The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Erik Hulthén - One of the best experts on this subject based on the ideXlab platform.
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Importance of Crusher control and cloud computing process monitoring of Crushers
2019Co-Authors: Gauti Asbjörnsson, Erik Hulthén, A. Bolander, Magnus EvertssonAbstract:The main task of a Crusher control system is to keep production on a desired level while simultaneously protecting the Crusher from overload and fatigue failure. A stable production can be achieved through control of the Crusher's closed side setting (CSS), which implies compensation of the wear of the Crusher liners. A further objective is to provide with the possibility to optimize operational performance and utilization. For an efficient system the sampling rate needs to be sufficiently high and the control and optimization algorithms need to be robust. In addition, and equally important, configuration of the electrical cabinet and wiring must be able to withstand the harsh environment over time. Modelling and simulation of cone Crushers have been on-going at Chalmers University of Technology during the last 25 years. With time the research has expanded to include several different aspects of cone Crusher operation, design optimisation, real-time control and product yield optimization. As a consequence, a strong need for dedicated control possibilities of cone Crushers have risen. The requirement for precise control led to the development of a new system for cone Crusher control which was named Crusher Control Unit or CCU. The system has been further developed by Roctim to provide an independent, modular and flexible development platform for different Crusher types. A unique feature is that the CCU can be retrofitted to both Hydrocone type of cone Crushers as well as to Symons type independent of brand or age of the Crusher. In order to remotely monitor the Crusher performance and retrieve data from the CCU a cloud based solution has been developed.
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Impact of Feeding Position on Power Draw and Size Reduction in a Cone Crusher
2018Co-Authors: Albin Gröndahl, Erik Hulthén, Johannes Quist, Gauti Asbjörnsson, Carl Magnus EvertssonAbstract:The power draw of cone Crushers, used in comminution and aggregates production, is in most cases monitored with too low sampling rate in comparison to the operating speed. This does not give adequate information on the actual operation mode and performance of the Crusher during a full rotation of the eccentric motion of the mantle, leaving variance in the power draw unnoticed. This investigation has utilized a high speed measurement system for power draw on a lab scale cone Crusher in order to identify an induced miss alignment in the feed, which is a common operation phenomenon, and the consequences of it. The results show that variations in the feeding alignment can be diagnosed and identified using only power draw measurements and that there are possibilities to use the approach for future control systems to improve fatigue life, operating efficiency, production yield and liberation in comminution processes.
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A Novel Approach to Cone Crusher Feeding using High frequency Power Draw Measurements
2017Co-Authors: Marcus Johansson, Magnus Evertsson, Erik HulthénAbstract:The cone Crusher is one of the most widely used crushing machines in comminution circuits. The performance of the machine is heavily dependent on how it is fed. The performance of cone Crushers is usually quantified by the three measures; throughput, power and particle size distribution. In this research, an adjustable feeding nozzle is controlled using an adaptive algorithm to position the feeder nozzle for improved feeding conditions. By processing high-frequency power data, an estimation of the power variance can be obtained, which is in this work studied to improve the feeding conditions of the cone Crusher. Step responses as well as steady state power draw is compared and used to develop a new algorithm. An adjustable nozzle have been built and evaluated in a laboratory environment. The results are also compared to using a stationary feeder. The laboratory tests show promising results for applications where trickle feeding of cone Crushers is preferable.
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Investigation of High Speed Cone Crushing Using Laboratory Scale Experiments and DEM
2017Co-Authors: Marcus Johansson, Carl Magnus Evertsson, Johannes Quist, Erik HulthénAbstract:Cone Crushers are commonly used in secondary and tertiary crushing stages in comminution circuits. A multitude of factors and variables influence the performance in terms of throughput capacity, size reduction, power draw and wear. Crushers are normally installed and operated at a fixed eccentric speed setting. By installing variable frequency drives and realtime optimization algorithms Hulthen and Evertsson have shown that the eccentric speed can be used as a variable to optimize the yield and improve the performance. However, the influence of eccentric speeds above the normal operational range has been scarcely reported on in the literature. This paper aims at reporting on the result from an exploratory study where experiments and simulations have been used to evaluate cone Crusher operation at high eccentric speed levels ranging from 10-40 Hz. A laboratory Morgardshammar cone Crusher has been refurbished for the purpose of the study. A preliminary set of experiments have been performed where results showed that the chamber geometry has a vital importance. The same behaviour as observed in the experiments was also further understood by using DEM simulations leading to the design of a new chamber geometry. The new chamber design have been evaluated using DEM at four eccentric speeds and two different close side settings. The rock model has been calibrated by single particle breakage experiments and is based on the bonded particle model. The product particle size distribution has been estimated by image analysis of the bonded cluster discharge. The work addresses and shows results relevant to three areas in comminution and engineering research; Simulation driven design, DEM modelling, Cone Crusher theory.
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Real-Time Optimization of Cone Crushers
2017Co-Authors: Erik HulthénAbstract:Cone Crushers are used in the mineral, mining, and aggregate industry for fragmentation and production of rock materials. Cone Crusher control systems are widely used for machine protection, wear compensation and, to some extent, increasing production. These systems ordinarily focus on the Crusher and not the yield of production process. In this thesis real-time optimization is explored to the control of eccentric speed and on-line CSS adjustment based on information from the process. The objective is to develop theories, models, software and hardware that enable real-time optimization of a single crushing and screening stage. The main hypothesis is that fixed parameters can never be optimal over time because many things in the process vary continuously. The eccentric speed in a cone Crusher determines the number of times a material is compressed and thus the particle size distribution of the product. The speed of the Crusher is usually fixed since speed change by changing pulleys is a labor intensive activity. By applying a frequency converter to the Crusher motor power supply, it is possible to continuously adjust the eccentric speed. The cost for frequency converters has decreased significantly over the last decade. By applying mass-flow sensors to the process, e.g. conveyor-belt scales, the Crusher result can be monitored and the result can be fed back to an operator or a computer. To analyze data from the process and automatically calculate the appropriate value for the Closed Side Setting (CSS) and eccentric speed, algorithms have been developed. The goal for the algorithms is to maximize the product yield in a given moment. The algorithms are loaded into computer systems that can communicate with sensors and Crushers. The developed algorithms are tested and evolved at full-scale aggregate crushing plants. Crushing stage performance increased 3.5% in terms of production yield compared to a fixed CSS when the algorithm was implemented in addition to the existing control system. The algorithm automatically compensates for changes in the feed material and also decreases the need for calibration of the CSS. The crushing stages where the speed algorithm were tested increased their performance by between 4.2% and 6.9% compared to a good fixed speed. In real life however, the performance was increased by almost 20% since an inappropriate speed was selected during installation. As a bonus, on one of the test plants for the dynamic speed, the lifetime of the manganese wear parts increased 27% on the evaluated Crusher, as a consequence of changed Crusher dynamics. In conclusion, real-time optimization has been demonstrated to be feasible and increases the production yield with significantly numbers and should thus be of commercial interest to the industry.
Thomas Gustafsson - One of the best experts on this subject based on the ideXlab platform.
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CCA - On-line optimization of cone Crushers using Extremum-Seeking Control
2013 IEEE International Conference on Control Applications (CCA), 2013Co-Authors: Khalid Tourkey Atta, Andreas Johansson, Thomas GustafssonAbstract:This article demonstrates the ability of on-line optimization of cone Crushers, specifically maximization of the total throughput of the Crusher by adjusting the eccentric speed (ω). The on-line optimization was based on the Extremum-Seeking Control (ESC) approach, which is advantageous when optimizing systems with unknown time varying characteristics. Two types of gradient based approaches are tested in simulation, the traditional Band-pass filters method and a method utilizing the Extended Kalman Filter (EKF). Both methods perform satisfactory, demonstrating the good potential of ESC for online-optimization of cone Crushers. To deal with unwanted behavior of the EKF based approach for situations when the gradient is not correctly estimated, a modification is suggested based on detecting this condition and accommodating for it.
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On-line optimization of cone Crushers using Extremum-Seeking Control
2013 IEEE International Conference on Control Applications (CCA), 2013Co-Authors: Khalid Tourkey Atta, Andreas Johansson, Thomas GustafssonAbstract:This article demonstrates the ability of on-line optimization of cone Crushers, specifically maximization of the total throughput of the Crusher by adjusting the eccentric speed (ω). The on-line optimization was based on the Extremum-Seeking Control (ESC) approach, which is advantageous when optimizing systems with unknown time varying characteristics. Two types of gradient based approaches are tested in simulation, the traditional Band-pass filters method and a method utilizing the Extended Kalman Filter (EKF). Both methods perform satisfactory, demonstrating the good potential of ESC for online-optimization of cone Crushers. To deal with unwanted behavior of the EKF based approach for situations when the gradient is not correctly estimated, a modification is suggested based on detecting this condition and accommodating for it.
Carl Magnus Evertsson - One of the best experts on this subject based on the ideXlab platform.
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Cone Crusher Performance
2020Co-Authors: Carl Magnus EvertssonAbstract:Cone Crushers are used by both the aggregate producing and the mining industry. Both industries are interested in increasing the product quality while at the same time lowering the production costs. Prediction of Crusher performance has been focused on, since crushing is a vital process for both industries. In the thesis a method for prediction of cone Crusher performance is presented. The model is based on the laws of mechanics and constitutive relations concerning rock breakage characteristics. There are some crucial assumptions which are of central interest for the model. The validity of these assumptions has been verified by full-scale tests. The overall size reduction process is a result of several subsequent crushing events. Therefore, the process occurring in a cone Crusher must also be modelled in the same repetitive way. Each crushing event is modelled with a selection and a breakage function. Selection corresponds to the probability of a particle being broken when an aggregate of particles is compressed. Breakage represents the way a single particle is broken into smaller fragments. The appearance of the selection and breakage functions is rock material specific and can be obtained by laboratory tests. The characterization of the fragmentation behaviour for rock materials is done by form conditioned compression crushing tests. Two modes of breakage are possible to achieve in a cone Crusher. The location of the choke level is the criterion which determines the breakage mode. Interparticle breakage is achieved above the choke level while only single particle breakage is achieved below this level. The Crusher model takes the fragmentation behaviour of the rock and feed size distribution into consideration. Moreover, chamber and machine geometry, together with machine parameters such as closed side setting, stroke and eccentric speed, is accounted for. On all occasions continuity of mass is preserved. Three main factors are identified to promote the size reduction process occurring in a cone Crusher. These factors are: breakage modes, number of crushing zones, and compression ratio. The main factors are affected by both design and operating parameters. For a given Crusher, the factors depend on eccentric speed, closed side setting, rock material breakage characteristics and feed size distribution. The main factors provide a fundamental and detailed understanding of how a cone Crusher operates. Any design consideration should be evaluated against these main factors. The model can be used as a simulation tool to assist in the design process of Crushers. Any arbitrary design can then be studied. If a set of simulations is performed for a given Crusher, a Crusher Performance Map is achieved, which in turn can be used when optimizing a given crushing task or a crushing plant.
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Liner wear in jaw Crushers
Minerals Engineering, 2020Co-Authors: Mats Lindqvist, Carl Magnus EvertssonAbstract:Wear in rock Crushers causes great costs in the mining and aggregates industry. Change of the geometry of the Crusher liners is a major reason for these costs. Being able to predict the geometry of a worn Crusher will help designing the Crusher liners for improved performance. A model for prediction of sliding wear was suggested by Archard in 1953. Tests have been conducted to determine the wear coefficient in Archard's model. Using a small jaw Crusher, the wear of the Crusher liners has been studied for different settings of the Crusher. The experiments have been carried out using quartzite, known for being very abrasive. Crushing forces have been measured, and the motion of the Crusher has been tracked along with the wear on the Crusher liners. The test results show that the wear mechanisms are different for the fixed and moving liner. If there were no relative sliding distance between rock and liner, Archard's model would yield no wear. This is not true for rock crushing applications where wear is observed even though there is no macroscopic sliding between the rock material and the liners. For this reason, Archard's model has been modified to account for the wear induced by the local sliding of particles being crushed. The predicted worn geometry is similar to the real Crusher. A cone Crusher is a machine commonly used in the mining and aggregates industry. In a cone Crusher, the geometry of the crushing chamber is crucial for performance. The objective of this work, where wear was studied in a jaw Crusher, is to implement a model to predict the geometry of a worn cone Crusher.
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Impact of Feeding Position on Power Draw and Size Reduction in a Cone Crusher
2018Co-Authors: Albin Gröndahl, Erik Hulthén, Johannes Quist, Gauti Asbjörnsson, Carl Magnus EvertssonAbstract:The power draw of cone Crushers, used in comminution and aggregates production, is in most cases monitored with too low sampling rate in comparison to the operating speed. This does not give adequate information on the actual operation mode and performance of the Crusher during a full rotation of the eccentric motion of the mantle, leaving variance in the power draw unnoticed. This investigation has utilized a high speed measurement system for power draw on a lab scale cone Crusher in order to identify an induced miss alignment in the feed, which is a common operation phenomenon, and the consequences of it. The results show that variations in the feeding alignment can be diagnosed and identified using only power draw measurements and that there are possibilities to use the approach for future control systems to improve fatigue life, operating efficiency, production yield and liberation in comminution processes.
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Investigation of High Speed Cone Crushing Using Laboratory Scale Experiments and DEM
2017Co-Authors: Marcus Johansson, Carl Magnus Evertsson, Johannes Quist, Erik HulthénAbstract:Cone Crushers are commonly used in secondary and tertiary crushing stages in comminution circuits. A multitude of factors and variables influence the performance in terms of throughput capacity, size reduction, power draw and wear. Crushers are normally installed and operated at a fixed eccentric speed setting. By installing variable frequency drives and realtime optimization algorithms Hulthen and Evertsson have shown that the eccentric speed can be used as a variable to optimize the yield and improve the performance. However, the influence of eccentric speeds above the normal operational range has been scarcely reported on in the literature. This paper aims at reporting on the result from an exploratory study where experiments and simulations have been used to evaluate cone Crusher operation at high eccentric speed levels ranging from 10-40 Hz. A laboratory Morgardshammar cone Crusher has been refurbished for the purpose of the study. A preliminary set of experiments have been performed where results showed that the chamber geometry has a vital importance. The same behaviour as observed in the experiments was also further understood by using DEM simulations leading to the design of a new chamber geometry. The new chamber design have been evaluated using DEM at four eccentric speeds and two different close side settings. The rock model has been calibrated by single particle breakage experiments and is based on the bonded particle model. The product particle size distribution has been estimated by image analysis of the bonded cluster discharge. The work addresses and shows results relevant to three areas in comminution and engineering research; Simulation driven design, DEM modelling, Cone Crusher theory.
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A comparative study between cone Crushers and theoretically optimal crushing sequences
Minerals Engineering, 2011Co-Authors: Carl Magnus EvertssonAbstract:Abstract The supply of minerals, ores and aggregates are crucial for the continuous development of today’s society. With a rising world population, growing urbanization, and increasing standards of living, the performance and efficiency of existing Crushers must be improved in order to meet the escalating demand on these products. The current paper thus presents a comparative study between existing cone Crushers and theoretically optimal crushing sequences. Full scale experiments are conducted in order to examine the effects of Closed Side Setting (CSS), stroke, and eccentric speed on Crusher output. The performance of the examined cone Crusher is then compared against what is considered as theoretically optimal. The subsequent analysis shows that significant gains can be made in terms of both product yield and overall capacity by adjusting Crusher operation depending on the conditions at hand, e.g. increasing the CSS while maintaining the same stroke or decreasing the eccentric speed. It is also shown that a mixture of breakages modes is more optimal than the sole application of one optimized breakage mode.
Khalid Tourkey Atta - One of the best experts on this subject based on the ideXlab platform.
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CCA - On-line optimization of cone Crushers using Extremum-Seeking Control
2013 IEEE International Conference on Control Applications (CCA), 2013Co-Authors: Khalid Tourkey Atta, Andreas Johansson, Thomas GustafssonAbstract:This article demonstrates the ability of on-line optimization of cone Crushers, specifically maximization of the total throughput of the Crusher by adjusting the eccentric speed (ω). The on-line optimization was based on the Extremum-Seeking Control (ESC) approach, which is advantageous when optimizing systems with unknown time varying characteristics. Two types of gradient based approaches are tested in simulation, the traditional Band-pass filters method and a method utilizing the Extended Kalman Filter (EKF). Both methods perform satisfactory, demonstrating the good potential of ESC for online-optimization of cone Crushers. To deal with unwanted behavior of the EKF based approach for situations when the gradient is not correctly estimated, a modification is suggested based on detecting this condition and accommodating for it.
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On-line optimization of cone Crushers using Extremum-Seeking Control
2013 IEEE International Conference on Control Applications (CCA), 2013Co-Authors: Khalid Tourkey Atta, Andreas Johansson, Thomas GustafssonAbstract:This article demonstrates the ability of on-line optimization of cone Crushers, specifically maximization of the total throughput of the Crusher by adjusting the eccentric speed (ω). The on-line optimization was based on the Extremum-Seeking Control (ESC) approach, which is advantageous when optimizing systems with unknown time varying characteristics. Two types of gradient based approaches are tested in simulation, the traditional Band-pass filters method and a method utilizing the Extended Kalman Filter (EKF). Both methods perform satisfactory, demonstrating the good potential of ESC for online-optimization of cone Crushers. To deal with unwanted behavior of the EKF based approach for situations when the gradient is not correctly estimated, a modification is suggested based on detecting this condition and accommodating for it.
Mohammad Ataei - One of the best experts on this subject based on the ideXlab platform.
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application of analytical hierarchy process to selection of primary Crusher
International journal of mining science and technology, 2014Co-Authors: Mohammad Javad Rahimdel, Mohammad AtaeiAbstract:Abstract Selection of Crusher required a great deal of design based on the mining plan and operation input. Selection of the best primary Crusher from all of available primary Crushers is a Multi-Criterion Decision Making (MCDM) problem. In this paper, the Analytical Hierarchy Process (AHP) method was used to selection of the best primary Crusher for Golegohar Iron Mine in Iran. For this reason, gyratory, double toggle jaw, single toggle jaw, high speed roll Crusher, low speed sizer, impactor, hammer mill and feeder breaker Crushers were considered as alternatives and capacity, feed size, product size, rock compressive strength, abrasion index and mobility of Crusher were considered as criteria. As a result of our study, the gyratory Crusher was offered as the best primary Crusher for the studied mine.
