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Trash Rakes
Published in Tom M. Pankratz, Screening Equipment Handbook, 2017
Standard duty trash rakes are furnished with a single hoist drum and one set of cables to lift objects up to 17″ (430 mm) in diameter, with hoist capacities to 2000 lb (900 kg). Heavy duty units may be capable of lifting objects up to 24″ (600 mm) in diameter and are furnished with dual hoist drums and two sets of cables, with hoist capacities to 4600 lb (2000 kg). The hoist mechanism should be equipped with a slack cable safety switch and an over-travel switch. Hoist drive motors typically range from 1 to 7.5 horsepower (0.75 to 5.6 kW).
Benefits realized and lessons learned from modeling the production capacity of the Jansen Potash Project
Published in Mineral Processing and Extractive Metallurgy Review, 2020
Using SLICE to model the ON/OFF nature of the mining system and the ON/OFF nature of the hoist system misrepresented two very important KPIs. The first KPI is the degree of blockage. An area is blocked (i.e. stops) if the inventory that it feeds is full. The mining, hoist, and mill areas can each experience blockage. The second KPI is the degree of starvation. An area is starved when the inventory it pulls from is empty. The hoist and mill areas can each experience starvation but the mine being at the front of the chain cannot. Because the mill is the bottleneck of the Jansen chain, mill starvation and mill blockage were the most important metrics. The DICE model aligned all stakeholders to the critical importance of minimizing mill starvation and mill blockage. Since the mill is the bottleneck, the hoist that precedes it must have a higher production capacity. The mining system that precedes the hoist must have a higher production capacity than the hoist. For example, too large hoisting capacity results in an ON/OFF operation of the hoist, causing high hoist blockage during OFF periods. Therefore, the capacity of the mining and hoist systems needs to be large enough but not excessively large as to cause high blockage. Too large capacity implies that a piece of equipment is over-sized, there is too many redundant pieces of equipment, and there is a waste of capital and higher-than-necessary opex (more labor, more maintenance).
Simulation platform for constant deceleration braking system based on Simulink
Published in Australian Journal of Mechanical Engineering, 2018
Li Juanjuan, Meng Guoying, Wang Aiming, Jia Yifan
As a key equipment in the mine production process, the mine hoist is the link between the ground and the underground, and undertakes the important tasks of lifting coal and ore and elevating personnel, materials and equipment. The braking system of the hoist is the last safeguard to ensure the safe operation of the hoist. Once the braking system fails, it may affect the safety of the hoist and even the whole mine, thus causing huge property losses and probably resulting in casualties and catastrophic accidents (Li, Hu, and Meng et al. 2017). Therefore, it is necessary to deeply study the performance and control parameters of the braking system. Because of the high cost of the braking system and the safety braking will affect the lifting equipment and affect the service life, simulation is a very effective research method (Yang, Xu, and Zhang et al. 2001). In this paper, the Simulink software was used to establish the simulation model of braking system, and the dynamic characteristics of the braking system are studied. The Simulink model provides support for the design and research of the safe and reliable braking system with excellent performance. The main parameters of simulation patform are shown in Table 1.
Mixed-integer linear programming method for multi-degree and multi-hoist cyclic scheduling with time windows
Published in Engineering Optimization, 2018
Yong-nian Mao, Qiu-hua Tang, Zi-xiang Li, Li-ping Zhang
This article considers an automated electroplating line which contains computer-controlled hoists and processing tanks. As shown in Figure 1, hoists are mounted on one track and indexed as hoist 1, hoist 2, … , hoist from left to right. The processing tanks are arranged in a row and indexed as tank 1, tank 2, … , tank sequentially from left to right. The loading tank and unloading tank are indexed as tank 0 and tank , respectively.