Beschreibung
Not all plastics processing plants have the same facility layouts and designs. Some may engage automation systems while others may rely more on the labor forces. But as far as material flow systems are concerned, there is little difference among them. Figure 3.1 shows a typical material flow diagram of a plastics processing plant. As can be seen from Figure 3.1, after a solid bulk material such as resin is brought to the plant by trucks, it will be stored in storage tanks until it is needed for processing. Transportation of the bulk material from the storage tanks to the hoppers of the processing machines when needed is usually carried out in pipes by pneumatic conveying systems. If the bulk material is the only required raw material for making the products, it will be the only material fed into the hopper. But when additional raw materials (e.g., other types of resins and additives) are needed for processing, all the ingredients will then be either separately discharged into the hopper where they will be mixed and/or dehumidified, or they will be premixed before being discharged into the hopper. In some circumstances, such as in making masterbatches, dosing devices will be employed for monitoring the feeding into the hopper that sits on a processing machine. Finished products coming out from the processing machines need to be cooled and solidified before they are stored in warehouses to wait for shipping. If the products are semifinished products like compounded resins or masterbatch concentrates, drying and dewatering (if water baths are used for cooling) of the solidified strands are required before they are pelletized, packed, and stored. Echoing what was mentioned in Chapter 1 on the conceptual structural breakdown of the plastics processing technology suggested by Tadmor and Gogos [1], the above discussion on the basic flow of materials in the industry indicates that handling particulate solids is the first processing component of the elementary steps in plastics processing. Understanding of the fundamental characteristics of the particulate solids (i.e., particles) is an essential prerequisite for proper hardware designs and process controls. These fundamental material characteristics include mean particle size and size distribution, particle shape, and particle density, which will be discussed in the following sections of this chapter.
Industrial processes involving handling of solid raw materials are highly dependent on our understanding of the fundamental characteristics and properties of the starting solid materials, as well as whether or not the related process hardware and operation are properly designed and optimized. This is true of almost all plastics manufacturing processes since particulate solids handling is the most elementary processing step. This book provides a broad understanding of powder technology and the significance of particulate solid characteristics that are applicable to plastics manufacturing processes. It focuses on the particular characteristics of solid materials relevant to plastics manufacturing processes. Applications of engineering principles based on the selected solid characteristics which illustrate the uniqueness of the subject are also included. The useful and practical information within offers engineers solutions to otherwise unclear problems commonly encountered in industry. The selected examples of research investigations provided should also inspire readers to formulate further fundamental as well as applied research studies on the inter- and intra-relationship between powder technology and plastics processing technology. Contents: Introduction Polymers, Additives, and Processing Fundamental Parameters of Powder Characteristics SolidSolid Mixing Storage and Discharge of Particulate Solids Pneumatic Conveying of Particulate Solids Gas Fluidization Interparticle Forces Effects of Particle Characteristics on Rheological Properties of Polymeric Melts
Autorenporträt
Dr. Anthony (Chi Ying) Wong is Market Coordinator - Asia Pacific at Badger Color Concentrates. He has over 35 years of experience in both industry and academia in the area of plastics and manufacturing, including postions at BASF, Exxon Chemical, and the University of Hong Kong. He holds a Ph.D. from the University of Bradford, UK.
Herstellerkennzeichnung:
Carl Hanser Verlag GmbH & Co.KG
Vilshofener Straße 10
81679 München
DE
E-Mail: info@hanser.de
