Single Screw Extruder With Plunger Feeder
The present single screw extruder is directed to a materials extrusion device including a twin screw extruder with a plunger feeder. It includes a screw extruder having a main housing, a materials advancing screw, a screw drive mechanism, a feed port for inputting materials to be extruded and an extrusion outlet port. It also includes a plunger feeder having an elongated, upwardly biased (non-horizontal) plunger housing, e.g., a cylinder, with a plunger.
The following patents are representative of various types of extruders:
U.S. Pat. No. 7,229,205 B2 to Schunk et al. describes a drive unit for operating a plastics injection sheet production extruder including a rotatably supported bushing intended for accommodation of an extruder screw and a rotor which includes a hollow shaft and is defined by an inner diameter sized to allow passage of the bushing and accommodated extruder screw through the rotor. The rotor is hereby detachably connected with the receiving member in fixed rotative engagement.
U.S. Pat. No. 7,168,944 B2 to Schad describes an energy efficient drive system provided for use on typical injection molding machines whereby a single electric motor drives both the extruder screw and a hydraulic motor that continuously charges a hydraulic accumulator during the extrusion process. During the injection cycle, the charge in the accumulator is directed to stroke the extruder screw and inject melt into the mold cavities. Another embodiment utilizes a similar arrangement on the clamp mechanism of the injection molding machine whereby the charge in the accumulator is directed to hold the mold closed during the injection cycle.
Although particular embodiments of the twin screw extruder have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the single screw extruder as defined in the appended claims.