Progressing toward centralized lubrication systems

The reliability of off-highway machinery is constantly put to the test, especially in the construction, mining, and similar industries 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 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, automatic lube-delivery technologies have been introduced specifically for machinery in the off-highway marketplace. 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.

Choosing the right system   

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 (typically NLGI grades 000 to 0) 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 (NLGI grades 1 to 2) 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 (NLGI grades 000 to 2) ideally suit construction machinery, such as hydraulic excavators.

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

Progressive systems at work

In the construction and other rugged industries, progressive centralized lubrication systems have particularly evolved as highly innovative and practical solutions to feed lubricant from a central source to the points on a machine where friction occurs – while the machine is running. Progressive systems additionally equipped with CAN bus technology represent next-generation solutions to control, deliver, and monitor lubricant in real time.

A progressive centralized lubrication system incorporates a piston pump, main and secondary lines, master and secondary progressive feeders, lines leading to the lube points, and cycle switches (sensors). The overarching purpose is to supply lubrication points continuously with metered lubricant while the machinery is in operation and all the bearings are moving.

            In a progressive system, control electronics integrated into the piston pump unit switch the pump on after a preset interval time. The pump then automatically delivers lubricant to the feeders through the main lines for the duration of the contact time. The system’s progressive feeders serve to precisely and consecutively allocate the lubricant delivered by the pump according to a planned ratio and, in this way each lubrication point on the machine receives the exact amount of required lubricant.