth from contaminating the bearings. Zseals and auxiliary caps installed with the bearings also help ensure debris-free operation.

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EaglePicher Minerals LLC


Previous bearings used at the EaglePicher plant show operating conditions that include fine, abrasive material and outdoor environment.

Rexnord Spyglass Optical Strain Sensor (OSS) technology changes color when the proper mounting torque is reached.

Fully assembled Rexnord 6000 Series Shurlok bearings slip easily onto the shaft and eliminate on-site assembly that can allow contamination.

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