The high costs of bearing failures continue to plague heavy industrial plants, including steel mills, rolling mills and continuous casting operations. Frequently, these costs are a consequence of the failure to verify that bearings are receiving the proper amounts and types of lube oil or grease via the integration of monitoring capabilities into large, automated lubrication systems.
Without proper lubrication, bearings seldom survive more than 5-10 percent of their potential service life. This is due to multiple factors like corrosion, heat, caustic elements and high shock loads. However, failure to properly lubricate production equipment, particularly at the critical points, can be an even greater cause of bearing failures, resulting in unnecessary downtime and replacement costs.
These critical points include those bearing points that, if not provided the appropriate lubricant at necessary intervals, will cause the most extensive damage to equipment or present risks to plant personnel. Of course, you can’t be sure you are lubricating all these points effectively unless you have accurate monitoring or verification that the lubricant is being dispensed through the pump to the point where it should be injected at proper intervals. Unfortunately, the investments required to install and maintain lubrication systems with monitoring capabilities are not cheap, which discourages many plants from doing so. Even if the systems are installed, they often require frequent and expensive repair or replacement.
The Conventional Approach
The traditional approach for heavy industrial lubricating applications is the conventional dual-line lubrication system. Capable of delivering varied amounts of lubricant, this type of automated system is ideal for lubricating thousands of points over long distances, with lube oil or grease output being controlled individually at each point.
However, there are drawbacks to the standard dual-line system. Because it is composed of multiple one-piece lubrication dispensing blocks (each servicing up to eight points), the entire block most be replaced whenever a single lube point fails, resulting in added time and labor to the cost of a replacement block.
Even more significant to many applications is that critical-point monitoring or verification is very expensive with standard dual-line systems. In large systems, it can cost thousands of pounds to monitor a single bearing point.
The latest dual-line lubrication systems incorporate a modular design, which can help lower monitoring investments and simultaneously reduce bearing maintenance and replacement costs. With these systems, it is no longer necessary to disconnect supply or discharge valves to change out a non-working section. When valve replacement is required, only the piston section is replaced rather than the entire valve block.
In order to meet the largest system requirements, these designs also permit the creation of dual-line valves with an infinite number of outlets, which is ideal for the steel, cement, pulp and paper, mining and other heavy industries. Essentially, users can tap into the dual lines anywhere and insert a dual-line valve, enabling critical lubrication points to be grouped into zones, which allows for greater design flexibility.
The new modular systems come in both carbon steel and stainless steel for highly caustic environments. They can also provide the flexibility of hybrid systems because they can be easily converted to dispense either grease or oil without having to abandon the original investment in dual-line components.
Long-term Benefits, Short-term Payback
Conventional dual-line systems can cost users more than £100 per point to incorporate monitoring hardware, plus installation expenses. Using the new modular dual-line approach with critical points grouped into zones, users can monitor everything tied to a valve, up to 360 points, for less than £1,000.
In addition, with modular dual-line systems dispensing grease, a significant reduction in lubricant usage is often seen, sometimes as much as 90 percent. This not only saves on grease costs but also virtually eliminates expensive grease disposal.
While the savings in lube oil will not be as great as that of grease, ensuring a constant supply of clean oil in the required amounts and intervals can improve bearing life, which is the biggest payoff of these modular systems.
By Richard Hanley
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