The largest New Zealand gas-fired thermal power station continues to use no-swell self-lubricating Vesconite Hilube bearings in its cooling water feeder pumps.
The power station did a full refurbishment of these pumps in December 2022 and installed Vesconite Hilube bearings, which currently have a life of nine years in the application.
Vesconite Bearings’ association with the power station and its cooling water feeder pumps goes back to 1996, when the first batch of its bearings was installed, which overcame problems caused by the interruption of process water.
Before the Vesconite Hilube bearings were installed, the water supply to the pumps was occasionally interrupted by seaweed blocking the inlets. A “no cooling water” alarm sounded when this happened but the pumps could run dry for up to 45 seconds before they stopped. The previously installed rubber bearings would then often overheat and be severely damaged. This could occur before the pumps were shut down.
In its search for a solution, the power station first tried replacing the rubber bearings with an elastomeric material widely used for pump bearings. However, this material wore the expensive 316L stainless steel shafts. This proved more costly than the bearings, was more difficult to repair and entailed additional downtime.
The bearings were then replaced with Vesconite Hilube. The pumps fitted with Vesconite Hilube bearings showed no bearing or shaft wear much to the amazement of the engineers concerned.
In November 1996, the Chief Engineer committed to using Vesconite Hilube bearings for these pumps since internal lubricants in Vesconite Hilube make this an ideal material for pump bearings where there is the possibility of a dry start or an interrupted flow during operation.
At this power station, the installed running clearance was also much closer for the Vesconite Hilube bearings than was possible with the original rubber cutlass bearings. The benefit was that the impeller did not run on the casing and, as a result, the pumps were more efficient in their pumping ability and power consumption.
“We are pleased that Vesconite Hilube continues to be used in this application,” comments Vesconite New Zealand’s Eddie Swanepoel.
“Vesconite Hilube is a far better alternative than traditional pump bearing materials, many of which melt down or burn within seconds,” he says.