PAG technology a new staple for food-grade lubricants

There have been significant advances in H-1 lubricant research and development over the years which have produced top performing products. The search for an even better performance by lubricant manufacturers continues, specifically in the food safety field and effects on the environment.

01/10/2011


Since the original introduction of H-1/food grade lubricants into the food, beverage and pharmaceutical processing industries in the early 1960s, there have been significant advances in H-1 lubricant research and development which have produced top performing H-1 products. Polyalkylene Glycol (PAG) fluid technology is a shining example of these performance advances.

The original introduction of food grade lubricants into the food and beverage industry in the 1960s had two purposes: to provide protection for machinery, and to maintain food safety. In the beginning, food and beverage manufacturers were generally limited to using USP white oils having no additives. Functional lubricants were non-food grade conventional industrial lubricants.

Continuous improvements since the 1960s have led to today’s food grade lubricants which provide superior performance in hydraulic systems, gear and chains, compressors and many other standard applications.

Although the lubricant industry has achieved many successes, the search for even better performance by lubricant manufacturers continues. To food safety, there has now been added consideration of the impact of food grade lubricants on the environment. Most food plant managers have switched from non-food grade lubricants to advanced lubricants; however, there are still some who believe the performance or the cost of the advanced lubricants does not give them an edge over conventional industrial lubricants. But inevitably there are still occasions when a lubricant leak from machinery comes into contact with food being processed, resulting in fines or product recall.

A researcher seeking to develop a food grade lubricant to serve a specific purpose can select from base stocks and additives that have been approved by the Food and Drug Administration, as well as from a long list of substances in the Generally Recognized As Safe category. These are substances that have not been approved by the FDA, but that have been in long use as ingredients in foods and beverages.

Food grade lubricants are approved and registered by the National Sanitary Foundation, a non-for-profit organization. Before 1999, approval and registration had been in the hands of the USDA. The NSF registers lubricants according to the FDA-approved ingredients listed in 21 CFR 178.3570, “Lubricants with Incidental Food Contact or category H-1."

NSF toxicologists determine product acceptability based on FDA’s list of approved ingredients/raw materials against CFR 9, 21. NSF approval of a lubricant tells firms using the lubricants, as well as FDA inspectors, that the lubricants used conform with food safety requirements. The NSF’s online “White Book” lists all currently approved lubricants.

Three categories

The NSF places each non-food compound that it approves into one of these three categories:

H-1: Compounds and lubricants that are approved for use on a machine whose lubricated parts may potentially come in contact with food. Collectively known as “incidental food contact lubricants,” these are the lubricants that are approved for food and beverage manufacturing.

H-2: Compounds and lubricants that may be used on equipment that is sufficiently removed from food processing operations that there is no possibility of the lubricant or lubricated parts coming in contact with food. A remote compressor that provides air to food processing equipment is an example of the equipment that uses compounds and lubricants from this category.

H-3: Water-soluble lubricants often applied to equipment manufacturers to new equipment to avoid rust and corrosion during transport. These lubricants intended only for temporary application during transport, and are not acceptable for use in food processing plants and must be removed before the equipment enters production.

Within the Category H-1 food grade lubricants which comply with the FDA CFR 21, 178.3570 there are four types of approved lubricants. Plant managers can select from the following types of food grade lubricants:

  • White Mineral Oils
  • Natural Oils
  • Polyalphaolefins (PAO)
  • Polyalkylene Glycols (PAG)

The first two types are made using natural or non-synthetic base stocks. The latter two types are made from synthetic base stocks. Much of the progress in matching a food grade lubricant to the needs of an application have come from synthetic fluids, and of these the most significant are the PAGs.

PAGs are made from the reaction of alkylene oxide monomers to form polymers, which are composed of ethylene oxide and propylene oxide. Lubricants based on PAGs have been received favorably by food manufacturers because their performance exceeds the performance of lubricants whose base stock is a mineral oil.

A key reason for the superiority of PAGs is their ability to provide sufficient lubrication even in the presence of water. PAGs can be fine-tuned to achieve optimum performance. If the PAG polymers contains a higher percentage of ethylene oxide, then the base stock will have higher solubility in water; if the polymers contain a higher percentage of propylene oxide, the base stock will have lower solubility in water. Blending different PAG base stocks permits the production of lubricants that meet specific targets for viscosity and other properties.

Performance advantages

PAGs are also less harmful to equipment that has accidentally over-heated. Lubricants in the other three groups - white oils, natural oils, and PAOs - tend to leave a residue of carbon, gum or varnish. PAGs experiencing the same conditions leave practically no residue.

In addition, PAGs have excellent lubricity, low toxicity, and a high index of viscosity. They are biodegradable, have good cold flow behavior, and have good oxidative and thermal stability. Overall, PAGs represent a dramatic improvement of the base stocks that were being used in the 1970s.

PAG’s can be used to formulate food grade lubricants for applications such as compressors, hydraulic systems, gears and chains, and many other applications in food plants. Lubrication manufacturers use PAGs to develop lubricants specifically targeted for gear and chain applications for the food industry,

These are fully formulated, extreme pressure gear lubricants designed for use on worm and hypoid gears. They were developed with select ingredients identified in FDA regulation 21 CFR 178.3570 for use in situations where incidental food contact may occur. They have been registered with the NSF international under the H-1 classification.

PAG-based food grade gear lubricants provide high lubricity (i.e., a lower coefficient of friction), and have a high viscosity index that permits them to be used over a wide range of operating temperatures. When overheated to decomposition temperatures, these gear oils produce no sludge, varnish, gums or tars. Instead, PAG-based gear and chain oils, when they reach decomposition temperatures, convert to simple molecules and evaporate without leaving hard carbon deposits.

Because PAG’s inherently have lower coefficient of friction the gear box runs cooler. Most gear sumps tested were found to be cleaner compared to those lubricated by mineral oil based gear oils. Limited scale testing of energy consumption showed that these lubricants may enable a machine to use up to 8% less energy than an identical machine using petroleum-based industrial gear oils or food grade white oil based gear oils.

Lower energy requirements and superior thermal stability mean that these products will have longer life. In addition these lubricants biodegrade rapidly and have lower impact on the environment.

Longer Life with PAG - Typical Properties of PAG Gear Oils
Lubriplate PGO 100Lubriplate PGO 150Lubriplate PGO 220
Viscosity at 40°C102.4156.0221
Four-Ball Wear Test0.520.540.53
Weld Load Kg160160160
Load Wear Index32.933.433.4
FZG Wear Test, Pass Stage121212
Ibs/Gallon8.78.78.7

A side-by-side field trial testing with the PAG gear oil and AGMA 5 petroleum based gear oil showed that the worm gear box unit ran about 15°F cooler on the new gear oil. At the same time, power consumption measured was about 7% less. Physical properties of the gear oil are shown in Chart 2.

Conclusion

High performance food grade PAG-based lubricants match or exceed the performance of conventional non-food industrial lubricants. PAG-based lubricants tolerate food chemical contaminations and water, and thereby increase the longevity of both the lubricant itself and the food processing machinery on which it is being used.

Sibtain Hamid is General Manager for the Toledo, OH operations and corporate technical director for LUBRIPLATE Lubricants Company. He can be contacted at (419) 697-4156 or by e-mail at shamid(at)lubriplate.com

Also see Centralized systems can deliver proper lubrication



Top Plant
The Top Plant program honors outstanding manufacturing facilities in North America.
Product of the Year
The Product of the Year program recognizes products newly released in the manufacturing industries.
System Integrator of the Year
Each year, a panel of Control Engineering and Plant Engineering editors and industry expert judges select the System Integrator of the Year Award winners in three categories.
October 2018
Tools vs. sensors, functional safety, compressor rental, an operational network of maintenance and safety
September 2018
2018 Engineering Leaders under 40, Women in Engineering, Six ways to reduce waste in manufacturing, and Four robot implementation challenges.
July/Aug
GAMS preview, 2018 Mid-Year Report, EAM and Safety
October 2018
2018 Product of the Year; Subsurface data methodologies; Digital twins; Well lifecycle data
August 2018
SCADA standardization, capital expenditures, data-driven drilling and execution
June 2018
Machine learning, produced water benefits, programming cavity pumps
Spring 2018
Burners for heat-treating furnaces, CHP, dryers, gas humidification, and more
October 2018
Complex upgrades for system integrators; Process control safety and compliance
September 2018
Effective process analytics; Four reasons why LTE networks are not IIoT ready

Annual Salary Survey

After two years of economic concerns, manufacturing leaders once again have homed in on the single biggest issue facing their operations:

It's the workers—or more specifically, the lack of workers.

The 2017 Plant Engineering Salary Survey looks at not just what plant managers make, but what they think. As they look across their plants today, plant managers say they don’t have the operational depth to take on the new technologies and new challenges of global manufacturing.

Read more: 2017 Salary Survey

The Maintenance and Reliability Coach's blog
Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
One Voice for Manufacturing
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Maintenance and Reliability Professionals Blog
The Society for Maintenance and Reliability Professionals an organization devoted...
Machine Safety
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
Research Analyst Blog
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Marshall on Maintenance
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
Lachance on CMMS
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.
Material Handling
This digital report explains how everything from conveyors and robots to automatic picking systems and digital orders have evolved to keep pace with the speed of change in the supply chain.
Electrical Safety Update
This digital report explains how plant engineers need to take greater care when it comes to electrical safety incidents on the plant floor.
IIoT: Machines, Equipment, & Asset Management
Articles in this digital report highlight technologies that enable Industrial Internet of Things, IIoT-related products and strategies.
Randy Steele
Maintenance Manager; California Oils Corp.
Matthew J. Woo, PE, RCDD, LEED AP BD+C
Associate, Electrical Engineering; Wood Harbinger
Randy Oliver
Control Systems Engineer; Robert Bosch Corp.
Data Centers: Impacts of Climate and Cooling Technology
This course focuses on climate analysis, appropriateness of cooling system selection, and combining cooling systems.
Safety First: Arc Flash 101
This course will help identify and reveal electrical hazards and identify the solutions to implementing and maintaining a safe work environment.
Critical Power: Hospital Electrical Systems
This course explains how maintaining power and communication systems through emergency power-generation systems is critical.
Design of Safe and Reliable Hydraulic Systems for Subsea Applications
This eGuide explains how the operation of hydraulic systems for subsea applications requires the user to consider additional aspects because of the unique conditions that apply to the setting
click me