5 Considerations For Selecting Lubricants In Food Processing
Monday, November 27th, 2017
Food safety awareness has evolved significantly over recent decades, shifting the focus towards the ingredients and processes used to make foods and beverages. To produce quality products that are safe, the lubricants used in machinery throughout food processing facilities are critical. By Michael Davis, brand & marketing specialist; Amy Shifflett, global account manager-refrigeration; and Derek Philips, global director-technical service, CPI Fluid Engineering
The food processing industry has evolved significantly over the past few decades. Shifts in consumer preferences, food safety regulations, and global supply and demand— among other factors—have all contributed to shaping the industry into what it is today. An increasing focus on food and beverage diversity, along with continuing efforts to make food safer for everyone, present unique challenges to food processors in their operations.
Every aspect of the process must be considered for its overall impact on the final product. Running a successful food processing operation requires a balance between quality, efficiency and safety. Selecting the proper lubricant for use in machinery such as pumps, mixers, tanks, hoses and pipes, chain drives, and conveyor belts is critical.
Machinery used in food processing operations has many of the same lubrication needs found in other nonfood processing plants—along with additional challenges. The lubricants must provide protection from heat, wear, friction and deposits, but they must also be engineered with base stocks and additives that are compliant to industry regulations. Contamination of food or beverage products could cost manufacturers considerably in the way of monetary damages, operation downtime and tarnished reputations.
Selecting the proper lubricant for the application becomes quite a challenge. Operational, safety and end-use requirements must all be understood and factored in during the selection process. There are five essential considerations to evaluate when choosing the right lubricant to use in a food processing operation. Several groups within an organisation, such as operations and facility management, should evaluate these factors to maintain the balance between cost, safety and environmental impact.
01 Minimising Potential Risk
Lubricant contamination continues to present major challenges to the food and beverage processing industry. Product recalls prove to be costly to the manufacturer, and can negatively impact their reputation causing consumers to question their products.
The use of food grade lubricants—tested, certified and registered to meet strict performance, health and safety standards—can alleviate the potential risk of contamination.
Eliminating the risk entirely is next to impossible, but understanding the difference between the various classifications of food grade lubricants and additives can aid in the selection process.
In 1998, the USDA terminated their authorisation program for Nonfood Compounds and Proprietary Substances. At that time, the option was given to registered lubricant providers within the industry to either self-certify their products to these classification code standards, or use a third-party registrar for certification. The federal government still allows both methods of certification to be used.
ISO 21469 is an international standard that was developed to go above and beyond the criteria established for the H1 incidental food contact classification. It is a standard that focuses on the hygiene aspect of the manufacturing process, to include the biological, chemical, and physical hazards that are present.
In addition to meeting H1 incidental food contact lubricant criteria, products must also meet several other parameters. Manufacturers must provide documentation to demonstrate that there are operational controls in place to ensure good manufacturing practices.
Moreover, they must prove that there is no cross-contamination in these products, or that the cross-contamination is minimal (defined by PPM variances) and will not affect consumer’s health or have an adverse influence on the product’s use.
02 Right Lubricant For The Application
The variety and complexity of applications within the industrial market do not allow for a ‘one size fits all’ lubricant for every possible situation. Each application has its own unique requirements for viscosity (low and high temperature variances), corrosion and rust protection, cleanliness, extreme pressure, antiwear, antifoam, water separation and oxidation inhibition.
Generally, there are basic performance characteristics needed for each application. For example, a gear lubricant needs to provide extreme pressure properties among other requirements; an air compressor lubricant needs to provide oxidation stability and cleanliness.
Formulators determine which additives to blend in to meet specific performance needs for the lubricant. Drain intervals, filter changes, and regular fluid monitoring and analysis help to ensure the operation continues running at optimum efficiency.
Decreased downtime, increased energy efficiency and fewer oil interval changes can translate into cost savings for an operation. Upgrading to higher performing products (synthetics) may be a good option to help achieve these operational benefits.
Consulting with a lubrication engineer can also help to ensure the best lubricant is selected. They will consider all known variables including operating conditions, application requirements, food grade classification requirements and any formulation restrictions.
03 Materials Compatibility
Lubricant compatibility with various material types used within a food processing facility should be carefully considered. Engines, compressors, pumps, gear boxes, and other components in a mechanical system can be made of different types of metallic components. Selecting a lubricant formulated to address the specific requirements of a metal (or multiple metal types) under typical operating conditions is important.
Variables such as metal type, movement of machine parts, and operating temperature range are critical in understanding how the lubricant needs to perform within the system.
Seals, gaskets, hoses and other plastic/rubber components are equally as critical to ensuring equipment longevity. If the lubricant damages the integrity of a seal because of poor compatibility, it can cause it to break down or deteriorate completely. The loss of oil from leaks (causing downtime) can add significant costs to an operation.
ASTM 471 Section 10 (Standard Rubber Property-Effect of Liquids) is commonly used to evaluate the comparative ability of rubber and rubber-like compositions to withstand the effect of fluids, such as lubricants. The seal will shrink when components of the seal are extracted into the lubricant, and swelling is caused when lubricant components migrate into the seal. Both shrinking and swelling of the seal can cause oil loss when occurring in excess.
04 Base Stock Considerations
Lubricant manufacturers have a somewhat limited selection of base oils to choose from when formulating solutions for the food and beverage processing industry. The classification (H1, H2, etc.) of lubricant required also dictates which base oils the formulator can select.
As an example, for the H1 classification, polyalphaolefins (PAOs) and white mineral oils (WMOs) are the most commonly used base oils. Other synthetic base stocks such as polyalkylene glycols (PAGs) can be used, although they are not utilised frequently.
The base stock is the main constituent of the fluid, and the use of synthetic oils can benefit the finished lubricant by:
- Improving thermal and oxidation stability (drying or sterilising food process)
- Improving viscosity-temperature characteristics (high viscosity index need for refrigerated or high temperature areas)
- Lowering volatility and evaporation rates
- Extending oil drain intervals
- Reducing operating temperatures especially under fully loaded conditions
- Reducing energy consumption
There are also several additives the formulator can use to overcome the deficiencies of a base stock oil. Additives can be selected through the specific guidelines found within 21 CFR 178.3570 for H1 lubricants. Another option is to have proprietary additives, exclusive to a company, formulated for use so long as the chemistry is supported with proper data to ensure food safety.
Contamination—or rather reducing the possibility of contamination—plays a rather significant role in the selection of base fluid and additive choices.
In environments where high water contamination is likely, a lubricant with excellent separation characteristics needs to be considered. If a grease product is used, then low water washout characteristics are ideal.
In certain operations, the use of water throughout the system in general, or to clean (when used as steam) can be a significant part of the process. Synthetic lubricants, such as PAOs, generally offer better water resistance characteristics which help combat rust and corrosion issues.
Selecting the right lubricant for use in a food processing facility can be challenging. The increased health and safety aspects, in addition to customary operating requirements, add to the complexity of the decision. Fortunately, there are ways to alleviate much of the ambiguity surrounding all the different lubricant options available.
In general, focusing on the specifications of the application and being knowledgeable of the lubricant’s classification and chemistry will aid tremendously in the selection process.
Food industry applications that are more challenging may require consultation with a lubricant engineer. The application may involve multiple factors to ensure quality, efficiency and safety standards are met. Moreover, it may be easier to consult with a lubricant engineer than attempt to acquire the knowledge and expertise required to make the selection.
The proper lubricant will add value to the food processing operation by maximising efficiency and reducing the possibility of health and safety issues for the end-use product.
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