Decanter centrifuge and gear box with harmonic drive and associated operating method

摘要

A decanter centrifuge assembly comprises a bowl, a screw conveyor disposed inside the bowl for rotation at a speed different from an angular velocity of the bowl, and a harmonic drive unit including a circular spline drivingly connected to the conveyor. The harmonic drive unit further includes a flexible spline drivingly connected to the bowl and a wave generator disposed in contact with the flexible spline for distorting the flexible spline and enabling a driving of the flexible spline at a rate of rotation incrementally differing from a rate of rotation of the circular spline. The flexible spline has teeth partially meshing with teeth on the circular spline. The harmonic drive additionally has a lubrication system with a skimmer tube for paring lubricating fluid from a pool in an outer casing of the harmonic drive. A shaft coupled to the wave generator has a channel communicating with the skimmer tube. Several spray nozzles communicate with the channel in the shaft and are juxtaposed to respective bearing surfaces of the harmonic drive unit for spraying lubricating fluid onto the respective bearing surfaces.