Process employing coextrusion feedblock
US4125585A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 17, 1976 |
| Grant date | Nov 14, 1978 |
| Priority date | — |
| Expiry date | Dec 17, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29C48/21
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A feedblock fashioned from a plurality of plates is disclosed which distributes two flows of dissimilar synthetic resinous materials into a radially stratified annular form for extrusion by a pipehead die. The feedblock is mounted on a pipehead with the plurality of plates defining material flow channels for three strata. Independently operable valves vary stratum thickness and assure radially matched flow conditions between strata at confluence. Each stratum is independently accelerated through a convergent channel to assure that a uniform circumferential distribution of flow conditions develops. Moreover, two strata are developed through channel systems which do not induce circumferential maldistribution. The third stratum is handled to eliminate circumferential maldistribution. Accordingly, the process and apparatus develop stable annular flow with radial stratification having neither radial nor circumferential maldistributions that may later interact to distort the strata.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.