Patent attributes
A pipe extrusion die may be provided having an inner flow passageway having a first cross-sectional area, and an outer flow passageway having a second cross-sectional area, both being in communication with an inlet flow passageway. A ratio adjusting tube may be movably disposed in blocking engagement between the inlet flow passageway and the inner flow passageway. The ratio adjusting tube and the outer flow passageway both may be substantially concentric with the inner flow passageway. Material may be distributed from the inlet flow passageway to the inner and outer flow passageways. The method and apparatus may allow for the manual and automatic control of the proportion of material distributed between the inner and outer flow passageways by adjusting the position of the ratio adjusting tube in relation to a passageway between the inlet flow passageway and the inner flow passageway, based on various operating parameters.
