A full range of robust vertical shaft impact crushers has been added to the product offering of Johannesburg-based Osborn. Manufactured in the USA by sister company KPI-JCI, these versatile, low-maintenance vertical shaft impactors (VSIs) have proved their mettle in the USA, Canada and Europe. The VSI has the advantage of fracturing stone through impact, which typically creates a more cubical product vs. the cleavage fracture from a compression crusher.
A unique feature of KPI-JCI’s vertical shaft impactors is their versatility. The same machine can be configured to run in standard, semi-autogenous and fully autogenous modes. This is what really sets them apart from other VSI crushers on the market. Customers can configure their machines according to their needs, to suit their applications. This versatility provides for significant cost savings, since one VSI can effectively be turned into three different machines, with some simple adjustments and changes within the internal components. Compared to a standard VSI, a semiautogenous VSI will save about 33% in wear costs, and a fully autogenous VSI will save an additional 33%.
The KPI-JCI VSI crushers deliver highly consistent end products, are available in both stationary and portable configurations and crank out up to 500 tph production output. They are best applied in tertiary and quaternary applications and various secondary applications. Rock fed to the crusher’s accelerator mechanism (table or rotor) is flung outwards by centrifugal force against the stationary anvils or hybrid rock shelf for free-body impacting. The proper chamber configuration is application dependent. As a fully autogenous crusher, this VSI features a rotor and hybrid rock shelf.
Rock-on-rock crushing occurs with variable reduction ratios between 6:1 and 3:1 achievable. As a semi-autogenous crusher, with rotor and anvil, the crushing chamber has an autogenous rotor and standard stationary anvils for specialised crushing and problem materials. With feed sizes of 38mm to 51mm, reduction ratios between 8:1 and 3:1 are achieved. With a standard configuration, featuring shoe and anvil, with a maximum feed size of 152mm, variable reduction ratios between 10:1 and 3:1 are possible.
Precise Gradation Control
Major crushing advantages of the KPI-JCI vertical shaft impactor include precise gradation control; the production of chips and asphalt aggregates fines; and compliance with cubical and fracture count specifications for today’s tight specification requirements in asphalt paving. The autogenous configuration of the VSI produces more in spec material in a single pass than that of more conventional compressive crushers. The autogenous rotor and hybrid rock-self design delivers proper internal crusher geometry for maximum production at the lowest cost.
Other noteworthy features of the crushers include feed tube inspection doors and a unique, low-maintenance lubrication system. The externally adjustable, reversible and replaceable feed tube allows for quick, easy adjustment though the Inspection door located on the top lid for easy access to the impact chamber. Bearing housing on this VSI runs in an oil lubrication system, so there is little to no maintenance on bearings and housing, and no hassle with greasing every eight hours, as required with other machines.