| 摘要 |
Improvement of the method and apparatus in which a generally equal circumferential distribution in an annular extrusion die is achieved by dividing the flow between inlet (1a, 10) and circular exit orifice (21) into a number of partflows through channels (4, 14) which have generally helical form at least through a portion of each channel, with space (15) provided for overflow between these helical channels. The improvement consists in either a) controlling the overflow by an adjustable insert (101) which provides a variable spacing (15) for the overflow between the helical channels (4, 14), or alternatively b) providing a constraint (115, 116, 117) against the flow in a circularly extending zone after the helical part of the channels, but before the exit orifice and in case of coextrusion before the joining of the components (19, 20). This constraint is adjustable by adjustment means (44, 45) from location to location along its circumference. |
