Methods for repairing paper machine bearings

Bearings are wear-prone components in paper machines. Once they wear out and become ineffective, it is necessary to halt production for replacement, which can cause significant economic losses to the paper mill. Therefore, ensuring the reliable operation of bearings is of great importance for the smooth and continuous functioning of paper machines. This article analyzes methods for online bearing repair. Sanjiu Bearing Network—bearing model inquiry.

In medium- and high-speed paper machines, the most common failure points due to wear and tear are typically the bearings in the wire section, the press section, and the calender—especially those in supercalenders and soft calenders. The reason is that these areas of the paper machine operate under extremely harsh conditions: high loads, elevated temperatures, high humidity, and high speeds. Currently, the lubricants commonly used in paper machines generally lack sufficient anti-wear and water-resistant properties, making it difficult to achieve ideal lubrication. Even when using synthetic lubricants from some internationally renowned brands, it remains challenging to fully meet the demanding operational requirements of high-speed paper machines.

The principle behind using high-performance lubricants to repair bearings is that the most common lubrication condition for bearings is boundary lubrication. Poor bearing lubrication is often caused by insufficient lubricant performance, resulting in a boundary film with low strength and inadequate load-carrying capacity. At high loads, this weak boundary film can rupture, leading to metal-to-metal contact and causing surface roughening and wear marks on the bearing’s working surfaces. As a result, the bearing experiences abnormal temperature rise and increased vibration. At this point, the wear rate accelerates dramatically, and the bearing quickly fails. In contrast, high-performance lubricants—thanks to their exceptionally strong boundary films—effectively prevent wear. Moreover, certain composite lubricants with self-repairing capabilities possess a unique micro-polishing effect that can gently polish already roughened bearing surfaces, making them smooth and mirror-like and thus achieving the goal of bearing repair. After being repaired with such lubricants, failed bearings exhibit lower operating temperatures and reduced friction coefficients. Bearing network

The method of online bearing repair for paper machines allows for the in-situ correction of bearings that, when using conventional lubricants, exhibit abnormally high temperatures and excessive vibration requiring shutdown and replacement. By injecting a higher-performance lubricant into the bearing while it remains in operation—without shutting down—the existing lubricant can be gradually displaced. After operating for a certain period, this approach can achieve a noticeable corrective effect, restoring the bearing’s temperature and vibration levels to normal. As a result, the paper machine can continue operating until its scheduled major overhaul, at which point the old lubricant can be completely removed and replaced without needing to replace the bearing itself. Currently, high-performance lubricants with corrective capabilities have already become available—for example, the Zircron synthetic lubricant produced by the U.S. Zircron Corporation. Online repair of failed paper machine bearings not only reduces unscheduled downtime and prevents substantial economic losses but also significantly cuts down on maintenance costs and expenses associated with bearing replacement.

There are numerous examples, both domestically and internationally across various industries, of successfully repairing bearings by using high-performance composite lubricants. The following are several typical cases analyzed in this article.