Polyethylene leads all plastics in the volume of resin used each year. They are produced in three types : low, intermediate and high density. All three types have in common the properties of toughness , resistivity to solvents, alkalies, excellent dielectric properties, good colorability , very low moisture absorption and relatively low cost . The polyethylenes are blow and injection - moulded , extruded into very wide range of products which includes house wares such as bowls , plates, dishpans, paint-brush handles, flexible tubing, bags for packaging vegetables , hardware , squeeze bottles etc.,
Various types of melting furnaces are used in different foundry shops, depending upon the quantity of metal to be melted at a time, and the nature of work that is carried out in the shop. The primary objective in cupola is to produce iron of desired composition, temperature and properties at the required rate in the most economical manner. Besides, this furnace has many distinct advantages over the other types, e.g., simplicity of operation, continuity of production, and increased output coupled with a high degree of efficiency. Description Of a Cupola : The Cupola Furnace consists of a vertical, cylindrical steel sheet, 6 to 12 mm thick, and lined inside with acid refractory bricks or acid tamping clay. The refractory bricks or the tamping clay used consist of silicon oxide acid (SiO2) and alumina (Al2O3). The lining is generally thicker in the lower where the temperatures encountered are higher than in the upper region. The shell is mounted either on a brick work fo...
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