Centralised lubrication systems both reduce costs and extend component life by applying precise amounts of lubricant at controlled intervals. Matt Preston of SKF explains how they work.
It seems inconceivable that a hugely expensive piece of machinery could fail due to poor maintenance of a single badly lubricated component or bearing, but the problem is only too prevalent. Around half of all bearing failures are linked to a single issue: lubrication. This can take a number of forms: insufficient lubricant causing the bearing to run ‘dry’ and overheat; excessive lubrication causing damage to seals; and contamination, whether by air, moisture or dirt particles, which soon leads to bearing damage and, ultimately, premature failure.
Protection with the correct lubricant ensures that damage is minimised. Correct selection also means that bearings run with the most appropriate lubricant for the environment they operate in. Even with this in place, machines must be lubricated with enough of this lubricant to keep everything running smoothly. This is where automated lubrication systems come in. Rather than relying on maintenance staff to deal with every lubrication point, which for many machines requires them to be shut down for health and safety reasons, machines can be fitted with systems that replenish every point they are connected to while the machine is in operation. This applies equally to many environments – from machines in a factory to off-highway vehicles.
As well as being more efficient, centralised lubrication brings another critical advantage: it can prevent over-lubrication, which can be as harmful as under-lubrication.
The simplest automated system is a single-point lubricator, dispensing everything from chain oil to food-grade grease. It is typically either gas-driven or electro-mechanical. Some units use a re-placeable cartridge while others are disposable – the SKF System 24 LAGD series and SKF Automatic Lubricant Dispenser TLMR series, for example.
The next step is implementing progressive lubrication systems such as SKF ProFlex and Lincoln Quicklub which dispense set amounts of lubricant while the machine is operating. The grease flow created by the pump is measured by progressive metering devices and distributed to each bearing according to their individual needs. It is a simple and inexpensive way to automate the lubrication of machinery bearings, pins and bushings.
For larger machines, with long lines and harsh operating conditions, dual-line systems are preferred. Examples of these are SKF DuoFlex and Lincoln Helios, and they are used in applications from heavy industry, metalworking plants, pulp and paper, sugar mills, mineral processing and cement factories. These systems – which use two main lines that are supplied alternately with lubricant – are ideal for multiple lubrication points, often in their hundreds, over long distances, and are extremely reliable with high viscosity greases. There are more variants, depending on the complexity and demands of the application. Some larger systems require a multi-line lubrication system, which supplies lubricant to lube points without an extra metering device – as each lubrication point has its own pumping outlet. This is aimed at demanding applications in the oil and gas sector and heavy industries, such as mining.
Other equipment such as machine tools require very small and accurate amounts of lubrication, using low viscosity lubricants due to the high speed nature of many of the components. These single-line systems – such as SKF MonoFlex or Lincoln Centro-Matic – are easy to install, available as pre-set or adjustable models and suitable for most lubricants. They also have the ability to pump long distances and continue to operate within a wide temperature range.
Lubrication is a critical and time consuming maintenance procedure. When done properly, it cuts the cost of maintenance, lengthens machine lifetime and prevents unscheduled shutdowns. The procedure can be further improved through automated lubrication, which ensures more accurate lubrication – through measured dosing – while at the same time freeing up capacity for busy maintenance staff.
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