Abstract: An apparatus for heating and blending thermoplastic material prior to delivering the material into the barrel of an extruder. The apparatus, has an elongated housing which contains two intermeshing feed screws that are driven to rotate in the same direction. Controlled heating is provided by electric band heaters which encircle the exterior of the housing, and electric cartridge heating elements fitted into aluminum cores that are received by an axial bore in each of the feed screws.

Abstract: An apparatus for heating and blending thermoplastic material prior to delivering the material into the barrel of an extruder has an elongated housing which contains two intermeshing feed screws that are driven to rotate in the same direction. Controlled heating is provided by electric band heaters which encircle the exterior of the housing, and electric cartridge heating elements fitted into aluminum cores that are received by an axial bore in each of the feed screws.

Abstract: The present invention provides a dual flow divider for use on an extruder. The flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as is practically possible. The relative flow in the respective channels can be varied by rotating a diverter valve that extends to a position adjacent the central entry of the flow divider, i.e., where the flow begins to divide. The flow channels and control end of the diverter valve are specially configured to avoid any shape or surface conditions that would impose heat-generating restrictions to material flow, and/or allow areas of stagnation in the flow stream. More specifically, the flow channels are machined to provide smooth, streamlined transitions at all points along the flow path.

Abstract: The present invention provides a barrel venting system for use on an extruder. Gases that are generated during plasticizing are drawn by vacuum through a filter to remove plastic particles before the gas is exhausted to the atmosphere. To enable cleaning of the filter without interrupting extruder operation, a shuttle valve is provided to allow rapid switching of the gas flow to a second filter. The valve itself includes two disc shaped elements with ports that align in two positions to enable flow to either the first or second filter, as desired.

Abstract: The present invention provides a dual flow divider for use on an extruder. The flow divider is configured to separate the melt stream received from the extruder at a central entry into two flow channels, the respective channels being formed as nearly to identical (mirror image) as is practically possible. The relative flow in the respective channels can be varied by rotating a diverter valve that extends to a position adjacent the central entry of the flow divider, i.e., where the flow begins to divide. The flow channels and control end of the diverter valve are specially configured to avoid any shape or surface conditions that would impose heat-generating restrictions to material flow, and/or allow areas of stagnation in the flow stream. More specifically, the flow channels are machined to provide smooth, streamlined transitions at all points along the flow path.

Abstract: Extruder barrel temperature control apparatus in the form of a plurality of axially spaced tubular shells positioned in end-to-end relationship on the outer surface of a tubular extruder barrel. Each of the shells includes individual resistance heater elements embedded in the shell wall for providing heat to maintain a desired shell temperature. Each shell includes two groups of outwardly extending cooling fins, each group axially spaced from the other, and each group of fins has an associated air blower positioned below the fins and supported by an outer casing surrounding the extruder barrel. The outer casing includes an internal shroud to confine the cooling air flow so it is directed over and along the cooling fins. The heating elements and the blower motors are connected with a suitable control system for providing and maintaining a desired temperature level at the barrel inner surface. Six such shells defining six respective heating and cooling zones are disclosed.

Abstract: A preform carrier adapted to be received in the open end of a wide mouth tubular container preform for internally gripping the preform to permit carrying the preform from a heating station to a container blowing station. The carrier includes a flexible annular gripping member in the form of a gripping and sealing ring that is resiliently flexible in a radial direction, relative to the preform axis, for engaging the inner surface of the preform finish. The gripping member includes an annular sealing ridge on its outermost surface for gripping and sealing against the inner surface of the preform finish. The gripping member is of generally U-shaped configuration, and includes an inner annular U-shaped spring for urging the legs of the sealing ring outwardly to provide a gripping and sealing force against the inner surface of the preform finish.