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Browsing Chemical Engineering by Author "Abdel-Jaleel, Yomna"
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- ItemModification of Polypropylene Random Copolymer(PPRC) pipe by poly olefin polymers.(2014) Odeh, Areej; Abdel-Jaleel, Yomna; Alzhra Hafiz, Fatima; Rasheed, RasheedPlastic extruders are used to create a wide range of items, including plastic tubing, trims, seals, plastic sheets and rods. Extruder is the machine for producing more or less continuous lengths of plastic sections out of a selected type of plastic resin. There are a number of extrusion techniques available such as co-extrusion, offset extrusion, oriented extrusion, overcoat extrusion, cold extrusion, ram extrusion and much more. The essential elements for a thermoplastic extruder are a tubular barrel, usually electrically heated; a revolving screw, ram or plunger within the barrel; a hopper at one end from which the material to be extruded is fed to the screw, ram or plunger; a die at the opposite end for shaping the extruded mass. Extruders may be divided into three general types: * Single Screw Extruder. * Twin or Multiple Screw Extruders. By far the most common and most versatile extruder in use today is the single-screw extruder. Single-screw extruders are characterized by two dimensions; the bore diameter (D), and the length of the barrel in bore diameters or L/D ratio. The function of single screw extruder The extruder function is to mix and plasticize the granule or powder plastic into melting, extrude the melted material out barrel under the suitable pressure. The structure characteristic of single screw extruder The extruding system of single screw extruder is composite of one screw and one barrel, electric heater, and forming mould. Single screw extruder is applicator widely. By changing the screw structure type, it can extrude and mold different raw material plastic products. Single screw extruder has a characteristic of low cost, simple operation, easy maintenance and convenience checking and repairing. Single screw extruder • Screw diameter means the outer diameter of screw parts, usually use D to represent. • Screw L/D, it is the value that screw length/screw diameter. • Screw rotating speed range: it means the min. speed and the max. Speed when working. • Motor power: mean the driving motor power which drives screw to rotate the unit is Kw. • Barrel heating power: it is the electric consumption power when heating the barrel. • Heating zone: it is the temperature controlling zone numbers. • Extruder capacity: it is the plasticization capacity in unit time. Twin screw extrusion is used extensively for mixing, compounding, or reacting polymeric materials. The flexibility of twin screw extrusion equipment allows this operation to be designed specifically for the formulation being processed. For example, the two screws may be co-rotating or counter rotating, intermeshing or no intermeshing. In addition, the configurations of the screws themselves may be varied using forward conveying elements, reverse conveying elements, kneading blocks, and other designs in order to achieve particular mixing characteristics. Although twin screw extruders can be used with any thermoplastic, their added complexity is normally acceptable only when required for special characteristics such as lower sheet heat. Common multi-screw applications include e.g. large diameter rigid PVC pipe, compounding of certain polymers, and processing of heat-sensitive materials or materials that must leave the die at relatively low temperatures. PPRC pipe production/extrusion line/PPRC pipe making machinery is used to produce PPR pipes for cold and hot water supply. It's composed of vacuum feeding machine, hopper dryer, single screw extruder, mould, make line co-extruder, vacuum calibration and cooling tank, extended spraying cooling tank, haul off machine, cutter and stacker. PPRC cool and hot water pipe extrusion line is used by single screw extruder for extruding the pipes with various tube diameters and the wall thickness.