How to Select the Right Grease

Selecting a grease or lubricant is one of the most crucial decisions you make in regards to any machine. Your selection might make the difference between cost savings, reduced downtime, or significant unexpected costs and failures. For oil lubricants, many OEMs specify what product or what type of product is recommended for each component of their equipment. This simplifies the selection process. However, OEM grease specifications are much broader. Most of the time OEMs simply recommend the National Lubrication Grease Institute (NLGI) specification.

This presents both flexibility and options, but also introduces more room erroneous decision-making and poor lubrication. Simply using the NLGI grade is not enough. You have to look at other factors to ensure you grease and machine work properly and does not fail. We will look at some key factors that every operator needs to consider.

Base Oil Viscosity

A grease is composed of 3 ingredients: thickener, oil, and additives. The NLGI number indicates the thickness of the thickener, but does not specify the viscosity of the thickened base oil. The underlying base oil has its own viscosity just like any lubrication oil. If a piece of a equipment calls for a certain lubricating oil with a specific viscosity, it is easy to find a grease that has the same base oil viscosity and similar additive package.

If viscosity requirements are not specified, you can use the chart below (courtesy of ExxonMobil and Noria).

The two factors required are operating temperature and DN or NDm, which are the bearing speed factors. To calculate those speed factors, simply use the following formula:

  • DN = (rpm)*(bearing bore) and
  • NDm = (rpm)*((bearing bore + outside diameter) / 2)

The intersection of DN and Temperature will point you towards the required ISO viscosity. This chart assumes viscosity index.

Base Oil Type and Additives

Once a viscosity is identified, you need to figure out what additives and base oil you need. Similar to oil lubricants you must assess your operations and figure what additives are necessary or unnecessary. For example, light loads and high-speed applications do not require a grease with extreme pressure (EP) additives, but a heavily loaded application will need those EP additives. The chart below breaks down the needed additives for various bearings.

Courtesy of Noria

Most greases use mineral oil and only require mineral oil. However, synthetic base oils are recommended for certain extreme temperature applications. Applications with low or high operating temperatures or a wide range of temperatures, a synthetic base oil is recommended. Synthetic base oil greases are also recommended for users who want to longer regreasing intervals.

Grease Thickener

Unlike lubricating oils, greases include thickeners. The two factors that distinguish grease are type and consistency. As mentioned earlier, consistency is based on the NLGI scale. The scale ranges from 000 (most fluid) to 6 (least fluid). The most common and most recommended NLGI grade is #2. Most OEMs specify the NLGI grade and matching that number is a simple process (especially if you require a NLGI 2 grease).

The other factor for thickeners is the type of thickener. The differences between each type of thickener are present pros and cons for each application. The most common types are lithium soap, lithium complex, and polyurea. Lithium soap greases are low-cost general-purpose grease and perform well in general applications. Lithium complex is similar to lithium soap, but is preferred for applications with higher operating temperatures. Polyurea greases have good high-temperature properties and have high oxidation stability and bleed resistance. When switching greases, it is important to understand thickener compatibility to make sure the new grease does not fail.

Cost and Other Considerations

When purchasing a grease, a basic lithium grease will be cheaper than a sophisticated polyurea grease. It is up to you to determine the tradeoffs between grease costs and performance gains/losses. Purchasing a higher quality grease may lead to longer regreasing intervals and less machine failure.

To save costs, consolidating greases may be wise, but be wary of over-consolidation. This may result in some machines not using an appropriate grease.

Other attributes should be considered depending on the application. Some grease exclusive attributes include:

  • Drop Point
  • Mechanical Stability
  • Water Washout
  • Bleed Characteristics
  • Pumpability

Certain attributes are focused specifically on heavy loads and should be considered for heavy load-low speed applications. These include:

  • Four-Ball Tests
  • Timken OK Load

Additionally, industry specific requirements will also dictate grease selection. These industries have strict requirements and require greases to be certified by certain 3rd-party regulators:

Conclusion

Unlike oils, greases have many more factors for product selection. These factors should be considered for each application as each grease is designed and manufacturer specifically for each application and have a delicate balance of thickener, oil, and additives.

Twin Specialties carries a wide variety of greases to meet you application needs. We work directly with you to make sure we provide the right product that delivers performance while being mindful of the total cost of grease and maintenance. Contact Twin Specialties to learn more about our grease product lines.

What are Biodegradable Lubricants?

As the world’s petroleum reserves are extracted, scarcity increases, thus driving oil and lubricant prices higher. This economic burden will force end-users and manufacturers to develop alternatives that are cost effective, readily available, and sustainable. The answer to these concerns are biodegradable lubricants.

Biodegradable Lubricants Defined

Biodegradable lubricants have the ability to degrade naturally by the actions of biological organisms. Petroleum is naturally occurring and is considered inherently biodegradable. However, that does not mean they can be marketed, sold, and treated as biodegradable. When we refer to biodegradable lubricants, we are discussing lubricants that are readily biodegradable.

Determining Biodegradability

Biodegradable lubricants must meet the ISO 9439 or OECD 301B standards. These standards state that a lubricant that has degraded by more than 60% within 28 days is readily biodegradable. The tests involve treating a lubricant sample with microorganisms in the presence of oxygen and measuring the CO2 produced by the microorganisms. As mentioned before, petroleum-based lubricants are inherently biodegradable, but not readily biodegradable because they fail to meet these standards. Petroleum-based lubricants naturally degrade at a rate of 15-35% in 28 days, falling short of the required 60%.

Additionally, the lubricant must be of “low toxicity.” There are a variety of tests used to determine toxicity. These tests involve fish, daphnia, and other organisms. In their pure form, mineral oil and vegetable oil show little toxicity, but lubricants are not just pure oil. As additives are incorporated into formulations, the toxicity increases. Additives are added to make up for any performance shortcomings of biodegradable base stocks.

Types of Biodegradable Base Stocks

Most biodegradable lubricants use vegetable oil, synthetic esters, polyalkylene glycols (PAGs), or a combination of these as base stocks. Vegetable oils have been used for years when petroleum was in short supply. They were popular during World War I and World War II due to oil rationing and came back in popularity during oil embargo in the 1970s. Vegetable oils declined in popularity due to the availability of low-cost oil after Desert Storm. Their popularity is beginning to rise as more manufacturers and end-users are faced with climate change and sustainability concerns. Some common vegetable oils used are soybean oil, cottonseed oil, olive oil, sunflower oil, and canola oil. To improve performance, farmers are beginning to grow genetically modified crops that are designed and engineered for use in lubricants.

Synthetic base stocks, such as esters and PAGs, are also used to boost performance when vegetable oils cannot get the job done. PAGs are effective, however they have a few issues that should be considered. PAGs are incompatible with other oils and can cause problems if inadvertently mixed with non-PAG oils. PAGs can also react poorly with seals and paints. This is why synthetic esters are preferred for biodegradable lubricants. Synthetic esters are typically added to vegetable-oil based lubricants to improve low temperature properties. These serve better than light mineral oils as synthetic esters are less toxic and more biodegradable.

Biodegradable Lubricant Products

Many applications and machines now can be lubricated with biodegradable lubricants and meet all performance requirements. Products that can be composed of soybean oils include:

  • Food grade hydraulic fluids and greases
  • Automotive, railroad, and machine greases
  • Tractor transmission and industrial hydraulic fluids
  • Chainsaw bar oils
  • Gear lubricants
  • Compressor oils
  • Transmission and transformer line cooling fluids

Many more products are in development and could become viable in lubricant markets soon. These include:

  • Two-cycle engine oils
  • Metalworking fluids
  • Specialty lubricants

With more resources and demand for biodegradable lubricants, engineers and manufacturers can research and develop more products that perform more applications, perform better than mineral oils, and remain price competitive.

Biodegradable lubricants are highly popular in applications and industries where environmental and safety concerns are high. Marine and agricultural industries need these lubricants as contamination could have devastating effects. According to Total Lubricants, a single liter of oil can pollute as much as 1,000,000 liters of water. In those applications, biodegradable lubricants are essential. Some government regulations ensure that these industries use biodegradable lubricants that do not harm consumers and operators in the event of leakage.

Twin Specialties Offers Biodegradable Lubricants

No matter your application or environmental requirements, Twin Specialties can meet your manufacturing, marine, or agricultural needs. We offer a variety of lubricants including: Shell Naturelle, Castrol Performance Bio, and various Food Grade lubricants. Contact Twin Specialties for a quote.

A Guide to Food Grade Lubricants

In the food and beverage industry, health, safety, and quality are of the utmost importance. The ever-evolving standards of food and beverage safety make it important to ensure your plant is deploying the proper lubricants and cleaners. Not only do you have to meet performance standards, you also have to monitor leakage to ensure that final products are not getting contaminated. We will examine the evolving standards of food-grade lubricants and cleaners as well as the challenges in finding the right products to meet both health and performance standards.

From USDA to NSF

The original designations created by the USDA sought to organize food-grade lubricants into three categories. The current standards are listed below for each category:

  • H1 lubricants are used in food-processing environments where there is the possibility of incidental food contact. These lubricants are tasteless, odorless and inert. H1 lubricants are safe for human consumption in small amounts, under 10 parts per million (ppm). They are most often used in for machinery such as conveyors and mixers. Applications of these lubricants include: blending, cutting, bottling, brewing and many more.
  • H2 lubricants are used on equipment and parts where there is no possibility of incidental food contact, such as forklifts. Even though there is no contact, H2 lubricants must adhere to strict toxicology standards. H2 lubricants may not contain trace elements of: carcinogens, mutagens, teratogens, mineral acids or heavy metals.
  • H3 soluble oils are used to prevent rust on hooks, trolleys, and similar equipment. These products are typically made of edible oils such as: corn oil, sunflower oil or soybean oil. H3 lubricants are inherently biodegradable and comply with 21 CFR Section 172.860 and 172.878. They also comply with 21 CFR 182 and 184 in regards to GRAS substances.
  • 3H release agents are used on surfaces with direct contact to prevent food from adhering during processing. These lubricants can be used to aid in processes where contact is unavoidable, such as removing baked goods from a mold.
  • HT1 are heat transfer fluids used in primary and secondary heating and cooling systems in food processing facilities. These must comply with 21 CFR 178.3570 and 21 CFR 172.

The USDA served as an authority for approval and compliance. Manufacturers had to prove all components were allowable substances under 21 CFR 178.3570. The USDA stopped issuing registrations on September 30, 1998. Since then, many organizations have adopted and modified these standards.

After 1998, The German Institute for Standardization (DIN) submitted a standard to the International Organization for Standardization (ISO). Eventually the ISO adopted ISO 21469, which pertains to lubricant manufacturing, and ISO 22000, which pertains to food safety systems. However, the most recognized standards are those put forth by the National Sanitation Foundation (NSF).

As a successor to the USDA, the NSF has updated the USDA standards to improve health and safety for consumers. The current NSF standards are similar to the old USDA standards, using the H1, H2, and H3 designations. Additionally, the NSF created the HX-1 standard for ingredients. These HX-1 ingredients are pre-screened and meet requirements for finished H1 lubricants. The NSF has established itself as the recognized international standard and operates in over 80 countries around the world.

Selecting your Food-Grade Product

In the food & beverage industry, health and safety is by far the most important concern. One contamination, recall, or illness outbreak can do irreparable damage to a company’s brand and business. Therefore, it is imperative to consider selecting products that go beyond required standards. Opting to use H1 lubricants is an excellent example of meeting compliance and protecting your brand. This eliminates the possibility of using an H2 lubricant when an H1 is required. H1 lubricants can act as insurance to your brand’s equity and will reduce liability in the event of equipment or plant issues.

Performance is key when selecting a lubricant, but achieving peak performance may be more difficult with food-grade lubricants. H1 products tended to fall short compared to their H2 counterparts. This was due to the limited number of H1-registered additives compared to H2-registered additives (including zinc-based components).Food & Beverage

New NSF HX-1 additive packages have dramatically improved the performance of H1 lubricants while also meeting the rigorous standards set forth by NSF H1 lubricants. For grease thickeners, aluminum sterate, aluminum complex, organo clay, polyurea and calcium sulfonate meet H1 standards (lithium thickened greases do not). You can now use an H1 lubricant and achieve the high performance demanded from your business. It simplifies the selection process by allowing you to use H1 lubricants throughout your plant.

These additives are now paired with synthetic base oils such as polyalphaolefins (PAOs), polyalkylene glycols (PAGs), and esters. These base oils along with HX-1 additives can deliver premium performance while protecting the integrity of your brand. Selecting a product also depends on your specific processes and it is important to consider unique contaminants that may affect product performance.

Other considerations may include dietary standards. It is important to ensure your lubricant meets any Kosher or Halal requirements. Failing to do so may result in products not suitable for those whose follow Kosher or Halal diets. This results in a smaller customer base and will affect bottom lines. It could damage brand integrity if a product is marketed as Kosher or Halal and is later found to fall short of these requirements.

Takeaways

Although no government is responsible for food-grade lubricant standards, the NSF has established itself as a leader in food-grade lubricant regulations. Operating as a nonprofit in over 80 countries, the NSF ensures that your food-grade lubricants meet their rigorous standards. Modern advancements in additive technology and base oil technology have led to lubricants that are NSF compliant and meet the highest performance standards. There is no need to sacrifice safety for quality anymore.

Twin Specialties offers a wide-range of food-grade products including lubricants and cleaners. We offer products from Castrol, CRC, Lubriplate, and many more to meet your food and beverage manufacturing needs. Contact us to learn more or get a quote.