Spiral fed multi-layer tubular die
US6305922A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 25, 1995 |
| Grant date | Oct 23, 2001 |
| Priority date | — |
| Expiry date | Jan 25, 2015 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/3363
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
An extrusion die apparatus for extruding a multiple layer tubular product comprising an elongated cylindrical mandrel and a plurality of annular die elements mounted co-axially one behind the other on the mandrel forming contiguous annular thickness control passages between the die elements and the mandrel. The die elements have inner and outer conical surfaces inclined rearwardly at a predetermined angle with respect to the longitudinal axis of the mandrel. The die elements are nested together with the outer conical surfaces of one die element facing the inner conical surfaces of an adjacent die element. The inner and outer conical surfaces form conical passages therebetween which communicate with the annular thickness control passages and a helical groove is provided on the outer conical surface of each die element. Means are provided for delivering a molten thermoplastic material to the conical passages wherein the material is substantially uniformly distributed over the outer conical surface containing the helical groove.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.