Spiders that were manufactured from Vesconite continue to be used to support the shafts of two borehole pumps installed on a Meyerton, South Africa, vegetable farm.
Some 28 spiders were manufactured at Sima Turners, of Johannesburg, South Africa, for the owner’s farm some 15 years ago and these are still functioning to support two borehole pump shafts that reach 78m into the ground.
Farm owner Roland Gaberthuel designed the pump configuration that is able to pump 2-million li-tres of water a day.
He chose Vesconite as a replacement for bronze spiders since bronze was deemed to be heavy and likely to be stolen for its resale value should they be out the borehole during maintenance.
The spiders have an outer diameter of 100mm and a shaft of one inch, with 8mm radiating spokes – the spider’s legs that give the part its name.
Vesconite has often been used as a line shaft bushing that supports borehole pump shafts.
Its self lubricating properties and good wear characteristics mean that it is a suitable for the wear mating surface.
However, in this application, the spider is used to centralise the shaft.
Gaberthuel notes that the Vesconite is likely to last as long as the pumps, and it is expected that there will be no need to replace the spiders.