Choosing and Applying Lubricants in Food Processing Plants
New additives and base stocks improve their performance.
Mineral oil-based or synthetic? Food grade or not?
As with most things in business, choosing the right lubricants for use in your plant involves some considerations.
First and foremost is considering the potential for food contact. Not every machine in your plant could leak oil into a food product, but many could. Determine which ones have that potential and plan for the highest-grade lubricants, H-1.
Lubricants are grouped into three categories, depending upon their potential for food contact (broad definitions originally were developed by USDA but were handed over to accrediting body NSF International in 1999):
- H-1 - Lubricants with incidental contact: These compounds may be used on machines and in areas where contact with food is only incidental. They can be lubricants for moving parts or used as a protective anti-rust film or as a release agent on gaskets or seals of tank closures.
- H-2 - Lubricants with no contact: Whether serving as lubricant, release agent or anti-rust film, these compounds may be used only in closed systems or in locations where there is no possibility of the lubricant or lubricated part contacting a food product.
- H-3 - Soluble oils: These products typically are applied to hooks, trolleys and similar equipment to clean, lubricate and prevent rust. But those portions of the equipment that contact edible products must be clean and free of the mixture before making contact with food.
"Historically, food processors only used USDA H-1, or now NSF H-1 lubricants, in areas where they absolutely had to. The reasons typically were H-1 lubricants did not have the performance properties [for] more demanding applications and the cost differential when compared to traditional industrial lubricants," according to Fuchs Lubritech, Harvey, Ill."In recent years, this reasoning has become less of an issue."
Less of an issue for two reasons. First, the cost differential of traditional lubricants has been reduced due to rising crude oil costs (most H-1 lubes are mineral-oil based). Second, now more than ever, cost issues take a back seat to food safety, and even the remote possibility of a lubricant contaminating a food product is a risk most food & beverage processors do not want to take.
"Food safety and regulatory compliance continues to be top priorities for the food processing industry, and as a result we've seen strong demand for food grade lubricants, " says Colleen Flanagan, marketing portfolio manager for specialty fluids at Petro-Canada Lubricants.
"Increasingly processors have adopted policies that ensure the highest standards of food safety in plants. Many have adopted the HACCP system, which requires the use of H-1 food grade lubricants in equipment such as hydraulic systems, pumps, mixers, tanks chain drives and conveyor belts to eliminate the risk of incidental contamination by non-food grade lubricants."
Within the Category H-1 food grade lubricants, there are four types of approved lubricants: white mineral oils, natural oils, polyalphaolefins (PAOs) and polyalkylene glycols (PAGs), explains Sibtain Hamid, corporate technical director of Lubriplate Lubricants Co., Newark, N.J.
"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."
Lubriplate favors PAGs. A key reason is their ability to provide lubrication even in the presence of water. Also, "blending different PAG base stocks permits the production of lubricants that meet specific targets for viscosity and other properties," Hamid says.
PAGs also are 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 good oxidative and thermal stability. Overall, PAGs represent a dramatic improvement of the base stocks that were being used in the 1970s."
PAGs can be used to formulate food-grade lubricants for compressors, hydraulic systems, gears and chains and many other applications in food plants.
"We're also seeing more processing plants running 24/7," adds Flanagan. "The equipment is becoming more complex, speeds are increasing and the outputs are greater. All of this puts more emphasis on the need for the right lubricants."
The other issue, of course, is making sure the lubricants are applied and maintained. Solving that problem is Simatec AG from Wangen an der Aare, Switzerland, a manufacturer of automatic lubricators. Driven by a gas-producing dry cell, Simalube, the company's main product, can be applied to range of mechanical components, including conveyor belts, fans, motors, pumps, cooling and heating units, chains and guides. It works upside down and even under water. Lubrication frequency can be adjusted for periods from one month up to a year.
The company, with a U.S. office in Charlotte, N.C., claims it has "millions of grease and oil dispensers in use around the globe in many industries."
Some advantages to the automatic lubrication of parts is the regularity of maintenance, prevention of contamination and safety for plant personnel. "Lubrication points are often located in places that are difficult and dangerous to access," says spokesman Kevin Smith.
"Simalube helps reduce the number of maintenance intervals and inspection rounds required, therefore decreasing the chance of injury or delays. The automatic lubricator also makes it easier to comply with occupational safety standards, which in turn results in significantly fewer occupational accidents. They are approved and certified for use in all areas with potentially hazardous atmospheres."