The importance of greasing bearings while they are in motion, rather than when they are immobile, is often not understood, or is overlooked, says Delta Sales International, distributor of single point lubricator GreaseMax.

A moving bearing, the company explains, has less resistance to grease input, and slow and progressive input at low pressure into a moving bearing “allows the grease to be taken up into the moving bearing elements”.

“Grease added slowly and regularly will provide continuous purging of grease that has reached the end of its useful life. Thus, older grease is prevented from remaining in the bearing long enough to become depleted or contaminated, or worse, to harden, and become a lubrication maintenance problem,” the company elaborates.

It explains that by correctly lubricating a bearing in this manner, it will also mean a reduced grease requirement as the grease is more efficiently used.

“The actual amount of grease needed to lubricate the contact surfaces is quite small. However, to achieve this better efficiency the grease must be introduced slowly and continuously. Lower grease use results in less contamination clean up and it’s better for both the environment and costs,” Delta International Sales comments.

The benefit of lubricating bearings slowly and continuously, when they are moving, can be measured in terms of reduced failures and productivity increases, the company advises, noting that GreaseMax lubricators provide an “effective and proven method” of reliably providing continuous lubrication in all industries and operating environments

The company comments, however, that even if the importance of greasing bearings when they are moving is understood, it is often not implemented owing to practical constraints in terms of moving machinery or occupational health and safety regulations.

“Grease is typically pumped in by a high-pressure grease gun or lube system at a higher than necessary volume, in a short time period. It is hoped that the new grease will make it into the bearing and remove the older grease,” the company explains, noting that some of the grease may enter the bearing.

However, the company warns that if there is any sort of constraint to its entry, “it quite possibly may instead simply pass out the closest seal” as the older grease in the bearing will tend to block the entry of new grease.

Considering that this older grease is likely to be on the peripheries of the rolling surfaces, and not on the areas of contact where lubrication is needed, it means that the older grease remains.

Not only is it limited as a lubricant owing to a possible oil or additive-depletion, it could also be contaminated or oxidized, Delta International Sales says, stressing that the presence of this impedes the entry of new grease into the rolling elements, thereby exacerbating existing issues.