Select Page

From Keith Macaluso
International Business Development Manager

T.F. Hudgins Lubrication Products, Allied Reliability

An oil refinery in the Northeastern part of the U.S. was experiencing failures on a minimum of two gearboxes each year. The ensuing losses were catastrophic, with the output-shaft bearings dropping into the gearing, resulting in a $50,000 repair on each gearbox. Excessive water contamination in the gearboxes caused corrosion, rust, and sludge formation in the gearbox reservoirs. Here, Keith Macaluso of T.F. Hudgins discusses the solution and its one-year payback.

Fig. 1. Four-cell cooling tower.
(Source: T.F. Hudgins, Houston, TX)

The client decided on an oil mist system with a bulk-oil fill and drain system for each gearbox. The gearbox was converted by removing the oil pumps that would force contaminated gear oil up to the bearing. The output-shaft bearing was converted to pure oil mist lubrication, with the gearbox now purged with oil mist. The gearbox was supplied with synthetic lubricant, as was the oil mist system (Fig. 2).

Fig. 2. Typical cooling-tower gearbox setup with
oil mist to the gearbox and electric motor
and bulk-oil fill and draining.
(Source: T.F. Hudgins, Houston, TX) 

After one year of operation, there were no failures, and this success continued for many years. The payback on this complete system was less than one year.

Key improvements documented for this success included:

1.  Elimination of a minimum of two gearbox failures each year.

2.  Safety improvement, no entry permit for two mechanics, and locking out of motor
and scaffolding inside the cooling tower cells.

3.  Environmental improvement; no oil-spill risk with draining and filling gearbox.

4.  Crane for removal of gearbox and installation of the repaired gearbox, with required
watch personnel on the ground.

5.  Winter windmilling in reverse had been an issue. Oil mist now coats all internals
with clean, fresh oil.