The No.1 lubrication-related mechanical issue is bearing failures due to frequent wash down and ingress from aggressive cleaning chemicals.
Let’s face it - aggressive cleaning regimes are critical to keeping the plant free from pathogens.
Unfortunately these are often not carried out in a manner that is conducive to good maintenance. This leads to high pressure wash-down and ingress into bearings - both sealed-for-life and regreasable bearings.
There are a range of simple to implement strategies that can have a significant impact on bearing life, sometimes as much as 10 times:
1. Firstly always ensure that all motors are bagged up.
2. Ensure bearing end covers are fitted to protect from direct attack from washdown (this is also a potential H&S issue to protect operators from rotating shafts)
3. Establish a correct condition based (rather than time based) relubrication regime, this can be simply and effectively achieved through the use of low cost, (less than £700) hand held UE equipment.
4. Always use a chemical resistant grease. Many greases claim a reasonable degree of water washout resistance, unfortunately the key issue here is the aggressive cleaning chemicals, such as sodium hydroxide, and surfactants that are designed to effectively degrease! These tend to “creep” into the bearings as they cool down following use and most of the seals found on bearings are little more than “dust covers” and will not be able to resist either the pressure of the water or the foams used.
Having established the correct relubrication regime there are still a number of alternative options that can be considered:
1. Consider using single point lubricators, these effective devices can be mounted either directly onto the housing or mounted remotely and piped up to 1.5M. They rely on a low pressure (75psi) and can be piped up with standard airline fitting. They keep the bearing under positive pressure and will not overlubricate and potentially cause damage to the seals.
2. A standard industrial grease gun will deliver between 10,000 and 15,000 psi, which is more than 10 times the force required to damage a bearing.
3. Once the correct relubrication regime has been accurately determined when you are using a chemical resistant grease you might want to consider piping the grease point out so that it can be lubricated whilst the bearing is running (this is the best way to lubricate as it does not rely on the equipment being off-line).
4. Consider the use of alternative bearings with water resistant seals. SKF Foodline Y bearings have an extremely effective design that guarantees prevention of chemical ingress from water pressures up to 100 Bar.