Abstract: A continuous mixer comprising at least one mixing zone formed by a Transfermix geometry in which the number of starts of the helical thread changes for each of the components along the length of said Transfermix zone in the opposite sense to the change of the cross-sectional area of helical grooves on said component, whereby when in operation a medium moves along said Transfermix zone, portions thereof are successively transferred between the grooves of facing helical threads as giver and taker and whereby grooves of larger cross-sectional area are of greater widths than grooves of small cross-sectional area; in a preferred embodiment the mixer has a driven rotor and stationary barrel, the helical threads thereon being of opposite hand and the number of starts facing one another at any cross-section of the Transfermix zone is such as to make a substantially constant product.

Abstract: Plastic articles are made wherein an additive is introduced downstream of an injector.

Abstract: A new extruder screw design incorporating an optimal flight helix angle and flight height in the feed section and metering section and a constantly varying helix angle with a constantly decreasing flight height in the transition section is disclosed; the screw being efficiently fed by use of a grooved section of extruder barrel in the area of the feed section.

Abstract: The extruder screw has a solid feed section followed by a solid-melt transition section, followed by a melt metering section. A solid feed channel extends from the feed end of the extruder screw up to a point within the solid-melt transition section. A solid-melt channel extends longitudinally from the beginning to the end of the solid-melt transition section. A melt channel begins within the solid-melt transition section just after the end of the solid feed channel and extends longitudinally to the end of the melt metering section.

Abstract: A single screw injection device or extruder sequentially injects skin and foamed plastics melts into a mold to produce structural skin covered foam molded parts free from swirl marks. A single extrusion screw or plasticator selectively feeds, compresses and meters a plastics melt to a first injector for skin melt injection or to a gas injection well where it meters gas flow into the melt, mixes the gas and melt to form a foam and feeds the foam to a second injector for foam melt injection into the mold. A valve controls the flow of the plastics melt and the foamed plastics melt to a single injection nozzle for discharge into the mold. In sandwich molding, a small amount of the unfoamed melt is first injected to form the skin for the molded article and then the valve is shifted to connect the nozzle with the foamed melt from the screw whereupon the injector forces the foamed melt through the nozzle into the mold to overlie the skin melt.

Abstract: Apparatus for devolatilizing materials such as solvent containing polymers includes a cylindrical housing having inlet and discharge ends and a screw member rotatably mounted in the housing, operative to work material so as to release contained vaporizable substances from the material. An inlet fitting at the inlet end of the chamber is located opposite a part of the screw member. The housing includes a venting section extending therefrom at the inlet end and the screw member has a screw vent control section extending within the venting section, arranged to convey material toward the discharge end of the housing.

Abstract: An improved screw feeder such as may be used for conveying ligno-cellulosic materials such as wood chips, shavings, sawdust and the like to pulping apparatus includes a plurality of stopper bars positioned symmetrically about the inner periphery of the screw feeder throat inlet. The stopper bars are narrow, elongate wedge-shaped and extend from the greater diameter flare bore of the conical throat to the lesser diameter taper bore. The stopper bars prevent material from rotating with the screw rather than advancing longitudinally through the throat and thus decrease plugging and clogging problems so that a higher pulping capacity due to improved feed is obtained.

Abstract: There is provided a screw for use in an extruder comprising a melting section and a metering section and a decompression section therebetween so that the head pressure profile along the longitudinal direction of the extruder is higher than atmospheric pressure and has an inflection point, with the result that a high melting performance is attained and a high extrusion stability is ensured even at a high extrusion rate.