The EU’s constantly falling limits for diesel particulate, nitrogen oxides and hydrocarbons for off-road vehicles have challenged the manufacturers of mobile crushers to develop ever more fuel-saving, resource-saving and quieter technologies. Rockster has taken up this challenge and, based on the R1100D Duplex-enabled impact crusher used for the comminution of asphalt, concrete or mixed building rubble to hard natural rock, it has developed a completely new machine for one of the biggest French road construction companies (Fig. 1) – the R1100DE. The customer ordered the Duplex model, so he can switch the crusher unit of the R1100 impact crusher to that of the R1200 jaw crusher within a few hours – and vice versa.
With the goal of further improving efficiency, the Rockster R&D department worked together with a Finnish component manufacturer to develop a parallel hybrid solution. It is based on the electrification, as, unlike diesel motors, electric motors supply full torque from a standing start within milliseconds, can handle load changes more efficiently and enable a precise and steady crusher speed irrespective of the load situation. The permanent magnet technology also promises lower energy consumption, better motor and generator performance, as well as higher power density with lower weight and smaller components. Any peak loads are absorbed with the help of batteries – called Powercaps – that temporarily store energy. Consequently, consumption and, thanks to use of almost wear-free electric motors, maintenance costs fall. With the deployment of this machine technology, it is possible to save up to 16 000 litres diesel per year.
To combat the frequent load peaks and severe environmental job conditions, Rockster made high demands on the material used. All electrical components are water-cooled and comply with the IP65 standard. They are specially designed for use in mobile machines and suitably protected against dust, dirt and water as well as being resistant to vibrations and strong temperature variations.
The Rockster R1100DE is equipped with new variable pumps for the machine hydraulics which only supply the actually required oil flow. In this way, losses are reduced, fuel saved and a steadily high material handling rate is maintained at low and varying diesel motor speed. With the new control system, all values can be easily checked, carefully devised error messages facilitate fast detection and remediation of any faults and easy operation improves efficiency in training and application. Other technical innovations concern the control system to regulate utilization of the crusher in respect of the diesel motor speed and material handling rate as well as the hydraulic overload protection of the impact rockers used instead of pressure springs. As a result, less oversize is produced and there is greater protection against inappropriate feed materials that could disrupt operation.
The return system consists of a two-part return or stockpiling belt. Dismantling for transport is therefore no longer necessary. In addition, a possibility exists to operate the crusher in a closed circuit with 100 % defined final grain as well as for use as a stockpiling belt with a throw-off height of around 4 m. The R1100DE can also be ordered with optional mains connection for operation just with electricity. As a result, further savings are possible, however, power supply is not always guaranteed at off-road job sites.
The crusher system combines improved environmental compatibility with higher cost efficiency. The new crusher can be used in mobile applications like the R1100D driven by a diesel motor. Despite the innovations, the dimensions did not hardly change in order to keep transport costs low (Fig. 2).