When to Switch to Automatic Lubricators

Noria Corporation
Tags: automatic lubrication, greases

"Do you have a recommended checklist before changing over equipment such as motors or air fins from conventional grease lubrication to automatic grease lubricators?"

Here are a few considerations:

1. Verify the amount of grease that should be supplied to the unit on an ongoing basis. This can be estimated by checking that the grease provides sufficient oil viscosity at operating temperature, calculating the volume required per lubrication event (based on element dimensions), calculating the frequency for relubrication and setting the system timer to assure that the volume in the lubricator displaces to provide the right volume over time.

2. Confirm that the supply and pressure-relief piping is free of obstructions. Check that the system does not shake appreciably, and if it does, then arrange for remote (indirect) installation. Make sure the feed lines are short enough with a large enough ID so that the lubricator can overcome whatever line loss may exist. Verify that the selected lubricant can accommodate ambient temperatures in the surrounding area.

3. Instead of removing the manual relubrication work assignment, modify the assignment to require an inspection and verification of effective unit operation, and include a cursory component inspection in the work order.

There are certainly advantages to automatic application when compared to manual application. Theoretically, it is preferable to apply small amounts of grease at short intervals rather than large amounts of grease at long intervals.

With manual application, the trick is to apply as much grease as possible without causing harm due to overgreasing, thereby maximizing the relubrication interval. While this is fine for most grease-lubricated components, there are many applications that may benefit from more frequent application or could be harmed by large application volumes. Of course, you could choose to simply lubricate these components very frequently, but the associated labor cost would likely make the option of automatic lubricators attractive.

To accurately determine which lubricated components would be good candidates for automatic applicators, you must understand the factors that cause a need for frequent relubrication, such as excessive temperature, high speeds and contamination.

Temperature is a perfect example. In high-temperature applications, such as those commonly found in steel mills, some bearings may need to be lubricated every day or even every few hours. While this is an extreme example, it's easy to see that it would require a veritable army of technicians to perform manual relubrication on hundreds of bearings every day, thus making automatic application the preferred method.

Some high-speed applications not only require frequent application, but they also may be damaged by the addition of large volumes of grease, causing overheating or skidding of bearing elements.

In many cases, the largest contributing factor to grease reapplication requirements is contamination. Any application can require very frequent application when contamination is severe, regardless of other factors. These are just some of the primary factors to consider. There may be others such as inaccessibility and limited manpower for lubrication activities.

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