Abstract: A Transfermix cold feed extruder having a plasticizing section that includes a plurality of screw flights therein in a transfer zone that is formed over a common length of the screw and barrel of the extruder. In the transfer zone, a helical groove in the screw varies in cross section from a full area to a zero area, and a helical groove of opposite hand in the barrel correspondingly varies in cross section from a zero area to a full area. The extruder is provided with a set of flow deflectors in a cut in the screw positioned immediately upstream of the plasticizing section. By the coaction of the flow deflectors with the plurality of screw flights, an increase of throughput for difficult-to-extrude compounds, with an improvement in the quality of the extrudate, is obtained in a surprising manner.

Abstract: A plasticizing unit is provided for palsticizing material which is subsequently supplied to an injection molding press. The unit includes a screw disposed in a barrel which has an inlet, an outlet, a reservoir zone portion, and a plasticizing zone portion. The plasticizing zone portion of the barrel and the screw each have a continuous helical groove of opposite hand as the other groove and the grooves transfer material therebetween to effect plasticizing of the material. The reservoir zone portion of the barrel receives a shot volume of material which has been plasticized during passage through the helical grooves of the barrel and the screw. A volume displacement member which is axially movably disposed in a bore of the screw is movable within the reservoir zone portion to selectively control the shot volume of plasticized material received in the reservoir zone portion.

Abstract: A single-rotor cold feed extruder having a barrel and a screw and incorporating a transfermix plasticizing/mixing section is disclosed. The extruder is provided with a fixed set of flow-interrupters/deflectors carried by the barrel and positioned in a circumferential cut in the screw downstream of the transfermix section. The extruder is characterized by radially movable throttle members which are located around the flow interrupters/deflectors so as to provide an increase of throughput for and improved quality of difficult-to-extrude compounds.

Abstract: The increasingly high standards of consistency and uniformity demanded of cold feed rubber extruders are met by providing notches in the flights of the screw at least in the feed-inlet of the extruder. The notches are at a lead-angle greater than that of the extruder screw flights, so to pull the rubber and advance it positively. Throttling means are used to adjust the amount of squash-back and there is an independently variable-speed drive for a feed roller in the feed inlet.

Abstract: An extrusion apparatus having a barrel and a rotatable threaded screw coaxially positioned therein is disclosed. The apparatus includes an upstream inlet section having an opening therein for receiving material to be processed by the apparatus, a compression section downstream of the inlet section, and a mixing or plasticizing section downstream of the compression section. The interior surface of the barrel is provided with an undercut therein which intercommunicates the feed opening with the compression section and has a portion thereof which extends downstream in the compression section about the interior surface of the barrel with a continuously decreasing cross-sectional area. The undercut may be formed in a cylindrical insert carried within the barrel and, in an alternate embodiment, a second undercut cylindrical insert positioned about the first insert and rotatable relative thereto may be employed to vary the cross-sectional area of the undercut.

Abstract: This invention provides in a continuously operating device having a mixing section comprising opposite-handed helical threads in each of the two relatively rotatable components which threads vary in cross-sectional area in complementary fashion so as to produce a layer-by-layer material transfer and shear working between the said components, that the said opposite handed helical threads in said mixing section complement one another substantially also in respect to their helix-angles to the extent that if one helix angle is between 0.degree.and 45.degree. the other is between 45.degree. and 90.degree., to bring about, viewed with respect to the shear-plane-area, a subdivision sufficient for the mixing and compounding requirement.

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.