Lubricating the parts others cannot reach

Selecting the most appropriate lubricant or grease for a bearing, engine or gearbox is critical to overall system reliability, efficiency and maintenance costs, writes Dean Palmer A new industrial lubricant has been developed that is outperforming established well-known brands in independent wear and weld load tests by a staggering 3.5:1. The independent tests were carried out by Tribologic, part of the School of Mechanical Engineering at the University of Leeds on the new lubricant, Ferrosol, manufactured by Bilt-Hamber. Ferrosol is suitable for use on a variety of metals and composites and is designed to penetrate close tolerances, free rusted parts, displace water, restore electrical circuits and provide corrosion protection in a wide range of industrial and consumer applications. Ferrosol can even be used for the removal of gums, adhesives, wax and tar from most surfaces including automotive finishes. The lubricant can withstand extreme pressures and has low surface tension properties so it is ideal for penetrating and lubricating awkward, difficult to reach moving parts. A typical example offered to Eureka was an injection mould ejector pin, which, when lubricated with Ferrosol, showed high levels of resistance to wear and binding, therefore reducing expensive downtime. But the lubricant could also find favour in heavy industrial applications such as winches, chains and load bearing pivots and unions, even though high stress applications such as these are usually deemed unsuitable for conventional penetrative lubricants. Its anti-wear properties means that Ferrosol is also suitable for drilling, tapping and reaming where useful tool life can be increased. But there's more. The lubricant is also environmentally friendly, containing no silicone, PTFE, molybdenum disulphide or chlorinated solvents and so can be used safely in areas such as automotive body shops, where there is a risk of paint defects when using fluids containing silicone. Lubrication cycles have been extended at five Thames Water sites in Edinburgh, following the company's switch to using lubricants from Rocol. Thames Water had been using 50 different lubricants from a variety of suppliers on each of its five Edinburgh sites, which was placing a burden on busy maintenance staff. Rocol was invited to carry out an on-site diagnostic lubrication survey, aimed at helping Thames streamline the number of products and suppliers to meet its lubrication needs. The survey demonstrated that, by standardising its lubrication usage and specifying high performance Rocol lubricants, Thames Water could extend re-lubrication intervals, reduce equipment downtime and cut maintenance labour costs. The change was made and Thames Water now uses only 12 different Rocol oil and grease products across the sites. Stewart Gray, maintenance manager at Thames Water told Eureka: "The installation of Sapphire Unilube units across the five sites has extended lubrication cycles by three times and the Rocolcare survey enabled us to rationalise lubricant usage, eliminate mistakes and reduce stock costs... [and] it has allowed us to maximise the use of our manpower, reduce expenditure and minimise unscheduled downtime on machinery." Like most engineered products, lubricants are affected by environmental legislation. Steve Travell, technical services advisor for Castrol Industrial, told Eureka that design engineers of hydraulic systems need to consider specifying zinc-free oils: "Can it be that for many engineers the extra cost of zinc-free oils still outweighs the benefits, especially when price is often the only consideration when specifying conventional hydraulic oils? "But times are changing. Even if the environmental lobby isn't exactly winning the day, added value benefits [of zinc-free oils] such as performance and reliability are increasingly being acknowledged." Travell explained that most conventional hydraulic oils use a high-zinc additive package, which has provided a "satisfactory" performance for many years in anti-wear applications. "However, they are not always acceptable in some of today's higher performance pump applications and users should check with the manufacturer. Low zinc additives do provide a compromise between the anti-wear requirements of vane pumps and the anti-corrosion requirements of piston pumps." He also said that whilst there are specific bio-degradable and vegetable hydraulic oils available that will reduce the impact on the environment, "these are currently more expensive; so industry still widely uses the conventional mineral based lubricants. This, despite the fact that the elimination of heavy metals in oils such as Castrol's Hyspin ZZ [zero zinc] range greatly reduces environmental impact through accidental spillage, misting from air lubricators, disposal treatments and burn off from swarf smelting furnaces." Another key advantage of zinc-free oils is their ability to operate in fine clearance spool valves where cleanliness is critical. According to Travell, hydrolytic stability is a problem faced by all systems made from metal as they will inevitably suffer corrosion if exposed to water, even if this water exists as only droplets within oil. "Whilst all hydraulic oils may suffer water ingress through contact with wet air, coolant ingress or process water contamination, conventional zinc additive oils do tend to suffer more, due to the reaction of the zinc additive and water forming deposits and gels," he explained. This is major concern for filtration, where filter blockages can either cause oil starvation leading to system failure or, if oil vents through a relief valve, can deliver unfiltered oil to critical areas. Radial pumps can also be affected as the vanes of the pump are reliant on unimpeded movement and gelling can jam them, reducing pump efficiency and increasing wear. In food manufacturing, lubricants are also critical. A food processing manufacturer (that wishes not to be mentioned) was recently using expensive ester-containing extreme pressure (EP) synthetic oil in a custom built gearbox application and ran into difficulties as the oil was not approved for use near foods and the gearbox was being used on meat slicing machines. According to RW Greeff, UK distributor for Dow Corning's Molykote oil range, the gearbox had been developed by the company and featured helical steel gears. The gearbox experienced higher than normal operating temperatures between 71°C and 82°C. Having performed numerous tests on available food-grade gear oils, the manufacturer found that none could meet the challenge set by the demanding operating conditions. For almost four years the company used the ester containing EP synthetic oil. The gearbox also broke down relatively quickly, requiring maintenance staff to perform changeovers every 30 days. And almost half of the slicing mechanism had to be disassembled to facilitate this. Also, if the oil was not changed frequently enough, the non food-grade oil might also lead to varnish deposits which would significantly shorten gearbox life and require premature rebuilding. The food manufacturer switched to Molykote Gear oil (L-1115FG), a synthetic oil made by combining smaller molecular 'building blocks' to meet targeted specifications and to minimise impurities. The FDA-approved oil contains polyalphaolefin and can withstand high and low temperatures, reduces volatility and provides compatibility with equipment designed for use with mineral oils. According to RW Greeff, its food customer, which has more than 1,000 meat slicing machines, now schedules maintenance on the gearbox every 90 days. And friction within the gearbox was prevented to such an extent that the operating temperature under production conditions dropped by 11°C representing a 13 to 15% improvement compared to the EP synthetic oil previously used.