| 摘要 |
The invention provides a screw (1) for an extruder that can control the temperature on the whole screw including the flight (1b) and avoid an extruded material form adhering one surface of the screw. The screw (1) according to the invention is constructed as follows. A center hole (2) with its front end closed is formed in the center of the screw core (1a), and an inner tube (3) is inserted in the center hole (2) from the base end side of th e center hole. The front end of the inner tube (3) opens at a position corresponding to the base end of the flight (1b). A ring seal member (4) occludes a space between a front outer surface of the inner tube (3) and the corresponding inner surface of the center hole (2). Thus, a main channel (5) of a dual tube is formed which has an outward channel (5a) inside the inner tube (3) and an inward channel (5b) outside the inner tube (3). On the other hand, on the backside of the flight (1b), a jacket-form spiral channel (6) is formed along the whole backside. The front end end the rear end of the spiral channel (6) each communicate with the outward channel (5a) and inward channel (5b) of the main channel (5), respectively, through radial communicating holes (6). <IMAGE> |
