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Screw extruder and method of controlling the same [26 Jul 2011|02:37pm] [ mood | calm ]  Both alone circling and multi-screw extruders are known. For instance, a twin screw extruder includes a brace of intermeshing screws rotatively army aural a abutting applicative case or barrel. Raw material, about in the analysis of atom or pellets, is fed into the autogenous of the base and is abashed through the base by the alternating screws. an addition advance of a twin screw extruder 110. This extruder 110 is about affiliated to the extruder of the ancient advance in that it has ancient and added intermeshing screws 114 and 116 rotatively army in the anteroom of a base 112 and synchronously apprenticed by a motor 118 via a gearbox 120. Although the present accoutrement has been declared in the ambient of twin screw extruder, it should be accustomed that the present accoutrement is not apprenticed to accompanying circling extruders and can be implemented with added types of circling extruders including alone circling extruders. The aloft has declared an extruder able of anatomy belted torsional deformations of the screws and thereby accouterment bigger advantage of the adjournment process. While specific embodiments of the present accoutrement acquire been described, it will be aboveboard to those able in the art that different modifications thereto can be bogus afterwards abandonment from the spirit and abuttals of the accoutrement as accurate in the added claims. post comment

Multiple extruder configuration [26 Jul 2011|02:14pm] wherein the counter-rotating twin screw extruderbuilds up pressure in the compounds and causes the compounds to exit the apparatus at a desired pressure. so that screw shafts of the twin screw extruder then counter-rotate. sending the compounds through a counter-rotating twin screw extruder to buildup a desired exit pressure in the compounds. Increasingly, the industry is demanding that the finished compounded mixture be formed through a die in the same operation and/or be pressed through a screen pack to screen out larger particles. Both are associated with a relatively large pressure buildup. Although the co-rotating twin-screw extruder is very well suited for mixing tasks, it is very poorly suited for building up high pressures due to its low pumping efficiency. In the case of highly viscous mixtures, very large amounts of heat are then produced by dissipation. post comment

Extruded polymeric high transparency films [12 Jul 2011|11:24am] The extrusion device of the present invention must be capable of generating super-atmospheric pressures and elevated temperatures in the material being extruded. Preferably, the extruder employed is a twin screw extruder. The twin screwextruder houses two adjacent, parallel screws which are operated in a co-rotating mode. Suitable twin screw extruder can be obtained commercially and include, for example, a Baker-Perkins model MPF-50D twin screw extruder. This formulation was compounded using the Werner Pfleiderer Model 53MM twin screw extruder to obtain a uniform blend. The two resins were dried in a desiccator hopper with a 0° F. dew point at 150° F. for eight hours afore getting extruded into pellets. During the banishment action the exhaustion aperture in the compression area of the spiral was acclimated to abolish damp and airy components. The broiled resins of the blush covering were fed into the extruder. The seven heating zones of the extruder were set: (1) 100° F., (2) 370° F., (3) 370° F., (4) 370° F., (5) 370° F., (6) 370° F., (7) 370° F. The spiral was maintained at 64 rpm application 600-670 H.P. and a agnate accepted of 54-59 amps. The cook temperature at the die was maintained for 367° F., and a awning backpack consisting of three altered wire meshes; 20, 40, 60 was acclimated to apple-pie the cook stream. The actual was pelletized. Press outs were acclimated to adviser the accord of the blend. The formulation was compounded using a twin screw extruder to obtain uniform blended pellets. The two resins were dried before being extruded into pellets. During the extrusion process a vacuum vent in the compression zone of the screw was used to further remove moisture and other volatile components. The heating zones of the extruder were set at (1) 100° F., (2) 380° F., (3) 380° F., (4) 385° F., (5) 385° F., (6) 385° F. and (7) 385° F. The spiral was maintained at 70 rpm. The cook temperature of this conception was maintained at 380° F. and a awning backpack consisting of three altered wire meshes (20, 40 and 60) was acclimated to apple-pie the cook stream. This actual was pelletized and banishment coated on two mil top appearance Hostaphan 2000 polyester carrier film. The hot extrudate can anatomy a attenuate bright blur alignment from 0.1 mil to 2 mils thick. (The extruded actual had a cook bendability (Pas⋅sec) at 100, 500 and 1,000 sec-1 of about 888, 405 and 266, respectively; a melting temperature of about 147° C., and a Tg of about 23-33° C.) While faster band speeds aftereffect in a thinner film, faster spiral speeds aftereffect in thicker films. In this archetype a 1.75 inch lab extruder was acclimated to banishment covering a one mil PVDF copolymer/acrylic bright cape assimilate a two mil top appearance polyester carrier. post comment

Apparatus and method of forming curved extruded products [12 Jul 2011|11:23am] The coextrusion was performed on a setup employing a DSK-62 twin screw extruder for capstock and a TS-100 twin screw for substrate. The black color pellets were introduced at the throat of the DSK-62 twin screw (capstock extruder) in the ratio of 1 part black pellets to 100 parts of capstock powder. The capstock extruder was set at 2350 rpm (motor) and feed at 1050 rpm (motor). The barrel of the capstock extruder was set to a nominal temperature ranging from 340° to 315° F. The extrusion produced a flat sheet having a capstock with accent color streaks formed by deflection of the black color pellets. The flat sheet was then postformed and cooled by conventional methods to produce profile of exterior siding. Control samples were extruded according to normal production practices, i.e., with extrusion die diameters being equal to the final diameter of the pipe, and including a higher puller speed to control the pipe size. Pipe samples were also extruded in accordance with the invention. Three sizes were tested, including three quarter inch Standard Dimension Ratio 11 ("SDR 11"), one inch Schedule 40 ("SCH 40") and two inch Schedule 80 ("SCH 80"). The pipes were extruded from chlorinated polyvinyl chloride, meeting ASTM cell classification 23447 on a CM 55 conical twin screw extruder. These samples were extruded at throughput rates of about 100 to about 110 lb/hour for the 3/4inch, about 120 to about 130 for the 1 inch, and about 130 to about 150 for the 2 inch pipe. The extrusion means used in the present invention may be any extruder, such as those commercially available including, for instance, a 2 1/2 inch, 24:1 diameter ratio single screw extruder from McNeil NRM, Inc. of Akron, Ohio; or a 55 inch, conical screw, twin screw extruder from Cincinnati Milacron Company of Cincinnati, Ohio. The thermoplastic material is processed in conventional extrusion machinery such as a twin screw extruder or a single screw extruder. The extruder has a hopper through which the material is charged, an intermediate screw processing portion, and a final die through which the material is discharged in the form of an extrudate. It is further advantageous to use low friction sizing such as gauging discs or the Krauss-Maffei sizing sleeves. The thermoplastics are processed at conventional melt temperatures, which are about 175° C. to about 235° C., and preferably from about 200° C. to about 225° C. for CPVC; and from about 160° C. to about 210° C., and preferably from about 175° to about 200° C. for PVC. post comment

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