Belt conveyors play an important role in the dry bulk material handling process. Speed control is a promising method of reducing the power consumption of belt conveyors. However, inappropriate transient operations might cause risks like material spillage away from the belt conveyor. The unexpected risks limit the applicability of speed control. Current studies on speed control mainly focus on designing energy models of belt conveyors or building control algorithms of variable speed drives, while rare researchers take into account the risks in transient operations and the dynamic performance of belt conveyors under speed control. The paper proposes an Estimation-Calculation-Optimization (ECO) method to determine the minimum speed adjustment time to ensure healthy transient operations. The ECO method is composed of three steps and takes both risks in transient operations and the conveyor dynamics into account. In the Estimation step, an estimator is built to approximate the permitted maximum acceleration by treating the belt as a rigid body. Taking the belt's visco-elastic property into account, the Calculation step computes the conveyor dynamics by using a finite-element-method. With respect to the risks in transient operations, the Optimization step improves the conveyor's dynamic behaviors and optimizes the speed adjustment time. A case of a long belt conveyor system is studied and the ECO method is applied. The secant method is also used to improve the optimization efficiency. According to the experimental results, the ECO method is successfully used to determine the minimum speed adjustment time to ensure healthy transient operations, including both the accelerating and the decelerating operations. With the suggested adjustment time, unexpected risks are avoided and the belt conveyor shows an appropriate dynamic behavior. Accordingly, the ECO method ensures healthy transient operations and improves the applicability of speed control with the consideration of the potential risks and the conveyor dynamics.@en

Belt conveyors can be partially loaded due to the variation of bulk material flow loaded onto the conveyor. Speed control attempts to reduce the belt conveyor energy consumption and to enable the green operations of belt conveyors. Current research of speed control rarely takes the conveyor dynamics into account so that speed control lacks applicability. Based on our previous research, this paper will provide an improved three-step method to determine the minimum speed adjustment time. This method can be summarized as Estimation-Calculation-Optimization and ECO in short. The ECO method takes both the potential risks and the conveyor dynamics into account. It is expected to keep belt conveyors in good dynamic behaviors in transient operations. After discussing the ECO method, this research takes a long inclined belt conveyor of an import dry bulk terminal as case study. Based on the suggested acceleration time, a speed controller is built and computational simulations are carried out to evaluate the energy savings and the conveyor dynamics. Experimental results prove that the application of the ECO method ensures the healthy dynamic performance of belt conveyors under speed control in transient operations. Annually, the average electricity consumption of the single conveyor can be reduced by over 10% with around 90 tons reduction of emission. The direct economic benefit can reach up to more than €10,000 in terms of the electricity utilization per year.@en

Belt conveyors are widely used in bulk solids handling and conveying systems. Considering the extensive use of belt conveyors, their operations involve a large amount of energy. Taking the relevant economic and social challenges into account, there is a strong demand for lowering the energy consumption of belt conveyors, and for reducing the carbon footprint. Speed control is one of the promising approaches for reducing the power consumption of belt conveyors. This thesis focuses on the application of speed control to belt conveyors for reducing their energy consumption. Research on belt conveyor speed control has already been carried out for more than twenty years. However, rare implementations of speed control to reduce energy consumption can be found in practice. One major reason is that the current research does not cover issues like the potential risks (such as the risk of belt over-tension, the risk of belt slippage around the drive pulley and the risk of motor over-heating) and the dynamic analyses of belt conveyors in transient operations. Therefore, speed control of belt conveyors is not often successfully applied in practice...@en

Speed control has been found a feasible mean to reduce the energy consumption of belt conveyors. However, the current research has not taken the determination of the acceleration in transient operation into account sufficiently. With respect to the belt tension rating, demanded safety factor and the ratio between belt tension before and after drive pulley, this paper presents an approach to estimate the acceleration time. Case with specific horizontal belt conveyor is studied. The simulations with finite element model are carried out to analyze the belt dynamic behaviors in transient operation. Further simulations are carried out to get the optimum acceleration time.@en

Belt conveyors play an important role in continuous dry bulk material transport, especially at the mining industry. Speed control is expected to reduce the energy consumption of belt conveyors. Transient operation is the operation of increasing or decreasing conveyor speed for speed control. According to literature review, current research rarely takes the conveyor dynamics in transient operation into account. However, in belt conveyor speed control, the conveyor dynamic behaviors are significantly important since the poor dynamics might result in risks. In this paper, the potential risks in transient operation will be analyzed. An existing finite element model will be applied to build a conveyor model, and simulations will be carried out to analyze the conveyor dynamics. In order to realize the soft speed regulation, Harrison’s sinusoid acceleration profile will be applied, and Lodewijks estimator will be built to approximate the required acceleration time. A long inclined belt conveyor will be studied with two major simulations. The conveyor dynamics will be given.@en

Belt conveyor systems are widely utilized for continuous transport of bulk materials. Maintenance activities are essential to ensure the reliability of belt conveyor systems. Conventional diagnosis decision is achieved based on empirical constant thresholds. The Challenge of this study is to propose a framework of integrated maintenance decision making for belt conveyor idlers. Information from operational conditions, reliability estimation of idlers and condition monitoring data are integrated for accurate decision making. Innovatively, in the proposed framework threshold of the monitoring parameter can vary according to real time operational conditions and reliability estimation results. A simulation study is presented to demonstrate the effectiveness of framework. Simulation results show that the framework can result in more accurate maintenance decision making compared to conventional approaches.@en

Belt conveyor systems are widely utilized for continuous transport of bulk materials. Maintenance activities are essential to ensure the reliability of belt conveyor systems. Conventional diagnosis decision is achieved based on empirical constant thresholds. The Challenge of this study is to propose a framework of integrated maintenance decision making for belt conveyor idlers. Information from operational conditions, reliability estimation of idlers and condition monitoring data are integrated for accurate decision making. Innovatively, in the proposed framework threshold of the monitoring parameter can vary according to real time operational conditions and reliability estimation results. A simulation study is presented to demonstrate the effectiveness of framework. Simulation results show that the framework can result in more accurate maintenance decision making compared to conventional approaches.@en

Belt conveyor systems are widely used in bulk material handling and transport applications. Within a belt conveyor, depending on its distance, there can be tens of thousands of idler rolls which face random failure. However, condition monitoring solutions for belt conveyor idlers is underdeveloped. This is because the choice of monitoring parameters is still arbitrary. This paper aims to investigate which parameters can represent technical condition of idler rolls for the purpose of condition monitoring. A belt conveyor test rig is developed in laboratory. Temperature and vibration sensors are applied to monitor idler rolls induced with different types of failures. Patten of temperature evolution and RMS level of vibration are extracted from the signal and analysed. It is concluded that temperature measurement at roll shafts is a straightforward and effective manner for condition monitoring of belt conveyor idlers.@en

Belt conveyor systems are widely used in bulk material handling and transport applications. Within a belt conveyor, depending on its distance, there can be tens of thousands of idler rolls which face random failure. However, condition monitoring solutions for belt conveyor idlers is underdeveloped. This is because the choice of monitoring parameters is still arbitrary. This paper aims to investigate which parameters can represent technical condition of idler rolls for the purpose of condition monitoring. A belt conveyor test rig is developed in laboratory. Temperature and vibration sensors are applied to monitor idler rolls induced with different types of failures. Patten of temperature evolution and RMS level of vibration are extracted from the signal and analysed. It is concluded that temperature measurement at roll shafts is a straightforward and effective manner for condition monitoring of belt conveyor idlers.@en

In bulk material handling applications, belt conveyors generally run at a constant speed. The belt can be only partially filled when the loaded material flow at the tail of the conveyor is smaller than the nominal conveying capacity of the system. Literature including DIN 22101 indicates that reducing the belt speed, and thereby maximizing the belt loading degree, always results in a reduction of the required drive power. To maximize the loading degree in operations, belt conveyor speed control has been proven to effectively achieve energy savings in dry bulk material transport. Current studies of speed control mainly focus on establishing models to predict the energy savings and on developing methods for variable conveyor speeds in conveyor startup operations. There is little research that focuses on the effect of belt conveyor acceleration in transient operations associating belt conveyor dynamics. If the acceleration is too high and the regulation of speed is too frequent, speed control may potentially damage the system or reduce the technical lifetime of the entire system. This paper presents an approach to determine the admissible acceleration and the applicable acceleration frequency under transient operations. Taking into account the risks of belt over-tension, slippage between drive pulley and belt and drive motor overheating, the maximally allowed acceleration is estimated. Further the estimation is evaluated by finite element method to optimize the acceleration towards a proper speed control process with respect to conveyor dynamics. A case study shows the implementation of the approach.@en

Belt conveyors play an important role in continuous dry bulk material transport. Large scale belt conveyor systems consume a considerable amount of electricity. The approach of controlling the belt speed in such a way that the belt's volumetric capacity is fully utilized under all operational conditions has been proven to significantly reduce the energy consumption of a belt conveyor. Current research on speed control for belt conveyors mainly focuses on the calculation and the prediction of possible energy savings. Few studies focus on the dynamics of belt conveyors in transient operation. There are however no studies that describe the operation of speed controlled belt conveyors during transient operation. This paper presents a three-step method that can be used to determine a proper way to accelerate a speed controlled belt conveyor during transient operation. This method takes the potential risks in transient operation and the conveyor dynamic performance into account. A case of horizontal conveyor system is studied and the three-step method is applied. In the case study, a predictor of the permitted maximum acceleration is calculated. Simulations with the predicted acceleration time are carried out to determine the acceleration operation and to analyse the conveyor dynamics. The simulations are based on an existing finite element model of a belt conveyor.@en