Craig Wheeler

Sliding-Mode Control of an Electromagnetic Actuated Conveyance System Using Contactless Sensing

A microcontroller-based conveyance system using a hybrid electromagnetic suspension (EMS) system and a linear synchronous motor (LSM) is proposed. Unique placements of the hybrid EMS and LSM integrated with an array of infrared sensors, embedded microcontroller, and electronics switching circuits are designed to maintain the air gaps and the propulsion. To improve the air-gap stability, a robust sliding-mode feedback controller is used. The entire control system is implemented, simulated, and verified by experimental measurements. As compared to different control schemes such as the H-infinity and the proportional-integral-derivative controller, it has shown to give reasonable performance under certain parametric uncertainties.

Design of ship loading chutes to reduce dust emissions

This article presents an industrial case study to reduce dust emissions from a grain handling ship loader. The primary objective of the study was to reduce dust emissions to within acceptable environmental levels during ship loading. Several constraints were imposed on the solution as the result of time and budgetary restrictions, and the inability to add a dust suppression agent to the grain for quality reasons. Although this article specifically deals with grain, application of this technology is also equally suitable for reducing dust emissions while handling other particulate commodities.

A New Approach for Calculating the Mass Flow Rate of Entrained Air in a Freefalling Material Stream

This article presents the outcomes from a series of physical experiments to measure the air entrainment rates encountered within a stream of freefalling particles. The experimental work presented spans a range of particle parameters and hopper geometries. From these results a new theory for the prediction of air entrainment is developed and presented. This new method was developed specifically to facilitate a better understanding in the area of fugitive dust control associated with material handling systems, which are driven by the air entrainment during freefalling. From the work presented in this article, a better prediction capability of freefalling bulk materials in either constrained, or unconstrained systems, will allow for the optimization of either passive or active dust control strategies. This article presents several distinct sections that detail the experimental work used to determine the freefall stream parameters that were conducted to allow the development of the entrainment equations.

Design, modeling and experimental testing of magnetic levitation system for conveyance applications

A novel magnetic levitation conveyor system consists of a linear synchronous motor and a hybrid electromagnetic levitation system was designed and built. The linear synchronous motor for propulsion was constructed using non-contact digital commutation while the hybrid electromagnetic levitation system was implemented using two permanent magnets and electromagnets for vertical levitation. The proportional-integral-derivative (PID) controller was coded using PIC18F4520 microcontroller to control the air gaps of a non-linear hybrid electromagnetic levitation system. The responses of both simulation and experiment show some agreement as the magnetic levitation and propulsion are both achievable in the proposed design.

Rotating Resistance of Belt Conveyor Idler Rolls

The primary function of idler rolls in a belt conveyor system is to support the conveyor belt along its length. Predicting the cumulative resistance of idler rolls is vitally important in calculating the belt tension and therefore power requirements of a system, particularly on long overland conveyors where there are typically more than one thousand idler rolls per kilometer of belt. The rotating resistance occurs due to the friction of the rolling elements in the bearings, the viscous drag of the lubricant, and the friction of the contact lip seals. This paper provides theoretical methods to calculate each component of the rotating resistance and describes an apparatus designed to measure this resistance force under simulated operating conditions.

Development of the rail conveyor technology

Abstract This article describes a new continuous conveying technology for the transportation of bulk materials. The new technology merges the benefits of both belt conveyor technology and railway to produce a highly energy-efficient and cost-effective bulk material transportation system known as the Rail Conveyor. An overview of the development of the Rail Conveyor system is presented, including scale model construction and evaluation, development and testing of a full-scale demonstration system, and a detailed economic comparison with belt conveyors. The Rail Conveyor provides an innovative and novel departure from conventional bulk material transportation systems with significant energy and economic benefits.

Modelling of an innovative rail conveyor system

Belt conveyors are regarded as the most common material handling systems in the modern world due to their ability to handle a vast range of bulk materials. Modern belt conveyors are used in a wide range of industries ranging from food manufacturing to power generation. Although belt conveyors have been around for centuries, their principle structure have been unchanged. In this paper a novel type of conveyor system is taken into account and a mathematical model that allows the analysis of the dynamic states of the proposed belt conveyor is presented. The novel conveyor system identified as the rail conveyor implements a cart based propagation technique abandoning the traditional idlers. The simulation model is conceived by adopting a finite number of elements consisting of springs, masses, and dampers for various forces existing in the belt and other structures of the rail conveyor. Each rheological model comprised of elements described later in this paper are formulated to characterize innate qualities such as viscoelastic behavior of the belt and resistance forces experienced by the carts in the rail conveyor system.

Investigation of belt conveyor transfer chute configurations to reduce dust generation using CFD modeling

“Passive” dust control systems for belt conveyor transfer stations have become increasingly popular in recent years. Effective design relies on a fundamental understanding of the flow of granular material and air throughout the transfer chute. This paper presents an investigation into the flow properties of the air and particles in the enclosure for different transfer chutes based on computational fluid dynamics (CFD) modelling. A multiphase Euler-Euler model was applied to develop a 3D model of the transfer chute. Experiments were undertaken to verify the theoretical models, with overall results indicating good correlation. Furthermore, a number of alternative transfer chute configurations were modelled to investigate the effect of geometry on dust generation.

The Mechanics of Feeding Bulk Solids in a Rotary Dryer

Based on an industrial case study, the performance of a rotary dryer employed in a mineral processing plant was investigated. The loads on the rotating elements of the dryer are analyzed with a view to ascertaining possible causes of failure. The particular type of dryer comprises a steam-heated drying unit composed of a central hollow drum and a number of parallel sets of circular heating tubes attached to the drum via radial header tubes. The drying unit rotates inside a stationary vessel containing the moist mineral ore. Blades attached by welds to the outer circular heating tubes assist in the circulation and transport of the ore through the dryer. However, in the actual dryer, the blade angles were less than optimal for good feed of material through the drying unit, and their welded attachments were a source of high levels of concentrated stress. While the close spacing between parallel sets of circular heating tubes is beneficial for heat transfer for the drying process, the close spacing leads to material buildup problems impeding the material feed. Influence of the variation of blade angle on feeding performance was investigated, and the various loads acting on the tubes and blades were analyzed.