CT Logo

The reliability of construction and mining equipment is constantly put to the test, where equipment often must operate in harsh or extreme conditions. Mechanical components are threatened by friction and other elements, which can cause wear or damage, leading to a potential failure. As a first line of defense, proper lubrication of rolling bearings, pin & bush and all the connected points on machinery can help optimize performance, productivity, and longevity in service. How, when, and how much lubricant is applied, however, can become causes for concern.

In the case of lubricating points manually, pitfalls loom. Points can become over- or under-lubricated (unacceptable either way), the application of lubricant may be sporadic or inappropriately timed, and the inaccessibility of lubrication points can become an issue. From there, operations may slide downhill due to premature failure of equipment.

As an alternative to manual lubrication, centralised lubrication systems, sometimes also referred as automatic lubrication systems, have been introduced. In particular, automatic centralized lubrication systems in different configurations have gained significant ground by enabling the right lubricant to be supplied at the right time and at the right lubrication point without manual intervention.

A centralised lubrication system is key in achieving peak performance from any operating equipment whether it is a dump truck, mobile crusher, earth mover or static processing plant. 

In a study conducted by a major component manufacture, it was found that over 60% of bearing failures were the result of inadequate lubrication and bearing contamination. The ramifications are, unsurprisingly, costly and can cause massive disruption to production site.

Not only this, manual lubrication can be inconvenient; stopping a machine at regular intervals to lubricate bearings is expensive, increasing both downtime and reducing manpower. As a result, businesses will never be able to maximize the performance and value of their equipment.

Too much lubrication can potentially create a safety or environmental hazard, while too little lubrication causes bearing friction and wear. The use of centralised lubrication systems eliminates the 'feast or famine' conditions associated with manual lubrication.

A centralised lubrication system applies smaller amounts of lubricant frequently while the machine is in operation. This, effectively, keeps bearings in the Optimum Lubrication Zone.

Applying lubrication to a bearing is far more efficient in smaller quantities at shorter time intervals with the bearing in motion. This formula is near impossible to maintain with manual greasing.

With a centralised lubrication system installed on a machine, all bearings are lubricated regardless of location. Lubrication only occurs when the equipment is in operation, ensuring even distribution and maintaining a level of lubricant around the bearing contact surface areas. This leads to a number of benefits, including: lower energy consumption due to less friction; reduced wear on the components resulting in extended bearing life; fewer breakdowns; lower replacement and maintenance costs; and increased productivity.

A centralised lubrication system also eliminates a number of safety hazards, such as climbing over equipment and/or entering confined spaces to access bearings requiring lubrication.

Centralised lubrication systems were introduced in the mid-1930s and since then much research has focused on resolving the flow issues of various lubricants, e.g. delivering grease properly to its designated points. Advances in technology have created today's centralised lubrication systems featuring precise delivery methods for a wide range of applications.

Today's advanced centralised lubrication systems distribute a measured amount of lubricant to a specific location at specific times through the use of the programmable controllers, timers and lubrication pumps, distribution blocks, metering units or injectors.

When delivering lubricants to bearings, the lubrication pump is activated by the controller. This creates pressure and distributes the grease/oil to the system distribution block or injector, which is pre-set to deliver a specific amount of lubricant at a specific time interval. Lubricant flows through the grease lines and distribution block/injector, which, in turn, feeds grease/oil into the bearing.

A pressure switch can be incorporated in the system to deactivate the pump once the lubrication cycle is completed. In the last step of some types of centralised lubrication systems, a unit can detect any lubricant pressure remaining in the grease line, which is then delivered back into the reservoir.

The latest technological advancements have seen many products available for controlling and monitoring centralised lubrication systems. Distribution blocks/injectors, grease lines and lubricant reservoirs are now commonly monitored by visual and/or audio signals. For example, an alarm is sent when an undesirable flow pattern exists or when the lubricant reservoir is low.

The size of a machine, type of required lubricant, number of lubrication points, and other factors will guide initially in choosing the most viable centralized lubrication system for an application. Among the more commonly specified systems that can be evaluated and then specified as appropriate:

• Single-line lubrication systems for semi-fluid grease are primarily designed for small- to medium-sized construction equipment. Lubricant volumes from 0.01 cc to 2.5 cc are dispensed to the individual lubrication points on each lube pulse. The right amount of lubricant is delivered, regardless of back pressure.

• Dual-line lubrication systems for semi-fluid grease and hard grease provide solutions for medium-sized and larger machines with many lubrication points, long lines, and operating in harsh conditions, such as equipment used in the mining industry.

• Progressive lubrication systems for semi-fluid grease and hard grease ideally suit construction machinery, such as hydraulic excavators.

For OEMs, such systems can add value and sharpen the competitive edge