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Reduce the need and cost of bearing greasing

SKF

For the food and beverage industry, the impact of ineffective forms of lubrication can result in a string of issues from excessive downtime to the costs of continued maintenance and food safety risks.

The lubrication process has also been found to impact on a range of other KPI’s including output of availability, speed and quality as well as health and safety and environmental compliance.

All told, up to 20 per cent of a company’s maintenance budget can be impacted by lubrication.

Eva Otel, SKF global marketing and sustainability – food and beverage, said they identified three key approaches when it came to lubrication and relubrication of manufacturing equipment.

“One of the real bedrocks of plant reliability in food and beverage is lubrication management. What we say is that lubrication management can be impacted in three ways,” Otel said.

This applies across the board from pressure washing hot and cold areas as well as contaminating environments.

Changes in traditional approaches to relubrication of bearings has the capability to impact food safety compliance, cost reduction, asset availability and environmental impacts.

“Basically, the way we started off is that the seven most expensive words in business are, ‘we have always done it this way’, and this very intrenched in food and beverage,” Otel said.

The elimination approach is about trusting new technologies to improve on reliability and safety despite the differences to the traditional approach of lubrication and relubrication.

“Whenever you pressure wash, all of the water and especially the cleaning agent are designed to penetrate, they have a low surface tension that penetrates the seals and this is something that we have learned through a lot of tests that we have done,” said Otel.

“What happens is that these washdowns, the cleaning media gets inside the bearing, the industry knows that water content might be inside the bearing and then what they do is relubricate the purge just to make sure all of that water content has been eliminated from inside the bearing. But very often it’s corroded and sticky with grease.”

Otel said it was understandable for manufactures to be cautious when it came to eliminating the washdown and relubrication process altogether, so several practical studies were conducted for proof of concept.

Meanwhile, the industry standard IP69 safety rating, the ingress protection code for very high levels of protection with regards to enclosures, isn’t enough to guarantee supply line product safety, Otel said.

“What we are trying to say is what are the conditions, bringing some arguments and concrete test results and experience in industry, so having proof points that this works, in order to eliminate that relubrication,” said Otel.

“What we are saying is, is the IP69 rating really a safeguard? Is this belief correct?” said Otel.

“Through the tests that we have done for detergent droplets, they have tested what is happening inside the bearings and the confusion is it isn’t enough, the IP69 rating safeguards against water but not against the detergents, detergents penetrate the seals and come into the grease.

“So you need a different sealing solution than conventionally what most manufacturers use. It’s very logical, the more lips you put in the seal the more protection you give, you don’t allow the water to get inside the bearing but what more lips do is not effective enough.”

Over time the process of relubrication was found to break down the factors constitute a IP69 rating, which in turn can lead to grease being extracted through the washdown, ending up on the floor or in wastewater and causing hazardous risks to worker, environmental and public safety.

“One argument is to have an effective grease that withstands the detergent but also think of a sealing solution which is not based on more lips for the seal. What they have detected is these lips get destroyed with extreme pressure and that is where water comes in,” said Otel.

But research has shown there are improved ways to keep bearings lubricated in cases where old systems are still being used, such as minimisation and optimisation.

SKF have a range of modern sealing options, from internal to external, which have been found to combat the risks of corrosion and grease being extracted during the cleaning process. The gutter seal is one such example.

“When you get the pressure wash the gutter seal will put the lip against the surface and the water is invited inside. Water droplets will penetrate but through the low surface tension and gravity they are guided outside. It is a much better protection to work with the cleaning agent instead of working against it,” said Otel.

Another issue SKF addressed was the use of mounted spacers to combat any lubrication issues.

“They are mounting spacers in the hope that it will give a good hygienic design and better cleanability. It is also something we have proven not to be really true. If there are bacteria inside the bearings it can spread.” said Otel.

“It’s important to have a full enclosure for the bearings if you have high food contamination risks. It is important to have sealability from behind. Otherwise, there would be a gap between the shaft in most conventional solutions, so it is important not to have food residue travel inside the conveyor.

“Additional sealing solutions can be applied, we do have customised seals and they can be machined to whatever the client needs, and they can be done in one or two days with the profiles that are needed by the client.”

If not sealed properly then there is a greater risk of oil leaks which, again, can result in slipping hazards on the factory floor and potential environmental impacts if the oil is caught up in wastewater.

“There are a number of ways sealing solutions can help you keep that lubricant in and contaminants out, so you can have external seals,” said Otel.

“With the right sealing and lubrication technology and the sealability of the insert bearing … you can improve reliability and reduce the change out. You can eliminate the need to relubricate which saves on maintenance and running costs.”

These are just some of the examples of why SKF feels the lubrication processes around manufacturing can be made more effective or eliminated altogether.

SKF used its findings to create the new sealing capabilities to address these issues, and a host of others, centred around the lubrication and re-lubrication of bearings in manufacturing machinery.

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