Impact Crushers use the energy from a heavy spinning rotor to impact and fracture materials, either by direct impact or autogenous crushing inside the crushing chamber.
In this article we’ll be discussing Keestrack’s Impact Rotor design and how its designed to improve Impact Crushing characteristics.
What Is an Impact Crusher Rotor?
The rotor in an Impact Crusher is essentially a large flywheel that holds the blow bars in place and is used to increase the power and stability of the blow bars which perform 80% of crushing function.
The rotational energy is transferred from the blow bars into the material, fracturing it, and moving material through the chamber until it has been resized to pass by the aprons and exit the chamber.
The Specifics of the Keestrack Rotor
Impact crusher manufacturers use various shapes for their rotors, some are octagonal and some are circular, Keestrack use a square shaped rotor.
The square shape of the rotor allows the blow bars to be offset from the rotational center which places the blow bar closer to the feed material entrance with a higher likelihood of a direct 90° hit.
The physical size and mass of the rotor plays a significant role in the Impact Crushers performance, a heavier and larger rotor means there is more time and space for strikes and a lower rpm is needed to achieve the same force of the strike.
By increasing direct strikes, time and space between strikes and a lower RPM, the Impact Crusher with these rotor characteristics will have reduced wear and better feed material capability and an overall lower cost to run.
The square rotor shape, placement of the blow bars and extra void in space at the front of the blow bar allows material to fall directly in front of the blow bar aiding a cleaner more direct impact and better strike angles to move material through the crushing chamber.
The 90° strike angle aids moving material into and past the aprons, increasing cubical shaping ability, throughput potential, and reducing material hitting the top of the blow bar and not efficiently making its way through the crushing chamber.
More accurate and direct hits against the blow bars ultimately enhance performance, but it also improves the utilization of the blow bars, the offset placement allows the front face of the blow bar to be given a larger void in front of it allowing a larger contact face area and thus a larger amount of the blow bar to be used before it needs to be flipped or replaced.
A heavier rotor has many benefits, more mass means more inertia and energy. Once a heavy rotor is spinning it requires more resistance to slow it down, so maintaining its rotation during crushing can be more efficient as material has less of effect on a heavy rotor than it does on a light one, even if a small rotor is spinning faster. The better energy expenditure and usage mean that a heavier rotor can do more work effectively.
With material spending less time in the chamber before passing the aprons and a slower rotor speed designed for direct strikes of material, blow bars can be more effectively used and process more material before changing. The rotor itself will wear over time, which is the nature of any type of Crushing Equipment. Keestrack’s rotor design differs from most types by including replaceable wear plates in areas most prone to wear over time, especially near the blow bars and strike areas.
Keestrack’s uniquely designed rotor is heavier, requires less rpm to pass material and reduces time material needs to spend in the chamber before it’s sized and passes the aprons. This means an operator can benefit from increased blow bar and wear part life, a lower fuel cost to run and higher throughput of correctly sized cubical material.