Feeders and their Types...

Feeders and their Types  Feeders are devices mounted at the outlet of storage units such as bins, bunkers, silos or hoppers which are used to control and meter the flow of bulk materials from the storage unit to meet the specified discharge flow rate. When the feeder stops, material flow ceases and when the feeder is turned on, there is a close correlation between its speed of operation and the rate of discharge of the bulk material. The importance of the feeder to be designed as an integral unit with the storage unit cannot be too greatly emphasized. A well designed storage unit may be prevented from functioning correctly if the feeder is poorly designed, and vice versa. It is particularly important that both the feeder and the storage unit are designed as an integral unit so as to ensure that the flow from the storage unit is fully developed with uniform draw of bulk material from the entire outlet of the storage unit. While there are several types of feeders which are used commonly, it is essential that they are to be selected to suit the particular bulk material and the range of feed rates required. The properly designed bulk material handling system always commences from the feeder, i.e. first equipment in the handling system (or section of the system), is always the feeder. The feeder decides the magnitude of load on the handling system. Therefore, the handling system load condition and thereby its performance is governed/controlled by the feeder. Feeders for controlling the flow of bulk materials onto conveyor belts require the following criteria to be met. They are to deliver the range of flow rates required. They are to handle the range of particle or lump sizes and flow properties expected....

Management of Internal Transport in Steel Plant...

Management of Internal Transport in Steel Plant Steel plant handles a huge amount of materials during the production of steel products. This huge amount of the materials is to be moved during the several stages of production. Various types of movements of men and materials which are taking place in a steel plant are described below. The materials movement starts with the receipt of raw materials and fuels which are to be stored and sent to the processing units for their processing. The intermediate products as well as semi-finished products need to be moved for the next stage of processing in the downstream units. The finished products and byproducts are to be dispatched to various customers. Waste products which are produced during processing are to be moved to the waste product processing units or to the dumps. Also steel plant requires store and spares, equipments, consumables, lubricants, utility items etc. in huge amounts which are to be received, stored and moved to the processing units. Steel plant also needs a large amount of water which is required for cooling, processing and many other purposes. This water is also to be received and transported to the places of need. Further a large number of people work in the plant who come to work in various types of vehicles. This vehicular traffic also consists of a big movement in the plant. The total cost of transportation of men and materials inside the plant is quite substantial and hence need a comprehensive and integrated management to keep it under control. Steel plant uses several means of transports for these movements. These movements include rail transport, road transport, conveyor transport, and pipe line transport etc. for inter shop movements while cranes, mono rails with trolleys, fork lifts, roller...

Selection of Coal for inclusion in Coal Blend in Coke Making Sep26

Selection of Coal for inclusion in Coal Blend in Coke Making...

Selection of Coal for inclusion in Coal Blend in Coke Making Blending of coals is necessary from economical point of view by reducing the percentage of high cost, prime or hard coking coals and replacing it with medium or soft coking coals. In some coke oven plants even a small percentage of non-coking or steam coals have also been used in the blend. Selection of a proper coal blend for use in by product coke ovens is always a big challenge for the coke producer since the blend has to meet the following requirements. It is to meet the requirement of crushing during coal preparation. All the components of the coals are neither be over crushed or under crushed. The sized coal blend for charging the coke ovens is to meet the requirements of density, flow, and the size fractions. It is to have necessary coking and caking properties for producing coke of quality which meets the quality requirements of blast furnace (BF) coke. The three basic quality requirements of BF coke are (i) to provide heat for the endothermic reactions taking place in the blast furnace, (ii) to act as a reducing agent by producing the necessary reduction gases, and (iii) to provide a permeable support in the BF for the iron bearing burden. It is to provide safe pushing performance in coke ovens. It must not put excessive pressure on coke oven walls during the process of coking and damage them. It should meet the yield requirements not only of BF coke but also of coke oven gas. A proper coal blend will not produce excessive nut coke and coke breeze. It is to be economical. In view of the above varied types of requirements, the decisions regarding coal blends are not...

Pumps and their Types...

Pumps and their Types Pumps of different types and sizes are used in large numbers in a steel plant. They have got a very wide range of application in the steel plant and in many areas, pumps form critical piece of equipment for the process. A pump is a device that adds energy into the fluids (liquid or gases), or sometimes slurries. The energy can be expressed in two ways i.e. either an increase in pressure or an increase in flow. Pumps are used to move or raise fluids. They are not only very useful, but are excellent examples of hydrostatics. Pumps operate by some mechanism, and consume energy to perform mechanical work by moving the fluid. Pumps operate via many energy sources, including manual operation, electricity, engines, or wind power. They come in many sizes, from microscopic to very large industrial pumps. Pumps may be classified as positive displacement pumps and non-positive displacement pumps (Fig 1). Fig 1 Types of pumps Positive displacement pumps These pumps deliver a constant volume of fluid in a cycle. The discharge quantity per revolution is fixed in these pumps and they produce fluid flow proportional to their displacement and rotor speed. These pumps are used in most of the industrial fluid power applications. The output fluid flow is constant and is independent of the system pressure (load). The important advantage associated with these pumps is that the high-pressure and low-pressure areas (means input and output region) are separated and hence the fluid cannot leak back due to higher pressure at the outlets. These features make the positive displacement pump most suited and universally accepted for hydraulic systems. The important advantages of positive displacement pumps include capability to generate high pressures, high volumetric efficiency, high power to weight ratio, change in efficiency...

Trade Unions and their Role in a Steel Plant...

Trade Unions and their Role in a Steel Plant Trade unions are independent, membership-based establishments of the employees that represent and negotiate on their behalf. They function in the organization with their presence registered with the management. They give advice when their members have problems at work, represent members in discussions with the management, and help improve wages and working conditions through negotiations.  Trade unions also make sure that the statutory requirements are met. Other functions carried out by trade unions are to arrange education and learning opportunities for the employees, promote equal opportunities at work, fight against discrimination and help to ensure a healthy and safe working environment. Many unions also provide services for their members, such as welfare benefits, personal legal help and financial services. Trade unions function on the principle that if all the employees speak with the same voice, their concerns are more likely to be addressed. This involves union members in the same workplace getting together to talk about common problems, democratically taking collective decisions on workplace issues, and putting these views to the management. It can be very difficult for employees to speak individually to the management about workplace problems and to resolve their difficulty individually even assuming that they have the confidence to raise the issue. Individual members usually elect someone to speak on their behalf (a shop representative) and to discuss their concerns with management, whereas the trade unions normally have regular formal discussions. These negotiations are referred to as ‘collective bargaining’. Trade unions are financed through the individual contributions of their members. They continually seek to recruit members (encouraging new members to join by ‘organizing’) and to build an active membership, as this give unions stronger bargaining power in negotiations with the management. Trade unions...