To explain why over-greasing bearings can be troublesome, BSC Agriculture, Food and Beverage Manager, Chris Wheatley, resorts to a donut analogy: “There’s only a certain amount of jam you can fill into a donut before jam oozes out from the other end. Similarly, if you over-grease a bearing, the seals can dislodge allowing contamination into the bearing. High operating temperatures can also occur with a high volume of grease. Too much grease in the bearing cavity will cause the rotating bearing elements to build pressure and begin churning the grease. This will lead to oxidation, which is separation of the oil from the thickener.”
And while modestly filled donuts can be a disappointment, under-greased bearings can have the same life-shortening effect as over-greasing, as Chris further explains. “Bearings that are under-greased tend to heat up quickly too when there is no lubrication film between the rolling elements. The metal-to-metal contact will shorten the service life considerably.”
Maintaining the optimum amount of grease in bearings was something that a CBC Regency Park branch customer, a major independent brewer in Adelaide, was looking to eliminate from their maintenance routine altogether.
“This is a large plant, and they have multiple conveyors running in their bottling line,” says Chris. “Bearings in these conveyors were failing frequently and the maintenance team was looking at a solution that would extend the bearing life with minimal maintenance requirement.”
The CBC Regency Park branch has been supporting the brewery with all of its bearing and power transmission requirements for over 20 years. So, when Andrew Fant, CBC’s Major Accounts Executive, recommended that the brewery switch to the NSK Molded-OilTM bearings for their bottling conveyors, they accepted the solution right away.
Molded-Oil bearings are a class of bearings from NSK that do not require any greasing. The bearings are lubricated for life with Molded-Oil, NSK’s own oil-impregnated material which is made with lubricating oil and polyolefin resin. As the bearing rotates and heats up, oil slowly seeps from the Molded-Oil and keeps
the bearing lubricated for an extended period of time.
With the bottling process involving heavy water washdown to clean the bottles, Andrew recommended stainless steel NSK spherical roller bearings with Molded-Oil for the application.
Since taking the solution on board in 2018, Chris says the plant has not experienced any abrupt bearing failures.
“As each conveyor bearing fails, the maintenance team replaces it with the equivalent Molded-Oil stainless steel bearing. Since starting the program in 2018, they have checked the bearings every time they had a scheduled maintenance shutdown but the NSK bearings have not required replacement. CBC keeps a record of bearings sold to each customer and this particular plant’s order for new bearings has reduced drastically since switching to Molded-Oil,” says Chris.
Apart from saving on bearing costs,
Chris says as a bonus, the plant has also been saving on the personnel hours required for greasing the bearings and the cost of the grease.
“This is where the benefits of the NSK Molded-Oil bearing really come to the forefront. These bearings have an excellent performance in water and dust contaminated environments, and they are designed to prevent liquids from washing the lubricating oil out of the bearing.”
Despite the many benefits that solid grease bearings like the NSK Molded-Oil offer in the food and beverage processing plants, Chris says there are still many
who hesitate from using them purely due to cost.
“The mistake that many people make is that they look at the initial cost of the bearings and they don’t consider the life-time savings. But if you are extending your bearings’ service life and your maintenance team no longer needs to worry about checking and greasing the bearings regularly, it’s definitely worth considering whether or not the solid grease bearing is the right solution for your plant,” says Chris.
“All CBC staff are trained by the NSK team on the features and benefits of their bearings and we have experienced engineers like Andrew Fant who lend their knowledge and expertise to some of the biggest food and beverage manufacturers in Australia. We share that knowledge when we visit any industrial plant, like the case of this brewery.”