A well-oiled operation
It’s time to rethink relubrication. Thanks to an innovation from SKF, a leading snack food producer is using fryer oil to lubricate the bearings in its commercial fryers, allowing for safe operation for up to 16,000 hours without the need for relubrication or unplanned stoppages.
The inside of a commercial fryer is an incredibly hostile environment for machine components. Bearings, for example, are subject to regular splashing by extremely hot oil for long periods of time, which can eventually cause sealing material to break down and allow contaminants to enter the arrangement’s inner envelope as well as the food-production area. There is also the issue of the cleaning operation: Every week or so, fryers must be drained and undergo a boil-out procedure with caustic-based fluids, during which some lubricant is inadvertently washed away, potentially into the food-processing area. This necessitates time-consuming relubrication with high-cost, high-temperature lubricants after each cleaning.
Bearing the burden
Even if bearings are cared for in this way, the severe operating conditions of fryers limit bearing service life to around 3,000 operating hours – or a service life of around three to six months. During this time, it is imperative that the condition of bearings and seals is monitored closely, as failure can lead to catastrophic outcomes. A fryer containing hot oil cannot just be switched off and repaired. Unplanned maintenance takes the equipment out of service for at least 24 hours and negatively impacts productivity. Operators and engineers have to take responsibility to ensure sealing and bearing integrity.
If a bearing becomes damaged it can leak lubricating grease, and pieces of the bearing itself can spill out into the fryer. With a failure of this type the oil must be drained and then strained and possibly even replaced to recover any wayward material. There is also the issue of contamination of the product. Food recalls and standards are on the rise, and any incident like this could render a product unfit for the market. The company suffers in terms of not only money and productivity but also reputation.
We reduced planned and unplanned downtime, providing better line availability and reduced costs – both by eliminating relubrication and associated costs and because fewer replacement bearing units are needed.
Global portfolio development manager, Food and Beverage, SKF
Cooking up a solution
To help food and beverage stakeholders – specifically operators of commercial fryers – combat these challenges, SKF engineers have developed a unique solution that facilitates a symbiotic relationship between the fryer and the bearing itself.
SKF’s team of experts concluded that fryer bearings’ load and speed requirements were low enough that the cooking oil itself could provide the necessary lubrication, so they set about developing a bearing with characteristics that allowed reliable operation despite the extreme temperatures and aggressive chemicals found in the customer’s equipment. The solution was a high-temperature plastic cage, specially designed to perform well in poorly lubricated environments with stainless steel rings and rolling elements.
The innovative SKF fryer bearings required no relubrication and met materials requirements for food and beverage manufacturing in corrosive environments. As a result, the snack food producer can use the same bearing for up to 17,500 hours – significantly increasing the existing bearing’s lifespan and eradicating unplanned stoppages.
By eliminating the requirement to regrease, SKF fryer bearings massively reduce the time and costs associated with relubrication. The customer also chose to push the new SKF technology to its limits to establish a new baseline for the life of its fryer bearings. Now, the bearings are carefully inspected during each planned maintenance period. Only when the bearing assembly shows increased wear do the engineers take action.
In addition to reducing maintenance requirements and costs and vastly reducing the risk of catastrophic bearing failure, SKF’s relubrication-free bearings also produce a smaller environmental footprint than traditional bearings. No lubricating grease is released into the environment, nor is replacement grease required. In addition, the far longer lifespan of the SKF bearings cuts the number of bearings sent to recycling by at least half as well as reducing CO2 emissions involved in the production of new bearings.