Compressed Air – a hidden contamination risk

Lubrication is required for running a air compressor smooth and efficient. However, contact is possible between compressed air and lubricant, so that oil mist can come in the air. Replacement by oil-free compressors can be avoided by switching to food grade lubricant specially developed for compressors. As a result, it is possible, in the event of contact, to stay within the FDA standards, while the operation of the compressor can even improve.

The presence of air compressor lubricant in compressed air can be a major area of concern for food & beverage manufacturers. Commonly used in food processing plants, compressed air is used to mix liquids and provide safe power delivery for critical tasks in areas such as material transport, filling lines, spray applications and drying. However, as the majority of air compressors are oil lubricated, food safety can be quickly compromised by the use of non-food grade compressor oils.

Essential to the smooth and efficient running of air compressors, lubricating oils help to reduce metal-to-metal contact between the compressor’s rotor or helicoidal screws and the cylinder housing. This helps to minimise expensive component wear and damage, reducing unplanned downtime and enabling operators to realise the low maintenance and reliable performance benefits of compressors. As compressors operate in close proximity to food stuffs, there is a realistic threat of accidental oil contact, which is why Shell lubricants companies have developed a new food grade compressor oil.

Oil Mist Risks

Oil mist can form in compressed air as a result of high operating temperatures and can be difficult to detect. This increases the threat of the oil mist coming into direct contact with food; a problem that can easily go unnoticed until detected by the consumer. By this time though, it can be too late, as consumer health and welfare has been jeopardised. This can bring the company under public scrutiny, which can severely impact on long-term market performance and survival.

The amount of oil in compressed air depends on a number of factors, including the condition of the machine and how regularly it is maintained, the condition of the coalescer and filters and whether parts that have been fitted have been recommended by the original equipment manufacturer. Other risk factors include the age of the compressor oil, whether the correct oil is being used and whether secondary filters have been fitted. Failure to maintain and regularly replace filters will also increase the risk of contamination.

As Figure 1 shows, even when using multi-stage filtration, there is still a risk of contamination with food as oil particles remain in the compressed air. While a multi-filter system can reduce oil mist concentration to as low as 0.1 parts per million (ppm), it is impossible (under normal conditions) to remove 100 per cent of oil mist for an end result of 0.0ppm – the maximum tolerance of non-food grade lubricant contamination with food and beverages allowed by the US Food and Drug Administration (FDA).

Shell / Lubritech
Diagram of oil and air flow around compressor

Fig. 1. It’s impossible to remove 100% of oil mist

Reducing Contamination

While it is possible to avoid the presence of an oil mist by using an oil-free compressor, this is an expensive option requiring replacement of existing non-oil free compressors. A much more cost-effective solution for operators is the use of food grade compressor oils. Specifically developed for use in air compressors, high quality, synthetic, H1 approved, food grade compressor oils such as Shell Cassida ® Fluid CR 46 have been formulated using approved additives and base fluids. This composition means that Shell Cassida Fluid CR 46 is tasteless, colourless and odourless and will not contaminate food in quantities less than the US FDA’s maximum permitted level for H1 lubricants of 10 parts per million.

Fully registered by the NSF as H1 for incidental food contact, Shell Cassida Fluid CR 46 is a fully synthetic oil that can increase food safety and compressor performance. Cassida Fluid CR 46 has excellent high temperature resistance to oxidisation, which reduces gum and lacquer deposits on the coalescer, reducing filter saturation and the risk of oil mist. As well as improving air quality, the reduction in deposits enables better fluid circulation and lubrication of the compressor, improving efficiency and lowering maintenance costs.

Cassida CR 46 – Food Grade Performance
Atlas Copco oil-flooded GA 37 screw compressor, after 5,756 hours

Shell / Lubritech
Clean Coalescer

Clean Coalescer will remove oil mist efficiently

Shell / Lubritech
Oil filter mounting

Oil Filter Mounting Plate: no sign of oil oxidation

This compressor was running on a competitor fluid, which showed deposits before the oil change at 4,000 hours. It was flushed and filled with Shell Cassida Fluid CR 46. After 5,756 hours on Shell Cassida Fluid CR 46, the coalescer and oil filter were inspected with the following results:

  • Both were found clean and free from deposits
  • Seals were in excellent condition
  • Oil Analysis showed oil still in excellent condition
    (oil should be analysed periodically)

Shell Cassida CR 46 has been used in these compressors:
Atlas Copco, Berko Compressors, Compair Hydrovane, Gardner Denver, Grassair, Hitachi Compressors, Ingersoll Rand, Rietschle, Vemag Maschinenbau GmbH.

Food Grade Benefits

Although the risk of compressed air contamination is difficult to detect, the consequences are much more visible…. especially on the bottom line. Excessive costs can be incurred as whole batches of contaminated food are destroyed and unadulterated products recalled. Furthermore, production lines may have to be completely stopped as the contamination incident is rectified and compressors cleaned.

High quality, synthetic, food grade lubricants such as Shell Cassida CR 46 can help operators to maintain cleaner air and improve food safety levels, reducing the adverse impact of oil mist contamination. These safety benefits are supported further with excellent compressor oil performance, which can lead to extended oil drain intervals, meaning that operators do not have to make a choice between performance and safety.


Soft Drinks Industry Winters

The rich history of Soft Drinks Industry Winters BV is now in its third century. Today, the bottling company is alive more than ever. With a flexible attitude and high quality standards it has become the largest Dutch soft drinks exporter. In addition, the lubricants of Shell Lubricants make the machines run optimally and food safe.

"You ask, Winters fills": that's the motto of Soft Drinks Industry Winters BV in Maarheeze (North Brabant, The Netherlands). The company is not directly known to the consumers: the company has never sold soft drinks under its own name. Still, it can look back on a long and rich history. When William Van Hooff laid the founding stone of his brewery on August 5, 1797, he could not have realised that it would become an international soft drink company in two centuries time. By inheritance to the next generations in the year 1873 Jan Winters came in charge. Since then, the brewery was known by his name. In 1918 the production of soft drinks started. Until 1958 Winters only had regional ambitions. Then the company expanded business and Winters became producer of world renowned branded as Seven-Up, Sunkist and Canada Dry. When the domestic sales of soft drinks stagnated, the sight was set on various foreign markets in the seventies. In 1978 the company became part of TLC Beatrice International Holdings. Together with the Belgian soda bottling Sunco, who belonged to the same group, it took over the French mineral water producer St. Alban in 1996. After a management buyout the holding company Sun Beverages Company emerged in 1998, comprising Winters, Sunco and St. Alban.

Contract filling

In 1989 the licenses for the production of Seven-Up and other branded products for the Dutch market ended. Since then all attention is directed to 'contract filling'. This is done on behalf of major international food companies, retailers and other commercial organizations. Winters fills cans for a range of soft drinks, energy drinks, mixed drinks, juices, waters and beers with well-known brands. Between 5 and 10% of production is destined for its own brands, such as Sun Cola and Orange, Party Cola and Orange, Provita multivitamin drink, Maresca mineral water and Megaforce energy drink. Nearly 95% of the volumes is exported worldwide and thus Winters is immediately the biggest Dutch soda exporter. Every year more than 500 million cans are filled, packed and logistically processed. Winters currently employs 120 people in permanent employment and dozens of seasonal workers. Production runs per working day in three shifts for 24 hours and during the peak season in a four or five shifts.

To realize such large numbers, Winters has three production lines. An important part of each line is the can sealing machine running at very high speeds. Two machines seal 1,200 filled cans per minute and the third will do another 625 units per minute. Frans Cox, head of utilities and engineering projects: "Such devices are very capital intensive. It is very important that they remain in good condition to produce an excellent product with a constant quality. "

For the reliability of the sealing machines the right food grade lubricants are essential. Some parts are lubricated with oil, others with grease. Oils are able to dissipate more heat and are regenerable by filtration. They are applied for the lubrication of (plain) bearings and gears. Fats are oils encapsulated in soap skeleton. They have less heat-dissipating properties, and can not be reused. The fats serve, inter alia, for the lubrication of bearings in hemming rollers. Incidentally, their lubricating frequency is lower than that of oils.

One supplier

Until ten years ago, Winters used lubricants from various manufacturers. F. Cox: "However, the need hasd arisen to rationalise the diversity of products and providers. To get a better overview, we decided to give one person decision-making authority and to work with just one supplier. The result is that if there are questions, there is only one firm where you can go to the right person. That's an advantage, because of the high speeds the machines are very sensitive and, if necessary, you should be able to rely on a rapid intervention of your lubricant supplier."

Arjan Nieuwstraten, food sector specialist of Shell Lubricants, adds: "The material of a modern beverage can is much thinner than before and therefore the method of sealing is more critical. So you can imagine the tolerances to have to work with will be smaller than before. The importance of the lubrication is thus become much greater. "

At that time Winters already bought around 70% of its lubricants from Shell Lubricants and, partly by this collaboration this supplier was chosen. "The people at Shell were always coming into action directly when needed. They were also always ready for the start up of new equipment, switching to newer oils or fats, assistance in making lubrication schedules, etc. That's why we did not have to think long about who we wanted to go into business with", F. Cox continues.

In practice, there is now a 'gentlemen's agreement' between the two parties. "A synergy has grown between our companies, based on years of trust", A. Nieuwstraten confirms. "The collaboration with Shell Lubricants is closely aligned with the expectations that we have with respect to our suppliers", F. Cox adds.

Incidentally Shell offers Winters an additional service with the Lubriplan software. This lubrication management system provides an accurate overview of the inspection points for fats and oils in the machines and generates user-friendly instructions. So it is indicated where and with what frequency there has to be checked or lubricated and with what product that needs to be done. "Moreover Lubriplan builds up a history of the objects to be lubricated. It may sometimes appear that periodic lubrication at a certain location is needed less frequent than planned. Such cost optimisations we do proactively for Winters", A. Nieuwstraten continues.

Food safety

In this industry, food safety is of paramount importance and it is essential that no contamination of the filled product occurs. The past decades mineral (engine) oils were used to lubricate can seaming machines. Because these are unfit and improper to come into contact with food, Shell Lubricants has developed a range of food grade oils and fats which are suitable for the lubrication of such equipment. They may be used in the food industry and meet the European standard and the US FDA NSF H1-H1. The FDA (Food and Drug Administration) considers incidental contact of these lubricants with the food product to be acceptable to a level of 10 ppm (parts per million). The lubricants are food safe without compromising on their lubricating properties.

Incidentally, there are two types of food grade products. In some sealing machines the lubrication takes place in a closed circuit: this process is called "recirculating oil '. For such systems Shell Lubricants has developed the synthetic oil 'Shell Cassida Fluid GLE' series. That series has excellent lubricating properties and is recognized by leading suppliers of sealing such as Angelus (USA), FMC FoodTech (Belgium) and Ferrum (Switzerland). A second process is that wherein the lubricant is used only once: the "total-loss system. For this, Shell introduced the food grade mineral oil 'Shell FM Gear Oil TLS 150'. That delivers outstanding performance, even in the presence of water, juice or beer. Moreover, this oil absorbs water, preventing rust.

Remarkable is that these Shell products were developed in cooperation with Soft Drinks Industry Winters. A. Nieuwstraten: "We gave attention both to food security and to the optimization of lubricant performance. At Winter we have gained a lot of knowledge about the lubrication of sealing machines with these products and numerous tests have led to the most sophisticated lubricants for this sector."

Quality Systems

Large beverage producers that have known branded products manufactured through contract fillers not only value high the quality of the final product. Also, the extent to which the production process is controlled and hygiene risks are avoided, plays a major role for them. Winters has responded and holds international quality certificates according to ISO 9000, 14001 and HACCP (hazard analysis critical control points). In addition, the bottling company is certified to the BRC standard (British Retail Consortium). That standard contains guidelines which food producers have to meet in order to supply the large English supermarkets. Finally, for German and French retail chains Winters has the IFS certificate (International Food Standard).

With the high quality food grade lubricants of Shell Lubricants and the high quality standards of Winter the consumer profits.

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Featured expert: Wouter Burggraaf

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