Using Ultrasound Techniques to Assess the Greasing of Bearings

The best practice for greasing bearings is using ultrasound, as this helps determine how much grease is required. Ultrasound is an effective method of measuring friction – increased friction levels can be caused by applying too much or too little grease to a bearing.

By using ultrasound, the correct amount of grease can be calculated by evaluating the required levels. SDT LUBExpert ensures that the correct amount of grease is applied for each bearing using ultrasound and condition-based lubrication.

In addition, the Ultranalysis® Suite 3 software provides a way of saving valuable lubrication data, traceability, and trending where grease replenishment quantity, intervals, and ultrasound levels are recorded.

The information archived in this database can also be used to improve lubrication intervals/schedules, as well as to analyze root cause failure.

The LUBExpert also allows for the screening of bearing conditions by utilizing the ultrasound crest factor algorithm.

Several trials on a large amount of grease-lubricated bearings across various plants were conducted. These bearings had been previously greased using fixed replenishment rates calculated from grease application calculators and/or formulas.

Results

In one example, LUBExpert was used to inspect the bearings to determine the correct quantity of grease. The study indicated that approximately:

70% of bearings were over lubricated,

15% of bearings were under lubricated, and,

15% of bearings had the correct replenishment rate.

The results from this trial are similar to results recorded from other plants.

Conclusion

Rather than relying on calculated/fixed grease quantities, the bearing lubrication is specific to the conditions of each bearing.

Greasing using ultrasound:

Increases the availability and reliability of equipment by ensuring bearings have the correct amount of grease applied;

Allows for further optimization of reliability programs and lubrication schedules, thanks to the data recorded and archived in the lubrication database;

Decreases the amount of grease used and optimizes schedules, which in turn reduces costs.

This information has been sourced, reviewed and adapted from materials provided by SDT Ultrasound Solutions.