Abstract
The quarrying industry has a major impact on the environment. The impact arises from direct sources (that is the quarrying operation with attendant noise and dust) and indirect sources (that is electricity usage). To quantify these usages, the quarrying industry in the United Kingdom consumes some 4.8 TW h/year, representing 3 per cent of installed generating capacity. A significant proportion of this usage is attributable to machines known as cone crushers. Cone crushers are large items of plant (up to 3 m diameter) producing, mainly, aggregates for the road-making industry. The British output is currently 230M tonnes per annum, due to rise to 400M tonnes by 2011. The energy costs are currently £240M per annum.
Further environmental issues are raised by the use of manganese steels. A crusher uses, components that can wear away at a rate of 1 mm per hour. If the parts are not renewed at regular intervals machine performance can be dramatically affected and, in the worst case, mechanical damage may occur. The parts are replaced early to avoid damage with a concomitant poor energy utilization.
The paper describes a programme of work intended to address some of these problems. Pegson Limited, a leading manufacturer of crushing plant, in association with Transfer Technology plc and De Montfort University, are co-operating in a project funded by SERC/DTI under the design of high-speed machinery LINK programme, Treatment is theoretical, demonstrating the justification of the funding. A follow-up paper will detail actual savings and contrast them with the theoretical model.
The next generation of crushers will be instrumented with a range of sensors to monitor machine performance. Of especial interest is a novel sensor which monitors the wear of the crushing components The sensors are connected to a knowledge-based system (KBS) to monitor and control performance. The sensors are not reported in any detail due to the pursuance of Intellectual Property Rights. The ideal performance parameters are obtained from another KBS based on rock mechanics and models of wear mechanisms.
The advanced crushers incorporate a simple man/machine interface and make much use of distributed control based on NEC 78K series microcontrollers. Preliminary studies indicate that energy savings of £15M in the United Kingdom (over £400M worldwide) per year are realizable. Further savings of £5M in the United Kingdom (nearly £150M worldwide) per year arise from the optimal use of the manganese crushing components.
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