Lubricants are the life-blood of any industrial plant, maximising the operational lifespan of production equipment and machinery and minimising the risk of downtime.
However, in food manufacturing facilities, an additional challenge is posed by the requirement to utilise food-grade lubrication over traditional greases and oils, which are potentially dangerous if ingested. John Chappell, managing director of AVT Reliability, looks at how production efficiency need not be compromised by the requirement to use food-grade lubricants – and how an effective lubrication management programme can assist in the general maintenance of a healthy plant.
In any manufacturing environment, lubricants, greases and other fluids are used to lubricate moving parts in equipment – which may be anything from pumps and gearboxes to chain and conveyor belts – facilitating smooth movement and preventing wear and friction. Machinery in food manufacturing facilities in particular is also subject to a wide range of operational challenges which, when coupled with the need to utilise food-grade lubrication, further complicate the selection and management of lubricants. Extremes of temperature, from the highs needed for baking and cooking to the lows needed for refrigeration and freezing, both influence lubricant choice and usually result in a range of products being required for different production areas. Production areas can be dusty, due to the presence of ingredients like flour and powders, or humid in areas where sterilisation or boiling occur. Additionally, food production machinery is cleaned far more frequently than other equipment – meaning lubricant can be washed away – and it may be prudent to modify the wash down process, or use a deflector to keep water away from lubricated areas, in order to prevent almost daily re-lubrication.
The demands of modern production can also influence the products chosen for equipment lubrication. In order to hit increasing targets, manufacturers may be required to run lines for longer periods each day – or invest in new technologies which work at a higher velocity and may therefore have different lubrication needs to older models.
Even in a food manufacturing facility, however, food-grade lubricant may not be required throughout the premises. Hazard Analysis and Critical Control Points, or HACCP, is typically used as a risk management tool, helping lubrication engineers to review potential lubrication leak points. Where these are identified, the machinery or line in question will certainly need to utilise food-grade oil or grease – however many manufacturers now take the view that as lubricant could be accidentally mixed in stores, or unintentionally used on the wrong equipment, the whole factory should use food-grade lubrication to eradicate this risk factor.
The overriding selection criterion for food-grade lubricants should be the product’s compliance with relevant legislation and standards.
Lubrication manufacturers themselves are governed by ISO 21469, which proves that food-grade lubricants have been manufactured in a hygienic environment, using suitable ingredients and with no chance of contamination from foreign bodies which could affect both the performance of the lubricant, and its suitability for food production lines. However, it remains the responsibility of the manufacturer to select an appropriate lubricant and to use it in a manner which maintains its food-grade rating – for example storing food-grade and non food-grade products separately and using colour-coding for easy identification.
The National Sanitation Foundation (NSF) offers various accreditations for different types of lubricants. While products are not tested for compliance, it remains a useful scheme for judging the suitability of lubricants and forms a basis for further investigation of the product’s attributes. H1 is the NSF accreditation for food-grade lubricants, with products carrying this mark deemed safe for ‘incidental contact’, where it is possible that lubricant may come into contact with food products in low concentrations. H2 lubricants are classified by NSF as only suitable for zero-contact applications, and would normally be used outside of the food production area, while H3 is an important accreditation which covers lubricants that have to come into contact with food to function effectively. Products in this category include release agents which prevent food from adhering to surfaces during processing, for example linings for baking pans or greases for other surfaces such as grills.
It is also incumbent upon the manufacturer to ensure that the way in which lubricant is used, does not hamper its food-grade status. As well as implementing correct storage and safety measures to minimise risk of cross-contamination, the cleanliness of the oil once applied to the machine must be monitored. Operational contamination can come from within machinery, such as corrosive metal particles, or indeed the food products themselves – sharp salt and sugar crystals, for example – can also cause physical or chemical damage to component surfaces, especially if poorly lubricated to begin with. Many manufacturers rely on scheduled lubrication and filtration schedules which may not always be suitable for the machine or food products in question. This practice may mean that oil is thrown away when it could be made serviceable again if treated appropriately, or that overused lubricants are left in use for too long. By not carrying out regular analysis of lubrication, particularly if the usage patterns of equipment fluctuate according to demand, manufacturers may be failing to identify potential risk factors that could cause future problems.
While suitable and timely lubrication of equipment in any food manufacturing facility is vital in optimising performance and ensuring safety, lubrication analysis can actually give an insight into the operational health of plant equipment.
There is no doubt that a well-implemented lubrication management programme will improve equipment reliability in the same way that a healthy lifestyle keeps us fit. Given the critical nature of lubricants and the frequency with which mechanical failure is related to the lubricating system, effective lubrication management is probably the most important single function within any planned asset maintenance programme, especially when combined with other practices such as alignment, condition monitoring and filtration.
Structured testing and reporting is an important part of the process, especially where there may be hundreds or thousands of measurement points around the plant. If an item of rotating equipment fails, for instance, the cause of the problem is often attributed to a bearing failure. The bearing failure is however a symptom rather than a cause and by simply replacing without looking into why it failed, similar problems will almost certainly continue to occur. An integrated maintenance solution applied to a rotating equipment system, comprising effective lubrication, condition monitoring and contamination control, will deliver significant improvement in equipment reliability.
Outsourcing lubrication management and tribology as part of a wider condition monitoring programme has a number of very cost-effective benefits. AVT provides customers with maintenance optimisation and equipment reliability improvement services. Its engineers are maintenance surveillance engineers applying valuable maintenance methods such as vibration analysis, thermography, lubrication, and filtration management. All these core competencies are applied by skilled engineers who truly understand the importance of such techniques in maintaining and improving equipment reliability.
However, more importantly, they are maintenance practitioners who have an in-depth understanding of the equipment they are maintaining and therefore have a deep appreciation of the impact the above key methods have on equipment performance.
In summary, high performance lubricants will provide measurable benefits provided they are well-managed and maintained, and applied by skilled maintenance practitioners. Lubrication resource optimisation, which includes other key maintenance techniques such as vibration analysis and contamination control, is proven to enhance equipment performance. In parallel, good filtration management (contamination control) will enhance the life of equipment and oil significantly – as well as ensuring adherence with food safety and maintenance standards.