Smooth operation

Keeping machinery running smoothly is a major concern in every manufacturing industry, but for food processors it poses particular problems.

Lubrication is as vital as ever, but where the product is intended to be eaten or drunk, it's more important than ever to ensure that it is either kept segregated from the product, or that the lubricant itself is completely non-toxic, flavourless and colourless.

Increasingly, food processors are opting for the latter, with food-grade lubricants finding more and more applications.

Food-grade lubricants are generally made from synthetic chemicals, such as polyalphaolefins, combined with a variety of additives. These will vary, depending on the application of the lubricant. For example, compressor oils often contain vitamin E, whose antioxidant properties prevent the oils from breaking down at high temperatures. Lubricants for hydraulic systems need anti-wear additives, generally containing phosphates and sulphur compounds. Chain oils need to cling to the chains and not be transferred onto other parts of the machinery, so they will often contain tackifiers.

Calypso Soft Drinks, based in Wrexham, turned to food-grade lubricants after finding that its existing lubrication techniques were falling short of the cutting edge. In fact, it was cutting edges that were the problem.

The company was using aerosol cans of vegetable oils to apply local lubrication to the cutting tool and cup slide on its cartoning machines, used to seal the drinks cups, Tetra-Paks and freeze pops that the company produces for supermarkets and other retailers. The aerosols were heavily used, with the company getting through 2300 cans per year.

This posed a number of problems, according to engineering stores manager Gary Rawson. 'Our main concerns were overuse of the lubricant, disposal of the empty containers, and the fact that we were still finding corrosion on the machines' cutting tools,' he says. Moreover, the aerosols were so readily available that they were frequently being used where food-grade lubricants were not required.

Disposing of the cans was a particular headache. Environmental legislation stipulates that a maximum of 250 empty aerosol cans can be disposed of in a single skip. 'With a waste management company charging approximately £200 for each load, disposal became a significant cost for the company.'

Faced with the problem of corroding blades, empty aerosols and a mounting skip bill, Rawson decided that the best way to proceed was to eliminate the spray cans altogether. He settled on installing a semi-automated spraying system from Shell Chemicals, and changed the lubricant to a higher grade product, Shell's Cassida Fluid HP15, a fully-synthetic product with low viscosity.

The system uses mobile spraying units, consisting of a holding tank fitted with a flexible hose and spray nozzle. The tank is pressurised with compressed air, allowing machine operators to deliver a spray of food-grade lubricants accurately and without waste.

The results have been tangible, with even Calypso's finance department seeing the effects. According to Rowson, the aerosol sprays were costing the company around £10 000pa for 920 litres of lubricant, even without disposal costs. The new equipment cost £2000, and the equivalent amount of Cassida costs £7200. Rawson notes that the company now uses much lower volumes of lubricant than previously, cutting costs considerably and making the company more environmentally friendly. 'The results in this case highlight the importance of regular evaluation and demonstrate the financial and environmental savings that can be achieved from just one operation,' Rawson comments.

One major advantage of food-grade lubricants is the safety angle. Even when lubricants do not come into contact with food products, many companies opt for food-grades throughout their operation as extra insurance.

For example, Durham-based meat products manufacturer Kerry Foods recently decided to switch from mineral oils to food-grade lubricants. Like Calypso, the company opted for Shell's Cassida range. 'As a result of Shell's research, development and testing, we now have a supply of food-grade lubricants, greases, sprays and penetrating oils that haven't just replaced the non-food products we used before, but have improved on their properties and performance,' says stores buying manager Ian Hepple.

The Cassida range used by Kerry Foods is composed of synthetic compounds which have been approved by the US Food and Drug Administration to H1 standard for incidental contact with food. And although not a prime concern for Kerry's pork sausage line, they are certified Kosher and Halal.

The safety-conscious use of lubricants is becoming ever more entrenched in food processing. Supermarket chains are now specifying that their suppliers should use food-grade lubricants throughout their operations, as a safeguard against possible contamination. Ian Holt, sales engineer at Rocol, which makes Foodlube lubricants, notes that 'we are seeing a big swing towards Foodlube in the food processing and catering industry.' One of the company's clients, Salford-based Canadian Pizza, specifically cited this reason when it switched to the product.

The concern is spreading to other types of food manufacturer. Rumenco, a cattle-feed manufacturer, uses Foodlube in its pressing plant. Cattle feed is considered to be part of the food chain, so food-grade lubricants are deemed necessary for all moving parts in the manufacturing process.

Rumenco had been suffering from lubrication-related mechanical problems, including the breakdown of a gearbox due to inaccurate application of lubricant which caused over two days' downtime. Because of this, the company opted for a mechanical application system, with a motorised unit applying the correct amount of lubrication to the precise locations required.

'Manual application of lubricants is both unhygienic and time consuming in the food industry, and our previous lubrication system had let us down,' explains Russ Woodridge of Rumenco. The new system promises to 'reduce plant downtime and improve tool life,' he says.