Non Volatile Technologies Pty Ltd SYDNEY   AUSTRALIA   2227     (ABN 96 078 508 264)     Ph:+61 2 9016 4695 "Helping others to have a future assures our own."
	Sand Concentrator - Urethane Trommel Suspension System (1991)
		NVTech CEO (then Engineering Superintendent for Consolidated Rutile) testing of a 1/10 scale trommel wheel to prove to Consolidated Rultile's management that formulae he developed describing the deformation of urethane wheels was accurate and that it was feasible to construct urethane trommel wheels capable of supporting a 70 tonne alluvium trommel. Mainland and South African engineers, at Richards Bay SA, opined this was not possible. Testing proved formulae describing deformation of the urethane were accurate.
	Testing Accuracy of Deformation Formulae		Urethane Pinion Wheel on Gas-Hydraulic Suspension System by Lucas Hydraulics
	The axis of the trommel was tilted so that alluvium, entering the trommel's mouth, would roll downhill. The alluvium, that had not fallen through the sieves in the wall of the trommel, exited into the pond. Before the redesign, previous engineers had achieved positioning of the Trommel by canting the steel driving wheels. This resulted in scuffing and thus caused significant wear on the trommel's riding ring. The solution to this was to use a urethane pinion wheel against the downhill trommel- face. The wheel was held by a gas-hydraulic suspension system as shown. This arrangement not only positioned trommel on the driving wheels without the need to cant them, and thus greatly reduced the wear, it also reported on the thrust the pinion was exerting, through the hydraulic system, on the trommel-face. Because the pinion was held by a gas system, it allowed movement of the pinion and accommodated irregularities in the trommels face plate upon which it ran. Previous engineers had tried to devise methods of holding the trommel in place without canting the driving wheels but all efforts had failed.		1991. Urethane trommel wheels in action. Thanks to the efforts of John Flynn, Dunwich Workshop Foreman (a brilliant tradesman) and John Lyons (a steady engineer and friend). This design saved replacement of the trommel in 1991 at a cost of $1.5 million in labour, materials and lost production. It is now installed on two concentrators on Stradbroke Island. 16 years later, these wheels were still running, avoiding the need to replace the trommels at all. Wear on the riding ring has been negligible. The engineers in the owner company in South Africa have tried on a number of occasions to imitate this engineering solution but have so far failed to achieve the same performance.
		Trommel Wheels in Action
	Copyright © NVTech 2009