Pipes extrusion

UT for Plastic Pipe extrusion. State of the art, 20 chapters inch 30 Fig.,... 

Fig. 4.19(b) Pipe extrusion (1) rigid pipe (2) flexible pipe... 

PIPE EXTRUSION IMPROVED PIPE EXTRUSION HOKES STANDARD EXTRUSION... 

Polyethylene is readily fabricated by all methods of thermoplastic processing. The principal methods used are film and sheet extrusion, extrusion coating, injection molding, blow molding, pipe extrusion, wire and cable extrusion coating, rotomolding, and hot melt and powder coatings. 

Annular flow is encountered in pipe extrusion dies, wire coating dies and film blowing dies. In the problem under consideration, a Power law fluid is flowing through an annular gap between two coaxial cylinders of radii kR and R, with k < 1 as schematically depicted in Fig. 5.15. The maximum in the velocity profile is located at r = j3R, where / is a constant to be determined. Due to the geometrical characteristics and ignoring entrance effects, the flow is unidirectional, i.e., u = (ur,ue,uz) = (0,0, wz(r)). 

As the plastic exits the die it is cooled on a conveyer. In addition to round pipe, extrusion lends itself to other shapes that are long and continuous, such as window moldings. Top companies in plastic pipe manufacture include Royal Group, Inc., J-M Manufacturing (doing business as JM Eagle) and CertainTeed. 

Polyethylene is the least costly of the major synthetic polymers. It has excellent chemical resistance and can be processed in a variety of ways (blown film, pipe extrusion, blow molding, injection molding, etc.) into myriad shapes and devices. Fabrication methods will be briefly discussed in Chapter 8. 

Petrothene [Quantum]. TM for polypropylene resins for blown, cast, and water-quenched films, substrate coating, wire and cable coating, injection molding, blow molding, thermoforming, pipe extrusion, calendering. 

Finatbene . [FinaChem.] High-density polyethylene homq >olymers and copolymers for blow molding, film blowing, pipe extrusion, cable jacketing. 

Nipolon. [Tosoh] Polyethylene resins used for blow molding, blown film, extrusion pipe, extrusion coadng and laminating, inj. molding, filament... 

A range of products can be obtained using the Lupotech T process, including standard LDPE grades to EVA copolymers or n-butyl-acrylate modified copolymer. The products can be applied in (shrink) film extrusion, injection molding, extrusion blow molding, pipe extrusion, pipe coating, tapes and monofilaments. 

Extruded products, such as pipe, sheet or complex profiles for window frames, have a constant cross section. Figure 5.8 shows part of a pipe extrusion line the continuous output must either be coiled, if it is sufficiently flexible, or cut into lengths and stacked for distribution. All parts of the line must be carefully controlled to keep the product dimensions within the acceptable limits. We will concentrate on the analysis of the extruder output. 

Among these heat stabilisers, those containing tin (such as tin mercaptides, and tin carboxylates or maleates) are considered to be the most efficient, and can be used in a wide variety of applications. Metallic tin is harmless but there are suspicions that organotin-compounds can be toxic to the central nervous system and the liver. However, tin stabilisers have a low capacity for migrating, and hence they are still considered to be safe. Tin stabilisers such as methyl and octyl tins are used in food contact applications. For PVC, it is believed that tin stabilisers act as HCl scavengers (generating tin chloride) as well as an antioxidant. Thio-tin compounds (preferred for rigid pipe extrusions and profiles (for window frames) of PVC) may develop an odd odour due to sulfur. 

Schlickeysen builds the suspended sewer pipe extrusion machine including socket shaping with lowering table, which he patented Sachsenberg of Rosslau builds an upright expression rolls machine for the sewer pipe industry, which is successfully tested in Bitterfeld at the factory of Messrs. Polko Schlickeysen introduces a second feed roller for the extrusion machine... 

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