Road Transport

New horizontal shaft impactors join Australian market

Rocktec Australia has formed a partnership with Crushrite CC, in South Africa, to manufacture a comprehensive range of horizontal shaft impactors under licence. Although Crushrite is a relatively young company, the design team has many years of experience in the field of impact crushing. The machines are innovative while incorporating features based on a wealth of field experience.
The extensive range comprises crushers built for primary and secondary duty, as well as tertiary/quaternary sand impactors. It has been designed with state-of-the-art computer technology, complementing the extensive expertise of the design team in order to provide the best solutions to many specific applications, and a continual and ongoing development programme that ensures that the needs of every client are met, and will continue to be met, well into the future.
These machines are suited to static plant operations, as well as mobile/portable operations, either wheeled or tracked.
The primary and secondary ranges incorporate seven sizes of crushers with capacities from 30 tonnes per hour to in excess of 350 tph, depending on how the machines are configured. The general design follows the Andreas principle, incorporating heavy rotors to generate maximum kinetic energy, mounted on oversised shafts.
A unique feature of the design is the standard use of a third crushing apron to maximise power utilisation and increase the reduction ratio; the third apron reduces the work load on each apron, with a small increase to the crusher power requirements, but not to the same extent as a grinding path. It has an effect similar to the grinding path in limiting the oversize in the product, but it is not as power consuming and, while a finer product ensues, it is not high in unwanted superfines. The wear rate of apron liners is significantly lower than that experienced with grinding paths. Furthermore, adjustment of the apron, and replacement of the wearing parts is less expensive, easier and quicker than with a conventional grinding path.
The concept of ease of maintenance and replacement of wear parts is fundamental to the Crushrite principle, eg the bearing housings are built using machined thick wall tube to reduce costs, compared with being machined from a solid billet, and not prone to cracking as cast versions are. The design enables bearings to be readily pushed out for replacement, due to the removable end caps. 
User-friendliness is a continued theme with wear parts as 80 per cent of side liners across the whole range are identical and are in Hardox plate, drilled and tapped to secure in place with standard HT bolts. The blow bar design (four row rotors standard, six row rotors available on larger sizes) uses the reversible Hazemag style, therefore availability is assured ? standard supply would be Hadfield manganese for less abrasive feed, or Martensitic steel for more abrasive applications. Impact plates are also made of Hardox wear resistant plate.
Access into the machine is achieved by opening the hydraulically operated hinged top housing of the crusher to enable any component to readily be lifted out. As the complete housing hinges away from the machine, access is greater than in the majority of other brands. The same hydraulic unit (electric or manual options are available) is used for adjustment of the impact aprons.
For production of crushed rock fines and manufactured sand there is a range of two row rotor top feed, high-speed machines (generally tip speeds in the region of 60-65 metres per second) with capacities from 60 tph to 120 tph. Typically they will accept feed to 50?60mm in size and reduce this to 100 per cent minus 20mm in one pass, with a high cubicity and, due to minimised recirculation, much lower minus 75? being produced than, for example, a VSI crusher. These sand impactors are also able to crush relatively fine feed economically and successfully ? typically, surplus 5?10mm feed can be used to produce additional sand when required. The design and manufacturing features of these machines are similar to the primary/secondary ranges, with both halves of the top housing hinged, and side liners held in by wedges.
These machines have been extensively field tested in South Africa and neighbouring countries in a wide variety of applications, eg:
  • For aggregate and sand production from limestone, basalt and granites, where the excellent shape and low superfines prove to be a valuable asset.
  • In pre-milling applications, where the high reduction ratios significantly reduce power requirements for the mills.
  • Coal crushing.
  • For liberating diamonds from Kimberlite, the Crushrite design has consistently proven to yield higher returns.
  • The crushing of chrome ore where, despite the high abrasiveness, economic operation is feasible due to the high efficiency of crushing, combined with low capital cost, in comparison with alternatives. 
  • Slag and rubble crushing and in a variety of other demolition waste and similar recycling applications.
Having spent many months researching a suitable partner for a range of horizontal impact crushers, the Rocktec team has concluded that this is a good range of well designed and engineered crushers that is well suited to the Australian mining and quarrying industries. A full spares and service support operation is being established at the Rocktec facility in Yatala, near Brisbane, in order that its customers can be confident of getting the service they demand, when they need it, from a well-established and highly reputable company.
For further information about Crushrite, contact Rocktec Australia,
Source: Rocktec

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